JP2006287461A - Image processing apparatus, image forming apparatus, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an image quality caused by a generation copying from being degraded without increasing a working load imposed on a user. <P>SOLUTION: A CPU 710 of a control section 700 of a copying machine 1 includes: an output image generating section 714 for reading original image data to produce output image data being print output image data; a dot ratio calculation section 715 for obtaining a ratio of number of dots by each prescribed development color of the output image data to the total number of dots included in the output image data as an output dot ratio; and an image correction section 716 for correcting the output image data on the basis of the output dot ratio and an original dot ratio, and a RAM 720 includes: an original image storage section 721 for storing the original image data; and a dot ratio storage section 722 for storing the original dot ratio. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a print output image from original image data which is image data generated by optically reading and photoelectrically converting a color original printed in advance with a predetermined developing color on recording paper by one image forming apparatus. The present invention relates to an image processing apparatus, an image forming apparatus, and an image processing program that generate output image data as data.

  When the recording paper on which the document image is printed is read as a document and the output obtained by copying is repeated again as a document (so-called generation copy), reading associated with the copy is performed. The quality of the output image may deteriorate due to the influence of noise mixing, various image processing applied to reading, and the like. For example, when the characters are unclear or the color of the color image is changed, the image quality is deteriorated.

Various proposals have been disclosed for the problem of image quality degradation caused by such a generation copy. For example, Patent Document 1 discloses parameters used when copying from a normal document that is not copy output (hereinafter referred to as a source document) and parameters used when the document is a copy output (hereinafter referred to as a copy document). There has been proposed an image processing apparatus that is provided and switches these operations by a user.
JP-A-3-284057

  However, in the above configuration, it is necessary for the user to visually determine whether the document is a source document or a copy document, and to perform an operation of switching parameters, which is complicated for the user. was there. In particular, when the original document and the copy document are mixed, the load required for this work increases, and the above problem is likely to become apparent.

  The present invention has been made in view of the above problems, and provides an image processing apparatus, an image forming apparatus, and an image processing program capable of suppressing deterioration in image quality associated with generation copying without increasing a user's work load. It is for the purpose.

  The image processing apparatus according to claim 1 is an original image which is image data generated by optically reading a photoelectrically converted color original printed on a recording sheet with a predetermined developing color by one image forming apparatus in advance. An image processing apparatus that generates output image data that is image data for print output from data, wherein the original image storage means for storing the original image data and the color original are printed by the first image forming apparatus A ratio of the number of dots for each predetermined development color with respect to the total number of dots in the printed range at the time, and a document ratio storing unit that reads the document image data from the document image storage unit. Output image generation means for generating the output image data composed of the predetermined development color, and the number of dots included in the output image data A dot ratio calculating means for obtaining a ratio of the number of dots for each predetermined development color of the output image data as an output dot ratio; and an image correcting means for correcting the output image data based on the output dot ratio and the document dot ratio. It is characterized by providing.

  9. The image processing program according to claim 8, comprising a computer, and image data generated by optically reading a color original printed in advance with a predetermined developing color on a recording sheet by one image forming apparatus and performing photoelectric conversion. An image processing apparatus image processing program for generating output image data that is image data for print output from original image data, wherein the computer includes original image storage means for storing the original image data, and the color original A dot ratio storage means for storing, as a document dot ratio, a ratio of the number of dots for each predetermined development color to the total number of dots within the printed range when the image is printed in the image forming apparatus according to claim 1; An output for reading the original image data from the image storage means and generating the output image data composed of the predetermined development color An image generating means; a dot ratio calculating means for obtaining a ratio of the number of dots for each predetermined development color of the output image data to the total number of dots included in the output image data as an output dot ratio; the output dot ratio and the document It is characterized by functioning as image correction means for correcting the output image data based on the dot ratio.

  According to these inventions, the image data is generated by optically reading and photoelectrically converting a color original printed in advance with a predetermined developing color on a recording paper by one image forming apparatus in the original image storage means. The ratio of the number of dots for each predetermined development color with respect to the total number of dots within the printed range when the original image data is stored and the color original is printed by the image forming apparatus of one in the dot ratio storage means Is stored as the document dot ratio.

  Then, the original image data is read from the original image storage means by the output image generation means, and output image data composed of a predetermined development color is generated, and all of the image data included in the output image data is generated by the dot ratio calculation means. The ratio of the number of dots for each predetermined development color of the output image data to the number of dots is obtained as the output dot ratio. Further, the output image data is corrected based on the output dot ratio and the document dot ratio by the image correcting means.

  Therefore, the output dot ratio, which is the ratio of the number of dots for each predetermined development color of the output image data to the total number of dots included in the output image data, and the number of dots for each predetermined development color with respect to the total number of dots within the printed range Since the output image data is corrected based on the original dot ratio, which is the ratio of the above, it is possible to suppress the deterioration of the image quality associated with the generation copy without increasing the user's work load.

  That is, since the ratio of the number of dots for each predetermined development color of the image data to the total number of dots represents the hue of the entire image, the entire output image and document image are respectively determined by the output dot ratio and document dot ratio. The shade of is expressed.

  The image processing apparatus according to claim 2, wherein the image correction unit corrects the output image data so that the output dot ratio substantially matches the original dot ratio for each of the predetermined development colors. Yes.

  According to the above-described configuration, the output image data is corrected by the image correction unit so that the output dot ratio substantially matches the original dot ratio for each predetermined development color.

  Therefore, since the output image data is corrected so that the output dot ratio substantially matches the original dot ratio for each predetermined development color, the color tone of the entire output image is matched with the overall color tone of the original image, resulting in generation copy. The deterioration of image quality is further suppressed.

  The image processing apparatus according to claim 3, a dot ratio image generation unit that reads out the original dot ratio stored in the dot ratio storage unit and generates dot ratio image data that is image data representing the original dot ratio; The output image data corrected by the image correction unit is combined with the dot ratio image data to further correct the output image data.

  According to the above configuration, the dot ratio image generation unit reads the document dot ratio stored in the dot ratio storage unit, and generates dot ratio image data that is image data representing the document dot ratio. Then, the image composition means synthesizes the dot ratio image data with the output image data corrected by the image correction means to further correct the output image data.

  Accordingly, the dot ratio image data, which is image data representing the document dot ratio, is synthesized with the output image data, and the output image data is corrected. Therefore, the document dot ratio can be read from the output image data.

  The image processing apparatus according to a fourth aspect is characterized in that the dot ratio image generation means generates dot ratio image data in a form that is difficult to visually recognize when printed out.

  According to the above configuration, the dot ratio image generation unit generates dot ratio image data in a form that is difficult to visually recognize when printed out.

  Accordingly, since the dot ratio image data is generated in a form that is difficult to visually recognize when printed out, the image quality of the output image is reduced due to the dot ratio image data being combined with the output image data. It is suppressed.

  The image processing apparatus according to claim 5, wherein the dot ratio image generation unit generates the dot ratio image data in a predetermined color that is difficult to visually recognize.

  According to the above configuration, the dot ratio image generation unit generates the dot ratio image data in a predetermined color that is difficult to visually recognize.

  Therefore, since the dot ratio image data is generated in a predetermined color that is difficult to visually recognize, the dot ratio image data that is difficult to visually recognize is easily generated. For example, the dot ratio image may be generated in a predetermined position as a numerical value by associating the dot ratio with a character such as a symbol representing each development color.

  The image processing apparatus according to claim 6, wherein it is determined that the document image determination unit that determines whether or not the dot ratio image data is included in the document image data, and the dot ratio image data. A document dot reading means for obtaining the document dot ratio and storing it in the dot ratio storage means.

  According to the above configuration, when the document image determination unit determines whether or not the dot ratio image data is included in the document image data, and determines that the dot ratio image data is included, the document dot reading is performed. The document dot ratio is obtained by the means and stored in the dot ratio storage means.

  Accordingly, when it is determined that the original image data includes dot ratio image data, the original dot ratio is obtained, so that it is not necessary for the user to determine whether the original is a copy original. Thus, it is possible to reduce the user's work load and generate an output image in which deterioration of image quality is suppressed by using the read document dot ratio.

  According to a seventh aspect of the present invention, there is provided an image forming apparatus according to any one of the first to sixth aspects, and an original reading unit that optically reads an original image and performs photoelectric conversion to generate the original image data. And printing means for forming the output image data as an image on a recording paper.

  According to the above configuration, an original image is optically read by the original reading unit, photoelectrically converted to generate original image data, and image quality deterioration is caused by the image processing apparatus according to claim 1. Is generated. Then, output image data is formed as an image on the recording paper by the printing means.

  Therefore, an image forming apparatus capable of suppressing a decrease in image quality associated with generation copying without increasing the user's workload is realized.

  According to the first and eighth aspects of the invention, the output dot ratio, which is the ratio of the number of dots for each predetermined development color of the output image data to the total number of dots included in the output image data, Since output image data is corrected based on the original dot ratio, which is the ratio of the number of dots for each predetermined development color to the number of dots, it suppresses degradation in image quality associated with generation copying without increasing the user's workload. Can do.

  According to the second aspect of the present invention, the output image data is corrected so that the output dot ratio substantially matches the original dot ratio for each predetermined development color. It is possible to further suppress the deterioration in image quality associated with the generation copy by matching with the hue.

  According to the third aspect of the invention, since the output image data is corrected by synthesizing the output image data with the dot ratio image data that is the image data representing the original dot ratio, the original dot ratio is calculated from the output image data. Can be read.

  According to the invention described in claim 4, since the dot ratio image data is generated in a form that is difficult to visually recognize when printed out, the dot ratio image data is synthesized with the output image data. As a result, it is possible to suppress degradation of the image quality of the output image.

  According to the fifth aspect of the present invention, since the dot ratio image data is generated in a predetermined color that is difficult to visually recognize, the dot ratio image data that is difficult to visually recognize can be easily generated.

  According to the sixth aspect of the invention, when it is determined that the document image data includes the dot ratio image data, the document dot ratio is obtained, so it is determined whether or not the user is a copy document. It is not necessary to perform an operation such as performing an operation, reducing the user's work load and generating an output image in which the deterioration of the image quality is suppressed using the read document dot ratio.

  According to the seventh aspect of the present invention, it is possible to realize an image forming apparatus capable of suppressing deterioration in image quality associated with generation copying without increasing the user's work load.

  Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a copying machine as an example of an image forming apparatus according to the present invention. The copying machine 1 includes a main unit 200, a sheet post-processing unit 300 disposed on the left side of the main unit 200, an operation unit 400 for a user to input various operation commands and the like, and an upper part of the main unit 200. A document reading unit 500 (corresponding to a part of the document reading unit) provided and a document feeding unit 600 provided above the document reading unit 500 are provided.

  The operation unit 400 includes an operation panel 401, a start key 402, a numeric keypad 403, and the like. The operation panel 401 displays various operation screens and a liquid crystal display (LCD) 401a that displays various operation buttons and the like for the user to input various operation commands, and the LCD 401a. The touch panel 401b and the like disposed on the touch panel. The start key 402 is used for the user to input a print execution command and the like, and the ten key 403 is used for inputting the number of copies to be printed.

  The touch panel 401b is a rectangular thin layered body, and is configured by covering with a transparent cover a pressure-sensitive material made of a linear transparent material at predetermined pitches in the vertical and horizontal directions, on the screen of the LCD 401a. It is affixed to. And it is comprised so that it can determine which button was instruct | indicated from the address and press position of a button which urges selection etc. which are displayed on the LCD 401a screen.

  The document feeding unit 600 includes a document placement unit 601, a document discharge unit 602, a paper feed roller 603, a document transport path 604, a contact glass 605, and the like, and the document reading unit 500 includes a scanner 501 and the like.

  The paper feed roller 603 feeds out the original set on the original placement unit 601, and the original conveyance path 604 conveys the delivered original one by one on the scanner 501 one by one. The scanner 501 includes an imaging device (CCD; Charge Coupled Device), and sequentially reads the conveyed document. The read document is discharged to the document discharge unit 602. The scanner 501 reads a document while moving in the direction indicated by the arrow A (right direction in the drawing) along the contact glass 605 when reading the document placed on the contact glass 605.

  The main body 200 includes a plurality of (here, three) paper feed cassettes 201a to 201c, a plurality of (here, three) paper feed rollers 202a to 202c, a manual paper feed unit 201d, and a manual paper feed roller 202d. , Transfer roller 203, intermediate transfer roller 204, photosensitive drum 205, exposure device 206, developing devices 207Y and 207M for developing colors of yellow (Y), magenta (M), cyan (C), and black (K). 207C, 207K, a fixing roller 208, a discharge port 209, a discharge tray 210, a recording paper conveyance path 211, and the like.

  The photosensitive drum 205 is uniformly charged by a charging device (not shown) while rotating in the direction of the arrow. The exposure device 206 converts the modulation signal generated based on the image data of the original read by the original reading unit 500 into a laser beam and outputs it, and forms an electrostatic latent image on the photosensitive drum 205 for each color. It is. The developing devices 207Y, 207M, 207C, and 207K supply the respective color developers to the photosensitive drum 205 to form toner images for the respective development colors. The intermediate transfer roller 204 is configured to transfer a toner image of each development color from the photosensitive drum 205 and form a color toner image on the intermediate transfer roller 204.

  On the other hand, the paper feeding rollers 202a to 202c pull out the recording paper from the paper feeding cassettes 201a to 201c in which the recording paper is stored, and the recording paper conveyance path 211 conveys the drawn recording paper to the transfer roller 203. is there. The transfer roller 203 transfers the toner image on the intermediate transfer body roller 204 to the conveyed recording paper. The recording paper onto which the toner image has been transferred is conveyed to the fixing roller 208 through the recording paper conveyance path 211, and the fixing roller 208 heats the transferred toner image to fix it on the recording paper. The recording sheet on which the toner image is fixed is conveyed to the discharge port 209 via the recording sheet conveyance path 211 and is carried into the sheet post-processing unit 300. The recording paper is also discharged to the discharge tray 210 as necessary.

  The paper post-processing unit 300 includes a carry-in port 301, a recording paper conveyance path 302, a carry-out port 303, a stack tray 304, and the like. The recording paper conveyance path 302 sequentially conveys the recording paper carried into the carry-in port 301 from the discharge port 209 and finally discharges the recording paper from the carry-out port 303 to the stack tray 304. The stack tray 304 is configured to move up and down in the direction of the arrow in accordance with the number of recording sheets stacked from the carry-out port 303.

  FIG. 2 is a block diagram showing an example of a functional configuration of the control unit of the copying machine 1 shown in FIG. The copying machine 1 includes a control unit 700 that is disposed at an appropriate position of the copying machine 1 and controls the operation of the copying machine 1. Here, the control unit 700 includes a CPU (Central Processing Unit) 710, a RAM (Random Access Memory) 720 used as a work area of the CPU, and a ROM (Read Only Memory) that stores an image processing program according to the present invention. (Omitted).

  The CPU 710 reads an original image via the scanner 501 shown in FIG. 1 or the like and generates an original image data (corresponding to a part of the original reading means), and the original image data includes dot ratio image data. A document image determination unit 712 (corresponding to a document image determination unit) that determines whether or not the document dot ratio is included, and a document dot reading unit that determines the document dot ratio when it is determined that the dot ratio image data is included. 713 (corresponding to document dot reading means), an output image generating unit 714 (corresponding to output image generating means) that reads document image data and generates output image data that is image data for print output, and output Dot ratio calculation that calculates the ratio of the number of dots for each specified development color of the output image data to the total number of dots contained in the image data as the output dot ratio 715 (corresponding to the dot ratio calculating means), an image correcting unit 716 (corresponding to the image correcting means) for correcting the output image data based on the output dot ratio and the document dot ratio, and image data representing the document dot ratio. A dot ratio image generation unit 717 (corresponding to dot ratio image generation means) that generates certain dot ratio image data, and an image combination unit 718 (synthesizing the dot ratio image data with the output image data to further correct the output image data) And a printing unit 719 (corresponding to printing means) that forms output image data as an image on recording paper.

  The RAM 720 includes a document image storage unit 721 (corresponding to a document image storage unit) that stores document image data generated by the document reading unit 711, and a dot ratio that stores the document dot ratio obtained by the document dot reading unit 713. And a storage unit 722 (corresponding to dot ratio storage means).

  Here, the CPU reads and executes an image processing program according to the present invention stored in advance in a ROM or the like, whereby a document reading unit 711, a document image determination unit 712, a document dot reading unit 713, and an output image generation unit 714. It functions as a functional unit such as the dot ratio calculation unit 715.

  Further, among various data stored in the RAM 720 and ROM, data that can be stored in a removable recording medium is read by a driver such as a hard disk drive, an optical disk drive, a flexible disk drive, a silicon disk drive, or a cassette medium reader. In this case, the recording medium is, for example, a hard disk, an optical disk, a flexible disk, a CD, a DVD, a semiconductor memory, or the like.

  A document reading unit 711 reads a color document image via the scanner 501 shown in FIG. 1 or the like, and reads image data composed of three components R (Red), G (Green), and B (Blue) for each pixel (hereinafter referred to as a document). Image data), and the generated image data is stored in the document image storage unit 721.

  The document image determination unit 712 determines whether or not the document image data includes dot ratio image data that is image data representing the document dot ratio. Here, the original dot ratio refers to the total number of dots within the printed range when the color original is printed (all the dots constituting the image data for print output). This is the ratio of the number of dots for a predetermined development color (here, yellow (Y), magenta (M), cyan (C), black (K)) to the number of dots).

Specifically, the total number of dots DT, the number of dots DY, DM, and DC of the development colors of yellow (Y), magenta (M), cyan (C), and black (K) included in the image data for print output. , DK, the original dot ratios DRY, DRM, DRC, and DRK of the development colors of yellow (Y), magenta (M), cyan (C), and black (K) are the following (1) to (4 ) Expression.
DRY = DY / DT × 100 (1)
DRM = DM / DT × 100 (2)
DRC = DC / DT × 100 (3)
DRK = DK / DT × 100 (4)

  The document dot reading unit 713 determines the document dot ratios DRY, DRM, DRC, and DRK from the dot ratio image data when the document image determination unit 712 determines that the dot ratio image data is included in the document image data. The obtained document dot ratios DRY, DRM, DRC, and DRK are stored in the dot ratio storage unit 722.

  The output image generation unit 714 reads the document image data from the document image storage unit 721, and prints output data composed of development colors of yellow (Y), magenta (M), cyan (C), and black (K). The output image data, which is the image data, is generated.

The dot ratio calculation unit 715 calculates the ratio of the number of dots for each development color of the output image data to the total number of dots included in the output image data as the output dot ratio. Specifically, the total number of dots PDT of the output image data, the number of dots PDY, PDM of the development colors of yellow (Y), magenta (M), cyan (C), and black (K) included in the output image data, Using PDC and PDK, the output dot ratios PRY, PRM, PRC, and PRK of the development colors of yellow (Y), magenta (M), cyan (C), and black (K) are the following (5) to ( 8) It is expressed by the formula.
PRY = PDY / PDT × 100 (5)
PRM = PDM / PDT × 100 (6)
PRC = PDC / PDT × 100 (7)
PRK = PDK / PDT × 100 (8)

  The image correction unit 716 sets the output dot ratios PRY, PRM, PRC, and PRK to the original dot ratios DRY, DRM, and DRC for each development color of yellow (Y), magenta (M), cyan (C), and black (K). The output image data is corrected so as to substantially match the DRK.

Here, the output image data is repeatedly corrected until the evaluation index DP defined by the following equation (9) becomes equal to or less than a predetermined threshold SH.
DP = (PRY−DRY) ² + (PRM−DRM) ² + (PRC−DRC) ² + (PRK−DRK) ² (9)
The output image data is corrected by, for example, γ correction.

  The dot ratio image generation unit 717 generates dot ratio image data that is image data representing the document dot ratios DRY, DRM, DRC, and DRK. Here, the dot ratios DRY, DRM, DRC, and DRK are associated with symbols (Y, M, C, and K) representing each development color in a predetermined color that is difficult to visually recognize (for example, light yellow). Is generated as a numerical value at a predetermined position (see FIG. 3).

  The image synthesis unit 718 further corrects the output image data by synthesizing the dot ratio image data with the output image data corrected by the image correction unit 716. Here, an example of the synthesis process of the output image data and the dot ratio image data will be described with reference to FIG.

  FIG. 3 is an explanatory diagram illustrating an example of the composition process performed by the image composition unit 718. (A) is an image showing an example of output image data corrected by the image correction unit 716, (b) is an image showing an example of dot ratio image data, and (c) is an output image data and This is an image synthesized with dot ratio image data.

  As shown in (a), the output image 801 is formed with development colors of yellow (Y), magenta (M), cyan (C), and black (K) in an area 800 corresponding to a predetermined recording sheet. It is an image (in the figure, the output image 801 is displayed as a monochrome image for convenience).

  As shown in (b), the dot ratio image 811 is formed in light yellow (Y) in an area 810 corresponding to a predetermined recording sheet, and has symbols (Y, M, C, K) representing the development colors. Correspondingly, the dot ratios DRY, DRM, DRC, and DRK are numerical values, and the images are formed at predetermined positions (here, substantially the center of the region 810) (in the figure, the output image 801 is monochrome for convenience). Is displayed as an image).

  As shown in (c), the dot ratio image 811 shown in (b) is combined with the output image 801 shown in (a) and corrected. Here, for the sake of convenience, the dot ratio image 822 is displayed in a form that can be visually recognized, but since it is formed with light yellow (Y), which is difficult to visually recognize, the actual image is ( The difference between the output image 801 shown in a) and the output image 821 shown in (c) (the presence or absence of the dot ratio image 822) is so slight that it can hardly be discerned visually.

  Returning to FIG. 2 again, the functional configuration of the control unit will be described. The printing unit 719 forms the output image data corrected by the image composition unit 718 as an image on a recording sheet. Specifically, in order to print the output image data corrected by the image composition unit 718 on a recording sheet, the transfer roller 203, the intermediate transfer member roller 204, the photosensitive drum 205, and the exposure that constitute the main body 200 shown in FIG. An instruction signal is output to the device 206, the developing devices 207Y, 207M, 207C, 207K, the fixing roller 208, and the like.

  The document image storage unit 721 stores document image data composed of R, G, and B components generated by the document reading unit 711, and the dot ratio storage unit 722 is obtained by the document dot reading unit 713. The original dot ratios DRY, DRM, DRC, DRK are stored.

  FIG. 4 is a flowchart illustrating an example of an operation for reading a document image of the control unit 700. First, a document image is read by the document reading unit 711 via the scanner 501 shown in FIG. 1 or the like, and document image data is generated (step S101). Then, the document image determination unit 712 determines whether or not the dot ratio image data is included in the document image data (step S103). If it is determined that the dot ratio image data is not included (NO in step S103), the process proceeds to step S109.

  If it is determined that the dot ratio image data is included (YES in step S103), the document dot reading unit 713 obtains the document dot ratios DRY, DRM, DRC, and DRK from the dot ratio image data (step S103). In step S105, the obtained document dot ratios DRY, DRM, DRC, and DRK are stored in the dot ratio storage unit 722 (step S107). When the process in step S107 is completed, or if NO in step S103, the document reading unit 711 stores the document image data in the document image storage unit 721 (step S109), and the process ends.

  FIG. 5 is a flowchart illustrating an example of the printing operation of the control unit 700. First, the output image generation unit 714 generates output image data that is image data for print output (step S201). Then, the dot ratio calculation unit 715 obtains output dot ratios PRY, PRM, PRC, and PRK of the output image data (step S203). Next, the image correction unit 716 reads the document dot ratios DRY, DRM, DRC, and DRK from the dot ratio storage unit 722 (step S205), and sets the output dot ratios PRY, PRM, PRC, and PRK to the document dot ratios DRY, DRM. The output image data is corrected so as to substantially match DRC and DRK (step S207). Next, the dot ratio calculation unit 715 obtains the output dot ratios PRY, PRM, PRC, and PRK for the corrected output image data (step S209).

  Then, the image correction unit 716 calculates the evaluation index DP using the above-described equation (9), and determines whether or not the calculated evaluation index DP is equal to or less than the threshold value SH (step S211). If it is determined that the evaluation index DP is not less than or equal to the threshold value SH (greater than the threshold value SH) (NO in step S211), the process returns to step S207, and the processes in and after step S207 are repeatedly executed.

  If it is determined that the evaluation index DP is equal to or less than the threshold SH (YES in step S211), the dot ratio image generation unit 717 performs dot ratio image that is image data representing the document dot ratios DRY, DRM, DRC, and DRK. Data is generated (step S213). Then, the image composition unit 718 synthesizes the dot ratio image data generated in step S213 with the output image data corrected in step S207 to further correct the output image data (step S215). Then, the output image data combined with the dot ratio image data in step S215 is printed (step S217), and the process ends.

  As described above, the output dot ratios PRY, PRM, PRC, PRK defined by the expressions (5) to (8) and the original dot ratio defined by the expressions (1) to (4) by the image correcting unit 716. Since the output image data is corrected based on DRY, DRM, DRC, and DRK, it is possible to suppress deterioration in image quality associated with generation copying without increasing the user's work load.

  Further, the image correction unit 716 converts the output dot ratios PRY, PRM, PRC, and PRK to the original dot ratios DRY, DRM for each development color of yellow (Y), magenta (M), cyan (C), and black (K). Since the output image data is corrected so as to substantially match the DRC and DRK, the color tone of the entire output image is matched with the color tone of the entire original image, and the deterioration in image quality due to the generation copy is further suppressed.

  Further, since the image composition unit 718 combines the output image data with the dot ratio image data that is the image data representing the document dot ratio and the output image data is corrected, the document dot ratio can be read from the output image data. It becomes possible.

  In addition, since the dot ratio image generation unit 717 generates dot ratio image data in a form that is difficult to visually recognize when printed out, the dot ratio image data is combined with the output image data by the image combining unit 718. As a result, the image quality of the output image is prevented from deteriorating.

  In addition, since the dot ratio image generation unit 717 generates the dot ratio image data in a predetermined color that is difficult to visually recognize (here, light yellow (Y)), the dot ratio image data that is difficult to visually recognize. Is easily generated.

  Further, when the document image determining unit 712 determines that the dot image data is included in the document image data, the document dot reading unit 713 calculates the document dot ratios DRY, DRM, DRC, and DRK. It is not necessary for the user to perform operations such as determining whether or not the document is a copy document, the user's work load is reduced, and image quality degradation is caused by using the read document dot ratios DRY, DRM, DRC, and DRK. It is possible to generate an output image in which is suppressed.

  In addition, this invention can take the following aspects.

  (A) In the present embodiment, the case where the image forming apparatus is the copying machine 1 has been described. However, another type of image forming apparatus (for example, a facsimile, a printer, or the like) may be used.

  For example, when the image forming apparatus is a printer that is communicably connected to a personal computer, the original dot ratios DRY, DRM, DRC, and DRK may be received from the personal computer together with the original image data.

  (B) In this embodiment, the image correction unit 716 corrects the output image data so that the output dot ratios PRY, PRM, PRC, and PRK of the output image data substantially match the original dot ratios DRY, DRM, DRC, and DRK. However, when the total number of dots of the output image data and the document image data substantially match, the number of dots of each development color of the output image is substantially matched to the number of dots of each development color of the document image. The output image data may be corrected as much as possible.

  In this case, it is preferable that the image synthesis unit 718 synthesizes image data representing the number of dots of each development color of the document image with the output image data.

  (C) In this embodiment, the image correction unit 716 corrects the output image data so that the output dot ratios PRY, PRM, PRC, and PRK of the output image data substantially match the original dot ratios DRY, DRM, DRC, and DRK. The output image data is corrected so that the output dot ratios PRY, PRM, PRC, and PRK of the output image data have a predetermined relationship with the original dot ratios DRY, DRM, DRC, and DRK. That's fine.

For example, the ratio of the density of one dot of each development color of yellow (Y), magenta (M), cyan (C), and black (K) of the output image to the density of one dot of each corresponding development color of the original image Is 2: 1: 1: 1, the evaluation index DP may be defined by the following equation (10) instead of the above equation (9).
DP = (PRY / 2−DRY) ² + (PRM−DRM) ² + (PRC−DRC) ² + (PRK−DRK) ² (10)
That is, the evaluation index DP may be set in consideration of characteristics such as the density of one dot of each development color of the output image and the original image.

  (D) In the present embodiment, the dot ratio image generation unit 717 is light yellow and is associated with symbols (Y, M, C, K) representing the development colors, and the dot ratios DRY, DRM, DRC, Although the case where DRK is generated as a numerical value at a predetermined position has been described, the dot ratio image data may be generated in other forms that are difficult to visually recognize.

  For example, a bar code representing the document dot ratios DRY, DRM, DRC, and DRK may be generated at a predetermined position (for example, lower right). In this case, any form that uses at least one of a position, a size, and a color for generating an image may be used so that the form is difficult to visually recognize.

  (E) In the present embodiment, the case where the image composition unit 718 composites the dot ratio image data representing the document dot ratios DRY, DRM, DRC, and DRK with the output image data has been described. For example, the dot ratio image data may be printed (for example, at another position). In this case, the deterioration of image quality due to the synthesis of the dot ratio image data is eliminated.

1 is a side view of a copying machine as an example of an image forming apparatus according to the present invention. FIG. 2 is a block diagram illustrating an example of a functional configuration of a control unit of the copier illustrated in FIG. 1. It is explanatory drawing which shows an example of the synthetic | combination process performed in an image synthetic | combination part. 6 is a flowchart illustrating an example of an operation of reading a document image of a control unit. It is a flowchart which shows an example of the printing operation of a control part.

Explanation of symbols

1 Copying machine (image forming device)
200 Main Body 300 Paper Post-Processing Unit 400 Operation Unit 500 Document Reading Unit 600 Document Feeding Unit 700 Control Unit 710 CPU
711 Document reading unit (document reading means)
712 Document image determination unit (document image determination means)
713 Document Dot Reading Unit (Document Dot Reading Unit)
714 Output image generation unit (output image generation means)
715 dot ratio calculation unit (dot ratio calculation means)
716 Image correction unit (image correction means)
717 dot ratio image generator (dot ratio image generator)
718 Image composition unit (image composition means)
719 Printing section (printing means)
720 RAM
721 Document image storage unit (document image storage means)
722 dot ratio storage unit (dot ratio storage means)

Claims (8)

Output color image data for printing out from original image data, which is image data generated by optically reading and photoelectrically converting a color original printed on a recording sheet with a predetermined developing color in advance by one image forming apparatus. An image processing apparatus for generating image data,
Document image storage means for storing the document image data;
Dot ratio storage means for storing, as a document dot ratio, a ratio of the number of dots for each predetermined development color to the total number of dots in the printed range when the color document is printed by the image forming apparatus of the first aspect; ,
Output image generation means for reading the original image data from the original image storage means and generating the output image data composed of the predetermined development color;
Dot ratio calculating means for determining, as an output dot ratio, a ratio of the number of dots for each predetermined development color of the output image data to the total number of dots included in the output image data;
An image processing apparatus comprising: an image correcting unit that corrects the output image data based on the output dot ratio and the document dot ratio.   The image processing apparatus according to claim 1, wherein the image correction unit corrects the output image data so that the output dot ratio substantially matches the original dot ratio for each of the predetermined development colors. Dot ratio image generation means for reading the original dot ratio stored in the dot ratio storage means and generating dot ratio image data which is image data representing the original dot ratio;
3. The image processing according to claim 1, further comprising: an image combining unit that combines the dot ratio image data with the output image data corrected by the image correcting unit to further correct the output image data. apparatus.   The image processing apparatus according to claim 3, wherein the dot ratio image generation unit generates the dot ratio image data in a form that is difficult to visually recognize when printed out.   The image processing apparatus according to claim 4, wherein the dot ratio image generation unit generates the dot ratio image data in a predetermined color that is difficult to visually recognize. Document image determination means for determining whether or not the dot ratio image data is included in the document image data;
6. A document dot reading means for obtaining said document dot ratio and storing it in said dot ratio storage means when it is determined that said dot ratio image data is included. The image processing apparatus according to any one of the above. An image processing device according to any one of claims 1 to 6,
A document reading means for optically reading a document image and photoelectrically generating the document image data;
An image forming apparatus comprising: a printing unit that forms the output image data as an image on a recording sheet. An image for printing output from original image data which is image data generated by optically reading and photoelectrically converting a color original printed in advance with a predetermined developing color on a recording paper by one image forming apparatus. An image processing apparatus for generating output image data which is data, the computer comprising:
Document image storage means for storing the document image data;
Dot ratio storage means for storing, as a document dot ratio, a ratio of the number of dots for each predetermined development color to the total number of dots in the printed range when the color document is printed by the image forming apparatus of the first aspect; ,
Output image generation means for reading the original image data from the original image storage means and generating the output image data composed of the predetermined development color;
Dot ratio calculating means for determining, as an output dot ratio, a ratio of the number of dots for each predetermined development color of the output image data to the total number of dots included in the output image data;
An image processing program that functions as an image correction unit that corrects the output image data based on the output dot ratio and the document dot ratio.

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