JP2007188014A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique capable of securely avoiding reversed imaging even when various kinds of recording paper are utilized in an image forming apparatus reading an image of an original and forming the read image on the recording paper. <P>SOLUTION: The image forming apparatus comprises a test image output 201 for forming a test image 211f on the recording paper (recording paper R1 or recording paper R2); a back surface image acquisition 202 for reading the back surface image 211b emerging on the back surface of the recording paper by the reversed imaging of the test image 211f; a reversed imaging characteristic specifier 203 for associating the density of the image formed on the recording paper with the density of reversed imaging on the back surface of the recording paper generated by the image having the density, on the basis of the densities of the test image 211f and the corresponding part of the back surface image 211b; and a recording paper automatic selector 403 and a recording paper selection inquirer 402 for determining the recording paper for forming the original image, on the basis of the density emerging on the original image and the association relationship given by the reversed imaging characteristic specifier 203. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that reads an image of a document and forms the read image on a recording sheet.

  Conventionally, an image forming apparatus such as a printer, a copier, a FAX, or a multifunction peripheral has been used. In the image forming apparatus, the content printed on one side shows off on the back side, making it difficult to read the regular printed content on the back side, or even if regular printing is not performed on the back side. There are times when it ends up.

In order to avoid such show-through, the image forming apparatus described in Patent Document 1 stores data such as thickness for each type of recording paper (plain paper, glossy paper, special paper,...) By avoiding show-through by predicting show-through based on.
JP 2004-110585 A

  However, in the conventional technique disclosed in Patent Document 1, it is necessary to prepare a large number of data such as the thickness of the recording paper necessary for prediction for each type of recording paper. There are various types of recording papers used by users including those made by third parties, and new types of recording papers appear one after another as new products. Under such circumstances, it is not possible to prepare data for all types of recording paper. With the technology described in Patent Document 1, it is possible to accurately predict and avoid show-through reliably. There wasn't.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a technique that can reliably prevent show-through even when various types of recording paper are used.

  The invention according to claim 1 is an image forming apparatus that reads an image of a document and forms the read image on a recording paper, a test image forming unit that forms a predetermined test image on the recording paper, and a test image Is a show-through image acquisition means for reading a show-through image appearing on the back side of the recording paper, and the density of the image formed on the recording paper based on the density of the corresponding portion of the test image and the show-through image. Based on the correspondence specifying unit that associates the density of the show-through generated on the back side of the recording paper with the image of the density, and the correspondence that the density specified in the image of the document and the correspondence specifying unit attach the image of the document. An image forming apparatus comprising: a determining unit that determines a recording sheet to be formed.

  According to this configuration, a predetermined test image is formed on the recording paper, and a show-through image in which the test image appears on the back side of the recording paper is read. Then, based on the density of the corresponding portion of the test image and the show-through image, the density of the image formed on the recording paper is associated with the density of the show-through generated on the back side of the recording paper. The recording paper on which the original image is formed is determined based on the density appearing in the original image and the corresponding relationship.

  Therefore, even if various types of recording paper are used, a predetermined test image is formed on the recording paper, and the show-through image on which the test image appears on the back side of the recording paper is read, and the test Based on the density of the corresponding part of the image and the show-through image, the density of the image formed on the recording paper is correlated with the density of the show-through generated on the back side of the recording paper by the image of the density. The recording paper on which the image of the document is to be formed is determined based on the density shown in FIG. As a result, show-through can be reliably avoided even when various types of recording paper are used.

  The correspondence specifying unit may associate the density of the image formed on the recording paper with a certain range of density of the show-through caused by the density image on the back side of the recording paper.

  The invention according to claim 2 is characterized in that the correspondence specifying unit associates the density of the image formed on the recording paper with the presence or absence of show-through caused by the image of the density on the back surface of the recording paper. The image forming apparatus according to 1.

  According to this configuration, the density of the image formed on the recording paper is associated with the presence or absence of show-through caused by the image having the density on the back surface of the recording paper.

  Therefore, based on the density appearing on the original image and the correspondence relationship given by the correspondence specifying unit, when no show-through occurs on the recording paper, the recording paper is determined as the recording paper on which the original image is formed. Can do.

  According to a third aspect of the present invention, a plurality of sets of correspondence types stored by the correspondence specifying unit based on the density of the show-through image appearing on the recording paper of the type are stored in association with each other. A storage unit, wherein the determining means is based on the density appearing in the image of the document and each stored correspondence, and the most original of the types of recording paper stored in association with each correspondence An output recording paper automatic determination unit that selects one type determined to be suitable for forming the image and determines the type of recording paper as the recording paper on which the original image is to be formed. The image forming apparatus according to claim 1 or 2.

  According to this configuration, a plurality of sets of the types of recording paper and the correspondence relationships added by the correspondence specifying unit based on the density of the show-through image appearing on the type of recording paper are stored in association with each other. Then, based on the density appearing in the original image and each stored correspondence, it is most suitable for forming the original image among the types of recording paper stored in association with each correspondence. One type to be judged is selected, and this type of recording paper is determined as the recording paper on which the original image is formed.

  Therefore, the optimum recording paper among the various types of recording paper can be automatically selected as the recording paper on which the original image is formed.

  According to the fourth aspect of the present invention, a plurality of sets of correspondence types are stored in association with the types of recording paper and the correspondences assigned by the correspondence specifying unit based on the density of the show-through image appearing on the type of recording paper. And further comprising a storage unit, wherein each of the types of recording paper stored in association with each correspondence relationship stores the image of the document based on the density appearing in the document image and each correspondence relationship stored. An evaluation presentation unit that evaluates whether or not it is suitable for formation, and presents an evaluation result to the user, and obtains a user input of the user according to the presentation, and the original of the originals among the types of recording paper 3. The image forming apparatus according to claim 1, further comprising output recording sheet selecting means for selecting a type of recording sheet on which an image is to be formed based on the user input.

  According to this configuration, a plurality of sets of the types of recording paper and the correspondence relationships attached based on the density of the show-through image appearing on the type of recording paper are stored in association with each other. Whether or not each type of recording paper stored in association with each correspondence is suitable for forming the image on the basis of the density appearing in the document image and each stored correspondence. Is evaluated. Then, the evaluation result is presented to the user, the user input of the user corresponding to the presentation is acquired, and the type of the recording paper that forms the image of the document is selected based on the user input. Is done.

  Therefore, even when using various types of recording paper, the user can surely avoid show-through by inputting the user input according to the presented evaluation result and selecting the recording paper. .

  According to the present invention, even when various types of recording paper are used, a predetermined test image is formed on the recording paper, and a show-through image in which the test image appears on the back side of the recording paper is read. Then, based on the density of the corresponding portions of the test image and the show-through image, the density of the image formed on the recording paper and the density of the show-through generated on the back side of the recording paper are correlated with each other. The recording paper on which the original image is formed is determined based on the density appearing in the original image and the corresponding relationship, and the show-through is avoided with high accuracy. As a result, show-through can be reliably avoided even when various types of recording paper are used.

  Hereinafter, a copying machine 1 according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a copying machine 1. The copier 1 includes a document reading device 10, an image forming mechanism 20, a paper feed mechanism 30, a print control device 100, and an operation panel 40.

  The document reader 10 includes an automatic document feeder (ADF) and a scanner. The document reader 10 reads a document P set by a user and displays an image to be copied (hereinafter referred to as a document image). Input) to the print control apparatus 100.

  The image forming mechanism 20 includes various rollers for conveying recording paper, a photosensitive drum, a laser scanning unit, a transfer roller, a fixing roller, and the like, and performs image forming processing on the recording paper.

  The paper feed mechanism 30 includes paper feed cassettes 31 and 32 on which two types of recording papers R1 and R2 on which images are formed by the image forming mechanism 20 are loaded. The recording paper R1 loaded on the upper paper feed cassette 31 and the recording paper R2 loaded on the lower paper feed cassette 32 are of different types, and show-through occurs on the back side even if the same image is formed. Whether or not, and what sort of show-through occurs, is different.

  The operation panel 40 has various switches in addition to the liquid crystal touch panel 41 and provides a user interface to a user who operates the copying machine 1.

  The print control apparatus 100 is an information processing apparatus that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The document reading apparatus 10, the image forming mechanism 20, and the paper feeding mechanism 30. The operation panel 40 and other parts of the copying machine 1 are controlled.

  FIG. 2 is a block diagram of the copying machine 1.

  FIG. 2 shows functional blocks implemented in the print control apparatus 100. In the printing control apparatus 100, a show-through characteristic grasping unit 200, a recording paper data storage unit 300, and a document printing control unit 400 are realized.

  The document printing control unit 400 acquires a document image of the document P read by the document reading device 10 and inputs it to the image forming mechanism 20 to print on the recording paper R1 or the recording paper R2. At this time, the print control apparatus 100 controls the paper feed mechanism 30 to bring the recording paper into the image forming mechanism 20, but the paper feed mechanism 30 is not shown in FIG.

  The show-through characteristics grasping unit 200 performs processing for grasping the show-through characteristics of the recording papers R1 and R2 before the document image is printed in this way. The show-through characteristics will be described in detail later. The captured show-through characteristics of the recording papers R1 and R2 are stored in the recording paper data storage unit 300, and are referred to when the original print control unit 400 performs printing on the recording papers R1 and R2.

  The show-through characteristic grasping unit 200 includes a test image output unit 201, a back image acquisition unit 202, and a show-through characteristic specifying unit 203.

  The test image output unit 201 stores the test image 211f and controls the image forming mechanism 20 to print the test image 211f on the recording papers R1 and R2.

  FIG. 3 is a diagram illustrating the recording sheet 210P on which the test image 211f is printed. A test image 211f (left side) and a show-through image 211b in which the test image 211f appears on the back surface 210b of the recording paper 210P are shown together. Hereinafter, the recording paper 210P on which the test image 211f is printed is referred to as a show-through test paper 210P (see FIG. 2). Further, the show-through image 211b appearing on the show-through test paper 210P is hereinafter referred to as a back image 211b.

  By causing the test image output unit 201 to print such a test image 211f (test chart), the show-through characteristic grasping unit 200 grasps the show-through characteristic of the recording papers R1 and R2.

  FIG. 3 will be described in more detail later.

  Returning to FIG. 2, the show-through test paper 210 </ b> P on which the test image 211 f is printed is read by the document reading device 10, and the back image 211 b appearing on the back surface 210 b is input to the copying machine 1. The show-through test paper 210 </ b> P is set on the original reading device 10 by the user and read by the original reading device 10.

  The back image acquisition unit 202 acquires the back image 211 b from the document reading apparatus 10. The show-through characteristic specifying unit 203 acquires the back image 211b from the back image acquisition unit 202, acquires the test image 211f from the test image output unit 201, and analyzes both images, whereby the show-through test paper 210P ( The show-through characteristics of the recording paper R1 or the recording paper R2) are obtained.

  FIG. 4 is a diagram illustrating show-through characteristics. In this embodiment, the “show-through characteristic” is a limit density d described below. Hereinafter, the limit concentration d will be described with reference to FIGS.

  As shown in FIG. 3, the test image 211f (see FIG. 3) is divided into three areas corresponding to the three primary colors CYM (C: cyan, Y: yellow, M: magenta). In each region, portions having different concentrations 1 to 5 are formed. From density 1 to density 5, the formed image gradually becomes darker.

  In the back image 211b (right side in FIG. 3), the show-through of each color of CYM appears at different densities corresponding to these portions. In the case of FIG. 3, show-through occurs at the portions of the surface 210 f in the density 3 to 5, the density 2 to 5, and the density 3 to 5 in each region of CYM, and the darker the portion on the surface 210 f, that is, The larger the values 1 to 5 representing the density, the higher the density of the show-through.

  The graph shown in FIG. 4 shows the density 1 to 5 of the test image 211f formed on the front surface 210f of the test paper 210P (horizontal axis) and the density 1 to 2 on the back surface 210b for the cyan region (C). 5 shows the relationship between the density of the back image 211b appearing in each part of 5 and the (vertical axis).

  In this embodiment, the description is made so that printing is performed with three colors of CYM. Of course, printing may be performed with four colors of CYMK, and even if printing is performed with four or more colors, monochrome printing may be performed. Printing may be performed with.

  The data shown in the black circles in FIG. 4, that is, the density of the image displayed on the back surface 210 b when the density of the test image 211 f is 1 to 5 without excess or deficiency, is the test image 211 f acquired by the show-through characteristic specifying unit 203 and It can be specified by the back image 211b. Based on the density data of the back surface image 211b at such densities 1 to 5, the density of the back surface 210b at other densities is estimated as shown by the function indicated by the solid line in FIG. . In this estimation, for example, a least square method can be used.

  In such an estimated function, the maximum density of the surface 210f that can be printed on the test paper 210P without show-through is the limit density d described above. The show-through characteristic specifying unit 203 specifies the above-described function based on the acquired test image 211f and back-side image 211b, and shows the density of show-through for the first time as the front-side density (density shown on the x-axis side) increases. A location where (the density shown on the y-axis side) departs from 0 is obtained, and the density of the image formed on the surface side at that time (the density on the x-axis side) is defined as a limit density d. In this way, the show-through characteristic specifying unit 203 obtains the limit density d for each color of CMY. Note that such a limit density d represents the ease of show-through of the recording paper 210P.

  In the embodiment, it is assumed that the limit density d as described above is a show-through characteristic. However, the present invention is not limited to this, and the above-described limit density d of the above-described function is set in the positive x-axis direction. The copying machine 1 can also be configured so that the show-through characteristic also includes the inclination of the line exceeding the point (the part of the oblique line).

  The “correspondence relationship” described in the claims is a relationship between the densities specified by the show-through characteristics in this embodiment (when the surface density exceeds the limit density d, the density on the back surface becomes greater than 0). It corresponds to.

  Next, returning to FIG. 2, the recording paper data storage unit 300 includes a show-through characteristic storage unit 301, and the show-through characteristic obtained by the show-through characteristic specifying unit 203 is stored in the show-through characteristic storage unit 301. Is done.

  FIG. 5 is a diagram illustrating a data configuration of data configured in the show-through characteristic storage unit 301.

  The show-through characteristic storage unit 301 is a recording sheet that has been set in the paper cassettes 31 and 32 so far, such as “plain paper of company A”, “glossy paper of company A”, and “dedicated paper of company B”. Remember the type. The type of the recording paper is stored in the show-through characteristic storage unit 301 by inputting the paper with a predetermined barcode attached to each recording paper from the original reading device 10 to the copying machine 1. It may be stored, or may be stored when the user manually operates the operation panel 40 or the like.

  The show-through characteristic storage unit 301 (FIG. 2) stores the above-described show-through characteristics of the recording paper of that type in association with the data of such a recording paper.

  The show-through characteristic storage unit 301 is configured as a part of the recording paper data storage unit 300 (see FIG. 2), and the recording paper data storage unit 300 stores the types of recording paper stored in the show-through characteristic storage unit 301. In addition to the show-through characteristics of the recording paper of that type, it is stored which type of the recording paper is currently placed in the paper feed cassettes 31 and 32. The contents of the rightmost column shown in the figure correspond to the stored contents. In the case of FIG. 5, it is stored that “plain paper of company A” and “plain paper of company C” are placed in the paper feed cassettes 31 and 32, respectively.

  The show-through characteristic storage unit 301 obtains the show-through characteristic from the show-through characteristic specifying unit 203 and inquires of the test image output unit 201 about a paper feed cassette on which the recording paper on which the test image 211f is output is placed. The show-through characteristics storage unit 301 stores the acquired show-through characteristics in association with the type of recording paper placed in the paper feed cassette transmitted by this inquiry.

  Next, referring back to FIG. 2, the document print control unit 400 includes a recording sheet evaluation unit 401, a recording sheet automatic selection unit 403, and a recording sheet selection inquiry unit 402.

  The recording sheet evaluation unit 401 evaluates each recording sheet whose type is stored in the show-through characteristic storage unit 301.

  FIG. 6 is an explanatory diagram for explaining the evaluation of the recording paper performed by the recording paper evaluation unit 401. In FIG. 6, the horizontal axis indicates the density of the image formed on the recording paper (the density of the image appearing on the original image) in the horizontal direction. The black square indicates the maximum density of the image included in the document image. The limit concentration d has been described with reference to FIG.

  When the maximum density of the original image is larger than the limit density d of the recording paper, the recording paper shows through (see FIG. 4). Therefore, the minimum evaluation is performed on the recording paper (“× evaluation shown in the figure”). See “Range to do”).

  On the other hand, if the maximum density of the original image is smaller than the limit density d, no show-through occurs on the recording paper, but if the maximum density of the original image is much lower than the limit density d, the recording paper becomes meaningless and thick and expensive. Therefore, the limit density d should be as close as possible to the maximum density of the original image. Therefore, as long as the maximum density of the document image is smaller than the limit density d, the recording sheet evaluation unit 401 evaluates the recording sheet having the maximum density of the document image as close to the limit density d as possible.

  In FIG. 6, when the maximum density of the original is in the range of d to (dt) with respect to the limit density d of the recording paper, the best evaluation is performed, and the range of (dt) to (d-2t). If it is, the case where the evaluation is performed, such as the second, and the case where it is less than that, the third is shown. As described above, when the maximum density of the document image is larger than the limit density d, the lowest evaluation, that is, the fourth evaluation is performed.

  In this way, the recording paper evaluation unit 401 of this embodiment evaluates each recording paper in four stages.

  Returning to FIG. 2, the recording paper inquiry unit 402 creates a user interface on the liquid crystal touch panel 41 (see FIG. 1), and specifies the recording paper on which the obtained document image is to be formed by interacting with the user. .

  FIG. 7 is a diagram showing a user interface 402i that allows the user to select a recording sheet. The recording paper inquiry unit 402 displays such a user interface 402i on the liquid crystal touch panel 41 and interacts with the user.

  In this user interface 402i, the safety evaluation of show-through on each type of recording paper stored in the show-through characteristic storage unit 301 is performed using four symbols “「 ”,“ ◯ ”,“ Δ ”, and“ × ”. Indicated. This shows the result of the evaluation performed by the recording paper evaluation unit 401 described above (see FIG. 6). However, among the types of recording paper stored in the show-through characteristic storage unit 301, the recording paper R1 that is currently placed in the paper feed cassette 31 or the paper feed cassette 32 can be used immediately for image formation. , R2 only, only the display lines 31b and 32b corresponding to those recording sheets are enabled, and only the display lines 31b and 32b are touched to change the displayed recording sheets to the original. It can be selected as recording paper on which an image is to be formed.

  The recording paper inquiry unit 402 includes an evaluation display unit 402a and a user input unit 402b. The evaluation display unit 402a displays the above-described user interface 402i. The user input unit 402b obtains a recording paper selection result that the user has confirmed by touching the enter button 402s through the user interface 402i.

  Note that in the illustrated user interface 402i, the “dedicated paper for company B”, which was once placed in the paper feed cassette 31 or the paper feed cassette 31, rather than the recording paper placed in any of the paper feed cassettes 31 and 32, is shown in FIG. "Is higher in evaluation value. In such a case, the user can print on the B exclusive paper of the B company by replacing the recording paper placed in the paper supply cassette 31 or the paper supply cassette 32 as the exclusive paper of the B company. At this time, in the interface 402i displayed after the replacement, the display line 31b or the display line 32b displays “Exclusive paper of company B”, and the user prints an original image on the exclusive paper of company B by touching this. Can be made.

  If the user interface 402i cannot completely prevent show-through in any of the recording sheets in the paper feed cassettes 31 and 32, the user interface 402i proposes to the user to replace one of the recording sheets with a type of recording paper that can avoid show-through. May be. At this time, without suggesting until replacement, the recording paper with a relatively low level of show-through and relatively difficult to show through (relatively large limit density) is specified, and its use is It may be suggested. At this time, the recording paper inquiry unit 402 acquires not only a simple evaluation result but also the limit density value itself from the evaluation display unit 402a.

  Returning to FIG. 2, the recording paper automatic selection unit 403 suppresses activation of the above-described recording paper selection inquiry unit 402, and instead of the recording paper selection inquiry 402, the recording paper automatic selection unit 403 itself selects a recording paper on which a document image is to be formed. It has a function to determine (see FIG. 6). The recording paper automatic selection unit 403 has a predetermined flag. When the user sets a predetermined value to this flag from the operation panel 40 (FIG. 1), the recording paper automatic selection unit 403 performs the above-described suppression and selects the recording paper by itself. Do. The recording sheet automatic selection unit 403 always selects the recording sheet having the best evaluation value in the evaluation result performed by the recording sheet evaluation unit 401. If the evaluation values are the same between the recording sheets of the sheet feeding cassettes 31 and 32, any of them may be selected.

  FIG. 8 is a diagram showing a processing flow of the copying machine 1. When this process is performed, the show-through characteristics of the new recording paper are grasped by the show-through characteristics grasping unit 200, and printing on the recording paper is performed by the document print control unit 400 based on the grasped show-through characteristics. Is called.

  In step Sa1, the user starts the process of FIG. 8 using the liquid crystal touch panel 41 (FIG. 1). At this time, it is assumed that a new type of recording paper that does not store the show-through characteristics in the show-through characteristics storage unit 301 is already set in one of the paper feed cassettes 31 and 32. The user designates a paper feed cassette in which a new recording paper is set, and starts the processing of FIG.

  In step Sa2, a test image 211f is formed on the recording paper (show-through test paper 210P) of the designated paper feed cassette (see FIGS. 2 and 3).

  In step Sa3, the back image 211b of the show-through test paper 210P on which the test image 211f is formed is input to the show-through characteristic specifying unit 203 (see FIGS. 2 and 3).

  In step Sa4, the test image 211f in which the back image 211b is generated on the test paper 210P is acquired from the test image output unit 201 to the characteristic specifying unit 203 (see FIG. 2).

  In step Sa5, the characteristic specifying unit 203 specifies the show-through characteristic based on the input back image 211b and test image 211f (see FIGS. 2 to 4).

  In step Sa6, the specified show-through characteristics are stored in the show-through characteristics storage unit 301 in association with the type of recording paper of the show-through characteristics (see FIGS. 2 and 5).

  In step Sa7, an original image is acquired by the original print control unit 400 (see FIG. 2).

  In step Sa8, the show-through characteristic is read from the show-through characteristic storage unit 301 to the recording paper evaluation unit 401 (see FIG. 2).

  In step Sa9, the recording sheet evaluation unit 401 evaluates the recording sheet based on the read-through characteristics (see FIG. 6).

  In step Sa10, the recording paper automatic selection unit 403 detects whether a predetermined value is set in its own flag.

  If it is not set (step Sa10: NO), activation of the recording paper selection inquiry unit 402 is not suppressed, so that the processing of steps Sb1 and Sb2 is performed by the recording paper selection inquiry unit 402. In step Sb1, based on the result of the evaluation performed by the recording paper evaluation unit 401, a user interface 402i indicating information on the evaluation result to the user is displayed (see FIG. 7). In step Sb2, information on the recording paper selected by the user through the user interface 402i is acquired by the user input unit 402b.

  On the other hand, if it is set (step Sa10: YES), in step Sc1, the recording sheet automatic selection unit 403 selects a recording sheet on which image formation is to be performed.

  In step Sa11, the document print control unit 400 prints the document image on the recording sheet selected by the recording sheet automatic selection unit 403 or the recording sheet automatic selection unit 403 (see FIG. 2).

  As described above, the copying machine 1 is an image forming apparatus that reads an image of the original P and forms the read original image on the recording papers R1 and R2.

  In the copying machine 1, the test image 211f is formed on the recording paper (recording paper R1, R2), the back image 211b on which the test image 211f appears on the back surface 210b of the recording paper is read, and the test image 211f Based on the density of the corresponding portion with the back image 211b, the density of the image formed on the recording paper is associated with the density of the show-through caused by the image of the density on the back of the recording paper. The recording paper on which the document image is to be formed is determined on the basis of the density appearing in the document image and the correspondence relationship (the relationship between the density specified by the show-through characteristic) provided by the show-through characteristic specifying unit 203.

  Therefore, even if various types of recording paper are used, the test image 211f is formed on the recording paper, and the back image 211b on which the test image 211f appears on the back surface 210b of the recording paper is read and tested. Based on the density of the corresponding portions of the image 211f and the back image 211b, the density of the image formed on the recording paper is associated with the density of the show-through generated on the back of the recording paper by the image of the density (the show-through characteristics). Is identified). Then, based on the density appearing in the document image and the correspondence relationship (the relationship between the density specified by the show-through characteristics) added by the show-through characteristic specifying unit 203, the recording paper on which the document image is formed is determined, Show-through is avoided with high accuracy. As a result, show-through can be reliably avoided even when various types of recording paper are used.

  The show-through characteristic specifying unit 203 has a density (a density higher than the limit density d) of the density of the image formed on the recording paper, and the density of the show-through that causes the image of the density to occur on the back side of the recording paper ( (Density greater than 0).

  Further, the density of the image formed on the recording paper is associated with the presence or absence of show-through caused by the image having the density on the back surface of the recording paper.

  Therefore, when there is no show-through on the recording paper based on the density appearing on the document image and the correspondence relationship (the relationship between the density specified by the show-through characteristics) added by the show-through characteristic specifying unit 203, The recording paper can be determined as the recording paper on which the original image is formed.

  Further, the type of recording paper and the correspondence (the relationship between the density specified by the show-through characteristics) attached by the show-through characteristic specifying unit 203 based on the density of the back image 211b appearing on the type of recording paper. A plurality of sets are stored in association with each other. Then, based on the density appearing in the original image and the stored correspondences, it is determined that the most suitable image for forming the original image among the types of recording paper stored in association with the correspondences. One type of recording paper is selected, and that type of recording paper is determined as the recording paper on which the original image is to be formed.

  Therefore, it is possible to automatically select the most suitable recording paper for forming the original image.

  Further, the type of recording paper and the correspondence (the relationship between the density specified by the show-through characteristics) attached by the show-through characteristic specifying unit 203 based on the density of the back image 211b appearing on the type of recording paper. A plurality of sets are stored in association with each other. Then, based on the density appearing in the original image and each stored correspondence, it is evaluated whether or not each type of recording paper stored in association with each correspondence is suitable for forming the original image. The evaluation result is presented to the user, and the user input of the user corresponding to the presentation is acquired, and the type of recording paper on which the original image is formed is selected based on the user input. The

  Therefore, even when using various types of recording paper, the user can reliably avoid show-through by inputting user input according to the presented evaluation result and selecting the recording paper. .

  A show-through test paper 210P (see FIG. 2) output from the image forming mechanism 20 is provided to the original reading apparatus 10 so that the show-through test paper 210P is not troubled by the user. It may be set in the document reader 10.

  In addition, the image forming mechanism 20 may be provided with a separate scanner, and the output back image 211b of the show-through test paper 210P may be read simultaneously with the output of the test paper 210P.

  The test image 211 f formed on the show-through test paper 210 </ b> P may be read by the document reading apparatus 10 and used for specifying the show-through characteristics by the show-through characteristics specifying unit 203. In this way, the show-through characteristic can be specified with high accuracy.

  The test image output unit 201 (FIG. 2) may print the test image 211f on a recording sheet using the document print control unit 400.

  The automatic recording paper selection unit 403 has decided whether or not to select the recording paper by itself according to the value set in the predetermined flag. However, the recording paper may be selected by itself when relatively acceptable to the user.

1 is an explanatory diagram showing a copying machine 1. FIG. 1 is a block diagram of a copying machine 1. FIG. It is a figure which shows the recording paper 210P on which the test image 211f was printed. It is a figure which shows a show-through characteristic. 6 is a diagram illustrating a data configuration of data configured in a show-through characteristic storage unit 301. FIG. FIG. 6 is an explanatory diagram illustrating recording sheet evaluation performed by a recording sheet evaluation unit. It is a figure which shows the user interface 402i which makes a user select a recording paper. 3 is a diagram showing a flow of processing of the copying machine 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copier 10 Document reader 20 Image formation mechanism 30 Paper feed mechanism 31, 32 Paper feed cassette R1, R2 Recording paper 40 Operation panel 41 Liquid crystal touch panel 100 Print control apparatus 200 See-through characteristic grasping part 201 Test image output part 202 Back side image Acquisition unit 203 Back-through characteristic specifying unit 300 Recording paper data storage unit 301 Back-through characteristic storage unit 400 Document print control unit 401 Recording paper evaluation unit 402 Recording paper selection inquiry unit 402a Evaluation display unit 402b User input unit 403 Automatic recording paper selection Section 210P Back-through test paper 211f Test image 211b Back side image 210f Front side of back-through test paper 210P 210b Back side of back-through test paper 210P 402i User interface for allowing the user to select a recording paper 402s Determination buttons 31b and 32b Stacked on the copying machine 1 Display line of the recording sheet R1, R2 was

Claims (4)

An image forming apparatus that reads an image of a document and forms the read image on a recording sheet.
Test image forming means for forming a predetermined test image on recording paper;
A show-through image acquisition means for reading a show-through image on which the test image appears on the back side of the recording paper;
A correspondence specifying unit that associates the density of the image formed on the recording paper with the density of the show-through generated on the back surface of the recording paper based on the density of the corresponding portion of the test image and the show-through image;
An image forming apparatus comprising: a determining unit that determines a recording sheet on which an image of the original is to be formed based on a density appearing in the image of the original and a correspondence relationship added by the correspondence specifying unit.   2. The image forming apparatus according to claim 1, wherein the correspondence specifying unit associates the density of the image formed on the recording paper with the presence or absence of show-through caused by the image having the density on the back surface of the recording paper. A correspondence storage unit that stores a plurality of sets of associations of the types of recording paper and the correspondences attached by the correspondence specifying unit based on the density of the show-through image appearing on the type of recording paper;
The determination unit forms the image of the original most among the types of recording paper stored in association with each correspondence based on the density appearing in the image of the original and each correspondence stored. 3. An output recording sheet automatic determination unit that selects one type determined to be suitable for the recording and determines to form an image of the original on the recording sheet of the type. Image forming apparatus. A correspondence storage unit that stores a plurality of sets of associations of the types of recording paper and the correspondences attached by the correspondence identification unit based on the density of the show-through image appearing on the recording paper of the type;
The determining means includes
Based on the density appearing on the original image and each stored correspondence, it is evaluated whether each type of recording paper stored in association with each correspondence is suitable for forming the original image. Evaluation presentation means for presenting the evaluation result to the user,
An output recording paper selection unit that obtains a user input of the user in accordance with the presentation and selects a type of the recording paper on which the original image is to be formed among the types of recording paper based on the user input; The image forming apparatus according to claim 1, wherein:

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