JP5907474B2 - Image forming apparatus and program - Google Patents

Description

  The present invention relates to an image forming apparatus and a program.

  In Patent Document 1, the read image is reproduced for each of the plurality of color element groups, and the accuracy is determined for each of the plurality of color element groups according to the area occupied by the color portion outside the gamut in the reproduced image. The calculation is described.

JP 2008-22149 A

  The object of the present invention is to reduce the image data out of the reproduced image and the image data out of the actually printed image even when the area occupied by the image data out of the gamut is small. It is an object to provide an image forming apparatus and a program that can suppress the color difference.

  The invention described in claim 1 includes a first printing unit that prints an image using a plurality of color developers, and a plurality of colors including colors different from the color of the developer used by the first printing unit. When the second printing unit that prints an image using the developer and the image data of at least a part of the image to be printed are out of the first color gamut that can be reproduced by the first printing unit, Based on the number of pixels of the deviated image data and the distance from each pixel of the deviated image data to the outline of the first color gamut, each of the pixels of the deviated image data and the first color gamut A first evaluation unit that evaluates a gap between the first printing unit and a first determination unit that determines whether to print by the first printing unit or the second printing unit based on the evaluation by the first evaluation unit. An image forming apparatus comprising: .

  The invention according to claim 2 of the present application is the image forming apparatus according to claim 1, wherein the second printing unit uses a developer obtained by adding at least one color to the developer used by the first printing unit. Is an image forming apparatus.

  The invention according to claim 3 of the present application is the invention according to claim 1 or 2, wherein the first printing means prints an image using a developer of at least two colors of yellow, magenta, cyan and black. The second printing unit is an image forming apparatus that prints an image using a developer of at least one of yellow, magenta, cyan, and black and at least one of orange, green, and violet. .

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the image to be printed is out of the first color gamut based on the determination by the first determination means. Based on the number of pixels of the image data and the distance from the pixels of the deviated image data to the outline of the second color gamut, the distance between each pixel of the deviated image data and the second color gamut A second evaluation unit that evaluates whether the first printing unit or the second printing unit performs printing based on the evaluation by the second evaluation unit; The image forming apparatus further includes:

  According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the first evaluating means includes the pixels of the image data out of the first color gamut in the image to be printed, and the first A value obtained by multiplying the distance from the pixel of the deviated image data to the outer surface of the first color gamut by the number of pixels of the deviated image data as a first evaluation value representing the distance from the one color gamut The first determination means determines that printing is performed by the first printing means when the first evaluation value is not more than a preset threshold value, and the second evaluation means When the evaluation value of 1 is larger than the threshold value, the second evaluation value representing the distance between each pixel of the deviated image data and the second color gamut is used as the second evaluation value from the deviated image data pixel. Multiply the distance to the outline of the color gamut by the number of pixels of the out-of-range image data When the second evaluation value is larger than the threshold value, the second determination unit determines that printing is performed by the first printing unit, and the second evaluation value is equal to or less than the threshold value. In this case, the image forming apparatus determines that printing is performed by the second printing unit.

  The invention according to claim 6 of the present application is the first aspect of the invention according to any one of claims 1 to 5, wherein the input image data is converted into image data expressed in a color space independent of the input source. Color conversion means and second color conversion for converting the image data converted by the first color conversion means into image data expressed in a color space made up of developer colors used by the first printing means And when the image data converted by the second color conversion unit is out of the first color gamut, the first evaluation unit Evaluating the distance between the pixel of the out-of-image data and the first color gamut based on the number of pixels and the distance from each pixel of the out-of-image data to the outline of the first color gamut. The image forming apparatus is characterized.

  The invention according to claim 7 of the present application is the invention according to claim 5, wherein the first evaluation means deviates from the first color gamut of the image to be printed as the first evaluation value. Obtaining a value obtained by multiplying the length of the perpendicular when the perpendicular is drawn on the contour surface of the first color gamut from the image data by the number of pixels of the image data deviated, and the second evaluation means, As a second evaluation value, a value obtained by multiplying the length of the perpendicular when the perpendicular is drawn on the contour surface of the second color gamut from the out-of-order image data by the number of pixels of the out-of-image data. An image forming apparatus characterized by the above.

  The invention according to claim 8 of the present application is the invention according to claim 5 or 6, wherein the first evaluation means finally obtains a value obtained by multiplying the first evaluation value by a preset weight value. In the image forming apparatus, the first evaluation value is used, and the second evaluation unit uses a value obtained by multiplying the second evaluation value by the weight value as a final second evaluation value. .

  The invention according to claim 9 of the present application is the first aspect of the invention according to any one of claims 4 to 8, wherein the first printing means calculates costs for a plurality of developers used for printing an image. Calculating means, a second calculating means for calculating costs for a plurality of developers used for printing an image by the second printing means, a determination result by the first determining means, the second determining means, Whether printing is performed by the first printing unit or the second printing unit using the determination result of the determination unit, the calculation result of the first calculation unit, and the calculation result of the second calculation unit. The image forming apparatus further includes selection means for prompting selection.

  According to a tenth aspect of the present invention, in an image forming apparatus including a computer, a first printing step for printing an image using a plurality of colors of developer, and a color of the developer used in the first printing step A second printing step for printing an image using a plurality of colors of developer including different colors, and at least a part of the image data of the image to be printed can be reproduced by the first printing step. In the case of deviating from one color gamut, the deviated image data pixels based on the number of pixels of the deviating image data and the distance from each pixel of the deviating image data to the outline of the first color gamut. A first evaluation step for evaluating a gap between the first color gamut and the first printing unit and the second printing unit based on the evaluation by the first evaluation step. Is a program for causing to execute a first determination step of determining in the computer or.

  According to the first aspect of the present invention, it is possible to appropriately print even when there is image data out of the color gamut, compared to the case without the present configuration.

  According to the second aspect of the present invention, it is possible to print by enlarging the color gamut by the first printing means as compared with the case where this configuration is not provided.

  According to the third aspect of the present invention, it is possible to print by enlarging the color gamut by the first printing means as compared with the case without this configuration.

  According to the fourth aspect of the present invention, it is possible to select a color gamut suitable for reproducing the spot color outside the gamut in the reproduced image, as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, it is possible to perform printing while suppressing the consumption of the developer when reproducing the spot color.

  According to the sixth aspect of the present invention, compared to the case without this configuration, the input image data is expressed in a color space composed of process data and image data expressed in a color space independent of the input source. And image data expressed in a color space composed of process colors and special colors.

  According to the seventh aspect of the present invention, even when the area occupied by the image data out of the color gamut is small compared to the case without this configuration, the image data out of the color gamut is actually printed. Therefore, it is possible to suppress the color difference between the image data and the deviated image data.

  According to the eighth aspect of the present invention, even when the area occupied by the image data out of the color gamut is small compared to the case without this configuration, the image data out of the color gamut is actually printed. Therefore, it is possible to suppress the color difference between the image data and the deviated image data.

  According to the present invention of claim 9, even when the area occupied by the image data out of the color gamut is small compared to the case without this configuration, the image data out of the color gamut is actually printed. Therefore, it is possible to suppress the color difference between the image data and the deviated image data.

  According to the tenth aspect of the present invention, it is possible to appropriately print even when there is image data out of the color gamut, compared to a case where the present configuration is not provided.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the control program which operate | moves with the control part of FIG. It is a figure which shows an example of a YMCK gamut. It is a figure which shows an example of a YMCKOGV gamut. It is a flowchart which shows the process of the control program of FIG.

Embodiments of the present invention will be described below. In addition, the following description is only an example in implementing this invention, and this invention is not necessarily limited to the matter demonstrated below, It can change suitably as needed.
For example, the control program and the image data to be printed are described below as being stored in a storage medium in the control unit. However, the control program and the image data to be printed are connected to the hard disk in the image forming apparatus or the image forming apparatus via a network. It may be stored in a database or the like.

FIG. 1 is a diagram illustrating an image forming apparatus 1 according to an embodiment of the present invention.
In FIG. 1, the image forming apparatus 1 includes an apparatus main body 10, an operation panel 20 mounted on the apparatus main body 10, a scanner 30, and a paper feeding device 40.
Hereinafter, the image forming apparatus according to the embodiment of the present invention will be described as a printer, but other apparatuses (for example, a facsimile machine and a multifunction machine) may be used.

In the following drawings, n does not always indicate the same number, and substantially the same components are denoted by the same reference numerals.
Hereinafter, when any one of a plurality of constituent parts such as “toner image forming units 102Y, 102M, 102C, 102K, 102O, 102G, and 102V” is indicated without being specified, simply “toner image forming unit 102” is shown. Or the like.

The apparatus main body 10 includes a control unit 100, a toner image forming unit 102, an intermediate transfer belt 104, a transfer roll 106, a fixing unit 108, a paper conveyance path 110, a conveyance roller 112, and a discharge tray 114.
The control unit 100 is a control board including a storage medium such as a memory and a processor, for example. A control program 12 is stored in a storage medium such as a memory. In the control unit 100, the processor body 10 is controlled by the processor reading and executing the control program 12 from a storage medium such as a memory. Details of the control program 12 will be described later.

The toner image forming unit 102 is provided for each color constituting the color image.
Here, a color image is composed of process colors such as yellow (Y), magenta (M), cyan (C), and black (K), and special colors such as orange (O), green (G), and violet (V). The toner image forming units 102Y, 102M, 102C, 102K, 102O, 102G, and 102V are provided, but the colors constituting the color image are not limited to these colors.
For example, a color image may be composed of two (or three) of the process colors, or a color image may be composed of at least one of the process colors and one (or two) of the special colors. May be. When a color image is composed of Y, C, and B of the process colors and O and G of the special colors, toner image forming units 102Y, 102C, 102B, 102O, and 102G are provided.
Further, for example, red (R), green (G), and blue (B) may be featured. When a color image is formed by the process colors and these special colors, toner image forming units 102Y, 102M, 102C, 102K, 102R, 102G, and 102B are provided.
For example, the process color is a toner color that is basic in printing, and the special color is a toner color formulated to express a color that cannot be reproduced by the process color.

  The toner image formed by the toner image forming unit 102 is transferred to the intermediate transfer belt 104 and then transferred to a sheet at a position facing the toner image forming unit 102 by the transfer roll 106. The sheet on which the toner image is transferred by the transfer roll 106 is conveyed to the fixing unit 108 through a sheet conveyance path 110 in which a plurality of sets of conveyance rollers 112 are arranged. The fixing unit 108 fixes the toner image transferred to the paper. The paper thus subjected to the printing process is discharged to the discharge tray 114 with the printing surface facing down.

The operation panel 20 receives an instruction (print instruction) for executing a printing process based on the image data read by the scanner 30 from the user, and transmits the received instruction to the control unit 100.
Here, the print instruction is to execute print processing based on the image data read by the scanner 30, but the present invention is not limited to this. For example, after being read by the scanner 30, print processing is executed based on image data once stored in a memory or the like, or print processing is executed based on image data transmitted from a client PC connected via a network. The printing process may be executed based on the image data once stored in the memory or the like after being transmitted from the client PC or the like.

Further, the operation panel 20 displays information related to the combination of colors used for image printing, receives an instruction (selection instruction) for selecting one of the color combinations from the user, and transmits the received instruction to the control unit 100. To do.
The combination of colors used for printing an image is, for example, a combination of process colors and a combination of process colors and special colors. Here, Y, M, C, K and Y, M, C, K, O, G, V. As will be described later, the information regarding the combination of these colors includes, for example, a calculation result of the cost of printing an image when using these color combinations, and at least an image using any of process colors and spot colors. This is a determination result as to whether or not a part is printed.
Although not shown, the operation panel 20 is communicably connected to the control unit 100 via a cable and a connector.

The scanner 30 reads a set original and transmits the read contents to the control unit 100 as image data. The image data transmitted to the control unit 100 is expressed in a color space depending on the scanner 30 and is expressed in the RGB color space here.
Although not illustrated, the scanner 30 is communicably connected to the control unit 100 via a cable and a connector.

The sheet feeding device 40 includes a sheet feeding tray 400, a sheet feeding head 402, and a sheet feeding path 404.
The paper in the paper feed tray 400 is supplied to the apparatus main body 10 through a paper feed path 404 in which a plurality of sets of transport rollers 112 are arranged according to the operation of the paper feed head 402. Here, only one paper feed tray 400 and one paper feed head 402 are provided, but a plurality of each may be provided.
Although not shown, a part of the side surface of the paper feeding device 40 on the apparatus body 10 side is used as a guide surface for communicating the paper feeding path 404 with the paper transport path 110.

FIG. 2 is a diagram showing the configuration of the control program 12 that operates in the control unit 100 of FIG.
As illustrated in FIG. 2, the control program 12 includes a reception unit 120, a storage unit 122, a first color conversion unit 124, a second color conversion unit 126, a first calculation unit 128, and a third color conversion unit 130. 1 includes a second calculation unit 132, a first determination unit 134, a second determination unit 136, a third determination unit 138, a first control unit 140, and a second control unit 142. The process is triggered by the transmission of a print instruction from the panel 20 as a trigger.

[Reception unit 120]
The accepting unit 120 accepts the image data transmitted from the scanner 30 in FIG. 1 based on the print instruction transmitted from the operation panel 20 and outputs the image data to the first color converting unit 124. As described above, this image data is expressed in the RGB color space.
The image data received by the receiving unit 120 may be image data stored in a memory or the like, or image data transmitted from a client PC or the like.

[Storage unit 122]
The storage unit 122 stores device profiles, gamuts, weight values, threshold values, and toner unit prices.
Details of each of these data will be described below.

The device profile includes an input device profile and an output device profile. Here, the input device profile is a lookup for generating image data in an L ^* a ^* b ^* color space that does not depend on a device from image data expressed in an RGB color space that depends on an input device such as the scanner 30. It is a table (LUT: LookUpTable). Hereinafter, this LUT is referred to as “L ^* a ^* b ^* color space LUT”.
Here, the output device profile is an LUT for generating image data in the color space for the output device from image data in the L ^* a ^* b ^* color space. As described above, here, since the toner image forming units 102Y, 102M, 102C, 102K, 102O, 102G, and 102V are provided as output devices, the output device profile is used to generate image data in the CMYK color space. LUT (that is, LUT for generating image data of process color space) and LUT for generating image data of CMYKOGV color space (that is, for generating image data of process color and spot color space) LUT). Hereinafter, these LUTs are referred to as “CMYK color space LUT” and “CMYKOGV color space LUT”.

The gamut is a color area (color gamut) that can be reproduced by the output device. Here, toner image forming units 102Y, 102M, 102C, 102K, 102O, 102G, and 102V are provided as output devices, and process colors Y, M, C, and K and spot colors O, G, and V can be reproduced. Therefore, the gamuts are Y, M, C, K gamuts (that is, process color gamuts) and Y, M, C, K, O, G, V gamuts (that is, process colors and spot color gamuts). is there. Hereinafter, these gamuts are referred to as “YMCK gamut” and “YMCKOGV gamut”.
FIG. 3 is a diagram illustrating an example of the YMCK gamut. FIG. 4 is a diagram illustrating an example of the YMCKOGV gamut. The shaded portion in FIG. 4 indicates an area enlarged from the YMCK gamut in FIG. The gamut of FIG. 4 includes the gamut of FIG. 3 and is enlarged from the gamut of FIG.

The weight value and the threshold value are preset by the user. For example, for a highly important color such as a corporate color used for a company logo mark, a weighting value larger than that of other colors is set.
The unit price of toner is a unit price of toner used by the toner image forming unit 102 in FIG. 1, and is set in advance by the user. Here, since toner image forming units 102Y, 102M, 102C, 102K, 102O, 102G, and 102V are provided, the unit price of yellow toner, the unit price of magenta toner, the unit price of cyan toner, the unit price of black toner, the unit price of orange toner, The unit price of green toner and the unit price of violet toner are set.
Note that the weighting value, threshold value, and toner unit price may be designated by the user at the time of printing, and may be received from the user via the operation panel 20 as part of the printing instruction, for example.

[First color conversion unit 124]
The first color conversion unit 124 uses the L ^* a ^* b ^* color space LUT read from the storage unit 122 to convert the image data in the L ^* a ^* b ^* color space from the image data output from the reception unit 120. Generated and output to the second color conversion unit 126 and the third color conversion unit 130.

[Second color conversion unit 126]
The second color conversion unit 126 uses the CMYK color space LUT read from the storage unit 122 to generate CMYK color space image data from the image data output from the first color conversion unit 124. The data is output to the calculation unit 128, the first determination unit 134, and the second control unit 142.

[First calculation unit 128]
The first calculation unit 128 calculates the cost for the toner used to execute the printing process based on the image data output from the second color conversion unit 126 and outputs the cost to the first control unit 140.
Specifically, the first calculation unit 128 stores the usage amount of toner used by the apparatus main body 10 of FIG. 1 for executing print processing based on the image data output from the second color conversion unit 126. The toner cost is calculated by multiplying the unit price of the toner read from the unit 122.
As described above, since the image data output from the second color conversion unit 126 is image data in the CMYK color space, the first calculation unit 128 performs the processing for each of yellow toner, magenta toner, cyan toner, and black toner. The cost is calculated, and the total value of the costs is calculated as the final cost.

[Third color conversion unit 130]
The third color conversion unit 130 uses the CMYKOGV color space LUT read from the storage unit 122 to generate image data in the CMYKOGV color space from the image data output from the first color conversion unit 124, and The data is output to the calculation unit 132 and the second control unit 142.

[Second calculation unit 132]
The second calculation unit 132 calculates the cost associated with the toner used to execute the printing process based on the image data output from the third color conversion unit 130 and outputs the cost to the first control unit 140.
Specifically, the second calculation unit 132 stores the amount of toner used by the apparatus main body 10 in FIG. 1 to execute the printing process based on the image data output from the third color conversion unit 130. The toner cost is calculated by multiplying the unit price of the toner read from the unit 122.
As described above, since the image data output from the third color conversion unit 130 is image data in the CMYKOGV color space, the second calculation unit 132 performs yellow toner, magenta toner, cyan toner, black toner, orange Costs are calculated for each of the toner, green toner, and violet toner, and the total value of the costs is calculated as the final cost.

[First determination unit 134]
The first determination unit 134 determines whether the image data output from the second color conversion unit 126 is within the YMCK gamut read from the storage unit 122. In order to reduce the processing load, determination may be made for some of the pixels instead of determining all of the pixels constituting the image data. For example, a part of pixels can be determined by skipping the rows constituting the image data and the pixels constituting the rows.
The first determination unit 134 determines that the pixels in the YMCK gamut should be printed using the process color. It should be noted that further determination (determination by the second determination unit 136) is performed on the pixels outside the YMCK gamut.

[Second determination unit 136]
The second determination unit 136 evaluates (numerizes) the distance from the outline of the YMCK gamut for each pixel determined to be outside the YMCK gamut by the first determination unit 134, and stores the numerical value. It is determined whether or not the threshold value is larger than the threshold value read from the unit 122. Although the threshold value has been described as being a fixed value set in advance, it is not necessarily a fixed value and may be a variable value.
Hereinafter, a value obtained by quantifying the distance between each pixel determined to be outside the YMCK gamut by the first determination unit 134 and the outline of the YMCK gamut is referred to as a “first evaluation value”.

As the first evaluation value, for example, the length of a perpendicular when a vertical line is dropped from the pixel determined to be outside the YMCK gamut onto the outer surface of the YMCK gamut (the image data determined to be outside the YMCK gamut). The minimum distance between the outer surface of the pixel and the YMCK gamut is calculated.
When there are pixels with the same pixel value, or when there are pixels whose pixel values are close to each other, such as when the difference in pixel values is within the threshold value read from the storage unit 122, the total pixel value (or pixels) A value obtained by multiplying one of the values by the number of pixels) is calculated as a first evaluation value of a pixel group including a plurality of pixels having the same or similar pixel value.
The first evaluation value calculated in this way may be multiplied by the weighting value read from the storage unit 122 to obtain the final first evaluation value.

For example, if the pixels of the image data determined to be outside the YMCK gamut are P ₁ , P ₂ ,..., P _n , the minimum distance Δ (delta) E ₁ between the outer surface of P ₁ and the YMCK gamut, minimum distance △ _(delta) E 2 of the outer surface of the P ₂ and YMCK gamut, ..., the minimum distance △ (delta) _{E n} of the outer surface of the _{P n} and YMCK gamut is calculated as a first evaluation value.
When the pixel value of the pixel values and P ₂ of P ₁ is the same or approximation, plus the first evaluation value △ (delta) E ₂ of P ₂ to the first evaluation value △ (delta) E ₁ P ₁ Δ (Delta) E ₁ + Δ (Delta) E ₂ (or Δ (Delta) E ₁ · 2) is calculated as the first evaluation value of the pixel group composed of P ₁ and P ₂ .
Δ (Delta) E ₁ multiplied by P ₁ weighted value W ₁ Δ (Delta) E ₁ · W ₁ , Δ (Delta) E ₂ multiplied by P ₂ weighted value W ₂ Δ (Delta) _{E 2 · W 2, ···,} △ be calculated as the final first evaluation value weighted value _{W n} multiplied by △ _(delta) E n · _{W n} of _{P n} to (delta) _{E n} Good.

  The second determination unit 136 determines that the pixel and the pixel group whose first evaluation value is equal to or less than the threshold value should be printed using the process color. It should be noted that a further determination (determination by the third determination unit 138) is made for pixels and pixel groups having the first evaluation value larger than the threshold value.

[Third determination unit 138]
The third determination unit 138 determines the distance from the outline of the YMCKOGV gamut read from the storage unit 122 for each pixel and pixel group determined by the second determination unit 136 that the first evaluation value is greater than the threshold value. Evaluation (numericalization) is performed, and it is determined whether or not the numerical value is larger than the threshold value read from the storage unit 122.
Hereinafter, a value obtained by quantifying the distance between the pixel and the pixel group for which the first evaluation value is determined to be larger than the threshold by the second determination unit 136 and the outline of the YMCKOGV gamut read from the storage unit 122 will be referred to as “first”. 2 ”.

As the second evaluation value, for example, the length of the perpendicular when the first evaluation value is dropped from the pixel and the pixel group determined to be larger than the threshold on the outer surface of the YMCKOGV gamut (outside the YMCK gamut). The minimum distance between the pixels of the image data determined to be present and the outer surface of the YMCKOGV gamut is calculated.
Furthermore, the final evaluation value may be obtained by multiplying the second evaluation value calculated in this way by the weighting value read from the storage unit 122.

For example, when the pixels for which the first evaluation value is determined to be greater than the threshold are P ₁ , P ₂ ,..., P _n , the minimum distance Δ (delta) e between the outer surfaces of P ₁ and YMCKOGV gamut _1, the minimum distance of the outer surface of the _{P 2} and YMCKOGV gamut △ _(delta) e 2, · · ·, the minimum distance △ (delta) _{e n} of the outer surface of the _{P n} and YMCKOGV gamut is calculated as the second evaluation value The
Further, Δ (delta) e ₁ multiplied by P ₁ weighted value W ₁ Δ (delta) e ₁ · W ₁ , Δ (delta) e ₂ multiplied by P ₂ weighted value W ₂ Δ (delta) _{e 2 · W 2, ···,} △ be calculated as the final second evaluation value weighted value _{W n} multiplied by △ _(delta) e n · _{W n} of _{P n} to (delta) _{e n} Good.
Here, the threshold used by the third determination unit 138 for calculating the second evaluation value is the same as the threshold used by the second determination unit 136 for calculating the table value, but may be different. Further, the weighting value used by the third determination unit 138 to calculate the second evaluation value may be the same as or different from the weighting value used by the second determination unit 136 to calculate the evaluation value.

The third determination unit 138 determines that the pixel and the pixel group having the second evaluation value equal to or larger than the threshold should be printed using the process color, and the pixel and the pixel group having the second evaluation value smaller than the threshold. Determines that the spot color should be used for printing. Here, the third determination unit 138 determines that the pixel and the pixel group whose second evaluation value is equal to or greater than the threshold should be printed using Y, M, C, and K, and the second evaluation value It is determined that pixels and pixel groups having a value smaller than the threshold value should be printed using Y, M, C, K, O, G, and V.
Although it has been described that the color used for printing is determined using the second evaluation value, the color difference from the YMCK gamut and the YMCKOGV gamut are determined for each pixel and pixel group for which the first evaluation value is determined to be greater than the threshold value. And the color used for printing may be determined based on the gamut for which the smallest color difference is calculated. For example, when the gamut for which the smallest color difference is calculated is the YMCK gamut, it is determined that printing should be performed using Y, M, C, and K.

[First control unit 140]
The first control unit 140 operates the calculation results by the first calculation unit 128 and the second calculation unit 132 and the determination results by the first determination unit 134, the second determination unit 136, and the third determination unit 138. While being displayed on the panel 20, the selection instruction transmitted from the operation panel 20 is received and output to the second control unit 142.

[Second control unit 142]
Based on the selection instruction output from the first control unit 140, the second control unit 142 executes print processing based on the image data output from the second color conversion unit 126 using the process color. The apparatus main body 10 is controlled, or the apparatus main body 10 is controlled to execute the printing process based on the image data output from the third color conversion unit 130 using the process color and the spot color.

FIG. 5 is a flowchart showing the processing of the control program 12 of FIG. As described above, the flowchart of FIG. 5 is started with a print instruction transmitted from the operation panel 20 of FIG. 1 as a trigger.
In addition, although the following steps are assumed to be executed sequentially, a certain step may be executed in parallel with another step. For example, steps 104 and 106 may be executed in parallel with steps 108 and 110.

As shown in FIG. 5, in step 100 (S <b> 100), the accepting unit 120 in FIG. 2 accepts the image data transmitted from the scanner 30 in FIG. 1 based on the print instruction transmitted from the operation panel 20.
In step 102 (S102), the first color conversion unit 124 in FIG. 2 uses the L ^* a ^* b ^* color space LUT to calculate the L ^* a ^* b ^* color space from the image data received in step 100. Generate image data.

In Step 104 (S104), the second color conversion unit 126 in FIG. 2 generates image data in the CMYK color space from the image data generated in Step 102 using the CMYK color space LUT.
In step 106 (S106), the first calculation unit 128 in FIG. 2 calculates the cost for the toner used to execute the printing process based on the image data generated in step 104.

In step 108 (S108), the third color conversion unit 130 in FIG. 2 generates image data in the CMYKOGV color space from the image data generated in step 102 using the CMYKOGV color space LUT.
In step 110 (S110), the second calculation unit 132 in FIG. 2 calculates the cost for the toner used to execute the printing process based on the image data generated in step.

In step 112 (S112), the first determination unit 134 of FIG. 2 determines whether the image data generated in step 104 is in the YMCK gamut.
The first determination unit 134 repeats the determination of whether or not each pixel constituting the image data generated in step 104 is in the YMCK gamut. However, as described above, the determination may not be repeated for all the pixels constituting the image data, but the determination may be repeated for some pixels.
The first determination unit 134 determines that the pixels in the YMCK gamut should be printed using the process color, and the process proceeds to step 118. For pixels outside the YMCK gamut, the process proceeds to step 114.

In step 114 (S114), the second determination unit 136 in FIG. 2 calculates a first evaluation value that represents a distance from the outline of the YMCK gamut for each pixel determined to be outside the YMCK gamut in step 112. Then, it is determined whether or not the first evaluation value is larger than a threshold value.
The second determination unit 136 repeatedly calculates a first evaluation value for each pixel determined to be outside the YMCK gamut and determines whether or not the first evaluation value is greater than a threshold value.
As described above, when the pixel values are the same or approximate, the first evaluation value is calculated for each pixel group including a plurality of pixels having the same or approximate pixel value, and the first evaluation value is calculated from the threshold value. The determination whether or not is larger is repeated.
The second determination unit 136 determines that the pixel and the pixel group whose first evaluation value is equal to or less than the threshold should be printed using the process color, and proceeds to the process of step 118. For pixels and pixel groups whose first evaluation value is greater than the threshold, the process proceeds to step 116.

In step 116 (S116), the third determination unit 138 in FIG. 2 represents the distance between the pixel and the pixel group determined to have the first evaluation value larger than the threshold value in step 114 and the outline of the YMCKOGV gamut. A second evaluation value is calculated, and it is determined whether or not the second evaluation value is smaller than a threshold value.
The third determination unit 138 calculates a second evaluation value representing a distance from the outline of the YMCKOGV gamut for each pixel and pixel group for which the second evaluation value is determined to be greater than the threshold value, It is repeated to determine whether or not the evaluation value is smaller than the threshold value.
The third determination unit 138 determines that the pixel and the pixel group having the second evaluation value equal to or larger than the threshold should be printed using the process color, and the pixel and the pixel group having the second evaluation value smaller than the threshold. Determines that printing is to be performed using the spot color, and the process proceeds to step 118.

In step 118 (S118), the first control unit 140 displays the calculation results in steps 106 and 110 and the determination results in steps 112, 114, and 116 on the operation panel 20, and the selection instruction transmitted from the operation panel 20. Accept.
In step 120 (S120), the second control unit 142 executes print processing based on the image data generated in step 104 using the process color based on the selection instruction received in step 118. 10 or the apparatus main body 10 is controlled to execute the printing process based on the image data generated in step 108 using the process color and the spot color.

As described above, when at least a part of image data of an image to be printed deviates from the process color gamut, the first evaluation representing a gap between the deviated image data and the process color gamut outline. The process color or the spot color is used to determine whether to print the image according to the value and the second evaluation value indicating the distance between the out-of-place image data and the outline of the process color and the spot color gamut. .
As a result, even if the area occupied by the image data that is out of the image is small, and it is generally determined that the image is printed using only the process color, it is determined that the image is printed using the special color. As a result, the color difference between the deviated image data and the deviated image data in the actually printed image is reduced. In particular, it is effective for a color having a large importance although it occupies a small area such as a corporate color used for a company logo mark.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Apparatus main body 100 Control part 12 Control program 120 Reception part 122 Storage part 124 1st color conversion part 126 2nd color conversion part 128 1st calculation part 130 3rd color conversion part 132 2nd Calculation unit 134 First determination unit 136 Second determination unit 138 Third determination unit 140 First control unit 142 Second control unit 20 Operation panel 30 Scanner 40 Paper feeding device

Claims (9)

First printing means for printing an image using a plurality of color developers;
Second printing means for printing an image using a plurality of color developers including a color different from the color of the developer used by the first printing means;
When image data of at least a part of an image to be printed is out of the first color gamut that can be reproduced by the first printing unit, the number of pixels of the out-of-image data and the out-of-image data pixels First evaluation means for evaluating a distance between each of the pixels of the deviated image data and the first color gamut based on a distance from each to an outline of the first color gamut;
First determination means for determining which of the first printing means and the second printing means to perform printing based on the evaluation by the first evaluation means;
Of the image to be printed, the number of pixels of the image data out of the first color gamut and the pixels of the image data out of the first color gamut to the outline of the second color gamut printable by the second printing unit. A second evaluation unit that evaluates a distance between each pixel of the deviated image data and the second color gamut based on a distance;
An image forming apparatus comprising: a second determination unit configured to determine which of the first printing unit and the second printing unit performs printing based on the evaluation by the second evaluation unit . The image forming apparatus according to claim 1, wherein the second printing unit prints an image using a developer obtained by adding at least one color to the developer used by the first printing unit. The first printing means prints an image using a developer of at least two colors of yellow, magenta, cyan and black,
The image forming apparatus according to claim 2, wherein the second printing unit prints an image using a developer of at least two colors of yellow, magenta, cyan, and black and at least one color of orange, green, and violet. The first evaluation means outputs a first evaluation value representing a distance between each pixel of image data out of the first color gamut and the first color gamut in an image to be printed. A value obtained by multiplying the distance from the pixel of the image data to the outer surface of the first color gamut by the number of pixels of the deviated image data;
The first determination unit determines that printing is performed by the first printing unit when the first evaluation value is equal to or less than a preset threshold value;
When the first evaluation value is larger than the threshold value, the second evaluation means uses the outlier as a second evaluation value that represents a distance between each pixel of the image data that has deviated and the second color gamut. A value obtained by multiplying the distance from the pixel of the image data to the outline of the second color gamut by the number of pixels of the deviated image data,
The second determination unit determines that printing is performed by the first printing unit when the second evaluation value is greater than the threshold value, and the second evaluation value is determined when the second evaluation value is equal to or less than the threshold value. The image forming apparatus according to claim 1, wherein the image forming apparatus determines that printing is performed by the printing unit. First color conversion means for converting input image data into image data expressed in a color space independent of the input source;
And second color conversion means for converting the image data converted by the first color conversion means into image data expressed in a color space composed of a developer color used by the first printing means. And
The first evaluation unit, when at least a part of the image data converted by the second color conversion unit deviates from the first color gamut, the number of pixels of the deviated image data and the deviation The distance between the pixel of the image data and the first color gamut that are out of the first color gamut is evaluated based on the distance from each pixel of the image data to the outline of the first color gamut. Image forming apparatus. When the first evaluation means drops a perpendicular line on the outer surface of the first color gamut from the image data out of the first color gamut of the image to be printed as the first evaluation value A value obtained by multiplying the length of the vertical line by the number of pixels of the deviated image data,
The second evaluation means uses the length of the perpendicular image data as the second evaluation value to the length of the perpendicular line when the perpendicular line is drawn on the contour surface of the second color gamut from the outlier image data. The image forming apparatus according to claim 4, wherein a value obtained by multiplying the number of pixels is obtained. The first evaluation means sets a value obtained by multiplying the first evaluation value by a preset weight value as a final first evaluation value,
The image forming apparatus according to claim 4, wherein the second evaluation unit uses a value obtained by multiplying the second evaluation value by the weighting value as a final second evaluation value. First calculation means for calculating costs for a plurality of developers used by the first printing means to print an image;
Second calculating means for calculating costs for a plurality of developers used by the second printing means for printing an image;
The first printing unit uses the determination result by the first determination unit, the determination result by the second determination unit, the calculation result by the first calculation unit, and the calculation result by the second calculation unit. The image forming apparatus according to claim 1, further comprising a selection unit that prompts selection of whether to print or to print by the second printing unit. In an image forming apparatus including a computer,
A first printing step for printing an image using a plurality of color developers;
A second printing step of printing an image using a plurality of color developers including a color different from the color of the developer used in the first printing step;
When image data of at least a part of an image to be printed is out of the first color gamut that can be reproduced by the first printing step, the number of pixels of the out-of-image data and the out-of-image data pixels A first evaluation step for evaluating a distance between a pixel of the deviated image data and the first color gamut based on a distance from each to a contour of the first color gamut;
A first determination step for determining which of the first printing step and the second printing step to perform printing;
Of the image to be printed, the number of pixels of the image data out of the first color gamut and the pixels of the image data out of the first color gamut to the outline of the second color gamut that can be printed by the second printing step. A second evaluation step for evaluating a separation between each pixel of the deviated image data and the second color gamut based on the distance;
A program that causes the computer to execute a second determination step of determining whether to perform printing by either the first printing step or the second printing step based on the evaluation by the second evaluation step .

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