JP2016224271A - Printing system, and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a serial tandem machine (printing system) or the like that, even when printing on both faces of multiple sheets of paper is done to produce a booklet, makes any difference in hue is hardly recognizable by users between two facing pages.SOLUTION: A printing system is a serial tandem type printing system that performs double-side printing, which is accomplished by different image forming units forming images of the first and second faces of each paper sheet. The printing system is equipped with an extracting unit that extracts objects contained in printing data, a hue assessing unit that compares objects, out of objects extracted by the extracting unit, used in each of the two facing pages of the booklet to be produced and makes assessment as to whether or not prescribed conditions for making the difference in hue between the facing pages recognizable, and an image formation control unit that performs control to use, if the prescribed conditions are found satisfied, the same image forming unit to be used for forming images on both of the facing pages.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a printing system and a printing method.

  In recent years, a printing system called a serial tandem machine in which two printing engines (image forming units) are connected in series has been developed. In a serial tandem machine, when performing double-sided printing, the upstream print engine that serves as the master prints on the first surface (for example, the front surface) of the paper, and the downstream print engine that serves as the slave then Printing is performed on the second side (for example, the back side) of the paper.

  In a normal printing system, it is necessary to perform double-sided printing with one printing engine, so after printing on the first side, it is necessary to reverse the paper and return it to the entrance side of the printing engine. Because you do not need to return the paper, you can print on both sides at high speed. An example of a serial tandem machine is disclosed in Patent Document 1.

JP 2012-58426 A

  However, in a serial tandem machine, both sides of a sheet of paper are printed by separate print engines, so depending on the degree of wear of each print engine, the print execution history, etc. There is a risk that a subtle difference may occur in the “color”. In particular, when a booklet is created by duplex printing on a plurality of sheets, each page of the spread pages is printed by a separate print engine, so that the user can easily recognize a difference in color.

  The present invention has been made in view of the above circumstances. In other words, the purpose is to provide a serial tandem machine (printing system) that makes it difficult for the user to recognize the color difference between pages of a spread page even when creating a booklet by duplex printing on multiple sheets of paper. And

  (1) A serial tandem printing system in which different image forming units form images on the first side and the second side of a sheet to perform duplex printing, and are included in print data to be printed. In the case of creating a booklet by double-side printing on a plurality of sheets based on the print data, and an extraction unit for extracting an object, among the objects extracted by the extraction unit, it is used for each spread page of the booklet The color determination unit that determines whether or not a predetermined condition for recognizing a color difference between the pages is satisfied, and the color determination unit determines that the predetermined condition is satisfied In this case, a printing system comprising: an image forming control unit that performs control to make the image forming unit that forms an image on each of the spread pages the same.

  (2) The color determination unit includes a case where the same object is included in each page of the spread page, a case where an inverted object is included in each page of the spread page, and the spread page. When the approximate color is included in the central portion of the printing system, the printing system according to (1) is determined to satisfy the predetermined condition in at least one of the cases.

  (3) A paper discharge control unit that selectively discharges either the first surface or the second surface of the paper after double-sided printing toward the upper surface, and according to the discharge results by the paper discharge control unit The printing system according to (1) or (2), further comprising: a paper gap setting unit that changes a paper gap between sheets that are continuously fed.

  (4) A paper discharge control unit that selectively discharges either the first surface or the second surface of the paper after double-sided printing toward the upper surface, and the image formation control unit is connected in series. By controlling the image of the page formed by each of the different image forming units and the paper discharge surface, the image forming unit that forms an image on each of the spread pages is made the same, (1) to (3) The printing system according to any one of the above.

  (5) A serial tandem printing method in which different image forming units form images on the first side and the second side of a sheet to perform double-sided printing, and are included in (a) print data to be printed And (b) when creating a booklet by double-side printing on a plurality of sheets based on the print data, among the objects extracted in step (a), Comparing the object used for each page of the page to determine whether a predetermined condition for recognizing a color difference between the pages is satisfied, and (c) determining the predetermined condition in step (b) A step of performing control to make the same image forming unit for forming an image on each of the spread pages when it is determined that the two pages are satisfied Printing method.

  (6) In the step (c), the same object is included in each page of the spread page, the inverted object is included in each page of the spread page, and the spread page The printing method according to (5), in which it is determined that the predetermined condition is satisfied in at least one of the cases where the approximate color is included in the central portion of the image.

  (7) (d) a step of selectively discharging either the first surface or the second surface of the paper after double-sided printing toward the upper surface; and (e) discharging in the step (d). The printing method according to (5) or (6), further including a step of changing a gap between sheets to be continuously fed according to a paper record.

  (8) (d) The method further includes a step of selectively discharging either the first surface or the second surface of the paper after double-side printing toward the upper surface, and in the step (c), (5) to (7), wherein the image forming unit that forms an image on each page of the spread pages is made the same by controlling the image of the page formed by each of the different image forming units in series and the paper discharge surface. The printing method as described in any one of.

  According to the present invention, when a booklet is created using a serial tandem machine, when there is a possibility that a difference in color may be recognized on a spread page, image formation for forming an image on each page of the spread page Make the parts the same. This makes it difficult for the user to recognize the color difference between the pages of the spread pages.

1 is a schematic configuration diagram of a printing system. It is a figure which shows the network connection with PC. It is a block diagram which shows the function structural example of a main | base station. It is a flowchart of a printing control process. It is a figure for demonstrating the basic control at the time of producing a booklet. It is a figure for demonstrating the 1st condition from which a user can recognize the difference in color on a spread page. It is a figure for demonstrating the 2nd condition by which a user can recognize the difference in color on a spread page. It is a figure for demonstrating the 3rd condition by which a user can recognize the difference in color on a spread page. It is an example of the graph when it is determined that the third condition is satisfied. It is an example of the graph when it is determined that the third condition is not satisfied. It is a figure for demonstrating the control in case a difference in color can be recognized by a spread page (2, 3 pages) when producing a booklet. It is a figure for demonstrating the control in case a difference in a color can be recognized by a spread page (2, 3 pages, 4 pages, 5 pages) when producing a booklet. It is a flowchart of an image formation process (master). It is a figure for demonstrating the conditions when expanding the space | interval of a paper. It is a figure which shows the space between normal paper and the paper spread. 6 is a flowchart of image formation processing (child device).

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

[Printing system 100]
FIG. 1 is a schematic configuration diagram of a printing system 100. FIG. 2 is a diagram illustrating a network connection with the PC 200. Hereinafter, a schematic configuration of the printing system 100, particularly a hardware configuration, will be described with reference to FIGS.

(1) Overall Configuration The printing system 100 according to the present embodiment is a series tandem machine in which two printing engines (two image forming apparatuses 110 and 130 shown in FIG. 1) are connected in series.

  As shown in FIGS. 1 and 2, an image forming apparatus (hereinafter simply referred to as “parent device”) 110 as a parent device and an image forming apparatus (hereinafter simply referred to as “child device”) 130 as a child device. An intermediate reversing device 120 for reversing a recording material such as a sheet output from the master unit 110 is connected between them. An output reversing device 140 that reverses the paper output from the slave unit 130 is connected to the downstream side of the slave unit 130. Therefore, in the example shown in FIGS. 1 and 2, the master unit 110, the intermediate reversing device 120, the slave unit 130, and the output reversing device 140 are continuously arranged in the order shown in the drawing from the upstream side in the paper conveyance direction. ) Connected.

(2) Base unit 110
The master unit 110 is an image forming apparatus that controls the entire printing system 100 and functions as a master unit of a serial tandem machine. For example, base unit 110 forms (prints) an image on the first side of paper P when performing double-sided printing.

  In order to realize the function as the master unit, as shown in FIG. 1, the master unit 110 includes a control unit 111, a communication unit 112, a paper storage unit 113, an image forming unit 114, a fixing unit 115, And an operation panel unit 116. The units 111 to 116 are connected to each other via signal lines (such as a bus) for exchanging signals.

(2-1) Control unit 111
The control unit 111 integrally controls the units 112 to 116 inside the base unit 110, the transport path inside the base unit 110 that transports the paper P, the intermediate reversing device 120, and the like. At the same time, the control unit 111 operates the devices 120 to 140 in cooperation with each other by sending a command (signal) to the slave unit 130.

  For example, the control unit 111 includes a CPU (Central Processing Unit), a memory, and a storage (not shown).

  The CPU is a control circuit composed of a multi-core processor or the like that executes various controls and various arithmetic processes according to a program, and each function of the parent device 110 is exhibited by the CPU executing a corresponding program. .

  The memory is a high-speed accessible main storage device that temporarily stores programs and data as a work area. As the memory, for example, a DRAM (Dynamic Random Access Memory), an SDRAM (Synchronous Dynamic Access Memory), an SRAM (Static Random Access Memory), or the like is adopted.

  The storage is a large-capacity auxiliary storage device that stores various programs including an operating system and various data. For the storage, for example, a hard disk, a solid state drive, a flash memory, a ROM, or the like is employed.

(2-2) Communication unit 112
The communication unit 112 is an interface for communicating with other devices. The communication unit 112 transmits and receives various setting values and various information necessary for operation timing control to and from the child device 130.

(2-3) Paper storage unit 113
The paper storage unit 113 is a paper supply tray that stores the paper P. The paper P is conveyed from the paper storage unit 113 to the image forming unit 114 by driving a paper feed roller or the like. The paper storage unit 113 does not need to be stored in the housing of the parent device 110 and may be installed as an external paper feeding device independent of the parent device 110.

(2-4) Image forming unit 114
The image forming unit 114 forms a toner image by an image forming process such as an electrophotographic method and transfers the toner image onto the paper P. For example, the image forming unit 114 employs a tandem system having an independent photosensitive drum for each color of C (cyan), M (magenta), Y (yellow), and K (black). The toner images of the respective colors formed on the photosensitive drums (C, M, Y, K) are sequentially transferred onto the intermediate transfer belt, and the toner images (colors) in which the layers of the respective colors (C, M, Y, K) are superimposed. Image) is formed on the intermediate transfer belt. Here, the intermediate transfer belt is an endless belt, is wound around a plurality of rollers, and is supported so as to be able to run. The toner image formed on the intermediate transfer belt is transferred onto the paper P by applying a bias having a polarity opposite to that of the toner to the transfer roller.

  However, the image forming unit 114 may adopt a rotary method instead of the tandem method as described above. Further, methods other than the electrophotographic method (ink jet method, impact method, thermal transfer method, etc.) may be adopted.

(2-5) Fixing unit 115
The fixing unit 115 fixes the toner image transferred on the paper P onto the paper P by heating. For example, the fixing unit 115 presses a heating member, which is a heating source, to the pressure member. As a result, heat and pressure are applied to the paper P at the fixing nip portion, and the toner image is melted and fixed.

(2-6) Operation panel unit 116
The operation panel unit 116 includes a display unit (not shown) such as a display and a transparent operation panel attached to the display surface side of the display unit. The operation panel unit 116 specifies a touch position corresponding to the XY coordinates of the image displayed on the display unit, converts the touch position into coordinates, and outputs the coordinate. The operation panel unit 116 includes a pressure-sensitive or electrostatic input detection element. Input to the operation panel unit 116 is performed by an intuitive touch operation. For example, input is performed by an operation of touching a part of a key (or button, icon, toolbar, or predetermined area) displayed on the display with a finger or a stylus (pen). The operation panel unit 116 may include physical keys such as a numeric keypad, a start key, and a stop key.

(3) Intermediate reversing device 120
The intermediate reversing device 120 is controlled by the master unit 110 and carries and reverses the paper output from the master unit 110. In the case of single-sided printing, the paper output from the master unit 110 is conveyed to the slave unit 130 without being inverted. In the case of double-sided printing, the front and back sides of the sheet output from the master unit 110 are inverted. Transport to 130. In order to realize this function, the intermediate reversing device 120 includes a paper transport unit 123, a reversing unit 124, and a switch unit 125, as shown in FIG. The units 123 to 125 and the control unit 111 of the base unit 110 are connected to each other via signal lines (such as a bus) for exchanging signals. Hereinafter, conveying the paper output from the parent device 110 to the child device 130 without reversing the paper is referred to as “FaceUp”. In addition, reversing the front and back of the paper output from the parent device 110 and transporting it to the child device 130 is referred to as “FaceDown”.

(3-1) Paper transport unit 123
The paper transport unit 123 transports the paper output from the master unit 110 along the transport path in the intermediate reversing device 120. In the case of single-sided printing, the paper transport unit 123 transports the paper transmitted from the parent device 110 to the slave device 130 as it is (without passing through the reversing unit 124). In the case of duplex printing, the paper transport unit 123 transports the paper output from the master unit 110 to the reversing unit 124.

(3-2) Inversion unit 124
The reversing unit 124 is configured by a switchback path formed in a substantially vertical (gravity) direction. The sheet is fed into the switchback path, and the sheet can be reversed to reverse the sheet.

(3-3) Switch unit 125
The switch unit 125 has a mechanism for switching whether the paper output from the parent device 110 is reversed through the reversing unit 124 or conveyed without passing through the reversing unit 124.

(4) Handset 130
The slave unit 130 is an image forming apparatus that operates according to an instruction from the master unit 110, and functions as a slave unit of the serial tandem unit. For example, the slave unit 130 forms (prints) an image on the second side opposite to the first side of the paper P when performing duplex printing.

  As the slave unit 130, an image forming apparatus having the same hardware configuration as that of the master unit 110 may be used, or an image forming apparatus having a part of the hardware configuration may be used.

  In order to realize the function as a slave unit, the slave unit 130 includes a control unit 131, a communication unit 132, an image forming unit 134, and a fixing unit 135, as shown in FIG. The units 131 to 132 and 134 to 135 are connected to each other via signal lines (bus or the like) for exchanging signals.

(4-1) Control unit 131
The control unit 131 integrally controls the units 132, 134, 135 inside the slave unit 130, the transport path inside the slave unit 130 that transports the paper P, the output reversing device 140, and the like. For example, the control unit 131 functions as a paper discharge control unit that controls the output reversing device 140, and can selectively discharge either the first side or the second side of the paper after double-sided printing toward the upper surface. .

  The control unit 131 includes a CPU, a memory, and a storage (not shown). Since the CPU, memory, and storage are the same as those of the control unit 111 of the parent device 110, descriptions thereof are omitted.

(4-2) Communication unit 132, image forming unit 134, fixing unit 135
In addition, the communication unit 132, the image forming unit 134, and the fixing unit 135 have the same functions as the communication unit 112, the image forming unit 114, and the fixing unit 115 of the parent device 110, respectively, so that the description is omitted in order to avoid duplication. Is omitted.

(5) Output inverter 140
The output reversing device 140 is controlled by the slave unit 130 and carries and reverses the paper output from the slave unit 130. In order to realize this function, the output reversing device 140 includes a paper transport unit 143, a reversing unit 144, and a switch unit 145, as shown in FIG. The units 143 to 145 and the control unit 131 of the slave unit 130 are connected to each other via a signal line (bus or the like) for exchanging signals. Hereinafter, discharging the paper output from the slave unit 130 onto the discharge tray 150 without inverting the front and back is referred to as “FaceUp”. In addition, turning the paper output from the slave unit 130 upside down and discharging the paper onto the paper discharge tray 150 is referred to as “FaceDown”.

(5-1) Paper transport unit 143
The paper transport unit 143 transports the paper output from the master unit 110 along the transport path in the output reversing device 140. In the case of FaceUp, the sheet transport unit 143 discharges the sheet transmitted from the slave unit 130 onto the sheet discharge tray 150 as it is (without passing through the reversing unit 144). In the case of FaceDown, the paper transport unit 143 transports the paper output from the slave unit 130 to the reversing unit 144.

(5-2) Inversion unit 144 and switch unit 145
In addition, the reversing unit 144 and the switch unit 145 have the same functions as the reversing unit 124 and the switch unit 125 of the intermediate reversing device 120, respectively.

  The printing system 100 having the above hardware configuration is normally connected to a client computer (hereinafter referred to as “PC”) 200 as an external device via a network 50 as shown in FIG. The

  The PC 200 is a general computer and can transmit a print job to the printing system 100. The PC 200 performs print settings for each print job. For this reason, a printer driver (program) suitable for the printing system 100 is installed in the PC 200. The user transmits a print job to the printing system 100 using this printer driver. Here, the print job includes print data to be printed (for example, PDL data) and print settings (hereinafter referred to as “job ticket”). The job ticket includes information for designating the number of copies to be printed, paper size, duplex / single-sided, color / monochrome, and the like.

  Although only one PC 200 is shown in FIG. 2, a plurality of PCs 200 may be connected to the network 50, and in this case, each PC 200 can transmit a print job to the printing system 100.

  The network 50 is realized by a computer network such as a LAN (Local Area Network).

[Functional configuration of base unit 110]
Next, the functional configuration of base unit 110 will be described.

  FIG. 3 is a block diagram illustrating a functional configuration example of the parent device 110. As illustrated in FIG. 3, the control unit 111 of the parent device 110 includes an extraction unit 310, a color determination unit 320, an image formation control unit 330, and a paper interval setting unit 340.

  The extraction unit 310 extracts an object included in print data to be printed.

  Here, the objects are distinguished by attributes such as “text” representing characters, “graphics” representing figures and lines, “images” representing images, and each object has object information.

  The object information includes information indicating the attribute of the object (attribute information) and different types of information for each attribute. For example, in the case of an object having the “text” attribute, information indicating the drawing position (coordinates), font name, character code, character size, character color, and the like is included in the object information. If the object has a "graphic" attribute, the position of the point (coordinates), line attributes (line thickness, color, broken line, solid line, etc.), attributes of the area enclosed by the line (color, pattern, etc.), etc. Is included in the object information. In the case of an object having the “image” attribute, the object information includes information indicating a drawing position (coordinates), vertical and horizontal display sizes (or vertical and horizontal resolutions and enlargement ratios), and the like.

  When creating a booklet by duplex printing on a plurality of sheets, the color determination unit 320 compares the objects used for each page that becomes a spread page of the booklet among the objects extracted by the extraction unit 310. Determine whether the user can recognize the difference in color between pages. Generally, it is known that a difference in color is recognized between adjacent images unless the color difference ΔE is 0.8 or less. However, it is not realistic to print so that the color difference ΔE is suppressed to 0.8 or less between images formed by two different image forming units 114 and 134, respectively. In this embodiment, instead of suppressing the color difference ΔE between images to 0.8 or less, the color determination unit 320 is adjacent depending on whether or not a predetermined condition (details will be described later) is satisfied. It is determined whether a difference in color can be recognized between images, that is, between pages of a booklet.

  Then, when it is determined that the color difference can be recognized between the pages that are the spread pages of the booklet, the image formation control unit 330 forms an image on each of the spread pages. Control to make the same part.

  The sheet interval setting unit 340 changes the sheet interval of sheets to be continuously fed in accordance with the sheet discharge result by the output inverting device 140. The paper discharge result here refers to a relative relationship between the previous sheet discharge state (scheduled) and the current sheet discharge state (scheduled).

  Note that the extraction unit 310, the color determination unit 320, the image formation control unit 330, and the paper interval setting unit 340 each read and execute a program installed in the storage by the CPU in the parent device 110. It is realized by. However, the functional units 310 to 340 are not limited to this, and may be realized by hardware such as an ASIC.

[Operation of Printing System 100]
Next, a characteristic operation of the printing system 100 according to the present embodiment will be described.

(1) Print Control Process FIG. 4 is a flowchart of the print control process. The print control process is a process for controlling printing in the printing system 100 (serial tandem machine), and is executed by the master unit 110. FIG. 5 is a diagram for explaining basic control when a booklet is created. FIG. 6 is a diagram for describing a first condition that allows a user to recognize a color difference on a spread page. FIG. 7 is a diagram for describing a second condition that allows a user to recognize a color difference in a spread page. FIG. 8 is a diagram for explaining a third condition that allows the user to recognize a color difference on the spread page. FIG. 9 is an example of a graph when it is determined that the third condition is satisfied. FIG. 10 is an example of a graph when it is determined that the third condition is not satisfied. FIG. 11 is a diagram for explaining control when a difference in color can be recognized on the spread pages (2, 3) when creating a booklet. FIG. 12 is a diagram for explaining control when a difference in color can be recognized on the spread pages (2, 3, 4, 5) when creating a booklet.

  Hereinafter, the print control process will be described with reference to FIGS.

  Each time the master device 110 receives a print job transmitted from the PC 200, the master device 110 starts the print control process shown in FIG. However, the timing of starting the print control process is not limited to this, and the print control process may be started at a timing when an instruction such as copying is received from the user via the operation panel unit 116.

(Step S101)
When the print control process is started, the control unit 111 of the parent device 110 refers to a job ticket included in the received print job and determines whether double-sided printing is designated. However, when an instruction for copying or the like is received from the operation panel unit 116, the control unit 111 determines whether the instruction includes designation for duplex printing.

  Then, when double-sided printing is designated (step S101: YES), the control unit 111 advances the process to step S103. On the other hand, if double-sided printing is not designated (step S101: NO), the control unit 111 advances the process to step S102.

(Step S102)
When the process proceeds to step S102, the control unit 111 functions as the image formation control unit 330, and prints (single-sided printing) all pages of the print data included in the received print job with the parent device 110. Specifically, the control unit 111 analyzes the print data and converts it into intermediate data, and then generates raster data by normal rasterization processing (including screen processing) and outputs the raster data to the image forming unit 114. The image forming unit 114 forms a toner image for each page based on the raster data, and sequentially transfers the toner image to the paper fed from the paper storage unit 113. The sheet on which the image is formed in this manner passes through the fixing unit 115, the intermediate reversing device 120, the slave unit 130, and the output reversing device 140 without being reversed in accordance with the instruction of the control unit 111, and the paper discharge tray. The sheet is discharged onto 150.

  Note that all pages may be printed by the slave unit 130 instead of the master unit 110.

  When printing of all pages is completed, the control unit 111 ends the print control process.

(Step S103)
When the process proceeds from step S101 to step S103, the control unit 111 saves the job ticket included in the print job in a memory or storage.

(Step S104)
The control unit 111 generates information to be included in the page ticket based on the information included in the job ticket, and stores it in the memory or storage. Here, the page ticket refers to a print setting for each page (or paper). In the present embodiment, there are a page ticket for the parent device and a page ticket for the child device.

  More specifically, the control unit 111 specifies information for specifying “FaceUp” and “FaceDown” of the sheet by the intermediate reversing device 120 based on information included in the job ticket (hereinafter referred to as “reversal setting information”). To generate). For example, when double-sided printing is specified in the job ticket, since the slave unit 130 forms an image on the second side of the sheet after the master unit 110 forms an image on the first side of the sheet, the control unit 111 generates inversion setting information for designating “FaceDown”.

  Further, based on the information included in the job ticket, the control unit 111 specifies information for designating “FaceUp” and “FaceDown” of the paper by the output reversing device 140 (hereinafter referred to as “discharge surface setting information”). Generate. The paper discharge surface setting information can be changed (rewritten) in units of paper (sheets), and information specifying “FaceUp” is stored as the paper discharge surface setting information in the initial setting.

(Step S105)
The control unit 111 functions as the extraction unit 310 and extracts all objects from the print data (PDL data) included in the received print job. At the same time, the control unit 111 records object information of each object for each page.

  The object information is obtained by a normal analysis method for PDL data. Further, the control unit 111 records the generated object information in association with the job ticket and page ticket stored in steps S103 and S104.

(Step S106)
Next, the control unit 111 determines a target page to be subjected to rasterization processing (including screen processing). In the present embodiment, rasterization processing or the like is performed in the order of pages of print data. However, as shown in FIG. 5, when creating a booklet by duplex printing on a plurality of sheets, rasterization processing or the like is performed for each page for forming an image on each sheet. That is, in the example shown in FIG. 5, since one page is printed on both sides of the paper, each page is subjected to rasterization processing or the like.

  Then, the control unit 111 determines whether or not the page determined as a target to be subjected to the rasterizing process is to be printed on the first sheet of the booklet. Specifically, the control unit 111 plans to print on the first sheet (first sheet) of the booklet when rasterization processing or the like has not yet been performed for any page of the print data. It is judged that. On the other hand, the control unit 111 determines that printing is scheduled for the second and subsequent sheets if rasterization processing or the like has already been performed on at least the page scheduled to be printed on the first sheet.

  When the page to be subjected to the rasterizing process or the like is to be printed on the first sheet (step S106: YES), the control unit 111 skips steps S107 to S109 and advances the process to step S110. . In parallel with this, the control unit 111 actually performs rasterization processing or the like on the print data of the page scheduled to be printed on the first sheet, and stores the raster data generated thereby in the memory or storage. Keep it.

  On the other hand, when the page to be subjected to the rasterizing process or the like is not scheduled to be printed on the first sheet (step S106: NO), the control unit 111 advances the process to step S107.

(Step S107)
The control unit 111 reads print data and object information of a page that becomes a spread page when the booklet is completed from the memory or the storage. For example, as illustrated in FIG. 5, when the pages to be subjected to the rasterizing process or the like are pages scheduled to be printed on the second sheet (the third and fourth pages), the control unit 111 sets 2 The object information is read out by comparing the print data of the third page of the sheet and the second page of the sheet immediately before becoming the spread page. Similarly, when the page to be rasterized is the page to be printed on the third sheet (the fifth and sixth pages), the control unit 111 opens the fifth page of the third sheet. The object information is read using the print data of the fourth page of the sheet immediately before the page as a comparison target.

(Step S108)
The control unit 111 functions as the color determination unit 320, and determines whether a predetermined condition that allows the user to recognize the color difference in the spread page satisfies. For example, the control unit 111 determines that the predetermined condition is satisfied when at least one of the following first to third conditions is satisfied, and satisfies the first to third conditions. If neither is satisfied, it is determined that the predetermined condition is not satisfied.

(A) First condition The control unit 111 compares the object information of the spread page read in step S107, and determines whether the same object is included in the spread page. For example, as shown in FIG. 6, when the same logo M1 is present on the spread page, the user can easily recognize the color difference, and therefore it is determined that the first condition is satisfied. Note that the position of the logo M1 is not limited to the position shown in FIG. 6, and it is determined that the first condition is satisfied even if the logo M1 exists at different positions on both pages.

(B) 2nd condition The control part 111 compares the object information of the spread page read at step S107, and judges whether the object reversed by the spread page is contained. For example, as shown in FIG. 7, when there is a mark M <b> 2 that is reversed on a spread page, the user can easily recognize the color difference, and therefore it is determined that the second condition is satisfied. Here, as a method for determining whether the object is an inverted object, for example, in the case of an object having the “graphic” attribute, it can be determined by comparing the position (coordinate) of the point, the direction of the line, and the like. Further, in the case of an object having an “image” attribute, the determination can be made by comparing the CMYK values of the respective pixels. Note that the position of the mark M2 is not limited to the position shown in FIG. 7, and it is determined that the second condition is satisfied even if the mark M2 exists at different positions on both pages.

(C) Third condition The control unit 111 performs rasterization processing (including screen processing) on the print data of the spread page read in step S107, compares the generated raster data, and compares the generated raster data. Judge whether approximate color is included in the center part. However, for pages for which raster data has already been generated, they are read out from the memory or storage for comparison without any new rasterization processing or the like.

  Note that the center portion of the spread page refers to a predetermined area C as shown in FIG. As a method for determining whether or not the approximate color is included in the center portion of the spread page, for example, it can be determined using graphs as shown in FIGS.

  9 and 10, the horizontal axis indicates the position X of the pixels arranged in the main scanning direction, and the vertical axis indicates the density value Y. The position of X = 0 on the horizontal axis is set as the boundary position of the spread page. The density value Y on the vertical axis is the average value of CMYK values of all the pixels arranged in the sub-scanning direction (pixels having the same position X in the main scanning direction).

  As shown in the graph of FIG. 9, when there is no sudden change in the density value Y between adjacent pixels in the predetermined region C (that is, when the differential value is smaller than the predetermined threshold), the control unit 111 Then, it is determined that the approximate color is included in the center portion of the spread page.

  On the other hand, as shown in the graph of FIG. 10, when a sudden change in the density value Y is observed between adjacent pixels in the predetermined region C (that is, when the differential value is equal to or greater than a predetermined threshold value), the control unit No. 111 determines that the approximate color is not included in the center portion of the spread page.

  If at least one of the first condition to the third condition as described above is satisfied (step S108: YES), the control unit 111 determines that the predetermined condition is satisfied, and performs the process. Proceed to S109. On the other hand, when none of the first condition to the third condition as described above is satisfied (step S108: NO), the control unit 111 determines that the predetermined condition is not satisfied, and the process proceeds to step S110. Proceed.

(Step S109)
The control unit 111 changes the sheet discharge surface setting information in order to switch between “FaceUp” and “FaceDown” of the paper by the output reversing device 140. For example, if the paper discharge surface setting information applied to the previous sheet stored in the memory or storage is “FaceUp”, the paper discharge surface setting information applied to the current sheet is rewritten to “FaceDown”. On the other hand, if the paper discharge surface setting information applied to the previous sheet stored in the memory or storage is “FaceDown”, the paper discharge surface setting information applied to the current sheet is rewritten to “FaceUp”.

(Step S110)
The control unit 111 reads the latest paper discharge surface setting information from the memory or the storage, and determines whether or not “FaceDown”.

  When the latest paper discharge surface setting information is “FaceDown” (step S110: YES), the control unit 111 advances the process to step S113. On the other hand, when the latest discharge surface setting information is “FaceUp” (step S110: NO), the control unit 111 advances the process to step S111.

(Step S111)
The control unit 111 performs control to form the surface image on the parent device 110.

  Specifically, the control unit 111 functions as the image formation control unit 330, reads inversion setting information and paper discharge surface setting information from the memory or storage, and generates a page ticket for the master unit including these pieces of information. Then, the control unit 111 starts control of the image forming unit 114 based on the generated page ticket for the parent device, and transmits the front surface image to the image forming unit 114 of the parent device 110. Here, the front image refers to raster data of the previous page (page order determined in advance in print data) among the pages subjected to rasterization processing in step S106.

(Step S112)
The control unit 111 performs control to form the back image in the slave unit 130.

  Specifically, the control unit 111 functions as the image formation control unit 330, reads out the paper discharge surface setting information from the memory or the storage, and generates a page ticket for the slave unit including this information. Then, the control unit 111 transmits the generated page ticket for the child device to the child device 130. At the same time, the control unit 111 transmits the back image to the image forming unit 134 of the slave unit 130. Here, the back image refers to raster data of a later page (page order determined in advance in print data) among the pages subjected to rasterization processing in step S106.

  Thereafter, the control unit 111 advances the process to step S115.

(Step S113)
On the other hand, when the process proceeds from step S <b> 110 to step S <b> 113, the control unit 111 performs control to form the back image on the parent device 110.

  Specifically, the control unit 111 functions as the image formation control unit 330, reads inversion setting information and paper discharge surface setting information from the memory or storage, and generates a page ticket for the master unit including these pieces of information. Then, the control unit 111 starts control of the image forming unit 114 based on the generated page ticket for the base unit, and transmits the back image to the image forming unit 114 of the base unit 110.

(Step S114)
The control unit 111 performs control for forming the surface image in the slave unit 130.

  Specifically, the control unit 111 functions as the image formation control unit 330, reads out the paper discharge surface setting information from the memory or the storage, and generates a page ticket for the slave unit including this information. Then, the control unit 111 transmits the generated page ticket for the child device to the child device 130. At the same time, the control unit 111 transmits the surface image to the image forming unit 134 of the slave unit 130.

  Thereafter, the control unit 111 advances the process to step S115.

(Step S115)
The control unit 111 further determines whether there is a target page (next page) to be subjected to rasterization processing or the like. Specifically, the control unit 111 determines that there is a next page when there is a page that has not been subjected to rasterization processing or the like. On the other hand, the control unit 111 determines that there is no next page when rasterization processing or the like has already been performed for all pages of the print data.

  If the control unit 111 determines that there is a next page (step S115: YES), the control unit 111 returns the process to step S106, and performs the processes of steps S106 to S115 until there is no page to be subjected to the rasterizing process. repeat. On the other hand, when determining that there is no next page (step S115: NO), the control unit 111 ends the print control process.

  In the above print control process, the same image forming unit for forming an image on each page of the spread page is used only when there is a possibility that the user may recognize a color difference in the spread page of the booklet. . Such control not only makes it difficult for the user to recognize the difference in color between the two spread pages, but also makes it possible to minimize the switching between “FaceUp” and “FaceDown” in the output inversion device 140. .

  Specifically, an example shown in FIG. 5 will be described. In FIG. 5, it is determined in step S108 that the difference in color between the second and third spread pages is difficult to recognize (does not satisfy the predetermined condition), and the fourth and fifth spread pages are also determined. In this example, it is determined that the difference in color is difficult to recognize. In this case, as shown in FIG. 5, the second page and the third page are formed by different image forming units (slave units, master units), and the fourth page and the fifth page are also different image forming units (slave units). , The master unit) forms an image. According to such control, the difference in color is not easily recognized in the spread pages, and there is no switching between “FaceUp” and “FaceDown” in the output inverting device 140, so that the control does not become complicated.

  Another example will be described with reference to FIG. In FIG. 11, it is determined in step S108 that a difference in color can be recognized between the second and third spread pages (satisfies a predetermined condition), and the fourth and fifth spread pages are displayed. In this example, it is determined that the difference in color is difficult to recognize. In this case, as shown in FIG. 11, the second and third pages are formed by the same image forming unit (child device), and the fourth and fifth pages are different image forming units (parent device, child device). Machine). According to such control, the difference in color is difficult to recognize in the spread pages, and the control is complicated because “FaceUp” and “FaceDown” in the output inversion device 140 are not switched between the second sheet and the third sheet. You do n’t have to.

  Still another example will be described with reference to FIG. FIG. 12 shows that, in step S108, it is determined that the difference in color can be recognized between the second and third spread pages (satisfies a predetermined condition), and the fourth and fifth spread pages are also displayed. This is an example in which it is determined that a difference in color can be recognized. In this case, as shown in FIG. 12, the second page and the third page are formed by the same image forming unit (slave unit), and the fourth page and the fifth page are also the same image forming unit (master unit). As a result, an image is formed. In this way, if necessary, the output reversing device 140 can switch between “FaceUp” and “FaceDown” for each sheet, and a high-quality booklet can be created.

(2) Image formation processing (master unit)
Next, FIG. 13 is a flowchart of the image forming process (master unit). Note that the image forming process (master device) is executed in the master device 110 in the same manner as the print control process described above.

  FIG. 14 is a diagram for explaining conditions for increasing the space between sheets. FIG. 15 is a diagram illustrating a normal paper space and a widened paper space.

  Hereinafter, the procedure of the image forming process (master) will be described with reference to FIGS.

  The control unit 111 of the master unit 110 starts an image forming process (master unit) every time the process of step S111 or S113 is executed in the print control process.

(Step S201)
When the control unit 111 starts the image forming process (master), the image (front image, back image) transmitted to the image forming unit 114 in step S111 or S113 is the first sheet (the first sheet of the booklet). To determine if it is going to be printed.

  If the image transmitted to the image forming unit 114 in step S111 or S113 is to be printed on the first sheet (step S201: YES), the control unit 111 omits steps S202 to S203 and performs processing. Advances to step S204. On the other hand, when the image transmitted to the image forming unit 114 in step S111 or S113 is not scheduled to be printed on the first sheet (step S201: NO), the control unit 111 advances the process to step S202.

(Step S202)
The control unit 111 functions as a paper gap setting unit 340 and refers to the paper discharge surface setting information included in the page ticket for the master unit, and whether the content is the same as the paper discharge surface setting information applied to the previous sheet. Determine.

  For example, when the discharge surface setting information applied to the previous sheet is “FaceUp” and the discharge surface setting information applied to the current sheet is “FaceUp”, the control unit 111 Judgment is the same. Similarly, when (B) the paper discharge surface setting information applied to the previous sheet is “FaceDown” and the paper discharge surface setting information applied to the current sheet is “FaceDown”, both are determined to be the same. To do. On the other hand, if (C) the paper discharge surface setting information applied to the previous sheet is “FaceUp” and the paper discharge surface setting information applied to the current sheet is “FaceDown”, the control unit 111 Are not the same. Similarly, when (D) the paper discharge surface setting information applied to the previous sheet is “FaceDown” and the paper discharge surface setting information applied to the current sheet is “FaceUp”, the two are not the same. Judge.

  If both are the same (step S202: YES), the controller 111 advances the process to step S204. On the other hand, when the two are not the same (step S202: NO), the control unit 111 advances the process to step S203.

(Step S203)
Continuing from step S202, the control unit 111 functions as a paper gap setting unit 340, refers to the paper discharge surface setting information included in the page ticket for the master unit, and the paper discharge surface setting information applied to the current sheet. Is “FaceDown”.

  Then, when the paper discharge surface setting information applied to the current sheet is “FaceDown” (step S203: YES), the control unit 111 advances the process to step S204. On the other hand, when the paper discharge surface setting information applied to the current sheet is not “FaceDown” (step S203: NO), the control unit 111 advances the process to step S205.

(Step S204)
When the process proceeds to step S204, the control unit 111 functions as the sheet interval setting unit 340 and sets the sheet to be fed between normal sheets. In accordance with this setting, the control unit 111 feeds paper after a normal paper interval time has elapsed since the previous paper feed (one sheet before). Note that the process of step S204 is executed only in the cases shown in FIGS. For example, when (A) the paper discharge surface setting information is maintained as “FaceUp”, the subsequent paper does not catch up with the preceding paper without increasing the interval between the papers. Therefore, in step S204, the sheet is fed between normal sheets. The same applies when (B) the paper discharge surface setting information is maintained as “FaceDown” and (C) the paper discharge surface setting information is changed from “FaceUp” to “FaceDown”.

(Step S205)
On the other hand, when the process proceeds to step S205, the control unit 111 functions as the paper interval setting unit 340 and sets the paper to be fed with a paper interval wider than the normal paper interval. Then, according to this setting, the control unit 111 feeds paper by extending the paper interval time. As shown in FIG. 14D, if paper is fed between normal sheets, the following sheet catches up while the preceding sheet is passed through the reversing unit 124. For this reason, in step S205, the control unit 111 feeds paper between sheets wider than a normal sheet as shown in FIG.

(Step S206)
When the process proceeds to step S206, the image forming unit 114 forms a toner image based on the raster data sent from the control unit 111 in step S111 or S113, and sequentially forms the sheets fed under the control of step S204 or S205. Transcript. The sheet on which the image is thus formed passes through the fixing unit 115 and is output to the intermediate reversing device 120 in accordance with an instruction from the control unit 111.

(Step S207)
The control unit 111 controls the intermediate inversion device 120 with reference to the inversion setting information included in the page ticket for the master unit. In this image forming process (parent device), since double-sided printing (that is, reverse setting information is “FaceDown”) is designated, the control unit 111 controls the switch unit 125 of the intermediate reversing device 120 to control the parent device. The paper output from 110 is reversed through the reversing unit 124.

(Step S208)
The control unit 111 controls the sheet conveying unit 123 of the intermediate reversing device 120 to output the reversed sheet to the slave unit 130.

  Thereafter, the control unit 111 ends the image forming process (parent device).

  Through the image forming process (master), the master 110 can form (print) an image on the first surface of the paper. In addition, since the paper feeding interval is adjusted as appropriate so that the paper following the preceding paper does not catch up, abnormal conveyance of the paper hardly occurs, and the conveyance of the paper is also efficient.

(3) Image formation processing (child device)
Next, FIG. 16 is a flowchart of the image forming process (child device). Note that the image forming process (child device) is executed in the child device 130.

  Hereinafter, with reference to FIG. 16, the procedure of the image forming process (child device) will be described.

  The control unit 131 of the slave unit 130 starts an image forming process (slave unit) each time the process of step S112 or S114 is executed in the print control process.

(Step S301)
The control unit 131 receives the page ticket and the image (front image, back image) for the child device transmitted from the parent device 110 in step S112 or S114 via the communication unit 132.

(Step S302)
When the process proceeds to step S <b> 302, the control unit 131 controls the conveyance path inside the slave unit 130 and feeds the paper output from the intermediate reversing device 120 toward the transfer position of the image forming unit 134.

(Step S303)
The image forming unit 134 forms a toner image based on the image (front image, back image) received in step S301, and sequentially transfers it to the fed paper under the control of step S302. The sheet on which the image is thus formed passes through the fixing unit 135 and is output to the output reversing device 140 in accordance with an instruction from the control unit 131.

(Step S304)
The control unit 131 refers to the paper discharge surface setting information included in the page ticket for the child device and determines whether it is “FaceDown”.

  Then, when the paper discharge surface setting information is “FaceDown” (step S304: YES), the control unit 131 advances the process to step S305. On the other hand, when the paper discharge surface setting information is not “FaceDown” (step S304: NO), the control unit 131 advances the process to step S306.

(Step S305)
The control unit 131 controls the switch unit 145 of the output inversion device 140 to invert the paper output from the slave unit 130 through the inversion unit 144.

(Step S306)
The control unit 131 controls the paper transport unit 143 of the output reversing device 140 to discharge the paper onto the paper discharge tray 150.

  Thereafter, the control unit 131 ends the image forming process (child device).

  Through the above image forming process (child device), the child device 130 can form (print) an image on the second surface of the sheet. As a result, a booklet printed on both sides of a plurality of sheets can be created as in the examples shown in FIGS.

  For example, if the above-described image forming process (master unit and slave unit) is executed, after the image is formed on the second surface of the second sheet as shown in the example of FIG. The paper can be discharged after the paper discharge surface setting information is “FaceDown”. At this time, the master device 110 prints the image of the fourth page, and the slave device 130 prints the image of the third page. By such control, the second page and the third page can be printed by the same image forming unit, and a printed matter (booklet) arranged in the page order is formed on the paper discharge tray 150.

  Note that each processing unit in each flowchart described above is divided according to the main processing contents in order to facilitate understanding of the printing system 100. The invention of the present application is not limited by the method of classification of the processing steps and the names thereof. The processing performed in the printing system 100 can be divided into more processing steps. One processing step may execute more processes.

<Modification>
Moreover, said embodiment intends to illustrate the summary of this invention, and does not limit this invention. Many alternatives, modifications, and variations will be apparent to those skilled in the art.

  For example, in the above embodiment, the printing system 100 includes the master unit 110, the intermediate inversion device 120, the slave device 130, and the output inversion device 140. However, the present invention is not limited to this configuration, and a sheet feeding device, a post-processing device, and the like may be further added.

  In the above embodiment, the control unit 111 of the parent device 110 controls the parent device 110 and the intermediate inverting device 120, and the control unit 131 of the child device 130 controls the child device 130 and the output inverting device 140. Yes. However, the present invention is not limited to this, and the main subject of control can be provided in any device without being provided in the parent device 110 or the child device 130. For example, the intermediate reversing device 120 and the output reversing device 140 may be provided with a control unit similar to the parent device 110 so that each of the devices 110 to 140 can be controlled independently. Further, the master unit 110 may directly control the output inverting device 140.

  Moreover, in said embodiment, although the 1st-3rd conditions are mentioned as a predetermined condition by which a user can recognize the difference in color on a spread page, this invention is not limited to this. If there is a possibility that the user may recognize a difference in color on the spread page, another condition may be added or changed to another condition.

  In the above-described embodiment, printing is performed in the order of pages defined in advance in the print data, and the sheets are sequentially discharged onto the discharge tray 150. However, the present invention is not limited to this, and printing may be executed in the reverse order to the page order previously defined in the print data. In this case, in step S104 described above, the initial setting of the paper discharge surface setting information is set to “FaceDown”. Further, in step S110 described above, when the latest discharge surface setting information is “FaceDown” (step S110: YES), the control unit 111 advances the process to step S111. If the latest paper discharge surface setting information is “FaceUp” (step S110: NO), the process proceeds to step S113.

  In addition, the configuration of the printing system 100 described above is the main configuration in describing the features of the above-described embodiment, and is not limited to the above-described configuration. Further, the configuration of the general printing system 100 is not excluded.

  Further, each functional configuration of base unit 110 shown in FIG. 3 is classified according to main processing contents in order to facilitate understanding of each functional configuration. The present invention is not limited by the way of classification and names of the constituent elements. Each functional configuration can be classified into more components according to the processing content. Moreover, it can also classify | categorize so that one component may perform more processes.

  The processing of each functional configuration shown in FIG. 3 can also be realized by a dedicated hardware circuit. In this case, it may be executed by one hardware or a plurality of hardware.

  The program for operating the master unit 110 and the slave unit 130 may be provided by a computer-readable recording medium such as a USB memory, a flexible disk, a CD-ROM, or provided online via a network such as the Internet. May be. In this case, the program recorded on the computer-readable recording medium is usually transferred to and stored in a memory or storage. Further, this program may be provided as, for example, a single application software, or may be incorporated in the software of each apparatus as one function of the printing system 100.

100 printing system,
110 Master unit,
111 control unit,
112 communication unit,
113 Paper storage unit,
114 image forming unit,
115 fixing unit,
116 operation panel,
120 intermediate reversing device,
123 paper transport section,
124 reversing part,
125 switch part,
130 handset,
131 control unit,
132 communication unit,
134 Image forming unit,
135 fixing section,
140 output reversing device,
143 paper transport section,
144 Inversion part,
145 switch part,
150 paper exit tray,
200 PC,
310 extraction unit,
320 color taste determination unit,
330 Image formation controller,
340 Paper spacing setting unit.

Claims (8)

A series tandem printing system in which different image forming units form an image on a first side and a second side of a sheet to perform double-sided printing,
An extraction unit that extracts objects included in the print data to be printed;
In the case of creating a booklet by duplex printing on a plurality of sheets based on the print data, among the objects extracted by the extraction unit, the objects used for each page of the spread pages of the booklet are compared, A color determination unit that determines whether a predetermined condition that allows a difference in color between pages to be recognized is satisfied,
An image forming control unit that performs control to make the image forming unit that forms an image on each of the spread pages the same when the color determining unit determines that the predetermined condition is satisfied;
A printing system comprising: The color determination unit
When the same object is included in each page of the spread page, when an inverted object is included in each page of the spread page, and an approximate color is included in the center portion of the spread page The printing system according to claim 1, wherein the printing system determines that the predetermined condition is satisfied in at least one of the cases. A paper discharge control unit that selectively discharges either the first side or the second side of the paper after double-sided printing toward the upper surface;
The printing system according to claim 1, further comprising: a sheet interval setting unit that changes a sheet interval of sheets to be continuously fed in accordance with a sheet discharge result by the sheet discharge control unit. A paper discharge control unit that selectively discharges either the first surface or the second surface of the paper after double-sided printing toward the upper surface;
The image forming control unit controls an image of a page formed by each of different image forming units in series and a paper discharge surface, thereby making the image forming unit that forms an image on each of the spread pages the same. The printing system according to any one of claims 1 to 3. A printing method based on a serial tandem method in which different image forming units form images on the first side and the second side of a sheet to perform double-sided printing,
(A) extracting an object included in print data to be printed;
(B) When creating a booklet by duplex printing on a plurality of sheets based on the print data, among the objects extracted in the step (a), an object used for each page of the spread page of the booklet. A step of comparing to determine whether a predetermined condition for recognizing a color difference between the pages is satisfied;
(C) If it is determined in step (b) that the predetermined condition is satisfied, a step of performing control to make the image forming units that form an image on each of the spread pages the same;
A printing method comprising: In step (c),
When the same object is included in each page of the spread page, when an inverted object is included in each page of the spread page, and an approximate color is included in the center portion of the spread page The printing method according to claim 5, wherein it is determined that the predetermined condition is satisfied in at least one of the cases. (D) a step of selectively discharging either the first surface or the second surface of the paper after double-sided printing toward the upper surface;
The printing method according to claim 5, further comprising: (e) changing a gap between sheets to be continuously fed in accordance with a discharge result in step (d). (D) further comprising a step of selectively discharging either the first surface or the second surface of the paper after double-sided printing toward the upper surface;
In the step (c), the image forming unit that forms an image on each of the spread pages is made the same by controlling the image of the page formed by each of the different image forming units in series and the paper discharge surface. The printing method according to any one of claims 5 to 7.