JP2020034593A - Image formation device and image formation system - Google Patents

Abstract

To suppress the generation of a gloss difference in an image of the same recording medium in comparison with a case of forming a transparent toner image regardless of the number of times of fixing applied to a toner image on a recording medium.SOLUTION: An image formation device includes: first image formation means 2 for forming a toner image in a recording medium; second image formation means 3 for forming by overlapping a transparent toner image on the toner image in the recording medium; one or more fixing means for fixing so that a plurality of times of fixing processing is applied to at least a part of the toner images in the recording medium; and selection means 4 for selecting the toner image in the recording medium, which is formed by the second image formation means overlapping the transparent toner image according to the number of times of the fixing processing applied to the toner image in the recording medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus and an image forming system.

  2. Description of the Related Art Conventionally, there is an image forming apparatus configured to control gloss of an image formed on a recording sheet by using a transparent toner. As techniques related to such an image forming apparatus, for example, techniques disclosed in Patent Documents 1 and 2 and the like have already been proposed.

  Japanese Patent Application Laid-Open No. H11-216,1992 is configured to correct the toner amount of the transparent toner in a portion where the transparent toner is superimposed on the color toner image in accordance with a value relating to the toner amount of the color toner image and the temperature of the recording material.

  Patent Document 2 discloses a configuration in which a transparent image is superimposed on a colored image fixed on a discharged recording sheet in accordance with the density of toner on the recording sheet on which the colored image is fixed or the toner height on the recording sheet. It is.

Japanese Patent No. 5610928 JP 2008-145595 A

  An object of the present invention is to suppress the occurrence of a gloss difference in an image on the same recording medium as compared to a case where a transparent toner image is formed irrespective of the number of fixings received by the toner image on the recording medium. .

According to the first aspect of the present invention, a first image forming means for forming a toner image on a recording medium,
Second image forming means for forming a transparent toner image by superimposing the toner image on the recording medium;
A single or a plurality of fixing means for fixing at least a part of the toner image of the recording medium to undergo a plurality of fixing processes,
Selecting means for selecting the toner image of the recording medium on which the second image forming means forms the transparent toner image by superimposing, in accordance with the number of times of the fixing process received by the toner image of the recording medium;
It is an image forming apparatus provided with.

  The invention according to claim 2 is the image forming apparatus according to claim 1, wherein the selection unit selects a toner image having a smaller number of times of the fixing process than a toner image having a largest number of times of the fixing process.

  The invention according to claim 3 is the image forming apparatus according to claim 2, wherein the selection unit changes the toner amount of the transparent toner image according to the number of times of the fixing process.

  In the invention described in claim 4, the selection unit increases the toner amount of the transparent toner image superimposed on the toner image having a small toner amount when the number of times of the fixing processing of the toner image is the same. An image forming apparatus according to claim 3.

  The invention according to claim 5, wherein the selection unit changes the toner amount of the transparent toner image according to a total toner amount of the toner image formed by the first image forming unit. An image forming apparatus according to any one of the above.

  In the invention described in claim 6, the selection unit forms the transparent toner image on a toner image in which the total toner amount of the toner image formed by the first image forming unit is smaller than the largest toner image. An image forming apparatus according to claim 5.

The invention according to claim 7, wherein the first image forming means forms the toner images on both surfaces of the recording medium,
The selecting unit may be configured such that the second image forming unit superimposes the transparent toner image on at least one surface of the recording medium in accordance with the number of times of the fixing process received by the toner images formed on both surfaces of the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed together.

  9. The image forming apparatus according to claim 8, wherein the selecting unit is configured to control the toner on a surface opposite to a surface on which the toner image having the largest number of fixing processes is present in the toner images formed on both surfaces of the recording medium. 8. The image forming apparatus according to claim 7, wherein the image is selected.

  The invention described in claim 9 is the image forming apparatus according to any one of claims 1 to 8, wherein the selection unit forms the transparent toner image on an arbitrary layer among the toner images on the recording medium. .

  The image forming apparatus according to any one of claims 1 to 9, wherein the first image forming unit and the second image forming unit are different image forming apparatuses each including the fixing unit. It is a forming system.

  According to the first aspect of the present invention, a gloss difference occurs in an image on the same recording medium as compared with a case where a transparent toner image is formed irrespective of the number of times the toner image on the recording medium is fixed. Can be suppressed.

  According to the invention as set forth in claim 2, the selection unit performs the number of times of the fixing process as compared with a case where the toner image with the smaller number of the fixing processes is not selected from the toner image with the largest number of the fixing processes. The gloss of a toner image with less toner can be improved.

  According to the invention described in claim 3, the selection unit is configured to control the toner generated by the difference in the number of times of the fixing process as compared with a case where the toner amount of the transparent toner image is not changed according to the number of times of the fixing process. The gloss difference of the image can be reduced.

  According to the invention described in claim 4, when the number of times of the fixing process of the toner image is the same, the selecting unit determines a toner amount of the transparent toner image to be superimposed on the toner image having a small toner amount. As compared with a case where the toner image is not increased, a difference in gloss due to a difference in toner amount of the toner image can be suppressed.

  According to the fifth aspect of the present invention, the selection unit does not change the toner amount of the transparent toner image according to the total toner amount of the toner image formed by the first image forming unit. Thus, it is possible to suppress the occurrence of a gloss difference due to the difference in the total toner amount of the toner image.

  According to the invention as set forth in claim 6, the selecting unit applies the transparent toner image to a toner image formed by the first image forming unit, the total toner amount of which is smaller than the largest toner image. The gloss of the toner image having a smaller total toner amount of the toner image can be improved as compared with the case where the toner image is not formed.

  According to the invention as set forth in claim 7, the selection unit is configured to allow the second image forming unit to execute the recording medium in accordance with the number of times of the fixing process that the toner images formed on both sides of the recording medium receive. The gloss difference between the toner images formed on both sides of the recording medium can be reduced as compared with a case where the transparent toner image is not formed on at least one surface of the recording medium.

  According to the invention as set forth in claim 8, the selecting means is a surface of the toner image formed on both surfaces of the recording medium, the surface being opposite to the surface on which the toner image having the largest number of fixing processes is present. The gloss of the toner image on the surface on which the number of times of the fixing process is small can be improved as compared with the case where the toner image is not selected.

  According to the invention as set forth in claim 9, the selecting unit is configured to perform the first and second image forming units as compared with a case where the transparent toner image is not formed on an arbitrary layer among the toner images on the recording medium. A transparent toner image can be formed regardless of the image forming order.

  According to the tenth aspect of the present invention, the first image forming unit and the second image forming unit are different from each other in the case where the first image forming unit and the second image forming unit are not configured by different image forming apparatuses each including the fixing unit. Even if a toner image cannot be formed on a recording medium by the same image forming apparatus due to a color relationship, it is possible to suppress the occurrence of a gloss difference in an image on the same recording medium.

1 is a schematic configuration diagram illustrating an image forming system according to Embodiment 1 of the present invention. FIG. 1 is a configuration diagram illustrating a color image forming apparatus of an image forming system according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram illustrating an image forming unit of the color image forming apparatus. 1 is a configuration diagram illustrating a special color image forming apparatus of an image forming system according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram illustrating an image forming unit of the special color image forming apparatus. FIG. 3 is a schematic diagram illustrating a toner image formed on a recording sheet. 5 is a graph showing a gloss level of a toner image formed on a recording sheet. 5 is a graph showing a gloss level of a toner image formed on a recording sheet. FIG. 2 is a block diagram illustrating a server device of the image forming system according to the first embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a toner image formed on a recording sheet in the image forming system according to the first embodiment of the present invention. 5 is a graph showing a gloss level of a toner image formed on a recording sheet. FIG. 9 is a schematic diagram illustrating a toner image formed on a recording sheet in the image forming system according to Embodiment 2 of the present invention. 9 is a graph showing the glossiness of a toner image formed on recording paper in a conventional example. 9 is a graph illustrating the glossiness of a toner image formed on a recording sheet according to the second embodiment. FIG. 9 is a schematic diagram illustrating a toner image formed on a recording sheet in the image forming system according to Embodiment 3 of the present invention. FIG. 9 is a schematic diagram illustrating a toner image formed on recording paper in a conventional example. FIG. 14 is a schematic diagram illustrating a toner image formed on a recording sheet in the image forming system according to Embodiment 4 of the present invention. FIG. 14 is a configuration diagram illustrating an image forming apparatus according to a fifth embodiment.

  An embodiment of the present invention will be described below with reference to the drawings.

[Embodiment 1]
1 to 5 show the image forming system according to the first embodiment. 1 shows an outline of the whole image forming system, FIG. 2 shows an outline of the whole color image forming apparatus, and FIG. 3 shows an enlarged part (image forming apparatus and the like) of the color image forming apparatus. 4 shows an outline of the entire spot color image forming apparatus, and FIG. 5 shows an enlarged part (image forming apparatus and the like) of the spot color image forming apparatus.

<Configuration of Image Forming System>
The image forming system 1 includes, as shown in FIG. 1, a color image forming apparatus 2 that forms an image using yellow (Y), magenta (M), cyan (C), and black (K) color toners. A special color image forming apparatus 3 that forms an image using a special color toner such as white, metal such as gold or silver, or a custom color toner and a transparent toner, and a server that controls the color image forming apparatus 2 and the special color image forming apparatus 3 Device 4. The color image forming apparatus 2, the special color image forming apparatus 3, and the server apparatus 4 are connected to each other via a communication line 6 so as to be able to communicate with each other. The communication line 6 includes a LAN (local area network), a telephone line, the Internet, and the like.

  Here, the custom color refers to a color created as a single color other than yellow (Y), magenta (M), cyan (C), and black (K). Custom colors include pastel colors such as orange, green, or blue. These custom colors may be adjusted by mixing a plurality of white or other toners in addition to yellow (Y), magenta (M), and cyan (C), and may be colored orange, green, or blue with a pigment. Or a single toner.

  The image forming system 1 forms an image on a recording sheet 5 as an example of a recording medium by the color image forming apparatus 2, sets the recording sheet 5 on the special color image forming apparatus 3, The image forming apparatus 2 is used to form an image having a special color such as white, a metal color such as gold or silver, or a custom color that cannot be formed by the image forming apparatus 2.

<Configuration of Color Image Forming Apparatus>
The color image forming apparatus 2 according to the first embodiment is configured as, for example, a color printer. As shown in FIG. 2, the color image forming apparatus 2 includes a plurality of image forming apparatuses 10 as an example of a first image forming unit that forms a toner image that is developed with a toner constituting a developer. An intermediate transfer device 20 that holds the toner images formed by the image device 10 and conveys the toner image to a secondary transfer position T2 where the toner image is finally secondarily transferred onto the recording paper 5 and a secondary transfer position T2 of the intermediate transfer device 20 A paper feeding device 50 that accommodates and transports the required recording paper 5 to be supplied, a fixing device 40 as an example of a fixing unit that fixes the toner image on the recording paper 5 secondary-transferred by the intermediate transfer device 20, and the like It has. In FIG. 2, reference numeral 2a indicates an apparatus main body of the color image forming apparatus 2, and the apparatus main body 2a is formed of a support structure member, an exterior cover, and the like. A broken line in the drawing indicates a main transport path through which the recording paper 5 is transported inside the apparatus main body 2a.

  The image forming apparatus 10 includes four image forming apparatuses 10Y, 10M, 10C, and 10K that respectively form four color toner images of yellow (Y), magenta (M), cyan (C), and black (K). It is composed of These four image forming apparatuses 10 (Y, M, C, K) are arranged in a line along the horizontal direction in the internal space of the apparatus main body 2a.

  Each of the image forming apparatuses 10 (Y, M, C, and K) includes a photosensitive drum 11 as an example of a rotating image holding unit, as shown in FIGS. 2 and 3. The following devices are mainly arranged around the device. The main devices include a charging device 12 that charges a peripheral surface (image holding surface) of the photoconductor drum 11 on which an image can be formed to a required potential, and image information ( An exposure device 13 as an example of an exposure unit that forms an electrostatic latent image (for each color) having a potential difference by irradiating light based on the signal (i.e., signal) with the corresponding color (Y, M, C). , K), and a primary transfer unit for transferring each toner image to the intermediate transfer unit 20 as a developing unit 14 (Y, M, C, K) as an example of a developing unit that develops with the toner of the developer. There are a primary transfer device 15 as an example of the unit, and a drum cleaning device 16 for removing and cleaning attached matter such as toner remaining on the image holding surface of the photosensitive drum 11 after the primary transfer.

  The photoconductor drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on a peripheral surface of a cylindrical or columnar base material to be grounded. The photosensitive drum 11 is supported so that power is transmitted from a driving device (not shown) and the photosensitive drum 11 rotates in a direction indicated by an arrow A.

  The charging device 12 is configured by a non-contact type charging device such as a corona discharger arranged in a state where the charging device 12 does not contact the photosensitive drum 11. The charging device 12 is supplied with a charging voltage. When the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied as the charging voltage. In addition, as the charging device 12, a contact-type charging device such as a charging roll disposed in contact with the photosensitive drum 11 may be used.

  The exposure device 13 irradiates the peripheral surface of the charged photosensitive drum 11 with a laser beam LB configured according to information of an image input to the color image forming device 2 to form an electrostatic latent image. Is formed. The image information (signal) input from the server device 4 or the like to the color image forming device 2 is transmitted to the exposure device 13 at the time of image formation. In addition, as the exposure device 13, an LED print head that forms an electrostatic latent image by irradiating the photosensitive drum 11 with light by a plurality of LEDs as light emitting elements arranged along the axial direction of the photosensitive drum 11 is used. May be used.

  As shown in FIG. 3, each of the developing devices 14 (Y, M, C, and K) holds the developer 145 inside a housing 140 in which an opening and a chamber for storing the developer 145 are formed. Developing roller 141 that transports the developer 145 to a developing area facing the photosensitive drum 11, stirring and transport members 142 and 143 such as a screw auger that transports the developing agent 145 while passing the developing roller 141 while agitating the developer 145, and holding the developing roller 141. A layer thickness regulating member 144 for regulating the amount (layer thickness) of the developer to be applied is arranged. A developing voltage is supplied to the developing device 14 between the developing roll 141 and the photosensitive drum 11 from a power supply device (not shown). The developing roll 141 and the stirring / conveying members 142 and 143 are rotated in a required direction by transmitting power from a driving device (not shown). Further, a two-component developer containing a non-magnetic toner and a magnetic carrier is used as the developer 145 (Y, M, C, K) of the four colors.

  As shown in FIGS. 2 and 3, the primary transfer device 15 rotates while contacting the peripheral surface of the photosensitive drum 11 via the intermediate transfer belt 21 at the primary transfer position T1, and is supplied with the primary transfer voltage. This is a contact-type transfer device provided with a primary transfer roll. As the primary transfer voltage, a DC voltage indicating a polarity opposite to the charging polarity of the toner is supplied from a power supply device (not shown).

  As shown in FIG. 3, the drum cleaning device 16 is disposed inside the container-like main body 160 and removes and removes extraneous matter such as residual toner. A cleaning brush 162 for cleaning, and a delivery member 163 such as a screw auger that conveys the attached matter such as the toner removed by the cleaning plate 161 and the cleaning brush 162 and sends it to a collection system (not shown) are provided. As the cleaning plate 161, a plate-like member (for example, a blade) made of a material such as rubber is used.

  As shown in FIG. 2, the intermediate transfer device 20 is disposed at a position below each image forming device 10 (Y, M, C, K). The intermediate transfer device 20 is an intermediate transfer device as an example of an intermediate transfer unit that circulates and moves in a direction indicated by an arrow B while passing through a primary transfer position T1 between the photosensitive drum 11 and a primary transfer device 15 (primary transfer roll). A transfer belt 21, a plurality of belt support rolls 22 to 27 for holding the intermediate transfer belt 21 in a desired state from its inner periphery and supporting the intermediate transfer belt 21 to be able to circulate; and an intermediate supporter supported by the belt support roll 26. A secondary transfer device 30 disposed on the outer peripheral surface (image holding surface) side of the transfer belt 21 for secondary transfer of the toner image on the intermediate transfer belt 21 to the recording paper 5; It mainly includes a belt cleaning device 28 that removes and cleans extraneous matters such as toner and paper dust remaining on the outer peripheral surface of the transfer belt 21.

  As the intermediate transfer belt 21, an endless belt made of a material in which a resistance adjuster such as carbon black is dispersed in a synthetic resin such as a polyimide resin or a polyamide resin is used. Further, the belt support roll 22 is configured as a drive roll, the belt support rolls 23 and 25 are configured as driven rolls that hold the traveling position of the intermediate transfer belt 21, and the like, the belt support roll 24 is configured as a tension applying roll, The support roll 26 is configured as a backup roll for secondary transfer, and the belt support roll 27 is configured as a support roll for the belt cleaning device 28.

  As shown in FIG. 2, the secondary transfer device 30 contacts and rotates at a secondary transfer position T2 which is an outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 26 in the intermediate transfer device 20. A contact-type transfer device having a secondary transfer roll 31 arranged as described above is employed. The secondary transfer roll 31 is grounded. The belt support roll 26 is supplied with a required secondary transfer bias having the same negative polarity as the charged polarity of the toner from a high-voltage power supply (not shown) via a bias application roll 29.

  The fixing device 40 includes, as shown in FIG. 2, a heating rotator 41 in the form of a roll or a belt heated by a heating unit (heat source) (not shown) so that the surface temperature is maintained at a predetermined temperature. A roller-type or belt-type pressurizing rotator 42 that rotates by contacting the heating rotator 41 with a predetermined pressure is arranged. In the fixing device 40, a contact portion where the heating rotator 41 and the pressing rotator 42 come into contact is a fixing processing unit that performs required fixing processing (heating and pressing).

  The paper feeding device 50 is arranged so as to exist at a position below the intermediate transfer device 20. The paper feeding device 50 includes a single (or plural) paper container 51 for accommodating the recording paper 5 of a desired size, type, and the like in a stacked state, and sending out the recording paper 5 one by one from the paper container 51. It mainly comprises the device 52. The paper container 51 is attached so that it can be pulled out, for example, to the front side (side surface facing the user during operation) of the apparatus main body 2a.

  The recording paper 5 is, for example, a thin paper such as a plain paper or a tracing paper used in an electrophotographic copying machine or a printer, or an OHP sheet made of a transparent film-like medium made of a synthetic resin (PET or the like). And the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing, etc. So-called cardboard having a relatively large basis weight can also be suitably used.

  The type of the recording sheet 5 supplied from the sheet container 51 is selected by the operation unit of the server device 4 or the color image forming apparatus 2 which instructs the image forming operation, or is provided on the sheet container 51 (not shown). It is determined by the detecting means. The detecting means does not need to directly detect the type of the recording paper 5, but outputs a signal corresponding to the type of the recording paper 5 stored in the paper storage body 51 to a control device 100 described later. I just want it.

  Between the sheet feeding device 50 and the secondary transfer device 30, a plurality (or a single) pair of sheet transport rolls 53 to 56 for transporting the recording sheet 5 sent from the sheet feeding device 50 to the secondary transfer position T2 are shown in FIG. There is provided a paper feed path 57 made of a non-conveyance guide material. The paper transport roll pair 56 disposed at a position immediately before the secondary transfer position T2 in the paper transport path 57 is configured, for example, as a roll (registration roll) that adjusts the transport timing of the recording paper 5.

  Further, between the secondary transfer device 30 and the fixing device 40, a plurality (or a single) sheet transport belts 58, 59, and 60 for transporting the recording paper 5 sent from the secondary transfer device 30 to the fixing device 40 are provided. The paper transport path 61 is provided.

  On the downstream side of the fixing device 40, a sheet provided with a sheet discharge roll 63 for discharging the recording sheet 5 on which the toner image has been fixed by the fixing device 40 to a sheet discharge portion 62 arranged on a side surface of the apparatus main body 2a. A discharge conveyance path 64 is provided.

  A reversing conveyance path 65 for reversing the front and back of the recording paper 5 is branched downward in the middle of the sheet discharge conveyance path 64. A switching member (not shown) that switches the transport direction of the recording paper 5 is provided at a branch position of the paper discharge transport path 64. In the reversing conveyance path 65, a reversing roll pair 66 capable of switching the rotation direction between the normal rotation direction and the reverse rotation direction is disposed. The reversing conveyance path 65 is connected to a two-sided conveyance path 67 branched from the upper part of the reversing roll pair 66 to the left side in the figure. In the double-sided conveyance path 67, a plurality of double-sided conveyance roll pairs 68 to 71 for conveying the recording paper 5 with the front and back reversed to the paper supply conveyance path 57 and a conveyance guide material (not shown) are arranged.

  In FIG. 2, reference numeral 100 denotes a control device as an example of a control unit that comprehensively controls the operation of the color image forming apparatus 2. The control device 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a bus connecting these CPUs and the ROM, and a communication interface (not shown). The control device 100 controls the operation of the color image forming device 2 based on a control signal output from the server device 4.

<Basic operation of color image forming apparatus>
Hereinafter, a basic image forming operation by the color image forming apparatus 2 will be described.

  Here, when forming a color image formed by combining the toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K). The image forming operation will be described.

  When the color image forming apparatus 2 receives command information of an image forming operation (print) request from the server apparatus 4, the four image forming apparatuses 10 (Y, M, C, K) and the intermediate The transfer device 20, the secondary transfer device 30, the fixing device 40, and the like start.

  Then, in each of the image forming apparatuses 10 (Y, M, C, and K), first, each photoconductor drum 11 rotates in the direction indicated by the arrow A, and each charging device 12 moves the surface of each photoconductor drum 11 to a required position. It is charged to a polarity (minus polarity in the first embodiment) and a potential. Subsequently, the exposure device 13 converts the information of the image input to the color image forming device 2 into each color component (Y, M, C, K) on the charged surface of the photoconductor drum 11 and is obtained. Light emitted based on an image signal is irradiated, and an electrostatic latent image of each color component having a required potential difference is formed on the surface thereof. The control device 100 sends to the server device 4 an image signal obtained by converting the information of the image input to the color image forming device 2 into each color component (Y, M, C, K).

  Subsequently, each of the developing devices 14 (Y, M, C, and K) applies a corresponding color (negative polarity) to the electrostatic latent image of each color component formed on the photosensitive drum 11 with a corresponding polarity (negative polarity). The toners of (Y, M, C, K) are supplied and electrostatically adhered to each other for development. As a result of this development, the electrostatic latent images of the respective color components formed on the respective photosensitive drums 11 are visualized as toner images of four colors (Y, M, C, K) respectively developed with the corresponding color toners. Be transformed into

  Subsequently, when the toner image of each color formed on the photosensitive drum 11 of each image forming device 10 (Y, M, C, K) is conveyed to the primary transfer position T1, the primary transfer device 15 causes each color to be transferred. Is primarily transferred onto the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20 in a state where the toner images are sequentially superimposed.

  In each of the image forming apparatuses 10 after the primary transfer, the drum cleaning device 16 removes the attached matter so as to scrape off and cleans the surface of the photosensitive drum 11. Thereby, each image forming apparatus 10 is set to a state where the next image forming operation can be performed.

  Subsequently, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and transported to the secondary transfer position T2. On the other hand, the paper feeder 50 sends out the required recording paper 5 to the paper feed path 57 in accordance with the image forming operation. In the sheet feeding path 57, a sheet conveying roll pair 56 as a registration roll feeds and supplies the recording sheet 5 to the secondary transfer position T2 according to the transfer timing.

  At the secondary transfer position T2, the secondary transfer roll 31 causes the toner image on the intermediate transfer belt 21 to be secondary-transferred onto the recording paper 5 at one time. Further, in the intermediate transfer device 20 after the completion of the secondary transfer, the belt cleaning device 28 removes and removes adhered matter such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

  Subsequently, the recording paper 5 on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 21 and the secondary transfer roll 31, and then is conveyed to the fixing device 40 by three conveyer belts 58, 59, and 60. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced and passed through a fixing processing section between the rotating heating rotator 41 and the pressing rotator 42, thereby performing necessary fixing processing (heating and heating). Pressure) to fix the unfixed toner image on the recording paper 5.

  The recording paper 5 holding the unfixed toner image passes through the contact portion between the rotating heating rotator 41 and the pressing rotator 42 each time the recording paper 5 passes through the fixing device 40 such as when forming a two-sided image. Then, a fixing process involving heat and pressure is applied.

  After the fixing process is completed, the recording paper 5 is discharged to a discharge accommodating portion 62 provided on a side surface of the color image forming apparatus 2 by a paper discharge roll 63 via a paper discharge conveyance path 64.

  In the case where images are formed on both sides of the recording paper 5 in the color image forming apparatus 2, the recording paper 5 having the image formed on one side is not discharged to the discharge accommodating portion 62 by the paper discharge roll 63, and is not shown. The transport path of the recording paper 5 is switched from the paper discharge transport path 64 to the reverse transport path 65 by the switching member. With the recording paper 5 guided to the reverse conveyance path 65, the rotation direction of the reversing roll pair 66 is switched from the normal rotation direction to the reverse rotation direction with the reversing roll pair 66 holding the rear end of the recording paper 5 therebetween. The sheet is conveyed to the double-sided conveying path 67 with the front and back reversed. The recording sheet 5 conveyed to the double-sided conveyance path 67 is conveyed to the sheet conveyance path 57 by a plurality of sheet conveyance roll pairs 68 to 71, and the toner image is transferred from the intermediate transfer belt 21 to the back surface. Thereafter, the recording paper 5 is conveyed to the fixing device 40, subjected to a fixing process (heating and pressurization) by the fixing device 40, and is passed through the paper discharge conveyance path 64 to the discharge storage section 62 by the paper discharge roll 63. Is discharged.

  By performing the above operation, a color image formed by combining toner images of four colors of toner T (Y, M, C, K) is formed on one side or both sides of the recording paper 5. When a request command for a plurality of image forming operations is received, the image forming operation is repeated by the number of sheets in the same manner. As described above, in addition to the color image, an image in which one to three color toner images are appropriately combined by forming a toner image in one to three image forming apparatuses can be formed on a recording paper by the same image forming operation. 5 is formed.

<Structure of special color image forming apparatus>
FIG. 4 is a configuration diagram showing the special color image forming apparatus 3 of the image forming system 1 according to Embodiment 1 of the present invention.

  The spot color image forming apparatus 3 according to the first embodiment is configured as, for example, a spot color printer. As shown in FIG. 4, the special color image forming apparatus 3 is basically configured in the same manner as the color image forming apparatus 2 except that the color of the toner image to be formed is different. And the description is omitted. The spot color image forming apparatus 3 includes four image forming apparatuses 10 that form toner images of different colors.

  The four image forming apparatuses 10 are roughly classified into an image forming apparatus 10CT as an example of a second image forming unit that forms a transparent toner image developed with transparent toner (CT), and developed with toner other than the transparent toner. The image forming apparatus includes three image forming apparatuses 10 as an example of a first image forming unit that forms a toner image. These four image forming apparatuses 10 are arranged in a line along the horizontal direction in the internal space of the apparatus main body 3a. The image forming apparatus 10CT that forms a transparent toner image is disposed at the most upstream side along the moving direction B of the intermediate transfer belt 21.

  In this embodiment, as the three image forming apparatuses 10, an image forming apparatus 10CU that forms a toner image to be developed with a custom color (CU) toner, and a silver color toner (SI) as an example of a metal color An image forming apparatus 10SI for forming a toner image and an image forming apparatus 10W for forming a white toner image developed with white toner (W) are used.

  Each image forming apparatus 10 (CT, CU, SI, W) is configured similarly to each image forming apparatus (Y, M, C, K) of the color image forming apparatus 2 as shown in FIG. .

  The transparent toner image forming apparatus 10CT includes a toner other than the transparent toner formed on the same recording sheet 5 by the special color image forming apparatus 3, including the toner image formed on the recording sheet 5 by the color image forming apparatus 2 described above. The transparent toner image is formed so as to overlap at least a part of the image.

  The control device 100 of the special color image forming apparatus 3 includes, in addition to the information on the image formed by the special color image forming apparatus 3 from the server apparatus 4, toners T (Y, M) of four colors formed by the color image forming apparatus 2. , C, K) is also input.

  Among them, the exposure device 13 of the transparent toner image forming device 10CT in the special color image forming apparatus 3 has information on image information of toner images other than the transparent toner on which the transparent toner image is superimposed, that is, yellow (Y) and magenta (M). , Cyan (C) and black (K) toner images of four colors T (Y, M, C, K) and custom color (CU), silver toner (SI), white toner (W) The image information of the toner image composed of the three color (type) toners is input as appropriate.

  The exposure device 13 of the transparent toner image forming device 10CT emits the laser beam LB configured according to image information of a toner image other than the transparent toner on which the transparent toner image is superimposed, and the charged photosensitive drum 11 Irradiation is performed on the peripheral surface to form an electrostatic latent image. Subsequently, the transparent toner developing device 14 supplies the transparent toner charged to a required polarity (minus polarity) to the electrostatic latent image formed on the photoconductor drum 11 and causes the electrostatic latent image to electrostatically adhere. Perform development. By this development, the electrostatic latent image formed on the photosensitive drum 11 is visualized as a transparent toner image developed with the transparent toner.

  In this embodiment, as shown in FIG. 4, the image forming apparatus 10CT for the transparent toner is arranged at the most upstream side along the moving direction of the intermediate transfer belt 21 as described above. The transparent toner image formed by the transparent toner image forming device 10CT is formed as a first layer on the intermediate transfer belt 21, and is formed in a state where it is superimposed on the surface of another special color toner image as necessary. You.

  The transparent toner image formed as the first layer on the intermediate transfer belt 21 has the yellow (Y), magenta (M), and cyan (C) already formed on the recording paper 5 at the secondary transfer position T2. And a color toner image such as black (K) is superimposed and secondary-transferred as necessary.

  The spot color image forming apparatus 3 includes a fixing device 40 as an example of a fixing unit, like the color image forming apparatus 2. As shown in FIG. 4, the fixing device 40 includes a heating rotator 41 in the form of a roll or a belt heated by a heating unit (heat source) (not shown) so that the surface temperature is maintained at a predetermined temperature. A roller-type or belt-type pressurizing rotator 42 that rotates by contacting the heating rotator 41 with a predetermined pressure is arranged. In the fixing device 40, a contact portion where the heating rotator 41 and the pressing rotator 42 come into contact is a fixing processing unit that performs required fixing processing (heating and pressing).

  In the fixing device 40, not only the unfixed toner image formed by the special color image forming device 3 but also the toner image already formed on the recording paper 5 by the color image forming device 2 pass through the fixing device 40. Receives the fixing process. That is, when the toner image formed on the recording paper 5 by the color image forming apparatus 2 is subjected to required fixing processing (heating and pressing) by the fixing apparatus 40, At the same time, the sheet passes through the fixing device 40 of the special color image forming apparatus 3 to receive necessary fixing processing (heating and pressurizing) repeatedly.

  As shown in FIG. 4, the spot color image forming apparatus 3 includes an external sheet feeding device 80 on the left side of the apparatus main body 3a. Similarly to the paper feeding device 50, the external paper feeding device 80 includes a single (or plural) paper housing 81 that stores the recording paper 5 of a desired size, type, and the like in a stacked state, and records from the paper housing 81. It mainly comprises a sending device 82 for sending out the sheets 5 one by one.

  The external paper feeder 80 can feed the recording paper 5 other than the paper supplied from the paper feeder 50, and the single-sided color image forming apparatus 2 as an example of another image forming apparatus. Alternatively, the recording sheet 5 on which images are already formed on both sides is accommodated in the sheet container 81, and the recording sheet 5 on which an image is already formed is sent out from the sheet container 81 by the sending device 82 and supplied one by one. It has become possible.

  The external paper feeding device 80 is connected to the paper feeding conveyance path 57 via the auxiliary paper feeding conveyance path 83. The recording paper 5 supplied from the external paper feeding device 80 is transferred to the secondary transfer position T2 of the intermediate transfer device 20 by a pair of paper transport rolls 55 and 56 arranged on the paper transport route 57 via the auxiliary paper transport route 83. Transported to

<Basic operation of special color image forming apparatus>
The image forming operation of the special color image forming apparatus 3 is basically the same as that of the color image forming apparatus 2.

  The special color image forming apparatus 3 performs an image forming operation from the server apparatus 4 in a state where the recording sheet 5 on which an image is already formed on one side or both sides by the color image forming apparatus 2 is stored in the paper container 81 of the external paper feeding apparatus 80. When the control device 100 of the special color image forming apparatus 3 receives the command information of the request for the image forming operation (print), the four image forming apparatuses are controlled by the control device 100. 10 (CT, CU, SI, W), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, etc. are started.

  Then, at least one or more of the transparent toner (W), the custom color (CU) toner, the silver (SI) toner, and the white (W) toner image forming apparatus 10 (CT, CU, SI, W) In this image forming apparatus, toner images of the corresponding colors are formed.

  Subsequently, when the color toner image formed on the photosensitive drum 11 of the image forming device 10 (CT, CU, SI, W) is conveyed to the primary transfer position T1, the primary transfer device 15 causes The toner image is primarily transferred to the intermediate transfer belt 21 of the intermediate transfer device 20 rotating in the direction indicated by the arrow B.

  Subsequently, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and transported to the secondary transfer position T2. On the other hand, the paper feeder 50 sends out the required recording paper 5 to the paper feed path 57 in accordance with the image forming operation. In the sheet feeding path 57, a sheet conveying roll pair 56 as a registration roll feeds and supplies the recording sheet 5 to the secondary transfer position T2 according to the transfer timing.

  Further, the external paper feeding device 80 in this embodiment selectively operates with the paper feeding device 50 to feed the recording paper 5 stored in the paper storage body 81 in the auxiliary paper feeding path 83 in accordance with the image forming operation. Through the paper feed path 57. In the sheet feeding path 57, a sheet conveying roll pair 56 as a registration roll feeds and supplies the recording sheet 5 to the secondary transfer position T2 according to the transfer timing.

  At the secondary transfer position T2, the secondary transfer roll 31 causes the toner image on the intermediate transfer belt 21 to be secondary-transferred onto the recording paper 5 at one time. Further, in the intermediate transfer device 20 after the completion of the secondary transfer, the belt cleaning device 28 removes and removes extraneous matter such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

  Subsequently, the recording paper 5 on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 21 and the secondary transfer roll 31, and then is conveyed to the fixing device 40 by three conveyer belts 58, 59, and 60. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced and passed through a contact portion between the rotating heating rotator 41 and the pressing rotator 42, so that a necessary fixing process (heating and heating) is performed. Pressure) to fix the unfixed toner image on the recording paper 5.

  After the fixing process is completed, the recording paper 5 is discharged to a discharge accommodating portion 62 provided on a side surface of the spot color image forming apparatus 3 by a paper discharge roll 63 via a paper discharge conveyance path 64.

  When forming an image on both sides of the recording paper 5 in the special color image forming apparatus 3, the recording paper 5 on which an image is formed on one side is not discharged to the discharge accommodating portion 62, but is discharged by a switching member (not shown). By switching the transport path from the transport path 64 to the reverse transport path 65, images are formed on both sides of the recording paper 5.

  By performing the above operation, the transparent toner (W) and the custom color are formed on one or both sides of the recording paper 5 on which the color toner image composed of the four color toners T1 (Y, M, C, K) is formed. A toner image composed of at least one special color toner T (CT, CU, SI, W) of (CU) toner, silver (SI) toner, and white (W) toner is formed. When a request command for a plurality of image forming operations is received, the image forming operation is repeated by the number of sheets in the same manner.

  In the image forming system 1, as shown in FIGS. 6A and 6B, for example, in the color image forming apparatus 2, a cyan toner image 501C is formed on a first surface (front surface) 5a of the recording paper 5. After forming and fixing the cyan toner image 501C to the first surface 5a of the recording paper 5 by the fixing device 40, a cyan toner image 502C is also formed on the second surface (back surface) 5b of the recording paper 5. In some cases, the cyan toner image 502 </ b> C is subjected to a fixing process on the second surface 5 b of the recording paper 5 by the fixing device 40.

  Thereafter, in the image forming system 1, as shown in FIG. 4, the recording sheet 5 on which the cyan toner images 501C and 502C are formed on the first surface (front surface) 5a and the second surface by the color image forming apparatus 2 is formed. 6 (c), a custom color toner image 503CU is formed on the first surface 5a of the recording paper 5 in the special color image forming apparatus 3. As shown in FIG. In some cases, the custom color toner image 503CU is subjected to a fixing process on the first surface 5a of the recording paper 5 by the fixing device 40 to form an image.

  Then, of the toner images formed on the recording paper 5, the cyan toner image 501 </ b> C formed on the first surface 5 a of the recording paper 5 undergoes two fixing processes by the fixing device 40 of the color image forming apparatus 2. Thereafter, the fixing device 40 of the spot color image forming apparatus 3 receives one fixing process, and receives a total of three fixing processes.

  On the other hand, among the toner images formed on the recording paper 5, the cyan toner image 502 </ b> C formed on the second surface 5 b of the recording paper 5 undergoes one fixing process by the fixing device 40 of the color image forming apparatus 2. Thereafter, the fixing device 40 of the spot color image forming apparatus 3 receives one fixing process, and receives a total of two fixing processes.

  Further, among the toner images formed on the recording paper 5, the custom color toner image 503 CU formed on the first surface 5 a of the recording paper 5 is subjected to the fixing process only once by the fixing device 40 of the special color image forming apparatus 3. receive.

  As described above, in the image forming system 1, one of the cyan toner images 501 </ b> C among the toner images formed on the first surface 5 a, which is the same surface of the recording paper 5, is subjected to the fixing process three times in total. On the other hand, the other custom color toner image 503CU is subjected to the fixing process only once.

  When the toner image fixed on the recording sheet 5 undergoes a required fixing process (heating and pressing) from the heating rotator 41 and the pressing rotator 42 of the fixing device 40, the toner is heated and melted, The melted toner is fixed on the recording paper 5 by a pressing action. Therefore, in the toner image fixed on the recording paper 5, as the number of fixing processes received by the fixing device 40 increases, the degree of melting of the toner increases, and at the same time, the smoothing of the surface is promoted and the gloss tends to increase. .

  As a result, in the above-described example, as shown in FIG. 7, the glossiness of the cyan toner image 501 </ b> C that is subjected to the fixing process by the fixing device 40 three times in total is as high as about 40, but only once. The glossiness of the custom color toner image 503CU, which is only subjected to the fixing process, is greatly reduced to about 20, and a gloss difference occurs between the images formed on the first surface 5a which is the same surface of the recording paper 5. The gloss difference between the images on the same surface of the recording paper 5 is visually recognized by the user as unevenness in the gloss of the image formed on the recording paper 5, and thus causes a reduction in image quality. The glossiness is a value measured when reflected light is measured at an angle of 60 degrees with respect to the surface of the recording paper 5.

  FIG. 8 shows a cyan monochromatic toner image having a density of 100%, a magenta color cyan image having a density of 100%, and a blue toner image having a cyan color having a density of 100%. A toner image in the case where a process black toner image composed of a magenta color and a cyan triple color is fixed to the recording paper 5 by the fixing device 40, and the number of fixing processes is changed from once to four times 5 is a graph showing the measured glossiness of the sample.

  As apparent from FIG. 8, the cyan toner image, which is a single-layer toner image, has a small amount of toner and has a glossiness of about 20 when subjected to a single fixing process, and is compared with other toner images. And show significantly lower values. In addition, the glossiness of a single-layer cyan toner image sharply increases as the number of times of fixing processing increases to twice and three times, and reaches about 43 after four times of fixing processing. Ascend and converge.

  Further, the amount of toner of the blue toner image composed of the dual colors of magenta and cyan is twice as large as that of the single-layer cyan toner image, and the toner image is subjected to one fixing process. However, the glossiness shows a high value of about 38, and the glossiness gradually increases as the number of times of the fixing process increases to twice and three times. Converge.

  On the other hand, the process black toner image composed of the three colors of yellow, magenta and cyan has a larger toner amount than the blue toner image composed of the dual colors of magenta and cyan. Even when the fixing process is performed a number of times, the glossiness shows a high value of about 43. Even if the number of the fixing processes increases to twice and three times, the glossiness slightly increases but only four times. The value of about 47, which is substantially the same as the value of the fixing process performed three times, is shown in FIG.

  As can be understood from FIG. 8, the number of times of fixing the toner image fixed on the same recording paper 5 and the amount of toner forming the toner image, that is, the total amount of toner overlapping the same portion of the recording paper 5 where the toner is formed. It can be seen that there is a large difference in gloss depending on the amount of toner.

  Therefore, in the image forming system 1 according to the first embodiment, the transparent toner image is formed by the transparent toner image forming apparatus 10CT of the special color image forming apparatus 3 in accordance with the number of times of the fixing process that the toner image on the recording paper 5 receives. And a server device 4 having a function as a selection unit for selecting a toner image on the recording paper 5 formed by superimposing the toner images. That is, the server device 4 having a function as a selection unit is a device for forming a transparent toner image of the special color image forming device 3 for a toner image having a low gloss level among toner images formed on the recording paper 5. This is to select a toner image so as to form a transparent toner image by superimposing in 10CT. When the toner image made of the transparent toner is formed on the uppermost layer of the toner image formed on the recording paper 5, the toner image itself made of the transparent toner has gloss, and increases the glossiness of the toner image. Further, even when the toner image composed of the transparent toner is formed on the intermediate layer or the lowermost layer of the toner image formed on the recording paper 5, the toner image composed of the transparent toner is the total toner of the other toner images. The amount is increased, and consequently the glossiness of the toner image is increased.

  FIG. 9 is a block diagram showing the server device 4 in the image forming system 1 according to the first embodiment.

  As shown in FIG. 9, the server device 4 includes a control unit 401, a storage unit 402, an operation unit 403, and a communication unit 404.

  The control unit 401 has a CPU 401a and a RAM 401b. The control unit 401 executes a gloss control program stored in the storage unit 402, controls the storage unit 402, the operation unit 403, or the communication unit 404, and controls the color image forming apparatus 2 and the communication unit 404 via the communication unit 404. The special color image forming apparatus 3 is controlled.

  Further, as described above, the control unit 401 functions as a selection unit that selects the toner image on the recording paper 5 on which the transparent toner image forming apparatus 10CT of the special color image forming apparatus 3 forms the transparent toner image by superimposing. It has. In addition, the function as the selection unit realized by the control unit 401 includes not only the selection of the toner image on the recording paper 5 on which the transparent toner image forming apparatus 10CT forms the transparent toner image but also the It also has a function of adjusting the density and the like of the transparent toner image to be combined.

  The control unit 401 controls the image forming operation in the color image forming apparatus 2 and the special color image forming apparatus 3 and fixes the toner image formed on the same recording paper 5 to the color image forming apparatus 2 and the special color image forming apparatus 3. It has a function as a counting means for counting the number of fixing processes received by the device 40.

  In the color image forming apparatus 2 and the special color image forming apparatus 3, as shown in FIGS. 2 and 4, after the toner image is secondarily transferred from the intermediate transfer belt 21 to the recording paper 5, the toner image always passes through the fixing device 40. Then, the fixing device 40 receives a fixing process. Therefore, the number of times the toner image formed on the recording sheet 5 undergoes the fixing process can be obtained by counting the number of times the toner image has been transferred onto the recording sheet 5. When the transfer of the toner image to the recording sheet 5 is performed twice, the toner image firstly (first) transferred to the recording sheet 5 undergoes the fixing process twice, and is transferred to the recording sheet 5 for the second time. The toner image undergoes one fixing process.

  The control unit 401 calculates the number of times of the fixing process that the toner image finally formed on the recording paper 5 receives in each of the color image forming apparatus 2 and the special color image forming apparatus 3, and basically performs the fixing process. The toner image with the least number of times is selected as the toner image on the recording paper 5 formed by superimposing the transparent toner image.

  In addition, the control unit 401 calculates the number of times of the fixing process that the toner image finally formed on the recording paper 5 receives in both the color image forming apparatus 2 and the special color image forming apparatus 3, and the number of times of the fixing process is the smallest. A configuration may be adopted in which a toner image other than the large number of toner images is selected as a toner image on the recording paper 5 formed by superimposing the transparent toner images. In this case, among the toner images other than the toner image having the largest number of fixing processes, the toner amount of the transparent toner image may be changed so as to be inversely proportional to the number of fixing processes.

  The control unit 401 of the server device 4 transmits the image information of the selected toner image to the control device 100 of the special color image forming device 3, and the control device 100 of the special color image forming device 3 needs the image information of the selected toner image. Is output to the image forming apparatus 10CT for the transparent toner image at the timing of (1).

  The operation unit 403 includes an input unit 403a for a user to input necessary setting conditions and the like to the server device 4, a display unit 403b for displaying states of the server device 4, the color image forming apparatus 2, and the special color image forming apparatus 3. ing.

  The communication unit 404 functions as a communication interface for performing data communication, and is connected to the communication line 6.

<Operation of image forming system>
The image forming system 1 according to the first embodiment operates as follows.

  In the image forming system 1 according to the first embodiment, as shown in FIG. 1, a toner image of a required color is formed on one side or both sides of the recording paper 5 in the color image forming apparatus 2 based on the control of the server device 4. Is formed on the same recording sheet 5 in the special color image forming apparatus 3 to form a toner image of a required color including a transparent toner image made of a transparent toner on one or both sides of the recording sheet 5.

  In the color image forming apparatus 2, for example, as shown in FIGS. 10A and 10B, a cyan toner image 511C is formed on the first surface 5a of the recording sheet 5, and the cyan toner image 511C is fixed. After fixing to the first surface 5a of the recording sheet 5 by the device 40, a cyan toner image 512C is similarly formed on the second surface 5b of the recording sheet 5 and the cyan toner image 512C is fixed by the fixing device 40 to the recording sheet. 5, a process of fixing the second surface 5b is performed.

  Next, in the image forming system 1 according to the first embodiment, as shown in FIG. 4, the recording paper on which the cyan toner images 511C and 512C are formed on both sides by the user with the color image forming apparatus 2, respectively. 5 is set on the external paper feeding device 80 of the special color image forming apparatus 3 with the first surface 5a of the recording paper 5 facing up, and the special color image forming apparatus 3 forms a special color toner image and a transparent toner image. .

  For example, in the image forming system 1, since the color image forming apparatus 2 forms a custom color toner image that cannot be formed on the first surface 5 a of the recording paper 5, the recording on which the image is formed by the color image forming apparatus 2 is performed. The sheet 5 is set on the external sheet feeding device 80 of the special color image forming apparatus 3.

  The spot color image forming apparatus 3 forms a custom color toner image 513CU on the first surface 5a of the recording paper 5 based on a signal from the control unit 401 of the server device 4 as shown in FIG. At the same time, a toner image 514CT made of transparent toner is formed so as to overlap the custom color toner image 513CU. The custom color toner image 513CU and the toner image 514CT formed of the transparent toner formed on the first surface 5a of the recording sheet 5 are fixed on the recording sheet 5 by the fixing device 40 of the special color image forming apparatus 3.

  When such an image forming operation is performed, as shown in FIG. 10C, the cyan toner image 511C formed on the first surface 5a of the recording paper 5 is fixed to the fixing device 40 of the color image forming apparatus 2. , The fixing device 40 of the spot color image forming apparatus 3 receives one fixing process, and receives a total of three fixing processes. On the other hand, the custom color toner image 513CU formed on the first surface (front surface) 5a of the recording paper 5 undergoes the fixing process only once in the fixing device 40 of the special color image forming apparatus 3.

  Therefore, when forming the custom color toner image 514CU on the recording sheet 5 in the special color image forming apparatus 3, the control unit 401 of the server apparatus 4 forms the custom color toner image 514CU on the first surface 5a of the recording sheet 5 with the least number of fixing processes. The custom-color toner image 513CU is formed so as to be superimposed on the toner image 514CT made of transparent toner by the transparent toner image forming apparatus 10CT.

  The custom color toner image 513CU formed on the first surface 5a of the recording paper 5 is subjected to fixing processing by the fixing device 40 of the special color image forming apparatus 3 in a state where the toner image 514CT made of transparent toner is superimposed.

  As a result, as shown in FIG. 11, the transparent toner image 514CT of the custom color toner image 513CU formed on the first surface (front surface) 5a of the recording paper 5 is superimposed on the front surface, and the toner amount increases. Glossiness increases. Further, since the transparent toner image 514CT is located on the surface of the custom color toner image 513CU, the glossiness is increased to about 38 by the transparent toner image 514CT itself. Therefore, the custom-color toner image 513CU formed on the first surface 5a of the recording paper 5 is the same as the cyan toner image 511C that has also been formed on the first surface 5a of the recording paper 5 and has undergone three fixing processes. The glossiness becomes a substantially similar value, the glossiness difference between the cyan toner image 511C formed on the first surface 5a of the recording paper 5 and the custom color toner image 513CU is reduced, and the gloss unevenness is suppressed. The image quality will be improved.

  As described above, in the first embodiment, a gloss difference occurs in an image on the same recording paper 5 as compared with a case where a transparent toner image is formed regardless of the number of times of fixing of the toner image on the recording paper 5. Can be suppressed.

  In FIG. 10, for convenience, the cyan toner image 511C formed on the first surface 5a of the recording paper 5 and the cyan toner image 512C formed on the second surface 5b of the recording paper 5 are recorded. Although formed at the same position on the paper 5, the position of the toner image formed on the first surface 5 a of the recording paper 5 and the position of the toner image formed on the second surface 5 b of the recording paper 5 are not arbitrary. Of course.

[Embodiment 2]
FIG. 12 shows an image forming system according to the second embodiment. In the image forming system 1 according to the second embodiment, when the number of toner image fixing processes is the same, the control unit 401 of the server device that functions as a selecting unit transmits the transparent image to be superimposed on the toner image having a small total toner amount. The toner amount of the toner image is configured to be increased.

  In the image forming system 1, for example, as shown in FIGS. 12A and 12B, in the color image forming apparatus 2, the first surface 5 a of the recording paper 5 such as colored paper, metallic paper, and film is yellow and magenta. In addition to forming a red toner image 521R in which the color toner images 521Y and 521M are superimposed, a single-color yellow toner image 521Y is formed at a different position on the first surface 5a of the recording paper 5, and the red color is formed. The toner image 521R and the single-color toner image 521Y of only yellow may be fixed to the first surface 5a of the recording paper 5 by the fixing device 40. Thereafter, in the special color image forming apparatus 3, a white toner image 523W is formed by superimposing the red toner image 521R on the first surface 5a of the recording paper 5 and a silver toner image 524Si is formed at a different position. The fixing process of the white toner image 523W and the silver toner image 524Si may be performed by the fixing device 40 of the special color image forming apparatus 3.

  Then, as shown in FIG. 12B, among the toner images formed on the first surface 5a of the recording sheet 5, the red toner 523R is superimposed with the white toner image 523W on the red toner image 521R. The image has a large amount of toner, whereas the yellow and silver toner images 522Y and 524Si have a single toner layer and a small amount of toner.

  Here, the red toner image obtained by superimposing the white toner image on the yellow and magenta toner images 521Y and 521M receives the fixing process twice, and the yellow toner image 522Y receives the fixing process. The number of times of the processing is also two times, and only the number of times of the fixing processing received by the silver toner image 524Si is one.

  Therefore, looking at the number of times of fixing processing of each toner image, the red toner image in which the white toner image is superimposed on the yellow and magenta toner images 521Y and 521M, and the yellow single color toner image 522Y The number of times of fixing processing received is two times, and there is no difference.

  However, as shown in FIG. 13, the toner amount of the toner image obtained by superimposing the white toner image on the yellow and magenta toner images 521Y and 521M and the yellow toner image 522Y are twice or more as shown in FIG. In contrast, even if the number of times of the fixing process is the same two times, there is a difference in glossiness after fixing.

  Further, the yellow toner image 522Y and the silver toner image 524Si are both composed of a single color toner image, and the number of times of fixing processing is different from twice and once, and the number of times of fixing processing is different only once. However, there is a difference in glossiness after fixing.

  Therefore, in the image forming system 1 according to the second embodiment, as shown in FIG. 12C, the control unit 401 of the server device 4 determines that when the number of toner image fixing processes is the same, the toner amount Is selected so that a transparent toner image is superimposed on a toner image having a small amount. Further, the control unit 401 is configured to increase the toner amount of the transparent toner image with respect to the toner image having the smallest number of toner image fixing processes and the small toner amount.

  In the image forming system 1 according to the second embodiment, as shown in FIG. 12C, a toner image in which a white toner image is superimposed on yellow and magenta toner images 521Y and 521M, and a yellow In the toner image 522Y, the number of times of the fixing process is the same two times, but since the toner amount is twice or more different (less), the transparent toner image having a density of 50% with respect to the yellow toner image 522Y. 525CT is formed by overlapping.

  Further, in the image forming system 1 according to the second embodiment, since the number of times of the fixing process is different between the yellow toner image 522Y and the silver toner image 524Si twice and one time, the silver toner image 524Si is different from the yellow toner image 524Si. The transparent toner image 526CT having a density of 100% and having a larger amount of toner than the yellow toner image 522Y is superimposed.

  As described above, in the image forming system 1 according to the second embodiment, as shown in FIG. 14, when the number of toner image fixing processes is the same, the transparent toner image is superimposed on the toner image with a small amount of toner. By forming them together, it is possible to suppress a difference in glossiness due to a difference in toner amount. Further, for toner images having different numbers of fixing processes of the toner image, the toner amount of the transparent toner image is controlled by considering the difference in the amount of toner in addition to the number of fixing processes. The occurrence of a difference in gloss between a plurality of images in the same plane is suppressed.

[Embodiment 3]
FIG. 15 shows an image forming system according to the third embodiment. In the image forming system according to the third embodiment, in the toner image formed on both sides of the recording medium, the selecting unit may change the toner image on the surface opposite to the surface on which the toner image with the largest number of fixing processes exists. It is configured to be selected.

  In the image forming system 1, for example, as shown in FIGS. 16A and 16B, in the color image forming apparatus 2, a cyan toner image 531 </ b> C is formed on the first surface 5 a of the recording paper 5, and the cyan image is formed. After the color toner image 531C is fixed on the first surface 5a of the recording paper 5 by the fixing device 40, a cyan toner image 532C is similarly formed on the second surface 5b of the recording paper 5, and the cyan toner image 532C is formed. May be subjected to a fixing process on the second surface 5b of the recording paper 5 by the fixing device 40.

  Thereafter, in the image forming system 1, the recording sheet 5 having the cyan toner images 531 </ b> C and 532 </ b> C formed on the first surface 5 a and the second surface 5 b by the color image forming apparatus 2 is supplied to the external paper feeding device of the special color image forming apparatus 3. As shown in FIG. 16C, in the special color image forming apparatus 3, a custom color toner image 533CU is formed on the first surface 5a of the recording paper 5, and the custom color toner image 533CU is fixed. In some cases, an image is formed by performing a fixing process on the first surface 5a of the recording paper 5 by the device 40.

  Further, in the image forming system 1, as shown in FIG. 16D, in the special color image forming apparatus 3, the custom color toner image 534 CU is formed on the second surface 5 b of the recording paper 5 by turning over the recording paper 5. Is formed, and the fixing device 40 performs a fixing process on the second surface 5b of the recording paper 5 with the custom color toner image 534CU to form an image.

  Then, of the toner images formed on the front and back surfaces 5a and 5b of the recording paper 5, the cyan toner image 531C formed on the first surface 5a of the recording paper 5 is fixed by the fixing device 40 of the color image forming apparatus 2. After receiving the two fixing processes, the fixing device 40 of the special color image forming apparatus 3 similarly receives two fixing processes, and receives a total of four fixing processes.

  On the other hand, among the toner images formed on the recording paper 5, the cyan toner image 532 </ b> C formed on the second surface 5 b of the recording paper 5 undergoes two fixing processes by the fixing device 40 of the color image forming apparatus 2. Thereafter, the fixing device 40 of the spot color image forming apparatus 3 receives one fixing process, and receives a total of three fixing processes.

  Further, among the toner images formed on the recording sheet 5, the custom color toner image 533 CU formed on the first surface 5 a of the recording sheet 5 is subjected to two fixing processes by the fixing device 40 of the special color image forming apparatus 3. receive.

  Further, among the toner images formed on the recording paper 5, the custom color toner image 534CU formed on the second surface 5 b of the recording paper 5 undergoes the fixing process only once by the fixing device 40 of the special color image forming apparatus 3. receive.

  As described above, in the image forming system 1, as shown in FIG. 16D, the cyan toner image 531C formed on the first surface (front surface) 5a, which is the same surface of the recording paper 5, and the custom color toner In the image 533CU, the number of fixing processes received by the cyan toner image 531C is four, whereas the number of fixing processes received by the custom color toner image 533CU is two, On one surface 5a, an in-plane gloss difference occurs between the cyan toner image 531C and the custom color toner image 533CU due to the difference in the number of times of the fixing process.

  Further, in the image forming system 1, in the cyan toner image 532C and the custom color toner image 534CU formed on the second surface 5b, which is the same surface of the recording paper 5, the number of fixing processes received by the cyan toner image 532C Is three times, the number of times of the fixing process received by the custom-color toner image 534CU is one, and the cyan toner image 532C and the custom-color toner image 534CU on the second surface 5b of the recording sheet 5. , A difference in in-plane glossiness also occurs due to the difference in the number of times of the fixing process.

  Furthermore, in the image forming system 1, when the cyan toner images 531 C and 532 C of the same color formed on the front and back surfaces 5 a and 5 b of the recording paper 5 are respectively viewed, the cyan formed on the first surface 5 a of the recording paper 5 The number of times of the fixing process received by the toner image 531C is four, whereas the number of times of the fixing process received by the cyan toner image 532C formed on the second surface 5b of the recording sheet 5 is three. Also, there is a difference in glossiness between both surfaces due to the difference in the number of times of the fixing process.

  Similarly, in the image forming system 1, when the toner images 533 CU and 534 CU of the same color formed on the front and back surfaces 5 a and 5 b of the recording paper 5 are viewed, the toner images are formed on the first surface 5 a of the recording paper 5. While the number of fixing processes received by the custom color toner image 533CU is two, the number of fixing processes received by the custom color toner image 534CU formed on the second surface 5b of the recording sheet 5 is one. This is also the number of times, and a difference in glossiness between the two surfaces also occurs due to the number of times of the fixing process.

  Therefore, in the third embodiment, the control unit 401 of the server device 4 determines whether the toner image formed on both sides of the recording paper 5 is opposite to the surface on which the toner image with the largest number of fixing processes is present. The toner image formed of a transparent toner is superimposed on the toner image to be formed.

  In addition, the control unit 401 of the server device 4 selects a toner image having a small number of times of the fixing process according to the difference in the number of times of the fixing process among the toner images formed on the same surface of the recording paper 5, and Is configured such that a toner image made of a transparent toner is superimposed on a toner image having a small number of times.

  That is, in the third embodiment, as shown in FIG. 15D, the control unit 401 of the server device 4 determines that the number of times of the fixing process is smaller in the toner images formed on both sides 5a and 5b of the recording paper 5. The same cyan toner image 532C located on the second surface 5b opposite to the cyan toner image 531C formed on the first surface 5a of the recording paper 5 which is the most (four times) toner image. The toner image 535CT made of transparent toner is superimposed.

  At this time, the toner amount of the transparent toner image 535CT to be superimposed on the cyan toner image 532C formed on the second surface 5b of the recording paper 5 is a difference in the number of fixing processes as shown in FIG. 8 ( Considering (4 times)-(3 times) = 1 time, the toner amount is set to a small amount (for example, the density is about 30 to 50%).

  Further, in the third embodiment, as shown in FIGS. 15C and 15D, the control unit 401 of the server device 4 controls the toner image formed on both sides 5a and 5b of the recording paper 5 to record the recording paper. 5, the number of times of fixing of the custom color toner image 533CU formed on the first surface 5a of the recording sheet 5 and the custom color toner image 534CU formed on the second surface 5b of the recording sheet 5 is smaller than that of the first surface 5a of the recording sheet 5. The toner images 536CT and 537CT made of transparent toner are formed so that the second surface 5b becomes larger.

  At this time, as shown in FIG. 8, the toner amount of the transparent toner image 537CT to be superimposed on the custom color toner image 534CU formed on the second surface 5b of the recording paper 5 is a difference in the number of fixing processes (see FIG. 8). Considering (2 times)-(1 time) = 1 time, a large amount of toner (for example, a density of about 150 to 200%) is set.

  On the other hand, as shown in FIG. 8, the toner amount of the transparent toner image 536CT to be superimposed on the custom color toner image 533CU formed on the first surface 5a of the recording paper 5 is the transparent toner image formed on the second surface 5b. The value is set to a value smaller than the toner amount of the image 537CT, but is the difference between the number of times of fixing processing with the cyan toner image 531C formed on the first surface 5a of the recording sheet 5 (4 times) − (2 times) ) = 2 times, the toner amount is set to a relatively large amount (for example, about 100% density).

  As described above, in the third embodiment, the toner image formed on the front and back surfaces of the recording paper 5 is configured such that the toner image made of the transparent toner is superimposed on the toner image on the surface on which the number of fixing processes is small. The occurrence of a gloss difference in the toner image on the front and back surfaces 5a and 5b of the recording paper 5 is suppressed.

[Embodiment 4]
FIG. 17 shows an image forming apparatus according to the fourth embodiment. In the fourth embodiment, the selection unit is configured to form the transparent toner image on an arbitrary layer among the toner images on the recording medium.

  That is, in the image forming system 1 according to the fourth embodiment, for example, as shown in FIG. 17A, in the color image forming apparatus 2 and the special color image forming apparatus 3, the first surface 5a of the recording paper 5 A red toner image 541P is formed by superimposing the white, magenta and yellow toner images 541W, 541M and 541Y, and the yellow and magenta colors are superimposed at different positions on the first surface 5a of the recording paper 5. In some cases, a red toner image 542R is formed, and a single-color silver toner image 543Si is formed at a different position on the first surface 5a of the recording sheet 5.

  In this case, the red toner image 541P formed on the first surface 5a of the recording sheet 5 and superimposed with the white, magenta and yellow toner images 541W, 541M and 541Y has two fixing processes. , The toner amount is the largest. Next, the red toner image 542R formed on the first surface 5a of the recording sheet 5 and superimposed on the yellow and magenta toner images 542Y and 542M has two fixing processes and has a toner amount of two. Moderate. Further, the silver toner image 543Si formed on the first surface 5a of the recording paper 5 has the fixing process performed once and has the smallest toner amount.

  Therefore, in the fourth embodiment, the number of times of the fixing process is one, and the transparent toner image 544CT having the largest toner amount is formed to be superimposed on the silver toner image 543Si having the smallest toner amount. You.

  In the fourth embodiment, the number of times of the fixing process is two, and the red toner image 542R in which the yellow and magenta toner images 542Y and 542M each having a medium toner amount are superimposed on each other. The transparent toner image 545CT having a small amount of toner is formed so as to be superimposed.

  At this time, the position where the transparent toner image 545CT is superimposed is the red toner image 542R obtained by superimposing the yellow and magenta toner images 542Y and 542M as shown in FIGS. May be formed on the surface of the recording paper 5 which is the lower layer, or of the red toner image 542R obtained by superimposing the yellow and magenta toner images 542Y and 542M, the yellow and magenta toner images 542Y. , 542M.

  However, the position where the transparent toner image can be formed depends on the order in which the color image forming apparatus 2 and the special color image forming apparatus 3 form the images on the recording paper 5 and the image formation for forming the transparent toner image in the special color image forming apparatus 3. It is limited by the arrangement of the device 10CT and the like.

  Therefore, a range allowed by the order of forming images on the recording paper 5 in the color image forming apparatus 2 and the special color image forming apparatus 3 and the arrangement of the image forming apparatus 10CT for forming a transparent toner image in the special color image forming apparatus 3 and the like. , A transparent toner image can be formed on an arbitrary layer of the toner image on the recording paper 5.

[Embodiment 5]
FIG. 18 shows an image forming apparatus according to the fifth embodiment. In the fifth embodiment, a first image forming unit that forms a toner image on a recording medium and a second image forming unit that forms a transparent toner image by superimposing the toner image on the recording medium include one image forming apparatus. Are configured to be provided.

  That is, as shown in FIG. 18, the color image forming apparatus 2 according to the fifth embodiment includes a plurality of first image forming units that form a toner image that is developed with toner constituting a developer. The image forming apparatus includes an image forming apparatus 10 and an image forming apparatus 10CT as an example of a second image forming unit that forms a transparent toner image developed with transparent toner.

  The image forming apparatus 10 includes four image forming apparatuses 10Y, 10M, 10C, and 10K that respectively form four color toner images of yellow (Y), magenta (M), cyan (C), and black (K). And an image forming apparatus 10W for forming a white (W) toner image. These five image forming apparatuses 10 (Y, M, C, K, W) are arranged in a line in the horizontal direction in the internal space of the apparatus main body 2a.

  The control device 100 selects a toner image on the recording sheet 5 on which the transparent toner image is formed by the image forming apparatus 10CT that forms the transparent toner image in accordance with the number of times of the fixing process that the toner image on the recording sheet 5 receives. It has a function as selection means.

  In the fifth embodiment, the image forming apparatus 10CT that forms a transparent toner image is disposed on the most upstream side along the moving direction B of the intermediate transfer belt 21. Further, an image forming apparatus 10W for forming a white toner image as a special color is arranged at the most downstream side along the moving direction B of the intermediate transfer belt 21.

  In the color image forming apparatus 2, the image forming apparatus 10CT and the image forming apparatuses 10 (Y, M, C, K, W) are integrally unitized, and are configured to be detachable from the apparatus main body 2a. . For this reason, the color image forming apparatus 2 exchanges the arrangement of the image forming apparatus 10CT and the image forming apparatuses 10 (Y, M, C, K, W) to obtain transparent (CT), yellow (Y), and magenta (M). ), Cyan (C), black (K), and white (W) images can be formed in a different order.

  In the first to fourth embodiments, the case where an image is formed on the recording sheet 5 by the color image forming apparatus 2 and then an image is formed on the same recording sheet 5 by the special color image forming apparatus 3 has been described. The image may be formed on the recording paper 5 by the color image forming apparatus 2 after forming the image on the recording paper 5 by the forming device 3 first. In this case, the external paper feeding device 80 is attached to the color image forming apparatus 2.

DESCRIPTION OF SYMBOLS 1 ... Image forming system 2 ... Color image forming apparatus 2a ... Main body 10Y-10K ... Color image forming apparatus 3 ... Special color image forming apparatus 3a ... Main body 10CT ... Transparent toner image forming apparatus 10CT ... Special color image forming apparatus 4. Server device 401 Control unit

Claims (10)

First image forming means for forming a toner image on a recording medium;
Second image forming means for forming a transparent toner image by superimposing the toner image on the recording medium;
A single or a plurality of fixing means for fixing at least a part of the toner image of the recording medium to undergo a plurality of fixing processes,
Selecting means for selecting the toner image of the recording medium on which the second image forming means forms the transparent toner image by superimposing, in accordance with the number of times of the fixing process received by the toner image of the recording medium;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the selection unit selects a toner image having a smaller number of times of the fixing process than a toner image having a largest number of times of the fixing process.   The image forming apparatus according to claim 2, wherein the selection unit changes a toner amount of the transparent toner image according to a number of times of the fixing process.   4. The image forming apparatus according to claim 3, wherein the selecting unit increases the toner amount of the transparent toner image superimposed on the toner image having a small toner amount when the number of times of the fixing processing of the toner image is the same. 5.   The image forming apparatus according to claim 1, wherein the selecting unit changes a toner amount of the transparent toner image according to a total toner amount of the toner image formed by the first image forming unit.   6. The image forming apparatus according to claim 5, wherein the selection unit forms the transparent toner image on a toner image having a smaller total toner amount than the largest toner image formed by the first image forming unit. 7. The first image forming unit forms the toner image on both surfaces of the recording medium,
The selecting unit may be configured such that the second image forming unit superimposes the transparent toner image on at least one surface of the recording medium in accordance with the number of times of the fixing process received by the toner images formed on both surfaces of the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed together.   8. The image forming apparatus according to claim 7, wherein the selecting unit selects a toner image on a surface opposite to a surface on which the toner image having the largest number of fixing processes is present among the toner images formed on both surfaces of the recording medium. Image forming device.   The image forming apparatus according to claim 1, wherein the selection unit forms the transparent toner image on an arbitrary layer among the toner images on the recording medium.   The image forming system according to claim 1, wherein the first image forming unit and the second image forming unit include different image forming apparatuses each including the fixing unit.

Images