JP4882339B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a technique for forming an image that more faithfully reproduces the color of an object to be imaged.

  In general scanners and copiers used in offices and the like, it is often difficult to read fluorescent colors. For example, when a document marked with a highlighter is copied, an area that should originally be a fluorescent color is usually reproduced with a color (low saturation) that is different from the actual color. This is because light received when a document including a fluorescent material is irradiated with light is emitted when the fluorescent material transitions from an excited state to a ground state in addition to reflected light from the surface of the document (fluorescence). Is included.

As a technique for reproducing a fluorescent color included in an original, for example, there is a technique described in Patent Document 1. The technique described in Patent Document 1 recognizes an image area including a fluorescent color material by irradiating an original with ultraviolet light, and reproduces the image area using fluorescent toner.
JP-A-10-107970

However, when the technique described in Patent Document 1 is used, there is a high possibility that so-called metamerism (conditional color) occurs. That is, an image (a copy) formed using the above-described technique may match the original well under a specific light source, but will have a different color from the original when the light source conditions are different. Become visible. When metamerism occurs in this way, the colors of the original and the copy only match under specific conditions, so it cannot be said that color reproduction faithfully follows the original.
In addition, although there is a method for measuring the fluorescent color more strictly, complicated measurement and calculation are required, and in order to realize this, it is inevitable to increase the size and cost of the apparatus. Therefore, it is not realistic to apply this method for general purposes used in offices and the like.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to read a captured object using a simple configuration and obtain a copy that more faithfully reproduces the color of the captured object. It is to provide a technology that makes it possible.

In order to achieve the above-described object, an image forming apparatus according to the present invention includes an irradiation unit that irradiates an object to be picked up with light having a spectral energy distribution over at least the entire visible region, the light reflected by out the object to be imaged and received by a plurality of different spectral sensitivity, a light receiving means for generating image data representing the color of the object to be imaged on the basis of these received light generated by the light receiving means Discrimination means for discriminating an image area indicating a color included in the determined color area, and image forming means for forming an image according to the image data generated by the light receiving means on the sheet. Te, the relative its color by determining means image area is determined to be included in the color area, a plurality of coloring materials for forming an image of a color contained in the color region by the combination preparation Using a color material, relative to the other image area, and an image forming means for forming an image by using at least a certain color material is a color material capable of forming an image of a color not included in the color area. In the present invention, it is desirable that the light receiving means has a plurality of light receiving element rows of at least four rows, and each light receiving device row has a different spectral sensitivity. According to this image forming apparatus, it is possible to estimate the spectral reflectance of the object to be imaged and to secure a wider color reproduction range.

  In the present invention, the image forming unit may display an image indicating a color whose difference from a color not included in the color area is equal to or lower than a predetermined level among colors included in the color area. And the specific color material. In this way, a more natural image can be formed.

  In the present invention, it is preferable that the image forming unit is an electrophotographic image forming unit having a plurality of rotary developing units. With such a configuration, it is possible to increase the number of colors used while suppressing an increase in size of the apparatus. In this case, it is more preferable that the standard color material includes cyan, magenta, yellow, and black toners, and the specific color material includes fluorescent toner.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, an electrophotographic copying machine will be described as an embodiment of the present invention. Note that, in the present embodiment, due to the configuration, an object to be imaged as an image reading target is assumed to be mainly a sheet-like object such as paper or a metal plate. However, the reading target in the present invention is not limited to such an object.

[1. Constitution]
FIG. 1 is a block diagram schematically showing a configuration of a copying machine 100 according to an embodiment of the present invention. FIG. 2 is a diagram more specifically showing the configuration of the image reading unit 10 and the image forming unit 20 of the copying machine 100. First, the configuration of the image reading unit 10 and the image forming unit 20 will be described in detail.

  The image reading unit 10 has a so-called image scanner function, and the image forming unit 20 has a so-called printer function. Among these, the image reading unit 10 includes a platen glass 11, a platen cover 12, a full rate carriage 13, a half rate carriage 14, an imaging lens 15, and a line sensor 16.

  The platen glass 11 is a transparent glass plate on which the object to be imaged O to be read is placed. The platen glass 11 is installed so that the surface thereof is horizontal. Further, a reflection suppressing layer such as a multilayer dielectric film is formed on the surface of the platen glass 11 so that reflection on the surface of the platen glass 11 is reduced. This is to prevent the reflected light component from the surface of the object to be imaged O, which should be read originally, and the reflected light component from the surface of the platen glass 11, which is an unnecessary component, from being read in a combined state. For the purpose of separating the reflected light component from the object to be imaged O and the reflected light component from the surface of the platen glass 11, for example, by providing a spacer, the surface of the object to be imaged O and the surface of the platen glass 11 are separated by a predetermined distance. You may make it isolate | separate only.

The platen cover 12 is provided so as to cover the platen glass 11 and blocks the external light to facilitate reading of the object to be imaged O placed on the platen glass 11. The full rate carriage 13 includes a light source 131 and a mirror 132. The light source 131 is a single light source whose spectral energy distribution covers at least the entire visible region, and is, for example, a tungsten halogen lamp or a xenon arc lamp. The light source 131 irradiates the object to be imaged O with light having a predetermined intensity at an incident angle of about 45 °. The spectral energy distribution of the light source 131 preferably includes the ultraviolet region as much as natural light. In this way, accurate reading can be performed even when the excitation wavelength of the fluorescent material is included in the ultraviolet region.

  The mirror 132 further reflects the reflected light from the object to be imaged O and forms an optical path (one-dot chain line in the figure) for guiding this light to the half-rate carriage 14. Note that light incident on the mirror 132 is light reflected at a reflection angle of approximately 0 ° with respect to the reflection surface of the object to be imaged O, and most of the light is a diffuse reflection component. The full-rate carriage 13 moves in the direction of arrow A or B in FIG. 2 during scanning, and scans the entire surface while irradiating the object to be imaged O with light.

  The half-rate carriage 14 includes mirrors 141 and 142 and forms an optical path that guides light from the full-rate carriage 13 to the imaging lens 15. The half-rate carriage 14 is driven by a drive mechanism (not shown), and is moved in the same direction as the full-rate carriage 13 at a half speed of the full-rate carriage 13 during scanning.

  The imaging lens 15 is provided on an optical path connecting the mirror 142 and the line sensor 16, and images light from the object to be imaged O at the position of the line sensor 16. The line sensor 16 is, for example, a multi-line CCD image sensor (light receiving element array) provided with an on-chip color filter. This CCD image sensor images an object to be picked up with different spectral sensitivities for each line, and generates an image signal. In the present embodiment, a CCD image sensor having peaks in the wavelength regions of four colors B (blue), BG (blue green), G (green), and R (red) is used.

  Next, the configuration of the image forming unit 20 will be described. The image forming unit 20 includes a plurality of paper feed trays 21, a plurality of transport rolls 22, primary transfer units 23 a, 23 b and 23 c, an intermediate transfer belt 24, a secondary transfer roll 25, a backup roll 26, and a primary roll. A fixing mechanism 27, a switching mechanism 28, and a secondary fixing mechanism 29 are provided.

  Each of the sheet feeding trays 21 stores a sheet of a predetermined size and supplies the sheet in accordance with image formation. Here, the sheet is a sheet normally used in image formation such as a so-called PPC (Plain Paper Copier) sheet, but if necessary, a sheet of a material other than paper or paper whose surface is coated with resin or the like is used. It can also be used. The transport roll 22 forms a transport path for transporting the sheet supplied from the paper feed tray 21 to a position where the secondary transfer roll 25 and the backup roll 26 face each other. The sheet conveyance path is a path indicated by a broken line in FIG. The primary transfer units 23a, 23b, and 23c form toner images according to the supplied image data, and transfer the formed toner images to the intermediate transfer belt 24.

  Here, the configuration of the primary transfer units 23a, 23b, and 23c will be described in more detail with reference to FIG. The primary transfer units 23a, 23b, and 23c differ only in the toner used, and the respective configurations are the same. Therefore, here, the reference numerals a, b, and c attached to each component are omitted.

  The primary transfer unit 23 includes a photosensitive drum 231, a charger 232, an exposure unit 233, development units 234, 235, 236 and 237, and a primary transfer roll 238. The photosensitive drum 231 is an image carrier having a photoconductive layer made of OPC (Organic Photo Conductor) as a charge acceptor formed on the surface thereof, and is rotated in the direction of arrow C in the figure. The charger 232 includes a charging roller, and uniformly charges the surface of the photosensitive drum 231. The exposure device 233 irradiates the photosensitive drum 231 with light by a laser diode, and forms an electrostatic latent image with a predetermined potential on the surface thereof. The developing units 234, 235, 236, and 237 store toners of different colors and generate a predetermined potential difference (developing bias) between the surface of the photosensitive drum 231 and are formed on the surface of the photosensitive drum 231 by the potential difference. A toner image is formed by attaching toner to the electrostatic latent image thus formed. The developing units 234 to 237 constitute a so-called rotary type developing device. The primary transfer roll 238 generates a predetermined potential difference (primary transfer bias) at a position where the intermediate transfer belt 24 faces the photosensitive drum 231, and transfers the toner image onto the surface of the intermediate transfer belt 24 by this potential difference.

  The toners stored in the developing units 234, 235, 236, and 237 are four colors of cyan, magenta, yellow, and black, and four colors of red, orange, green, and blue (the above eight colors are referred to as “color toners”). )), Three colors of fluorescent cyan, fluorescent magenta, and fluorescent yellow (the above three colors are referred to as “fluorescent toner”) and a transparent toner (hereinafter referred to as “transparent toner”). Color.

Here, the transparent toner is a toner that does not contain a color material. For example, a low molecular weight polyester resin is externally added with SiO ₂ (silicon dioxide) or TiO ₂ (titanium dioxide). By forming a toner image with transparent toner on the entire image, the level difference due to the difference in toner amount at each position of the image is reduced, and the unevenness of the image surface becomes less noticeable.

  These toners are accommodated in appropriate positions in the primary transfer units 23a, 23b, and 23c depending on the frequency of use. However, fluorescent toner and transparent toner are transferred before other toners. It is desirable to be done. This is because the fluorescent toner and the transparent toner are transferred on the sheet surface so as to cover the other toners.

  Here, referring back to FIG. 2, the other components of the image forming unit 20 will be described. The intermediate transfer belt 24 is an endless belt member that is moved in the direction of arrow D in the drawing by a driving mechanism (not shown). The intermediate transfer belt 24 transfers (primary transfer) the toner image at a position facing the photosensitive drums 231a, 231b, and 231c, and moves the toner image to transfer (secondary transfer) to the sheet. The secondary transfer roll 25 and the backup roll 26 cause a predetermined potential difference (secondary transfer bias) at a position where the intermediate transfer belt 24 faces the sheet, and transfers the toner image onto the sheet. The primary fixing mechanism 27 includes a roll member for heating and pressurizing the sheet, and fixes the toner image transferred on the surface of the sheet. The switching mechanism 28 changes the sheet conveyance path according to the type of toner image formed on the surface of the sheet. Specifically, the switching mechanism 28 conveys a sheet whose toner image contains transparent toner in the direction of arrow R in the figure, and conveys and discharges other sheets in the direction of arrow L in the figure. Let

  The secondary fixing mechanism 29 includes a fixing belt 291, a heater 292, and a heat sink 293. The secondary fixing mechanism 29 further applies heat to the sheet once heated and pressure-fixed in the primary fixing mechanism 27 by the heater 292 to re-melt the toner. Then, the secondary fixing mechanism 29 cools the sheet with the heat sink 293 while keeping the sheet in close contact with the smooth fixing belt 291 and fixes the toner. By performing such a fixing process, a toner image with a smooth surface and high glossiness can be formed.

  The configurations of the image reading unit 10 and the image forming unit 20 are as described above. Next, another configuration of the copying machine 100 will be described with reference to the block diagram of FIG. The copying machine 100 includes a control unit 30, a storage unit 40, an image processing unit 50, an operation unit 60, and a communication unit 70 in addition to the image reading unit 10 and the image forming unit 20 described above.

  The control unit 30 is an arithmetic unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc. (not shown), and is copied by executing a program stored in the storage unit 40. The operation of each part of the machine 100 is controlled. The storage unit 40 is a large-capacity storage device such as an HDD (Hard Disk Drive), and stores various data including a program for operating each unit of the copying machine 100 described above. The storage unit 40 stores a reference table T1 indicating an area that can be reproduced only by color toner (hereinafter referred to as “non-fluorescent area”).

  The reference table T1 is a data group indicating a non-fluorescent area that can be reproduced with only color toner without using fluorescent toner. Using this reference table T1, the control unit 30 determines whether or not the color indicated by each pixel of the image data is a color belonging to the non-fluorescent region, and sets flag data representing the determination result as a pixel to be determined (hereinafter referred to as a determination target pixel). The pixel of interest is output in association with the pixel of interest. This flag data is hereinafter referred to as “fluorescence flag”. When the fluorescence flag is “0 (= NO)”, it means that the target pixel is a color belonging to the non-fluorescence region, and when the fluorescence flag is “1 (= YES)”, This means that the pixel of interest has a color that does not belong to the non-fluorescent region. For convenience of explanation, in the following, a color belonging to the non-fluorescent region is referred to as “non-fluorescent color”, and a color not belonging to the non-fluorescent region is referred to as “fluorescent color”.

FIG. 4 is a diagram for explaining the difference between the non-fluorescent color and the fluorescent color, and is a diagram showing a part of the color space in the CIELAB color system, that is, the L * a * b * color space. In the figure, the vertical axis is L *, the horizontal axis is a *, and b * is a fixed value. In the figure, the color represented by the coordinate point C ₁ is a non-fluorescent color, the color represented by the coordinate point C ₂ is a fluorescent color. In such a case, the color C ₁ belongs to the non-fluorescent region, and this non-fluorescent region is a closed region as indicated by the solid line G. That is, when the color value of the pixel of interest is represented by the CIELAB color system, if the color value is included in the non-fluorescent region G, it is a non-fluorescent color, and if it is not included in the non-fluorescent region G Fluorescent color.

  Here, referring back to FIG. 2 again, other components of the image forming unit 20 will be described. The image processing unit 50 includes an image processing circuit such as an ASIC (Application Specific Integrated Circuit) or an LSI (Large Scale Integration), and an image memory that temporarily stores image data, and executes predetermined image processing. Here, the image processing includes processes such as color space conversion, image rotation, image enlargement / reduction, under color removal (UCR) processing, screen processing and the like in addition to basic image processing such as AD conversion and shading correction. .

  The operation unit 60 is, for example, an input device including a touch panel display and various buttons, and receives an input instruction from an operator. This input instruction is supplied to the control unit 30. The communication unit 70 is an interface device for exchanging data with an external device. The copying machine 100 can output the image data generated by the image reading unit 10 to an external device such as a computer, or can receive image data from the external device as necessary.

[2. Operation]
With the configuration described above, the copying machine 100 scans the object to be imaged O placed on the platen glass 11 to generate image data indicating the object to be imaged O, and generates an image based on the image data. Form on a sheet. Hereinafter, a series of operations performed by the copying machine 100 from scanning of the object to be imaged O to image formation will be described with reference to the flowchart of FIG.

  When the object to be imaged O is placed on the platen glass 11 and the operator instructs the start of image formation, the control unit 30 of the copying machine 100 scans the object to be imaged O placed on the image reading unit 10. (Step S1). At this time, the image reading unit 10 irradiates the object to be imaged O while moving the full-rate carriage 13 and the half-rate carriage 14, images the reflected light with the line sensor 16, and each color of B, BG, G, and R The image signal is generated.

  Subsequently, the control unit 30 supplies the image signal generated by the image reading unit 10 to the image processing unit 50, and generates image data based on the image signal (step S2). This image data is image data described by the CIELAB color system, and each pixel has a color value indicated by metric brightness (L *) and chromaticity coordinates (a *, b *). At this time, the image processing unit 50 obtains image data from the above-described image signal by executing image processing such as AD conversion, shading correction, and color space conversion.

  Then, the control unit 30 sets a pixel that has not been processed as a target pixel, and performs a process of determining whether the target pixel is a color belonging to the non-fluorescent region (step S3). This process is performed using the reference table T1 described above. In this process, if the target pixel is a color value belonging to the non-fluorescent region, the control unit 30 outputs a value of “0” as the fluorescence flag, while the target pixel is a color value not belonging to the non-fluorescent region. For example, the control unit 30 outputs a value “1” as the fluorescence flag. In other words, each pixel of the image data is classified into either an image area where the fluorescence flag is “0” or an image area where the flag is “1”. The control unit 30 temporarily stores this output value in the RAM.

  The control unit 30 executes this determination process for all the pixels of the image data. That is, the control unit 30 determines whether or not there is an unprocessed pixel every time the determination process in step S3 is completed (step S4). If there is an unprocessed pixel (step S4; NO), the control unit 30 appropriately moves the position of the pixel to be processed, and executes the determination process in step S3 again.

  When the discrimination process in step S3 is executed for all the pixels of the image data (step S4; YES), the control unit 30 causes the image processing unit 50 to perform color space processing, UCR processing, and screen processing of the image data, The color and the amount of toner to be applied to the position corresponding to the pixel are determined (step S5). At this time, the image processing unit 50 converts the CIELAB color system image data into CMY color system image data, and the control unit 30 uses the color data of the image data in the image forming unit 20. Image data matching the toner to be generated is generated. That is, at this time, the control unit 30 generates image data indicating the amount of toner of each of the 12 colors described above.

  When determining the toner amount, the control unit 30 refers to the value of the fluorescence flag stored in the RAM. For the pixels belonging to the image area whose fluorescent flag is “0”, the control unit 30 sets the toner amount of the fluorescent toner to all zero, and configures the image data only with other color toners. In addition, the control unit 30 configures image data of fluorescent toner and color toner for pixels belonging to the image area having the fluorescent flag “1”. Of course, for a pixel whose image can be reproduced only with the fluorescent toner, the control unit 30 may configure the image data only with the fluorescent toner.

  Note that the toner amount of the transparent toner varies depending on the image indicated by the image data. For example, when the number of toner colors used is small, such as when the image data is monochrome document data, the control unit 30 sets the toner amount of the transparent toner to zero for this image data. In addition, when the image data is multicolored and the number of colors of toner used is increased, the control unit 30 applies a predetermined amount of transparent toner to the entire surface of the image data.

  When the image data indicating the toner amount of each color is generated, the control unit 30 supplies the image data to the image forming unit 20 and forms an image corresponding to the image data on the sheet (step S6). At this time, the image forming unit 20 selects the primary transfer unit 23 corresponding to the image data of each color, and forms an electrostatic latent image corresponding to the image data here. Thereafter, the image forming unit 20 selects a toner color developing unit (any one of 234 to 237) indicated by the image data, applies toner to the electrostatic latent image, and forms a toner image. When the toner images of the respective colors are formed in this way and each of the toner images is primarily transferred to the intermediate transfer belt 24, the image forming unit 20 secondarily transfers the toner image onto the sheet, and this is transferred to the primary fixing mechanism 27 and the secondary fixing mechanism 29. To fix and discharge. As a result, a copy, which is an image representing the object to be imaged O, is formed.

  By performing the processing described above, the copying machine 100 according to the present embodiment can reproduce not only the color of the non-fluorescent area but also the image area of fluorescent color and the image area of higher saturation. In addition, according to the copying machine 100, a light source having a spectral energy distribution over the entire visible region is used, and the reflected light from the light source is imaged by a plurality of light receiving element arrays having different spectral sensitivities. Image data that can estimate the spectral reflectance of the imaged object is generated, and the image is formed using color toner and fluorescent toner based on this image data. Things can be obtained. That is, according to the copying machine 100, it is possible to obtain a copy that more faithfully reproduces the color of the object to be imaged including the fluorescent color.

  Further, most of the copying machine 100 can adopt the same configuration as a conventional copying machine. Further, the copying machine 100 can suppress an increase in size of the apparatus by arranging a plurality of rotary type developing devices in series. Therefore, according to the copying machine 100 of the present embodiment, the above-described faithful color reproduction is possible without adopting a complicated and expensive configuration.

  Furthermore, according to the copying machine 100, the transparent toner is formed so that the image surface is uniform, thereby suppressing the occurrence of unevenness on the surface of the copy despite the use of multicolor toner. ing. As a result, it is possible to suppress the occurrence of unnatural unevenness on the surface of the copy and to enhance the aesthetics of the surface of the copy.

[3. Modified example]
In addition, this invention is not limited only to embodiment mentioned above, It is possible to implement in a various aspect. Specifically, the following modifications are mentioned, for example. These modifications can be combined as appropriate.

  In the above-described embodiment, eight colors of cyan, magenta, yellow, black, red, orange, green, and blue are standard color toners, and fluorescence that can form colors in a color region that cannot be reproduced by these color toners. Although the toner is specifically used, the color used in the present invention is not limited to such an example. For example, four colors of cyan, magenta, yellow, and black may be used as standard color toners. Further, the toner to be used specifically does not need to be a fluorescent color, and it is also possible to use a toner having a higher saturation color or metallic color than a standard toner.

  In the case where the non-fluorescent area not using the fluorescent toner is clearly distinguished from the non-fluorescent area where the fluorescent toner is not used as in the above-described embodiment, when the color image at the boundary between these color areas is formed, the boundary May appear prominently on the image. Therefore, among the colors belonging to the non-fluorescent region, in particular, the color approximate to the color reproduced using the fluorescent toner may include a small amount of fluorescent toner. As a method for determining the degree of approximation, a method based on a color difference can be considered in the above embodiment. For example, if the color difference between the two colors of the color Ca belonging to the non-fluorescent region and the color Cb located at the boundary is equal to or smaller than a predetermined threshold, the fluorescence is generated when the image of the color Ca is formed. It is only necessary to include a little toner. In this way, a more natural color reproduction can be realized.

  Of course, the number of colors used in the present invention is not limited to twelve colors, and may be increased or decreased as appropriate. In this case, the configuration of the developing device and the primary transfer unit may be changed as appropriate. When the number of colors to be used is small or when it is desired to form an image at a higher speed, the primary transfer unit may be configured without using a rotary developing device.

  In the above-described embodiment, the electrophotographic copying machine is described as an example of the image forming apparatus according to the present invention. However, the present invention can also be applied to other recording methods such as an ink jet method. Therefore, as a matter of course, what can be used as the coloring material of the present invention is not limited to toner.

  In the above-described embodiment, the fixing mechanism is provided in two stages in order to make the surface of the image formed of the transparent toner highly smooth. However, such a configuration is not necessarily required. For example, the secondary fixing mechanism 29 may be excluded and the fixing process may be performed only by the primary fixing mechanism 27. In such a configuration, it is effective to switch the fixing speed and the fixing temperature according to the toner amount and the like.

  In the above-described embodiment, the determination process is executed for each pixel of the image data to determine whether or not to use the fluorescent toner. However, for example, a pre-scan is executed and the fluorescent toner needs to be used at this time. It may be determined whether or not there is. In this way, for example, when copying a monochrome document, the above-described determination processing can be omitted, so that the processing speed can be increased. Further, a plurality of operation modes may be provided in the copying machine so that the operator can select these operations by switching.

1 is a block diagram showing a configuration of a copying machine according to an embodiment of the present invention. FIG. 2 is a diagram specifically illustrating the configuration of an image reading unit and an image forming unit of a copying machine. FIG. 2 is a diagram illustrating in detail a configuration of a primary transfer unit of a copying machine. It is a figure for demonstrating the difference between a non-fluorescent color and a fluorescent color. 6 is a flowchart illustrating an operation performed when the copying machine forms an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Copy machine, 10 ... Image reading part, 11 ... Platen glass, 12 ... Platen cover, 13 ... Full-rate carriage, 14 ... Half-rate carriage, 15 ... Imaging lens, 16 ... Line sensor, 20 ... Image formation part, 21 ... Paper feed tray, 22... Transport roll, 23, 23 a, 23 b, 23 c... Primary transfer unit, 24. Intermediate transfer belt, 25. Secondary transfer roll, 26. 29 ... secondary fixing mechanism, 30 ... control unit, 40 ... storage unit, 50 ... image processing unit, 60 ... operation unit, 70 ... communication unit

Claims (6)

An irradiating means for irradiating the imaged object with light having a spectral energy distribution over at least the entire visible region;
The light reflected by the object to be imaged of the light emitted by the irradiation unit and received by a plurality of different spectral sensitivity, and generates an image data representing the color of the object to be imaged on the basis of these received light A light receiving means;
A discriminating unit for discriminating an image region indicating a color included in a predetermined color region out of the image data generated by the light receiving unit;
An image forming unit that forms an image corresponding to the image data generated by the light receiving unit on a sheet, and for the image region that is determined to be included in the color region by the determining unit, An image is formed using a standard color material, which is a plurality of color materials that express colors included in the color region by a combination, and for other image regions, included in the color region among the colors indicated by the image data An image forming apparatus comprising: an image forming unit that forms an image using at least a specific color material that is a color material capable of forming an image of an uncolored color. The light receiving means is
The image forming apparatus according to claim 1, wherein the image forming apparatus includes a plurality of light receiving element arrays of at least four lines, and each light receiving element array has different spectral sensitivities. The image forming unit includes:
An image showing a color whose difference from a color not included in the color area is equal to or lower than a predetermined level among colors included in the color area is formed using the standard color material and the specific color material. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1, wherein the image forming unit is an electrophotographic image forming unit, and includes a plurality of rotary type developing units. The image forming apparatus according to claim 4, wherein the standard color material includes cyan, magenta, yellow, and black toner. The image forming apparatus according to claim 4, wherein the specific color material includes fluorescent toner.

Images