JP4027129B2 - Image forming apparatus - Google Patents

Description

[0001]
  The present inventionRegarding image forming apparatusIn particular, the present invention relates to setting of image forming conditions in an image forming apparatus that forms an image according to an electrophotographic system.
[0002]
[Prior art]
In recent years, computers around the world have been linked, mainly on the Internet, and various information is frequently searched and browsed using this. As a representative method, a computer linked with a WWW (World Wide Web) dedicated software (hereinafter referred to as a browser) for browsing information is connected via a network, and information on the WWW server is displayed. Is generally referred to from the computer according to HTTP (Hyper Text Transfer Protocol).
[0003]
Also, with such a browser, the information on the browsed WWW server can be captured and stored in a computer. Therefore, various information on the WWW server can be printed and saved as a recording medium by outputting the data stored in the computer to an image output device or the like having a printing function and printing as necessary. It has been broken.
[0004]
As such an image output apparatus, a laser beam printer that forms an image in accordance with an electrophotographic method and an ink jet printer that records an image in accordance with an ink jet method are generally used. In such a printer, image processing is performed on image data transmitted from a host device such as a connected computer, and the image data is converted into image data suitable for the printer.
[0005]
However, since the conventional printer apparatus always performs fixed image processing regardless of the type and content of image data, the following problems occur.
[0006]
Image data, such as photos, emphasizes gradation, and image data, such as illustrations, emphasizes resolution, but the same image processing is performed on all image data. In some cases, the resolution of image data such as illustrations may be impaired.
[0007]
Since only a certain gamma conversion process is performed, it is difficult to output with an optimum color according to each image data. Similarly, since only the same under color process is performed, it is difficult to output with an optimum color.
[0008]
In order to solve such a problem, Japanese Patent Application Laid-Open No. 2000-207164 discloses an image forming apparatus that forms an image based on image data acquired from a network. In other words, it is disclosed to perform control so as to execute image processing in accordance with the type of image data by determining the required imaging.
[0009]
Further, as an image output apparatus, an image forming apparatus such as an electrophotographic digital copier that converts a document image into image data by a reading apparatus and obtains a printed image is increasingly used. Such an image forming apparatus is configured to transfer image data transmitted from a computer to the image forming apparatus via an external device.
[0010]
The external device includes various processing circuits for accessing the network to acquire image data, developing the acquired image file into a raster image, and performing image processing so that an appropriate print image can be obtained. Although the hardware scale has been large, in recent years, integration of hard circuits has progressed, and there is a configuration in which such an external device is built in the image forming apparatus.
[0011]
Also in the printer apparatus as the peripheral device of the computer as described above, recently, various image processing boards are selectively mounted according to the user's request so as to achieve both the cost and the function desired by the user. Product specifications are required. That is, part or all of the image processing circuit is required to have a replaceable configuration.
[0012]
Thus, a design that can make the configuration of the image processing circuit flexible is required for the image output apparatus. On the other hand, image processing techniques are becoming more and more sophisticated, and various image processings according to characteristics of image data such as various original images and characters have been proposed. There has also been proposed a configuration in which appropriate image processing is performed automatically or in response to a user instruction. In this case, it is difficult to distinguish between processing performed by the image processing circuit and engine control on the printer engine side. It is coming.
[0013]
For example, in an image forming apparatus having a function of predicting toner (developer) consumption according to image data and performing toner density control, image processing such as gamma conversion, which is closely related to printer control, is performed. I handle it on the printer engine side. That is, as part of controlling the image forming means of the image forming apparatus, the printer engine performs image processing mainly in accordance with the engine characteristics and corrects the engine characteristics, and the printer engine receives the image data. Thus, the image data is integrated, the toner consumption is predicted from the integration result, and the toner supply to the developing device is controlled.
[0014]
Further, a toner patch image is formed on the photosensitive drum, the toner density in the developing device is measured, and toner replenishment control is performed with high accuracy from the integration result of the image data and the measured toner density information in the developing device. An image forming apparatus is also devised.
[0015]
On the other hand, when configuring an advanced and large-scale image processing circuit, the main image processing function is not performed on the printer engine side of the image forming apparatus, and the main image processing is performed on the image processing board. Thus, attempts have been made to provide the printer engine itself at a low cost.
[0016]
[Problems to be solved by the invention]
As described above, when the configuration of the image processing circuit of the image forming apparatus is reviewed, the configuration of the image processing circuit is made flexible so that various image processing functions can be provided instead of the printer engine side. It can be seen that it is preferable to handle information necessary for printer engine control on the processing board side.
[0017]
However, as described above, in the conventional image forming apparatus, particularly regarding toner replenishment control that is closely related to printer characteristics, necessary information is generally handled only on the printer engine side.
[0018]
Therefore, when performing various image processing, it is difficult to consolidate main image processing functions on the image processing board.
[0019]
In addition, when determining the image formation conditions in the electrophotographic process such as charging, exposure, latent image, development, transfer, and fixing, the image quality is further improved by appropriately setting the image formation conditions according to the characteristics of the image. It is known that it can be done.
[0020]
However, in current image forming apparatuses, it is difficult to say that the image forming process conditions are sufficiently optimized.
[0021]
Specifically, in order to optimize the image forming conditions in accordance with the type of image, it is necessary to set an image to be printed by either the user or the image forming apparatus. In this case, in an apparatus in which the user sets image forming conditions, the user's operation at the time of printing becomes complicated and the operability deteriorates. Furthermore, if the user forgets the setting or sets it incorrectly, optimum image formation will not be performed.
[0022]
On the other hand, an apparatus that automatically sets image forming conditions on the image forming apparatus side performs an extraction process for extracting features of image data to be printed in an image processing unit. Generally, the type is determined, and the image forming condition in the apparatus is set to an optimum condition. In this case, since it is necessary to perform the feature extraction process of the image data before actually printing, it takes time to set the image forming conditions, and the time until actually starting the printing operation becomes longer. , Throughput will decrease.
[0023]
  The present invention has been made in view of the situation as described above, and even when an image processing board having a flexible configuration capable of performing various image processing is used in an image forming apparatus, the image processing apparatus is appropriately used. The image forming conditions can be set.Image forming deviceThe purpose is to provide.
[0024]
  In order to achieve the above object, an image forming apparatus as one aspect of the present invention includes:
  Storage means for storing image data;
  Image processing means for executing image processing on the image data stored in the storage means;
  By the image processing meansimageImage forming means for forming an image using a developer based on the processed image data.An image forming apparatus comprising:
  The image processing meansIs, The image dataDifferent image processing depending on the image type, and, The image forming meansTo the image type,
  The image forming means includes theAfter performing a calibration operation according to the notified image typeThe image processing meansImage formation based on image data processed withIt is characterized by doing.
[0025]
  That is, in the present invention, the image data is stored in the storage means, and the image processing means executes image processing on the image data stored in the storage means, and the image dataDifferent image processing depending on the image type, and, Image forming meansTo notify the image type,In the image forming means,After performing a calibration operation according to the notified image typeThe image processing meansAn image is formed based on the image data processed by theBy image processing meansimageAn image is formed using a developer based on the processed image data.
[0026]
In this case, the main image processing functions can be integrated into the image processing board as the image processing means, and a flexible configuration image processing board that can perform various image processing is used in the image forming apparatus. However, an appropriate image forming condition based on the image data can be set, and an image printing operation suitable for the type of image to be printed can be performed.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
First, image processing performed in the embodiment described below will be briefly described.
[0028]
For example, on the Internet, GIF and JPEG are generally used as image file formats. Of these, the GIF file format is a file format in which an image is compressed and stored by lossless compression, and the number of colors that can be displayed is limited to 256 colors. For this reason, the GIF file format is often used for image data that does not require such a large number of colors as illustrations and drawings.
[0029]
The JPEG file format is a file format that is compressed and saved by irreversible compression, and can display a very large number of colors such as about 16.77 million colors. For this reason, this JPEG file format is often used mainly for image data of natural images such as data obtained by digitizing photographs.
[0030]
On the other hand, when printing an image by an electrophotographic method or the like, if the resolution of the image to be printed is increased, it is difficult to make the waveform of an analog signal used as a pattern signal by pulse width modulation (PWM) or the like an ideal triangular wave. Therefore, it becomes difficult to print with ideal gradation.
[0031]
Therefore, in the present embodiment, image data for which priority is given to resolution is printed at a high resolution, and image data for which priority is given to color gradation is printed at a low resolution.
[0032]
Furthermore, image data such as illustrations and diagrams and image data such as photographs and natural images often have different settings for image enhancement processing or smoothing processing. In this embodiment, according to the format of each image data Image enhancement or smoothing can be set.
[0033]
In addition, when printing RGB image data with an electrophotographic printer, the image data expressed in RGB is C (cyan), M (magenta), Y (yellow), K (black). It is necessary to convert it to a density value and send the converted image data to a printer. In this case, in the gray image printed using the CMY toner, the gray color becomes a grayish color, so it is better to print the gray portion with only the black (K) toner. There is a case. On the other hand, when the gray portion is printed with only the black toner, in the case of a gradation image that smoothly changes from gray to another color, the reproduced gradation property of the gradation portion is impaired. Therefore, in such an electrophotographic printer, image formation is generally performed by combining CMY toner and K toner at an appropriate ratio. The ratio of CMY and K in this case is referred to as Under Color Removal (UCR). In the present embodiment, it is possible to set under color removal according to the format of each image data.
[0034]
Also, in the case of a printer such as a binary printer where the area of one pixel is not variable or the area of one pixel can be changed only by a very limited amount, An image having gradation can be printed by changing the number of colored pixels and the combination of these colored pixels. Such an image representation method is called an area gradation method. According to this method, the original image data is processed by a dithering process or an error diffusion method, so that the image is composed only of colors that can be printed by the printer. Can be converted to data and printed. Even in such area gradation processing, by applying optimal conversion processing according to when printing image data such as photographs and when printing image data such as illustrations, the format of each image data The area gradation processing can be set accordingly.
[0035]
[First Embodiment]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0036]
As a first embodiment, using the HTTP protocol, a command is transmitted to a server that holds desired image data instructed by the user using the operation unit, and a response from the server is received. An image forming apparatus that acquires image data stored in the server and forms an image will be described as an example.
[0037]
FIG. 1 is a block diagram illustrating a configuration of the image forming apparatus 1 according to the present embodiment. Here, the image forming apparatus 1 is connected to a network 32.
[0038]
In FIG. 1, reference numeral 2 denotes an image memory, which stores and holds, for example, image data from the document image reading unit 201 or image data input via the network 32 via the network interface 3. The network interface 3 controls communication with other devices connected to the network 32 via the network 32. An image processing circuit 4 performs various types of image processing on the image data stored in the image memory 2 and outputs the processed image data to the printer 5. The printer 5 functions as an image forming unit that inputs image data from the image processing circuit 4 and forms an image on a recording medium such as paper.
[0039]
An operation unit 6 is used by the user to specify a location (server or the like) where image data to be printed is stored using the printer 5. A server 7 is connected to the network 32 and holds various image data. Reference numeral 30 denotes a system bus, through which data is transmitted and received between the CPU 101 that controls the operation of the entire image forming apparatus 1 of the present embodiment and each unit. A video bus 31 is used to transmit image data generated by the image processing circuit 4 to the printer 5. The network 32 is a communication path for connecting the image forming apparatus 1 and the server 7 to each other and transmitting / receiving various data between these apparatuses. A memory 102 is used as a work area for temporarily storing programs executed by the CPU 101 and various data during the operation of the CPU 101.
The CPU 202 of the printer 5 transmits and receives data to and from the CPU 101. The CPU 202 performs a series of printer engine processes such as paper conveyance control, toner image formation and toner supply operation of the printer 5, transfer onto the paper, and fixing processes. Take control.
[0040]
When reading from a document image, by pressing the copy key of the operation unit 6, the image data read by the reading unit 201 is read into the image memory 2, and predetermined image processing is performed by the image processing unit 4. The transmitted image data is sent to the printer 5 to form an image on the recording medium.
[0041]
Here, the HTTP protocol will be described. The HTTP protocol is a service on the TCP / IP protocol used for transferring data described in HTML (Hyper Text Markup Language), image data, and the like. This is normally used in a system in which a client computer that issues a data transfer request and a server that holds data are connected by a network.
[0042]
On the client computer, an HTTP client is operated, and in this HTTP client, a user inputs the position of data on the server in an instruction format called URL, which specifies the position where the data is held. . Thus, the HTTP client issues an information transfer request to the server in response to the input.
[0043]
The HTTP protocol includes a GET command that is a command for requesting data and a HEAD command that is a command for requesting related information related to the data. What kind of data is acquired by the HEAD command? Generally, it is generally determined whether the data is data, and then the data is acquired by a GET command, and processing is performed based on the acquired data.
[0044]
Among the related information that can be acquired by the HEAD command, there is format information of the data as well as information such as the size and update date / time of the data. The format information of this data is called “Content-type”. According to this, for example, an extension such as “text / html” for data described in HTML, “image / GIF” for GIF image data, and “image / JPEG” for JPEG image data is added. Therefore, it is possible to determine what kind of data is from this extension.
[0045]
For example, if the host name of the server 7 is “host.co.jp” and the location of the data to be acquired is “/pub/image.GIF”, “http: // host. By inputting the URL “co.jp/pub/image.GIF”, the HTTP client first issues a HEAD command for “/pub/image.GIF” to the server “host.co.jp”. .
[0046]
Upon receiving this, the server 7 transmits the format information of the data “/pub/image.GIF” to the HTTP client that issued the HEAD command as a reply to the HEAD command.
[0047]
The HTTP client that has received the reply of the HEAD command then issues a GET command for “/pub/image.GIF” to the server “host.co.jp”.
[0048]
The server 7 that has received this GET command transmits the data “/pub/image.GIF” to the HTTP client that issued the GET command as a reply to the GET command.
[0049]
The HTTP client that has received the reply of the GET command can receive the data of the format information “/pub/image.GIF” received as a reply to the HEAD command, and can process the received data in this way.
[0050]
In this way, the HTTP client can acquire the specified data stored in the specified server 7 together with the related information of the data based on the URL input from the operation unit 6. The process flow will be described later with reference to the flowchart of FIG.
[0051]
Next, the configuration of the image processing circuit 4 of the present embodiment will be described. FIG. 2 is a block diagram showing a configuration of the image processing circuit 4 of the present embodiment.
[0052]
In the figure, reference numeral 8 denotes a DMA data transfer circuit, which performs DMA transfer control of image data from the image memory 2 to the image processing circuit 4. A LOG conversion circuit 9 converts RGB image data into CMY image data. A UCR circuit 10 performs UCR processing on CMY image data to generate CMYK image data 40. Reference numeral 11 denotes a PWM (pulse width modulation) circuit, which generates a laser drive signal 42 for performing laser lighting control from CMYK image data.
[0053]
33 is an R data signal meaning red component data of the image data, 34 is a G data signal meaning green component data of the image data, 35 is a B data signal meaning blue component data of the image data, and 36 is C data signal representing cyan component data of image data, 37 M data signal representing magenta color component data of image data, 38 Y data signal representing yellow component data of image data, 39 It is a color selection signal for selecting a color for image formation. 40 is a data signal selected from CMYK data, 41 is a clock signal which is a reference synchronization signal for performing PWM processing, and 42 is a laser drive signal for controlling laser lighting.
[0054]
The DMA data transfer circuit 8 is connected to the system bus 30 and is controlled by the CPU 101 that controls the entire image forming apparatus 1 via the system bus 30. When image data held in the image memory 2 is transferred to the image processing circuit 4 by DMA transfer under the control of the DMA data transfer circuit 8, the CPU 101 first sends R, The address of the image memory 2 holding the image data of G and B and the data size for DMA transfer are set. Thereafter, in synchronization with the operation of the printer 5, the DMA data transfer circuit 8 sequentially reads R, G, B data from the instructed address of the image memory 2 by the DMA, and the read data is a LOG conversion circuit 9. Are output as an R data signal 33, a G data signal 34, and a B data signal 35. The output of RGB data to the LOG conversion circuit 9 is performed in synchronism with R, G, and B data. That is, the R, G, B data of each pixel of the image data is output simultaneously.
[0055]
From the R data signal 33, the G data signal 34, and the B data signal 35 input to the LOG conversion circuit 9 in this way, a C data signal 36, an M data signal 37, and a Y data signal 38 are generated and output by LOG calculation. The At this stage, the luminance data of R, G, and B data is converted into density data of C, M, and Y data.
[0056]
The C data signal 36, M data signal 37, and Y data signal 38 output from the LOG conversion circuit 9 are input to the UCR circuit 10. The UCR circuit 10 extracts a black component that is a common part from each of C, M, and Y data and outputs the extracted black component. In this black component extraction, for each pixel, the color having the minimum value of each of the C, M, and Y data is determined, and the minimum value and the preset coefficient are integrated, thereby obtaining black toner data. Is determined, and the value of each C ′, M ′, Y ′ actually used for image formation is obtained by subtracting the value of this K data from each of the C, M, Y data. This is realized by calculating.
[0057]
For example, when the black toner data generation coefficient is 80%, C = 20, M = 90, and Y = 100, the minimum value is “20”. image data,
C ': 4 (C-K)
M ': 74 (M-K)
Y ': 84 (Y-K)
K: 16 (20 × 80% = 16)
Is generated.
[0058]
The UCR circuit 10 is supplied with a color selection signal signal 39, which is a necessary signal because the printer 5 employs an image forming method in which images of C, M, Y, and K are sequentially formed one by one. Yes, it is a signal for selecting which image data of C ′, Y ′, M ′, K is to be output at the time of image formation of C, M, Y, K.
[0059]
In response to an input from the color selection signal signal 39, the data signal 40 is output as one of C ′, Y ′, M ′, and K.
[0060]
The data signal 40 output from the UCR circuit 10 is subjected to pulse width modulation in the PWM circuit 11 by a clock signal 41 that is a triangular wave. By this pulse width modulation, for example, the data signal 40 input as 8-bit data is converted into a pulse wave modulated so as to become a signal having a pulse width corresponding to the value of the data signal 40 in synchronization with the clock signal 41. Modulated. Further, in the PWM circuit 11, the input clock signal 41 can be set, for example, to divide by two and perform PWM at a frequency that is ½ of the clock signal 41.
[0061]
In response to the output of the image data signal 40 of any one of C ′, Y ′, M ′, and K by the color selection signal 39, the image data signal is corrected by a lookup table (hereinafter referred to as LUT) 302. After that, the image data is sent to the integrator 301, and the corrected image data is integrated by the integrator 301. The integrator 301 performs integration corresponding to each toner color, and the CPU 101 reads the integration result and stores it in the memory 102. The CPU 101 reads out the integration result stored for each toner color from the memory 102 and immediately notifies the CPU 202 of the printer 5 as toner consumption amount prediction data.
[0062]
The LUT 302 is composed of a random access memory that can be rewritten by the CPU 101, and stores correction data for correcting image data in accordance with printer characteristics for each toner color. For example, an image whose resolution is to be emphasized is PWM-modulated with the period of the clock signal 41, but an image whose tone reproducibility is to be emphasized is PWM-modulated with a half frequency of the clock signal 41, so that the same image data is used. Even if there is a slight difference in toner consumption, correction data capable of integrating the correct toner consumption is stored in the LUT 302, and the contents of the LUT 302 are changed depending on which PWM modulation mode is used for printing. Try to rewrite. Alternatively, both correction data may be stored, and the upper address of the LUT 302 may be controlled from the CPU 101 so that the correction data to be referenced in the LUT 302 is switched according to the PWM modulation mode.
[0063]
Next, the configuration of the printer 5 of the present embodiment will be described. FIG. 3 is a block diagram illustrating the configuration of the printer 5 of the present embodiment.
[0064]
In the figure, reference numeral 12 denotes a semiconductor laser, which outputs laser light in accordance with an input signal. Reference numeral 13 denotes a polygon mirror, whose regular hexagonal side surface is mirror-finished and rotates according to the driving of the polygon motor 14. A photosensitive drum 15 forms a latent image with laser light, and a toner image is formed by electrostatically adsorbing toner from a developing device to the latent image. Reference numeral 16 denotes a revolver that holds toner cartridges of C, M, Y, and K, and rotates according to the color to be developed. Reference numeral 17 denotes a C (cyan) toner cartridge, 18 denotes an M (magenta) toner cartridge, 19 denotes a Y (yellow) toner cartridge, and 20 denotes a K (black) toner cartridge. Each toner cartridge includes a toner bottle that stores toner and a developing unit that stores a two-component developer including a magnetic carrier and toner. In the development process for each toner color, the developing device sleeve rotates to develop the electrostatic latent image with toner from the developer on the sleeve, and a predetermined amount of toner is supplied from the toner bottle into the developing device. Thus, the developer toner concentration of the developing device in the toner cartridge is kept substantially constant.
[0065]
A transfer drum 21 adsorbs the paper and transfers the toner on the photosensitive drum 15 onto the paper. Reference numeral 22 denotes a fixing drum for fixing the toner onto the paper, 23 denotes a paper feed cassette that holds the paper and feeds the paper during image formation, 42 denotes a laser drive signal, 43 denotes a laser beam emitted from the semiconductor laser 12, 44 Is a paper conveyance path.
[0066]
The printer 5 is a printer that forms an image by an electrophotographic method, and forms an image on a sheet with toners of four colors of C (cyan), M (magenta), Y (yellow), and K (black). It is. When forming an image, first, the paper loaded in the paper feed cassette 23 is fed, and the paper is transported through the paper transport path 44 and is attracted to the transfer drum 21 and sticks to the surface of the transfer drum 21. The transfer drum 21 rotates at a constant speed, and the paper moves in accordance with the rotation of the transfer drum 21.
[0067]
On the other hand, when the printer 5 performs printing, a laser drive signal 42 is supplied from the image processing circuit 4. The supplied laser drive signal 42 is one of C, M, Y, and K data signals PWMed by the PWM circuit 11. First, the C data signal is input. When this data signal is on, the laser light source of the laser 12 emits light and a laser beam 43 is output. The laser beam 43 thus output is applied to the polygon mirror 13. The polygon mirror 13 is rotated by the rotational drive of the polygon motor 14, and the laser beam 43 is scanned from end to end of the photosensitive drum 15 by this rotation. This one scanning becomes one scanning line in image formation. A latent image is formed on the photosensitive drum 15 by the scanning of the laser beam. This latent image is a latent image having electrical characteristics in which a portion irradiated with laser light has a high potential and a portion other than that has a low potential.
[0068]
Thus, the latent image formed on the photosensitive drum 15 is first transferred to the sleeve at the portion where the C toner developing sleeve and the photosensitive drum 15 in the C toner cartridge 17 arranged in advance at the portion where the revolver 16 and the photosensitive drum 15 are in contact with each other. In contact with the negatively charged cyan toner stored in the developer coated on the surface. The cyan toner is developed by being attracted by an electric suction force only to a portion of the photosensitive drum irradiated with the laser beam. The portion of the photosensitive drum 15 where the toner is adsorbed moves to a portion in contact with the transfer drum 21 by the rotation of the photosensitive drum 15. In the portion where the transfer drum 21 and the photosensitive drum 15 are in contact, the toner adsorbed on the photosensitive drum 15 is transferred onto the paper adsorbed on the transfer drum 21.
[0069]
Next, the revolver 16 is rotated 1/4 so that the M toner cartridge 18 comes into contact with the photosensitive drum 15, and an M data signal is input as a laser drive signal 42. The toner image is transferred. In the same manner, development with Y and K toners is also performed, and toner images of C, M, Y, and K colors are transferred onto the sheet adsorbed on the transfer drum 21.
[0070]
Thereafter, the sheet is separated from the transfer drum 21 and passes between the two fixing devices 22 through the sheet conveyance path 44. At this time, the toner that is heated and pressurized by the fixing device 22 and transferred onto the paper is fixed onto the paper and discharged out of the printer 5. Printing is executed by the above operation.
[0071]
When the printer 5 performs the printing operation as described above, the toner in the developing device is consumed. Therefore, in the two-component development method including the toner and the magnetic carrier, the toner density is appropriately set so as to maintain an appropriate toner density. It is necessary to perform toner replenishment control for replenishing consumed toner into the developing device.
[0072]
Therefore, based on the toner consumption amount prediction information for each toner color notified from the CPU 101 to the CPU 202 of the printer 5 along with the printing operation, the CPU 202 performs C, M, Y, K toner cartridges 17, 18, 19, Control is performed so that toner is replenished from the 20 toner bottles into each toner color developer.
[0073]
In the present embodiment, the configuration of the printer engine having the transfer drum 21 has been described. However, instead of the transfer drum, four color toner images are sequentially superimposed on an intermediate transfer member such as an intermediate transfer drum or an intermediate transfer belt, and then conveyed. An engine form that performs batch transfer on the sheet that has been used may be used.
[0074]
Next, the processing operation in the image forming apparatus 1 of the present embodiment will be described with reference to the flowchart of FIG. FIG. 4 is a flowchart showing a control process executed by the CPU 101 in the image forming apparatus according to the present embodiment, and a program for executing this process is stored in the memory 102.
[0075]
The image forming apparatus 1 includes an operation unit 6. The operation unit 6 includes buttons, a display, and the like, and is used by a user to operate the image forming apparatus 1. In this operation unit 6, the user designates a place where data to be printed exists by URL. Until this input is made, the image forming apparatus 1 waits for input (step S1). When a URL is input in step S1, the process proceeds to step S2, where the structure of the input URL is analyzed, and the address of the server holding the desired data and the position of the data to be acquired in the server are determined. Identify. Here, it is assumed that there is data to be acquired in the server 7.
[0076]
In step S3, a HEAD command for the data to be acquired is issued to the server 7. This HEAD command is transmitted to the server 7 via the network interface 3 and the network 32.
[0077]
The server 7 that has received the HEAD command generates format information for the HEAD command based on the information related to the designated data, and transmits it to the image forming apparatus 1 via the network 32 and the network interface 3. As a result, when the format information from the server 7 is received in step S4, the process proceeds to step S5, where the “Content-type” information is extracted from the format information from the server 7 and stored.
[0078]
In step S6, the server 7 issues a GET command for the data to be acquired. This GET command is issued to the server 7 via the network interface 3 and the network 32.
[0079]
As a result, the server 7 transmits the data designated by the GET command to the image forming apparatus 1 via the network 32 and the network interface 3.
[0080]
When the reply from the server 7 is received in this way, the process proceeds from step S7 to step S8, and image data is generated in the image memory 2 based on the data received from the server 7. Next, the process proceeds to step S9. If the “Content-type” stored in step S5 is a JPEG image, the process proceeds to step S10. Otherwise, the process proceeds to step S12. In step S10, the image processing circuit 4 is set for JPEG image processing. That is, the UCR circuit 10 is set to UCR 80%, and the PWM circuit 11 is set to perform PWM at a half frequency.
[0081]
The correction data for the LUT 302 stores correction data for PWM modulation at a half frequency.
[0082]
Further, based on the “Content-type” information, the CPU 101 notifies the CPU 202 that the image is in JPEG format with priority on gradation. As will be described later, the CPU 202 sets gradation-priority process conditions in the image forming unit when printing the corresponding image.
[0083]
On the other hand, when it is determined in step S9 that the image is not a JPEG image, the process proceeds to step S12 to set the GIF image for the image processing circuit 4. That is, the UCR circuit 10 is set to UCR 100%, and the PWM circuit 11 is set to perform PWM at the same frequency as the clock signal 41.
[0084]
The correction data for the LUT 302 stores correction data for PWM modulation at the same frequency as the clock signal 41.
[0085]
Further, based on the “Content-type” information, the CPU 101 notifies the CPU 202 that the image is in the resolution priority GIF format. As will be described later, the CPU 202 sets resolution-priority process conditions in the image forming means when printing the corresponding image.
[0086]
In this way, after image processing and PWM are executed in step S10 or step S12, in step S11, the printer 5 executes image formation based on the image processing and PWM processed image data. Further, according to the JPEG image or the GIF image, image formation is performed at a resolution suitable for each, and image data corrected by correction data corresponding to each resolution is accumulated by an accumulator, and the printer 5 The result of integration is notified as toner consumption prediction information.
[0087]
When copying a document image, the operation unit 6 designates the gradation priority mode or the resolution priority mode, and the CPU 101 performs image processing and PWM modulation mode according to the designated mode from the operation unit 6. It may be configured to set the gradation priority mode or the resolution priority mode.
[0088]
As described above, image formation can be performed based on the image data stored in the server 7 designated by the operation unit 6.
[0089]
According to this processing, since a black component is extracted from a JPEG image with UCR 80%, it is possible to generate an image with excellent tone connection of an image that transitions from black to another color. Since PWM is performed at 1/2 frequency, an image with excellent gradation can be generated.
[0090]
As for the GIF image, since the black component is extracted with UCR of 100%, a light gray image is formed only with black toner, and this is a problem in an image generated by combining C, M, Y, and K. Can be prevented from becoming gray due to pure black. Further, since PWM has the same frequency as the supplied clock signal 41, it is possible to form a high-resolution image in which jaggy is not noticeable.
[0091]
As described above, according to the present embodiment, a JPEG image is formed by image processing suitable for printing a natural image such as a photograph, and a GIF image is formed by image processing suitable for printing an illustration or the like. An image is formed.
[0092]
The image processing unit performs optimum image processing on the image data, and by integrating the image data, predicts an appropriate toner consumption amount for each toner color and notifies the printer to maintain an appropriate developer toner concentration. The toner replenishment control of the printer unit can be performed so that it can be performed.
[0093]
Here, setting of the process conditions of the image forming unit executed by the CPU 202 of the printer will be described.
[0094]
As described above, the data format (JPEG format or GIF format) of the image to be printed is notified from the CPU 101 to the CPU 202 of the printer unit by the communication unit 201. Then, for the engine of the printer 5, a printing operation is performed by setting process conditions according to the data format.
[0095]
For example, if the charging voltage is Vc, the developing bias voltage is Vd, and the transfer voltage is Vt,
For the JPEG format with priority on gradation,
Vc = V11, Vd = V12, Vt = V13,
For the resolution priority GIF format,
It is assumed that Vc = V21, Vd = V22, and Vt = V23.
[0096]
As described above, an optimum reproduced image can be obtained by switching the setting of the process conditions of the image forming unit according to the format of the image data to be printed.
[0097]
In the above example, it has been proposed to switch all of the charging voltage, the developing bias, and the transfer voltage. Of course, at least one of these conditions may be switched.
[0098]
In addition, although an example in which the charging, development, and transfer voltage values are switched as the process condition parameters has been described, for example, in a configuration in which constant current control is performed, the current values may be switched.
[0099]
For example, if the output current value (transfer current value) of the high-voltage power supply used for transfer is It,
For the JPEG format with priority on gradation,
It = I1
For the resolution priority GIF format,
It is assumed that It = I2.
[0100]
Thus, by changing the transfer current value in accordance with the format of the image data to be printed, optimum image reproduction can be achieved.
[0101]
It should be noted that the CPU 202 on the engine side in advance allows the CPU 202 to select and switch the process condition parameters as described above depending on whether the image data to be printed is in JPEG format or GIF format. The process condition information for each file format is stored as a look-up table in which image feature information and process condition parameters are associated with each other in a non-illustrated non-volatile memory provided inside or outside the CPU 101. When the data feature information is received, the process condition parameter of the image forming means of the printer unit may be changed to the corresponding parameter to optimize the process condition.
[0102]
In this case, for example, parameter information such as Vc = V11, Vd = V12, Vt = V13, or It = I1 is stored as a process condition in the JPEG format at the upper level of the address in the nonvolatile memory of the CPU 202. In the lower part of the address, parameter information such as Vc = V21, Vd = V22, Vt = V23 and It = I2 is stored as process conditions in the GIF format. When the feature information of the image data is received from the CPU 101, the parameter information of the corresponding process condition is read from the address in the nonvolatile memory of the CPU 202 depending on whether it is in JPEG format or GIF format, and image formation is performed. You may comprise so that the optimal conditions may be set to a means.
[0103]
Of course, it goes without saying that the image file and data formats other than the JPEG format and GIF format exemplified here can be supported.
[0104]
For example, when printing a text document, it is particularly necessary to clearly reproduce the edges and fine lines of characters, so it is effective to set the image forming conditions with priority on resolution. Therefore, an image forming process may be performed with priority given to resolution for a file with an extension “.txt”.
[0105]
In addition, by changing the conditions (parameters) of the image forming process to the optimum conditions in this way, it becomes possible to obtain a high-quality print output according to the characteristics of the image. Along with this, the toner consumption may change. In such a case, it is conceivable that the difference between the prediction result of the toner consumption amount in the image processing circuit and the actual toner consumption amount becomes large, causing a problem.
[0106]
An example of such a problem is that when a large amount of printing is performed, the toner replenishment control is not properly performed, the toner density in the developing device cannot be maintained at an appropriate density, and the printing density becomes low. In the worst case, the density of the image may become dark, or in the worst case, the carrier in the developing device may adhere to the photosensitive drum or the developer may overflow, causing damage to the apparatus. .
[0107]
In order to prevent such a trouble, the toner consumption amount prediction information may be corrected according to the characteristics of the image regarding the prediction of the toner consumption amount in the image forming apparatus.
[0108]
For example, the LUT 302 used for predicting the toner consumption in the image processing circuit in relation to the image characteristics such as whether the image data format is the JPEG format or the GIF format and whether or not the optimum process condition for the image characteristics is changed. May be changed to an optimum correction value.
[0109]
For example, both GIF format image data and text-only document data are suitable for printing in the resolution priority mode, but the GIF format also handles charts other than characters. The optimum process conditions are different from those of text document data that handles only characters. For example, if there is a difference between the toner consumption under the process conditions that make the character edge reproduction clear and print with easy-to-read text and the toner consumption under the process conditions in the GIF format, The correction data in the LUT 302 may be rewritten so that the toner consumption can be accurately predicted. In particular, since the ratio of the edge portion tends to increase in text data or the like, it is also effective to set a correction value that corrects the amount of toner consumed in the processing of the edge portion in the electrophotographic process.
[0110]
As described above, in the image processing circuit, the image processing for the image data is changed according to the characteristics of the image data to be printed, such as whether the image requires at least gradation or the resolution. In accordance with the image forming process conditions (parameters) of the image forming unit, the value of the predicted information of the toner consumption is corrected, so that appropriate image formation according to the characteristics of the image to be printed and Toner replenishment control is possible.
[0111]
In the present embodiment, an example of changing the process conditions (parameters) for charging, developing, and transfer has been described. Of course, other process conditions may be changed without departing from the spirit of the present invention.
[0112]
Further, the specific effects of this embodiment are as follows.
[0113]
Since the storage position of the data to be acquired is specified in the operation unit 6 of the image forming apparatus 1, image processing and image forming processing can be performed only by the image forming apparatus 1, no other client apparatus is required, and the image to be acquired Appropriate image processing and appropriate toner consumption prediction can be performed according to the data type.
[0114]
Since the storage location designation of the data to be acquired is performed in the operation unit 6 of the image forming apparatus 1, communication software can be simplified, and development of the software is facilitated.
[0115]
Since “Contents-type” is inquired of the server and the image format is determined based on the result, printing can be performed normally even when there is no URL extension.
[0116]
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described. In the following description, description of parts similar to those of the first embodiment will be omitted, and description will be made focusing on characteristic parts of the second embodiment.
[0117]
As a second embodiment, desired data is acquired by HTTP protocol based on a URL input by another device connected to the network 30, and image data is generated based on the acquired data to form an image. An image forming apparatus that performs the above will be described as an example.
[0118]
In the present embodiment, position information in which data to be acquired is stored is input as a URL from the client device 24 connected to the network 30, and the input URL information is transmitted to the image forming apparatus 1. The image forming apparatus 1 that has received it acquires data from the server 7 and forms an image.
[0119]
FIG. 5 is a block diagram showing the configuration of the entire network system including the image forming apparatus 1 according to the second embodiment. The same parts as those in FIG.
[0120]
In FIG. 5, reference numeral 24 denotes a client device, which has a function of designating data to be acquired and imaged by the image forming apparatus 1. Reference numeral 4a denotes an image processing circuit, which basically performs substantially the same function as that of the above-described image processing circuit 4. The configuration thereof will be described later with reference to FIG. Reference numeral 5a denotes a printer, and its configuration will be described in detail with reference to FIG.
[0121]
FIG. 6 is a block diagram showing the configuration of the image processing circuit 4a according to the second embodiment, and the same parts as those in FIG.
[0122]
In FIG. 6, 8 is a DMA data transfer circuit for controlling the DMA transfer of image data from the image memory 2, 25 is a gamma conversion circuit for performing gamma conversion, and 26 is a binary data obtained by binarizing input image data. Is a binarization circuit for generating 45 is an R data signal indicating the red component data of the image data, 46 is a G data signal indicating the green component data of the image data, 47 is a B data signal indicating the blue component data of the image data, and 48 is An R data signal converted by the gamma conversion circuit 25, 49 a G data signal converted by the gamma conversion circuit 25, and 50 a B data signal converted by the gamma conversion circuit 25. 39 is a color selection signal for selecting a color for image formation, 51 is a binarization method selection signal for selecting a binarization method in the binarization circuit 26, 52 is an LED for controlling the lighting of the LED array It is a drive signal.
[0123]
The DMA data transfer circuit 8 is connected to the system bus 30 and is controlled by the CPU 101 that controls the entire image forming apparatus 1 via the system bus 30. When transferring the image data held in the image memory 2 by the DMA transfer by the DMA data transfer circuit 8 to the image processing circuit 4a, first, the CPU 101 transfers the R, G, and B images to the DMA data transfer circuit 8, respectively. The address of the image memory 2 in which the data is held and the size of the data to be transferred are set. Thereafter, the DMA data transfer circuit 8 synchronizes with the printing operation of the printer 5a from the image memory 2 by the DMA to perform R, G, The B image data are sequentially read, and the read data are output to the gamma conversion circuit 25 as an R data signal 45, a G data signal 46, and a B data signal 47. This output is performed in synchronization with the R, G and B data. That is, R, G, and B data for each pixel are output simultaneously.
[0124]
The R data signal 45, the G data signal 46, and the B data signal 47 thus input to the gamma conversion circuit 25 are gamma-converted based on a preset gamma conversion table, and the R data signal 45 to the R data signal 48, G A G data signal 49 from the data signal 46 and a B data signal 50 from the B data signal 47 are generated and output, respectively. The R data signal 48, G data signal 49, and B data signal 50 output from the gamma conversion circuit 25 are input to the binarization circuit 26. The binarization circuit 26 selects which color to output based on the color selection signal signal 39 and determines which binarization method to binarize based on the binarization method selection signal 51. decide. In the present embodiment, it is assumed that the binarization circuit 26 can select one of two binarization methods, a dither method and an error diffusion method.
[0125]
Here, the dither method is based on each luminance data and converts the luminance data into a binary pattern on the basis of a binarized pattern that expresses a density suitable for the luminance as an area gradation. Is a method for generating This dither method is a binarization method suitable for printing such as illustrations, drawings, characters, etc., in which there are few transitions in gradation and the boundaries of the regions are clear.
[0126]
On the other hand, the error diffusion method is based on the original data of the pixel to be binarized, the binarized original data of the surrounding pixels, the error between the data generated by the binarization, and the random number. This is a binarization method that performs pixel binarization, and is a binarization method suitable for natural images such as photographic data with many transitions in gradation.
[0127]
The binarized image data is output to the printer 5a as the LED drive signal 52.
[0128]
Further, the LED drive signal 52 is also sent to the integrator 303 as binarized image data, and is integrated by the integrator 303. Since the accumulator 303 is an area gradation based on binary data, it may be a simple up-counter. In that case, an accumulator with a smaller circuit is sufficient than in the case of PWM modulation. Further, integration is performed for each image data corresponding to each toner color, and the integration result is read by the CPU 101 and stored in the memory 102. The CPU 101 reads out the integration result stored for each toner color from the memory 102 and immediately notifies the CPU 202 of the printer 5a as toner consumption amount prediction data.
[0129]
FIG. 7 is a block diagram showing the structure of the printer 5a of this embodiment, and the parts common to those in FIG.
[0130]
In FIG. 7, 27 is an LED array in which each element emits light in response to the LED drive signal 52, 15 is a latent image formed by lighting each element of the LED array, and an image is formed by adsorbing toner to the latent image. A photosensitive drum 16 is a revolver that holds toner cartridges of C, M, Y, and K and rotates in accordance with the color to be developed. 17 is a C (cyan) toner cartridge, 18 is an M (magenta) toner cartridge, 19 is a Y (yellow) toner cartridge, 20 is a K (black) toner cartridge, and each cartridge is a toner as in the first embodiment. It consists of a bottle and a developing device. 21 is a transfer drum for attracting the paper and transferring the toner of the developing device onto the paper, 22 is a fixing drum for fixing the toner onto the paper, 23 is a supply drum for holding the paper and feeding the paper during image formation A paper cassette, 52 is an LED drive signal, and 44 is a paper transport path.
[0131]
The printer 5a is a printer that forms an image by an electrophotographic method, and forms a color image on a sheet with toners of four colors of C (cyan), M (magenta), Y (yellow), and K (black). . The image development is different from the laser method described above in that an LED array is used.
[0132]
When forming an image, first, the paper loaded in the paper feed cassette 23 is fed, and the paper is transported through the paper transport path 44 and is attracted to the transfer drum 21 and sticks to the surface of the transfer drum 21. The transfer drum 21 rotates at a constant speed, and the paper moves in accordance with the rotation of the transfer drum 21. When the printer 5 a performs printing, an LED drive signal 52 is supplied from the image processing circuit 4. The supplied LED drive signal 52 is one of C, M, Y, and K image signals generated by the binarization processing of the binarization circuit 26. First, the C image signal is input.
[0133]
In the LED array 12, LEDs are linearly arranged corresponding to the lateral width of the photosensitive drum 15, and one LED has a size corresponding to the lateral width of one pixel. At the stage where image data for one scanning line to be developed is supplied by the LED drive signal 52, a latent image for one scanning line is formed by light emission of the LED. The LED of the portion where the LED drive signal 52 is on is lit and the potential of the photosensitive drum 15 is high, and the portion of the LED drive signal 52 is not lit, and the potential of the photosensitive drum 15 is lowered to form a latent image.
[0134]
The latent image formed on the photosensitive drum 15 is first developed at a portion where the C toner cartridge 17 and the photosensitive drum 15 which are arranged in advance at the portion where the revolver 16 and the photosensitive drum 15 are in contact with each other. In contact with the negatively charged cyan toner stored in the developer coated on the developing sleeve. The cyan toner is developed by being attracted by an electric suction force only to a portion of the photosensitive drum irradiated with the laser. A portion of the photosensitive drum 15 where the toner is adsorbed moves to a portion in contact with the transfer drum 21 by the rotation of the photosensitive drum 15. In the portion where the transfer drum 21 and the photosensitive drum 15 are in contact, the toner adsorbed on the photosensitive drum 15 is transferred onto the paper adsorbed on the transfer drum 21.
[0135]
Thereafter, the revolver 16 is rotated by 1/4 of the entire circumference so that the M toner cartridge 18 contacts the photosensitive drum 15. Then, an M image signal is input to the laser drive signal 42, and magenta toner is transferred onto the paper in the same manner as the C development. In the development of each color, the color selection signal 39 is set so that C image data is output to the LED drive signal 52 during C development, and M, Y, K image data during M, Y, K development, respectively. Is output to the LED drive signal 52. Similarly, Y, K development is performed, and toners of C, M, Y, K colors are transferred onto the sheet adsorbed on the transfer drum 21.
[0136]
Thereafter, the sheet is separated from the transfer drum 21 and passes between the two fixing devices 22 through the sheet conveyance path 44. At this time, the toner image heated and pressurized by the fixing device 22 and transferred onto the paper is fixed on the paper and discharged out of the printer 5a. Printing is executed in this way,
When the printer 5 performs the printing operation as described above, the toner in the developing device is consumed. Therefore, in the two-component development method including the toner and the magnetic carrier, the toner density is appropriately set so as to maintain an appropriate toner density. It is necessary to perform toner replenishment control for replenishing consumed toner into the developing device.
[0137]
Therefore, based on the toner consumption amount prediction information for each toner color notified from the CPU 101 to the CPU 202 of the printer 5a during the printing operation, the CPU 202 performs C, M, Y, K toner cartridges 17, 18, 19, Control is performed so that toner is replenished from the 20 toner bottles into each toner color developer.
[0138]
FIG. 8 is a flowchart showing processing in the image forming apparatus 1 according to the second embodiment, and a control program for executing this processing is stored in the memory 102.
[0139]
As illustrated in FIG. 5, the image forming apparatus 1 according to the second exemplary embodiment is connected to the client apparatus 24 via the network 32. The client device 24 is a data processing device capable of inputting a character string by a user such as a personal computer. In the client device 24, the user inputs data indicating data to be printed by the image forming apparatus 1. The format of this data is URL as in the first embodiment.
[0140]
The user of the client device 24 inputs this URL, and then transmits the input URL to the image forming apparatus 1 via the network 30. The URL transmitted in this way is received by the image forming apparatus 1 via the network 32 and the network interface 3. Until this input is made, the image forming apparatus 1 waits for input (step S21). When a URL is input in step S21, the process proceeds to step S22, where the structure of the input URL is analyzed, and the address of the server holding the desired data and the position of the data to be acquired in the server are determined. Identify. Here, it is assumed that there is data to be acquired in the server 7.
[0141]
In step S23, a GET command for the data to be acquired is issued to the server 7. This GET command is issued to the server 7 via the network interface 3 and the network 32.
[0142]
As a result, the server 7 transmits the data designated by the GET command to the image forming apparatus 1 via the network 32 and the network interface 3.
[0143]
When the reply from the server 7 is received in this way, the process proceeds from step S24 to step S25, and image data is generated in the image memory 2 based on the data received from the server 7. In step S26, it is determined whether the extension of the URL analyzed in step S22 indicates a JPEG image such as “, JPG” or “.jpeg”.
[0144]
If it is a JPEG image, the process proceeds to step S27 to set image processing for the JPEG image in the image processing circuit 4a. That is, the gamma conversion circuit 9 sets a gamma table for natural images, and the binarization circuit 10 sets a binarization method using an error diffusion method.
[0145]
Furthermore, based on the URL extension information analyzed in step S22, if the image is a JPEG image, the CPU 101 notifies the CPU 202 that the image is in the JPEG format with priority on gradation. In the CPU 202, when a corresponding image is printed, process conditions (parameters) giving priority to gradation are set in the image forming unit.
[0146]
On the other hand, when it is determined in step S26 that the image is not a JPEG image, the process proceeds to step S29, and the setting for the GIF image is performed on the image processing circuit 4a. That is, the gamma conversion circuit 9 sets an illustration gamma conversion table, and the binarization circuit 10 sets a dithering binarization method.
[0147]
After image processing and binarization processing are executed in step S27 or step S29 in this way, the process proceeds to step S28, and image formation based on the image processing and binarized image data is executed by the printer 5a. In addition, image data that has been binarized by an error diffusion method for a JPEG image and a dither method for a GIF image is integrated by an integrator for each toner color, and the integration result is notified to the printer 5 as toner consumption amount prediction information. .
[0148]
In this way, the image forming process based on the data stored on the server 7 designated by the client device 24 is completed.
[0149]
According to the processing described above, the JPEG image is subjected to gamma conversion for natural images and further binarized by the error diffusion method, so that an image is formed with a color and binarization suitable for natural images. Is possible.
[0150]
Further, gamma conversion for illustration is performed on the GIF image and further binarized by a dither method, so that it is possible to form an image with a color and binarization suitable for illustration.
[0151]
However, both are converted into binary data, and in printers at a low cost, the binary data is integrated to add up the number of dots. As it is proportional to the number of dots, the integration circuit can be simplified.
[0152]
Further, as described above, in the present embodiment, whether the data format of the image to be printed is JPEG format or GIF format is determined based on the extension of the image file included in the URL, and according to the determination result. The communication means 201 notifies the CPU 202 of the printer unit from the CPU 101. On the engine side, a printing operation is performed by setting process conditions according to the data format. Specifically, an optimal reproduced image can be obtained by switching each process condition (parameter) for image formation as in the first embodiment.
[0153]
The parameter to be switched may be at least one of a charging voltage, a developing bias, and a transfer voltage, as in the first embodiment. Further, for example, in an apparatus using a high voltage power source that performs constant current control, the current value may be switched.
[0154]
As described above, according to the present embodiment, the JPEG image is formed by performing image processing suitable for printing a natural image such as a photograph, and the GIF image is suitable for printing an illustration or the like. Even when the image processing is performed and the image is formed and the area gradation method is used, the toner consumption amount information is notified to the printer unit, and appropriate process condition (parameter) setting and appropriate toner replenishment control can be performed. .
[0155]
Further, effects specific to the second embodiment are as follows.
[0156]
In the client apparatus, an address at which desired data is stored can be specified. In the image forming apparatus 1, an operation unit for specifying the address is not necessary, and the cost can be reduced.
[0157]
An appropriate binarization process according to the type of image is possible.
[0158]
Since the type of the image is determined by the extension of the URL, the present invention can be applied to protocols other than the HTTP protocol.
[0159]
As described above, both the first and second embodiments are configured such that the image processing unit predicts the toner consumption amount from the image data and notifies the printer unit, so that the printer can be used regardless of the configuration of the image forming unit. The toner replenishment control can be made substantially the same, and even if the image forming apparatus is configured such that various image processing boards are connected to the printer unit, there is no need to significantly change the control of the printer unit. There is an advantage.
[0160]
In this way, even when a flexible image processing board capable of various image processing is used according to the cost and function desired by the user, there is no new cost increase in the printer unit, and the design of the printer unit is common. Therefore, there is an advantage that the development period of the printer unit can be shortened and the printer unit can be easily shared.
[0161]
In addition, even if there are various combinations of various image data from the network and image forming apparatuses that perform printing, there is an advantage that appropriate process condition setting and proper toner replenishment control can be performed.
[0162]
[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described. In the following description, description of parts similar to those of the second embodiment will be omitted, and description will be made focusing on characteristic parts of the third embodiment.
[0163]
As described above, when the process conditions are automatically set on the image forming apparatus side, the image processing unit performs the extraction process for extracting the characteristics of the image data to be printed, and the extracted image characteristics are used. In general, the image type is determined, and the process condition in the apparatus is set to an optimum condition.
[0164]
However, in such a configuration, it is necessary to perform the feature extraction processing of the image data before actually printing, so it takes time to set the image forming conditions, and the time to actually start the printing operation. As a result, the problem arises that the throughput decreases.
[0165]
The present embodiment provides an image forming apparatus capable of shortening the waiting time until the start of the printing operation and setting process conditions suitable for an image to be printed without interrupting the printing operation.
[0166]
Hereinafter, processing in the image forming apparatus of this embodiment will be described. The processing of the image forming apparatus of the present embodiment is obtained by changing a part of the processing of the image forming apparatus of the second embodiment, and will be described with reference to the flowchart of FIG.
[0167]
In the second embodiment, the extension of the URL analyzed in step S22 is not used until step S26, but in this embodiment, the format of the image file to be printed is “, JPG” or “.jpeg” in step S22. Whether the image is a JPEG image such as “” is determined based on the extension of the image file.
[0168]
Further, in step S22, the CPU 101 notifies the CPU 202 of the printer unit from the CPU 101 whether the image data to be printed is in JPEG format or GIF format. Upon receiving this, the engine side performs a predetermined operation in advance so that the process conditions can be set in a short time according to the data format.
[0169]
This predetermined operation includes, for example, a preliminary operation such as a charging operation in which the surface potential of the photosensitive drum 15 becomes a predetermined surface potential and a cleaning operation for cleaning unnecessary toner on the photosensitive drum 15.
[0170]
Further, as a predetermined operation, a calibration operation for correcting gradation reproduction of the image forming unit may be performed.
[0171]
For example, the calibration operation is performed so that the gradation reproducibility of the printer is appropriate so that the operation is performed in the gradation priority mode when the JPEG format is used. Then, when the image processing unit generates image data through steps S23, S24, and S25 and both the image processing unit and the printer unit are ready for printing, the image subjected to JPEG image processing in step S27. Data can be transmitted to the printer unit, and a printing operation can be performed under the process conditions in the gradation priority mode to obtain a reproduced image suitable for the data format.
[0172]
On the other hand, a calibration operation is performed so that the resolution of the printer is appropriate so that the printer operates in the resolution priority mode when it is in the GIF format. In this case, since the tone reproducibility is not the highest priority, a simple calibration operation that can be performed in a short time may be performed, or the calibration operation itself may not be performed. Then, when the image processing unit generates image data through steps S23, S24, and S25 and both the image processing unit and the printer unit are ready to print, the image subjected to the GIF image processing in step S27. Data can be transmitted to the printer unit, and a printing operation can be performed under the process conditions in the resolution priority mode to obtain a reproduced image suitable for the data format.
[0173]
[Other Embodiments]
In the above description, the first to third embodiments have been described independently. However, the present invention is not limited to this, and the features of one or more embodiments may be combined. For example, the printer 5a of the second embodiment may be employed in the first embodiment. Further, the image processing circuit 4 of the first embodiment may further include the function of the image processing circuit 4a of the second embodiment, and the image processing circuits 4 and 4a are both shown in FIGS. Not all of the illustrated image processing functions but only a part thereof may be provided.
[0174]
In the first embodiment, the type of the image data is determined based on the format information from the server, the UCR process is performed on the image data according to the type of the image data, and the C, The multivalued image data of M, Y, and K is accumulated by the accumulator 301 after the data corrected through the LUT 302. As described in the second embodiment, the image data is discriminated based on the URL extension. Needless to say, the present invention can also be applied to the case of PWM modulation using multi-value image data in the image processing circuit of the first embodiment.
[0175]
As described above, in the image processing circuit of the first embodiment, when the type of image is determined based on the URL extension, for example, by switching the image processing to an appropriate one depending on whether it is a JPEG image or a GIF image, It is possible to appropriately select gradation priority or resolution priority.
[0176]
That is, if it is determined as a JPEG image by the extension of URL, gradation priority processing is selected, PWM modulation with a frequency half that of the clock signal is performed, and image data integration also includes correction data when gradation priority is given. The image is selected by the LUT 302, integrated by the integrator 301, the integration result is notified to the printer 5, and process conditions (parameters) giving priority to gradation regarding image formation are set in the image forming means.
[0177]
If the image is determined to be a GIF image, resolution priority processing is selected, PWM modulation is performed at the cycle of the clock signal, and resolution data priority correction data is selected by the LUT 302 and integrated by the integrator 301. The result is notified to the printer unit 5, and process conditions (parameters) giving priority to resolution for image formation are set in the image forming means.
[0178]
As described above, since the appropriate image processing is selected by the extension of the URL, and the image data integration processing is also appropriately corrected, the toner consumption amount can be predicted well, and the printer unit 5 can perform the proper correction. Can maintain a high toner density. At the same time, with regard to image formation, it is possible to set an image forming unit with more suitable process conditions that give priority to either gradation or resolution depending on the format of image data to be printed, thereby enabling image formation suitable for the image. To do.
[0179]
Note that the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or a device (for example, a copier, a facsimile device, etc.) including a single device. You may apply to.
[0180]
Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. This can also be achieved by reading and executing the program code stored in.
[0181]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
[0182]
As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
[0183]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. A case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.
[0184]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0185]
When the present invention is applied to the above-described storage medium, the storage medium stores program codes corresponding to the flowcharts described above (shown in FIGS. 4 and / or 8).
[0186]
【The invention's effect】
As described above, according to the present invention, the main image processing functions can be integrated into the image processing board as the image processing means, and an image processing board having a flexible configuration capable of performing various image processing is formed. Even when used in an apparatus, it is possible to set appropriate image forming conditions based on image data, and to perform an image printing operation suitable for the type of image to be printed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a system including an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of an image processing circuit according to the first embodiment.
FIG. 3 is a block diagram illustrating a configuration of a printer according to the first embodiment.
FIG. 4 is a flowchart illustrating processing in the image forming apparatus according to the first embodiment.
FIG. 5 is a block diagram showing a system configuration including an image forming apparatus according to a second embodiment of the present invention.
FIG. 6 is a block diagram illustrating a configuration of an image processing circuit according to a second embodiment.
FIG. 7 is a block diagram illustrating a configuration of a printer according to a second embodiment.
FIG. 8 is a flowchart illustrating processing in the image forming apparatus according to the second embodiment.

Claims (1)

Storage means for storing image data;
Image processing means for executing image processing on the image data stored in the storage means;
An image forming apparatus Ru comprising an image forming means, a to form an image using a developer based on the image data subjected to image processing by the image processing means,
Said image processing unit performs image processing that differs depending on the type of image to the image data, and notifies the type of the image on the image forming means,
The image forming unit forms an image based on the image data image-processed by the image processing unit after performing a calibration operation according to the notified type of the image. .

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