JP6587490B2 - 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 using a recording material, for example, a decolorable toner, and the toner that forms an image by heating is subjected to a decoloring process. A device having a so-called image erasing device for erasing is known. This image erasing apparatus has a reading unit for reading an image to leave an image before erasing and a erasing unit for erasing the toner forming the image, and the erasing process is normally performed after erasing the toner. In order to determine whether or not it has been applied, an image reading unit that reads the image again is known. If it is determined that the erasing process has not been performed normally, the sheet is conveyed to a disposal tray. Therefore, when erasing an image formed on a sheet, a series of operations are performed in which the content of the sheet is read and stored by a reading unit and then erased.

  In such an image erasing apparatus, the image formed on the paper is erased by erasing the erasable toner with heat. For this reason, when erasing, that is, erasing processing is repeated, the erasable toner is stacked on the paper, and the image formed on the paper is gradually not erased. When the remaining amount of erasable toner in the image formed on the sheet exceeds a certain level, the image erasing apparatus determines to discard the sheet. However, since there are usually many horizontally written originals, the image formed on the paper is often biased toward the front (upper side) of the page, and as a result, the second half of the paper page is less erased than the first half of the paper page. May be less.

Japanese Patent No. 5453504

  The problem to be solved by the embodiments of the present invention is to provide an image forming apparatus capable of efficiently reusing paper even on paper with a large amount of unerased image formed with erasable toner. It is to be.

Therefore, in order to achieve the above-described problem, the following measures are taken in the embodiment of the present invention. The formed image is erased, and a first placement unit for placing a sheet having an identifier for storing at least one of a blank area or an unerased area of the sheet, and a sheet on which an image can be formed are placed on the entire surface. A sheet feeding unit having a second placement unit ; an image region that is an area for forming an image using toner; and a storage unit that stores image information including a blank area where an image is not formed using toner. An image forming unit that forms an image based on image information stored in the storage unit, and a sheet that is provided upstream of a position where the image forming unit forms an image on a sheet and is fed by the sheet feeding unit The ratio of the blank area of the image information stored in the storage unit and the reading unit that reads the identifier is a threshold for whether to print using the paper placed on the first placement unit, and cannot be reused If it is greater than or equal to the threshold value, it is placed on the second placement unit. Feeds a sheet, read by feeding to the reading portion of the paper fraction of blank region is placed on the first placement unit if less than nonreusable threshold of the image information stored in the storage unit And a control unit that determines a blank area of the sheet based on the identifier and modifies image information in the storage unit so that an image is formed in the blank area of the sheet.

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 P in this Embodiment. FIG. 3 is an explanatory diagram schematically showing a ratio of each region of a sheet P and an image file in the present embodiment. FIG. 3 is an explanatory diagram schematically illustrating a relationship among a fixing device, a transfer unit, and a reading unit in the present embodiment. Explanatory drawing which shows schematically the image storage area in this Embodiment. 6 is a flowchart showing a process of an erasing job of the image forming apparatus in the present embodiment. Explanatory drawing which shows roughly the image storage area after correction | amendment in this Embodiment. Explanatory drawing which shows roughly the image storage area before correction in this Embodiment, and after correction.

  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 paper P used for printing in the embodiment is shown in FIG. The paper P used for printing has an identifier C at the upper end, a color erasure remaining area N of the color material (erasable toner) at the top of the paper, a blank area K at the middle of the paper, and a color material erase at the bottom. A color (erasure) remaining area N is formed. The identifier C is, for example, a two-dimensional code. As shown in FIG. 4A, the identifier C stores the ratio of the remaining areas N and blank areas K of the paper P. The information stored by the identifier C differs depending on the paper. Further, when the upper end portion on which the identifier C is printed is the upper portion, the ratio of each region is stored in the two-dimensional code in order from the upper portion. In this embodiment, the paper P used for printing is formed with an erase remaining area N of 30%, a blank area K of 50% and an erase remaining area N of 20% in order from the top. For this reason, as shown in FIG. 4A, the two-dimensional code attached to the paper P used for printing holds information of each region in this order. This identifier C is formed when the erasing apparatus performs erasing processing. The identifier C may be printed with erasable toner or may be printed with non-erasable toner.

  Returning to FIG. 1, the scanner unit 1 is an apparatus that reads an image of a document and converts it into image data. For example, the scanner unit 1 is installed on the upper side of the MFP 100. 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 controlled by the system control unit 5.

  The printer unit 2 forms an image on a sheet P as a recording medium. In the present embodiment, the printer unit 2 is an electrophotographic image forming unit. In the case of color, the printer unit 2 prints an image using five types of toners (for example, yellow (Y), cyan (C), magenta (M), black (K), and decolored (D)). Form. Yellow (Y), cyan (C), magenta (M), and black (K) toners are non-erasable toners that cannot be erased even when heat of a predetermined fixing temperature or higher is applied. The decolorable toner (D) is a toner that can be decolored by heating at a predetermined temperature exceeding the fixing temperature. The color of the decoloring toner (D) is, for example, dark blue or black. Details of a known configuration for generating an image by the printer unit 2 will be described later.

  The decolorizing toner used in this embodiment is formed by, for example, containing a color material in 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. Colors that can be erased develop color due to the interaction between the color developing compound and the developer, and the interaction between the color developing compound and the developer is interrupted by heating above the color erasing temperature. Is done.

  In the configuration example illustrated in FIG. 1, the printer unit 2 includes a paper feed cassette 20 (20A, 20B, 20C) as a paper feed unit. 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. These paper feed cassettes 20A, 20B, and 20C contain paper P of the type (for example, size and paper quality) set to each. It is also possible to set each size to the corresponding paper feed cassette after storing, for example, paper P of different sizes in these paper feed cassettes 20A, 20B, 20C. Each paper feed cassette 20A, 20B, 20C is provided with a paper feed sensor. The paper feed unit sensor detects the amount of paper contained in the paper feed tray 22. This paper feed unit sensor is, for example, an infrared sensor. In addition, a mechanical sensor such as a known microswitch can be used. This paper feed unit sensor transmits the detection result to the system control unit 5 described later. Further, the printer unit 2 may include a known manual feed tray (not shown) as another sheet feeding unit. Further, in the present embodiment, the paper cassette 20A stores sheets that can be used on the entire surface, and the paper cassette 20B stores sheets P for the purpose of reuse with an erasure residue as shown in FIG. The In the present embodiment, the paper feed cassette 20B is a first placement unit, and the paper feed cassette 20A is a second placement unit.

  Setting information regarding the paper P 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 accommodates the paper P used for the printing process according to the setting information. The printer unit 2 prints an image on the paper P fed from the selected paper feed cassette. In the case where the printer unit 2 has a manual feed tray, the size of the paper P set in the manual feed tray input from the operation panel 4 may be stored in the nonvolatile memory described above. This nonvolatile memory is an HDD 55 described later.

  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.

  A transport unit 22 shown in FIG. 1 is disposed along the paper transport path in the printer unit 2 and transports the paper P. The transport unit 22 transports the paper P supplied from the corresponding paper feed cassette 20A, 20B, or 20C by the pick-up rollers 21A, 21B, or 21C to a registration roller 24 disposed on the upstream side of the transfer unit 28 described later. To do. The registration roller 24 conveys the paper P to the transfer position at a timing at which an image is transferred from the intermediate transfer belt 27 described later to the paper P.

  A reading unit 23 is provided between the sheet feeding unit 20 and the registration roller 24. More specifically, the reading unit 23 is provided on the upstream side of the registration roller 24 in the transport direction of the paper P and on the downstream side of the confluence of the reversing path by an ADU (Automatic Duplex Unit) 31 described later. The reading unit 23 is, for example, a CCD camera. In the present embodiment, the reading unit 23 reads the identifier C formed on the end of the paper P.

  Details of image formation will be described below. The image forming unit 25, the exposure unit 26, the intermediate transfer belt 27, and the transfer unit 28 illustrated in FIG. 1 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 a corresponding image with magenta toner. The image forming unit 25C forms a corresponding image with cyan toner. The image forming unit 25K forms a corresponding 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 reusing paper and forms an erasable original image. As described above, the color of the decolorable 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 the paper is reused, but only the toner to be used is different and the configuration and operation are the same as those of the other image forming units.

  Hereinafter, image formation by the electrophotographic method will be described in detail. 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 of the original image acquired by the scanner unit 1 by 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 (1). Next 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 (for example, a portion where the photosensitive drum and the transfer belt are in contact). 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 using a decolorable 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.

  The transfer unit 28 includes a support roller 28 a and a secondary transfer roller 28 b provided along the conveyance path of the paper P. The transfer unit 28 transfers the toner image on the intermediate transfer belt 27 onto the paper P at the secondary transfer position. The secondary transfer position is a position where the support roller 28 a and the secondary transfer roller 28 b face each other with the intermediate transfer belt 27 interposed therebetween. 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 the paper P by a transfer bias. The system control unit 5 controls a transfer current used for the secondary transfer process.

  The fixing device 29 disposed on the downstream side of the transfer unit 28 has a function of fixing toner onto the paper P. For example, in the embodiment, the fixing device 29 fixes the toner image on the paper P by heat and pressure applied to the paper P.

  In the configuration example shown in FIGS. 1 and 5, the fixing device 29 includes a heat roller (heating unit) 29b having a built-in heating source 29a and a pressure roller (pressing unit) 29c that comes into contact with the pressure mechanism 29d in a pressurized state. It consists of. The heating source 29a may be a known temperature-controllable heater. For example, the heating source 29a may be configured by a lamp heater such as a halogen lamp, or may be an induction heating (IH) type heater. The heating source 29a may be composed of a plurality of heaters. As shown in FIG. 5, the fixing device 29 further includes a temperature sensor 29e for measuring the temperature of the heat roller 29b. The temperature sensor 29e transmits the measured temperature of the heat roller 29b to the system control unit 5 described later. The pressure mechanism 29d presses the pressure roller 29c to the heat roller 29b. The pressurizing mechanism 29d is configured by an elastic member or the like. When the pressure roller 29c is not pressed against the heat roller 29b by the pressure mechanism 29d, the pressure roller 29c and the heat roller 29b are separated from each other, and a gap is formed between them. The heat roller 29b is rotationally driven by the drive unit 29f. When the pressure roller 29c is pressed by the heat roller 29b, the pressure roller 29c is driven to rotate following the heat roller 29b. As shown in FIG. 5, the registration roller 24, the transfer unit 28, and the fixing device 29 are provided in this order as going downstream in the transport direction.

  When performing a fixing process for fixing the toner image on the paper P, the system control unit 5 controls the temperature of the fixing device 29 to be a predetermined fixing temperature. The fixing device 29 heats the sheet P 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 P. A well-known branching mechanism (not shown) disposed downstream of the fixing device 29 conveys the fixed paper P to either the paper discharge unit 30 or the ADU 31 in response to a user's processing request.

  When the paper P fixed by the fixing device 29 is discharged, the paper P is carried out to the paper discharge unit 30. When an image is also formed on the back surface of the paper P fixed by the fixing device 29, the paper P 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 paper P reversed by the switchback to the upstream side of the registration roller 24 and the reading unit 23.

  The operation panel 4 is a user interface. The operation panel 4 has various known input buttons and a display unit 4a having a touch panel 4b. The system control unit 5 controls the contents displayed on the display unit 4 a of the operation panel 4. In addition, the operation panel 4 outputs information input by the touch panel 4b or the input 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. This information is stored as print information in a predetermined area of the RAM 54 described later.

  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, the ROM 53, and the RAM 54 constitute the system control unit 5.

  The ROM 53 stores a program for operating the CPU 51 and a threshold value in advance. For example, it stores a fixing temperature that enables fixing of erasable toner and non-erasable toner.

  In the RAM 54, various memory areas such as an area for expanding a program executed by the CPU 51 and a work area serving as a work area for data processing by the program are dynamically formed. Information such as the number of printed sheets and the density input from the operation panel 4 is stored in the print information area. Moreover, as shown in FIG. 6, it has an image storage area for storing image information to be printed (the image storage area of the RAM 54 corresponds to a storage unit). The image information stored in the image storage area includes an image area I which is an area where an image is formed using toner and a blank area K where an image is not formed using toner. Image formation is performed based on the image information stored in the image storage area, and primary transfer is performed on the intermediate transfer belt 27. The image information stored in the image storage area is a print document transmitted from the outside through the external I / F 56 or an image of the paper P captured through the scanner unit 1.

  The RAM 54 has an image file as shown in FIG. This image file stores, in the image information stored in the image storage area, the ratio of the image area I which is an area where an image is formed using toner and the blank area K where an image is not formed using toner. Further, the RAM 54 has a print file. This print file stores information on the remaining area and blank area of the image of the paper P obtained by decoding the two-dimensional code of the identifier C. For this reason, the information stored in the print file is the same as the information shown in FIG.

  The HDD 55 is installed with an OS (Operating System) that operates the MFP 100. Further, as described above, in a predetermined area of the HDD 55, what type of paper is stored in each of the paper feed cassettes 20A, 20B, and 20C is stored. In addition, it has a non-reusable threshold value that is a threshold value indicating whether or not printing is performed using the paper P that is left unerased in the image stored in the paper cassette 20B. The non-reusable threshold stores the ratio of the blank area K. If the ratio of the blank area K stored in the image file in the RAM 54 is equal to or greater than the non-reusable threshold, the image to be printed has a lot of blank areas, so that there is an unerased residue stored in the paper cassette B. Control is performed to use paper P. Conversely, if the blank area K stored in the image file in the RAM 54 is equal to or less than the non-reusable threshold, it is determined that the image to be printed has a small blank area and the amount to be printed is large, and the image remaining in the paper cassette 20A remains unerased. Use no paper P. In the present embodiment, it is assumed that a value of 20% is stored as the non-reusable threshold. In other words, if the blank area K of the image information to be printed is 20% or less, there is a possibility that the printing amount is large and the sheet of the paper cassette 20B having the unerased image cannot be printed on one sheet. Paper that has not been reused is fed from the paper feed cassette 20A and printed.

The external I / F 56 is an interface for communicating with an external device. For example, the external I / F 56 is an external device such as a client terminal (PC),
The print data corresponding to the print request from is received. 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 a device (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 configuration of the scanner unit 1, the printer unit 2, and the operation panel 4 has been described above, the description thereof is omitted.

  In MFP 100 having the above configuration, MFP 100 executes the print job shown in FIG. 7 based on a preset program.

  When the MFP 100 performs a print job, it is assumed that a sheet P having an identifier C, a blank area K, and an unerased area N is already set in the paper feed cassette 20B of the paper feed unit as shown in FIG. . The paper feed cassette 20A stores paper P on which an image can be formed. Further, in the paper P fed from the paper cassette 20B, the upper (front) 30% of the paper is the remaining erasure area N, the 50% blank area K continues, and finally the 20% remaining erasure area is formed. It shall be. As shown in FIG. 4A, these pieces of information are stored in an identifier C that is a two-dimensional code. It is assumed that the operator presses the start key on operation panel 4 and MFP 100 starts a print job. Further, the MFP 100 reads the paper P placed on the scanner 1, and forms 30% of the image area I in the image storage area of the RAM 54 and the blank area K in the remaining 70% as shown in FIG. It is assumed that the generated image information is generated. In addition, it is assumed that a value of 20% is stored in the non-reusable threshold value of the HDD 55. This print job may be printed with a erasable toner or may be printed with a non-erasable toner. In this embodiment, it is assumed that printing is performed using a toner that cannot be erased.

  The system control unit 5 acquires the ratio of the image area I and the blank area K from the image information stored in the image storage area of the RAM 54, and stores it in the image file of the RAM 54 as shown in FIG. Then, the blank area K stored in the image file in the RAM 54 is compared with the non-reusable threshold stored in the HDD 55. That is, it is determined whether the blank area K stored in the image file in the RAM 54 is 20% or more (ACT 101). The ratio of the blank area K in the image storage area is obtained by analyzing image information in the image storage area by using OCR (Optical Character Reader) software or performing various processes such as macro recognition or micro recognition. The ratio of the image area I and the blank area K of the image information in the analyzed image storage area is stored in the image file of the RAM 54 (ACT 101).

  When the blank area K is less than or equal to the non-reusable threshold (the printing amount of the image to be printed is large, the blank area K of the image file is 20% or less) (No in ACT 101), the system control unit 5 The roller 21A is driven to pick up the paper P on which the image can be formed on the entire surface from the paper feed cassette 20A, which is the second placement unit, and starts transporting the paper P (ACT 110). Then, the image is transferred to the paper P and printed (ACT 111).

  On the other hand, when the blank area K is equal to or greater than the non-reusable threshold (the printing amount of the image to be printed is small. The blank area K of the image file is 20% or more) (Yes in ACT 101), the system control unit 5 Then, the pickup roller 21B is driven to pick up the unerased paper P from the paper feed cassette 20B, which is the first placement section, and starts conveying the paper P (ACT102).

  The system control unit 5 reads the identifier C formed on the paper P using the reading unit 23 in the process of transporting the paper P to the registration roller 24. The system control unit 5 conveys the paper P to the registration roller 24 and waits (ACT 103).

  The system control unit 5 determines whether or not the identifier P exists on the paper P (ACT 104). This is determined using OCR software or the like for the read image. When the system control unit 5 determines that the identifier P is not present on the paper P (ACT 104: Yes), the transfer unit 28 transfers the image stored in the image storage area of the RAM 54 to the paper P, and the fixing device 29 transfers the image to the paper P. The image is fixed on P and printed on paper P (ACT 111). Thereafter, the paper P is discharged from the paper discharge unit 30 (ATC 112).

  On the other hand, when the system control unit 5 determines that the identifier P exists on the sheet P (ACT 104: No), the two-dimensional code of the identifier C is decoded (ACT 105). By the processing of ACT 105, the system control unit 5 acquires the state of the sheet P in which the front 30% is the remaining erased area N, the blank area K is followed by 50%, and finally the erased remaining area is 20%. The acquired information is stored in a print file in the RAM 54.

  Then, it is determined whether the image area I of the image file fits in the blank area K of the print file, that is, “print file blank area K ≧ image file image area I”. In other words, it is determined whether the content to be printed on the paper P having the unerased image fits within one page 1 (ACT 106).

  If the system control unit 5 determines that “print file blank area K ≧ image file image area I” (Yes in ACT 106), only one page of image information stored in the image storage area as shown in FIG. Correct it. First, the remaining erase area N and the blank area K are read from the print file, and the print contents of the image storage area are printed in the blank area K. Then, the portion corresponding to the remaining erasure area is masked with black toner that cannot be erased, and the image information stored in the image storage area is corrected (ACT 107).

  Subsequently, the system control unit 5 drives the image forming unit 25, the exposure unit 26, the intermediate transfer belt 27, the transfer unit 28, and the registration roller 24 to transfer the image onto the paper P. When the transfer of the image to the paper P is completed, the image information that has been transferred is deleted from the image storage area of the RAM 54. Thereafter, the paper P is conveyed to the fixing device 29, and the image formed on the paper P is fixed (ACT 111). Then, the fixed image is printed and discharged to the discharge unit 30 (ACT 112).

  On the other hand, if the system control unit 5 determines that “the blank area K of the print file <the image area I of the image file” (No in ACT 106), the entire image information stored in the image storage area of the RAM 54 is corrected. FIG. 9 will be described as an example. Before the correction, it is assumed that an image in which the image area I is 80% and the blank area K is 20% is stored in the image storage area of the RAM 54. Then, when this image is to be printed on the paper P on which the front 30% is the remaining erasure area N, followed by 50% blank area K, and finally 20% erasure remaining area is formed, Since the blank area of P is 50% and the image area I of the image file is 80%, the blank area is insufficient. The paper P is moved by the amount that can be inserted into the blank area K of the paper P among the image information described in the image area I, and the image information that cannot be inserted is newly created for the second page. . The image information for the second page is created assuming that the image area I is 100%. Similarly to the above-described ACT 107, the remaining erase area N is masked with black toner that cannot be erased (ACT 108). When the correction of the image information is completed, the number of prints in the print information area of the RAM 54 is increased by 1 (ACT 109). Then, the system control unit 5 drives the image forming unit 25, the exposure unit 26, the intermediate transfer belt 27, the transfer unit 28, and the registration roller 24 to transfer the first image onto the paper P. When the transfer of the image to the paper P is completed, the image information of the first sheet that has been transferred is deleted from the image storage area of the RAM 54. Thereafter, the paper P is conveyed to the fixing device 29, and the image formed on the paper P is fixed (ACT 111). Then, the fixed image is printed and discharged to the discharge unit 30 (ACT 112).

  After discharging the paper P to the paper discharge unit 30, the system control unit 5 determines whether image information to be printed exists in the image storage area of the RAM 54 (ACT 113). When image information exists in the image storage area of the RAM 54 (No in ACT 113), the process returns to ACT 101 again. On the other hand, if there is no image information in the image storage area of the RAM 54 (Yes in ACT 113), the print job is terminated.

  As described above, an image can be formed in a still usable area of the paper on which the image has been erased, so that conventionally discarded paper can also be used efficiently. For images with a large amount of printing, the entire surface is fed by checking the amount of printing before feeding, so two sheets of printable material can be printed. Can be reduced.

  In the embodiment of the present invention, the ratio of the blank area K is stored in the non-reusable threshold, but the ratio of the image file I may be stored.

  In the embodiment of the present invention, the ratio of the blank area K and the remaining erasure area N is stored in the identifier C. However, at least one of them may be stored. This is because if the blank area K is known, the remaining area can be determined as the remaining erase area N.

  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 (4)

The formed image is erased, and a first placement unit for placing a sheet having an identifier for storing at least one of a blank area or an unerased area of the sheet, and a sheet on which an image can be formed are placed on the entire surface. A paper feed unit having a second placement unit;
An image area that is an area for forming an image using toner, and a storage unit that stores image information including a blank area that does not form an image using toner ;
An image forming unit that forms an image based on image information stored in the storage unit;
A reading unit that is provided upstream of a position where the image forming unit forms an image on a sheet and reads an identifier of the sheet fed by the sheet feeding unit;
If the ratio of the blank area of the image information stored in the storage unit is equal to or greater than a non-reusable threshold that is a threshold for printing using the paper placed on the first placement unit, the second placement is performed. feeds the placed paper portion, feeding the paper fraction of blank region is placed on the first placement unit if less than nonreusable threshold of the image information stored in the storage unit A control unit for determining a blank area of the paper based on the identifier read by the reading unit and correcting the image information of the storage unit so that an image is formed in the blank area of the paper;
An image forming apparatus. The control unit determines a blank area of the sheet based on the identifier of the sheet read by the reading unit, and if the print area of the image information stored in the storage unit is larger than the blank area of the sheet The image forming apparatus according to claim 1, wherein when the determination is made, the image information stored in the storage unit is divided into a plurality of pieces and corrected. The control unit is configured to determine a remaining erase area of the sheet based on the identifier of the sheet read by the reading unit, and to control the image information of the storage unit so as to mask the remaining erase area. The image forming apparatus according to claim 1 or 2. The control unit controls the image forming unit to form an image based on the image information on the sheet without correcting the image information in the storage unit when the sheet is fed from the second placement unit. I do
The image forming apparatus according to claim 1.

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