Image forming apparatus and image processing program

Abstract

To enable a color representation approximating a white image, when forming an image on a colored recording medium, without requiring a white toner, but by using only ordinary color toners for color image formation and a mechanism for image formation with the respective color toners.SOLUTION: An image forming apparatus 1 includes: a white region extractor 101 that extracts a white region for each of segmented regions from an output target image; a high-brightness region extractor 102 that extracts a high-brightness region consisting of a high-brightness image from the segmented regions adjacent to the white region; a color change determiner 103 that determines whether a change in the pixel value of the image inside of the high-brightness region is a change from lower to higher brightness; a region generator 104 that, upon determination that the image of the high-brightness region is a change from lower to higher brightness, copies a portion of a region on a higher-brightness side of the high-brightness region and generates an adjustment white region; and an image regenerator 105 that replaces the white region with the adjustment white region to regenerate the output target image.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and an image processing program, and more particularly to a technique for expressing a white area formed by a white image without using white toner. [Background technology]

[0002] Image forming devices have been proposed that form white images using white toner. For example, as disclosed in Patent Document 1 below, an image forming device has been proposed in which, when forming an image on a colored recording medium using white toner, a base toner layer is inserted between the white toner layer and the colored recording medium, and the toner layer formed by overlapping the base toner layer and the white toner layer is fixed onto the recording medium. In this way, the image forming device disclosed in Patent Document 1 below prevents the white toner from seeping into the recording medium due to fixing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-173377 Summary of the Invention [Problem to be solved by the invention]

[0004] However, forming a white image using the above image forming apparatus requires white toner and a mechanism for forming an image using the white toner, and therefore, an image cannot be formed using white toner using a general image forming apparatus for forming color images that does not have a mechanism for forming an image using the white toner.

[0005] The present invention has been made in consideration of the above circumstances, and aims to enable color representation that approximates a white image when forming an image on a colored recording medium, without requiring white toner, using only the color toners for general color image formation and a mechanism for forming an image using those color toners. [Means for solving the problem]

[0006] An image forming apparatus according to one aspect of the present invention includes an image forming unit that forms an image on a recording medium, a white area extraction unit that extracts a white area made up of a white image for each predetermined divided area from an image to be output, a high brightness area extraction unit that extracts a high brightness area made up of an image with a higher brightness from divided areas adjacent to the white area extracted by the white area extraction unit from the image to be output, and a high brightness area extraction unit that extracts a high brightness area made up of an image with a higher brightness from among divided areas adjacent to the white area extracted by the high brightness area extraction unit, and a high brightness area extraction unit that extracts a high brightness area from the image to be output, the high brightness area extraction unit extracting a high brightness area from among divided areas adjacent to the white area extracted by the high brightness area extraction unit ... a color change determination unit that determines whether the image in the high-brightness region has changed from high brightness to low brightness; an area generation unit that, when the color change determination unit determines that the image in the high-brightness region has changed from high brightness to low brightness, copies a portion of the high-brightness side of the high-brightness region and generates an adjustment white area of ​​a size that matches the size of the white area; an image regeneration unit that replaces the white area with the adjustment white area generated by the area generation unit to regenerate the image to be output; and a control unit that causes the image to be output regenerated by the image regeneration unit to be formed on a recording medium by the image formation unit.

[0007] An image forming program according to one aspect of the present invention includes a white area extraction unit that extracts a white area composed of a white image from an image to be output for each predetermined divided area; a high-brightness area extraction unit that extracts a high-brightness area composed of an image with higher brightness from divided areas adjacent to the white area extracted by the white area extraction unit for each divided area from the image to be output; and a high-brightness area extraction unit that extracts a high-brightness area composed of an image with higher brightness from divided areas adjacent to the white area extracted by the high-brightness area extraction unit, the high-brightness area extracting unit extracting a high-brightness area from the image to be output for each divided area. a color change determination unit that determines whether the image of the high-luminance region has changed from high luminance to low luminance; an area generation unit that, when the color change determination unit determines that the image of the high-luminance region has changed from high luminance to low luminance, copies a part of the high-luminance side of the high-luminance region and generates an adjustment white area of ​​a size that matches the size of the white region; an image regeneration unit that replaces the white region with the adjustment white area generated by the area generation unit to regenerate the image to be output; and a control unit that causes the image formation unit to form the image to be output regenerated by the image regeneration unit on a recording medium. [Effects of the Invention]

[0008] According to the present invention, when forming an image on a colored recording medium, no white toner is required, and color representation approximating a white image is possible using only the color toners for general color image formation and the image formation mechanism using those color toners. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing an internal configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 3] 10 is a flowchart showing a first embodiment of white representation processing performed on an image to be output. [Figure 4] 10A and 10B are diagrams illustrating an example of an output target image and divided areas. [Figure 5] FIG. 10 is a diagram illustrating an example of a portion of an image to be output having a high-brightness area and a white area. [Figure 6] FIG. 10 is a diagram illustrating an example of a portion of an image to be output having a high-brightness area and a white area. [Figure 7] 10A to 10C are diagrams illustrating a process of generating a white adjustment region. [Figure 8] 10A and 10B are diagrams illustrating a process of replacing the white area with an adjustment white area and regenerating an image that constitutes each divided area. [Figure 9] 10A and 10B are diagrams illustrating a process of generating a white area for inversion adjustment. [Figure 10] 10A to 10C are diagrams illustrating a process for generating a white correction region. [Figure 11] 10A and 10B are diagrams illustrating a process of regenerating an image to be output using a white area for inversion adjustment and a white area for correction. [Figure 12] This is a diagram illustrating the visibility of the Craik-O'Brien-Cornsweet illusion. [Figure 13] FIG. 10 is a block diagram showing the internal configuration of an image forming apparatus used to execute white representation processing according to a second embodiment. [Figure 14] 10 is a flowchart showing a second embodiment of white representation processing performed on an image to be output. [Figure 15] 10A, 10B, and 10C are diagrams showing pixel values ​​of each pixel for the magenta color component of the CMYK values ​​when the background color of the recording paper is magenta. [Figure 16] FIG. 1A is a diagram showing an example of an image to be output before white representation processing, and FIG. 1B is a diagram showing an example of an image to be output after white representation processing. DETAILED DESCRIPTION OF THE INVENTION

[0010] An image forming apparatus and an image processing program according to the present invention will be described below with reference to the drawings. Fig. 1 is a cross-sectional view showing an image forming apparatus according to one embodiment of the present invention.

[0011] 1, the image forming apparatus 1 is an MFP (multi-function peripheral) that has multiple functions such as a copy function and a scanner function. The image forming apparatus 1 includes an image reading unit 11 and an image forming unit 12.

[0012] The image reading unit 11 has an image pickup element (CCD sensor, contact image sensor, etc.) that optically reads an image of a document, and image data representing the image of the document is generated from the analog output of this image pickup element.

[0013] The image forming unit 12 forms an image represented by the image data on recording paper by an inkjet method, and has line heads (an example of ink heads) 55 that eject ink droplets of four colors (black, cyan, magenta, and yellow). Each line head 55 ejects ink droplets of the corresponding color onto recording paper P that has been transported from the paper feed device 14 to the transport unit 54 via the transport path 53, thereby forming a color image on the recording paper P.

[0014] The transport unit 54 includes a drive roller 68, a driven roller 69, a tension roller 65, and a transport belt 66. The transport belt 66 is an endless belt that is stretched over the drive roller 68, the driven roller 69, and the tension roller 65. The drive roller 68 is a roller that is driven to rotate clockwise by a motor (not shown), and as the drive roller 68 is driven to rotate, the transport belt 66 moves in a clockwise direction, and the driven roller 69 and the tension roller 65 are also driven to rotate clockwise.

[0015] The tension roller 65 is a roller for maintaining an appropriate tension on the conveyor belt 66. The attraction roller 67 is in contact with the conveyor belt 66 and charges the conveyor belt 66, thereby electrostatically attracting the recording paper P fed from the paper feeder 14 to the conveyor belt 66.

[0016] The recording paper P on which the image of the original has been formed by the image forming unit 12 passes through a relay transport path and is discharged onto a discharge tray 63 via a discharge roller 61 .

[0017] The paper feed device 14 is equipped with a first paper feed cassette 71, a second paper feed cassette 72, and a manual feed tray 9, and recording paper P is transported and supplied from either of the paper feed cassettes 71, 72 to the conveying path 53, or recording paper P is transported and supplied from the manual feed tray 9 to the image forming unit 12.

[0018] Fig. 2 is a block diagram showing the internal configuration of the image forming apparatus 1. As shown in Fig. 2, the image forming apparatus 1 includes an image reading unit 11, an image forming unit 12, an operation unit 21, a display unit 22, a touch panel 24, a storage unit 26, paper feed cassettes 71 and 72, and a control unit 10. These components are capable of transmitting and receiving data or signals to and from each other via a bus.

[0019] The operation unit 21 includes physical keys such as a numeric keypad, a decision key, a start key, etc. The display unit 22 is configured with a liquid crystal display (LCD: Liquid Crystal Display), an organic light-emitting diode (OLED: Organic Light-Emitting Diode) display, or the like.

[0020] A touch panel 24 is disposed on the screen of the display unit 22. The touch panel 24 is a so-called resistive or capacitive touch panel, which detects contact (touch) of a user's finger or the like with the touch panel 24 along with the contact position, and outputs a detection signal indicating the coordinates of the contact position to a control unit 100 (described later) of the control unit 28. The touch panel 24 is considered to be a part of the operation unit 21.

[0021] The storage unit 26 is a large-capacity storage device such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive), and stores various application programs and various data.

[0022] The communication unit 15 is composed of a communication module and the like, and transmits and receives various data to and from external devices via a network.

[0023] The control unit 10 is composed of a processor, a random access memory (RAM), a read-only memory (ROM), and the like. The processor may be, for example, a central processing unit (CPU), an ASIC, or a microprocessing unit (MPU). The control unit 10 functions as a control unit 100 when an operation control program stored in the ROM or the storage unit 26 is executed by the processor. The control unit 10 also functions as a white region extraction unit 101, a high-brightness region extraction unit 102, a color change determination unit 103, a region generation unit 104, and an image regeneration unit 105 when an image processing program stored in the ROM or the storage unit 26 is executed by the processor. By executing the image processing program in the processor, the control unit 10, as the control unit 100, performs functions necessary for white representation processing (described below) and image formation processing of the output target image obtained thereby.

[0024] The control unit 100 comprehensively controls the image forming apparatus 1. The control unit 100 is connected to the image reading unit 11, the image forming unit 12, the operation unit 21, the display unit 22, the touch panel 24, the storage unit 26, the communication unit 15, and each of the paper feed cassettes 71 and 72, and controls the operation of these components and transmits and receives signals or data to and from each of the components.

[0025] The control unit 100 serves as a processing unit that executes various processes required for image formation by the image forming apparatus 1. The control unit 100 also accepts operation instructions input by the user based on detection signals output from the touch panel 24 or operation of the physical keys of the operation unit 21. For example, the control unit 100 accepts touch operations on a GUI (Graphical User Interface) displayed on the screen of the display unit 22 through the touch panel 24. Furthermore, the control unit 100 has a function of controlling the display operation of the display unit 22.

[0026] The control unit 100 also controls the drive sources (motors, etc.) that operate the paper feed cassettes 71 and 72, and causes the recording paper P to be transported and supplied to the transport path 53 from either of the paper feed cassettes 71 and 72.

[0027] In the image forming apparatus 1 having such a configuration, the control unit 100 performs an image forming operation in which the image of the original is read by the image reading unit 11, recording paper is supplied from either one of the paper feed cassettes 71, 72 of the paper feed device 14 or the manual feed tray 9, and image data representing the image of the original is formed on the recording paper by the image forming unit 12.

[0028] As described above, the control unit 100 causes the image forming unit 12 to form an image represented by the image data generated by the image reading unit 11. When the control unit 100 causes the image forming unit 12 to form an image on colored recording paper, the control unit 100 causes the image forming unit 12 to form an image based on image data that has undergone white representation processing, which is image processing that can represent a white image by image formation using four colors (black, cyan, magenta, and yellow) of ink. This white representation processing is performed by the white area extraction unit 101, the high-brightness area extraction unit 102, the color change determination unit 103, the area generation unit 104, and the image regeneration unit 105. The white representation processing performed by each of these units will be described below. First, the processing for white representation processing performed by each unit will be described.

[0029] The white region extraction unit 101 extracts a white region made up of a white image for each predetermined divided region from the image to be output.

[0030] The high-brightness region extraction unit 102 extracts, for each divided region from the image to be output, a high-brightness region that is composed of an image with higher brightness from among divided regions adjacent to the white region extracted by the white region extraction unit 101.

[0031] The color change determination unit 103 determines whether the change in pixel values ​​of the image within the high-brightness area extracted by the high-brightness area extraction unit 102 is a change from low brightness to high brightness, or a change from high brightness to low brightness, toward the adjacent white area.

[0032] When the color change determination unit 103 determines that the image in the high-luminance region has changed from high luminance to low luminance, the region generation unit 104 copies a part of the region on the high-luminance side in the high-luminance region and generates an adjustment white region whose size matches the size of the white region.

[0033] The image regeneration unit 105 replaces the white area with the adjustment white area generated by the area generation unit 104, and regenerates the image to be output.

[0034] The control unit 100 causes the image forming unit 12 to form the output target image regenerated by the image regenerating unit 105 onto a recording sheet.

[0035] Furthermore, when color change determination unit 103 determines that the image in a high-luminance region has changed from low to high luminance, region generation unit 104 copies a portion of the high-luminance side of the high-luminance region to generate an adjustment white region whose size matches the size of the white region, generates an inverted adjustment white region by inverting the high-luminance and low-luminance sides of the adjustment white region, and further copies a portion of the low-luminance side of the inverted adjustment white region to generate a correction white region. In this case, image regeneration unit 105 replaces the inverted adjustment white region with the high-luminance region and replaces the correction white region with a portion of the high-luminance region adjacent to the white region, and regenerates the image to be output.

[0036] Next, a first embodiment of white representation processing performed on an image to be output will be described with reference to Fig. 3, which is a flowchart showing the first embodiment of white representation processing performed on an image to be output.

[0037] When white representation processing is performed, the white region extraction unit 101 extracts the white region from the image reading unit 1. 1 The image data generated by the image forming apparatus 10 or image data (print target data) received from an external computer or the like via the communication unit 15 is acquired as an image to be output (S1).

[0038] Next, the white region extraction unit 101 divides the image to be output into predetermined divided regions (S2).

[0039] In S2, the white region extraction unit 101 first divides the image to be output into predetermined divided regions. For example, as shown in the example of Figure 4, if the image to be output is composed of 960 pixels (px) in the x direction and 960 pixels in the y direction, a predetermined divided region is a divided region consisting of 40px in the x direction by 40px in the y direction. However, the size of the divided region is not limited to this, and can be changed individually in the x direction and the y direction.

[0040] Next, the white region extraction unit 101 determines for each divided region whether it is a white region composed of a white image (S3). A white region is a divided region in which all pixels within the region are composed of pixel values ​​indicating white, or a divided region in which a predetermined percentage (e.g., 95%) of all pixels within the region are composed of pixel values ​​indicating white. The white region extraction unit 101 determines whether all divided regions included in the image to be output are white regions.

[0041] If the white area extraction unit 101 does not extract white areas from all the partition areas included in the image to be output (NO in S3), the control unit 100 causes the image forming unit 12 to form an image using the image to be output acquired in S1 (S15).

[0042] On the other hand, if the white region extraction unit 101 extracts one or more white regions from the divided regions included in the image to be output (YES in S3), the high-brightness region extraction unit 102 extracts divided regions adjacent to the determined white region from each divided region included in the image to be output (S4). Here, in the example shown in FIG. 4, the divided regions adjacent to the white region are a predetermined number of divided regions adjacent to the white region lined up in the x direction and a predetermined number of divided regions lined up in the y direction. Furthermore, the predetermined number refers to, for example, if the determined white region is made up of multiple divided regions lined up in the x direction, the number of divided regions that make up the white region lined up in the x direction. If the determined white region is made up of multiple divided regions lined up in the y direction, the predetermined number refers to the number of divided regions that make up the white region lined up in the y direction.

[0043] Next, the high-brightness region extraction unit 102 extracts the adjacent divided region in the x and y directions that is configured with an image having a higher brightness, i.e., a high-brightness region (S5). A high-brightness region configured with an image having a higher brightness is, for example, the adjacent divided region in the x and y directions that has a higher average pixel value of the pixel group that configures the image of the divided region.

[0044] Then, the color change determination unit 103 determines whether the change in pixel values ​​of the image constituting the high-brightness area extracted by the high-brightness area extraction unit 102 toward the adjacent white area is (i) a change from high-brightness to low-brightness, (ii) a change from low-brightness to high-brightness, or (iii) neither (i) nor (ii) (S6).

[0045] In addition, (i) the change from high brightness to low brightness means the change from high brightness to low brightness in the white area, as shown in the example of Figure 5. in the y direction When high-brightness areas are adjacent to each other, the average value of the pixel values ​​of each column aligned in the y direction among the pixel groups that make up the image forming the high-brightness areas is y This refers to a state in which the pixel values ​​change from high to low in the direction toward the white area, for example, when an approximation curve of the average pixel values ​​of each column, column 1, column 2, etc., is calculated and the approximation curve slopes downward toward the white area. Note that it is preferable that the average pixel value of the column closest to the white area is the lowest among the average pixel values ​​of each column.

[0046] Here, (ii) a change from low luminance to high luminance means a change from low luminance to high luminance in the white area, as shown in the example of Figure 6. in the y direction When high-brightness areas are adjacent, among the pixel groups that make up the image that forms the high-brightness area, x In the direction Stretch The average value of each pixel in a row of pixels is y Calculate for each column in the direction, of The average pixel value is y The state where the value is changing from low to high in the direction toward the white area say. For example, this refers to a state in which an approximation curve of the average pixel values ​​of each column is calculated, and the approximation curve slopes upward toward the white region. Note that it is preferable that the average pixel value of the column closest to the white region is the highest among the average pixel values ​​of each column.

[0047] The color change determination unit 103 determines whether the white area is in the x direction When high-brightness areas are adjacent, among the pixel groups that make up the image that forms the high-brightness area, yThe average value of each pixel in a row of pixels aligned in the direction is x The average value of the pixel values ​​of each column is calculated as follows: x For the white area, based on whether the direction is changing from low to high or from high to low. y In the same manner as when high-luminance areas are adjacent in the direction, it is determined whether the above-mentioned cases (i) and (ii) apply.

[0048] Then, when the color change determination unit 103 determines that the image of the high-luminance region has changed from high luminance to low luminance ((i) in S6), the region generation unit 104 copies a part of the high-luminance side of the high-luminance region in a predetermined direction and generates an adjustment white region of a size that matches the size of the white region (S7). Here, the high-luminance side refers to the side of the high-luminance region that is higher in luminance than the region that is the edge of the white region (for example, a region having a width of, for example, 10 to 20% of the entire high-luminance region). The predetermined direction refers to the x direction when the high-luminance region is adjacent to the white region in the x direction, and the y direction when the high-luminance region is adjacent to the white region in the y direction. Also, the part of the region that becomes the high-luminance side refers to the part of the high-luminance region that is in the predetermined direction (in FIG. 7, y The white adjustment region is a region on the high-luminance side in the predetermined direction, and has a width of, for example, 30% of the entire high-luminance region in the predetermined direction. The region generating unit 104 copies this region from the high-luminance region and generates an adjustment white region by enlarging it to a size (width) that matches the size (width) of the white region in the predetermined direction.

[0049] Then, as shown in the example of FIG. 8, the image regenerator 105 replaces the white area with the adjustment white area generated by the area generator 104, and regenerates the image that constitutes each divided area (S8).

[0050] On the other hand, when the color change determination unit 103 determines that the image in the high-luminance region has changed from low to high luminance ((ii) in S6), as shown in the example of FIG. 9, the region generation unit 104 generates an adjustment white region by the same process as in S7 (S9), and then generates an inverted adjustment white region by inverting the high-luminance side and low-luminance side of the adjustment white region (S10). Then, as shown in the example of FIG. 10, the region generation unit 104 copies a part of the region in the inverted adjustment white region that is on the low-luminance side in the above-mentioned predetermined direction to generate a correction white region (S11). In addition, the part of the region that is on the low-luminance side is the region in the inverted adjustment white region where a low-luminance image exists, and is inverted in the above-mentioned predetermined direction. White for inversion adjustment The area generating unit 104 generates the area portion having a width of, for example, 30% of the entire area. White for inversion adjustment A correction white area is generated by copying from the area.

[0051] Next, as shown in an example in Figure 11, the image regeneration unit 105 replaces the inversion adjustment white area with a white area (S12), and replaces the correction white area with an area portion of the same width as the correction white area that is adjacent to the white area in the high-brightness area, thereby regenerating the image to be output (S13).

[0052] Furthermore, when the color change determination unit 103 determines that "neither (i) nor (ii)" ((iii) in step S6), the control unit 100 executes the process of step S15. The above-mentioned processes from S1 to S15 are performed on all white areas and adjacent high-luminance areas included in the image to be output.

[0053] The control unit 100 causes the image to be output, which has been regenerated through the processes of S8 and S12, to be formed on recording paper by the image forming unit 12, or to be stored in a storage medium such as the storage unit 26. Alternatively, the control unit 100 transmits the image to an external computer or the like via the communication unit 15.

[0054] As described above, when the output target image is regenerated in S8, at the boundary between the adjustment white region and the adjacent high-luminance region, in the direction from the high-luminance region toward the adjustment white region, or when the output target image is regenerated in S12, at the boundary between the correction white region and the inverted adjustment white region in the high-luminance region, in the direction from the correction white region toward the inverted adjustment white region, pixel values ​​temporarily decrease to low luminance pixel values ​​on the high-luminance region (correction white region) side and then increase to high luminance pixel values ​​on the adjustment white region (inverted adjustment white region), causing a sudden change in image brightness, as shown in the example in Figure 12. As a result, due to the Craik-O'Brien-Cornsweet illusion, the adjustment white region (inverted adjustment white region) appears to the viewer to be brighter (higher luminance) than the adjacent high-luminance region (correction white region). For this reason, even though the adjustment white area (inverted adjustment white area) is expressed in color using the pixel values ​​of pixels in the high-brightness area (correction white area), it is perceived by the viewer as a color closer to white than the high-brightness area (correction white area).

[0055] Therefore, according to this embodiment, it is possible to achieve color representation that approximates a white image by using only the color toners for general color image formation and the image formation mechanism using the color toners, without using white toner. Furthermore, in this embodiment, by representing colors using pixel values ​​of pixels in a high-brightness region (correction white region), that is, by representing colors that are close to white using colored inks for color image formation that are not white, even when forming an image on a colored recording medium, it is possible to form an image consisting of colors that are close to white as described above, and to allow a viewer to view an image consisting of colors that approximate a white image.

[0056] Next, a second embodiment of white representation processing performed on an image to be output will be described. The white representation processing according to the second embodiment is suitable for forming an image on a colored recording medium. Fig. 13 is a block diagram showing the internal configuration of an image forming apparatus 1 used to perform the white representation processing according to the second embodiment.

[0057] As shown in FIG. 13, the control unit 10 further functions as a background color information acquisition unit 106 and a reconstruction unit 107 by the image processing program stored in the ROM or memory unit 26 being executed by the processor.

[0058] The background color information acquisition unit 106 acquires background color information indicating the background color of recording paper used for image formation. For example, based on a user's operation of the operation unit 21, background color information indicating the background color of recording paper used for image formation by the image forming unit 12 is received by the operation unit 21. The background color information acquisition unit 106 acquires the background color information from the operation unit 21. The background color information is a predetermined color, such as yellow, magenta, cyan, red, blue, or beige.

[0059] The reconstruction unit 107 reconstructs the image to be output using pixel values ​​obtained by subtracting from the pixel values ​​of the image to be output the pixel values ​​indicating the background color indicated by the background color information acquired by the background color information acquisition unit 106. The reconstruction unit 107 stores predetermined pixel values ​​for each color indicated by the background color information.

[0060] 14 is a flowchart showing a second embodiment of white representation processing performed on an image to be output. Hereinafter, the white representation processing according to the second embodiment will be described with reference to FIG.

[0061] In the white expression process according to the second embodiment, first, the white region extraction unit 101 extracts a white region from the image reading unit 1. 1 The image data generated by the image forming apparatus 10 or image data (print target data) received from an external computer or the like via the communication unit 15 is acquired as an image to be output (S1).

[0062] Next, the reconstruction unit 107 identifies a predetermined pixel value indicating the background color indicated by the background color information acquired by the background color information acquisition unit 106, and reconstructs the image to be output using pixel values ​​obtained by subtracting the predetermined pixel value from the pixel values ​​of the image to be output (S22). FIG. 15 shows an example of this reconstruction. FIGS. 15(A), 15(B), and 15(C) show pixel values ​​of each pixel for the magenta color component of the CMYK values ​​when the background color indicated by the background color information acquired by the background color information acquisition unit 106 is magenta. Note that in FIG. 15, pixel values ​​are expressed as numerical values ​​ranging from a minimum of 0 to a maximum of 255. In this example, the predetermined pixel value for magenta is assumed to be "100."

[0063] If the background color indicated by the background color information is magenta, its default value is a pixel value of 100 (FIG. 15(B)), and the pixel values ​​of each pixel of the magenta color component of the CMYK values ​​for the image to be output are as shown in FIG. 15(A), when the image to be output is formed on recording paper, the recording paper itself will express a magenta color having a pixel value of 100, so the reconstruction unit 107 reconstructs the pixel values ​​of each pixel for the magenta color component as shown in FIG. 15(C) using pixel values ​​obtained by subtracting the default pixel value of 100 from the pixel values ​​of each pixel of the magenta color component of the image to be output. FIG. 15(C) also shows a case where the pixel values ​​are negative, but because pixel values ​​consisting of these negative values ​​cannot be expressed using CMYK inks, the reconstruction unit 107 converts pixel values ​​consisting of these negative values ​​to pixel values ​​of 0.

[0064] After the reconstruction process in S22, the processes from S2 onward are performed in the same manner as in the first embodiment. That is, in the second embodiment, white representation processing is performed based on the reconstructed output target image. Then, after the processes of S13, S8, and S15, the control unit 100 causes the image forming unit 12 to form an image of the output target image that has been subjected to the white representation processing (S23).

[0065] When forming an image on color recording paper, since the recording paper is colored magenta or the like, it is difficult to express a white color brighter than the background color on the recording paper based on the image to be output. However, even in the second embodiment, the above-mentioned white color expression processing allows an image made of a color close to white to be formed in the white area, allowing the viewer to view an image made of a color expression that approximates the white image.

[0066] Therefore, according to the second embodiment, by forming an image using an output target image that has been subjected to white representation processing based on the reconstructed output target image, it is possible to form an image with better reproducibility by taking into account the color components represented by the recording paper itself, and further, even when forming an image on color recording paper, an image made of a color close to white can be formed, allowing the viewer to view an image made of a color representation that approximates the white image.

[0067] According to the white representation processing of the first and second embodiments, when the above-described white representation processing is performed on a white area and an adjacent high-luminance area in an image to be output, as shown in Fig. 16, the white areas present in various places in the image to be output as shown in Fig. 16(A) are converted into adjustment white areas (inverted adjustment white areas) as shown in Fig. 16(B), and are perceived as brighter (higher luminance) than the adjacent high-luminance areas (correction white areas). Therefore, although the adjustment white areas (inverted adjustment white areas) are not completely white, they are perceived by the viewer as a color that is closer to white.

[0068] The white representation process according to the first embodiment can be applied not only to the inkjet image forming apparatus 1 described above, but also to an electrophotographic image forming apparatus. The white representation process according to the second embodiment is applied to the inkjet image forming apparatus 1 described above. The white representation process according to the second embodiment is a process suitable for forming an image on recording paper, but can also be applied to generating an output image when the output image that has undergone the white representation process is stored in the storage unit 26 or transmitted to another device via the communication unit 15.

[0069] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. Furthermore, the configuration and processing shown in the above embodiment using Figures 1 to 16 are merely one embodiment of the present invention, and the present invention is not intended to be limited to these configurations and processing. [Explanation of symbols]

[0070] 1. Image forming device 100 control section 101 White area extraction part 102 High-brightness area extraction unit 103 Color change determination unit 104 Area generator 105 Image Regeneration Unit 106 Background color information acquisition unit 107 Reconstruction part

Claims

1. an image forming unit that forms an image on a recording medium; a white area extraction unit that extracts a white area composed of a white image for each predetermined divided area from the image to be output; a high-brightness region extraction unit that extracts, from the output target image, a high-brightness region that is configured with an image having a higher brightness from among divided regions adjacent to the white region extracted by the white region extraction unit; a color change determination unit that determines whether a change in pixel value of an image within a high-luminance region extracted by the high-luminance region extraction unit is a change from low luminance to high luminance or a change from high luminance to low luminance toward the adjacent white region; an area generating unit that, when the color change determining unit determines that the image of the high-luminance area has changed from high luminance to low luminance, copies a part of the high-luminance side of the high-luminance area and generates an adjustment white area having a size that matches the size of the white area; an image regeneration unit that replaces the white area with the adjustment white area generated by the area generation unit and regenerates the image to be output; a control unit that causes the image forming unit to form the output target image regenerated by the image regeneration unit on a recording medium.

2. The area generation unit When the color change determination unit determines that the image of the high-luminance region has changed from low luminance to high luminance, a part of the high-luminance region on the high-luminance side is copied to generate an adjustment white region having a size that matches the size of the white region, generating an inverted white adjustment area by inverting the high-luminance side and the low-luminance side of the white adjustment area; A part of the area on the low-luminance side of the inversion adjustment white area is copied to generate a correction white area; The image regeneration unit replacing the inversion adjustment white area with the high-luminance area; The image forming apparatus according to claim 1 , wherein the image to be output is regenerated by replacing the white area for correction with a portion of the high-luminance area adjacent to the white area.

3. a background color information acquisition unit that acquires background color information indicating a background color of the recording medium, the image forming unit forms an image using an inkjet method, a reconstruction unit that reconstructs the image to be output using pixel values ​​obtained by subtracting pixel values ​​indicating a background color indicated by the background color information acquired by the background color information acquisition unit from pixel values ​​of the image to be output, 3. The image forming apparatus according to claim 1, wherein the high-brightness region extraction unit, the high-brightness region extraction unit, the color change determination unit, the region generation unit, and the image regeneration unit perform processing using the output target image reconstructed by the reconstruction unit.

4. a white area extraction unit that extracts a white area composed of a white image for each predetermined divided area from the image to be output; a high-brightness region extraction unit that extracts, for each divided region from the output target image, a high-brightness region that is configured with an image having a higher brightness from among divided regions adjacent to the white region extracted by the white region extraction unit; a color change determination unit that determines whether a change in pixel value of an image within a high-luminance region extracted by the high-luminance region extraction unit is a change from low luminance to high luminance or a change from high luminance to low luminance toward the adjacent white region; an area generating unit that, when the color change determining unit determines that the image of the high-luminance area has changed from high luminance to low luminance, copies a part of the high-luminance side of the high-luminance area and generates an adjustment white area having a size that matches the size of the white area; an image regeneration unit that replaces the white area with the adjustment white area generated by the area generation unit and regenerates the image to be output; an image processing program that causes a computer to operate as a control unit that causes the image forming unit to form the output target image regenerated by the image regeneration unit on a recording medium;

5. The region generation unit When the color change determination unit determines that the image of the high-luminance region has changed from low luminance to high luminance, a part of the high-luminance region on the high-luminance side is copied to generate an adjustment white region having a size that matches the size of the white region, generating an inverted white adjustment area by inverting the high-luminance side and the low-luminance side of the white adjustment area; A part of the area on the low-luminance side of the inversion adjustment white area is copied to generate a correction white area; The image regeneration unit replacing the inversion adjustment white area with the high-luminance area; The image processing program according to claim 4 , further causing the computer to operate so as to replace the white correction area with a portion of the high-brightness area adjacent to the white area, and to regenerate the image to be output.

Images