Image forming apparatus, image forming method, and program

Abstract

To provide an image forming apparatus that can prevent a phenomenon in which a character and a ruled line on a colored background look thicker than a character and a ruled line on an uncolored background.SOLUTION: An image forming apparatus comprises: an image forming unit that attaches a coloring material to a sheet for each of a plurality of pixels arranged side by side in a first direction; a sheet conveying unit that conveys the sheet in a second direction; a determination unit that determines whether a first coloring material used for a first pixel of the plurality of pixels, and a second coloring material used for a second pixel located on a rear end side in the second direction relative to the first pixel and adjacent to the first pixel, are the same or not; and a correction unit that, when the first coloring material and the second coloring material are determined to be the same, the concentration of the first coloring material is lower than a first concentration, and the concentration of the second coloring material is a second concentration equal to or more than the first concentration, executes correction processing of correcting the concentration of the first coloring material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to an image forming apparatus, an image forming method, and a program. This application claims priority to Japanese Patent Application No. 2024-025040, filed February 22, 2024, the contents of which are incorporated herein by reference. [Background technology]

[0002] Patent Document 1 discloses an image forming apparatus that can change the drawing conditions for ruled lines included in print data and output the data based on a user operation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-192015 Summary of the Invention [Problem to be solved by the invention]

[0004] Characters or lines on a colored background may appear thicker than characters or lines on an uncolored area. The image forming device disclosed in Patent Document 1 does not allow for the thickness of characters and lines on a colored background to be adjusted by specifying the characters and lines. Even when the image forming device disclosed in Patent Document 1 changes the drawing conditions for the lines and outputs the image, the characters or lines on a colored background may appear thicker than the characters or lines on an uncolored area. Therefore, one aspect of the present disclosure aims to provide an image forming device, an image forming method, and a program that can suppress the phenomenon in which characters and lines on a colored background appear thicker than the characters and lines on an uncolored area. [Means for solving the problem]

[0005] An image forming apparatus according to one embodiment of the present disclosure includes an image forming unit that applies coloring material to paper for each of a plurality of pixels arranged in a first direction; a paper transport unit that transports the paper in a second direction; a determination unit that determines whether a first coloring material used for a first pixel among the plurality of pixels is the same as a second coloring material used for a second pixel that is on the rear end side of the first pixel in the second direction and adjacent to the first pixel; and a correction unit that performs a correction process to correct the concentration of the first coloring material when it is determined that the first coloring material and the second coloring material are the same, the concentration of the first coloring material is lower than a first concentration, and the concentration of the second coloring material is equal to or higher than a second concentration that is equal to or higher than the first concentration.

[0006] An image forming method according to one embodiment of the present disclosure includes a step of determining whether a first colorant used for a first pixel among a plurality of pixels aligned in a first direction is the same as a second colorant used for a second pixel that is at the rear end side of the first pixel in a second direction; a step of performing a correction process to correct the density of the first colorant when it is determined that the first colorant and the second colorant are the same, and the density of the first colorant is lower than a first density and the density of the second colorant is equal to or higher than a second density that is equal to or higher than the first density; a step of applying colorant to paper for each of a plurality of pixels aligned in the first direction; and a step of transporting the paper in the second direction.

[0007] A program according to one embodiment of the present disclosure causes a computer that controls an image forming device having an image forming unit that applies coloring material to paper for each of a plurality of pixels arranged in a first direction and a paper transport unit that transports the paper in a second direction to perform the following functions: determining whether a first coloring material used for a first pixel of the plurality of pixels is the same as a second coloring material used for a second pixel that is on the trailing end side of the first pixel in the second direction; and performing a correction process to correct the concentration of the first coloring material when it is determined that the first coloring material and the second coloring material are the same, the concentration of the first coloring material is lower than a first concentration, and the concentration of the second coloring material is equal to or higher than a second concentration that is equal to or higher than the first concentration. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of a configuration of an image forming apparatus. [Figure 2] FIG. 2 is a diagram for explaining the operation of an image forming unit. [Figure 3] 3 is a diagram showing an example of the positions of a first pixel, a second pixel, a first region, and a second region. FIG. [Figure 4] 5 is a flowchart illustrating an example of an operation of the image forming apparatus according to the first embodiment. [Figure 5A] FIG. 10 is a diagram showing an example of an area including a linear object and a background of the linear object. [Figure 5B] 5B is a diagram showing an example of the densities of coloring materials used for pixels in the region shown in FIG. 5A. FIG. [Figure 6A] FIG. 10 is a diagram showing an example of an area including a linear object and a background of the linear object. [Figure 6B] 6B is a graph showing an example of the density of color materials after correction for pixels in the region illustrated in FIG. 6A. [Figure 6C] FIG. 6C is a diagram showing an example of an image after correction illustrated in FIG. 6B. [Figure 6D] 6B is a graph showing an example of the density of color materials after correction for pixels in the region illustrated in FIG. 6A. [Figure 6E] FIG. 6E is a diagram showing an example of an image after correction illustrated in FIG. 6D. [Figure 7] 10 is a flowchart illustrating an example of an operation of an image forming apparatus according to a third embodiment. [Figure 8] FIG. 10 is a diagram showing an example of a case where the density of the color material is reduced for a plurality of pixels included in the first region when one color of color material is used for the first pixel. [Figure 9] FIG. 10 is a diagram showing an example of a case where the density of the color material is reduced for a plurality of pixels included in the first region when more than one color of color material is used for the first pixel. [Figure 10] 10 is a flowchart illustrating an example of an operation of an image forming apparatus according to a fourth embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the process of step S1008 illustrated in FIG. [Figure 12] FIG. 10 is a diagram illustrating an example of a first concentration and a second concentration. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) The first embodiment will be described with reference to Figures 1 to 5B. Note that in the drawings, the same or equivalent elements are given the same reference numerals, and redundant explanations will be omitted.

[0010] Image data 111 handled by image forming apparatus 100 corresponds to a color image using the colors black (K), cyan (C), magenta (M), and yellow (Y). The image data 111 indicates pixel value information. The pixel value information indicates the coordinate values ​​and pixel values ​​of each of the multiple pixels indicated by the image data 111.

[0011] 1 is a block diagram showing an example of the configuration of an image forming apparatus 100. The image forming apparatus 100 includes a storage unit 101, an operation unit 102, a display unit 103, an image acquisition unit 104, an image forming unit 105, a paper conveyance unit 106, an image output unit 107, and a control unit 108.

[0012] The storage unit 101 is a recording medium capable of recording various data, programs, etc. The storage unit 101 is configured by, for example, one or more hard disk drives (HDDs), one or more solid state drives (SSDs), one or more semiconductor memories, etc.

[0013] The operation unit 102 accepts operations by a user. For example, the operation unit 102 accepts an operation to select a function installed in the image forming apparatus 100 and an operation to specify the number of copies to be printed. The operation unit 102 is composed of a touch panel, a mouse, a keyboard, etc.

[0014] The display unit 103 displays information to be presented to the user. For example, the display unit 103 is configured with a liquid crystal panel, an organic EL (Electro-Luminescence) panel, or the like.

[0015] The image acquiring unit 104 acquires image data 111. For example, the image acquiring unit 104 reads an original placed on an original placing table (not shown) and acquires image data 111 indicating the read original. Alternatively, the image acquiring unit 104 acquires the image data 111 by receiving image data 111 transmitted from a terminal device (not shown) connected to the image forming apparatus 100 via a network. For example, the terminal device is a PC (Personal Computer), a smartphone, a tablet terminal, etc.

[0016] The image forming unit 105 applies color material to the paper 201 (see FIG. 2) in a first direction D1 (see FIG. 3) to form an image based on the image data 111. For example, the image forming unit 105 is configured as a laser printer that uses an electrophotographic method, and applies toner, which is a color material, to the paper 201 to form an image on the paper 201.

[0017] The image forming unit 105 includes a photosensitive drum 121, a transfer belt 122, and the like.

[0018] The image forming unit 105 exposes the charged photosensitive drum 121 in accordance with the image data 111, thereby forming an electrostatic latent image on the surface of the photosensitive drum 121 in accordance with the image data 111. The image forming unit 105 visualizes the electrostatic latent image formed on each photosensitive drum 121 with four colors (KCMY) of toner TK (see FIG. 2), TC (see FIG. 2), TM (see FIG. 2), and TY (see FIG. 2).

[0019] Four photosensitive drums 121 are provided for each color to form four types of latent images, one for black, one for cyan, one for magenta, and one for yellow, and these constitute four image stations.

[0020] The toner images of each color, which are visualized by the toner adhering to the electrostatic latent images formed on the photosensitive drums 121, are layered on the transfer belt 122. The layered toner images are transferred onto the paper 201 as the transfer belt 122 rotates.

[0021] The paper transport unit 106 transports the paper 201, on which an image based on image data 111 has been formed by the image forming unit 105, in a second direction D2 (see FIGS. 2 and 3). The paper transport unit 106 is configured with rollers and / or belts for transporting the paper 201.

[0022] The image output unit 107 outputs the paper 201 on which the image based on the image data 111 has been formed by the image forming unit 105 from a paper discharge outlet (not shown).

[0023] The control unit 108 controls the entire image forming apparatus 100. The control unit 108 realizes various functions by reading and executing various programs stored in the storage unit 101. The control unit 108 may be realized by one or more control devices / arithmetic units (CPUs (Central Processing Units), SoCs (System on a Chip)), one or more RAMs (Random Access Memories), one or more ROMs (Random Access Memories), various interface circuits, etc. Furthermore, some or all of the processing units included in the control unit 108 may be configured with electronic circuits. The control unit 108 includes a determination unit 109 and a correction unit 110. The determination unit 109 and the correction unit 110 are realized by the control unit 108 reading and executing various programs stored in the storage unit 101.

[0024] The determination unit 109 determines whether a first color material used for a first pixel P1 (see FIG. 3) indicated by image data 111 is the same as a second color material used for a second pixel P2 (see FIG. 3) adjacent to the rear end side of the first pixel P1 in the second direction D2. The first color material and the second color material being the same means that the combination of color components used for the first pixel P1 is the same as the combination of color components used for the second pixel P2.

[0025] The correction unit 110 executes a correction process when it is determined that the first color material and the second color material are the same, the density of the first color material is lower than the first density (see FIG. 12), and the density of the second color material is equal to or greater than the second density (see FIG. 12), which is equal to or greater than the first density. The first density and the second density are predetermined densities. For example, the difference between the first density and the second density is greater than a predetermined density difference. Also, for example, it is assumed that the first density and the second density are maximum densities. In this case, if the determination unit 109 determines that the first color material and the second color material are the same, the first color material is not at its maximum density, and the second color material is at its maximum density, the correction unit 110 executes a correction process to correct the density of the first color material. Specifically, the correction process is performed by the correction unit 110 to reduce the density of the first color material.

[0026] FIG. 2 is a diagram for explaining the operation of the image forming unit 105. As shown in FIG.

[0027] The transfer belt 122 is provided so as to contact each photosensitive drum 121. As the transfer belt 122 rotates, the toner images of the colors K, C, M, and Y formed on the photosensitive drums 121 are transferred onto the transfer belt 122 in a sequentially overlapping manner. This forms a color toner image on the transfer belt 122. The toner images are transferred onto the paper 201 by the rotation of the transfer belt 122. As a result, the image forming unit 105 attaches color material to the paper 201 for each of a plurality of pixels aligned in the first direction D1 (see FIG. 3). Then, the paper transport unit 106 transports the paper 201 in the second direction D2, and the image forming unit 105 forms a new toner image on the transfer belt 122. The new toner image is then transferred onto the paper 201 in the first direction D1 by the rotation of the transfer belt 122.

[0028] FIG. 3 is a diagram showing an example of the positions of a first pixel P1, a second pixel P2, a first region R1, and a second region R2. The second pixel P2 is adjacent to the first pixel P1. The second region R2 includes the second pixel P2 and is a linear region extending in the first direction D1. The first region R1 includes the second pixel P2 and is adjacent to the second region R2. FIG. 3 illustrates one first pixel P1 and one second pixel P2, but the first pixel P1 may be adjacent to each of multiple second pixels P2 included in the second region R2. In other words, when multiple second pixels P2 are lined up in the first direction D1, multiple first pixels P1 may be lined up along the multiple second pixels P2.

[0029] FIG. 4 is a flowchart showing an example of the operation of the image forming apparatus 100 according to this embodiment.

[0030] In step S401, the image acquisition unit 104 acquires the image data 111.

[0031] In step S402, the determination unit 109 selects a first pixel P1 included in the first region R1 from among the plurality of pixels indicated by pixel value information indicated by the acquired image data 111. For example, the determination unit 109 sequentially scans the plurality of pixels indicated by the pixel value information indicated by the image data 111 and sequentially selects the first pixel P1 from the plurality of pixels. Alternatively, for example, the determination unit 109 identifies a linear object along the first direction D1 from an image based on the image data 111. For example, the linear object is a character or a ruled line. Then, the determination unit 109 selects a first pixel P1 from among the plurality of pixels included in the first region R1 that is adjacent in the second direction D2 to the second region R2 indicating the identified linear object.

[0032] In step S403, the determination unit 109 determines whether the first color material used for the selected first pixel P1 is the same as the second color material used for the second pixel P2 included in the second region R2. Specifically, the determination unit 109 determines whether the combination of color components used for the first pixel P1 is the same as the combination of color components used for the second pixel P2.

[0033] For example, suppose that the first color material uses a color component that is black (K), and does not use color components that are cyan (C), magenta (M), and yellow (Y). Also, suppose that the second color material uses a color component that is black (K), and does not use color components that are cyan (C), magenta (M), and yellow (Y). In this case, the determining unit 109 determines that the first color material and the second color material are the same.

[0034] Also, for example, suppose that the color component black (K) is used as the first color material, and the color components cyan (C), magenta (M), and yellow (Y) are not used. On the other hand, suppose that the color components black (K) and cyan (C) are used as the second color material, and the color components magenta (M) and yellow (Y) are not used. In this case, the determining unit 109 determines that the first color material and the second color material are not the same.

[0035] If the first color material and the second color material are not the same in step S403, the control unit 108 returns the process to step S402. That is, the determination unit 109 selects a new first pixel P1 and continues the process.

[0036] On the other hand, if the first colorant and the second colorant are determined to be the same in step S403, the determination unit 109 determines in step S404 whether the density of the second colorant is equal to or greater than the second density. The second density is a predetermined density. For example, the second density is determined according to the specifications of the image forming unit 105. Specifically, the second density is determined according to the amount of correction for the surface potential of the photosensitive drum 121, the amount of correction for the voltage value in the process of visualizing the electrostatic latent image formed on the photosensitive drum 121, the current value in the process of transferring the visualized toner images of each color to the transfer belt 122, etc. Alternatively, the control unit 108 may determine the second density according to the distribution of multiple pixel values ​​included in the image based on the image data 111. For example, the second density is the maximum density. In this case, the determination unit 109 determines in step S404 whether the density of the second colorant is the maximum density. Specifically, when the densities of all color components used in the second color material are the maximum densities, the determining unit 109 determines that the density of the second color material is the maximum density.

[0037] For example, if the density of black (K) among the multiple color components of the second color material is 100%, the density of cyan (C) is 0%, the density of magenta (M) is 0%, and the density of yellow (Y) is 0%, it is determined that the density of the second color material is maximum.Alternatively, if the density of black (K) among the multiple color components of the second color material is 100%, the density of cyan (C) is 100%, the density of magenta (M) is 0%, and the density of yellow (Y) is 0%, it is determined that the density of the second color material is maximum.

[0038] If the density of the second coloring material is not equal to or greater than the second density in step S404, the control unit 108 returns the process to step S402. For example, assume that the second density is the maximum density. In this case, if the density of the second coloring material is not the maximum density in step S404, the control unit 108 returns the process to step S402. That is, the determination unit 109 selects a new first pixel P1 and continues the process.

[0039] On the other hand, if the density of the second colorant is equal to or greater than the second density in step S404, the determination unit 109 determines in step S405 whether the density of the first colorant is lower than the first density. The first density is a predetermined density. For example, the first density is determined according to the specifications of the image forming unit 105. Specifically, the first density is determined according to the correction amount for the surface potential of the photosensitive drum 121, the correction amount for the voltage value in the process of visualizing the electrostatic latent image formed on the photosensitive drum 121, the current value in the process of transferring the visualized toner images of each color to the transfer belt 122, etc. Alternatively, the control unit 108 may determine the first density according to the distribution of multiple pixel values ​​included in the image based on the image data 111. Furthermore, the control unit 108 may determine the first density and the second density so that the difference between the first density and the second density is greater than a predetermined density difference. For example, the first density is the maximum density. In this case, if the density of the second colorant is the maximum density in step S404, the determination unit 109 determines whether the density of the first colorant is lower than the maximum density in step S405. If the densities of all color components in the first colorant are not the maximum density, the determination unit 109 determines that the density of the first colorant is lower than the maximum density.

[0040] For example, if the density of black (K), cyan (C), magenta (M), and yellow (Y) among the multiple color components of the first color material is 80%, 0%, 0%, cyan (C), magenta (M), and yellow (Y), respectively, the density of the first color material is determined to be lower than the maximum density. Alternatively, if the density of black (K), cyan (C), magenta (M), and yellow (Y) among the multiple color components of the first color material used for the first pixel P1 is 80%, 20%, 0%, and 0%, respectively, the density of the first color material C1 is determined to be lower than the maximum density.

[0041] On the other hand, when the densities of all color components of the first color material are the maximum densities, the determination unit 109 determines that the densities of the first color material are the maximum densities. For example, when the density of black (K), cyan (C), magenta (M), and yellow (Y) is 100%, 0%, 0%, and 0%, respectively, of the color components used for the first color material used for the first pixel P1, the determination unit 109 determines that the densities of the first color material are the maximum densities.

[0042] If the density of the first coloring material is equal to or greater than the first density in step S405, the control unit 108 returns the process to step S402. For example, assume that the first density is the maximum density. In this case, if the density of the first coloring material is the maximum density in step S405, the control unit 108 returns the process to step S402. That is, the determination unit 109 selects a new first pixel P1 and continues the process.

[0043] On the other hand, if the density of the first colorant is lower than the first density in step S405, the correction unit 110 corrects the pixel value of the first pixel P1 in step S406. For example, assume that the first density is the maximum density. In this case, if the determination unit 109 determines in step S405 that the density of the first colorant is lower than the maximum density, the correction unit 110 corrects the pixel value of the first pixel P1 in step S406. The correction unit 110 corrects the density of the first colorant by correcting the pixel value of the first pixel P1. Specifically, the correction unit 110 reduces the pixel value of the first pixel P1. The correction unit 110 reduces the density of the first colorant by reducing the pixel value of the first pixel P1.

[0044] In step S407, the correction unit 110 determines whether to end the process of correcting pixel values. For example, if the determination unit 109 has selected all pixels indicated by the pixel value information indicated by the image data 111 as first pixels P1 in step S402, the correction unit 110 determines to end the process of correcting pixel values. Alternatively, if the determination unit 109 has selected all pixels included in a first region R1 adjacent in the second direction D2 to a second region indicating a linear object along the first direction D1 as first pixels P1 in step S402, the correction unit 110 may determine to end the process of correcting pixel values.

[0045] If the correction unit 110 determines not to end the pixel value correction process in step S407, the control unit 108 returns the process to step S402 and continues the process. On the other hand, if the correction unit 110 determines to end the pixel value correction process in step S407, the control unit 108 ends the process.

[0046] Correction of the pixel value of the first pixel P1 in the image forming apparatus 100 according to this embodiment will be described in detail with reference to FIGS. 5A and 5B.

[0047] Fig. 5A is a diagram showing an example of a region 501 including a linear object and the background of the linear object. In this example, a case will be described in which the first density and the second density are maximum densities. Fig. 5A also shows an example of an image IMG including the region 501. The region 501 includes a part of the second region R2 indicating the linear object and a part of the first region R1 indicating the background region.

[0048] FIG. 5B is a diagram showing an example of the densities of colorants used for pixels in region 501 shown in FIG. 5A. In this example, a case will be described in which the first and second densities are maximum densities. The left side of FIG. 5B is a graph showing the densities of colorants for second pixel P2, first pixel P1, pixel P3a, and pixel P3b in region 501 before correction by the processing of step S406 shown in FIG. 4. First pixel P1, pixel P3a, and pixel P3b are part of first region R1. Second pixel P2 is part of second region R2.

[0049] The right side of FIG. 5B is a graph showing pixel values ​​corrected by the process of step S406 for the second pixel P2, the first pixel P1, the pixel P3a, and the pixel P3b. The same color material is used for the second pixel P2, the first pixel P1, the pixel P3a, and the pixel P3b. The density of the second color material used for the second pixel P2 is maximum, and the density of the color material used for the first pixel P1, the pixel P3a, and the pixel P3b is lower than the maximum density. In this case, in step S406 illustrated in FIG. 4, the correction unit 110 reduces the density of the first color material used for the first pixel P1. As a result, the image forming apparatus 100 according to this embodiment can prevent characters and lines on a colored background from appearing thicker than characters and lines on an uncolored area.

[0050] Second Embodiment The second embodiment will be described with reference to Figures 6A to 6E. Note that in the drawings, the same or equivalent elements are given the same reference numerals, and redundant explanations will be omitted.

[0051] The determination unit 109 according to this embodiment selects, as the first pixel P1, a pixel within a predetermined range from the second pixel P2, from among a plurality of pixels included in the first region R1 adjacent to the second region R2 including the second pixel P2. In this case, the correction unit 110 according to this embodiment performs a correction process to reduce the density of the first colorant so that the density of the first pixel P1 decreases as the pixel P1 is closer to the second pixel P2.

[0052] Correction of the pixel value of the first pixel P1 in the image forming apparatus 100 according to this embodiment will be described in detail with reference to FIGS. 6A and 6B.

[0053] FIG. 6A is a diagram showing an example of a region 601 including a linear object and the background of the linear object. In this example, a case will be described in which the first density and the second density are maximum densities. The region 601 includes a portion of the second region R2 representing the linear object and a portion of the first region R1 representing the colored background. The first pixel P1a, the first pixel P1b, and the pixel P3c are part of the first region R1. The second pixel P2 is part of the second region R2. In FIG. 6A, the first pixel P1 is a pixel within a range of two pixels in the second direction D2 from the second pixel P2, among the multiple pixels included in the first region R1.

[0054] FIG. 6B is a graph showing an example of the density of color materials after correction for pixels in region k shown in FIG. 6A. In this example, a case where the first density and the second density are maximum densities will be described. Specifically, FIG. 6B shows an example of the density of color materials after correction by the processing of step S406 for second pixel P2, first pixel P1a, first pixel P1b, and pixel P3c. FIG. 6C is a diagram showing an example of image IMG after correction shown in FIG. 6B.

[0055] The same colorant is used for the second pixel P2, the first pixel P1a, the first pixel P1b, and the pixel P3c. Furthermore, the density of the second colorant used for the second pixel P2 is the maximum density, while the density of the colorant used for the first pixel P1a, the first pixel P1b, and the pixel P3c is lower than the maximum density. Furthermore, the first pixel P1a is closer to the second pixel P2 than the first pixel P1b. Therefore, in step S406 illustrated in FIG. 4, the correction unit 110 reduces the density of the colorant used for the first pixel P1a to be lower than the density of the colorant used for the first pixel P1b. This reduces the density of the boundary between the colored background and the linear object.

[0056] Referring to FIGS. 6D and 6E, a comparative example of the image forming apparatus 100 according to this embodiment will be described in which the densities of the color materials used for the first pixel P1a and the first pixel P1b are made the same.

[0057] Fig. 6D is a graph showing an example of the density of color materials after correction for pixels in region 601 shown in Fig. 6A. Specifically, Fig. 6D shows a comparative example of the density of color materials after correction by the processing of step S406 shown in Fig. 4 for first pixel P1a, first pixel P1b, and pixel P3c. Fig. 6E is a diagram showing an example of image IMG after correction shown in Fig. 6D.

[0058] As illustrated in Fig. 6D, if the correction unit 110 corrects the density of the color material used for the first pixel P1a and the first pixel P1b so that they are the same, overcorrection will occur, and a whiteout will occur at the boundary between the second region R2 and the first region R1, as illustrated in Fig. 6E. On the other hand, as illustrated in Fig. 6B, the correction unit 110 reduces the density of the first color material used for the first pixel P1a and the first pixel P1b so that the density decreases as the distance from the second pixel P2 decreases. As illustrated in Fig. 6C, the image forming apparatus 100 according to this embodiment can suppress the occurrence of a whiteout at the boundary between the second region R2 and the first region R1.

[0059] As described above, the image forming apparatus 100 according to this embodiment can reduce the possibility of white spots with clear edges occurring adjacent to linear objects due to overcorrection.

[0060] (Third embodiment) The second embodiment will be described with reference to Figures 7 to 9. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant explanations will be omitted.

[0061] As a correction process, the correction unit 110 in this embodiment performs a process to reduce the concentration of the first colorant used for the first pixel P1 closest to the second pixel P2 included in the second region R2 adjacent to the rear end side of the second direction D2, for the first region R1 including the first pixel P1, when the first colorant is one color.

[0062] Furthermore, as a correction process, the correction unit 110 of this embodiment performs a process of reducing the density of the first color material so that the density of the first color material is lower for first pixels P1 that are closer to a second pixel P2 included in a second region R2 adjacent to the rear end side of a first region R1 including the first pixel P1 in the second direction D2.

[0063] 7 is a flowchart showing an example of the operation of the image forming apparatus 100 according to this embodiment. The processes of steps S701 to S705 are the same as the processes of steps S401 to S405 shown in FIG. 4, and therefore detailed description thereof will be omitted.

[0064] In step S705, if the density of the first color material used for the first pixel P1 selected in step S702 is lower than the first density, the determination unit 109 determines in step S706 whether the first color material is one color. For example, assume that the first density is the maximum density. In this case, in step S705, if the density of the first color material used for the first pixel P1 selected in step S702 is lower than the maximum density, the determination unit 109 determines in step S706 whether the first color material is one color. Specifically, the determination unit 109 determines whether the first color material has one color component. If the first color material uses one color component, the determination unit 109 determines that the first color material has one color component. On the other hand, if the first color material uses two or more color components, the determination unit 109 determines that the first color material does not have one color component.

[0065] If the first color material is one color in step S706, the correction unit 110 corrects the pixel value of the pixel closest to the second pixel P2 among the multiple pixels included in the first region R1 including the first pixel P1 in step S707. Specifically, the correction unit 110 reduces the density of the first color material used for the pixel closest to the second pixel P2 among the multiple pixels included in the first region R1 including the first pixel P1.

[0066] On the other hand, if the first color material is not one color in step S706, in step S708, the correction unit 110 corrects the first color material used for multiple pixels within a predetermined range from the second pixel P2 among the multiple pixels included in the first region R1.

[0067] In step S709, the correction unit 110 determines whether to end the process of correcting pixel values. For example, if the determination unit 109 has selected all pixels indicated by the pixel value information indicated by the image data 111 as first pixels P1 in step S702, the correction unit 110 determines to end the process of correcting pixel values. Alternatively, if the determination unit 109 has selected all pixels included in a first region adjacent in the second direction D2 to a second region indicating a linear object along the first direction D1 as first pixels P1 in step S702, the correction unit 110 may determine to end the process of correcting pixel values.

[0068] If the correction unit 110 determines not to end the pixel value correction process in step S709, the control unit 108 returns the process to step S702 and continues the process. On the other hand, if the correction unit 110 determines to end the pixel value correction process in step S709, the control unit 108 ends the pixel value correction process.

[0069] 8 shows an example of a case where a first region R1 adjacent to a second region R2 uses a single color of first colorant and the density of the colorant is reduced for multiple pixels included in the first region R1. The second region R2 shows a linear object. The first region R1 shows the colored background of the linear object shown by the second region R2.

[0070] 8, when the first colorant and the second colorant used in the second region R2 are the same and the first colorant is a single color, if the correction unit 110 reduces the density of the first colorant used for multiple first pixels within a range of two or more pixels from the second pixel P2, overcorrection occurs, resulting in a whiteout at the boundary between the first region R1 and the second region R2. As a result, the boundary between the first region R1 and the second region R2 is perceived as being excessively bright.

[0071] 9 shows an example of a case where the first colorant used in the first region R1 is not a single color, and the density of the colorant is reduced for multiple pixels included in the first region R1. The second region R2 shows a linear object. The first region R1 shows the colored background of the linear object shown in the second region R2.

[0072] As illustrated in Figure 9, when the first colorant and the second colorant used in the second region R2 are the same and the first colorant is not a single color, even if the correction unit 110 reduces the concentration of the first colorant used for multiple first pixels P1 within a range of two or more pixels from the second pixel P2 included in the second region R2, the boundary between the first region R1 and the second region R2 can be prevented from being overly perceived.

[0073] As described above, when a linear object is printed on a colored background, the image forming apparatus 100 according to this embodiment changes the range of pixel regions for which density is suppressed depending on whether the background color is a single color or a mixed color. As a result, the image forming apparatus 100 according to this embodiment can effectively suppress the density of the boundary between the colored background and the linear object while suppressing whiteout caused by overcorrection at the boundary between the colored background and the linear object.

[0074] (Fourth embodiment) A fourth embodiment will be described with reference to FIGS.

[0075] The correction unit 110 according to this embodiment performs a process of reducing the density of the first color material by filtering as a correction process.

[0076] The correction unit 110 according to the present embodiment performs a correction process by filtering to reduce the density of the first colorant used for the first pixel P1 included in the first region R1 when a portion of the first object represented by the first region R1 overlaps with a portion of the second object represented by the second region R2, the second object using a colorant with a density equal to or greater than a second density, or when a single color is used in the region bordering the boundary between the first region R1 and the second region R2. For example, assume that the first density and the second density are maximum densities. In this case, the correction unit 110 according to the present embodiment performs a correction process by filtering to reduce the density of the first colorant used for the first pixel P1 included in the first region R1 when a portion of the first object represented by the first region R1 overlaps with a portion of the second object represented by the second region R2, the second object using a colorant with a density equal to or greater than a second density, or when a single color is used in the region bordering the boundary between the first region R1 and the second region R2.

[0077] Alternatively, the correction unit 110 according to this embodiment may perform a correction process to reduce the concentration of the color material used for the pixel furthest to the tip in the second direction D2 among the multiple pixels included in the second region R2 including the second pixel P2.

[0078] Furthermore, the correction unit 110 according to this embodiment may perform an expansion / contraction process on the second region R2 including the second pixel P2 as a correction process, and may execute a process to reduce the concentration of the color material used for the pixel furthest to the end of the second pixel P2 in the second direction D2 among the multiple pixels included in the expanded / contracted second region R2.

[0079] In this embodiment, when the area adjacent to the boundary between the first region R1 and the second region R2 does not use a single color of colorant and the density of the colorant used in the area adjacent to the boundary between the first region R1 and the second region R2 is equal to or greater than a second density, the correction unit 110 performs an expansion / contraction process on the second region R2 to reduce the density of the colorant used for the pixel furthest to the front in the second direction D2 among the multiple pixels included in the second region R2, thereby blanking the pixel. For example, it is assumed that the first density and the second density are maximum densities. In this case, as a correction process, the correction unit 110 of this embodiment performs an expansion / contraction process on the second region R2 if the color material used in the region adjacent to the boundary between the first region R1 and the second region R2 is not a single color and the density of the color material used in the region adjacent to the boundary between the first region R1 and the second region R2 is the maximum density, and reduces the density of the color material used for the pixel furthest to the end in the second direction D2 among the multiple pixels included in the second region R2, thereby blanking out that pixel.

[0080] Furthermore, the correction unit 110 according to the present embodiment may perform, as the correction process, a process of reducing the density of the colorant used in the second region R2 including the second pixel P2, and moving the second region R2 in which the second colorant is used a predetermined number of pixels toward the rear end in the second direction D2 and superimposing the duplicated second region R2. In other words, the correction unit 110 according to the present embodiment may perform, as the correction process, a process of reducing the density of the colorant used in the second region R2 including the second pixel P2, and duplicating the second region R2 before reducing the density of the colorant, and moving the duplicated second region R2 a predetermined number of pixels toward the rear end in the second direction D2 and superimposing the duplicated second region R2.

[0081] In this embodiment, when the colorant density used in the region adjacent to the boundary between the first region R1 and the second region R2 is not a single color and the density of the colorant used in the region adjacent to the boundary between the first region R1 and the second region R2 is equal to or greater than a second density, the correction unit 110 performs a correction process in which the density of the colorant used in the second region R2 including the second pixel P2 is reduced, the second region R2 before the reduction in the colorant density is duplicated, and the duplicated second region R2 is shifted a predetermined number of pixels toward the rear end in the second direction D2 and superimposed. For example, it is assumed that the first density and the second density are maximum densities. In this case, if the colorant used in the region adjacent to the boundary between the first region R1 and the second region R2 is not a single color and the density of the colorant used in the region adjacent to the boundary between the first region R1 and the second region R2 is maximum, the correction unit 110 according to this embodiment performs a correction process in which the density of the colorant used in the second region R2 including the second pixel P2 is reduced, the second region R2 before the reduction in the colorant density is duplicated, and the duplicated second region R2 is moved a predetermined number of pixels toward the rear end in the second direction D2 and superimposed. As a result, the correction unit 110 according to this embodiment generates a low-density region of a predetermined number of pixels toward the front end in the second direction D2 in the second region R2.

[0082] FIG. 10 is a flowchart showing an example of the operation of the image forming apparatus 100 according to this embodiment.

[0083] In step S1001, the image acquisition unit 104 acquires the image data 111.

[0084] In step S1002, the determination unit 109 determines whether a portion of a first object represented by a first region R1 in an image based on the acquired image data 111 overlaps with a portion of a second object represented by a second region R2, the second object using a colorant with a density equal to or greater than a second density. For example, the first density and the second density are assumed to be maximum densities. In this case, in step S1002, the determination unit 109 determines whether a portion of the first object represented by a first region R1 in an image based on the acquired image data 111 overlaps with a portion of a second object used by a second region R2, the second object using a colorant with a density equal to or greater than a second density. The second object represents a text object or a linear object.

[0085] If a portion of the first object does not overlap a portion of the second object in step S1002, control unit 108 ends the process. On the other hand, if a portion of the first object overlaps a portion of the second object in step S1002, control unit 108 determines in step S1003 whether or not there is a third region R3 between the first object and the second object, which is a boundary region in which a color material different from that of either the first object or the second object is used. That is, determination unit 109 determines whether or not there is a third region R3 that contacts the boundary between first region R1 and second region R2.

[0086] If it is determined in step S1003 that the third region R3 does not exist between the first object and the second object, the control unit 108 proceeds to step S1005.

[0087] On the other hand, if it is determined in step S1003 that the third region R3 exists between the first object and the second object, the control unit 108 proceeds to step S1004.

[0088] In step S1004, the determination unit 109 determines whether a colorant containing multiple color components is used in the third region R3. If in step S1004 a colorant containing multiple color components is not used in the third region R3, the control unit 108 proceeds to step S1005. On the other hand, if in step S1004 more than one color is used for the third region R3, the control unit 108 proceeds to step S1006.

[0089] In step S1005, correction unit 110 performs filtering to correct the density of the first colorant used for first pixel P1 included in first region R1 representing the first object. As a result, correction unit 110 can make objects on a colored background sharper and smoother through the processing of step S1005, while preventing objects on a colored background from appearing thicker than objects in an uncolored region.

[0090] In step S1006, the determination unit 109 determines whether or not there is a text object or a line object on a background using the same color material.

[0091] If, in step S1006, it is determined that there is no text object or linear object on the background using the same color material, then in step S1007, the correction unit 110 reduces the density of the first color material used for the first pixel P1 included in the first region R1 representing the first object by filtering. Alternatively, if, in step S1006, there is no text object or linear object on the background using the same color material, then in step S1007, the correction unit 110 performs an expansion / contraction process on the second region R2, and, among the multiple pixels included in the expanded / contracted second region R2, reduces the density of the color material used for the pixel closest to the second pixel P2 in the second direction D2, thereby blanking that pixel. This allows the correction unit 110 to adjust the thickness of the text object or linear object represented by the second region R2. As a result, by processing step S1007, correction unit 110 can adjust the thickness of character objects or linear objects on a colored background, while suppressing the phenomenon in which character objects or linear objects on a colored background appear thicker than objects on uncolored areas.

[0092] On the other hand, if a text object or a linear object is present on a background using the same color material in step S1006, in step S1008, the correction unit 110 reduces the density of the color material used in the second region R2 including the second pixel P2, and moves the second region R2 using the second color material a predetermined number of pixels toward the rear end in the second direction D2 to superimpose it. This allows the correction unit 110 to generate a low-density region of a predetermined number of pixels toward the front end in the second direction D2 in the second region R2. By performing the processing in step S1008, the correction unit 110 shifts and positions the object without performing filtering or expansion / contraction processing for each pixel, thereby reducing the memory and processing time required for filtering or expansion / contraction processing.

[0093] When printing image data having multiple pages, the printing direction relative to the orientation of the image data (up, down, left, right) may change for each page when performing double-sided printing or when performing aggregate printing in which multiple pages are allocated to one page. In this way, when the printing direction relative to the orientation of the image data changes for each page, the correction unit 110 may rotate the image so that the printing direction is a fixed, predetermined direction, perform filtering or expansion / reduction processing, and then reversely rotate the image to return it to the original image data orientation, or may switch between multiple parameters obtained by rotating the parameters of the filtering or expansion / reduction processing by 90 degrees, 180 degrees, or 270 degrees depending on the printing direction.

[0094] FIG. 11 is a diagram showing an example of the process of step S1008 illustrated in FIG.

[0095] In the first region R1, a character object, "A," represented by the second region R2, is displayed on a background region represented by the second region R1. Furthermore, the color materials used in the first region R1 and the second region R2 are the same. In this case, the correction unit 110 shifts the character object represented by the second region R2 a predetermined number of pixels toward the rear end in the second direction D2 and superimposes it. As a result, as shown in the lower part of FIG. 11 , a low-density region of a predetermined number of pixels can be generated toward the front end in the second direction D2 in the second region R2. This allows the image forming apparatus 100 according to this embodiment to suppress the phenomenon in which a character object or a linear object on a colored background appears thicker than an object on an uncolored region.

[0096] Fifth Embodiment A fifth embodiment will be described.

[0097] When uncolored areas and colored areas are alternately arranged in the first direction D1, if a linear object is arranged that intersects the uncolored areas and colored areas and the color material used in the colored areas is the same as the color material used in the areas representing the linear object, the linear object on the colored background is likely to appear thicker than the linear object on the uncolored area. Note that the uncolored area is an area where the image forming unit 105 does not apply color material to the paper 201.

[0098] Therefore, the correction unit 110 according to the present embodiment performs a correction process to reduce the density of the first color material when uncolored regions and first regions R1 composed of first pixels P1 are alternately arranged in the first direction D1. As a result, the image forming apparatus 100 according to the present embodiment can reduce the density of the color material when a phenomenon in which a linear object on a colored background appears thicker than an object in an uncolored region is easily perceived, thereby suppressing the adverse effects of reducing the density of the color material.

[0099] (Sixth embodiment) A sixth embodiment will be described.

[0100] The correction unit 110 according to this embodiment reduces the density of the first colorant used for the first pixel P1 when the density of the second colorant used for the second pixel P2 within a predetermined range of pixels on the rear end side of the first pixel P1 in the second direction D2 is equal to or greater than the second density. For example, assume that the first density and the second density are maximum densities. In this case, the correction unit 110 according to this embodiment reduces the density of the first colorant used for the first pixel P1 when the density of the second colorant used for the second pixel P2 within a predetermined range of pixels on the rear end side of the first pixel P1 in the second direction D2 is maximum.

[0101] For example, if a linear object is placed on a colored background and the linear object is sufficiently thin, the phenomenon of the linear object appearing thicker on the colored background than on an uncolored area is unlikely to occur. Here, what is considered sufficiently thin varies depending on the image forming apparatus 100. Therefore, if the linear object is sufficiently thin, the correction unit 110 does not correct the density of the color material used for pixels of the colored background adjacent to the linear object. Specifically, in this embodiment, the correction unit 110 performs correction processing when the determination unit 109 determines that the first and second color materials are the same, the first color material has a density lower than the first density, and the second color material has a density equal to or greater than the second density, and multiple second pixels P2 using the second color material are consecutively located at least one pixel behind the first pixel P1 in the second direction D2. For example, the first density and the second density are maximum densities. In this case, the correction unit 110 according to the present embodiment executes correction processing when the determination unit 109 determines that the first and second color materials are the same, the first color material is not at its maximum density, but the second color material is at its maximum density, and multiple second pixels P2 using the second color material are consecutively located at least the first number of pixels behind the first pixel P1 in the second direction D2. This allows the image forming apparatus 100 according to the present embodiment to prevent adverse effects caused by reducing the density of the color material in thin line regions.

[0102] Furthermore, for example, if a linear object is placed on a colored background and the linear object is sufficiently thick, the phenomenon of the linear object appearing thicker on the colored background than on an uncolored area is less noticeable. Therefore, when the linear object is sufficiently thick, the correction unit 110 does not correct the density of the color material used for pixels of the colored background adjacent to the linear object. Specifically, in this embodiment, the correction unit 110 performs correction processing when the determination unit 109 determines that the first and second color materials are the same, the first color material has a density lower than the first density, and the second color material has a density equal to or greater than the second density, and multiple second pixels P2 using the second color material are consecutively located at the rear end of the first pixel P1 in the second direction D2, up to a second number of pixels greater than the first number of pixels. For example, when the resolution is 600 dpi and the second number of pixels is 22, the correction unit 110 performs correction processing for an area with a width of 1 mm or less. For example, the first density and the second density are assumed to be maximum densities. In this case, the correction unit 110 according to the present embodiment executes correction processing when the determination unit 109 determines that the first colorant and the second colorant are the same, the first colorant is not at its maximum density, but the second colorant is at its maximum density, and multiple second pixels P2 using the second colorant are consecutively located at a second number of pixels greater than the first number of pixels and toward the rear end in the second direction D2 from the first pixel P1. This allows the image forming apparatus 100 according to the present embodiment to prevent adverse effects caused by reducing the density of the colorant in the thick line region.

[0103] Seventh Embodiment A seventh embodiment will be described.

[0104] In the image forming apparatus 100 according to this embodiment, when it is determined that the first color material and the second color material are the same, and the first mask area adjacent to the first pixel P1 and at the front end in the second direction D2 is composed of pixels with a density lower than the first density, and the second mask area adjacent to the first pixel P1 and at the rear end in the second direction D2 is composed of pixels with a density higher than the second density, the correction unit 110 according to this embodiment performs a correction process on the first pixel P1.

[0105] For example, if the average pixel value of the pixels included in the first mask region is lower than a first density and the average pixel value of the pixels included in the second mask region is higher than a second density, the correction unit 110 may perform the correction process on the first pixel P1. Alternatively, if the most frequent pixel value of the pixels included in the first mask region is lower than a first density and the most frequent pixel value of the pixels included in the second mask region is higher than a second density, the correction unit 110 may perform the correction process on the first pixel P1. This allows the correction unit 110 to perform the correction process on the first pixel P1 even if the pixel values ​​of the pixels surrounding the first pixel P1 are not uniform. As a result, even if the color of the colored background is not uniform, it is possible to prevent the phenomenon in which characters and lines on a colored background appear thicker than characters and lines on an uncolored region.

[0106] Furthermore, the correction unit 110 according to the present embodiment may scan a mask composed of the first mask region and the second mask region in the second direction D2 and determine whether or not to perform correction processing on the first pixel P1. Specifically, if it is determined that the first color material and the second color material are the same, and the mask composed of the first mask region and the second mask region is scanned in the second direction D2, and the region surrounding the first pixel P1 matches the mask, the correction unit 110 according to the present embodiment performs correction processing.

[0107] As described above, the image forming apparatus 100 according to this embodiment can suppress the phenomenon in which characters and lines on a colored background appear thicker than characters and lines on an uncolored area, even if the pixels that make up the characters and lines on the colored background are not aligned in the first direction D1.

[0108] An eighth embodiment will now be described.

[0109] The correction unit 110 according to this embodiment performs a correction process to reduce the density of the first color material to make the first pixel P1 white. Therefore, the correction unit 110 does not need to determine the density of the first color material after the correction process depending on the density of the first color material before the correction process, and the processing load can be reduced.

[0110] When the correction unit 110 sets the density of the first pixel P1 to white, a blank space appears next to the second pixel P2. However, when the image forming unit 105 applies a second colorant to the paper 201 for the second pixel P2, the width of the blank space becomes thinner due to the physical dot gain phenomenon. Furthermore, light diffused and scattered not only on the surface of the paper 201 but also within the paper 201 forms the white portion of the paper 201. However, due to the optical dot gain phenomenon, which reduces the optical density of the area surrounding the colorant-applied area because light obliquely incident on the paper 201 is blocked by the area to which the colorant is applied and / or is spectrally partially transmitted through the area to which the colorant is applied, the position of the first pixel P1 that is set white is less likely to be perceived as a white dot or white on the paper 201. Furthermore, by providing the blank area, the influence of the second pixel P2, which has a predetermined second density or higher, can be eliminated. Specifically, the provision of the blank area significantly reduces the potential diffusion effect on the photosensitive member from the second pixel P2 during image formation, as well as the electrostatic and electrifying effects during transfer to the photosensitive member and transfer belt 122. As described above, the image forming apparatus 100 according to this embodiment can reduce the processing load while suppressing the phenomenon in which characters and lines on a colored background appear thicker than characters and lines on an uncolored area.

[0111] The processes executed in the above embodiments are not limited to the processing modes exemplified in the embodiments. The above-described functional blocks may be realized using either a logic circuit (hardware) formed in an integrated circuit or the like, or software using a CPU.

[0112] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that achieves the same effect, or a configuration that can achieve the same purpose. The present disclosure also includes within its technical scope embodiments obtained by appropriately combining the technical means disclosed in different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of symbols]

[0113] 100 image forming apparatus, 101 storage unit, 102 operation unit, 103 display unit, 104 image acquisition unit, 105 image forming unit, 106 paper transport unit, 107 image output unit, 108 control unit, 109 determination unit, 110 correction unit, 111 image data, 121 photosensitive drum, 122 transfer belt, 201 paper, 501 area, 601 area, D1 first direction, D2 second direction, IMG image, P1 first pixel, P1a first pixel, P1b first pixel, P2 second pixel, P3a pixel, P3b pixel, P3c pixel, R1 first area, R2 second area, R3 third area

Claims

1. an image forming unit that deposits color material onto a sheet for each of a plurality of pixels aligned in a first direction; a paper transport unit that transports the paper in a second direction; An image forming apparatus comprising: a determination unit that determines whether a first color material used for a first pixel among the plurality of pixels is the same as a second color material used for a second pixel that is located on a rear end side of the first pixel in the second direction and adjacent to the first pixel; a correction unit that executes a correction process to correct the density of the first colorant when it is determined that the first colorant and the second colorant are the same, the density of the first colorant is lower than a first density, and the density of the second colorant is equal to or higher than a second density that is equal to or higher than the first density; Equipped with Image forming device.

2. The correction unit executes the correction process when it is determined that the first color material and the second color material are the same, the density of the first color material is not the maximum density, and the density of the second color material is the maximum density. The image forming apparatus according to claim 1 .

3. The difference between the first concentration and the second concentration is greater than a predetermined concentration difference. The image forming apparatus according to claim 1 .

4. When a plurality of second pixels are arranged in the first direction, a plurality of first pixels are arranged along the plurality of second pixels. The image forming apparatus according to claim 1 .

5. The correction process is to reduce the density of the first color material. The image forming apparatus according to claim 1 .

6. the first pixel is a pixel within a predetermined range from the second pixel among a plurality of pixels included in a first region adjacent to a second region including the second pixel in the second direction, The correction process reduces the density of the first color material so that the density of the first pixel is lower as the distance from the second pixel is closer to the first pixel. The image forming apparatus according to claim 1 .

7. When the first color material is one color, the correction process reduces a density of the first color material used for a first pixel closest to a second pixel included in a second region adjacent to a rear end side of a first region including the first pixel in the second direction, and When the first color material is not one color, the correction process reduces the density of the first color material so that the density of the first color material decreases as the distance from the second pixel included in a second region adjacent to the first region including the first pixel on the rear end side in the second direction decreases. The image forming apparatus according to claim 1 .

8. The correction process is to reduce the density of the first color material by filtering. The image forming apparatus according to claim 1 .

9. The correction process is to perform an expansion / contraction process on a second region including the second pixel, and to reduce the density of a color material used for a pixel that is furthest to the tip side in the second direction relative to the second pixel among a plurality of pixels included in the expanded / contracted second region. The image forming apparatus according to claim 1 .

10. The correction process reduces the density of the color material used in the second region including the second pixel, and moves the second region in which the second color material is used by a predetermined number of pixels toward the rear end in the second direction to superimpose the second region. The image forming apparatus according to claim 1 .

11. When uncolored regions and first regions formed of the first pixels are alternately arranged in the first direction, the correction process reduces the concentration of the first color material used for the first pixels forming the first regions. The image forming apparatus according to claim 1 .

12. The correction unit performs the correction process when it is determined that the first color material and the second color material are the same, the density of the first color material is lower than the first density, and the density of the second color material is equal to or higher than the second density, and when a plurality of second pixels are consecutive on the rear end side in the second direction by a distance equal to or greater than the first pixel number from the first pixel. The image forming apparatus according to claim 1 .

13. The correction unit performs the correction process when it is determined that the first color material and the second color material are the same, the density of the first color material is lower than the first density, and the density of the second color material is equal to or higher than the second density, and when a plurality of second pixels are consecutive from the first pixel on a rear end side in the second direction, the number of second pixels being equal to or less than a second number of pixels that is greater than the first number of pixels. The image forming apparatus according to claim 12.

14. When it is determined that the first color material and the second color material are the same, a first mask area adjacent to the first pixel and on the leading end side in the second direction is made up of pixels with a density lower than the first density, and a second mask area adjacent to the first pixel and on the trailing end side in the second direction is made up of pixels with a density higher than the second density, the correction unit executes the correction process. The image forming apparatus according to claim 1 .

15. If it is determined that the first color material and the second color material are the same, and a mask configured with the first mask area and the second mask area is scanned in the second direction, and if an area surrounding the first pixel matches the mask, the correction unit executes the correction process. The image forming apparatus according to claim 14.

16. The correction process is to reduce the density of the first colorant to make the first pixel white. The image forming apparatus according to claim 1 .

17. determining whether a first color material used for a first pixel among a plurality of pixels aligned in a first direction is the same as a second color material used for a second pixel located on the rear end side of the first pixel in a second direction; a step of executing a correction process to correct the density of the first colorant when it is determined that the first colorant and the second colorant are the same, the density of the first colorant is lower than a first density, and the density of the second colorant is equal to or higher than a second density that is equal to or higher than the first density; a step of depositing coloring material onto a sheet for each of a plurality of pixels aligned in the first direction; conveying the paper in the second direction; An image forming method comprising:

18. an image forming unit that deposits color material onto a sheet for each of a plurality of pixels aligned in a first direction; a paper transport unit that transports the paper in a second direction; A computer that controls an image forming apparatus including: a function of determining whether a first color material used for a first pixel among the plurality of pixels is the same as a second color material used for a second pixel located on the rear end side of the first pixel in the second direction; a function of executing a correction process to correct the density of the first colorant when it is determined that the first colorant and the second colorant are the same, the density of the first colorant is lower than a first density, and the density of the second colorant is equal to or higher than a second density that is equal to or higher than the first density; A program that executes the following.

Images