Image forming system

Abstract

To increase the hiding rate of colors of a recording medium in a composition in which a toner image formed on an intermediate transfer body is transferred to the recording medium, as compared with a composition where, when the color of the recording medium is a predetermined color, only a white toner image is superimposed multiple times on the surface of the intermediate transfer body.SOLUTION: An image forming system comprises: an intermediate transfer body on which surface a toner image is formed, and which transfers the toner image to a recording medium; a white toner image forming unit capable of forming a white toner image in white color on the surface of the intermediate transfer body; a silver toner image forming unit provided downstream of the white toner image forming unit and capable of forming a silver toner image in silver color on the intermediate transfer body; and a processor. When the color of the recording medium is a predetermined color, the processor causes the silver toner image to be superimposed on the white toner image formed on the surface of the intermediate transfer body.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to imaging systems. [Background technology]

[0002] Patent Document 1 discloses a toner for developing electrostatic images, which is characterized by containing needle-shaped titanium oxide having an average aspect ratio in the range of 3 to 30 as a white pigment.

[0003] Patent Document 2 discloses an image forming apparatus having an image forming unit that forms a flat pigment toner image with a flat pigment toner containing a flat pigment, forms a white toner image with a white toner, and forms a color toner image with the flat pigment toner and color toners other than the white toner, and has a mode in which base layers are formed in at least the image forming area of ​​a recording medium in the following order with respect to the viewing direction: a first base layer made of the white toner, and a second base layer made of the flat pigment toner.

[0004] Patent document 3 discloses an image forming apparatus comprising: a first forming unit that forms a superimposed toner image in which yellow, magenta, and cyan toner images are superimposed on a first intermediate transfer unit; a second forming unit that is arranged downstream of the first forming unit in the transport direction of the recording medium and forms a black toner image in a second intermediate transfer unit; a first transfer unit that transfers the superimposed toner image formed in the first intermediate transfer unit by the first forming unit to the recording medium; and a second transfer unit that is arranged downstream of the first transfer unit in the transport direction of the recording medium and transfers the black toner image formed in the second intermediate transfer unit by the second forming unit so as to be superimposed on the superimposed toner image on the recording medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-45225 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-40910 [Patent Document 3] Japanese Patent Publication No. 2020-52094 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure aims to increase the concealment rate of the color of a recording medium in a configuration in which a toner image formed on an intermediate transfer body is transferred to a recording medium when the color of the recording medium is a predetermined color, compared to a configuration in which only a white toner image is superimposed multiple times on the surface of the intermediate transfer body. [Means for solving the problem]

[0007] A first aspect of the present disclosure is an image forming system comprising: an intermediate transfer body on whose surface a toner image is formed and which transfers the toner image to a recording medium; a white toner image forming unit capable of forming a white toner image on the surface of the intermediate transfer body; a silver toner image forming unit located downstream of the white toner image forming unit and capable of forming a silver toner image on the surface of the intermediate transfer body; and a processor, wherein the processor overlays the silver toner image on the layer of white toner image formed on the surface of the intermediate transfer body when the color of the recording medium is a predetermined color.

[0008] A second aspect of the present disclosure is an image forming system according to the first aspect, which includes a plurality of the white toner image forming units, and a processor which overlaps the plurality of white toner images to form a layer of the white toner image.

[0009] A third aspect of the present disclosure is the image forming system of the first or second aspect, wherein the processor changes the densities of the white toner and the silver toner depending on the color of the recording medium.

[0010] A fourth aspect of the present disclosure is an image forming system according to the second aspect, wherein the processor forms a layer of the white toner image by overlapping multiple white toner images with a toner concentration of 100% according to the color of the recording medium, and overlaps the silver toner image with a toner concentration of 10% or more and 40% or less on the layer of the white toner image.

[0011] A fifth aspect of the present disclosure is an image forming system of the first or second aspect, which is provided with a colorimetry unit that measures the color of the recording medium, and the processor acquires information regarding the color of the recording medium from the colorimetry unit.

[0012] A sixth aspect of the present disclosure is an image forming system according to the first or second aspect, wherein the processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a lightness L* of L*<50 in the Lab color space.

[0013] A seventh aspect of the present disclosure is an image forming system according to the first or second aspect, wherein the processor overlays the silver toner image on a layer of the white toner image when the color of the recording medium has a chromaticity b* of 30>b*>-30 in the Lab color space.

[0014] An eighth aspect of the present disclosure is an image forming system according to the first or second aspect, wherein the processor overlays the silver toner image on a layer of the white toner image when the color of the recording medium has a chromaticity a* of a*<-30 or a*>+30 in the Lab color space. [Effects of the Invention]

[0015] In the image forming system of the first embodiment, in a configuration in which a toner image formed on an intermediate transfer body is transferred to a recording medium, when the color of the recording medium is a predetermined color, the concealment rate of the color of the recording medium is higher than in a configuration in which only a white toner image is superimposed multiple times on the surface of the intermediate transfer body.

[0016] In the image forming system of the second embodiment, the concealment rate of the color of the recording medium is higher than in a configuration in which the white toner image layer is formed by a single white toner image.

[0017] In the image forming system of the third embodiment, the hiding rate of the color of the recording medium is higher than in a configuration in which the densities of the white toner and silver toner are constant.

[0018] In the fourth embodiment of the image forming system, compared to a configuration in which the silver toner concentration does not satisfy the range of 10% to 40%, it is possible to increase the concealment rate of the color of the recording medium while suppressing the silver color of the background from showing through.

[0019] In the image forming system of the fifth aspect, the color of the recording medium can be obtained more accurately than in a configuration in which the user sets the color.

[0020] In the image forming system of the sixth aspect, when the color of the recording medium is L*>50 in the Lab color space, the amount of toner consumed can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of a white toner image.

[0021] In the seventh embodiment of the image forming system, when the color of the recording medium is b*<-30 or b*>30 in the Lab color space, the amount of toner consumed can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of a white toner image.

[0022] In the image forming system of the eighth aspect, when the color of the recording medium is 30>a*>-30 in the Lab color space, the amount of toner consumed can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of a white toner image. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram illustrating an image forming unit and a fixing unit of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] 1 is a block diagram showing a hardware configuration of an image forming apparatus according to an embodiment of the present disclosure. [Figure 3]1 is a schematic diagram of a measurement unit, an image forming unit, and a fixing unit of an image forming apparatus according to an embodiment of the present disclosure. [Figure 4] 10 is a flowchart for explaining a process of superimposing a silver toner image on a white toner image layer on the surface of an intermediate transfer body using an image forming apparatus according to an embodiment of the present disclosure. [Figure 5] 2 is a side cross-sectional view of the intermediate transfer member in the image forming apparatus shown in FIG. 1, showing a state in which a white toner image has been formed on the surface of the intermediate transfer member. FIG. [Figure 6] 2 is a side cross-sectional view of the intermediate transfer body in the image forming apparatus shown in FIG. 1, showing a state in which a white toner image layer is formed by superimposing a white toner image on a white toner image formed on the surface of the intermediate transfer body. FIG. [Figure 7] 2 is a side cross-sectional view of the intermediate transfer member in the image forming apparatus shown in FIG. 1, showing a state in which a silver toner image is superimposed on a white toner image layer formed on the surface of the intermediate transfer member. FIG. [Figure 8] 2 is a side cross-sectional view of a recording medium in the image forming apparatus shown in FIG. 1, showing a state in which a toner image formed on the surface of an intermediate transfer member has been transferred onto the recording medium. [Figure 9] FIG. 10 is a schematic diagram of a measurement unit, an image forming unit, and a fixing unit of an image forming apparatus according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] An image forming apparatus 20 as an example of an image forming system according to an embodiment of the present disclosure will be described with reference to FIGS.

[0025] Arrow H shown in each figure indicates the up-down direction of image forming apparatus 20 (specifically, the vertical direction). Arrow W indicates the width direction of image forming apparatus 20 (specifically, the horizontal direction). Arrow D indicates the depth direction of image forming apparatus 20 (specifically, the horizontal direction). The up-down direction, width direction, and depth direction of image forming apparatus 20 intersect (specifically, are perpendicular to) each other. Note that the present disclosure is not limited to this configuration, and the width direction may be the depth direction of the apparatus, and the depth direction may be the width direction of the apparatus.

[0026] Furthermore, components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of the elements shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of the elements do not necessarily match between multiple drawings.

[0027] 1, the image forming apparatus 20 according to this embodiment is an apparatus that forms an image on a recording medium P. Specifically, the image forming apparatus 20 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on the recording medium P. Note that, in this embodiment, paper is used as an example of the recording medium P, but the present invention is not limited to this.

[0028] The image forming apparatus 20 includes an image forming section 22 and a fixing section 24. Each section of the image forming apparatus 20 (the image forming section 22 and the fixing section 24) will be described below.

[0029] (Image forming unit 22) 1, the image forming section 22 has a function of forming a toner image (also referred to as a toner image) on a recording medium P. Specifically, the image forming section 22 has a plurality of image forming units 30 and a transfer section 40.

[0030] A plurality of image forming units 30 are provided on a surface 42A of a transfer belt 42, which will be described later, at intervals in a rotation direction A of the transfer belt 42. Note that, as an example, the image forming section 22 of this embodiment includes two image forming units 30 that form white (W) toner images, one image forming unit 30 that forms silver (S) toner images, and one image forming unit 30 that forms black (K) toner images.

[0031] A white image forming unit 30, a silver image forming unit 30, and a black image forming unit 30 are provided in this order from upstream in the rotation direction A of the transfer belt 42. Of the two white image forming units 30, the image forming unit 30 located upstream in the rotation direction A is referred to as image forming unit 30(W1), and the other is referred to as image forming unit 30(W2). Similarly, the silver image forming unit 30 is referred to as image forming unit 30(S), and the black image forming unit 30 is referred to as image forming unit 30(K).

[0032] The image forming units 30(W1) and 30(W2) of this embodiment are an example of a white toner image forming section capable of forming a white toner image on the surface 42A of the transfer belt 42. The image forming unit 30(S) is provided downstream of the image forming units 30(W1) and 30(W2) in the rotation direction A, and is an example of a silver toner image forming section capable of forming a silver toner image on the surface 42A of the transfer belt 42.

[0033] 1, each image forming unit 30 is configured similarly except for the toner used. For this reason, in FIG. 1, the components of image forming unit 30(W1) are denoted by reference numerals to represent each image forming unit 30.

[0034] Specifically, each image forming unit 30 has a photosensitive drum 32 that rotates in one direction (for example, clockwise in FIG. 1). Here, the photosensitive drum 32 is an example of an image carrier. Furthermore, each image forming unit 30 has a charger 34, an exposure device 36, and a developing device 38.

[0035] In each image forming unit 30, a charger 34 charges a photosensitive drum 32. An exposure device 36 exposes the photosensitive drum 32 charged by the charger 34 to light to form an electrostatic latent image on the photosensitive drum 32. A developing device 38 develops the electrostatic latent image formed on the photosensitive drum 32 by the exposure device 36 to form a toner image.

[0036] The photosensitive drum 32 rotates while holding the electrostatic latent image formed as described above on its outer periphery, and the electrostatic latent image is transported to the developing device 38 .

[0037] 1, the transfer unit 40 has a function of transferring the toner image formed by the image forming unit 30 onto a recording medium P. Specifically, the transfer unit 40 performs primary transfer of the toner image on each photosensitive drum 32 onto a transfer belt 42 serving as an intermediate transfer body, and then performs secondary transfer of the superposed toner image onto the recording medium P. Specifically, as shown in FIG. 1, the transfer unit 40 includes the transfer belt 42, a primary transfer roll 44, and a secondary transfer roll 46.

[0038] The primary transfer roll 44 is a roll that transfers the toner image on each photosensitive drum 32 to the transfer belt 42 at a primary transfer position T1 between the photosensitive drum 32 and the primary transfer roll 44. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 44 and the photosensitive drum 32, so that the toner image formed on the photosensitive drum 32 is transferred to the transfer belt 42 at the primary transfer position T1.

[0039] The toner images are transferred from each photosensitive drum 32 to a surface 42A, which serves as the outer peripheral surface, of the transfer belt 42. As shown in Fig. 1, the transfer belt 42 is an endless band having a circular shape, and its position is determined by being wound around a plurality of rolls 48.

[0040] The transfer belt 42 rotates in the direction of arrow A when, for example, a drive roll 48D among the plurality of rolls 48 is driven to rotate by a driving force from a drive source (not shown). Of the plurality of rolls 48, roll 48B shown in FIG. 1 is an opposing roll 48B that faces the secondary transfer roll 46.

[0041] The secondary transfer roll 46 is a roll that transfers the toner image transferred to the transfer belt 42 to the recording medium P at a secondary transfer position T2 between the opposing roll 48B and the secondary transfer roll 46. In this embodiment, a secondary transfer electric field is applied between the opposing roll 48B and the secondary transfer roll 46, so that the toner image transferred to the transfer belt 42 is transferred to the recording medium P at the secondary transfer position T2.

[0042] (Fixing unit 24) 1, the fixing unit 24 has a function of fixing the toner image transferred to the recording medium P by the secondary transfer roll 46 to the recording medium P. Specifically, the fixing unit 24 has a heating roll 24A as a heating member and a pressure roll 24B as a pressure member. In the fixing unit 24, the toner image formed on the recording medium P is fixed to the recording medium P by heating and pressurizing the recording medium P with the heating roll 24A and the pressure roll 24B.

[0043] As shown in FIG. 2, the image forming apparatus 20 includes a processor 100, a storage unit 102, an operation unit 104, a display unit 106, a communication unit 108, a color measurement unit 110, an image forming unit 22, an image reading unit 26, and the like.

[0044] (Processor 100) The processor 100 includes a CPU (Central Processing Unit) 100A, a ROM (Read Only Memory) 100B, a RAM (Random Access Memory) 100C, and an input / output interface (I / O) 100D. The processor 100 controls the overall operation of the image forming apparatus 20. For example, various control programs and various parameters are stored in advance in the ROM 100B. The RAM 100C is used as a work area when the CPU 100A executes various programs.

[0045] The storage unit 102 stores various programs and data for executing print processing, application programs, and the like.

[0046] The operation unit 104 is used to input various types of information.

[0047] The display unit 106 is used to display various types of information.

[0048] The communication unit 108 is an interface for transmitting and receiving various data to and from an external device such as a server, etc. The communication unit 108 may be configured to be capable of directly communicating with each device using short-range wireless communication such as Wi-Fi (registered trademark) or Bluetooth (registered trademark).

[0049] As shown in FIG. 3, the colorimetric unit 110 is disposed upstream of the image forming unit 22 in the transport direction B of the recording medium P. The colorimetric unit 110 has a function of measuring the color of the recording medium P. The colorimetric unit 110 can, for example, irradiate the recording medium P with light of multiple different wavelengths and measure the color based on the wavelength and intensity of the light reflected by the recording medium P. Information (color information) about the color of the recording medium P measured by the colorimetric unit 110 is stored in, for example, the RAM 100C or the storage unit 102. Note that the colorimetric method is not limited to the above method as long as it can measure the color of the recording medium P.

[0050] 3, the image forming device 20 is disposed on a transport path of the recording medium P by the transport roll 50, but the present disclosure is not limited to this configuration. The image forming device 20 may include a paper feed unit (not shown), and the transport roll 50 may be provided on a transport path from the paper feed unit to the image forming unit 22. In this case, the color measurement unit 110 may be provided between the paper feed unit and the image forming unit 22.

[0051] The image reading unit 26 has a function of reading an image of a document set in the image forming apparatus 20. The image forming apparatus 20 of the present embodiment includes the image reading unit 26 as an example, but the present disclosure is not limited to this configuration, and the image reading unit 26 may not be included.

[0052] As shown in FIG. 2, the components of the image forming apparatus 20 are electrically connected to one another via a system bus.

[0053] Next, the operation of the processor 100 of this embodiment will be described. When the color of the recording medium P is a predetermined color, the processor 100 causes a silver toner image T(S) to be superimposed on the layer R(W) of the white toner image formed on the surface 42A of the transfer belt 42. Specifically, the processor 100 obtains color information of the recording medium P on which image formation is to be performed from the RAM 100C or the storage unit 102. Similarly, the processor 100 obtains predetermined color information from the ROM 100B, the RAM 100C, or the storage unit 102. Then, when the color information of the recording medium P is the same as the predetermined color information, the processor 100 causes a silver toner image T(S) to be superimposed on the layer R(W) of the white toner image formed on the surface 42A of the transfer belt 42.

[0054] Here, for example, when the color information of the recording medium P is predetermined first color information, the processor 100 forms a white toner image T(W1) on the surface 42A of the transfer belt 42 and overlays a silver toner image T(S) on the layer R(W) of the formed white toner image T(W1). On the other hand, when the color information of the recording medium P is predetermined second color information, the processor 100 overlays a white toner image T(W2) on the white toner image T(W1) formed on the surface 42A of the transfer belt 42 to form a white toner image layer R(W), and overlays a silver toner image T(S) on the white toner image layer R(W). That is, the processor 100 may form the white toner image layer R(W) by overlaying a single white toner image or multiple white toner images according to the color information of the recording medium P. Note that the second color information is set to color information (e.g., red or green) that allows the underlying color of the recording medium P to more easily show through when silver toner and white toner are overlaid on the recording medium P, as compared to the first color information.

[0055] Processor 100 may also change the densities of the white toner and the silver toner depending on the color of recording medium P. Specifically, processor 100 may change the densities of the white toner and the silver toner depending on the color information of recording medium P. For example, when the color information of recording medium P is first color information, processor 100 may overlay a silver toner image T(S) having a toner concentration of 10% or more and 40% or less on a layer R(W) of a white toner image having a toner concentration of 100%, or when the color information of recording medium P is second color information, processor 100 may overlay a silver toner image T(S) having a toner concentration of 10% or more and 40% or less on a layer R(W) of a white toner image formed by overlaying multiple white toner images having a toner concentration of 100%.

[0056] Note that the processor 100 may form a white toner image layer R(W) by overlapping multiple white toner images with a toner concentration of 100%, regardless of the color of the recording medium P, and then overlap this white toner image layer R(W) with a silver toner image T(S) whose toner concentration is changed within a range of 10% to 40% depending on the color of the recording medium P. However, when overlapping multiple white toner images, it is preferable to set the number of overlaps of the white toner image to about two times so that the thickness of the white toner image layer R(W) does not become too thick.

[0057] The "toner density" referred to here is the density when the maximum amount of toner that can be transferred onto the surface 42A of the transfer belt 42 in one transfer with one developing device 38 is taken as 100%.

[0058] In addition, the processor 100 may convert the acquired color information of the recording medium P into the Lab color space, and if the converted value satisfies the lightness L* in the Lab color space of L*<50, the silver toner image T(S) may be superimposed on the white toner image layer R(W).

[0059] The processor 100 may also convert the acquired color information of the recording medium P into the Lab color space, and if the chromaticity b* of the converted value in the Lab color space is 30>b*>-30, overlay the silver toner image T(S) on the white toner image layer R(W).

[0060] In addition, the processor 100 may convert the acquired color information of the recording medium P into the Lab color space, and if the chromaticity a* of the converted value in the Lab color space is a*<-30 or a*>+30, the processor 100 may overlay the silver toner image T(S) on the white toner image layer R(W).

[0061] In this embodiment, as an example, the processor 100 converts the acquired color information of the recording medium P into the Lab color space, and if the converted values ​​satisfy the following conditions in the Lab color space: lightness L*<50, chromaticity b*<30>b*>-30, and chromaticity a*<-30 or a*>+30, then the processor 100 overlays the silver toner image T(S) on the white toner image layer R(W).

[0062] Next, the process of forming a white toner image layer R(W) on the surface 42A of the transfer belt 42 using the image forming apparatus 20 of this embodiment and then overlaying a silver toner image T(S) thereon will be described with reference to the flowchart shown in FIG.

[0063] When the image forming device 20 forms a toner image on the transfer belt 42, the processor 100 acquires color information of the recording medium P on which the image is to be formed (step S200).

[0064] Next, in step S202, the processor 100 obtains predetermined color information and compares it with the color information of the recording medium P. If the color information of the recording medium P is the same as the predetermined color information, the processor 100 proceeds to step S204. On the other hand, if the color information of the recording medium P is not the same as the predetermined color information, the processor 100 proceeds to step S208. In step S208, the processor 100 forms only a white toner image layer R(W) on the surface 42A of the transfer belt 42 and ends the process. In step S208, the white toner image layer R(W) may be formed by overlapping multiple white toner images, or the toner density may be changed according to the color information of the recording medium P.

[0065] In step S204, the processor 100 forms a layer R(W) of a white toner image on the surface 42A of the transfer belt 42. In this embodiment, as an example, as shown in FIG. 5, a white toner image T(W1) with a toner concentration of 100% is formed on the surface 42A of the transfer belt 42 by the image forming unit 30(W1). Next, as shown in FIG. 6, a white toner image T(W2) with a toner concentration of 100% is superimposed on the white toner image T(W1) by the image forming unit 30(W2). As a result, a layer R(W) of a white toner image is formed on the surface 42A of the transfer belt 42.

[0066] In step S206, the processor 100 superimposes a silver toner image T(S) with a toner concentration of 10% to 40% on the white toner image layer R(W), as shown in Fig. 7. As a result, a toner image is formed on the surface 42A of the transfer belt 42, in which the white toner image layer R(W) and the silver toner image T(S) are superimposed.

[0067] The toner image formed on the surface 42A of the transfer belt 42 is transferred to the recording medium P by secondary transfer, as shown in Fig. 8. Then, the toner image transferred to the recording medium P is fixed to the recording medium P by the fixing unit 24.

[0068] Next, the effects of this embodiment will be described. In the image forming apparatus 20 serving as the image forming system of this embodiment, when the color of the recording medium P is a predetermined color, the processor 100 causes a silver toner image T(S) to be superimposed on the layer R(W) of the white toner image formed on the surface 42A of the transfer belt 42. Therefore, in the image forming apparatus 20, when the color (color information) of the recording medium P is a predetermined color, the concealment rate of the color of the recording medium P is higher than in a configuration in which only white toner images are superimposed multiple times on the surface 42A of the transfer belt 42. In other words, the background color, which is the color of the recording medium P, is prevented from showing through.

[0069] Furthermore, in the image forming apparatus 20 of this embodiment, the processor 100 may form a white toner image layer R(W) by overlapping a plurality of white toner images. In this case, the image forming apparatus 20 has a higher hiding rate for the color of the recording medium P compared to a configuration in which the white toner image layer R(W) is formed with a single white toner image.

[0070] Furthermore, in the image forming apparatus 20 of this embodiment, the processor 100 may change the density of the white toner and silver toner depending on the color of the recording medium P. In this case, the image forming apparatus 20 has a higher hiding rate for the color of the recording medium P compared to a configuration in which the density of the white toner and silver toner is constant. In addition, it becomes possible to reduce the amount of toner consumed.

[0071] Furthermore, in the image forming apparatus 20 of this embodiment, the processor 100 may form a white toner image layer R(W) by overlapping multiple white toner images with a toner concentration of 100%, depending on the color of the recording medium P, and may overlap a silver toner image T(S) with a toner concentration of 10% to 40% on the white toner image layer R(W). In this case, the image forming apparatus 20 can increase the concealment rate of the color of the recording medium P while suppressing the silver color of the background from showing through, compared to a configuration in which the concentration of the silver toner does not satisfy the condition of 10% to 40%.

[0072] Furthermore, in the image forming apparatus 20 of this embodiment, the processor 100 may acquire information about the color of the recording medium P from the colorimetric unit 110. In this case, the image forming apparatus 20 can acquire the color of the recording medium P more accurately than in a configuration in which the user sets the color.

[0073] Furthermore, in the image forming apparatus 20 of this embodiment, when the color of the recording medium P has a lightness L* that satisfies L*<50 in the Lab color space, the processor 100 may overlay the silver toner image T(S) on the white toner image layer R(W). In this case, the image forming apparatus 20 can reduce toner consumption compared to a configuration in which the silver toner image T(S) is overlaid on the white toner image layer R(W) when the color of the recording medium P has a lightness L*>50 in the Lab color space.

[0074] Furthermore, in the image forming apparatus 20 of this embodiment, when the color of the recording medium P has a chromaticity b* of 30>b*>-30 in the Lab color space, the processor 100 may overlay the silver toner image T(S) on the white toner image layer R(W). In this case, the image forming apparatus 20 can reduce toner consumption compared to a configuration in which the silver toner image T(S) is overlaid on the white toner image layer R(W) when the color of the recording medium P has a chromaticity b* of 30>b*>-30 in the Lab color space.

[0075] Furthermore, in the image forming apparatus 20 of this embodiment, when the color of the recording medium P has a chromaticity a* of a*<-30 or a*>+30 in the Lab color space, the processor 100 may overlay the silver toner image T(S) on the white toner image layer R(W). In this case, the image forming apparatus 20 can reduce toner consumption compared to a configuration in which the silver toner image T(S) is overlaid on the white toner image layer.

[0076] (Other embodiments) In the above-described embodiment, the colorimetric unit 110 is provided inside the housing of the image forming apparatus 20, but the present disclosure is not limited to this configuration. For example, as in the image forming apparatus 90 shown in FIG. 9 , the colorimetric unit 110 may be provided in a housing separate from the housing of the image forming apparatus 90. In this case, the colorimetric unit 110 is disposed upstream of the image forming apparatus 90 in the conveying direction B of the recording medium P. Note that color information of the recording medium P measured by the colorimetric unit 110 may be stored in the RAM 100C or the storage unit 102 via the communication unit 108, for example.

[0077] In the above-described embodiment, the image forming apparatus 20 includes the colorimetric unit 110, but the present disclosure is not limited to this configuration, and the image forming apparatus 20 may not include the colorimetric unit 110. In this case, the color information of the recording medium P may be set by the user using the operation unit 104. Furthermore, the color information of the recording medium P may be set externally via the communication unit 108.

[0078] In the above-described embodiment, the image forming apparatus 20 includes four image forming units 30, but the present disclosure is not limited to this configuration, and the image forming apparatus 20 may include other image forming units 30. For example, the image forming apparatus 20 may include image forming units 30 for a total of three colors: yellow (Y), magenta (M), and cyan (C).

[0079] The present disclosure is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit of the present disclosure. For example, the above-described modified examples may be appropriately combined to form a configuration.

[0080] The following additional notes are provided regarding the above-described embodiments.

[0081] (((1))) an intermediate transfer member on whose surface a toner image is formed and which transfers the toner image onto a recording medium; a white toner image forming unit capable of forming a white toner image on the surface of the intermediate transfer body; a silver toner image forming unit that is provided downstream of the white toner image forming unit and that is capable of forming a silver toner image on the surface of the intermediate transfer body; a processor; Equipped with The processor overlays a silver toner image on a white toner image layer formed on the surface of the intermediate transfer body when the color of the recording medium is a predetermined color. Imaging system.

[0082] (((2))) a plurality of the white toner image forming units; The processor overlaps the plurality of white toner images to form a layer of the white toner image. The image forming system according to (((1))).

[0083] (((3))) The processor varies the density of the white toner and the silver toner depending on the color of the recording medium. The image forming system according to (((1))) or (((2))).

[0084] (((4))) the processor, according to the color of the recording medium, causes a plurality of the white toner images each having a toner concentration of 100% to be superimposed to form a layer of the white toner image, and causes the silver toner image each having a toner concentration of 10% or more and 40% or less to be superimposed on the layer of the white toner image; The image forming system according to (((2))).

[0085] (((5))) a colorimetric unit that measures the color of the recording medium; The processor acquires information about the color of the recording medium from the color measurement unit. The image forming system according to any one of (((1))) to (((4))).

[0086] (((6))) The processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a lightness L* of L*<50 in the Lab color space. The image forming system according to any one of (((1))) to (((5))).

[0087] (((7))) The processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a chromaticity b* of 30>b*>-30 in the Lab color space. The image forming system according to any one of (((1))) to (((6))).

[0088] (((8))) The processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a chromaticity a* of a*<-30 or a*>+30 in the Lab color space. The image forming system according to any one of (((1))) to (((7))).

[0089] In the image forming system (((1))), in a configuration in which a toner image formed on an intermediate transfer body is transferred to a recording medium, when the color of the recording medium is a predetermined color, the concealment rate of the color of the recording medium is higher than in a configuration in which only a white toner image is superimposed multiple times on the surface of the intermediate transfer body.

[0090] In the image forming system (((2))), the concealment rate of the color of the recording medium is higher than in a configuration in which the white toner image layer is formed by a single white toner image.

[0091] In the image forming system (((3))), the hiding rate of the color of the recording medium is higher than in a configuration in which the densities of the white toner and silver toner are constant.

[0092] In the image forming system (((4))), the concealment rate of the color of the recording medium can be increased while suppressing the silver color of the background from showing through, compared to a configuration in which the concentration of the silver toner does not satisfy the range of 10% to 40%.

[0093] In the image forming system (((5))), the color of the recording medium can be obtained more accurately than in a configuration in which the user sets the color.

[0094] In the image forming system (((6))), when the color of the recording medium is L*>50 in the Lab color space, the amount of toner consumed can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of white toner image.

[0095] In the image forming system (((7))), when the color of the recording medium is b*<-30 or b*>30 in the Lab color space, toner consumption can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of white toner image.

[0096] In the image forming system (((8))), when the color of the recording medium is 30>a*>-30 in the Lab color space, the amount of toner consumed can be reduced compared to a configuration in which a silver toner image is overlaid on a layer of white toner image. [Explanation of symbols]

[0097] 20 Image forming device 22 Image forming unit 24 Fixing section 24A heated roll 24B pressure roll 26 Image reading unit 30 Image forming unit 30(W1) Image forming unit (an example of a white toner image forming unit) 30(W2) Image forming unit (an example of a white toner image forming unit) 30(S) Image forming unit (an example of a silver toner image forming unit) 30(K) Image forming unit 32 Photosensitive drum 34 Charger 36 Exposure equipment 38 Developing device 40 Transfer unit 42 Transfer belt (an example of an intermediate transfer body) 42A surface 44 Primary transfer roll 46 Secondary transfer roll 48 rolls 48B Opposed Roll 48D driving roll 50 transport rolls 90 Image forming device 100 processors 100A CPU 100B ROM 100C RAM 100D Input / Output Interface 102 Storage section 104 Operation section 106 Display section 108 Communications Department 110 Color measurement section T(W1) White toner image T(W2) White toner image T(S) Silver toner image R(W) White toner image layer P Recording medium

Claims

1. an intermediate transfer member on whose surface a toner image is formed and which transfers the toner image onto a recording medium; a white toner image forming unit capable of forming a white toner image on the surface of the intermediate transfer body; a silver toner image forming unit that is provided downstream of the white toner image forming unit and that is capable of forming a silver toner image on the surface of the intermediate transfer body; a processor; Equipped with The processor overlays a silver toner image on a white toner image layer formed on the surface of the intermediate transfer body when the color of the recording medium is a predetermined color. Imaging system.

2. a plurality of the white toner image forming units; The processor overlaps the plurality of white toner images to form a layer of the white toner image. The image forming system according to claim 1 .

3. The processor varies the density of the white toner and the silver toner depending on the color of the recording medium.

3. The image forming system according to claim 1.

4. The processor forms a layer of the white toner image by overlapping a plurality of the white toner images having a toner concentration of 100% according to the color of the recording medium, and overlaps the silver toner image having a toner concentration of 10% to 40% on the layer of the white toner image. The image forming system according to claim 2 .

5. a colorimetric unit that measures the color of the recording medium; The processor acquires information about the color of the recording medium from the color measurement unit.

3. The image forming system according to claim 1.

6. The processor overlays the silver toner image on the white toner image layer when the color of the recording medium satisfies a lightness L* of L*<50 in the Lab color space.

3. The image forming system according to claim 1.

7. The processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a chromaticity b* of 30>b*>-30 in the Lab color space.

3. The image forming system according to claim 1.

8. The processor overlays the silver toner image on the white toner image layer when the color of the recording medium has a chromaticity a* of a*<-30 or a*>+30 in the Lab color space.

3. The image forming system according to claim 1.

Images