JP2011029884A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for reducing color difference of a replicated medium between generations even when generation copy is repeatedly performed. <P>SOLUTION: The image forming apparatus includes: an image reading unit for reading a medium; an additional information extraction unit for extracting additional information from image data; a color reproduction method selection unit for determining whether a medium read from the additional information by the image reading unit is an original one or a replicated one, and selecting a generation copy color reproduction method when the determination result is a replicated one; a color reproduction unit for faithfully reproducing color information of the image data and achieving the generation copy color reproduction method for color-converting color information of a color gamut inexpressible in printing to information of a color gamut expressible in printing; an additional information generation unit for generating additional information of being a replicated medium; a print data generation unit for generating print data including both image data including color information after generation copy color reproduction processing and the additional information generated by the additional information generation unit; and a print unit for printing the print data. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including an image reading unit that reads a medium such as paper and converts it into image data, and a printing unit that prints print data on a medium such as paper.

2. Description of the Related Art Conventionally, an image forming apparatus realized by a multifunction device or the like reads an original document (original medium) with a scanner function using an RGB sensor and converts it into image data, and prints the color (input color) of image data having a wide color gamut The input color gamut is compressed within the output color reproduction range in order to make it within the output color reproduction range that can be expressed when the function prints. Then, the image forming apparatus outputs a copy (duplication medium) in which image data of color data in which the color gamut is compressed is printed. Therefore, a color difference occurs between the color of the duplicate medium and the color of the original medium.
The conventional image forming apparatus further reads the copy medium (first generation copy medium) with the scanner function, and prints the image data of the color data in which the color gamut of the input color is compressed within the output color reproduction range. A copy (second generation duplication medium) was output. For this reason, the color difference between the second-generation duplication medium and the original medium is wider than that of the first-generation duplication medium.
In this way, by repeating the generation copy in which the copy is further superimposed on the copy of the copy medium, the Nth generation copy medium in which the generation copy is repeated not only widens the color difference from the original medium, but also the first generation and the first copy. The color difference with the 2nd generation duplication media was also widening.

The image forming apparatus disclosed in Patent Document 1 embeds characteristics (feature amount information) of color data in a wide color gamut included in image data when the original medium is read by the scanner function. Then, as in the conventional method described above, the image forming apparatus reads the original medium with the scanner function to convert it into image data, and can output the input color of the image data having a wide color gamut when the printing function prints. In order to make it within the color reproduction range, the color gamut of the input color is compressed within the output color reproduction range. Then, the image forming apparatus outputs a copy (first generation duplication medium) in which the feature amount information is embedded in the image data of the compressed color data and printed.
The image forming apparatus disclosed in Patent Document 1 reads out the first generation copy medium with a scanner function to extract feature amount information embedded in the image data of the first generation copy medium, and extracts the extracted feature amount information ( Based on the original feature amount information), color correction is performed so that the color data obtained by reading the first generation copy medium is close to the color of the original medium having a wide color gamut.
Then, the image forming apparatus disclosed in Patent Document 1 sets the color gamut of the input color after color correction to the output color so that the input color after color correction falls within the output color reproduction range that can be expressed when the printing function prints. Compress within the reproduction range. Then, the image forming apparatus outputs a copy (second generation copy medium) in which the original feature amount information is embedded in the image data of the color data in which the color gamut is compressed.
As a result, the image forming apparatus disclosed in Patent Document 1 has almost no color difference between the color difference between the first generation duplication medium and the original medium and the color difference between the Nth generation duplication medium and the original medium in which generation copying is repeated. Unchanged generation copy can be made.

JP 2007-194850 A

  However, the image forming apparatus that embeds the original feature amount information in the image data performs color correction that approximates the color of the original medium, and thus reduces the spread of the color difference from the original medium every time generation copying is repeated. However, every time generational copying is performed, color correction is performed using characteristics (feature information) of color data in a wide color gamut included in the image data of the original medium, and the color gamut of the input color after color correction. Is performed within the output color reproduction range, so that there is a problem that the colors of the first generation, second generation,... .

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing the color difference of a copy medium between generations even when generation copy is repeatedly performed.

  In order to solve the above-described problem, an image forming apparatus according to claim 1 of the present invention provides an image reading unit that reads a duplicate medium, and color information in a color gamut that can express color information of the read image data during printing. An image forming apparatus including a color reproduction unit for conversion and a printing unit for performing generation copy using the color-converted print data, wherein the color reproduction unit faithfully reproduces color information of image data acquired from the image reading unit. And a generation copy color reproduction system that realizes color conversion of color information of a color gamut that cannot be expressed at the time of printing into color gamut information that can be expressed at the time of printing.

  According to the image forming apparatus of the present invention, color information of a color gamut that can be expressed at the time of printing of image data read from a duplicate medium is faithfully reproduced even at the time of printing, even if the medium has been subjected to repeated generation copying. Since the color information of the color gamut that cannot be expressed is color-converted into the information of the color gamut that can be expressed at the time of printing, the color difference of the replication medium between generations can be reduced.

1 is a block diagram of an image forming apparatus according to a first embodiment. FIG. 10 is a color tone diagram illustrating an outline of processing performed by an L ^* -C ^* two-dimensional coordinate plane and generation copy color reproduction processing X; FIG. 10 is a color diagram showing an outline of processing performed by an L ^* -C ^* two-dimensional coordinate plane and original color reproduction processing Y. 3 is a flowchart of processing operations performed by the image forming apparatus according to the first embodiment. 3 is a flowchart of processing operations performed by the image forming apparatus according to the first embodiment. FIG. 6 is a block diagram of an image forming apparatus according to a second embodiment. 10 is a flowchart of processing operations performed by an image forming apparatus according to a second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate, taking as an example the case where the present invention is applied to a digital multi-function peripheral having a scanner function and a copy function.
First, an image forming apparatus according to a first embodiment of the present invention will be described. FIG. 1 is a block diagram of an image forming apparatus according to the first embodiment of the present invention.

[Configuration of Image Forming Apparatus 1]
As shown in FIG. 1, the image forming apparatus 1 according to the first exemplary embodiment of the present invention includes an image data correction unit 10 and a scanner function to read a document to generate image data, and the image data correction unit 10. The image reading unit 30 for outputting to the printer and the printing unit 40 having a copy function and printing the print data acquired from the image data correction unit 10 are mainly provided.

[Configuration of Image Data Correction Unit 10]
The image data correction unit 10 acquires image data generated by the image reading unit 30 reading the medium, corrects the color of the image data, embeds additional information, and print data in a format printable by the printing unit 40. The generating unit includes an additional information extraction unit 11, a color reproduction method selection unit 12, an image correction unit 13, a color reproduction unit 14, an additional information generation unit 15, a print data generation unit 16, and a storage unit. 20.

The storage unit 20 stores input color reproduction range information 201 in which all the color information [L ^* , a ^* , b ^* ] that can be expressed in the CIELab (CIE 1976 L ^* a ^* b ^* color space) color system is stored. Output color reproduction range information 202 in which all the color information [L ^* , a ^* , b ^* ] (output color information) of the CIELab color system that can be expressed at the time of printing by the printing unit 40 is stored. It is a component that stores color conversion information 203.
The output color reproduction range information 202 is printed by the printing unit 40 by expressing colors in the CMYK color model (hereinafter referred to as CMYK) at the time of printing. Therefore, the CIELab color system color information that can be expressed in CMYK [ L ^* , a ^* , b ^* ].

The additional information extraction unit 11 is a component that extracts additional information included in image data generated by the image reading unit 30 reading a medium.
Here, the additional information may be an identification mark, a per-code, a two-dimensional code, or a digital watermark. If the original read by the image reading unit 30 is a duplicate, It is only necessary that the added additional information includes information (duplication information) indicating that the document has been duplicated.

The color reproduction method selection unit 12 determines whether or not duplicate information is included in the additional information extracted by the additional information extraction unit 11. This determination process is performed based on whether or not the duplicate information has been acquired from the additional information. As a result of the determination process, if copy information can be acquired, selection information including information indicating “generation copy” is generated. On the other hand, if copy information cannot be acquired, information indicating “original” is included. Generated selection information. Then, the selection information is output to the color reproduction unit 14.
Here, “original” indicates that the document read by the image reading unit 30 has never been copied. “Generation copy” indicates that the document read by the image reading unit 30 has been copied one or more times.

[Image Correction Unit 13]
The image correction unit 13 is a component that acquires the image data generated by the image reading unit 30 and performs image correction processing. For example, the image correction unit 13 performs image correction processing such as shading correction, filter processing, and descreening processing. The image correction unit 13 includes an input color component conversion unit 131.

The input color component conversion unit 131 is a configuration unit that converts color data represented by RGB signals included in image data into color information of the CIELab color system (L ^* a ^* b ^* color system).
For example, the color data [R, G, B] is first converted into the XYZ color system, and then further converted into the CIELab color system, whereby the lightness L that is the color information of the corresponding CIELab color system. ^* And chromaticity a ^* , b ^* can be converted. This conversion process is performed by performing a matrix operation.
Then, the input color component conversion unit 131 converts the color data [R, G, B] of all pixels constituting the image data into color information [L ^* , a ^* , b ^* ] of the CIELab color system. .

[Color reproduction unit 14]
The color reproduction unit 14 acquires the image data after the image correction processing and the processing performed by the input color component conversion unit 131 from the image correction unit 13, and the color information [L ^* , a of each pixel constituting the image data. ^* , B ^* ] (input color information) is acquired. Further, selection information is acquired from the color reproduction method selection unit 12. Then, in accordance with the selection information, generation color reproduction processing X or original color reproduction processing Y, which will be described later, is executed on the color information (input color information) of all the pixels constituting the image data, and the input color information Is converted into color information (output color information) of the CIELab color system that can be expressed by the printing unit 40 based on the output color reproduction range information 202 stored in the storage unit 20. This is a component that outputs the color-corrected image data that has been converted to the output color information (color correction) to the print data generator 16.

<Color conversion information 203>
The color conversion information 203 for conversion into output color information (correcting the color) performed by the color reproduction unit 14 is calculated in advance as shown below and stored in the storage unit 20.
The saturation C ^* of the color information [L ^* , a ^* , b ^* ] of the CIELab color system is calculated using Expression (1).

Here, FIG. 2 is a color tone diagram showing an outline of the processing performed by the L ^* -C ^* two-dimensional coordinate plane and the generation copy color reproduction processing X. FIG. 3 is a color diagram showing an outline of processing performed by the L ^* -C ^* two-dimensional coordinate plane and the original color reproduction processing Y.
Input color reproduction region F _in is an area of color tone based on the input color reproduction range information 201 stored in the storage unit 20. That is, this is an area where all of the color information [L ^* , a ^* , b ^* ] that can be expressed in the CIELab color system is expressed on the L ^* -C ^* two-dimensional coordinate plane.
The output color reproduction region F _out is a color tone region based on the output color reproduction range information 202 stored in the storage unit 20. That is, an area in which all the color information [L ^* , a ^* , b ^* ] (output color information) of the CIELab color system that can be expressed by the printing unit 40 during printing is expressed on the L ^* -C ^* two-dimensional coordinate plane. It is.
Region of color tone, towards the output color reproduction area F _out is what narrower than the input color reproduction region F _in.

Here, the point of the input color reproduction area F _in the P _in, the coordinates indicating the color of the point with ^{_{(L * in, C * in}} ). Moreover, the point of output color reproduction area F _out and P _out, the coordinates indicating the color of the point with ^{_{(L * out, C * out}} ).
A point T is a point where the saturation C ^* of the output color reproduction region _Fout becomes the maximum value, and the coordinates of the point T are indicated by (L ^* t, C ^* t). The point T ₀ is a point where the saturation C ^* of the color information of the point T is 0, and the coordinates of the point T ₀ are indicated by (L ^* t, 0).
Here, a straight line α passing through the coordinates (L ^* B _in , C ^* B _in ) of the point PB _in on the boundary line (Borderline) of the input color reproduction area F _in and the point T ₀ , and the output color reproduction area F _out the coordinates of a is point PB _out intersection of the boundary line represented by ^{_{(L * B out, C *}} B out).
Based on these coordinates, from a distance DBv the point PB _in the point PB _out, and calculates the distance DBW the point PB _in the point T _0, and a distance DBv and distance DBW, scale ratio r (= DBv / DBw) is calculated.

As shown above,
・ Point T coordinates (color tone)
・ Coordinates of point T ₀ (color tone)
• Input color reproduction area F _in the point PB _in the boundary line (point PB _in1, point PB _in2, ···) all of the coordinates of the (color)
- point PB _in number (point PB _in1, point PB _in2, · · ·) exists only linear alpha (alpha ₁ passing through the PB _in the point T ₀ point on the boundary line of the input color reproduction area F _in, alpha ₂ , ...)
- linear _{α (α 1, α 2,} ···) , the output color reproduction region F _out intersection PB _out of the boundary line (point PB _out1, point PB _out2, · · ·) of the coordinates (color)
-Scale ratio r exists as many as the number of straight lines α
Such information is stored as color conversion information 203 in the storage unit 20 in association with a database (not shown).
The scale ratio r corresponds to the point PB _in (point PB _in1 , point PB _in2 ,...) And point PB _out (point PB _out1 , point PB _out2 ) on the straight line α (α ₁ , α ₂ ,...). ,...) And are stored in association with each other.

<Generation copy color reproduction process X>
The generation copy color reproduction process X executed by the color reproduction unit 14 will be described below.
When the selection information acquired from the color reproduction method selection unit 12 is “generation copy”, the color reproduction unit 14 executes generation copy color reproduction processing X. Thereby, when the input color information is color information within the output reproduction range (color information included in the output color reproduction range information 202) with reference to the output color reproduction range information 202 stored in the storage unit 20. A color that matches the input color information is set as output color information. On the other hand, if the input color information is output reproduction range of the color information (color information not included in the output color gamut in the information 202), closest to the hue of the point T _0, the input color information within the output gamut the tone color information is (borderline color output color reproduction area F _out) to output color information.

The color reproduction unit 14 executes the generation copy color reproduction process X, thereby converting the input color information into output color information as shown below.
First, the color reproduction unit 14 acquires input color reproduction range information 201, output color reproduction range information 202, and color conversion information 203 from the storage unit 20.
Then, the color reproduction unit 14 calculates the saturation C ^* of the input color information (color information [L ^* , a ^* , b ^* ] of the CIELab color system) using the expression (1), whereby the input color The coordinates (L ^* _in , C ^* _in ) indicating the color tone of the information are acquired.

Separately, the hue angle h of the input color information [L ^* , a ^* , b ^* ] is calculated using Equation (2).

Next, the color reproduction unit 14 determines whether or not the coordinates (color tone) of the input color information are coordinates (color tone) within the output reproduction range, and the coordinates of the input color information are coordinates within the output reproduction range. In this case, the color that matches the input color information is set as the output color information.
On the other hand, if the input color information is color information of the outside output gamut, the boundary of the coordinate of the input color information ^{_{Pm in (L * m in,}} C * m in) is, which linear alpha (input color reproduction region F _in A straight line passing through the point PB _in and the point T ₀ on the line) is determined, and the corresponding (located) straight line is acquired.
The output color of the input color information Pm _in has a linear α _{^{extracted, (L * B out, C}} * B out) of the coordinates of the output color reproduction area F _out intersection at which point PB _out of the boundary line in Indicated.

以上のようにして、入力色情報が出力再現範囲外の色情報である場合、点Ｔ₀の色調に一番近く、出力再現範囲内の入力色情報の色調を有する出力色再現領域Ｆ_outの境界線上の色情報［Ｌ^*Ｂ_out，ａ^*Ｂ_out，ｂ^*Ｂ_out］が、出力色情報に選出される。 The output color information ^{_{[L * B out, a *}} B out, b * B out] in the ^{_{a * B out, b * B}} out using Formula (3) can be calculated.

As described above, when the input color information is color information of the outside output gamut, near best color tone of the point T _0, the output color reproduction region F _out with the color tone of the input color information within the output gamut Color information [L ^* B _out , a ^* B _out , b ^* B _out ] on the boundary line is selected as output color information.

<Original color reproduction process Y>
The original color reproduction process Y executed by the color reproduction unit 14 will be described below.
When the selection information acquired from the color reproduction method selection unit 12 is “original”, the color reproduction unit 14 executes the original color reproduction process Y. Thereby, the input color information is converted into output color information within the output reproduction range.

FIG as shown in 3, the color reproducing unit 14 original color reproduction process Y, the input located on the straight line α passing through the input color reproduction region F _in the point T ₀ and the point (point PB _in) on the boundary line of the color From the coordinates (L ^* n _in , C ^* n _in ) of (point Pn _in ), the coordinates of the output color (point Pn _out ) are calculated as follows.

First, the color reproduction unit 14 acquires input color reproduction range information 201, output color reproduction range information 202, and color conversion information 203 from the storage unit 20.
Then, the distance Dnw between the point Pn _in and the point T ₀ is obtained, the distance Dnw and the scale ratio r are multiplied to calculate the distance Dnv, and the position moved from the point Pn _in the direction of the point T _{0 by} the distance Dnv Coordinates (L ^* n _out , C ^* n _out ) are coordinates of the output color (point Pn _out ).

そして、色再現部１４は、得られた点Ｐｎ_outの座標（Ｌ^*ｎ_out，Ｃ^*ｎ_out）から、出力色の色情報［Ｌ^*ｎ_out，ａ^*ｎ_out，ｂ^*ｎ_out］を算出する。同様に、出力色情報［Ｌ^*Ｂ_out，ａ^*Ｂ_out，ｂ^*Ｂ_out］のａ^*Ｂ_out、ｂ^*Ｂ_outは、式（３）により、算出することができる。 Here, the procedure for calculating the coordinates of the output color (point Pn _out ) is represented by a formula (4).

Then, the color reproducing unit 14, the resulting points Pn _out of the coordinates ^{_{(L * n out, C *}} n out) from the color information of the output color ^{_{[L * n out, a *}} n out, b * n out] Is calculated. Similarly, the output color information ^{_{[L * B out, a *}} B out, b * B out] in the ^{_{a * B out, b * B}} out using Formula (3) can be calculated.

  The color reproduction unit 14 prints color-corrected image data that has been converted to output color information (color correction) and is obtained by executing the generation copy color reproduction process X or the original color reproduction process Y described above. The data is output to the data generation unit 16.

[Additional information generation unit 15]
The additional information generation unit 15 is a component that generates additional information including duplication information and outputs the additional information to the print data generation unit 16.
The additional information generated here is information that the additional information extraction unit 11 can extract from the image data generated by the image reading unit 30.

[Print Data Generation Unit 16]
The print data generation unit 16 acquires color correction image data from the color reproduction unit 14, and outputs color components that are converted into CMYK color information expressed in the CIELab color system (L ^* a ^* b ^* color system). A conversion unit 161 is provided, which converts the color information of the color correction image data into CMYK and generates print data in which the additional information acquired from the additional information generation unit 15 is embedded.
Then, the print data generation unit 16 outputs the print data to the printing unit 40.

Here, the output color component conversion unit 161 responds, for example, by converting the color information [L ^* , a ^* , b ^* ] to the XYZ color system first, and then to CMYK. It can be converted into color data [C, M, Y, K] expressed in CMYK. This conversion process is performed by performing a matrix operation.

  The image forming apparatus 1 is configured by a general computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an HD (Hard Disc), and the like (not shown). And can be operated by a program that causes the computer to function as each of the means described above.

[Processing Operation of Image Forming Apparatus 1]
Next, processing operations performed by the image forming apparatus 1 according to the first embodiment of the present invention will be described with reference to FIGS. 4 and 5 (refer to FIGS. 1 to 3 as appropriate).
First, the image reading unit 30 reads a document, generates image data, and outputs the image data to the image data correction unit 10 (step S101, FIG. 4).

The image correction unit 13 performs image correction processing such as shading correction, filter processing, and descreening processing on the image data acquired from the image reading unit 30 (step S102).
The input color component conversion unit 131 converts the color data [R, G, B] represented by the RGB signals included in the image data subjected to the image correction processing into color information [L ^* , a ^* ] of the CIELab color system ^. , B ^* ] (RGB → CIELab) (step S103). Thereby, the color reproduction unit 14 acquires color information [L ^* , a ^* , b ^* ] (input color information) of each pixel constituting the image data from the input color component conversion unit 131 (step S104).

The additional information extraction unit 11 extracts additional information included in the image data acquired from the image reading unit 30 (step S105).
The color reproduction method selection unit 12 determines whether or not the duplicate information has been acquired from the additional information extracted by the additional information extraction unit 11 (step S106).
When duplication information has been acquired (step S106, Yes), the color reproduction method selection unit 12 generates selection information including information indicating “generation copy” (step S107). On the other hand, when the copy information cannot be acquired (No at Step S106), the color reproduction method selection unit 12 generates selection information including information indicating “original” (Step S108).
Then, the color reproduction method selection unit 12 outputs the generated selection information to the color reproduction unit 14 (step S109). Thereby, the color reproduction part 14 acquires selection information from the color reproduction system selection part 12 (step S110).

Then, the color reproduction unit 14 determines selection information (generation copy / original) (step S111, FIG. 5).
When the selection information is “generation copy” (step S111, generation copy), the color reproduction unit 14 executes generation copy color reproduction processing X (step S112), and the input color information is stored in the storage unit 20. Based on the output color reproduction range information 202, the printing unit 40 converts the information into CIELab color system color information (output color information) that can be expressed during printing (step S113).

On the other hand, when the selection information is “original” (step S111, original), the color reproduction unit 14 executes the original color reproduction process Y (step S114) and outputs the input color information stored in the storage unit 20 Based on the in-color reproduction range information 202, the printing unit 40 converts the color information (output color information) that can be expressed during printing (step S115).
The color reproduction unit 14 generates color corrected image data in which the color information (input color information) of all the pixels constituting the image data is converted into output color information (color correction) (step S116).
The additional information generation unit 15 generates additional information including duplicate information (step S117).

The print data generation unit 16 acquires the color correction image data from the color reproduction unit 14, and further acquires additional information from the additional information generation unit 15 (step S118).
The output color component conversion unit 161 converts the color information of the color-corrected image data expressed in the CIELab color system into CMYK color data (CIELab → CMYK) (step S119).
The print data generation unit 16 generates print data in which the additional information acquired from the additional information generation unit 15 is embedded (step S120). Then, the print data generation unit 16 outputs the print data to the printing unit 40 (step S121). Accordingly, the printing unit 40 starts a printing process for printing the print data on a predetermined medium. Then, the image forming apparatus 1 ends all the processes.

  According to the image forming apparatus 1 according to the first embodiment of the present invention, generation copy color reproduction processing that maintains a color within the output color reproduction range is selected during generation copy, so that color reproduction is performed during intergenerational copying. Improves.

<Second Embodiment>
Subsequently, an image forming apparatus according to a second embodiment of the present invention will be described. The description will focus on the differences from the image forming apparatus 1 according to the first embodiment. FIG. 6 is a block diagram of an image forming apparatus according to the second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

[Configuration of Image Forming Apparatus 1A and Image Data Correction Unit 10A]
As shown in FIG. 6, an image forming apparatus 1A according to the second embodiment of the present invention replaces the color reproduction method selection unit 12 included in the image data correction unit 10 according to the first embodiment of the present invention. A color reproduction method selection unit 12A is provided, and the image data correction unit 10A further includes an input color region detection unit 17. Further, in addition to the configuration of the image forming apparatus 1 according to the first embodiment of the present invention, instruction data that is operated by the user and includes instruction contents input by the user is generated and output to the color reproduction method selection unit 12A. An input unit 50 and a display unit 60 that generates and outputs display image data visible to the user.

[Color reproduction method selection unit 12A]
The color reproduction method selection unit 12A determines whether or not the duplicate information is included in the additional information extracted by the additional information extraction unit 11 based on whether or not the duplicate information can be acquired from the additional information. In response to this, detection request data is output to the input color region detection unit 17, return data is acquired from the input color region detection unit 17, or instruction data is acquired from the input unit 50. The selection unit generates selection information including information indicating “generation copy” or “original” according to the determination result and data from the external configuration unit, and outputs the selection information to the color reproduction unit 14.
For example, the color reproduction method selection unit 12A performs the following processing.

The color reproduction method selection unit 12A determines whether or not the additional information extracted by the additional information extraction unit 11 includes duplicate information. This determination process is performed based on whether or not the duplicate information has been acquired from the additional information.
As a result of the determination process, when the copy information cannot be acquired, the color reproduction method selection unit 12A generates selection information including information indicating “original” and outputs the selection information to the color reproduction unit 14. The processing when this duplication information cannot be acquired is the same as that of the color reproduction method selection unit 12 of the first embodiment.
On the other hand, if the copy information can be acquired as a result of the determination process, the color reproduction method selection unit 12A outputs detection request data that causes the input color region detection unit 17 to start processing, and then the input color region detection unit 17 The process waits until the return data is acquired from, or until the instruction data is acquired from the input unit 50.

When acquiring the return data from the input color area detection unit 17, the color reproduction method selection unit 12 A generates selection information including information indicating “generation copy” and outputs the selection information to the color reproduction unit 14. This process is the same as the process when the copy information of the color reproduction method selection unit 12 of the first embodiment can be acquired.
On the other hand, when the instruction data is acquired from the input unit 50, the color reproduction method selection unit 12A includes information indicating “generation copy” if the information of the instruction data is information for selecting the generation copy color reproduction process X. On the other hand, if it is information for selecting the original color reproduction process Y, selection information including information indicating “original” is generated and output to the color reproduction unit 14 described later. The process for generating the selection information is the same as that of the color reproduction method selection unit 12 of the first embodiment.

[Input Color Area Detection Unit 17]
The input color area detection unit 17 starts the processing after obtaining the detection request data for starting the processing from the color reproduction method selection unit 12A, and outputs the output stored in the storage unit 20 for all the pixels constituting the image data. Referring to the color reproduction range information 202, the ratio of pixels having color information outside the output color reproduction range (color information not included in the output color reproduction range information 202) is calculated, and according to the calculated value The detection unit generates screen data that allows the user to select a process (generation copy color reproduction process X or original color reproduction process Y) to be executed by the color reproduction unit 14.
For example, the input color region detection unit 17 performs the following processing.

First, the input color area detection unit 17 that has acquired the processing start detection request data from the color reproduction method selection unit 12A acquires the image data that the color reproduction unit 14 has acquired from the input color component conversion unit 131 from the color reproduction unit 14. To do. Here, the image data acquired by the input color area detection unit 17 is only required to convert the RGB color data included in the image data into color information of the CIELab color system, and the input color component conversion unit 131 directly. You may acquire image data from.
The color information [L ^* , a ^* , b ^* ] (input color information) of each pixel constituting the image data is acquired, and the color information outside the output color reproduction range is obtained for all the pixels constituting the image data. The ratio (ratio value R) occupied by the pixels having is calculated.

If the ratio value R is less than the predetermined value K, the input color region detection unit 17 causes the color reproduction method selection unit 12A to generate selection information including information indicating “generation copy”. Return data is output to the selection unit 12A.
On the other hand, if the ratio value R is equal to or greater than the predetermined value K, the input color area detection unit 17 allows the user to select a process to be executed by the color reproduction unit 14, a generation copy color reproduction process X, or an original color reproduction process Y. And outputs screen data to the display unit 60.

Here, the predetermined value K is a predetermined value, and by setting the predetermined value K to a small value, the rate of generating screen data that can be selected by the user increases, and the color reproduction method provided in the image forming apparatus 1A. Since the selection unit 12A, the input color region detection unit 17, the input unit 50, and the display unit 60 can cause the user to select a process to be executed by the color reproduction unit 14, the color reproduction process intended by the user can be performed. It can be carried out.
The predetermined value K may be information included in the input color area detection unit 17 or may be information stored in the storage unit 20.

[Processing Operation of Image Forming Apparatus 1A]
Subsequently, processing performed by the image forming apparatus 1A according to the second exemplary embodiment of the present invention will be described with reference to FIG. 7 (refer to FIGS. 4 and 6 as appropriate). Here, the description of the processes (steps S101 to S105 and steps S109 to S121) that are the same as the processes performed by the image forming apparatus 1 according to the first embodiment described in FIGS.

The additional information extraction unit 11 extracts additional information included in the image data acquired from the image reading unit 30 (step S105, FIG. 4).
The color reproduction method selection unit 12A determines whether or not the duplicate information has been acquired from the additional information extracted by the additional information extraction unit 11 (step S201).
When the duplicate information cannot be acquired (No at Step S201), the color reproduction method selection unit 12A generates selection information including information indicating “original” (Step S202). Then, the color reproduction method selection unit 12A outputs the generated selection information to the color reproduction unit 14 (step S109, FIG. 4).
On the other hand, when the duplicate information can be acquired (step S201, Yes), the color reproduction method selection unit 12A generates detection request data and outputs the detection request data to the input color region detection unit 17 (step S203).

In step S104 (FIG. 4), the input color region detection unit 17 performs color information [L ^* , a ^* , b ^{* of} each pixel constituting the image data acquired by the color reproduction unit 14 from the input color component conversion unit 131 ^. ] (Input color information) is acquired from the color reproduction unit 14 (step S204).
Then, the input color region detection unit 17 refers to the output color reproduction range information 202 stored in the storage unit 20 for all the pixels constituting the image data, and the color information that is outside the output color reproduction range. The ratio value R occupied by the pixels having is calculated (step S205), and the ratio value R is compared with the predetermined value K (step S206).

  If the ratio value R is less than the predetermined value K (step S206, R <K), the input color region detection unit 17 outputs return data to the color reproduction method selection unit 12A (step S207). Then, the color reproduction method selection unit 12A generates selection information including information indicating “generation copy” (step S208). Then, the generated selection information is output to the color reproduction unit 14 (step S109, FIG. 4).

On the other hand, if the ratio value R is equal to or greater than the predetermined value K (step S206, R ≧ K), the input color area detection unit 17 performs the generation copy color reproduction process X or the original color reproduction that is a process to be executed by the color reproduction unit 14. Screen data that allows the user to select the process Y is generated (step S209) and output to the display unit 60.
The display unit 60 acquires screen data from the input color area detection unit 17 and displays a screen that the user can view (step S210). The input unit 50 converts the instruction input by the user (step S211) into data. The instruction data is output to the color reproduction method selection unit 12A.

The color reproduction method selection unit 12A determines information included in the instruction data (step S212).
If the instruction data is information that the generation copy color reproduction process X is selected (step S212, generation copy color reproduction process X), the color reproduction method selection unit 12A generates selection information including information indicating “generation copy”. (Step S213).
On the other hand, if the instruction data is information indicating that the original color reproduction process Y is selected (step S212, original color reproduction process Y), the color reproduction method selection unit 12A generates selection information including information indicating “original”. (Step S214).
Then, the generated selection information is output to the color reproduction unit 14 (step S109, FIG. 4).

  According to the image forming apparatus 1A according to the second embodiment of the present invention, the user's intention is obtained by selecting a color reproduction method in accordance with a user instruction in a copy that is a copy original by adding new information to the copy output. Color reproduction processing can be performed.

In the embodiment, an example in which a digital multifunction peripheral is applied as an image forming apparatus has been described. However, the present invention can also be applied to a facsimile (FAX) or a copier. Needless to say, the present invention can be applied not only to an electrophotographic system but also to an image forming apparatus such as an inkjet.
Further, as additional information, an identification mark may be added and detection by pattern matching may be used, or addition and detection of information using a barcode or a two-dimensional code, or addition and detection of information by digital watermarking You may go.
In the embodiment, the mapping method from the input color reproduction range to the output color reproduction range in the color reproduction processing has been described using mapping based on a point on the achromatic color axis (L ^* axis). However, the present invention is not limited to this. Instead, various mapping methods for mapping the tone within the input color reproduction range to the output color reproduction range can be applied.

  Further, in the embodiment, the color conversion information 203 for converting into the output color information (correcting the color) performed by the color reproduction unit 14 is calculated in advance and stored in the storage unit 20. This is because the processing speed until printing is taken into consideration. Therefore, the configuration may be such that information such as all values and expressions stored in the storage unit 20 as the color conversion information 203 is sequentially calculated or extracted.

In the embodiment, the input color component conversion unit 131 converts the color data represented by the RGB signal included in the image data into color information of the CIELab color system. However, the CIE uv color system (CIE 1976). L ^* u ^* v ^* color space) color information may be converted.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image data correction part 11 Additional information extraction part 12 Color reproduction system selection part 13 Image correction part 14 Color reproduction part 15 Additional information generation part 16 Print data generation part 20 Storage part 30 Image reading part (RGB signal)
40 Printing unit 50 Input unit 60 Display unit 131 Input color component conversion unit (CIELab conversion)
161 Output color component converter (CMYK conversion)
201 Input color reproduction range information 202 Output color reproduction range information 203 Color conversion information X generation copy color reproduction processing Y Original color reproduction processing

Claims (5)

An image reading unit that reads a copy medium, a color reproduction unit that converts color information of the read image data into information of a color gamut that can be expressed at the time of printing, and a printing unit that performs generation copy with the color-converted print data An image forming apparatus comprising:
The color reproduction unit faithfully reproduces the color information of the image data acquired from the image reading unit, and color-converts color information of a color gamut that cannot be expressed at the time of printing into information on a color gamut that can be expressed at the time of printing. An image forming apparatus that performs generation copy color reproduction processing. An additional information extraction unit that acquires the image data from the image reading unit and extracts additional information from the image data;
It is determined from the additional information whether the medium read by the image reading unit is an original medium or the duplicate medium, and the color reproduction unit obtains from the image reading unit when the determination result is the original medium. Select an original color reproduction method that uniformly converts all gamut information contained in the image data into gamut information that can be expressed at the time of printing. A color reproduction method selection unit for selecting a method;
An additional information generating unit that generates the additional information indicating that the medium is a duplicate medium;
Image data including color information after performing the original color reproduction process for realizing the original color reproduction method or the generation copy color reproduction process for realizing the generation copy color reproduction method, and the additional information generation unit A print data generation unit that generates print data including both additional information and
The image forming apparatus according to claim 1, wherein the printing unit prints the print data. The generation copy color reproduction process is
Both the color information in the input color reproduction range that is the range of color information that can be read by the image reading unit and the color information in the output color reproduction range that is the range of color information that can be expressed by the printing unit during printing. Is expressed by the color tone indicated by the brightness value and the saturation value,
If the color tone of the image data read by the image reading unit is within the output color reproduction range, the color information in the output color reproduction range is used,
If the color tone of the image data read by the image reading unit is a color tone outside the output color reproduction range, the lightness value at the highest saturation value and the zero saturation value in the color tone within the output color reproduction range, The image forming apparatus according to claim 2, wherein the image forming apparatus converts the color tone closest to the color tone expressed by the color tone within the output color reproduction range.   The image forming apparatus according to claim 3, wherein the saturation value and the brightness value are calculated by converting image data read by the image reading unit into a CIELab color system. Obtaining color information of the image data from the color reproduction unit, calculating a ratio value occupied by pixels having color information outside the output color reproduction range for all pixels constituting the image data, and calculating the ratio value If the ratio value is less than a predetermined value, the color tone conversion data is output to the color reproduction method selection unit. On the other hand, if the ratio value is equal to or greater than the predetermined value, the original color reproduction method or the generation copy color reproduction method. An input color area detection unit that generates screen data for selecting
A display unit for outputting the screen data so as to be visible to the user;
An input unit that generates instruction data based on the user's operation,
The color reproduction method selection unit
When the determination result is a duplication medium, output detection request data that causes the input color area detection unit to start processing,
By obtaining the conversion data from the input color area detection unit, select a generation copy color reproduction method,
By obtaining the instruction data from the input unit, the instruction data is determined, and if the instruction data is the selection of the original color reproduction method, the original color reproduction method is selected, and the instruction data is the generation 5. The image forming apparatus according to claim 3, wherein if the copy color reproduction method is selected, a generation copy color reproduction method is selected.

Images