JPH11129547A - Method for processing image information and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lacking of a character or a line due to an intermediate tone processing by a method wherein a thickness or density of a character or a line is changed based on the result of condition judgment of an attribute such as a density, a thickness, a color and a size of the character or line contained in image information outputted from an output device such as a printer. SOLUTION: Judgment by a predetermined condition is made relative to predetermined one or more attributes such as density or color, a kind of font, a size or thickness of a character or a line contained in image information 1 by a preprocessing section 2 provided in a front stage of a conversion section 3. Changing required for the predetermined one or more attributes is executed based on the judgment result. After the data is converted by an intermediate tone operation by using a dither method or an error diffusion method in terms of the preprocessed image information, it is transmitted to a printer 4 to be printed on a paper or the like. This system can be realized by a hardware or a program on a computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of processing image information output by an output device such as a printer, and more particularly to image information processing for improving the output quality of characters and lines included in image information. Related to the field.

[0002]

2. Description of the Related Art Continuous gradation (shading) of natural images and graphics contained in documents and the like created by a computer.
Is output using a printer having limited gradation expression capability, halftone processing is generally performed. As the halftone processing method, a dither method generally used for an electrophotographic printer and an error diffusion method generally used for an ink jet printer are known. Both methods change the ratio of dots printed on paper, etc.,
They are common in that they represent the gradation of an image.

Referring to FIG. 1, a general 2 × 1 dither method for an electrophotographic printer will be described. FIG. 1 (A)
As shown in (1), the gradations of two pixels a and b of the original image (monochrome) are expressed using two pixels A and B on paper. Density of pixels a and b of the original image (input) and density of pixels A and B (output)
Are represented by input / output relationships as shown by a solid line and a broken line in FIG. Thus, for example, FIG.
As shown in (B), when the density of the two pixels a and b of the original image is X, the density of the pixel A is 0 and the density of the pixel B is 2X.
If the size of the pixel is sufficiently small, two pixels A,
B alone cannot be recognized, and the two pixels A and B average the density X
Therefore, the relationship between the input density and the output density becomes substantially a linear input / output relationship as indicated by a dashed line in FIG. A typical value of X is 32,6
4,128.

[0004] The expression of gradation by the set of dark pixels and relatively lighter pixels is such that in an electrophotographic printer, a thin pixel having a density lower than a certain value is stably output alone. Is difficult, whereas dark pixels can be output stably. The image forming apparatus disclosed in Japanese Patent No. 2538121 is an example employing such a 2 × 1 dither method (however, in this example, the density level is expressed not by the dot density but by the dot size).

[0005]

The halftone processing is suitable for an image having a certain area, such as a natural image, but tends to cause inconvenience for characters and thin lines. For example, a pixel A as shown in FIG.
When there is a thin line having the density X only at the position corresponding to the above, as a result of the 2 × 1 dither processing, the density of the pixels constituting the thin line becomes 0 as shown in FIG. Will not be output at all. That is, there is a problem that a line segment or a part of a character having a density equal to or less than X is easily missing at the time of output. It is important to faithfully reproduce the density of the original image at the time of printing, but it is a minimum requirement that the characters can be output in a legible manner, and it is extremely undesirable that the characters are missing.

Although the description has been given of a monochrome image as an example, the same applies to a color image. Also,
Although the dither method has been described as an example, in the error diffusion method in which the density of an image is expressed by the number of dots, similarly, a line segment or a part of a character is likely to be missing in a low density portion (low dot density portion).

On the contrary, a problem may occur when printing a character or a line with high density in a specific color. For example, in an electrophotographic printer, cyan toner (colorant) is easily scattered due to material properties,
Cyan characters and thin lines have blurred outlines and tend to be thicker overall. Since the toner scattering is more likely to occur as the amount of toner increases, the effect is more likely to appear when printing high-density characters or lines. Further, the toner scattering causes a problem of thinning of a character or a thin line when the background is colored and a character or a thin line is white (a white character or a thin line).

Accordingly, an object of the present invention is to prevent the loss of characters and lines due to the above-described halftone processing when outputting image information with a printer or the like, and also to prevent a character or line of a specific color from being lost. An object of the present invention is to improve the output quality of characters and lines by canceling or suppressing the influence of toner diffusion.

[0009]

The gist of the present invention to achieve the above object is to provide a method for outputting image information to be output by an output device such as a printer with respect to the density and thickness of characters or lines included in the image information. , Color, size, font type, etc., to determine the condition of one or more predetermined attributes, and to change the thickness or density of characters or lines according to the result of the condition determination. Embodiments including those embodiments and combinations thereof are included.

(1) A method in which a condition determination regarding the density of characters or lines included in image information is performed, and the thickness or density of the characters or lines is changed according to the result of the condition determination. According to this method, for a low-density character or line that may be lost due to halftone processing, the thickness or the density of the character can be avoided by increasing the thickness or increasing the density. .

(2) A method of making a condition judgment on the density and font type of a character included in image information, and changing the thickness or density of the character according to the result of the condition judgment. According to this method, if a low-density character in which a drop is likely to occur is a thin font in which a drop is likely to occur, the loss can be prevented by increasing the thickness of the character or increasing the density. on the other hand,
If the character is a bold font that does not easily lose, the original thickness or density can be reproduced as faithfully as possible without changing the thickness or density.

(3) A method of making a condition judgment regarding the density and thickness of characters or lines included in image information, and changing the thickness or density of characters or lines according to the result of the condition judgment. According to this method, if a low-density character or a line in which a drop is likely to occur is a thin character or a line in which a drop easily occurs, the drop can be avoided by increasing the thickness or the density. . On the other hand, in the case of a thick character or line that is unlikely to be lost, the original thickness or density can be reproduced as faithfully as possible without changing the thickness or density.

(4) A method in which a condition determination regarding the density and size of a character included in image information is performed, and the thickness or density of the character is changed according to the result of the condition determination. According to this method, if the low-density character that is likely to be dropped is a small-sized character that is likely to be crushed, do not change the thickness or density to avoid crushing, or increase the density. Crushing and omission can be prevented.

On the other hand, if the character has a large size, the loss can be avoided by increasing the thickness or the density.

(5) A method of performing a condition judgment on the color of a character or line included in image information, and changing the thickness or density of the character or line according to the result of the condition judgment. According to this method, for characters or lines of a specific color, such as cyan, in which toner scattering of an electrophotographic printer is likely to occur, by reducing the thickness, the thickening of characters or lines due to toner scattering is offset, or By reducing the toner density by lowering the density, thickening of characters and lines can be suppressed. Further, with respect to the outline characters and lines, by increasing the thickness thereof, the thinning of the characters and lines due to the influence of toner scattering can be offset.

(6) A method in which a condition determination regarding the color and density of a character or a line included in image information is performed, and the density of the character or line is changed according to the result of the condition determination. According to this method, for a high-density character or line in a specific color in which toner scattering is likely to occur and the degree of toner scattering is large, the toner scattering is reduced by lowering the density to suppress thickening of the character or line. Can be.

(7) A method of making a condition judgment on the color and font type of a character included in image information and changing the thickness or density of the character according to the result of the condition judgment. According to this method, if the font type is a small-sized font in which toner scattering is likely to occur and the font type is conspicuous due to toner scattering, the thickness is reduced to offset the thickening, or the density is reduced to reduce the toner density. Scattering can be suppressed and fat can be reduced. If the characters are outlined characters, thinning due to toner scattering can be offset by increasing the thickness. On the other hand, with a bold font, the original thickness and density can be reproduced as faithfully as possible without changing the thickness or density.

(8) A method of making a condition judgment on the color and thickness of a character or a line included in image information and changing the thickness or density of the character or line according to the result of the condition judgment. According to this method, in a character or line of a specific color in which toner scattering is likely to occur, for thin characters or lines in which toner scattering is conspicuous,
The thickness can be reduced to offset the thickness, or the density can be reduced to reduce toner scattering and suppress the thickness. On the other hand, for thick characters and lines where toner scattering is inconspicuous,
The initial thickness and density can be reproduced as faithfully as possible without changing the thickness or density.

(9) A method in which a condition judgment regarding the color and size of a character included in image information is performed, and the thickness or density of the character is changed according to the result of the condition judgment. According to this method, for characters of a specific color in which toner scattering is likely to occur, and for small-sized characters in which fading is likely to occur, the density is reduced to reduce toner diffusion, thereby suppressing the fatness of the character, and increasing the size of large-sized characters. Can be reduced in thickness to offset thickening due to toner scattering.
In addition, if the white characters are large characters of a predetermined size or more, the thickness is increased to offset the thinning due to toner diffusion, and if the characters are small characters less than the predetermined size and are likely to be crushed, the thickness is increased. Without crushing.

According to a preferred embodiment of the present invention,
The above-described condition determination regarding the attribute of the character or line and the change of the thickness or density of the character or line according to the result are performed when the image information is output by an output device such as a printer on the computer. This is accomplished by a device driver associated with the output device operating at.

[0021]

FIG. 3 shows the basic configuration of a system for carrying out the present invention. Conventionally, the image information 1 to be printed out is converted into data in a format suitable for the printer 4 by the conversion unit 3 and then sent to the printer 4 to be printed out on paper or the like. The halftone processing by the dither method or the error diffusion method is executed by the conversion unit 3. When the printer 4 has a built-in controller, some functions of the conversion unit 3 are performed by the built-in controller.

According to the present invention, the preprocessing unit 2 is added before the conversion unit 3. In the pre-processing unit 2, one or more predetermined attributes such as the density and color, the character font type, the character size, and the character and line thickness of the characters and lines included in the image information 1 are set. In this case, a predetermined condition is determined, and necessary changes are made to one or more predetermined attributes based on the result of the determination. The conversion unit 3 performs the same data conversion as before on the preprocessed image information.

Such a system can be realized by hardware or by a program on a computer. When the functions are implemented by a program, the functions of the pre-processing unit 2 can be implemented by being incorporated in an application program, but it is most practical to implement the functions by incorporating them into a device driver (printer driver). This is because the specific contents of the condition determination and change of the attribute in the pre-processing unit 2 are closely related to the printing method of a specific printer, but the program directly related to the specific printer is a printer driver. Because there is. When printing characters from an application program, the operating system issues a character output command in which attribute information such as font type, size, thickness, density, and color is set to the printer driver. This is because, in general, it is easy for the printer driver to handle the condition determination and the change regarding the attribute of the character. Similarly, when printing a line from an application, a line output command in which attribute information such as the type, thickness, density, and color of the line is set is generally issued from the operating system to the printer driver. This is because it is easy for the printer driver to handle the condition determination and change regarding the line attribute.
Further, it is possible to easily cope with a change of a printer or various printers.

An embodiment in which the function of the preprocessing unit 2 is incorporated in a printer driver will be described below.

FIG. 4 schematically shows an example of a hardware configuration of a computer for such an embodiment. 4 includes a CPU 10, a memory 11, a hard disk 12, a display 13, a scanner 14, an input device 15 such as a keyboard and a mouse, a printer 16, and a disk for reading and writing on a disk recording medium 17 such as a floppy disk or a CD-ROM. This is a general hardware configuration in which a drive 18, a modem 19, and the like are connected by a bus 20. In FIG. 4, the interface means with each device of the bus 20 is omitted for simplification.

The document to be printed out is not limited to being created from the beginning by the application program, but may be input from outside. For example, the data is read by the scanner 14, read from the disk recording medium 17 via the disk drive 18, or input from a communication line via the modem 19. Image information input from outside is directly stored in memory 11
Or temporarily stored in the hard disk 12, and then read into the memory 11 during processing.

An application program relating to printout of a document or the like, an operating system,
Generally, a program such as a printer driver corresponding to the printer 16 is read from a disk recording medium 17 such as a CD-ROM or a floppy disk via a disk drive 18 and stored in the hard disk 12, or is connected to a modem via a communication line. 19 and stored in the hard disk 12. These programs are partially or wholly loaded into the memory 11 and executed by the CPU 10 as necessary.

FIGS. 5 and 6 show the relationship between the flow of a printout process and the program when the present invention is implemented by a program on such a computer. FIG. 5 shows a flow of a typical printout process when the printer 16 has a controller, and FIG.
6 shows the flow of a typical printout process in the case where the printer 6 does not have a built-in controller.

First, a description will be given with reference to FIG. Reference numeral 20 denotes an application program for printing out a document or the like, 21 denotes an operating system, 22 denotes a printer driver, and 23 denotes a PDL (Prin
A controller of the printer 16 equipped with an engine of ter Description Language (24) is a printing mechanism of the printer 16. The printer driver 22 has a configuration in which a pre-processing portion 26 (corresponding to the pre-processing portion 2 in FIG. 3) is added to a main body portion 25 for performing command conversion and data conversion as in the related art. The specific processing contents of the preprocessing section 26 will be described later.

When printing out a document or the like, the application program 20 instructs the operating system 21 to execute an API (Application Programming Intemet).
rface) issues print commands (printing of characters, printing of graphics (graphs, etc.), printing of images (natural images, etc.), etc.) called functions. Then, the operating system 21 issues a print command (characters, graphics, images, etc.) to the printer driver 22. This instruction is called a DDI (Device DriverInterface) function. In the pre-processing portion 26, the printer driver 22 makes a condition determination regarding the attribute information of the characters and lines described in the print command, makes necessary changes to the specific attribute information according to the result, and then outputs the attribute information. Transfer to main body part 22. The specific contents of the processing in the preprocessing section 26 will be described later. Main part 22 of printer driver 22
Performs a command conversion and a data conversion similar to those of the related art to a print command from the operating system 21, and sends a PDL (Printer Description Language) to the controller 23 of the printer 16 via the operating system 21.
ge; print instructions (characters, graphics, images, etc.) described by PostScript, PCL, ESCPage, etc.)
Issue The controller 23 of the printer 16 converts the PDL print command into drawing data for the printing mechanism 24 (including rasterization, that is, bitmap expansion, as well as halftone processing using a dither method or an error diffusion method). Print out to 24.

If the printer 16 is an inexpensive printer without a controller, for example, an ink jet printer, the flow of the printout process is slightly different. This will be described with reference to FIG. 30 is an application program for printing out documents and the like, 31
Denotes an operating system, and 32 denotes a printer driver. The printer driver 32 includes a preprocessing part 3 in a main body part 33 for mainly performing data conversion similar to the conventional one.
4 (corresponding to the pre-processing unit 2 in FIG. 3).
The specific processing content of the preprocessing section 34 will be described later.

When printing out a document or the like, the application program 30 issues a print command (API) to the operating system 31, and the operating system 31 issues a print command (DDI) to the printer driver 32. In the pre-processing portion 34, the printer driver 32 makes a specific condition determination regarding the attribute information of the characters and lines described in the print command, and makes necessary changes to the specific attribute information according to the result. Is passed to the body part 33. This preprocessing part 3
4 will be described later. Printer driver 3
The main part 33 of the second performs mainly data conversion similar to the conventional one in response to a print command from the operating system 31 (converts data on an application program passed as an argument of the print command into data for a printer). , And converts the converted print instruction into the operating system 3.
Return to 1. The operating system 31 executes a print command having the received printer data, performs rasterization and halftone processing to generate drawing data for the printer, and causes the printer 16 to print out the drawing data.

A first example of the processing by the pre-processing portions 26 and 34 of the printer drivers 22 and 32 will be described with reference to the flowchart shown in FIG. It is assumed that the 2 × 1 dither processing described with reference to FIG. 1 is performed as the halftone processing. Also, consider the case of outputting a monochrome image.

In the preprocessing section, when a print command is issued from the operating system, it is determined whether the output target is a character or a line (steps S1 and S2). If it is a character, the determination in steps S3 to S6 is performed for the attribute information. First, it is determined whether the designated density (input density) is equal to or lower than X (step S3). This X corresponds to X shown in FIG. If the density is less than or equal to X, the font type is Mincho (Mincho font) represented by Mincho
Is determined (step S4). If it is a Mincho font, it is determined whether bold character processing has been designated by the application program (step S5). It can be seen from the thickness specified in the thickness attribute information whether the bold character processing is specified. If bold character processing is not specified, the font size is set to the preset number of points f.
It is determined whether it is (for example, 4) or more (step S6).
If all of the conditions of steps S3 to S6 are satisfied, the attribute information of the character thickness is changed to a larger specified value such that partial deletion of low-density characters due to the halftone processing is less likely to occur. That is, a thick conversion is performed (step S7).

It should be noted that characters having a density exceeding X, characters of bold fonts other than Mincho fonts (thin fonts), and characters designated for bold character processing are excluded from the objects of the bold conversion (steps S3 and S4). , S5), because they are originally unlikely to be missing, so that the original thickness can be reproduced as faithfully as possible. The reason why small-sized characters are excluded (step S6) is that when the thickness is increased, the characters are likely to be crushed.

When the output target is a line, the density is X
It is determined whether or not the line width is equal to or smaller than (step S8), and if so, it is determined whether or not the line thickness is equal to or smaller than a preset W (for example, W = 1 pixel) (step S9). If both conditions are satisfied, the attribute information of the line thickness is changed to a specified value such that line missing hardly occurs due to the halftone processing, that is, a thick conversion is performed (step S10). Dark lines and thick lines that are unlikely to be missing are excluded from the target of the thick conversion (steps S8 and S9), and the original thickness of the lines is reproduced as faithfully as possible. Since thick conversion of thick lines is not performed, it is possible to cope with thick line processing designation by an application program. Also, if the output target is neither a character nor a line, it is also excluded from the thick conversion.

FIG. 8 shows the effect of such a thick conversion (steps S7 and S10) by the pre-processing portion of the printer driver.
This will be described below. It is assumed that the original image has a thin line of one pixel in thickness or a thin line portion of a font as shown in FIG. Assuming that the 2 × 1 dither processing described with reference to FIG. 1 is performed as the halftone processing, the thin line or the thin line portion disappears unless the thickness conversion is performed. According to the present invention, in the preprocessing portion of the printer driver, the thickness of the thin line or the thin line portion is converted to a specified value (for example, 1 <specified value ≦ 3). For example, if the specified value is 3,
This thin line or thin line portion is thickened as shown in FIG.
Assuming that the density of the pixel in the thick portion is Y (for example, Y = X), the thin line or the thin line portion becomes two lines of density 2Y as shown in FIG. Is done. When this is printed out, the pixels are sufficiently small, and scattering of toner, thickening of lines, bleeding of ink, and the like occur, so that these two lines are substantially perceived as one line.

When the error diffusion processing is employed as the halftone processing, a thin line having a thickness of one pixel as shown in FIG. 8A is output as a dot row as shown in FIG. 9A by the halftone processing. You. On the other hand, when the halftone processing is performed on the result of the bold conversion as shown in FIG. 8B, a dot row is output as shown in FIG. 9B, and a thin line is missing when compared with FIG. 9A. It is clear that they are hard to perceive.

A second example of the processing by the pre-processing portions 26 and 34 of the printer drivers 22 and 32 will be described with reference to the flowchart shown in FIG. It is assumed that the 2 × 1 dither processing described with reference to FIG. 1 is performed as the halftone processing. Also consider the case of outputting a monochrome image.

The preprocessing portion of the printer driver first determines whether the output target is a character or a line (step S).
21, S22). If it is a character, the determination in steps S23 to S26 is performed for the attribute information. First, it is determined whether the designated density (input density) is not 0 and is a certain value larger than X, for example, 4X / 3 or less (step S23). Note that X corresponds to X shown in FIG. If the density is not 0 and is 4X / 3 or less, it is determined whether the font type is a thin font (Mincho font) represented by Mincho (Step S24). If it is a Mincho font, it is determined whether bold character processing has been designated by the application program (step S25). If the bold character processing is not specified, it is determined whether the font size is equal to or larger than a preset point number f (for example, 4) (step S26).

If the conditions of steps S23 to S26 are all satisfied, the attribute information of the character thickness is changed to a larger specified value, that is, converted to a thicker value (step S2).
7). On the other hand, for a character for which any of the conditions of steps S23 to S26 is not satisfied, the attribute information of the density of the character is changed to a specified value larger than X, in this example, 4X / 3 (step S28).

As described above, in the second example, the density is 4
Even if the characters are smaller than X / 3, if the characters are bold fonts or bold character processing is specified, bold conversion is not performed to reproduce the thickness as faithfully as possible, and small fonts are prevented from being crushed. Therefore, do not perform thick conversion. Instead,
By increasing the density of the characters to 4X / 3, the characters are prevented from being lost due to halftone processing.

If the output target is a line, it is determined whether the density is not 0 and not more than 4 × / 3 (step S2).
9) If so, it is determined whether the line thickness is equal to or smaller than a preset W (for example, W = 1 pixel), that is, whether there is a thick line processing instruction (step S30). If both conditions are satisfied, the attribute information of the density of the line is changed to a specified value such that line missing is unlikely to occur due to the halftone processing, in this example, 4X / 3. If the line does not satisfy any of the conditions of steps S29 and S30, or if the output target is neither a character nor a line, neither the density nor the thickness is changed.

As is clear from the above description, this second
The conversion of the density in the example shown in FIG.
This is equivalent to changing the density relationship between the original image pixels a and b and the output pixels A and B in the x1 dither process to the relationship shown by the solid line and the broken line in FIG. 11, respectively. The input / output relationship of the substantial density in units of two pixels is shown in FIG.
It becomes like the one-dot chain line of 1. Therefore, although the gradation of the low density portion cannot be expressed, if the density is other than 0, no dropout occurs in principle even at a low density.

When it is desired to express the gradation of the low density portion, for example, when the density of a character or a line is d in steps S28 and S31, the density is changed to [d / 4 + X]. Is also good. This is equivalent to changing the input / output relationship of the density by the dither processing as shown in FIG. 12, and it is possible to express a certain amount of gradation even in a low density portion.

Although the case where the halftone processing by the dither method is performed has been described above, it is apparent that the same effect can be obtained also when the halftone processing by the error diffusion method is performed.

Although a monochrome output has been premised heretofore, a similar preprocessing can be performed when performing color output. However, in the case of color output, the printer driver receives the character or line color as attribute information from the operating system as RGB values or CMYK values. For example, the contents of steps S23 and S29 and steps S28 and S31 in FIG. Each of them needs to be changed as shown in FIGS. The procedure shown in FIG. 13 assumes a case where color attribute information is given as RGB values from 0 to 255.

Steps S41 and S42 in FIG. 13A are procedures corresponding to step S23 or step S24 in FIG. First, in step S41, R provided as color attribute information from the operating system
The GB values are regarded as the RGB values of the standard color space sRGB proposed by Hewlett-Packard and Microsoft, and are converted into the CIE XYZ color space by the following (Equation 1), which is further converted into the CIE Lab color space. Conversion between the XYZ color space and the Lab color space is well known. For example, the book “Noboru Ota,“ Color Engineering ”, Tokyo Denki University Press, pp.128-1
31 ".

[0049]

(Equation 1)

In the next step S42, it is determined whether or not the lightness L of the CIE Lab color space calculated in the previous step is equal to or less than a specified value L '(corresponding to the density value 4X / 3 in steps S23 and S29). Note that the density (gradation) is specifically the amount of the colorant, but here, the lightness L in the CIE Lab color space is regarded as the density in order to simplify the processing.

Steps S51 and SS5 in FIG.
Steps S2 and S53 correspond to step S28 or step S31 in FIG. First, in step S51, after changing the lightness L of the Lab value obtained in step S41 to the specified value L ', the Lab value is converted to an XYZ value. In the next step S52, the obtained XYZ values are converted into sRGB values according to (Equation 1). Next step S5
In step 3, the RGB values of the attribute information are obtained from the sR obtained in the previous step.
Rewrite with GB value.

A third example of the processing by the pre-processing portions 26 and 34 of the printer drivers 22 and 32 will be described with reference to the flowchart shown in FIG. This example is for color output.

First, it is determined in step S61 whether or not the output target is a character. If not, it is determined in step S62 whether or not the output target is a line.

If it is a character, it is determined whether or not the color specified by the attribute information is cyan in which toner diffusion is likely to occur (step S63). If it is cyan, it is specified that toner scattering must be considered. It is determined whether the density is equal to or higher than the value (step S64).

When the color attribute information is given by RGB values, as described with reference to FIG.
The lightness L in the Lab color space can be regarded as the density. Even for cyan, if the density is less than the specified value, it is determined that the influence of toner diffusion is small, so that the color attribute information relating to this character is not changed.

If the character is a cyan character having a density equal to or higher than the specified value, it is next determined whether the character is a Mincho font (fine font) (step S65). If the font is not a thin Mincho font, it is determined that the fatness due to toner diffusion is inconspicuous, so that the thickness attribute information is not changed. If it is a Mincho font, it is determined whether or not bold character processing is specified (step S66). If specified, it should be output as a bold character, so it is determined that there is no need to correct the boldness due to toner diffusion, so the thickness attribute information is not changed.

If there is no bold character processing designation, thickening of toner diffusion may cause a problem. However, if correction is performed to reduce the thickness of small-sized characters so as to offset the thickening due to toner diffusion, blurring will occur. There is a risk of occurring. Therefore, it is determined whether the font size is equal to or more than a predetermined number of points f (for example, f = 4) (step S67). When the font size is equal to or more than the predetermined number of points f, the attribute information of the character thickness is further changed. The value is changed to a thin specified value, that is, a thin conversion of characters is performed (step S68). If the font size is less than the predetermined number of points f, the density is changed to a specified value that reduces the toner diffusion amount, that is, the color attribute information is changed so as to be lighter (step S69).
The change of the density can be performed by the procedure described with reference to FIG.

If it is determined in step S63 that the character color is not cyan, it is determined whether the color is white (step S63).
70). White characters and lines with a colored background, that is, white characters and lines, tend to be thin due to the effect of toner diffusion. Therefore, if it is a white character, it is determined whether it is a Mincho font (fine font) (step S71). If the font is not a Mincho font, it is determined that thinning is unlikely to be a problem, and the attribute information is not changed.

In the case of a Mincho font in which the effects of thinning are conspicuous, there is no bold character processing designation (step S72), and if the font size is equal to or larger than a predetermined number of points f (step S73), the character thickness is changed. The attribute information is changed to a thicker specified value (step S74). However, even for Mincho fonts, the attribute information is not changed for characters for which bold character processing is specified because the effect of thinning due to toner diffusion is inconspicuous. In addition, small characters having a font size less than the predetermined number of points f may be crushed if corrected to increase the thickness of the characters.
The attribute information that makes the characters thicker is not changed.

If the output target is a line, it is first determined whether the color is cyan (step S75). If it is cyan, it is determined whether or not the density is equal to or higher than a specified value (step S76). Here, as described with reference to FIG. 13A, the brightness may be regarded as the density. If the density is lower than the specified value in which the toner diffusion should be considered, the attribute information is not changed. If the density is equal to or greater than the specified value, it is determined whether the line thickness is equal to or greater than the specified value W (step S77). If the density is less than the specified value, blurring occurs when correction is performed to reduce the line thickness. Since there is concern, the attribute information of the color is changed to a specified value so as to increase the density of the line (step S79). However, if the line has a thickness equal to or larger than the specified value, the line thickness attribute information is changed to a smaller specified value in order to cancel the line thickness due to toner diffusion (step S78).

If the color of the line is not cyan, it is determined whether the color is white (step S80). If it is not white, the attribute information is not changed. In the case of a white line, it is determined whether or not the thickness is equal to or smaller than a specified value W (step S81). If the thickness is equal to or smaller than the specified value, the thickness of the line is canceled so as to cancel the thinning due to the influence of toner diffusion. The thickness attribute information is changed to a larger specified value (step S82). Lines thicker than the specified value do not change the attribute information because thinning due to toner diffusion is not a problem.

If a user interface is provided in the printer driver, it is possible to set the prescribed values of the density and thickness related to the processing described above and to specify the target attribute for the condition judgment without changing the application program. Can be arbitrarily performed on the user side. This is also an advantage of the method in which the pre-processing is executed by the printer driver.

[0063]

As is apparent from the above description, according to the first aspect of the present invention, the density and thickness of characters and lines included in image information output by an output device such as a printer are determined.
By changing the thickness or density of characters or lines according to the result of condition determination of attributes such as color, size, font type, etc.
Prevents loss of characters and lines due to halftone processing, offsets or reduces thickening and thinning of characters and lines due to toner diffusion, and prevents crushing and fading of thin fonts and small size characters. The output quality of characters and lines can be improved. According to the second aspect of the present invention, the output quality of characters and lines can be easily improved only by a partial change of a device driver without changing an application program or an operating system.
Further, it is possible to easily cope with a change in the output device or various types of output devices. According to the third aspect of the present invention, a general computer can be used to implement the first or second aspect of the invention to improve the output quality of characters and lines.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of 2 × 1 dither processing.

FIG. 2 is an explanatory diagram of missing thin lines due to dither processing.

FIG. 3 is a block diagram showing a basic configuration of a system for implementing the present invention.

FIG. 4 is a block diagram illustrating an example of a computer for implementing the present invention.

FIG. 5 is a diagram illustrating a flow of a typical printout process and a related program when a printer having a controller is used.

FIG. 6 is a diagram showing a flow of a typical printout process and a related program when a printer having no controller is used.

FIG. 7 is a flowchart illustrating an example of processing in a preprocessing portion of the printer driver.

FIG. 8 is an explanatory diagram of an effect of increasing the thickness of a character or a line when dither processing is used as halftone processing.

FIG. 9 is an explanatory diagram of the effect of increasing the thickness of a character or a line when error diffusion processing is used as halftone processing.

FIG. 10 is a flowchart illustrating another example of the processing in the preprocessing portion of the printer driver.

FIG. 11 is a diagram showing the input / output relationship of the density of two pixels related to FIG.

FIG. 12 is a diagram showing a modification of the input / output relationship of the density of two pixels.

FIG. 13 is a flowchart illustrating a procedure of density determination and density change when a color image is handled.

FIG. 14 is a flowchart illustrating another example of the processing in the preprocessing portion of the printer driver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input image information 2 Pre-processing part 3 Conversion part 4 Output device 10 CPU 11 Memory 12 Hard disk 16 Printer 17 Disk information recording medium 18 Disk drive 20 Application program 21 Operating system 22 Printer driver 23 Printer controller 26 Printer driver pre-processing part 30 application program 31 operating system 32 printer driver 34 pre-processing part of printer driver

Claims (3)

[Claims] An image information to be output by an output device such as a printer is provided with a predetermined value such as density, thickness, color, size, font type, etc. of characters or lines included in the image information.
An image information processing method, comprising: performing a condition determination on at least one attribute, and changing the thickness or density of a character or a line according to a result of the condition determination. 2. When outputting image information by an output device such as a printer in a computer, a device driver associated with the output device operating on the computer operates to output the density and thickness of characters or lines included in the image information. Well,
An image information processing method comprising: performing a condition determination regarding one or more predetermined attributes such as a color, a size, and a font type, and changing the thickness or density of a character or a line according to a result of the condition determination. . 3. A procedure for determining conditions relating to one or more predetermined attributes such as density, thickness, color, size, font type, etc. of characters or lines included in image information to be output by an output device such as a printer. And a program for causing a computer to execute a procedure for changing the thickness or density of characters or lines in accordance with the result of the condition determination.