JPH086329A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device eliminating the wasteful image formation for a blank document, preventing a waste of the paper, toner, and time, and easy to use. CONSTITUTION:A page memory 12 and an image data detecting circuit 13 are connected to a CCD line image sensor 9 converting the reflected light of a read document into an electrical signal. The electrical signal converted by the line image sensor 9 is inputted to the page memory 12 and also to the detecting circuit 13. When the detecting circuit 13 judges that the read document has an image, the transfer paper is fed from a paper feed section 41, and the image data stored in the page memory 12 are fed to an image processor 20 to start a copying action. When the detecting circuit 13 judges that there is no image, no paper is fed, and no data is outputted to the image processor 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a facsimile.

[0002]

2. Description of the Related Art Recently, an image forming apparatus such as a copying machine equipped with an automatic document feeder has been increasing. An automatic document feeder (hereinafter referred to as an ADF) separates a plurality of documents placed on a document table one by one and conveys them to an image reading position of an image forming apparatus, and the reading (exposure) ends. The original is ejected outside the machine. In addition, recently, an ADF having a document reversing function that enables the reading of double-sided documents has also been generalized.

[0003]

By the way, when setting a document on the ADF, which direction should the document be set, that is, whether the face on which image formation is desired should be faced up or faced down? Sometimes it's hard to tell if you're setting it up. In particular, for example, AD in the same office
When there are a copying machine with F and a facsimile and the originals are set in different directions, the originals are often set in the wrong direction. If you start the operation as a copying machine or a facsimile with the originals set in the wrong orientation, the blank page on the back of the originals or unnecessary images may be copied or faxed, and the paper, toner, power, etc. There was a problem of wasting. Of course, in order to form an image correctly, it is necessary to set the original again (correct the orientation of the original) and perform the image forming operation again.

Further, in the conventional image forming apparatus, when the start of the image forming operation is instructed, the image forming operation is faithfully executed even for a blank original. Therefore, there is a problem that the user does not notice that the blank document is mixed and the document contains useless blank paper. Then, when a single-sided original is mixed in the double-sided original, the image forming operation is performed on the white paper on the back of the single-sided original, and toner or the like may adhere to the background to cause stains. There is also.

Further, since the image forming operation is performed on the blank sheet document, the unnecessary fixing operation is performed on the recording sheet corresponding to the blank sheet. When the fixing operation is performed, the paper takes heat and the temperature of the fixing roller decreases. Then, since the heater generates heat to maintain the surface temperature of the fixing roller, there is a problem of wasting energy.

The present invention solves the above-mentioned problems in an image forming apparatus equipped with a conventional automatic document feeder, and
An object of the present invention is to provide an image forming apparatus that prevents waste of toner and time and is easy to use.

[0007]

According to the present invention, there is provided an automatic document feeder having a document reversing function,
Image reading means for reading the image of the original on the contact glass, storage means for storing the image data of the original read by the image reading means, and image formation based on the image data stored in the storage means An image forming section for transferring the formed image onto a recording sheet, a sheet feeding section for feeding the recording sheet to the image forming section, a fixing section for fixing the unfixed image transferred on the recording sheet, and a recording sheet In an image forming apparatus having a recording paper reversing mechanism including a double-sided unit that stocks recording paper on one side of which image formation is possible on both sides, a document read by the image reading means is provided. Image data detection means for detecting the presence or absence of an image is provided, and when the image data detection means detects the presence of a document image, the paper feeding means starts feeding. Both are solved by providing a control means for controlling so as to enable image formation by the image forming section reads out the image data stored in the storage means.

In order to solve the above-mentioned problems, the present invention reads the original image on the contact glass by the image reading means, inputs the read image data into the storage means, and inputs the read image data. It is proposed that the image data detecting means detects whether or not there is an image in the image data.

Further, according to the present invention, in order to solve the above-mentioned problems, when the image data detecting means detects the absence of an image of a document fed by the automatic document feeder,
It is proposed that the document is inverted by the document reversing function of the automatic document feeder and read again by the image reading means.

Further, according to the present invention, in order to solve the above-mentioned problems, when the image data detecting means detects that there is no image on both sides of the document fed by the automatic document feeding device, the document is detected as above. It is proposed to eject the paper from the automatic document feeder.

Further, in order to solve the above-mentioned problems, the present invention provides a paper transport path for discharging the recording paper in the double-sided unit without passing through the image forming section, and selects a selected copy mode and It is proposed to automatically select a sheet conveyance path that does not pass through the image forming section or a sheet conveyance path that leads to the image forming section according to the detection result of the image data detecting means.

Further, according to the present invention, in order to solve the above-mentioned problems, a recording sheet in the double-sided unit can be discharged without passing through the fixing means in a sheet conveying path that does not pass through the image forming section. To propose.

[0013]

When the original on the contact glass is read by the image reading means, the image data detecting means detects the presence or absence of an image on the original. Then, after it is detected that the original image is present, the recording paper is fed from the paper feeding means, and the image data is read from the storage means to form an image. Therefore, since the recording paper is not fed and the image is not formed until the original image is detected, the wasteful image formation is not performed on the original without the image, that is, the blank original or the original with the wrong front and back. .

Other functions will be apparent from the description of the embodiments below.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing the main body of a copying machine according to an embodiment of the present invention. The ADF 200 shown in FIG. 2 is mounted on the upper part of this copying machine. First,
The description begins with the body of the copier.

The main body 50 of the copying machine shown in FIG. 1 comprises a scanner section 100 and a printer section 300. A contact glass 1 is arranged on the upper surface of the scanner unit 100, and a light source 2, first to fifth mirrors 3, 4, 5, are provided below the contact glass 1.
6, 7, a lens 8, a line image sensor 9 and the like are arranged. The light source 2 and the first mirror 3 are attached to the first traveling body 10, and the second and third mirrors 4 and 5 are attached to the second traveling body 11, respectively, in parallel with the contact glass 1 in the document scanning direction (sub-direction). It is movable in the scanning direction). The movements of the first traveling body 10 and the second traveling body 11 are interlocked with each other, and the second traveling body 11 moves in the same direction at a speed half that of the first traveling body 10.

The light source 2 illuminates the original through the contact glass 1, and the reflected light from the original image is deflected by the first mirror 3. Further, the reflected light is reflected by the second to fifth mirrors 4,
The light is reflected by the lenses 5, 6 and 7, passes through the lens 8 and enters the line image sensor 9. In this way, the reflected light from the original image is finally formed on the light receiving surface of the line image sensor 9. The original image is scanned in the sub-scanning direction by the movement of the first and second traveling bodies 10 and 11. In the present embodiment, the image reading resolution is 16 dots /
It is set to mm and can read A3 size documents. Therefore, the line image sensor 9 has 5000
A pixel CCD line image sensor is used.

The page memory 12 and the image data detection circuit 13 are included in the scanner section 100 and are connected to the line image sensor 9, respectively. The page memory 12 is a memory that stores the electric signal converted by the line image sensor 9. An image data detection circuit (hereinafter, referred to as a detection circuit) 13 is a circuit that detects whether or not the read document has image data, and determines the presence or absence of an image based on the output level of the line image sensor 9.
The electric signal converted by the line image sensor 9 is input to the page memory 12 and the detection circuit 13 at the same time. When the detection circuit 13 determines that there is image data, the image data stored in the page memory 12 is sent to the image processor 20.

Conventionally, a copying machine or the like has been proposed which detects the presence or absence of a document image, that is, a blank sheet by performing a prescan before scanning a document for image formation, and detecting a blank sheet. In the machine, it is not necessary to perform prescan to detect the presence or absence of the original image, and
The detection circuit 13 detects the presence / absence of image data (presence / absence of a document image) of the data to be stored in the page memory 12,
When the detection circuit 13 detects the presence of an image, the page memory 12
Since the image data stored in is output, blank sheet detection can be performed while reading the image data, and blank sheet detection can be performed more accurately than in the case of performing image formation.

The image processor 20 performs image processing such as scaling based on a key input from an operation panel (not shown). The image signal processed here is applied to the semiconductor laser 31, and the semiconductor laser 31 converts the image signal into an optical signal and performs writing scanning on the photoconductor 35. That is,
The laser light emitted from the semiconductor laser 31 is the polygon mirror 3
2, the photoconductor 35 through the fθ lens 33 and the mirror 34
Incident on. In the present embodiment, the photoconductor 35 is composed of an organic photoconductor (OPC) having a spectral sensitivity to semiconductor laser light, and image formation is performed by a conventionally well-known electrophotographic method.

Around the photosensitive member 35, a charging charger 36, a developing unit 38, a transfer charger 39, a cleaning unit 40 and the like necessary for the electrophotographic process are arranged. Reference numeral 37 is a laser beam irradiation unit. Further, a paper feed unit 41 is provided on the right side of the photoconductor 35, and a paper discharge unit 43 is provided on the left side of the photoconductor 35.
0 is formed. Further, a fixing unit 42 is provided on the downstream side of the transfer charger 39. Then, the paper output unit 43
A double-sided tray 45 is attached below the
Reference numeral 5 is connected to the transfer paper transporting path 70 by the transfer paper transporting path 71. Incidentally, reference numerals 44 and 46 are switching claws for switching the transfer sheet transporting path.

The electrostatic latent image formed on the photoconductor 35 is visualized as a toner image by the developing unit 38, and the toner image is transferred onto the transfer paper sent from the paper feeding section 41. When the transfer paper passes through the fixing unit 42, the toner image on the transfer paper is fixed on the transfer paper. Then, the transfer paper is ejected to the paper ejection unit 43 to complete the hard copy.

In the case of double-sided copying, the transfer claw 44 is switched to transfer the transfer paper from the fixing section 42 to the double-sided tray 4.
Lead to 5 and stock once. The transfer paper stocked in the double-sided tray 45 is sent again to the transfer paper transfer path 70 from the transfer paper transfer path 71a, the image is transferred and fixed on the back side, and the paper is discharged to the paper output unit 43. In the copying machine of this embodiment, the transfer paper stocked in the double-sided tray 45 may be discharged to the paper discharge section 43 via the transfer paper transport path 71b without being copied to the back side. It is possible. At this time, the fixing operation is not performed on the transfer sheet.

Next, A mounted on the main body 50 of the copying machine
The DF will be described.

The ADF 200 shown in FIG. 2 has a separation sheet feeding section on the left side, a conveyance section in the center, and a sheet discharging / discharging section on the right side in this figure.
The inversion part is located.

In the ADF 200, reference numeral 201 is a document table, and 217 is a document ejection section. Then, in the separation sheet feeding section, the document set sensor 202 and the pinch roller 20 are provided.
3, calling roller 204, separation belt 205, separation roller 206, registration sensor 2 also serving as a document width size sensor
07 etc. are arranged. The transport drive roller 20 is provided in the transport unit.
8 and the driven belt 209 that is stretched over the driven roller 209
10 are arranged. A document guide 21 is provided in the paper output / reversal section.
1, a reversal driven roller 212, a reversal switching claw 214, a reversal roller 215, a paper ejection roller 216, and the like are arranged. Note that reference numeral 1
4 is a document stop claw provided on the main body of the copying machine,
The tip (the left end in the figure) can be moved to a position protruding from the contact glass 1 and a retracted position.

When the original is set on the original table 201 and is inserted into the separation / feeding unit until it is slightly abutted, the original set sensor 202 detects the original. When a start button (not shown) of the copying machine is pressed in this state, the pinch roller 203 descends and the original is sandwiched together with the calling roller 204. After that, when a motor (not shown) starts to rotate, the calling roller 204 is driven to start feeding the document. When there are a plurality of called originals, the lowest original is separated into one sheet by the separation belt 205 and the separation roller 206, is fed, and is sent to the conveyance section. In the transport section, the document is contact glass 1 by the transport belt 210.
Is transported over.

When a one-sided original is used, the leading edge of the original is the stop claw 1.
Immediately after hitting 4, the conveyor belt 210 is stopped,
The document is stopped. Then, the document reading (exposure) by the scanner unit 100 described above is performed. Thereafter, when a document replacement signal is sent from the copying machine body side, the rotation of the conveyor belt 210 is restarted and the stop claw 14
Moves to the retracted position and sends the document to the paper output / reversal unit. At this time, the next original is also fed. The document that has entered the paper discharge / reversal unit is discharged to the document discharge unit 217 by the reverse roller 215, the paper discharge roller 216, and the like.

In the original setting method for a single-sided original, the side to be copied (front side) is set up, that is, the image side is set up on the original table 201. At this time, the plurality of originals are sequentially arranged in page order, that is, with the first page facing up.
Therefore, the last page is at the bottom, and the original is fed from the last page. Then, the document discharge section 217
The originals ejected in are arranged in page order with the side to be copied facing up.

In the original setting method for a double-sided original, the original surface is faced up and the originals are set in page order. The document is fed from the lowest document, but in the case of a double-sided document, the final page side is facing upward when the document is conveyed onto the contact glass 1. Therefore, when the exposure is performed as it is and copying is performed, the copied documents are not arranged in the page order. Therefore, in the case of a double-sided original, the original sent from the separating / feeding unit to the conveying unit is sent to the paper output / reversing unit as it is, and the reversal switching claw 214 is switched to a reversal position (not shown) to reverse the original. It rotates around the roller 215 and is returned to the exposure position on the contact glass 1. Then, since the final page faces downward, exposure is performed in this state. Then, the original is sent again to the paper output / reversing unit, goes around the reversing roller 215, and is returned to the exposure position on the contact glass 1 again. Then, the page before the last page faces downward, and the exposure is performed in this state. Then, the document is sent to the paper discharge / reversal unit three times, this time the reversal switching claw 214 is switched to the position shown, and the document is discharged to the discharge unit 217. When a double-sided original is read, such an operation is repeated, and the read originals are stocked in the original discharge section 217 in page order. At this time, the back side of the document faces downward.

FIG. 3 is a block diagram showing the control system of the copying machine of this embodiment. As shown in this figure, the operation unit (operation panel) 130, the ADF 200, the scanner unit 100, and the main body drive unit 120 are controlled by the control unit 110. A motor for driving various input keys such as the mode selection key 131 of the operation unit 130, the ADF 200, the image detection circuit 13 of the scanner unit 100, or the switching claws 44 and 46 of the main body drive unit and the transfer paper conveying unit such as the duplex unit 45. Alternatively, a solenoid (not shown) or the like is connected to the I / O port (input / output port) 112 of the control unit 110. Each of these elements includes a CPU 11 of the control unit 110.
A control signal is output from 1 through the I / O port 112.

By the way, in the copying machine of this embodiment,
When the original is a blank original, it is possible to select the blank detection mode in which the copy operation is not performed on the blank surface.
Regarding the control in the blank sheet detection mode,
The case where the F200 is used will be described as an example. If the blank sheet detection mode is not designated, the copy operation is performed on the blank sheet document as in the conventional copying machine.

First, the case of a mode for copying a single-sided original or a double-sided original on one side of a transfer sheet will be described with reference to the flowchart of FIG. 4 and FIGS. When these two modes are designated from the operation panel 130 of the copying machine, FIG.
The control shown in the flowchart of FIG. That is,
A manuscript is set on the manuscript table 201 of the ADF 200 (step 1, hereinafter step is abbreviated as S), and the copy mode is selected by the mode selection key 131 of the operation panel 130 (S2). Then, a start button (not shown) is pressed to instruct copy start (S3). Then, the ADF 200 starts feeding the document (S4). Next, the CPU 111 of the control unit 110 determines whether or not the selected copy mode is the blank sheet detection mode (S
5). If it is not the blank sheet detection mode, a normal copy operation is performed (S5-1) and the process proceeds to S11. When the blank sheet detection mode is selected, it is determined whether the one-sided original is copied on one side of the transfer sheet and the one-sided → single-sided mode is selected (S
6). 1-sided ⇒ When not in 1-sided mode, that is, 2-sided original ⇒
The case of the single-sided mode will be described later. Single-sided ⇒ When the single-sided mode is selected, the scanner unit 1
Checked by the output of the image detection circuit 13 of 00 (S
7). Then, it is determined whether or not there is an image (S8), and if there is an image, a copy operation is performed (S9). After that, the transfer paper is discharged from the copying machine main body 50 (S10), and the document is AD
The sheet is discharged to the discharge section 217 of F200 (S11). next,
It is determined whether or not any document remains in the document table 201 of the ADF 200 (S12), and if there is no document, the operation ends. If the original remains, the operations from S4 onward are repeated. If the original image is not detected in S8, the original is sent to the paper output / reversing unit to be inverted, and the image on the back of the original is checked (S8-1) to determine whether or not there is an image on the back of the original. Yes (S8-2). If there is no image on the back side of the document, the copy operation is not performed and the process proceeds to S11. If there is an image on the back of the document, copy the image (S8
-3) Proceed to S10.

On the other hand, in the mode in which the two-sided original is copied on one side of each of the two transfer sheets, the process proceeds from S6 to S6-1, and the original is sent to the paper output / reversing section to be inverted (as described above). If the original is a two-sided original, read the back side first) and check the image on the back side of the original. Then, it is determined whether or not there is an image on the back surface of the document (S6-2), and if there is an image, a copy operation is performed (S6-3) and the transfer sheet is ejected (S6).
-4). Next, the original is sent again to the paper output / reversing section to be inverted and the image on the surface of the original is checked (S6-5).
If there is no image on the back side of the document in S6-2, the document is inverted without performing the copy operation, and the image on the front side of the document is checked (S6-5). Then, it is determined whether or not there is an image on the front surface of the document (S6-6), and if there is an image, a copy operation is performed (S6-7) and the process proceeds to S10. If there is no image on the front surface of the original, the process proceeds to S11 without performing the copy operation.

Here, the operation when a blank original is mixed in a plurality of single-sided originals will be verified. If the blank sheet detection mode and the single-sided → single-sided mode are selected, the process proceeds through S5 and S6, and then proceeds to S7. Since there is no image on the front side of the blank original document, the process advances from S8 to S8-1, and since there is no image on the back side of the original document, the process advances from S8-2 to S11 to eject the original document. Therefore, the copy operation is not performed on the blank document.

When a plurality of single-sided originals are mixed with the wrong side, the blank sheet detection mode and the single-sided → single-sided mode are selected, and the process proceeds through S5 and S6 and proceeds to S7. Since there is no image on the front side of the original for the original with the wrong front and back, the process proceeds from S8 to S8-1. Since there is an image on the back surface (original front surface) of the original, the process proceeds to S8-3, the copy operation is performed, and the transfer paper is ejected (S10). Therefore, if the front side and the back side of the original are mistaken, the copy operation is not performed on the blank paper on the back side, and the original is automatically turned over and copied. Therefore, it is possible to save the user the trouble of resetting the document and performing the copy operation again.

Further, in the mode of copying a double-sided original onto one surface of two transfer sheets, the operation when a blank original is mixed in the double-sided original will be verified. If the blank sheet detection mode is selected and the single-sided → single-sided mode is not selected, the process proceeds from S6 to S6-1. Since there is no image on the back of a blank document, S6
-2 to S6-5, and since there is no image on the front side, the process proceeds from S6-6 to S11, and the blank document is discharged. Therefore, the copy operation is not performed on the blank document.

If a single-sided original is mixed in the double-sided original in the mode for copying the double-sided original onto one side of two sheets of transfer paper, if the blank sheet detection mode is selected and the single-sided → single-sided mode is not selected, The process proceeds from S6 to S6-1. When a mixed one-sided original is set face up, there is no image on the back of the original, so the process proceeds from S6-2 to S6-5.
Then, the copy operation is performed on the front surface of the original to eject the transfer paper (S10). On the contrary, when the mixed one-sided original is set downward, there is an image on the back side of the original, so the copy operation is performed on the back side of the original and the transfer paper is ejected (S6-
3, 6-4). And since there is no image on the front side of the document,
The process proceeds from S6-6 to S11, and the document is discharged. Therefore, when the one-sided original is mixed in the two-sided original, the blank side is not copied and only the side with the image is copied.

As described above, when a plurality of one-sided originals include blank originals or originals with wrong front and back sides, and among a plurality of double-sided originals, there are blank originals on both sides or single-sided originals. If it does, the copy operation is not performed on the blank surface, and the original is automatically turned over to check the existence of the image and the copy operation is performed. Therefore, the blank copy is not performed, and the power and time are wasted. There is nothing to do. Further, it is possible to save the trouble of resetting the original and performing the copy operation again.

Next, the case of a mode for copying a single-sided original and a double-sided original on both sides of a transfer sheet will be described with reference to the flowcharts of FIGS. 5 and 6 and FIGS. Note that FIG.
The flowchart of FIG. 6 and the flowchart of FIG. 6 are connected by the connector A. When these two modes are designated from the operation panel 130 of the copying machine, the control shown in the flowcharts of FIGS. That is, the original is set on the original table (S1), and the copy mode is selected (S2). Then, the copy start is instructed (S
3) Then, the feeding of the original is started (S4). Next, it is determined whether or not the blank sheet detection mode is set (S5). If it is not the blank sheet detection mode, normal copy operation is performed (S5-
1), the process proceeds to S16. When the blank sheet detection mode is selected, it is determined whether the double-sided original is copied to both sides (front and back) of the transfer sheet, that is, double-sided → double-sided mode (S6). If the mode is not double-sided → double-sided mode, that is, a mode in which a plurality of single-sided originals are copied onto both sides of transfer paper, it will be described later.

Double-sided ⇒ When the double-sided mode is selected,
The original is sent to the paper output / reversal unit and inverted (when the original is a double-sided original, the back side is read first), and the image on the back side of the original is checked (S7). Then, it is determined whether or not there is an image (S
8) If there is an image, copy operation is performed (S9). The transfer paper on which the back side of the original has been copied is conveyed to the duplex unit 45 and stocked (S10). Then, the original is sent again to the paper output / reversing section to be inverted and the image on the front side of the original is checked (S11). However, if there is no image on the back side of the original in S8, the original is inverted without performing the copy operation and the front side of the original is checked. The image is checked (S11). Then, it is determined whether or not there is an image on the front surface of the document (S12), and if there is an image, it is determined whether or not transfer sheets are stocked in the duplex unit (S13). If there is a transfer sheet in the duplex unit, the transfer sheet is fed to copy the image on the front side of the document (S14). Then, the transfer paper is discharged to the paper discharge unit 43 (S
15) Do. This means that the images on the front and back of the original have been copied on both sides of the transfer paper. If there is no transfer paper in the duplex unit, the transfer paper is fed from the paper feed cassette 41 to copy the image on the front surface of the document (S13-1), and the transfer paper is ejected from the paper ejection unit 4
It discharges to 3 (S15). After that, the document is discharged from the ADF 200 (S16). Even if there is no image on the front surface of the document in S12, it is determined whether or not the transfer paper is stocked in the duplex unit (S12-1). in this case,
The copying operation is not performed on the transfer paper in the duplex unit, and the transfer paper is not passed through the fixing unit 42 (S12
-2) Discharge (S15). If there is no image on the front surface of the document and there is no transfer sheet in the duplex unit, the process proceeds to S16 and the document is discharged. Then, it is determined whether or not any document remains on the document table (S17), and if there is any document, the process proceeds to S4 to feed the next document and repeat the above operation. If no document remains on the document table, it is determined whether transfer paper is present in the duplex unit (S18). If there is no transfer paper in the duplex unit, the process ends. If there is transfer paper in the duplex unit, the transfer paper is set in the fixing unit 4.
2 is not passed through (S19) and discharged (S20), and the process ends.

On the other hand, in the mode in which a plurality of single-sided originals are copied on both sides of the transfer paper, the image on the surface of the original is checked (S6-1) and it is determined whether or not there is an image on the original surface (S6). -2). If there is an image on the front side of the document, it is determined whether or not there is a transfer sheet in the duplex unit (S6-3).
If there is a transfer sheet in the duplex unit, the operation from S14 onward is performed. If there is no transfer sheet in the duplex unit, the transfer sheet is fed from the sheet feeding cassette 41 to copy the image on the front side of the document (S6-4). Then, the transfer paper is conveyed to the duplex unit (S6-5), and the operation from S16 onward is performed. If it is determined in S6-2 that there is no image on the front side of the document, the image on the back side of the document is checked (S6-6), and it is determined whether or not there is an image on the back side of the document (S6-7). If there is no image, the operation from S16 onward is performed. If there is an image on the back side of the document, it is determined whether or not there is a transfer sheet in the duplex unit (S6-8). If there is a transfer sheet in the duplex unit, the transfer sheet is fed to perform the copy operation on the back side of the document (S6-9), and the processes from S15 are performed. If there is no transfer sheet in the duplex unit, the transfer sheet is fed from the sheet feeding cassette 41 to perform the copy operation on the back side of the document (S6-1).
0), send the transfer paper to the duplex unit (S6-1)
1), the processing from S16 onward is performed.

Here, the operation when a blank original is mixed in the double-sided original will be verified. If the blank sheet detection mode and double-sided-> double-sided mode are selected, the process proceeds from S6 to S7. Since there is no image on the back side of a blank document, the process proceeds from S8 to S11, but since there is no image on the front side, S12 to S12-1
Proceed to. At this stage, since the transfer paper has not been sent to the duplex unit, the process proceeds to S16, the original is discharged, and S17
Starts the operation for the next original. Therefore, even if a blank original is mixed in the double-sided original, the copy operation for the blank original is not performed.

If a single-sided original is mixed in the double-sided original, the process proceeds from S6 to S7 if the blank sheet detection mode and the double-sided → double-sided mode are selected. When a single-sided original is set face up, there is no image on the back side, so S8 to S1
Go to 1. Next, the image on the front side is detected, but since the transfer paper has not been sent to the duplex unit at this stage, S13
In step -1, the transfer paper is fed from the paper feed cassette and the image on the front side is copied. Then, the transfer paper is ejected (S15), and the single-sided original is ejected (S16). if,
When the one-sided original is set upside down, the image on the back side (original front side) is detected and the copy operation is performed (S9), and the transfer paper is stocked in the duplex unit (S9).
10) Do. Since there is no image on the front side (original back side), the process proceeds to S12-1. At this time, the transfer paper is stocked in the double-sided unit, but the copy operation is not performed on the transfer paper and the paper is not passed through the fixing unit (S12).
-2) The paper is discharged (S15). Then, the one-sided original is also ejected (S16). Therefore, when the one-sided original is mixed in the two-sided original, the blank page is not copied regardless of whether the one-sided original is facing upward or downward.

Further, when a blank original is mixed in the originals in the mode of copying a plurality of single-sided originals on both sides of the transfer paper, it is not the double-sided → double-sided mode, so the process proceeds to S6-1. Since there is no image on the front side of the blank document, the process proceeds to S6-6. However, since there is no image on the back side, the process proceeds to S16, the original is ejected, and the operation for the next original is started.
Therefore, the copy operation is not performed on the blank document.

In the mode for copying a plurality of single-sided originals on both sides of the transfer sheet, if the originals with wrong front and back are mixed, the mode is not the double-sided → double-sided mode, so the process proceeds to S6-1. Since there is no image on the front side of the document (original back side), S6
Then, the process proceeds to -6, then the image on the back side (original surface) is detected, and the process proceeds to S6-8. At this stage, since the transfer paper has not been sent to the duplex unit, the process proceeds to step S6-10, the paper is fed from the paper feed cassette, the back side (original front side) of the original is copied, and the transfer paper is sent to the duplex unit. To be And
A document with the wrong front and back is ejected (S16), and if there is a next document, the process proceeds from S17 to S4. Regarding the copy operation for the next original, since it is determined in S6-3 and S6-8 whether there is a transfer sheet in the duplex unit, the image of the next original is printed on the back side of the transfer sheet sent to the duplex unit first. Is copied. Therefore, copying is performed on both sides of the transfer paper.

As described above, even when a single-sided original or a double-sided original is copied on both sides of the transfer sheet, the copy operation is not performed on the blank side, and the original is automatically turned over to check the presence or absence of an image and the copy operation is performed. . Therefore, a blank copy is made on the opposite side of the transfer sheet which has been copied on one side, and there is no background stain due to toner adhesion. Further, when a single-sided original is mixed in the double-sided original, the transfer paper stocked in the double-sided tray is discharged without passing through the fixing unit, so that the temperature of the fixing heater is not lowered.

When the blank sheet detection mode is selected in the pressure plate mode not using the ADF 200, when a blank sheet original is detected, the copy operation is not performed and the original is displayed on the display (not shown) provided in the operation unit of the copying machine. An error message stating that is blank is displayed to alert the user.

[0050]

As described above, according to the image forming apparatus of the present invention, when the image data detecting means detects that there is an image on the original, the sheet feeding is started and the image can be formed. In addition, wasteful image formation is not performed on a blank surface of a document, and paper, power, time, etc. are not wasted.

According to the second aspect of the invention, the image data is input to the storage means (page memory) at the same time when the original is read, and at the same time, the image data detection means (detection circuit) detects whether or not there is an image in the data. Therefore, it is not necessary to perform prescan, and more reliable blank sheet detection can be performed.

According to the third aspect of the invention, when there is no image in the original fed by the ADF, the original is automatically turned over and the back side of the original is read, so that it is not necessary to set the original again and perform image formation again. .

According to the structure of claim 4, when there is no image on both sides (front and back) of the original fed by the ADF, the original is ejected from the ADF, so that no wasteful image formation is performed on a blank original. . Further, since the original is ejected without performing the image forming operation, the user can notice that there is a blank original.

According to the fifth aspect of the invention, the transfer paper stocked in the duplex unit can be discharged without passing through the image forming section depending on the selected copy mode and the presence or absence of an image on the original, so that one side is printed. It is possible to prevent the background stain of the transfer paper without performing a blank copy on the back side of the transfer paper on which the image is formed.

According to the structure of claim 6, when the transfer paper stocked in the duplex unit is discharged without passing through the image forming section, it can be discharged without passing through the fixing section. Since the temperature of the fixing unit does not drop due to the passing of the non-transfer sheet through the fixing unit, no unnecessary power is consumed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a copying machine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram showing an automatic document feeder installed in the copying machine.

FIG. 3 is a block diagram showing a control system of the copying machine.

FIG. 4 is a flow chart showing control in the copying machine when a single-sided original or a double-sided original is copied onto one side of a transfer sheet.

FIG. 5 is a first half of a flow chart showing a control when copying a double-sided original or a single-sided original on both sides of a transfer sheet in the copying machine, and the latter half is a splicer A;
Are connected with.

6 is a flowchart of the latter half part connected to the flowchart shown in FIG. 5, and the former half part is connected by a connector A;

[Explanation of symbols]

 1 Contact Glass 9 Line Image Sensor 12 Page Memory 13 Image Data Detection Circuit 31 Semiconductor Laser 35 Photoconductor 41 Paper Feeding Section 42 Fixing Unit 43 Transfer Paper Discharging Section 45 Duplex Unit 50 Copy Machine Main Body 70,71 Transfer Paper Conveying Path 100 Scanner Part 200 Automatic Document Feeder (ADF) 201 Document Table 217 Document Ejection Unit 210 Conveyor Belt 300 Printer Unit

Claims (6)

[Claims] 1. An automatic document feeder having an original reversing function, image reading means for reading an original image on a contact glass, and storage means for storing image data of the original read by the image reading means. An image forming unit that forms an image based on the image data stored in the storage unit and transfers the formed image onto a recording sheet; a sheet feeding unit that feeds the recording sheet to the image forming unit; and the recording sheet. A fixing unit for fixing the unfixed image transferred on the recording sheet, and a recording sheet reversing mechanism including a double-sided unit for stocking the recording sheet on one side of which is formed so as to enable image formation on both sides of the recording sheet. An image forming apparatus comprising: an image data detection unit for detecting the presence or absence of an image of a document read by the image reading unit, wherein the image data detection unit is a document image. A control unit is provided for starting the paper feeding by the paper feeding unit when it is detected that the image data is stored, and for reading the image data stored in the storage unit to control the image formation by the image forming unit. An image forming apparatus characterized by the above. 2. The original image on the contact glass is read by the image reading means, at the same time, the read image data is input to the storage means, and whether or not there is an image in the input image data is determined by the image. The image forming apparatus according to claim 1, wherein the image is detected by a data detecting unit. 3. When the image data detecting means detects that there is no image in a document fed by the automatic document feeder, the document is reversed by a document reversing function of the automatic document feeder and the image is read. The image forming apparatus according to claim 1, wherein the image is read again by means. 4. When the image data detection means detects that there is no image on both sides of a document fed by the automatic document feeder, the document is discharged from the automatic document feeder. The image forming apparatus according to claim 3. 5. A paper conveyance path for ejecting the recording paper in the duplex unit without passing through the image forming section is provided, and the image is output in accordance with the selected copy mode and the detection result of the image data detection means. The image forming apparatus according to claim 1, wherein a paper conveyance path that does not pass through the forming section or a paper conveyance path that leads to the image forming section is automatically selected. 6. The image forming apparatus according to claim 5, wherein the sheet conveying path that does not pass through the image forming unit can discharge the recording sheet in the duplex unit without passing through the fixing unit. apparatus.