JP6189821B2 - Image forming apparatus - Google Patents

Description

  Embodiments described herein relate generally to an image forming apparatus.

  As one form of an image forming apparatus, an image is printed on a sheet by printing an image on a sheet using a recording material, for example, a decolorable toner, and further applying a decoloring process to the toner that forms the image by heating. A device having a so-called decoloring device for erasing the image is known. This erasing apparatus includes a reading unit that reads an image to leave an image before erasing, a erasing unit that erases toner that forms an image, and whether or not erasing processing has been normally performed after erasing. In order to determine whether or not the image is read again by the above-described reading unit. When erasing the image formed on the paper, a series of operations are performed in which the content of the paper is read and stored by the reading unit and is erased.

  In such an image forming apparatus, when an image is erased and an image is formed repeatedly by reusing the sheet, the sheet is easily charged with static electricity. A sheet on which image erasing and image formation are repeated (in other words, a sheet recycled a plurality of times) deteriorates in paper discharge consistency. A specific example of the deterioration in the discharge consistency is that the paper discharged earlier and the paper discharged later repel each other or the paper and the image forming apparatus repel each other, so that the paper floats and falls to the floor. For example, the printed paper sticks to the top surface of the paper discharge unit, or the paper is scattered on the paper discharge unit.

Japanese Patent No. 5453504

  The problem to be solved by the embodiments of the present invention is to provide an image forming apparatus having good sheet discharge consistency even when an image is formed on a sheet in which image erasure and image formation are repeated.

Therefore, in order to achieve the above-described problem, the following measures are taken in the embodiment of the present invention. A transport path for transporting the paper, a paper discharge section for storing the paper transported by the transport path, a static elimination transport path in which at least one static elimination section for discharging the paper is disposed, and the transport path of the paper A sheet discharge unit or a conveyance path changing unit that selectively changes to the charge removal conveyance path, an acquisition unit that acquires information on sheet reuse, and the charge removal conveyance path are acquired from the downstream side of the conveyance path change unit. A control unit that forms a path upstream of the image forming unit and controls the conveyance path changing unit according to information acquired by the acquiring unit.

1 is a cross-sectional view schematically showing an image forming apparatus in the present embodiment. 1 is a block diagram of an image forming apparatus in the present embodiment. Explanatory drawing of the paper in this Embodiment. 6 is a flowchart illustrating a print job process of the image forming apparatus according to the present embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, an MFP (Multi-Function Peripheral) will be described as an example of the image forming apparatus.

  This embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view schematically illustrating a configuration example of the MFP 100 according to the embodiment. As illustrated in FIG. 1, the MFP 100 includes a scanner unit 1, a printer unit 2, an operation panel 4, and a system control unit 5.

  The scanner unit 1 is an apparatus that reads an image of a document and converts it into image data. The scanner unit 1 has a well-known configuration and is configured by, for example, a CCD line sensor that converts an image of a document on a reading surface into image data. The scanner unit 1 may scan a document placed on a platen glass (not shown), or may read an image of a document conveyed by an automatic document feeder (ADF). It may be. The scanner unit 1 is installed on the upper side of the main body of the MFP 100, for example. The scanner unit 1 is controlled by the system control unit 5.

  The printer unit 2 forms an image on a sheet as an image forming medium. In the present embodiment, the printer unit 2 is an electrophotographic image forming apparatus. The printer unit 2 forms an image using five types of toner (for example, yellow (Y), cyan (C), magenta (M), black (K), and erasure (D)). Yellow (Y), cyan (C), magenta (M), and black (K) toners are non-erasable toners that cannot be erased even when heat of a predetermined temperature or higher is applied. The erasing toner (D) is a toner that can be decolored (colorless) by heating at a predetermined temperature or higher. The color of the erasing toner (D) is, for example, dark blue or black.

  The erasing toner is formed, for example, by adding a color material to a binder resin. The erasable color material includes a color developing compound, a developer, and an erasing agent. Examples of the color developing compound include leuco dyes. Examples of the developer include phenols. Examples of the erasing agent include a substance that is compatible with the color developing compound when heated and does not have an affinity for the developer. The erasable colorant develops color due to the interaction between the color developing compound and the developer, and is erased because the interaction between the color developing compound and the developer is cut off by heating above the erasing temperature.

  In the configuration example illustrated in FIG. 1, the printer unit 2 includes a plurality of paper feed cassettes 20 (20 </ b> A, 20 </ b> B, and 20 </ b> C) as a paper feed unit that supplies paper for printing an image. For example, each of the paper feed cassettes 20A, 20B, and 20C is provided in a detachable state at the bottom of the MFP 100 main body. Each of these paper feed cassettes 20A, 20B, and 20C stores paper of a set type (for example, size and paper quality). The printer unit 2 may include a manual feed tray (not shown) as another paper feeding unit.

  Setting information such as information relating to paper stored in each of the paper feed cassettes 20A, 20B, and 20C is stored in a nonvolatile memory. The printer unit 2 selects a paper feed cassette that stores paper used for print processing according to the setting information. The printer unit 2 prints an image on paper fed from the selected paper feed cassette. When the printer unit 2 has a manual feed tray, the size of the paper set in the manual feed tray input from the operation panel 4 may be stored in the nonvolatile memory described above.

  In the following description, since the paper is transported from the paper supply unit 20 to the paper discharge unit 30, the paper supply unit 20 side is the upstream side with respect to the paper transport direction, and the paper discharge unit 30 side is the paper transport. The downstream side with respect to the direction.

  The transport unit 22 transports paper within the printer unit 2. The transport unit 22 transports the paper supplied from the corresponding paper feed cassette 20A, 20B, or 20C to the registration roller 24 by the pickup rollers 21A, 21B, or 21C. The registration roller 24 conveys the sheet to the transfer position at a timing at which an image is transferred from the intermediate transfer belt 27 described later to the sheet.

  Further, a reading unit 23 is provided in the conveyance unit 22 between the paper supply unit 20 and the intermediate transfer belt 27 (this reading unit 23 functions as an acquisition unit). Specifically, the reading unit 23 is provided on the upstream side of the sheet conveyance with respect to the registration roller 24 and on the downstream side of the junction of the reversing paths by the automatic duplex unit (ADU) 31 described later. The reading unit 23 is, for example, a CCD sensor, and is an optical sensor including a light emitting unit and a light receiving unit (the reading unit 23 corresponds to an acquisition unit). The reading unit 23 reads the number of times printed on a sheet to be described later. The number of times of printing indicates the state of paper reuse. As shown in FIG. 3, the sheet read in this embodiment is printed with an identifier representing the number of times the same sheet has been used for printing as information on how the sheet has been reused. One black horizontal line represents the number of times of printing. That is, the sheet identifier shown in FIG. 3 indicates that the sheet has been printed three times. The number of times printed on the paper is printed with a non-erasable toner (for example, black (K)). This is because when erasable toner is erased by an erasing device (not shown), the toner is not erased together with the erasable toner.

  The image forming unit 25, the exposure unit 26, the intermediate transfer belt 27, and the transfer unit 28 function as a well-known image forming unit that forms an image. The image forming unit 25 forms an image to be transferred to a sheet. In the configuration example of generating the color image shown in FIG. 1, the image forming unit 25Y forms an image corresponding to yellow with yellow toner by color-separating the original image, which will be described in detail later. Similarly, the image forming unit 25M forms an image with magenta toner. The image forming unit 25C forms an image with cyan toner. The image forming unit 25K forms an image with black toner. The image forming units 25Y, 25M, 25C, and 25K superimpose and transfer the toner images of the respective colors on the intermediate transfer belt 27. On the other hand, the image forming unit 25D is an erasable toner that is used when paper is reused and forms an erasable document image. As described above, the color of the erasable toner is dark blue or black. Accordingly, the image formed by the image forming unit 25D is a monochrome (single color) image. Each of the image forming units 25Y, 25M, 25C, 25K, and 25D has a known configuration, for example, a photosensitive drum, a charging charger, a developing unit including toner, a charge eliminating unit, and the like (only shown in FIG. 1). Note that the image forming unit 25D is used only when reusing paper, but since the configuration and operation are the same as those of other image forming units, the following description will be made simultaneously.

  Although not shown, each of the image forming units 25Y, 25M, 25C, 25K, and 25D has a known sensor such as a potential sensor and a density sensor. The potential sensor is a sensor that detects a surface potential of a well-known photosensitive drum included in each image forming unit. In each of the image forming units 25Y, 25M, 25C, 25K, and 25D, a known charging charger charges the surface of the photosensitive drum before the photosensitive drum is exposed by an exposure unit 26 described later. The system control unit 5 can change the charging condition by the charging charger. The potential sensor detects the surface potential of the photosensitive drum whose surface is charged by the charging charger. The density sensor detects the density of a toner image transferred onto an intermediate transfer belt 27 described later. The density sensor may detect the density of the toner image formed on the photosensitive drum.

    The exposure unit 26 forms an electrostatic latent image with laser light on the charged photosensitive drums of the image forming units 25Y, 25M, 25C, 25K, and 25D as described above. The electrostatic latent image formed on each photosensitive drum is an image developed with toner of each color. That is, the exposure unit 26 irradiates each photosensitive drum with laser light corresponding to each image forming unit controlled according to image data through an optical system such as a polygon mirror. The exposure unit 26 controls the power of the laser beam in accordance with a control signal from the system control unit 5. The exposure unit 26 also controls the modulation amount of the pulse width for controlling the emission of the laser light according to the control signal from the system control unit 5.

  As described above, each of the image forming units 25Y, 25M, 25C, 25K, and 25D develops the electrostatic latent images formed on the respective photosensitive drums with toner of each color by the developing unit. Each of the image forming units 25Y, 25M, 25C, 25K, and 25D forms a toner image as a visible image on the photosensitive drum. The intermediate transfer belt 27 is an intermediate transfer member. When a color image is formed with the above-described non-erasable toner, each of the image forming units 25Y, 25M, 25C, and 25K transfers the toner image formed on the photosensitive drum onto the intermediate transfer belt 27 (primary transfer). ) Specifically, each of the image forming units 25Y, 25M, 25C, and 25K applies a transfer bias to the toner image at the primary transfer position. Each of the image forming units 25Y, 25M, 25C, and 25K controls the transfer bias by the transfer current. The toner image on each photosensitive drum is transferred to the intermediate transfer belt 27 by a transfer bias at each primary transfer position. The system control unit 5 controls the transfer current that each image forming unit uses for the primary transfer process. On the other hand, when the paper is reused, that is, when a monochrome image is formed with erasable toner, a toner image as a visible image is formed on the photosensitive drum by the image forming unit 25D. This toner image is transferred to the intermediate transfer belt 27 as described above. At this time, as described above, the sheet is printed as information on the reuse of the sheet at the edge of the sheet shown in FIG. 3 by another image forming unit having non-erasable toner, for example, 25K (black toner). An identifier representing the number of times is formed as a toner image on the corresponding photosensitive drum and is simultaneously transferred to the intermediate transfer belt 27. In this way, an identifier representing the number of reuses printed at a predetermined position on the sheet is also transferred onto the intermediate transfer belt 27 together with the original image of the erasable toner.

  The transfer unit 28 transfers the toner image on the intermediate transfer belt 27 to a sheet at the secondary transfer position. The transfer unit 28 includes a support roller 28a and a secondary transfer roller 28b provided along the paper conveyance path, and the support roller 28a and the secondary transfer roller 28b are intermediate transfer belts at the secondary transfer position. It is a position which opposes on both sides of 27. The transfer unit 28 applies a transfer bias controlled by a transfer current to the belt 27 at the secondary transfer position. The transfer unit 28 transfers the toner image on the intermediate transfer belt 27 to a sheet by a transfer bias. The system control unit 5 controls a transfer current used for the secondary transfer process.

  The fixing device 29 has a function of fixing toner on a sheet. For example, in the embodiment, the fixing device 29 fixes the toner image on the paper by heat and pressure applied to the paper.

  In the configuration example shown in FIG. 1, the fixing device 29 includes a heat roller 29b having a heating unit 29a and a pressure roller 29c in contact with a fixing belt (not shown) heated by the heat roller 29b in a pressurized state. The heating unit 29a may be a heater capable of controlling the temperature. For example, the heating unit 29a may be configured by a heater lamp such as a halogen lamp, or may be an induction heating (IH) type heater. Moreover, you may comprise the heating part 29a with a some heater. The fixing device 29 further includes a temperature sensor for measuring the temperature of the heat roller 29b.

  When performing the fixing process for fixing the toner image on the paper, the system control unit 5 controls the temperature of the fixing device 29 to be the fixing temperature. The fixing device 29 heats the sheet on which the toner image is transferred by the transfer unit 28 at a fixing temperature while applying pressure. As a result, the fixing device 29 fixes the toner image on the paper. Further, the fixed sheet is conveyed to either the paper discharge unit 30 or the ADU 31.

  Regarding the control of the fixing temperature of the fixing device 29, when the paper is reused, that is, when the erasable toner and the non-erasable toner are fixed together, the fixing device 29 adjusts the temperature, pressure and paper conveyance speed. adjust. Control is performed such that the sheet conveyance speed, that is, the rotation speed of the heat roller 29b and the pressure roller 29c is decreased, and the time during which pressure is applied to the sheet is lengthened.

  When the paper fixed by the fixing device 29 is discharged, the paper is carried out to the paper discharge unit 30. When an image is also formed on the back surface of the paper fixed by the fixing device 29, the paper is once transported to the paper discharge unit 30 side, then switched back and transported to the ADU 31. In this case, the ADU 31 again supplies the sheet reversed by the switchback to the upstream side of the registration roller 24 and the reading unit 23.

  In the present embodiment, a conveyance path changing unit 32 is provided on the downstream side of the fixing device 29 and the upstream side of the paper discharge unit 30. The conveyance path changing unit 32 includes a motor, a gear, a flapper member, and the like, and switches the sheet conveyance path to the paper discharge unit 30 or the ADU 31. By default, the conveyance path changing unit 32 allows a conveyance path from the fixing unit 29 to the paper discharge unit 30. When the identifier is formed on the sheet conveyed by the reading unit 23, the conveyance path changing unit 32 forms a conveyance path from the fixing device 29 to the ADU 31. At this time, the sheet is directly conveyed from the fixing unit 29 to the ADU 31. As described above, since the sheet is not transported to the paper discharge unit 30 and switched back, the sheet is not reversed.

  A plurality of static eliminating sections 33 are provided in the transport path of the ADU 31. The static elimination part 33 is the hair which consists of conductive fibers, for example, a polypropylene. When the sheet being transported touches the charge removal unit 33, the static electricity on the sheet is removed. The ADU 31 corresponds to a static elimination conveyance path.

  Although not shown, a plurality of well-known paper position detection sensors for grasping the paper position are provided in the conveyance path of the printer unit 2. The paper position sensor is, for example, an infrared sensor including a light emitting unit and a light receiving unit. The paper position is grasped by the paper blocking the infrared sensor.

The operation panel 4 is a user interface. The operation panel 4 includes various buttons and a display unit 4a including a touch panel 4b. The system control unit 5 controls the contents displayed on the display unit 4 a of the operation panel 4. Further, the operation panel 4 outputs information input to the touch panel 4b or the button of the display unit 4a to the system control unit 5. Further, at the time of printing, input of information necessary for printing such as the number of printed sheets and density is accepted.

  Next, the configuration of the control system of MFP 100 will be described. FIG. 2 is a block diagram of MFP 100 according to the present embodiment. Via a system bus 52, a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 53, a RAM (Random Access Memory) 54, a HDD (Hard Disk Drive) 55, an external I / F (Interface) 56, a printer unit. 2. The operation panel 4 is connected. The CPU 51, ROM 53, and RAM 54 constitute the system control unit 5 (see FIG. 1).

  The ROM 53 stores in advance a program and threshold values for operating the CPU 51 as each function. For example, a fixing temperature at which erasable toner and non-erasable toner can be fixed is stored. Further, in the present embodiment, a static elimination threshold that is a threshold of whether the paper is conveyed to the paper discharge unit 30 or the ADU (static elimination conveyance path) 31 is stored. The static elimination threshold is a value for determining the number of static eliminations. In the present embodiment, for example, “5” is stored. When it is determined that the same sheet has been used for printing (reuse) one or more times, the sheet is controlled to be discharged to the ADU (static discharge conveyance path) 31 and discharged. In the present embodiment, when the number of times of printing on the same sheet is 4 or less, for example, the sheet is discharged once, and when the number of times of printing is equal to or greater than the discharge threshold (5), it is twice. Static elimination is executed.

  Various memory areas such as a work area serving as a work area for data processing by a program are dynamically formed in the RAM 54. Further, in the present embodiment, a printing number storage area for storing the number of printing times read by the reading unit 23 is provided. For example, “0” is stored in the print count storage area by default.

  The HDD 55 is installed with an OS (Operating System) that operates the MFP 100. In addition, it has a temporary storage area for temporarily storing image information read by the scanner unit 1.

  The external I / F 56 is an interface for communicating with an external device. For example, the external I / F 56 receives print data transmitted together with a print request from an external device, for example, a client terminal (PC: Personal Computer). The external I / F 56 may be an interface that performs data communication with an external device. For example, the external I / F 56 may be an object (USB memory or the like) locally connected to the external device, or a network for communicating via a network. It may be an interface.

  Since the scanner unit 1, the printer unit 2, and the operation panel 4 have been described above, they are omitted.

  In MFP 100 having the above configuration, MFP 100 executes the print job shown in FIG. 4 based on a preset program.

  When the MFP 100 performs a print job, a document to be copied is already placed on the platen glass of the scanner unit 1. MFP 100 reads this document. In this case, it is assumed that MFP 100 is set to print an image on a sheet with erasable toner in order to reuse the sheet. In addition, it is assumed that a sheet that is reused for printing is already set in, for example, the sheet feeding cassette 20B of the sheet feeding unit. It is assumed that the number of times of printing is written on all sheets set in the sheet feeding cassette 20B as shown in FIG. The image information to be printed may be input to the MFP 100 via the interface from the PC as the client terminal as described above, for example, in addition to reading the document by the scanner unit 1 described above. In this print job, single-sided printing is performed once. By default, the conveyance path changing unit 32 allows a conveyance path from the fixing unit 29 to the paper discharge unit 30.

  The system control unit 5 receives input of print information (number of copies to be printed, density to be printed, etc.) from the operation panel 4 and stores it in a predetermined area of the RAM 54. Next, the system control unit 5 drives the scanner unit 2 to acquire image information to be copied (printed) (ACT 101). In the following description, the reading of the original by the scanner unit 1 and the well-known image formation by the exposure unit 26 and the image forming unit 25 are not mentioned, but the toner image is primarily applied to the intermediate transfer belt 27 by the operation of each unit described above. Shall be transcribed.

  The system control unit 5 picks up a sheet from the sheet feeding cassette 20B of the sheet feeding unit by a pickup roller 21B. Then, the system control unit 5 controls the conveyance unit 22 to convey the sheet to the registration roller 24 (ACT 102).

  The system control unit 5 reads the identifier (number of times of printing) shown in FIG. 3 printed on the sheet being conveyed to the registration roller by controlling the reading unit 23. The system control unit 5 stores the read print count in the print count storage area of the RAM 54 (ACT 103).

  The system control unit 5 determines whether an identifier is formed on the sheet. Specifically, the system control unit 5 determines whether or not a value of 1 or more is stored in the print count storage area of the RAM 54 (ACT 104).

  If the system controller 5 determines that one or more values are not stored in the print count storage area of the RAM 54 (No in Act 104), the transfer unit 28 transfers the toner image to the paper. At this time, an image is formed with a non-erasable toner (for example, black (K)), and an image with an identifier obtained by adding 1 to the number of times of printing compared to the copy source image is transferred. Further, images other than the identifier are formed with erasable toner (erasable toner (D)). Then, the sheet is conveyed to the fixing device 29. The system controller 5 controls the fixing device 29 to fix the image formed on the sheet, that is, the print image and the identifier image (Act 105).

  When the fixing of the paper is completed by the fixing device 29, the system control unit 5 conveys the paper to the paper discharge unit 30 (Act 112) and ends the print job.

  On the other hand, when the system control unit 5 determines in Act 104 that a value of 1 or more is stored in the print count storage area of the RAM 54 (Yes in Act 104), the system control unit 5 drives the conveyance path changing unit 32 to fix the value. A path from the container 29 to the ADU (static elimination transport path) 31 is formed (Act 106).

  Subsequently, the system control unit 5 reads the static elimination threshold (5) stored in the ROM 53, and determines whether or not a value of 5 or more is stored in the print count storage area of the RAM 54 (Act 107). If the system control unit 5 determines that a value of 5 or more is not stored in the print count storage area of the RAM 54 (No in Act 107), the system control unit 5 sets the transfer unit 28 and the fixing device 29 in the same manner as Act 105. Control is performed to transfer and fix the image on the sheet (Act 108).

  This time, the conveyance path changing unit 32 forms a path from the fixing device 29 to the ADU (static elimination conveyance path) 31 as described above. For this reason, after the paper is fixed by the fixing device 29, the paper is directly conveyed from the fixing device 29 to the ADU (static elimination conveyance path) 31. The ADU (static elimination transport path) 31 is provided with a plurality of static eliminating units 33. The sheet conveyed through the ADU (static elimination conveyance path) 31 contacts the neutralization unit 33. When the sheet comes into contact with the charge removal unit 33, static electricity charged on the sheet is discharged by the charge removal brush of the charge removal unit 33. The sheet is conveyed again through the ADU 31 (static elimination conveyance path) 31 to the upstream side of the registration roller 24. (Act109).

  When the sheet is conveyed to the upstream side of the registration roller 24, the system control unit 5 controls the conveyance path changing unit 32 to form a path from the fixing device 29 to the paper discharge unit 30. Then, the paper is conveyed to the paper discharge unit 30 (Act 112), and the processing is completed.

  On the other hand, if the system control unit 5 determines in ACT 107 that a value of 5 or more is stored in the print count storage area of the RAM 54 (Yes in Act 107), first, similarly to Act 105, the system control unit 5 The fixing device 29 is controlled to transfer and fix the image on the paper (Act 110).

The conveyance path changing unit 32 forms a path from the fixing device 29 to the ADU (static elimination conveyance path) 31 . For this reason, after the paper is fixed by the fixing device 29, the paper is directly conveyed from the fixing device 29 to the ADU (static elimination conveyance path) 31. The ADU (static elimination transport path) 31 is provided with a plurality of static eliminating units 33. The sheet is discharged by contacting the discharging unit 33. Once discharged, the sheet is transported to the upstream side of the registration roller 24 after passing through the ADU (static discharge transport path) 31. The system control unit 5 again conveys the sheet to the ADU (static elimination conveyance path) 31, and the sheet is de-charged again by the plural neutralization units 33 (Act 111).

  Thereafter, the system control unit 5 controls the conveyance path changing unit 32 to form a path from the fixing device 29 to the paper discharge unit 30. Then, the paper is conveyed to the paper discharge unit 30 (Act 112), and the processing is completed.

  As described above, in the present embodiment, the paper on which the image erasure and the image formation are repeated is discharged before being discharged by the paper discharge unit 30. In particular, when the image formed on the paper is repeatedly erased, static electricity is likely to be charged on the paper. This is because when the toner is colorless by heat, the toner becomes colorless, but the toner remains on the paper. Further, even in an erasing method in which the toner is peeled off by being attached to a medicine or the like, the medicine remains on the paper because the paper is attached to the medicine. The toner and chemicals remaining on the paper change the paper into characteristics like a coated paper. For this reason, static electricity tends to be generated due to friction during the process of transporting the paper. If the paper is reused repeatedly, static electricity is likely to occur, and the paper discharge consistency deteriorates. On the other hand, in this embodiment, when the number of times of printing of the paper is read and it is determined that the conveyed paper is reused, the paper is fed to the ADU 31 (which also functions as a static elimination conveyance path in this embodiment). Transport. As described above, in the present embodiment, the ADU (static elimination conveyance path) 31 is provided with the static elimination unit 33, and the paper conveyed to the ADU (static elimination conveyance path) 31 is neutralized. Since the paper discharged through the ADU (static elimination transport path) 31 has been neutralized, the paper discharge consistency does not deteriorate. Furthermore, in the present embodiment, a threshold value is set for the number of times of reuse, and when the number of reuse times exceeds the threshold value, the number of times that the sheet is conveyed to the ADU (static elimination conveyance path) 31 is increased to reduce the number of static elimination times. Since the number of times of printing is increased, it is possible to appropriately remove static electricity on a sheet that is easily charged.

  In the embodiment of the present invention, the number of times the paper has been printed is read by the reading unit 23 as the acquisition unit that acquires the state of paper reuse, but the present invention is not limited to this. For example, the charged state of the paper may be measured by providing a potential sensor or the like in the conveyance path or each paper feed cassette.

  In this embodiment, the sheet identifier is the number of times the sheet has been printed. However, the present invention is not limited to this. For example, it may be the number of times the paper has been erased by the erasing device. Further, as described in, for example, Japanese Patent Application Laid-Open No. 2011-209711, the number of times the paper has been reused may be estimated from the reflected light of the paper.

  In the present embodiment, description is made to erase the color of the image by heating as an example of the erasing process. However, the erasure described in this embodiment is not limited to the one that erases the color of the image by heat. For example, it may be a process of erasing the color of the image on the sheet by light irradiation, or a process of exfoliating the toner by attaching the paper to the medicine. Erasing may be any configuration that makes an image on a sheet invisible so that the sheet can be reused.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

5 System Control Unit 23 Reading Unit 29 Fixing Unit 54 RAM
55 HDD
100 MFP

Claims (5)

A transport path for transporting paper,
A paper discharge unit for storing paper conveyed by the conveyance path;
A static elimination transport path in which at least one static elimination unit for neutralizing paper is disposed;
A transport path changing section that selectively changes the transport path of the paper to the paper discharge section or the static elimination transport path;
An acquisition unit for acquiring information on paper reuse;
The static elimination conveyance path forms a path from the downstream side of the conveyance path changing unit to the upstream side of the acquisition unit,
In accordance with the information acquired by the acquisition unit, a control unit that controls the transport path changing unit,
An image forming apparatus. Before SL control unit in response to information acquired by the acquiring unit, the image forming apparatus according to claim 1 for determining the number of times the paper is conveyed to the neutralization conveyance path through the conveyance path change section. A transfer unit for transferring a toner image with erasable toner on paper;
A fixing unit for fixing the toner image formed on the paper,
The image forming apparatus according to claim 2, wherein the conveyance path changing unit is provided downstream of the fixing unit. The paper reuse information is an identifier recorded on the paper representing the number of times the image on the paper has been erased or the number of times the image has been printed,
The image forming apparatus according to claim 1, wherein the acquisition unit reads the identifier.   5. The image formation according to claim 4, wherein when the identifier read by the acquisition unit exceeds a predetermined value, the control unit again conveys the sheet that has been discharged through the charge removal conveyance path to the charge removal conveyance path. apparatus.

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