JP2011128426A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite machine 100 capable of obtaining double-sided printed matter of high readability when a document whose both sides are printed with text is double-side printed. <P>SOLUTION: The composite machine 100 includes: a character arrangement determining means for determining whether the arrangement of characters in front surface image data matches with the arrangement of characters in rear surface image data when double-side printing is performed based on double-sided image data; a row-direction detecting means for detecting whether the row direction of the character row constituted by a plurality of characters in the image data is parallel or perpendicular to the longitudinal direction of the image data with respect to the front surface image data or the rear surface image data when the arrangement of the characters in the front surface image data matches with the arrangement of the characters in the rear surface image data; and a double-side printing controlling means for making an image forming means perform the double-side printing so that the conveying direction of paper to be double-side printed based on the double-sided image data become parallel to the row direction of the character row of the detected image data. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus capable of obtaining a double-sided printed material having excellent readability when performing double-sided printing on a document on which both sides are printed as a document.

  Image forming devices that record images on both sides of recording paper have emerged due to rationalization of office equipment and cost savings. The printed recording paper recorded on the front side is automatically turned over (reversed) and sent to the image recording unit. Conventionally, some image forming apparatuses including a double-sided printing (double-sided printing) mechanism that automatically performs continuous recording printing on the back side have been partially adopted.

  In double-sided printing, the recording paper can be reduced easily, but the readability of the printed material after double-sided printing is significantly degraded depending on the characteristics of the paper printed on both sides and the print density (image density) of the image data printed on both sides. There is a case. In other words, in an image forming apparatus having a conventional double-sided printing mechanism, when the user tries to print on both sides of the recording paper with a high image density setting, particularly when the recording paper is thin, There is a problem that the show-through (transparency) of the image of the seen back side print is remarkable, and it is necessary for the user to make double-sided printing again by thinly adjusting the image density setting.

  Further, when the user prints the OHT sheet, the second base paper, etc. without noticing the setting of the double-sided printing, the OHT sheet, the second base paper is almost transparent, and therefore the double-sided printing is performed on the OHP sheet, etc. The back print and the front print overlap and the show-through becomes significant. In this case as well, there is a problem that the user has to change the double-sided printing setting to the single-sided printing setting again. When the above-mentioned problem occurs, it takes time for the user and leads to a secondary problem that the recording paper and toner are wasted.

  As a technique for solving such a problem, Japanese Patent Application Laid-Open No. 07-209924 (Patent Document 1) discloses a paper feeding unit that feeds recording paper to a printing unit, and a developed image that is transferred to the recording paper and heated. The image forming means for fixing the recording paper to the recording paper, the double-sided printing paper feeding means for turning over the recording paper having the image fixed on one side and refeeding the image forming means, and the light emitted by the light emitting means are irradiated to the recording paper An image forming apparatus comprising: detecting means for detecting the recording paper transmittance of the irradiated light; and control means for controlling image formation based on the recording paper transmittance of the irradiated light detected by the detecting means Is disclosed. With this configuration, it is possible to control the density and fixing temperature suitable for each thickness of the recording paper by detecting the thickness and transparency of the recording paper, and as a result, the recording paper with a small thickness is fed. It is said that it will be possible to print optimally with little show-through.

Japanese Patent Laid-Open No. 07-209924

  However, the technique disclosed in Patent Document 1 requires a light emitting means for irradiating light to the recording paper and a sensor for detecting the transmittance of the recording paper based on the light irradiated to the recording paper, which increases the number of components. However, there is a problem that the cost performance is not excellent.

  In recent years, a booklet function that makes a plurality of printed materials a simple pamphlet and a bookbinding processing function that applies glue or the like to edges of the plurality of printed materials have been added to image forming apparatuses. When such a function is executed, it is usually executed in combination with the double-sided printing function, so that the quality of the printed material printed on both sides directly affects the quality of the booklet or bookbinding. Here, in the case where the show-through of the double-sided printed material is severe, there is a problem that the quality of the completed booklet or bookbinding becomes very poor when the double-sided printed material with severe set-off is booklet or bookbinding.

  This problem is particularly apparent in the current situation where on-demand printing is required for image forming apparatuses to print a small number of copies and a small lot of printed matter, and it is extremely possible to prevent show-through of printed matter printed on both sides as much as possible. It becomes important.

  Accordingly, the present invention has been made to solve the above-described problem, and provides an image forming apparatus capable of obtaining a two-sided printed material with excellent readability when a two-sided document is printed on both sides. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, an image forming apparatus according to the present invention is premised on an image forming apparatus including an image forming unit that performs double-side printing on a sheet based on double-sided image data of a document.

  In the image forming apparatus, when double-sided printing is performed based on double-sided image data, the character placement for determining whether or not the character placement in the front-side image data matches the character placement in the back-side image data A determination unit is provided. In addition, when the arrangement of characters in the front image data and the arrangement of characters in the back image data match, the image forming apparatus determines that the line direction of a character line composed of a plurality of characters in the image data A row direction detection unit is provided that detects whether the image data is parallel or perpendicular to the longitudinal direction of the image data with respect to either the front image data or the back image data. Further, the image forming apparatus applies the double-sided printing to the image forming unit so that the conveyance direction of the paper to be printed on both sides based on the double-sided image data is parallel to the line direction of the detected character line of the image data. Double-sided printing control means for printing is provided.

  The image forming apparatus further includes a paper feed cassette identification information for identifying the paper feed cassette and a paper orientation indicating whether the transport direction of the paper stored in the paper feed cassette is parallel or perpendicular to the longitudinal direction of the paper. A paper feed cassette selection storing means for storing information in association with each other is provided. Then, the double-sided printing control unit applies the double-sided printing to the image forming unit under the condition that the line direction of the detected character line of the image data matches the direction indicated by the paper orientation information of the paper feed cassette selection storage unit. By performing printing, it is possible to perform double-sided printing so that the paper conveyance direction is parallel to the line direction of the character line of the image data.

  Further, when the double-sided printing control means detects that the line direction of the character line is parallel to the longitudinal direction of the image data, the double-sided printing control means refers to the paper orientation information of the paper feed cassette selection storage means, Paper feed cassette identification information corresponding to paper orientation information indicating that the transport direction is parallel to the longitudinal direction of the paper is transmitted to the image forming means. The double-sided printing control means indicates that the paper transport direction is perpendicular to the longitudinal direction of the paper when it is detected that the line direction of the character line is perpendicular to the longitudinal direction of the image data. By transmitting the paper feed cassette identification information corresponding to the paper orientation information to the image forming unit, the image forming unit can be configured to perform duplex printing on the paper of the paper feed cassette corresponding to the paper feed cassette identification information.

  The image forming apparatus further includes a sheet presence detection sensor for detecting whether or not there is a sheet in the sheet feeding cassette for each sheet feeding cassette included in the image forming apparatus. When the duplex printing control unit transmits predetermined sheet cassette identification information to the image forming unit, the sheet cassette uses the sheet presence sensor of the sheet cassette corresponding to the sheet cassette identification information. The paper cassette identification information is transmitted to the image forming means when there is a sheet, and when there is no sheet, the sheet is detected with respect to the line direction of the character line of the double-sided image data. It is possible to display a screen that prompts the user to set the paper in the manual feed tray in a predetermined direction in which the transport direction is parallel, or a screen that prompts the user to replenish the paper in the paper feed cassette.

  According to the image forming apparatus of the present invention, when the arrangement of the character lines of the front image of the document matches the arrangement of the character lines of the back image, the conveyance of the paper is performed when performing duplex printing on a document including characters on both sides. When double-sided printing is performed so that the direction is parallel to the line direction of the character line of the double-sided image data, the character line arrangement position of the printed front image and the character line arrangement position of the back image are There is no significant variation in the direction perpendicular to the transport direction. Therefore, even if the arrangement of the character line of the front image and the arrangement of the character line of the back image overlap each other and show-through occurs in the double-sided printed material, for example, when the user reads the character line of the front image, The show-through of the character line of the image does not get in the way, and the text-line of the front image does not get in the way of the character line of the back image. As a result, it is not easy to see the contents of the printed material printed on both sides, and the readability of the printed material on both sides can be improved. In addition, in order to improve the readability of printed matter printed on both sides, it does not require a member for measuring the transmittance of paper, a control circuit for correcting the printing position of character lines, etc., which have been conventionally used. An image forming apparatus with excellent performance can be provided.

1 is a conceptual diagram illustrating an overall configuration inside a multifunction peripheral according to the present invention. It is a conceptual diagram which shows the whole structure of the operation part which concerns on this invention. It is a figure which shows the structure of the control system hardware of the multifunctional device which concerns on this invention. 1 is a functional block diagram of a multifunction peripheral according to an embodiment of the present invention. It is a flowchart for showing the execution procedure which concerns on embodiment of this invention. FIG. 6A is a diagram showing an example of a copy setting screen displayed on the touch panel according to the embodiment of the present invention, and a method for detecting the line direction of the character line by the line direction detecting unit according to the embodiment of the present invention. It is a figure (FIG. 6B) which shows an example for doing. FIG. 7A is a diagram illustrating an example of a paper feed cassette selection table according to the embodiment of the present invention (FIG. 7C), FIG. 7D is a diagram illustrating an example of a printed material according to an example, and FIG. 7D is a diagram illustrating an example of a printed material according to a comparative example. 7D2). FIG. 8A is a diagram illustrating an example of a paper set prompting screen displayed on the touch panel according to the embodiment of the present invention (FIG. 8E), and FIG. 8B is a diagram illustrating an example of a paper supply prompting screen (FIG. 8F).

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not. In addition, the alphabet “S” added in front of the numbers in the flowcharts means steps.

<Image forming apparatus>
Hereinafter, an image forming apparatus (for example, a multifunction peripheral) according to the present invention will be described.

  FIG. 1 is a conceptual diagram showing an overall internal configuration of a multifunction peripheral 100 according to the present invention. However, details of each part not directly related to the present invention are omitted.

  The multifunction peripheral 100 of the present invention corresponds to, for example, a printer, a single scanner, or a multifunction peripheral including a printer, a copy, a scanner, a fax machine, and the like. As an example, the operation of the multifunction device 100 when performing double-sided printing processing on the image of the document P using the multifunction device 100 will be briefly described.

  First, when a user performs a copy using the multifunction device 100, the document P is placed on the document table 101 provided on the upper surface of the multifunction device 100, and the copy function setting (double-sided printing, paper feed tray, etc.) is performed. ) Is input from the operation unit 102. Further, the user presses a start key provided on the operation unit 102 to cause the multifunction peripheral 100 to start duplex printing processing.

  When the duplex printing process is started, the multifunction peripheral 100 starts reading an image drawn on the surface of the document P. First, in the image reading unit 103, the light emitted from the light source 104 is reflected on the surface of the document P placed on the document table 101. The reflected light is guided to the image sensor 108 by the mirrors 105, 106, and 107. The guided light is photoelectrically converted by the image sensor 108 and read as surface image data when the image on the surface of the document P is printed on both sides.

  Further, when the user turns over the original P and presses the start key, the back side image of the original P is read as back side image data when double-sided printing is performed as described above. The read image data on the front surface and image data on the back surface are sent to the image forming unit 109 and transferred as a toner image.

  Note that the image reading unit 103 may be configured to read the images on both sides of the document P by the automatic document feeder 103a provided above the image reading unit 103. The automatic document feeder 103a is provided with, for example, a document conveyance path formed inside the platen cover, a pickup roller or a conveyance roller provided inside the platen cover, and the document conveyance path is connected to the document table 101. To the discharge tray via the reading position X where the image reading unit 103 reads. For example, a predetermined reading member that reads the image of the document P may be provided at a position facing the image reading unit 103 via the reading position X, and the images on both sides of the document P may be read in parallel. I do not care.

  The image forming unit 109 includes a photosensitive drum 110. The photosensitive drum 110 rotates in a predetermined direction at a constant speed, and the periphery thereof is charged in order from the upstream side in the rotation direction. A device 111, an exposure unit 112, a developing device 113, a transfer device 114, a cleaning unit 115, and the like are stacked.

  The charger 111 uniformly charges the surface of the photosensitive drum 110. The exposure unit 112 first irradiates the charged surface of the photosensitive drum 110 with a laser based on image data on the surface to form an electrostatic latent image. The developer 113 forms a toner image by attaching toner to the conveyed electrostatic latent image. The formed toner image is transferred to a recording medium (for example, a sheet such as paper) by the transfer device 114. The cleaning unit 115 removes excess toner left on the surface of the photosensitive drum 110. A series of these processes is executed by rotating the photosensitive drum 110.

  The sheets are fed from a plurality of paper feed cassettes 116 provided in the multi-function peripheral 100, for example, an upper cassette 116a, a middle cassette 116b, a lower left cassette 116c, and a lower right cassette 116d. Each contain sheets of different paper types. When the sheet is conveyed, the sheet is pulled out from any one of the sheet feeding cassettes 116a to 116d to the conveying path by the pickup roller 117. The paper feed cassettes 116 a to 116 d from which the sheet is drawn are determined based on the setting input to the operation unit 102 by the user.

  The sheet pulled out to the conveyance path is fed between the photosensitive drum 110 and the transfer device 114 by the conveyance roller 118 and the registration roller 119, and the toner image based on the image data on the surface is transferred by the transfer device 114. Then, it is conveyed to the fixing device 121.

  When the sheet to which the toner image has been transferred passes between a heating roller 122 and a pressure roller 123 provided in the fixing device 121, heat and pressure are applied to the toner image, and the toner image is fixed to the sheet. Then, the surface image of the document P is formed on the sheet. The heat amount of the heating roller 122 is optimally set according to the paper type, and the fixing is performed appropriately.

  The sheet on which the front image is formed is conveyed from the fixing device 121 to the closest branch point A. At the branch point A, a conveyance path B for conveying the sheet after image formation to the paper discharge tray 124 and a duplex printing conveyance path C for duplex printing are connected.

  Next, since the image forming process is performed based on the image data on the back side of the document P, the sheet on which the front surface image is formed is guided to the duplex printing conveyance path C, turned over, and further the photosensitive drum. It is conveyed to a transfer point D between 110 and the transfer device 114. By the time the sheet is conveyed to the transfer point D, a toner image is formed on the photosensitive drum 110 based on the back side image data. Therefore, when the sheet is conveyed to the transfer point D, the toner image of the image data on the back surface is appropriately transferred to the back surface of the sheet.

  When the toner image of the back side image data is transferred to the back side of the sheet, the transferred sheet is conveyed again to the fixing device 121 and fixed, and the back side image of the original P is formed on the sheet.

  The double-sided printed sheet is conveyed from the fixing device 121 to the branch point A, sent from the branch point A to the conveyance path B leading to the paper discharge tray 124, and stacked and stored in the paper discharge tray 124.

  The paper discharge tray 124 is provided on the side surface of the multi-function device 100, but a cylinder tray 125 is also provided in the body of the multi-function device 100, and the user inputs and sets the operation unit 102. In some cases, the double-sided printed sheets may be stacked on the in-body tray 125.

  In addition, the side surface of the multifunction peripheral 100 is provided with a manual feed tray 126 configured to convey the placed paper between the photosensitive drum 110 and the transfer unit 114, so that the user can When, for example, a plurality of sheets of paper are placed on the manual feed tray 126, a predetermined condition (for example, selected paper “manual feed tray”) is input, and the start key is pressed, transport in the vicinity of the manual feed tray 126 is performed. The roller 126 </ b> A rotates and the paper on the manual feed tray 126 is conveyed between the photosensitive drum 110 and the transfer device 114. As described above, even if the sheet is a sheet other than the sheet in the sheet feed tray, the multifunction peripheral 100 can transfer the toner image on the photosensitive drum 110 to the sheet.

  The above is the basic double-sided printing process in the multifunction peripheral 100. Note that the means for executing the image reading process from when the start key is pressed until the images on both sides (front and back sides) of the document P are read are the image reading unit 402, the image data on the front side of the document P, and the image data on the back side. A unit that forms a toner image based on the image and executes an image forming process until the corresponding toner image is transferred onto the front and back surfaces of the sheet is referred to as an image forming unit (described later). The image forming unit may perform the single-sided printing process by conveying the sheet to the conveyance path B without conveying the sheet to the conveyance path C.

  Next, the configuration of the operation unit 102 of the multifunction machine 100 will be described with reference to FIG. FIG. 2 is a conceptual diagram showing the overall configuration of the operation unit 102 according to the present invention.

  The user uses the operation unit 102 to input setting conditions related to the double-sided printing function as described above, for example, a document size, a sheet size (paper size), and the like, and confirm the input setting conditions. To do. When the setting condition is input, a touch panel 201, a touch pen 202, and an operation key 203 provided in the operation unit 102 are used.

  The touch panel 201 has both a function for inputting setting conditions and a function for displaying the setting conditions. That is, when a key in the setting screen displayed on the touch panel 201 is pressed (selected), a setting condition associated with the key is input to the multi-function device 100. Since the background color of the pressed key or the like is changed from white to gray in conjunction with the pressing, it is visually recognized whether the key or the like is being pressed by the background color of the key or the like.

  A touch pen 202 is provided in the vicinity of the touch panel 201. When the user touches the touch pen 202 with the tip of the touch pen 202, a sensor provided under the touch panel detects the touch destination. Since the tip of the touch pen is almost close to a point, the sensor detects, for example, the contact point in dot units (minimum unit). Therefore, compared with the case where the position in the touch panel 201 is designated with a finger, for example, the position designated with the touch pen 202 can be designated more accurately. The user can select a key or the like displayed on the touch panel 201 with the touch pen 202 instead of the fingertip.

  Further, a predetermined number of operation hard keys 203 are provided in the vicinity of the touch panel 201. For example, a ten key 204, a start key 205, a clear key 206, a stop key 207, a reset key 208, a power key 209, an up hard key 210, and a down key. A hard key 211 is provided.

  Next, the configuration of the control system hardware of the multifunction peripheral 100 will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of the control system hardware of the multifunction peripheral 100 according to the present invention. However, details of each part not directly related to the present invention are omitted.

  The control circuit of the MFP 100 includes a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, an HDD (Hard Disk Drive) 304, and a driver 305 corresponding to each driving unit. They are connected by a bus 306. The CPU 301 uses, for example, the RAM 303 as a work area, executes a program stored in the ROM 302, the HDD 304, and the like, and receives data and instructions from the driver 305 and an operation unit 103 (not shown) based on the execution result. The operation of each drive unit shown in FIG. 1 is controlled. In addition, each means (shown in FIG. 4) described later other than the drive unit is realized by the CPU 301 executing the program. The ROM 302, the HDD 304, and the like store programs and data for realizing each means described below.

<Embodiment of the present invention>
Next, referring to FIG. 4 and FIG. 5, the multi-function device 100 according to the embodiment of the present invention outputs a double-sided printed material with excellent readability when performing double-sided printing on a document on which both sides are printed as a document. explain. FIG. 4 is a functional block diagram of the multifunction peripheral 100 according to the embodiment of the present invention. FIG. 5 is a flowchart for illustrating an execution procedure according to the embodiment of the present invention.

  First, in order to perform double-sided printing on an A4 size original P that has been printed on both sides, the user places the original P in the vertical direction on the mounting tray of the automatic document feeder 103a. Here, placing the document P in the vertical direction on the placement tray means that the short side direction (direction perpendicular to the longitudinal direction) of the document P is matched with the transport direction (sub-scanning direction) of the document P. This means that the document P is placed on the placement tray.

  When the user turns on the multifunction device 100, the display receiving unit 401 displays a copy setting screen related to the copy function on the touch panel 201 (FIG. 6: S101).

  FIG. 6A is a diagram showing an example of a copy setting screen 600 displayed on the touch panel 201.

  In the copy setting screen 600, as shown in FIG. 6A, the message “Can copy” 601 prompting the user to execute the copy function, and the user selects paper, single-sided / double-sided setting, print density, and print magnification. Then, a setting item key 602 for receiving setting conditions regarding various functions corresponding to monochrome / color setting is displayed. When the copy setting screen 600 is displayed, the operation conditions related to various functions are initial conditions preset by a user (such as an administrator) (for example, paper selection “A4 portrait”, single-sided / double-sided setting “single-sided”). It is displayed with set.

  Here, when the user selects (presses) the “double-sided” key 602a of the single-sided / double-sided setting among the setting item keys 602, the display receiving unit 401 changes the background color of the “double-sided” key 602a from “white” to “ In addition to changing to “gray”, the background color of the “single-sided” key is changed from “gray” to “white”.

  Next, when the user confirms the setting conditions of paper selection “A4 portrait” and single-side / double-side setting “double-sided” and selects the start key 205, the display receiving unit 401 detects the selection of the start key 205, Image formation is started based on the setting conditions (FIG. 6: S102).

  Here, when the display receiving unit 401 refers to the single-sided / double-sided setting condition included in the received setting condition and determines that the single-sided / double-sided setting condition is “double-sided” (FIG. 6: S103 YES), first, Then, the image reading unit 402 is notified that the image data on both sides of the document P placed on the automatic document feeder 103a is read. Upon receiving the notification, the image reading unit 402 operates the automatic document feeder 103a to read the front image data corresponding to the front image of the document P and the back image data corresponding to the back image of the document P. The image reading unit 402 stores the read front image data and back image data in the image data storage unit 403 as a pair of double-sided image data.

  Next, the display receiving unit 401 notifies the character arrangement determining unit 404 that it is determined whether or not the character arrangement in the front surface image data matches the character arrangement in the back surface image data. Upon receiving the notification, when the double-sided image data is stored in the image data storage unit 403, the character arrangement determining unit 404 first includes characters in both the front-side image data and the back-side image data corresponding to the double-sided image data. It is determined whether it is document image data (FIG. 6: S104).

  The determination method may be any method, for example, the following method.

  That is, for example, assuming image data composed of pixels having density values in a range where black is “0” and white is “255”, the character arrangement determination unit 404 first constructs the surface image data. The pixel density value is compared with a predetermined threshold value corresponding to a color near black (for example, “5” corresponding to a gray color), and a pixel having a density value less than the threshold value is compared with that near black or black Extracted as black pixels corresponding to the color. Next, the character arrangement determination unit 404 determines whether or not the plurality of extracted black pixels are adjacent (continuous) to each other, so that a pixel region (a black pixel region) composed of the plurality of black pixels is determined. ). Then, the character arrangement determining unit 404 determines whether the extracted black pixel region is within a size corresponding to a predetermined character size, for example, or has a shape that is the same as or similar to the shape of the predetermined character. It is determined whether or not the black pixel region is a character. If the black pixel area is a character, the front image data includes a character, and the character arrangement determination unit 404 determines whether the back surface image data also includes a character by a similar method. judge.

  This determination may be made for a predetermined number of black pixel areas, a black pixel area in the predetermined area, or a black pixel area in the entire area of the surface image data.

  As a result of the determination, if the front image data does not include characters, or the front image data includes characters but the back image data does not include characters (FIG. 6: S104 NO), this Even if double-sided printing is executed based on such double-sided image data, the problem of show-through does not occur. Therefore, the character arrangement determination unit 404 executes double-sided printing based on the front-side image data and the back-side image data. Then, the image forming unit 405 is notified. In this case, the image forming unit 405 receives the setting condition from the display receiving unit 401 and executes double-sided printing based on the double-sided image data (FIG. 6: S105).

  On the other hand, as a result of the determination, if characters are included in both the front image data and the back image data (FIG. 6: S104 YES), then the character arrangement determining means 404 determines the character arrangement in the front image data. Then, it is determined whether or not the arrangement of characters in the back surface image data matches (FIG. 6: S106).

  The determination method may be any method, for example, the following method.

  That is, the character arrangement determining unit 404 has a plurality of characters (for example, nine characters) included in a predetermined region in the surface image data (for example, a square region having a side of 2 cm with the center position of the surface image data as the center). ) Is calculated for each character, and similarly, the center positions of a plurality of characters (for example, nine characters) included in the area in the back surface image data corresponding to the area are calculated. To do. Next, the character arrangement determining unit 404 compares the center positions of the plurality of characters in the calculated front surface image data and the center positions of the plurality of characters in the back surface image data for each character, and the number of characters that match both of them. Is calculated, and a ratio (hereinafter referred to as a determination ratio) obtained by dividing the number of characters (9 characters) included in the predetermined area with respect to the counted number of characters is calculated, and the determination ratio is a predetermined ratio (for example, , 70%) is determined. If the determination ratio exceeds the predetermined ratio, the character arrangement determination unit 404 determines that the arrangement of characters in the front image data matches the arrangement of characters in the back image data (FIG. 6: S106 YES). ).

  On the other hand, as a result of the determination, if the determination ratio is less than the predetermined ratio (FIG. 6: S106 NO), the problem of show-through does not occur even when double-sided printing is executed based on such double-sided image data. The determination unit 404 notifies the image forming unit 405 to execute double-sided printing based on the front surface image data and the backside image data, and the image forming unit 405 performs double-sided printing based on the double-sided image data. This is executed (FIG. 6: S105).

  When the character arrangement determining unit 404 determines that the character arrangement in the front image data matches the character arrangement in the back image data (FIG. 6: S106 YES), the determination result is used as the row direction detecting unit. 406 is notified. Upon receiving the notification, the line direction detection means 406 determines whether the line direction of the character line composed of a plurality of characters in the image data is parallel or perpendicular to the longitudinal direction of the image data, the surface image data or the Detection is performed for any of the back surface image data (FIG. 6: S107).

  The detection method may be any method, for example, the following method.

  FIG. 6B is a diagram illustrating an example for explaining a method in which the line direction detection unit 406 detects the line direction of a character line.

  That is, the row direction detection unit 406 selects surface image data from the double-sided image data, and the length of the vertical side 603 (corresponding to the length in the scanning direction) and the length of the horizontal side 604 are selected from the selected surface image data. The long side is specified by comparing the length (corresponding to the length in the sub-scanning direction), and the axial direction of the long side is determined as the longitudinal direction of the surface image data. Next, the row direction detection unit 406 includes a plurality of characters (for example, a square area 605 having a side of 2 cm with the center position of the surface image data as a center in FIG. 6B) in the surface image data. In FIG. 6B, nine characters) are selected, and one character (“E” 606 in FIG. 6B) located at the center is identified from among the selected characters. The row direction detection unit 406 then selects one character (referred to as a longitudinal character) adjacent to the determined character “E” 606 (referred to as a specified character) adjacent in the longitudinal direction. Here, when there are two longitudinal characters for the specific character “E” 606 (“D” 607 and “F” 608 in FIG. 6B), the row direction detecting means 406 is preset by the user. One longitudinal character (“D” 607 in FIG. 6B) in the direction (upward in FIG. 6B) is selected. Then, the row direction detection unit 406 calculates a distance LD (referred to as a longitudinal direction distance) between the specific character “E” 606 and the longitudinal direction character “D” 607. Here, the method for calculating the distance between characters is, for example, as shown in FIG. 6B, between a minimum frame 609 surrounding the specific character “E” 606 and a minimum frame 610 surrounding the longitudinal direction character “D” 607. A method of calculating the distance LD is adopted, but as another method, a method of calculating a distance between the center position of the specific character and the center position of the longitudinal character may be used.

  Next, the row direction detection means 406 detects a character (E in FIG. 6B) that is adjacent to the specific character “E” 606 in the short direction perpendicular to the longitudinal direction. , Hereinafter referred to as a short direction character), and a distance SD (referred to as a short direction distance) between the selected short direction character “H” 611 and the specific character “E” 606 is calculated. . The line direction detection unit 406 compares the calculated longitudinal direction distance LD and the short direction distance SD, and when the longitudinal direction distance LD is short, the line direction of the character line is parallel to the longitudinal direction. When the short direction distance SD is short, it is detected that the line direction of the character line is perpendicular to the longitudinal direction.

  In addition, when it is detected whether the line direction of the character line for the front image data is parallel or perpendicular to the longitudinal direction of the image data, the character arrangement in the front image data and the character arrangement in the back image data are already Therefore, the line direction of the character line in the front image data and the line direction of the character line in the back image data are naturally matched (parallel). It is not necessary to detect the line direction of the character line in the image data.

  When the line direction detection unit 406 detects whether the line direction of the character line is parallel or perpendicular to the longitudinal direction of the surface image data in the surface image data (FIG. 6: S107), the detection result is sent to the duplex printing control unit 407. Send. Receiving the detection result, the double-sided printing control unit 407 is configured so that the conveyance direction of the paper to be printed on both sides based on the double-sided image data is parallel to the line direction of the detected character line of the image data. The image forming unit 405 prints on both sides.

  Any method may be used for double-sided printing so that the conveyance direction of the paper on which double-sided printing is performed based on the double-sided image data is parallel to the line direction of the detected character line of the image data. For example, the following method is used.

  That is, the double-sided printing control unit 407 detects, as the detection result, detection result information indicating whether the line direction of the character line of the surface image data is parallel or perpendicular to the longitudinal direction of the surface image data (for example, the character line of the image data). , The sheet feeding cassette stored in the sheet feeding cassette selection storage means 408 is received ("1" indicating that the row direction is parallel to the longitudinal direction of the image data, and "0" indicating that it is vertical). Refer to the selection table.

  FIG. 7C is a diagram illustrating an example of the paper feed cassette selection table 700.

  As shown in FIG. 7C, the paper feed cassette selection table 700 includes paper feed cassette identification information 701 for identifying a paper feed cassette (for example, “A01”) and the size of the paper stored in the paper feed cassette. Information 702 (referred to as paper size) is associated with information 703 (referred to as paper orientation information) indicating whether the transport direction of the paper stored in the paper feed cassette is parallel or perpendicular to the longitudinal direction of the paper. It is remembered. As the paper orientation information 703, for example, “1” indicating that the paper transport direction is parallel to the longitudinal direction of the paper and “0” indicating vertical are employed. The “1” corresponds to the paper orientation “horizontal” in the paper selection of the setting item, and the “0” corresponds to the paper orientation “vertical” in the paper selection of the setting item. For reference, if paper selection of setting items corresponding to the paper cassette identification information 701, the paper size 702, and the paper orientation information 703 is added to the paper cassette selection table 700 shown in FIG. For example, the identification information “A01” corresponds to the paper selection “A4 landscape”, and “A02” corresponds to “A3 landscape”.

  The double-sided printing control unit 407 referring to the paper cassette selection table 700 compares the received detection result information (for example, “1”) with the paper orientation information 703 (“1” or “0”), and both Are matched, the paper feed cassette identification information 701 and the paper size 702 corresponding to the matching paper orientation information 703 ("A01", "A4", "A02", "A3" in FIG. 7C) are supplied. Obtained from the paper cassette selection table 700 (FIG. 6: S108).

  Here, since the longitudinal direction of the paper corresponds to the longitudinal direction of the double-sided image data, the detection result information and the paper orientation information 703 coincide with each other, in other words, the transport direction of the paper is relative to the longitudinal direction of the paper. The fact that the line direction of the character lines of the double-sided image data is parallel to the longitudinal direction of the image data means that the paper transport direction is parallel to the line direction of the character lines of the double-sided image data. It means that there is. Therefore, if a sheet is fed from a sheet cassette corresponding to the acquired sheet cassette identification information 701 and duplex printing is performed on the sheet based on the duplex image data, the line direction of the character line of the duplex image data is determined. Therefore, double-sided printing is performed so that the paper transport direction is parallel to the paper.

  The double-sided printing control unit 407 that has acquired the sheet cassette identification information 701 and the sheet size 702 in which the detection result information and the sheet orientation information 703 coincide with each other is selected from the display accepting unit 401 as a sheet selection “A4 portrait”. In other words, the paper cassette identification information “A03” (input paper cassette identification information) and the paper size “A4” (input paper size) input by the user are acquired. Then, the duplex printing control unit 407 inputs the input paper size “A4” corresponding to the acquired input paper feed cassette identification information “A03” and the paper sizes 702 (“A4”, “A3” acquired from the paper feed cassette selection table 700. ”) And the paper cassette associated with the paper feed identification information“ A01 ”that matches the two is determined as the paper feed cassette that feeds paper when the image forming unit 405 performs duplex printing (FIG. 6). : S109).

  When the paper feed cassette identification information 701 is determined, the duplex printing control unit 407 transmits the determined paper feed cassette identification information 701 to the image forming unit 405. The image forming unit 405 that has received the paper feed cassette identification information 701 feeds the paper from the paper feed cassette corresponding to the paper feed cassette identification information 701, and performs duplex printing on the paper on both sides corresponding to the double-sided image data. (FIG. 6: S105). Specifically, the image forming unit 405 feeds paper from the paper feed cassette having the paper feed identification information “A01” (setting item paper selection “A4 landscape”), and prints the double-sided image data corresponding to the double-sided image data on the paper. Print images on both sides. As described above, the duplex printing control unit 407 changes the sheet selection setting condition “A4 portrait” received from the user to the specific setting condition “A4 landscape”, so that the image forming unit 405 determines the sheet conveyance direction. Double-sided printing is executed so as to be parallel to the line direction of the character line of the double-sided image data.

  Note that the following procedure is used for single-sided printing of the original P. That is, when the display receiving unit 401 that detects selection of the start key 305 determines that the single-sided / double-sided setting is “single-sided” in the received setting condition (FIG. 6: S103 NO), a problem of show-through due to double-sided printing occurs. Therefore, the image reading unit 402 is caused to read image data on one side of the document P, and the image forming unit 405 is caused to form an image on a sheet based on the image data on one side (FIG. 6: S110). This is a normal single-sided printing process.

<Operations and effects of the present invention, examples and comparative examples>
Here, the operation and effect of the multifunction peripheral according to the embodiment of the present invention will be described.

  First, as an example, a case will be described in which double-sided printing is performed so that the conveyance direction of a sheet on which double-sided printing is performed based on double-sided image data is parallel to the line direction of a character line of double-sided image data. The description will be made on the assumption that the size, number and arrangement of the character lines of the front image of the document P are the same as the size, number and arrangement of the character lines of the back image.

  FIG. 7D1 is a diagram illustrating an example of the printed material according to the embodiment. Note that the type, size, and the like of the characters constituting the character line are omitted because they are almost unrelated to the gist of the invention. In addition, the character lines of the printed front image are indicated by solid lines, and the character lines of the printed back image are indicated by broken lines.

  As shown in FIG. 7D1, the arrangement of the character lines of the printed front image and the arrangement of the character lines of the back image almost overlap, and the deviation between the arrangement positions of the two is perpendicular to the paper transport direction (short paper). It was about 0.1 mm with respect to (hand direction). As described above, when double-sided printing is performed so that the paper conveyance direction is parallel to the line direction of the character lines of the double-sided image data, the arrangement of the character lines of the front image and the character line of the back side image is changed. For example, when the user reads the character line of the front image, the show-through of the character line of the back image does not get in the way, and the character line of the front image is not disturbed. The show-through does not get in the way, and the readability of the printed matter printed on both sides can be improved.

  Next, as a comparative example, a case will be described in which double-sided printing is performed such that the conveyance direction of a sheet on which double-sided printing is performed based on double-sided image data is perpendicular to the line direction of the character line of double-sided image data.

  FIG. 7D2 is a diagram illustrating an example of a printed material according to a comparative example.

  As shown in FIG. 7D2, the arrangement of the character lines of the printed front image and the arrangement of the character lines of the back image hardly overlap, and the character lines of the front image and the character lines of the back image are close (adjacent). However, the displacement of the arrangement position of both was about 5 mm with respect to the short side direction of the paper (paper conveyance direction). In this way, when double-sided printing is performed so that the paper conveyance direction is perpendicular to the line direction of the character lines of the double-sided image data, the character lines of the front image and the character lines of the reverse side characters are close to each other. For example, when the user reads a character line of the front image, the character line of the back image adjacent to the character line of the front image is seen through (emits), and the character line of the front image is displayed. Can easily confuse the character line of the back image and the character line of the front image. Therefore, it is understood that it becomes difficult to read the character line of the surface image, and the readability of the printed matter printed on both sides is deteriorated.

  In the operation and effect of the present invention, the size, number, and arrangement (document format) of the character line of the front image of the original P are the same as the size, number, and arrangement (document format) of the character line of the back image. However, since the document format of the front image and the document image of the back image of the original P printed on both sides are almost the same or similar, the document formats of the two are slightly different. However, the double-sided printed matter within the range in which the character arrangement determining unit 404 determines that the arrangement of the two characters coincides has the above-described effects.

  By the way, when the arrangement of characters in the front image data and the arrangement of characters in the back image data match, the paper conveyance direction is parallel or perpendicular to the line direction of the character lines of the double-side image data. The reason why the arrangement of the character lines of the front image to be printed and the arrangement of the character lines of the back image varies depending on whether or not it is performed.

  That is, when transporting the paper stored in the paper feed cassette, the paper that contacts the pickup roller receives the rotational force (frictional force) of the pickup roller by rotating the pickup roller provided in the paper feed cassette. Then, the movement in the rotation direction is started and conveyed to the image forming unit 109. Here, the conveyance speed of the conveyed paper varies slightly depending on the strength of the frictional force received from the pickup roller, that is, the degree of contact of the pickup roller received by the paper. When the sheet conveyance speed slightly varies, the timing at which the sheet conveyed from the sheet feeding cassette reaches the image forming unit 109 varies. On the other hand, the image forming unit 109 forms a toner image (or an electrostatic latent image) on the photosensitive drum 110 to form an image on the paper based on the timing of the paper reaching the image forming unit 109 calculated in advance. Therefore, the arrangement position of the character line of the image printed on the paper is parallel to the conveyance direction of the paper according to the change in the timing when compared with the arrangement position of the character line of the image data read from the document P. Will vary slightly. When performing double-sided printing, for example, if the arrangement position of the character lines of the front image formed based on the front image data fluctuates in parallel with the paper transport direction, the back surface on which image formation is performed based on the subsequent back image data It also affects the position of the text line in the image. As a result, even when the character arrangement in the front image data and the character arrangement in the back image data match, the character line arrangement position of the printed front image and the character line arrangement of the back image The position fluctuates in parallel with the sheet conveyance direction.

  On the other hand, the direction perpendicular to the sheet conveyance direction is hardly affected by the timing variation caused by the sheet conveyance described above. Therefore, for example, as described above, when the arrangement of characters in the front surface image data and the arrangement of characters in the back surface image data match, even if the surface image to be printed may be affected by disturbance, The arrangement position of the character line and the arrangement position of the character line of the back image almost coincide with the direction perpendicular to the sheet conveyance direction. As a result, it is possible to obtain the above-described functions and effects of the present invention.

  As described above, in the MFP according to the present invention, when double-sided printing is performed based on double-sided image data, whether or not the character arrangement in the front surface image data matches the character arrangement in the backside image data. When the character arrangement determining means 404 for determining the character arrangement in the front image data matches the character arrangement in the back image data, the line direction of the character line composed of a plurality of characters in the image data A line direction detecting means 406 for detecting whether the image data is parallel or perpendicular to the longitudinal direction of the image data with respect to either the front surface image data or the back surface image data, and the line of the character line of the detected image data A double-sided printing control unit 407 for causing the image forming unit 405 to perform double-sided printing so that the conveyance direction of the paper on which double-sided printing is performed based on the double-sided image data is parallel to the direction.

  With this configuration, when the arrangement of the character lines on the front image of the document matches the arrangement of the character lines on the back image, when carrying out duplex printing on a document including characters on both sides, the paper transport direction is When double-sided printing is performed so as to be parallel to the line direction of the character line, the character line arrangement position of the printed front image and the character line arrangement position of the back image are perpendicular to the paper transport direction. Does not fluctuate greatly. Therefore, even if the arrangement of the character line of the front image and the arrangement of the character line of the back image overlap each other and show-through occurs in the double-sided printed material, for example, when the user reads the character line of the front image, The show-through of the character line of the image does not get in the way, and the text-line of the front image does not get in the way of the character line of the back image. As a result, it is not easy to see the contents of the printed material printed on both sides, and the readability of the printed material on both sides can be improved. In addition, in order to improve the readability of printed matter printed on both sides, it does not require a member for measuring the transmittance of paper, a control circuit for correcting the printing position of character lines, etc., which have been conventionally used. It is possible to provide a multifunction device with excellent performance.

  Note that the duplex printing control unit 407 according to the embodiment of the present invention is configured to transmit the determined sheet cassette identification information 701 as it is to the image forming unit 405, but other configurations may be added. . For example, when the duplex printing control unit 407 determines specific sheet cassette identification information 701, it detects whether or not there is a sheet in the sheet cassette corresponding to the sheet cassette identification information 701. The detection method includes, for example, an on / off signal of a sheet presence detection sensor that detects the presence or absence of a sheet by detecting light reflected from a stored sheet provided in advance in each sheet feeding cassette. The double-sided printing control means 407 may acquire and detect the presence of paper. At this time, the double-sided printing control unit 407 executes the above-described detection process on the paper presence detection sensor of the paper feed cassette corresponding to the determined paper feed cassette identification information 701.

  If the sheet is present as a result of the detection, the duplex printing control unit 407 transmits the paper feed cassette identification information 701 to the image forming unit 405. If the sheet is not present, the duplex printing control unit 407 displays the display. The unit 401 causes the touch panel 201 to display a paper setting prompt screen for displaying that the paper is set in a predetermined direction on the manual feed tray.

  FIG. 8E is a diagram showing an example of a paper set prompting screen 800 displayed on the touch panel 201.

  As shown in FIG. 8E, the paper setting prompt screen 800 indicates a message “start double-sided printing” 801 to notify the user that double-sided printing is performed, and the line direction of the character line of the double-sided image data. A message stating that “the character line direction of the double-sided image data is vertical” 802 and a message stating the paper orientation of the paper cassette “paper orientation of the paper cassette is vertical” 803 , A message that informs the user that paper can be prevented from being placed sideways in the manual feed tray. ”804, a“ feed from manual feed tray ”key 805 for executing double-sided printing on the paper set in the manual feed tray, and the manual feed tray. And "as double-sided printing" key 806 is displayed for executing double-sided printing on the paper sheet cassette setting condition rather than paper.

  While viewing the paper setting prompt screen 800, for example, the user sets the paper sideways on the manual feed tray 126 (the direction in which the paper transport direction coincides with the longitudinal direction of the paper) and feeds the paper from the manual feed tray. When the “” key 805 is selected, the duplex printing control unit 407 transmits sheet cassette identification information corresponding to the manual feed tray 126 to the image forming unit 405. Then, the image forming unit 405 that has received the paper feed cassette identification information operates the conveyance roller 126A provided in the manual feed tray 126 to execute double-sided printing on the paper in the manual feed tray 126. Thus, double-sided printing is executed such that the paper conveyance direction is parallel to the line direction of the character lines of the double-sided image data, and it is possible to prevent the double-sided printed material from being set off.

  On the other hand, if the user who thought that the show-through may be intense selects the “double-sided printing” key 806 without placing paper on the manual feed tray 126, the double-sided printing control means 407 is determined. The image forming unit 405 is notified that double-sided printing is to be performed without transmitting the sheet feeding cassette identification information (sheet feeding identification information of the sheet cassette without paper) to the image forming unit 405. Receiving the notification, the image forming unit 405 executes double-sided printing on the paper in the paper feed cassette designated by the setting condition received from the user or the initial condition.

  With this configuration, even when there is no paper in a specific paper feed cassette, the duplex printing control unit 407 causes the user to place the paper on the manual feed tray in a predetermined orientation using the paper setting prompt screen. It is possible to prevent the intensity of show-through.

  If there is no paper in the paper cassette corresponding to the predetermined paper cassette identification information, the duplex printing control unit 407 displays the paper in the paper cassette in the display accepting unit 401 instead of the paper set prompting screen 800. A screen for prompting the replenishment of paper to indicate that the replenishment is to be supplied may be displayed on the touch panel 201.

  FIG. 8F is a diagram illustrating an example of a paper supply prompt screen 807 displayed on the touch panel 201.

  On the paper supply prompting screen 807, as shown in FIG. 8F, a message 801 notifying the user that double-sided printing is performed, a message 802 indicating the line direction of the character line of the double-sided image data, and a paper feed cassette Message 803 indicating the orientation of the paper, and preventing the show-through if the user supplies the paper to a predetermined paper cassette (for example, “A4 landscape”) and prints on both sides of the paper in the paper cassette. There is no paper in the paper cassette corresponding to the message “A4 landscape” to inform you that it is possible. By using double-sided printing with the paper cassette, you can prevent show-through. 808, “A4 landscape, duplex printing” key 809 for executing double-sided printing on paper in a predetermined paper cassette, and double-sided printing on paper in a specified paper cassette without replenishing paper A “double-sided printing” key 810 for execution is displayed.

  For example, when the user replenishes the paper into the “A4 landscape” paper feed cassette and selects the “A4 landscape” duplex printing key 809 while viewing the paper replenishment prompt screen 807, duplex printing control is performed. The unit 407 transmits the paper feed cassette identification information corresponding to “A4 landscape” to the image forming unit 405. Then, the image forming unit 405 that has received the paper cassette identification information executes duplex printing on the paper in the paper cassette corresponding to “A4 landscape”. Thus, double-sided printing is executed such that the paper conveyance direction is parallel to the line direction of the character lines of the double-sided image data, and it is possible to prevent the double-sided printed material from being set off.

  On the other hand, if the user who thought that the show-through may be intense selects the “double-sided printing” key 810, the double-sided printing control means 407 determines the paper feed cassette identification information (paper that does not exist). The image forming unit 405 is notified that double-sided printing is to be performed without transmitting the cassette paper feed identification information) to the image forming unit 405. Receiving the notification, the image forming unit 405 executes double-sided printing on the paper in the paper feed cassette designated by the setting condition received from the user or the initial condition.

  Even in this configuration, the double-sided printing control means 407 can prompt the user to replenish paper in a predetermined paper feed cassette using the paper replenishment prompting screen, thereby preventing the show-through intensity.

  In addition, the character arrangement determining unit 404 according to the embodiment of the present invention calculates the center position of a plurality of characters included in a predetermined area in the front surface image data for each character, and also includes in the back surface image data corresponding to the area. The center position of a plurality of characters included in the area is calculated for each character, and the center position of the character in the front surface image data and the center position of the character in the back surface image data are compared for each character. The number of characters to be counted was counted. Here, it is not necessary that the two match completely. For example, if the distance between the center position of the character of the front surface image data and the center position of the character of the back surface image data is within a predetermined threshold, It may be determined that they match.

  In addition, the character arrangement determining unit 404 according to the embodiment of the present invention is configured so that the character in the front surface image data is based on the number of characters in which the center position of the character in the front surface image data matches the center position of the character in the back surface image data. It is determined whether or not the arrangement of the characters and the arrangement of characters in the back surface image data match, but other configurations may be used. For example, the character arrangement determination unit 404 connects the plurality of characters included in the front surface image data and the back surface image data to each other, or performs image deterioration processing such as binarization processing. The character arrangement pattern of each of the back surface image data is generated, and by determining whether the character arrangement pattern of the generated front surface image data matches the character arrangement pattern of the back surface image data, the character arrangement of both It may be configured to determine whether or not.

  The line direction detection unit 406 according to the embodiment of the present invention detects whether the line direction of a character line composed of a plurality of characters in the image data is parallel or perpendicular to the longitudinal direction of the image data. In addition, the longitudinal direction distance LD and the lateral direction distance SD described above are compared, and when the longitudinal direction distance LD is short, it is detected that the line direction of the character line is parallel to the longitudinal direction, and the lateral direction When the distance SD is short, it is configured to detect that the line direction of the character line is perpendicular to the longitudinal direction, but other configurations may be used. For example, a table associating information indicating the line direction (whether parallel or vertical) with a predetermined number of character arrangement patterns in which a predetermined number of character lines are arranged in the line direction is prepared in advance. The detection unit 406 obtains the character arrangement pattern of the image data by performing processing for connecting the character of the shortest distance to the characters of the front surface image data or the back surface image data, or performing the image degradation processing or the like. Information indicating the line direction of the collated character arrangement pattern is obtained by collating the character arrangement pattern with the character arrangement pattern in the table, and the line direction of the character line is parallel to the longitudinal direction of the image data. Alternatively, it may be configured to detect whether it is vertical or vertical. Further, the line direction detection means 406 extracts a region other than the characters of the front surface image data or the back surface image data, that is, a continuous shape of the white pixel region, and detects the axial direction of the shape as the line direction of the character line. Thus, it may be configured to detect whether the line direction of the character line is parallel or perpendicular to the longitudinal direction of the image data.

  In addition, a method for determining whether or not the character arrangement in the front image data and the character arrangement in the back image data match, and whether the line direction of the character line is parallel or perpendicular to the longitudinal direction of the image data. Are detected by character characteristics of image data, for example, character size, distance between characters, linearity of a character string determined from a plurality of characters, character shape, and character arrangement pattern composed of a plurality of characters. The shape may be based on the shape of the region other than the character, its linearity, the shape of the white region, its linearity, its pattern, and the like.

  In addition, the duplex printing control unit 407 according to the embodiment of the present invention is configured so that the conveyance direction of the sheet printed on both sides based on the duplex image data is parallel to the line direction of the detected character line of the image data. In addition, the image forming unit 405 is made to perform double-sided printing by changing the paper selection setting conditions, but other methods may be used. For example, the paper transport direction is determined based on the paper selection setting condition (for example, “A4 landscape”) input by the user and the paper orientation information in the paper cassette selection table, and the determined paper transport is performed. The double-sided image data is rotated so that the line direction of the character line of the double-sided image data detected by the line direction detecting unit is parallel to the direction, and is re-stored (reset) in the image data storage unit. You may comprise. Specifically, if the setting condition for paper selection is “A4 landscape”, the transport direction of the paper stored in the paper cassette related to “A4 landscape” is based on the paper orientation information “1”. Parallel to the longitudinal direction. On the other hand, when the line direction of the character line of the double-sided image data stored in the image data storage unit is perpendicular to the longitudinal direction of the double-sided image data, the double-sided printing control unit The double-sided image data is rotated 90 degrees clockwise or 90 degrees counterclockwise so that the row direction is parallel to the longitudinal direction of the double-sided image data, and then the image data is stored again in the image data storage means. Try to remember. Even with this configuration, it is possible to obtain the functions and effects of the present invention.

  In the embodiment of the present invention, the MFP 100 is configured to include each unit. However, a program that realizes each unit may be stored in a storage medium and the storage medium may be provided. In this configuration, the program is read by the image forming apparatus, and the image forming apparatus implements the respective units. In that case, the program itself read from the recording medium exhibits the effects of the present invention. Furthermore, it is also possible to provide a storage method for storing the steps executed by each means in a hard disk.

  As described above, the image forming apparatus according to the present invention is useful for a copying machine, a printer, and the like as well as a multifunction machine, and is a double-sided printed material having excellent readability when a double-sided document is printed on both sides. It is effective as an image forming apparatus capable of obtaining the above.

DESCRIPTION OF SYMBOLS 100 MFP 401 Display reception means 402 Image reading means 403 Image data storage means 404 Character arrangement determination means 405 Image forming means 406 Line direction detection means 407 Duplex printing control means 408 Paper feed cassette selection storage means

Claims (4)

In an image forming apparatus including an image forming unit that performs double-side printing on a sheet based on double-sided image data of an original,
A character arrangement determining means for determining whether or not the arrangement of characters in the front surface image data and the arrangement of characters in the back surface image data match when duplex printing is performed based on the double-sided image data;
When the arrangement of characters in the front image data matches the arrangement of characters in the back image data, the line direction of the character line composed of a plurality of characters in the image data is relative to the longitudinal direction of the image data. Row direction detection means for detecting whether the image is parallel or vertical with respect to either the front surface image data or the back surface image data;
A double-sided printing control unit that causes the image forming unit to perform double-sided printing so that the conveyance direction of the paper that is double-sided printed based on the double-sided image data is parallel to the line direction of the detected character line of the image data;
An image forming apparatus comprising: Further, the paper feed cassette identification information for identifying the paper feed cassette and the paper orientation information indicating whether the transport direction of the paper stored in the paper feed cassette is parallel or perpendicular to the longitudinal direction of the paper are stored in association with each other. A paper cassette selection storage means,
The double-sided printing control unit causes the image forming unit to perform double-sided printing under a condition in which the line direction of the detected character line of the image data matches the direction indicated by the paper orientation information in the paper feed cassette selection storage unit. The image forming apparatus according to claim 1, wherein double-sided printing is performed so that a sheet conveyance direction is parallel to a line direction of a character line of the image data. When the double-sided printing control unit detects that the line direction of the character line is parallel to the longitudinal direction of the image data, the double-sided printing control unit refers to the paper orientation information of the paper feed cassette selection storage unit, Is sent to the image forming means corresponding to the paper orientation information indicating that the paper is parallel to the longitudinal direction of the paper,
When it is detected that the line direction of the character line is perpendicular to the longitudinal direction of the image data, the paper feed cassette corresponding to the paper orientation information indicating that the paper transport direction is perpendicular to the longitudinal direction of the paper 3. The image forming apparatus according to claim 2, wherein the image forming unit causes the image forming unit to perform double-sided printing on the paper in the paper feed cassette corresponding to the paper feed cassette identification information by transmitting the identification information to the image forming unit. . Further, a sheet presence detection sensor for detecting whether or not a sheet in the sheet cassette exists is provided for each sheet cassette provided in the image forming apparatus,
When the duplex printing control means transmits predetermined paper cassette identification information to the image forming means, it uses the paper presence sensor of the paper cassette corresponding to the paper cassette identification information to use the paper in the paper cassette. Detect the presence of
If paper is present, the paper cassette identification information is transmitted to the image forming means,
When there is no sheet, a screen prompting the user to set the sheet in the manual feed tray in a predetermined direction in which the sheet conveyance direction is parallel to the line direction of the character line of the double-sided image data, or the sheet feeding The image forming apparatus according to claim 3, wherein a screen that prompts the user to replenish paper in the cassette is displayed.

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