JP2014068297A - Image forming apparatus and image reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus and an image reading method capable of effectively reducing set-off without causing complexity in configuration of the apparatus and an increase in costs.SOLUTION: A compound machine MF as an image forming apparatus includes: an image reading device 1 that reads an image of a document; an image forming unit 50 that forms an image according to the image read by the image reading device 1 on a sheet; and an image processing unit 72 that performs processing to reduce a set-off image included in the image read by the image reading device 1 in the degree according to the type of the sheet used for formation of the image by the image forming unit 50.

Description

  The present invention relates to an image forming apparatus and an image reading method.

  In recent years, in order to effectively use resources and reduce costs, there has been an increase in the chance of reusing paper (so-called backing paper) on which one side has been printed and the remaining side has not been printed. When such a backing paper is reused, the unprinted side will also be printed, which inevitably increases the number of double-sided printed documents, and as a result the opportunity to read the images of double-sided printed documents Will also increase. For example, this is a case where one or both sides of a double-side printed document are copied using an image forming apparatus such as a copying machine or a multifunction machine.

  The image forming apparatus includes an image reading device that is generally called a scanner, and optically reads an image of a document (document) by the image reading device. Therefore, depending on the type of document, there is a possibility that a phenomenon (so-called show-through) occurs in which an image in which an image on another surface is reflected is read with respect to an image on a surface to be read. The following Patent Documents 1 to 5 disclose techniques for eliminating or reducing such show-through.

  Specifically, the following Patent Document 1 discloses a technique for detecting the paper quality of a document to be read by a dedicated sensor and correcting the density according to the detection result. Patent Document 2 below discloses a technique for obtaining a show-through amount from the result of reading both sides of a document and removing the show-through based on the show-through amount. In the following Patent Documents 3 to 5, the background density of the original to be read (for example, the color density of the paper itself such as newspaper or colored paper) is detected, and background removal (tone correction) is performed according to the detection result. Technology is disclosed.

Japanese Patent Laid-Open No. 5-56257 JP-A-6-62216 Japanese Patent Laid-Open No. 7-273395 JP 7-322069 A Japanese Patent Laid-Open No. 7-74952

  By the way, although it is thought that the technique disclosed by the patent documents 1-5 mentioned above can eliminate or reduce show-through, there exists a problem shown below. The technique disclosed in Patent Document 1 described above requires a dedicated sensor for detecting the paper quality of the document, and thus there is a problem that the configuration of the apparatus is complicated and the cost is increased. Further, the technique disclosed in Patent Document 2 described above has a problem that it takes a long time to read because it is necessary to read both sides of the document in order to obtain the show-through amount.

  In addition, the techniques disclosed in Patent Documents 3 to 5 described above eliminate or reduce show-through by adjusting the background removal amount, and effectively eliminate or reduce show-through as the background removal amount increases. can do. However, when there is no show-through, wasteful processing related to background removal is performed even though it is not necessary to perform background removal. For example, FCOT (First Copy Output Time: copy button (start button) The time from when the button is pressed until the first printed sheet comes out may be affected. Further, if the background removal amount is increased, the show-through can be effectively eliminated or reduced, but other than the show-through (for example, the pattern on the surface to be read) is also removed. .

  The present invention has been made in view of the above circumstances, and provides an image forming apparatus and an image reading method capable of effectively reducing show-through without increasing the complexity of the apparatus and increasing costs. For the purpose.

In order to solve the above problems, an image forming apparatus according to the present invention includes an image reading unit that reads an image of a document, and an image forming unit that forms an image corresponding to the image read by the image reading unit on a sheet. In the image forming apparatus, an image processing unit that performs a process of reducing a show-through image included in the image read by the image reading unit to a degree according to the type of paper used for image formation by the image forming unit. It is characterized by providing.
The image forming apparatus of the present invention further includes a setting unit capable of setting a type of paper used for forming an image by the image forming unit, and the image processing unit is configured to perform the setting based on the setting of the setting unit. It is characterized by changing the degree of reducing the show-through image.
Further, in the image forming apparatus of the present invention, the setting unit can set the density of the back side of the document read by the image reading unit, and the image processing unit can determine the type of paper set by the setting unit. The degree of reducing the show-through image is changed based on the density of the back side of the document.
In the image forming apparatus of the present invention, the degree of reduction of the show-through image is registered in advance for each paper type, and can be switched according to the paper type set in the setting unit. Yes.
In the image forming apparatus of the present invention, the degree of reduction of the show-through image can be registered by causing the image reading unit to read an image of a sheet used for forming an image by the image forming unit. It is a feature.
In the image forming apparatus of the present invention, the sheet on which the image reading unit reads an image has a test pattern printed on the back surface of the surface to be read.
The image forming apparatus of the present invention is characterized in that the test pattern has a plurality of patterns having different widths and densities.
An image reading method of the present invention uses an image forming apparatus that includes an image reading unit that reads an image of a document and an image forming unit that forms an image corresponding to the image read by the image reading unit on a sheet. An image reading method for reading, comprising: a first step of setting a type of paper used for forming an image by the image forming unit; and a paper used for forming an image by the image forming unit and printed on both sides And reducing the show-through image included in the image read in the second step to a degree corresponding to the type of paper set in the first step And a third step for performing the processing.

  According to the present invention, there is an effect that the show-through can be effectively reduced without complicating the apparatus configuration and increasing the cost.

1 is a front perspective view showing an overall configuration of a multifunction machine as an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating a main configuration of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. It is a figure which shows an example of the paper used when registering the reduction degree of show-through in one Embodiment of this invention. FIG. 2 is a diagram illustrating an operation display unit of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. 5 is a flowchart illustrating an operation of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention.

  Hereinafter, an image forming apparatus and an image reading method according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the image forming apparatus is described as an example of a multifunction device having both a copy function, a print function, and a facsimile transmission / reception function. FIG. 1 is a front perspective view showing the overall configuration of a multifunction machine as an image forming apparatus according to an embodiment of the present invention. As shown in FIG. 1, the multi-function device MF includes an image reading device 1 (image reading unit) and a multi-function device main body 2, and performs image formation according to an image read by the image reading device 1.

  The image reading apparatus 1 includes a scanner 10 and an ADF (Auto Document Feeder) 20 and reads an image of a document. The scanner 10 includes a platen glass 11, a white reference plate 12, a full rate carriage 13, a half rate carriage 14, a condenser lens 15, and a CCD (Charge Coupled Device) sensor 16. Reading of a set document or a document automatically fed by the ADF 20 is performed.

  The platen glass 11 is a glass plate for setting originals to be read one by one. The white reference plate 12 is a white plate for acquiring white reference data for shading correction. The full-rate carriage 13 includes a lamp 13 a that emits illumination light obliquely upward, and a mirror 13 b that reflects reflected light of the illumination light toward a half-rate carriage 14 described below, and below the platen glass 11. In FIG. 3, the carriage is provided so as to be capable of reciprocating in the horizontal direction (scanning direction) along the platen glass 11 by a carriage conveyance mechanism (not shown).

  The half-rate carriage 14 includes a mirror 14a that reflects light from the mirror 13b of the full-rate carriage 13 downward, and a mirror 14b that reflects light reflected by the mirror 14a toward the condenser lens 15. Similarly to the full rate carriage 13, the carriage is provided so as to be reciprocally movable in the left-right direction along the platen glass 11 by a carriage conveyance mechanism (not shown). The ratio of the movement amount of the full-rate carriage 13 and the movement amount of the half-rate carriage 14 is controlled by the carriage conveyance mechanism to be 1: 0.5. Thereby, the optical path length of the illumination light until reaching the condenser lens 15 is controlled to be constant.

  When reading an original set on the platen glass 11, the original image is read while moving the full-rate carriage 13 and the half-rate carriage 14 in the scanning direction. On the other hand, when reading a document automatically fed by the ADF 20, the full-rate carriage 13 and the half-rate carriage 14 are kept waiting at a predetermined document reading position, and images of the document continuously conveyed by the ADF 20 are stored. Are read sequentially.

  The condensing lens 15 condenses the light from the mirror 14 b of the half rate carriage 14 and forms an image on the light receiving surface of the CCD sensor 16. The CCD sensor 16 operates in synchronization with a timing signal supplied from a CCD drive unit (not shown), and photoelectrically converts the light imaged on the light receiving surface to generate an analog voltage signal corresponding to the read document image. Generate and output to AFE (analog front end: not shown). The AFE amplifies the analog voltage signal with a predetermined gain setting value and then digitally converts it to generate image data representing the read document image, and the generated image data is controlled by the MFP main body 2. It outputs to the part 70 (refer FIG. 2).

  The ADF 20 includes a platen cover 21, a document placement tray 22, a pickup roller 23, a registration roller 24, a platen roller 25, a paper discharge roller 26, and the like, and a plurality of documents set on the document placement tray 22. Automatically feeds one sheet at a time. The platen cover 21 is provided so as to be openable and closable with respect to the upper surface of the scanner 10. The platen cover 21 serves as a document pressing cover when a document is set on the platen glass 11 for reading, and a pickup roller 23 and a registration roller 24. The platen roller 25, the paper discharge roller 26, and the like serve as housing cases for members used in the automatic paper feeding mechanism. FIG. 1 shows a state in which the platen cover 21 is closed.

  The document placing tray 22 is a tray for setting a document to be read. The pickup roller 23 is a roller for picking up documents set on the document placing tray 22 one by one and carrying them out to the registration roller 24. The registration roller 24 is a roller for conveying the document to the platen roller 25 at a predetermined timing. The platen roller 25 is a roller for transporting the document to the paper discharge roller 26 via a predetermined document reading position. The paper discharge roller 26 is a roller for discharging the original after reading to the outside. The rotation operation of each of these rollers is controlled by the control unit 70 of the multifunction machine main body 2.

  The multifunction device main body 2 includes a paper storage unit 30, a paper transport unit 40, an image forming unit 50, a fixing unit 60, and the like, depending on image data from the image reading apparatus 1 or image data transmitted from the outside. The image is formed. The multi-function device main body 2 includes an openable and closable manual feed tray Tr on the left side in the drawing, so that the paper (printing paper) placed on the manual feed tray Tr can be transported by the paper transport unit 40. Yes.

  When the image data from the image reading apparatus 1 or image data transmitted from the outside is RGB color space data, the multi-function device body 2 converts the image data into CMYK color space data. As is well known, the RGB color space data is a digital value indicating a gradation value of a pixel (minimum unit constituting an image) corresponding to each of the three primary colors R (red), G (green), and B (blue). It is data. Also, the CMYK color space data refers to the three primary colors of C (cyan), M (magenta), and Y (yellow) for printing (toner in the multifunction machine MF) and K (key plate: black coloring). This is data that represents an image by adding. The MFP main body 2 individually forms CMYK color toner images corresponding to the image to be formed, and superimposes these color toner images to form a color toner image corresponding to the image to be formed.

  The paper storage unit 30 includes paper feed cassettes 31a, 31b, and 31c that store paper of various sizes. Each of the paper feed cassettes 31a, 31b, and 31c can accommodate a plurality of sheets (for example, about several tens of sheets), and is disposed at the bottom of the multifunction machine main body 2 so that it can be pulled out from the front of the multifunction machine main body 2. Has been. Note that the number of paper feed cassettes is not limited to three, and at least one is sufficient.

  The paper transport unit 40 includes pickup rollers 41a, 41b, and 41c, paper feed rollers 42a, 42b, and 42c, a paper discharge roller 43, and the like, and is accommodated in the paper feed cassettes 31a, 31b, and 31c of the paper storage unit 30. Or the sheet placed on the manual feed tray Tr is conveyed. The pickup rollers 41a, 41b, and 41c are rollers for feeding out the uppermost sheet among the sheets stored in the sheet feeding cassettes 31a, 31b, and 31c toward the sheet feeding rollers 42a, 42b, and 42c, respectively. . The paper feed rollers 42a, 42b, and 42c are rollers for transporting the paper fed by the pickup rollers 41a, 41b, and 41c to the image forming unit 50. The paper discharge roller 43 is a roller for discharging (outputting) the paper after the fixing process by the fixing unit 60 to the outside as a printed matter.

  The image forming unit 50 includes an intermediate transfer belt 51, an image forming unit 52 (52Y, 52M, 52C, 52K), a driving roller 53, a tension roller 54, a secondary transfer roller 55, and a cleaner 56, and should be printed. A toner image corresponding to the image is formed, and the formed toner image is transferred to a sheet conveyed by the sheet conveying unit 40. The intermediate transfer belt 51 is an intermediate transfer body on which toner images of respective colors formed (developed) by the image forming unit 52 (52Y, 52M, 52C, 52K) are sequentially transferred (primary transfer). This intermediate transfer belt 51 is stretched around a drive roller 53 and a tension roller 54, and rotates clockwise in FIG.

  The image forming unit 52 (52Y, 52M, 52C, 52K) includes a photosensitive drum Fa, a charging unit Fb, an exposure unit Fc, a developing unit Fd, and a primary transfer roller Fe, and corresponds to an image to be printed. Each color toner image is formed. Although not shown in FIG. 1, the image forming unit 52 (52Y, 52M, 52C, 52K) includes a cleaning device, a charge removal device, and the like.

  The photoconductor drum Fa is a cylindrical photoconductor on which an electrostatic latent image corresponding to an image to be printed is formed and which carries a developed toner image. The charging unit Fb is disposed so as to face the photosensitive drum Fa and charges the peripheral surface of the photosensitive drum Fa. The exposure unit Fc irradiates the photosensitive drum Fa with laser light for forming an electrostatic latent image corresponding to the image data. The developing unit Fd develops the electrostatic latent image into a toner image by supplying toner to the photosensitive drum Fa on which the electrostatic latent image is formed by irradiation of laser light from the exposure unit Fc.

  The primary transfer roller Fe is disposed to face the photosensitive drum Fa with the intermediate transfer belt 51 interposed therebetween, and primarily transfers the toner image carried on the photosensitive drum Fa to the intermediate transfer belt 51. The secondary transfer roller 55 is disposed opposite to the driving roller 53 with the intermediate transfer belt 51 interposed therebetween, and supplies a toner image (a toner image of each color superimposed) transferred to the intermediate transfer belt 51. Secondary transfer is performed on the paper transported by the paper transport unit 40 from any of the paper cassettes 31a, 31b, and 31c (or from the manual feed tray Tr). The cleaner 56 includes a cleaning roller, a cleaning blade, and the like, and removes residual toner on the intermediate transfer belt 51.

  The fixing unit 60 includes a heating roller 61, and heats and pressurizes the sheet (the sheet onto which the toner image is transferred) conveyed by the sheet conveying unit 40, thereby transferring the toner image transferred to the sheet to the sheet. To settle. The heat generation temperature of the heating roller 61 (that is, the fixing temperature of the fixing unit 60) is controlled by the control unit 70 described later. The sheet on which the toner image is fixed by the fixing unit 60 is discharged to the outside of the multifunction machine main body 2 by the sheet discharge roller 43 of the sheet transport unit 40.

  FIG. 2 is a block diagram illustrating a main configuration of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. In FIG. 2, components corresponding to those shown in FIG. As shown in FIG. 2, the multifunction machine MF includes a control unit 70, an image data storage unit 71, and an image processing unit in addition to the image reading device 1 and the sheet conveying unit 40, the image forming unit 50, and the fixing unit 60 described above. 72, an operation display unit 73 (setting unit), and a communication I / F unit 74. The control unit 70, the image data storage unit 71, the image processing unit 72, the operation display unit 73, and the communication I / F unit 74 are provided in the MFP main body 2.

  The control unit 70 controls the operation of the multifunction machine MF in accordance with operation instructions input from the operation display unit 73 or various instructions input from the communication I / F unit 74. For example, image data reading control by the image reading apparatus 1, image data reception control in the communication I / F unit 74, or printing control of image data stored in the image data storage unit 71 is performed. The control unit 70 is realized by, for example, a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface.

  The image data storage unit 71 is realized by, for example, a hard disk device, and stores various data under the control of the control unit 41. For example, image data output from the image reading apparatus 1 when a document is read, image data transmitted via a network (not shown) and received by the communication I / F unit 74, or an image processing unit 72 The image data subjected to the image processing is stored.

  The image processing unit 72 is image data output from the image reading apparatus 1, image data received by the communication I / F unit 74, or an image stored in the image data storage unit 71 under the control of the control unit 70. Various image processing is performed on the data. For example, when the image data is RGB color space data, the image data is converted into CMYK color space data. Also, image data compression / decompression processing, image data printing rate calculation processing, and the like are performed.

  Further, the image processing unit 72 performs processing for reducing the show-through image included in the image with respect to the image data obtained from the image reading device 1. When this processing is performed, the image processing unit 72 shows the show-through image at a degree corresponding to the type of paper (or paper placed on the manual feed tray Tr) stored in the paper feed cassettes 31a, 31b, 31c. Process to reduce the. This is a show-through that occurs when the image reading apparatus 1 reads an image of a recycled backing paper (a sheet on which one side is printed by the multifunction machine MF and then the remaining side is printed by the multifunction machine MF). This is because the device configuration can be effectively reduced without complicating the device configuration and increasing costs.

  Specifically, the image processing unit 72 changes the degree of reducing the show-through based on the content of “paper setting” performed by the user or service person operating the operation display unit 73. This “paper setting” is to change the transfer and fixing settings according to the paper used so that the state of the transfer of the toner image to the paper and the fixing of the toner image to the paper at the time of printing is optimized. Here, the show-through depends on the light transmittance of the paper (that is, the quality and thickness of the paper) and changes depending on the type of paper used. Further, it is considered that most of the originals in which the show-through occurs is reused. For this reason, the degree of reduction of the show-through is changed in conjunction with the “paper setting” described above.

  Further, the degree of show-through varies depending on the content printed on the back side (specifically, the density of the back side) in addition to the type of paper. For example, when many fine lines are printed, such as when characters are printed, or when light color printing is performed, the degree of show-through is low due to the low density of the back side (not much Does not appear). On the other hand, when many thick lines are printed as in the case where a graphic is printed, or when a dark color is printed, the degree of show-through is high because the density on the back surface is high (the back side Easy to capture). For this reason, the image processing unit 72 shows-through based on the setting contents of the above-mentioned “paper setting” and the setting contents of “the density of the back side of the document” that the user or serviceman operates by operating the operation display unit 73. Change the degree to reduce.

  Here, the degree to which the show-through is reduced by the “paper setting” is registered in advance for each main paper type, and the content of the “paper setting” performed by the user or the like by operating the operation display unit 73. Switch based on. Further, in the case of a sheet on which the degree of show-through reduction is not registered, the sheet can be registered by causing the image reading apparatus 1 to read the image of the sheet on which the test pattern shown in FIG. 3 is printed. .

  FIG. 3 is a diagram showing an example of a sheet used when registering the degree of reduction of show-through in an embodiment of the present invention, and (a) is a diagram showing a surface on which a test pattern is printed, (B) is a figure which shows the back surface. As shown in FIG. 3, the test pattern P has a plurality of patterns having different widths and densities. Specifically, the test pattern P illustrated in FIG. 3 has three linear patterns P1 with different densities (for example, a width of several millimeters) and wide patterns with different densities (for example, 5 to 10). And three linear patterns P2 having a width of about millimeters). Such a test pattern may be provided for each color (C, M, Y, K).

  The degree of show-through reduction can be registered, for example, by the following procedure. First, using the multifunction machine MF, the test pattern P shown in FIG. 3 is printed on the surface of a sheet (a sheet on which the degree of the show-through image is not registered). Next, the paper on which the test pattern P is printed is turned over, and the image on the back side (the back side image shown in FIG. 3B) on which the test pattern P is not printed is read by the image reading device 1. Then, the control unit 70 determines the density level of the show-through image included in the image read by the image reading apparatus 1, and determines the reduction level of the show-through in a plurality of stages (for example, five stages) according to the density level. To do. By registering the determined degree of show-through reduction in “paper setting”, it is possible to reduce show-through suitable for the paper actually used.

  The operation display unit 73 includes an operation key unit 73a and a display unit 73b. The operation display unit 73 inputs an instruction corresponding to a user operation and displays various types of information such as information indicating the state of the multifunction machine MF. The communication I / F unit 74 is connected to a network (not shown), and transmits / receives various signals to / from a terminal device (not shown) via the network.

  FIG. 4 is a diagram illustrating an operation display unit of a multifunction peripheral as an image forming apparatus according to an embodiment of the present invention. As shown in FIG. 4, the operation key unit 73a includes hard keys such as a start key, a stop / clear key, a power key, a numeric keypad (numerical value input key), and a function switching key. The function switching key is used to switch the MFP MF to the operation mode of each function when the user uses each of the copy function, print function, scan function, and facsimile function realized by the MFP MF. Key. The display unit 73b has a touch panel function, and displays a screen including soft keys. The key for performing the “paper setting” described above is displayed as a soft key on the display unit 73b.

  Next, the operation of the multifunction machine MF having the above configuration will be described. In the following, an operation in the case of copying an image of one side (a side printed later) of the reused backing paper will be described. FIG. 5 is a flowchart showing the operation of the multifunction machine as the image forming apparatus according to the embodiment of the present invention. Note that the processing of the flowchart shown in FIG. 5 is started, for example, when the copy function switching key provided in the operation display unit 73 is operated by the user and the copy function is enabled.

  First, the user sets a document to be copied (reused backing paper) on the document placing tray 22 of the ADF 20. At this time, the document is set on the document placing tray 22 so that the surface on which the image is read (the surface printed later) faces upward. Next, a process of setting the paper type (“paper setting”) according to the operation of the operation display unit 73 by the user is performed (step S11: first step). Specifically, the user performs an operation of selecting any one of the paper feed cassettes 31a, 31b, and 31c provided in the multi-function peripheral MF, so that the sheets stored in the selected paper feed cassette can be selected. Processing to set the type is performed.

  Next, a process of setting the density of the back side of the document according to the operation of the operation display unit 73 by the user is performed (step S12). Here, for the density setting, for example, the user designates a numerical value indicating the density (for example, a numerical value in the range of 0 to 100%), and the user sets a predetermined density category (for example, “dark”, “slightly dark”). , “Ordinary”, “slightly thin”, “thin”, etc.), or the user selects a predetermined document category (eg, “text”, “figure”, “photograph”, etc.) .

  When the above setting is completed, the control unit 70 determines whether or not the user has pressed the start key of the operation display unit 73 (step S13). When it is determined that the start key is not pressed (when the determination result is “NO”), the process of step S13 is repeated. On the other hand, when it is determined that the start key has been pressed (when the determination result is “YES”), the image reading apparatus 1 is controlled by the control unit 70, and the document set on the document placement tray 22 is detected. While being automatically fed by the ADF 20, the scanner 10 reads an image of the automatically fed document (step S14: second step).

  When the image of the original is read, image data corresponding to the read image is output from the image reading apparatus 1 to the control unit 70 provided in the multifunction machine main body 2. The image data is output from the control unit 70 to the image processing unit 72, and a process of reducing a show-through image included in the image (a process of reducing show-through) is performed (step S15: third step). Here, the show-through reduction processing is performed according to the type of paper set in step S11 and the density of the back side of the document set in step S12.

  The image data on which the show-through reduction processing has been performed is temporarily stored in the image data storage unit 71 by the control unit 70, then read out again to the control unit 70 and sent to the image forming unit 50. If it is not necessary to store the image data in the image data storage unit 71, the image data that has undergone the show-through reduction process may be sent directly to the image forming unit 50.

  When the image data that has undergone the show-through reduction process is input to the image forming unit 50, an image corresponding to the image data is printed on a sheet (step S16). Specifically, the conveyance of the sheet (the type of sheet set in step S11) is started by the sheet conveying unit 40, and the formation of the toner image corresponding to the image data on which the show-through reduction processing has been performed is performed. Started by the forming unit 50. When the toner image is formed by the image forming unit 50, the toner image is transferred and fixed on the sheet conveyed by the sheet conveying unit 40. The printing paper on which the toner image is fixed is transported by the paper transporting unit 40 and discharged to the outside of the multifunction machine main body 2. In this way, the recycled backing paper is copied.

  As described above, in the present embodiment, the process of reducing the show-through image included in the image read by the image reading device 1 is performed according to the type of paper used for image formation by the image forming unit 50. This is performed by the processing unit 72, and the degree to reduce the show-through is changed in conjunction with the “paper setting”. For this reason, the show-through can be effectively reduced without complicating the apparatus configuration and increasing the cost.

  The image forming apparatus and the image reading method according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, in order to facilitate understanding, an example in which the setting of the paper type and the density on the back side of the document are set when reading the document has been described (steps S11 and S12 in FIG. 5). However, it is troublesome to make the above setting every time the document is read. For this reason, a sheet that is frequently used is set as a standard sheet in advance, and the density of a document that is frequently read is set as a standard density in advance. When is not designated, processing to reduce the show-through image may be performed according to the standard paper and the standard density.

  In the above-described embodiment, the case where the image forming apparatus according to the present invention is a multifunction machine has been described as an example. However, the present invention corresponds to the image reading apparatus 1 such as a copying machine or a facsimile, and the image forming unit 50. The present invention can also be applied to an image forming apparatus having such a configuration.

DESCRIPTION OF SYMBOLS 1 Image reader 50 Image forming part 72 Image processing part operation instruction 73 Operation display part MF MFP P Test pattern

Claims (8)

An image forming apparatus comprising: an image reading unit that reads an image of a document; and an image forming unit that forms an image according to an image read by the image reading unit on a sheet.
An image processing unit that performs processing for reducing a show-through image included in an image read by the image reading unit to a degree according to the type of paper used for image formation by the image forming unit. Image forming apparatus. A setting unit capable of setting a paper type used for image formation by the image forming unit;
The image forming apparatus according to claim 1, wherein the image processing unit changes a degree of reducing the show-through image based on a setting of the setting unit. The setting unit can set the density of the back side of the document read by the image reading unit,
3. The image forming apparatus according to claim 2, wherein the image processing unit changes a degree of reducing the show-through image based on a paper type set by the setting unit and a density on the back side of the document. .   The degree of reducing the show-through image is registered in advance for each paper type, and is switched according to the paper type set by the setting unit. Image forming apparatus.   5. The degree of reduction of the show-through image can be registered by causing the image reading unit to read an image of a sheet used for forming an image by the image forming unit. The image forming apparatus according to any one of the above.   6. The image forming apparatus according to claim 5, wherein the sheet on which the image reading unit reads an image has a test pattern printed on the back surface of the surface to be read.   The image forming apparatus according to claim 6, wherein the test pattern includes a plurality of patterns having different widths and densities. An image reading method for reading an image using an image forming apparatus including an image reading unit that reads an image of a document and an image forming unit that forms an image corresponding to the image read by the image reading unit on a sheet,
A first step of setting a type of paper used for image formation by the image forming unit;
A second step of causing the image reading unit to read as a document a sheet used for image formation by the image forming unit and printed on both sides thereof;
And a third step of performing a process of reducing a show-through image included in the image read in the second step to a degree according to the type of paper set in the first step. Reading method.