Control device, image forming system, control method, and program

Abstract

To obtain a contraction amount or contraction coefficient in the conveyance direction of a recording medium by a fixation unit.SOLUTION: A control device 9 of an image formation system 10 having an image formation unit 12 for forming an image on a recording medium P formed of a continuous sheet or long sheet comprises an output unit 911 which obtains the width of the recording medium P on the downstream side in the conveyance direction of the recording medium P with respect to a fixation unit 124 of the image formation unit 12, and outputs a contraction amount or contraction coefficient in the conveyance direction of the recording medium P by the fixation unit 124 on the basis of the width of the recording medium P and contraction characteristic information of the recording medium P.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device, an image forming system, a control method, and a program.

Background Art

[0002] In an image forming apparatus, fixing of the formed image is performed by heating after image formation. At this time, since shrinkage may occur due to heating, a conventional image forming apparatus detects the leading edge and the trailing edge of the conveyed paper by sensors, obtains the elapsed time from the passage of the leading edge to the passage of the trailing edge, multiplies this by the conveyance speed to obtain the length in the conveyance direction of the paper, and acquires the amount of shrinkage of the paper (see, for example, Patent Document 1).

[0003] Further, a conventional image forming apparatus that forms an image on continuous paper such as continuous forms includes a first image forming unit that forms an image on the front surface of the continuous paper and a second image forming unit that forms an image on the back surface of the continuous paper, and sensor units are provided on the upstream side and the downstream side of the fixing unit of the first image forming unit, respectively. Each sensor unit has a mark sensor that detects detection marks formed at regular intervals on the continuous paper and an edge sensor that detects the edge positions at both ends in the width direction of the continuous paper. Then, the amount of shrinkage in the conveyance direction of the continuous paper is output from the elapsed time until two detection marks are sequentially detected by the mark sensor, and the amount of shrinkage in the width direction of the continuous paper is output from each edge position at both ends in the width direction by the edge sensor (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the image forming apparatus of Patent Document 1, when detecting the amount of shrinkage in the paper conveyance direction, since the leading edge and the trailing edge of the paper are detected by sensors, in the case of continuous paper such as continuous forms that are continuous in the conveyance direction, it is impossible to obtain detection of the leading edge or the trailing edge, and it has been difficult to detect the amount of shrinkage in the conveyance direction.

[0006] Also, in the image forming apparatus of Patent Document 2, when detecting the amount of shrinkage in the paper conveyance direction, two sensor units are required on the upstream side and the downstream side of the fixing unit, which may lead to an increase in the size of the apparatus and an increase in component costs.

[0007] On the other hand, in the case of a configuration in which the length of the continuous paper in the conveyance direction is detected from the elapsed time until two detection marks are sequentially detected by one mark sensor, there is a problem that the amount of shrinkage in the paper conveyance direction before and after the fixing unit cannot be correctly detected for the following reasons. For example, a case will be exemplified in which two detection marks are formed at an interval of 100 [mm], the conveyance speed of the fixing unit 101 is 500 [mm / s], and the elapsed time until the two detection marks are detected is detected. As shown in FIG. 20(A), when the fixing unit 101 is in a non-heated state and the continuous paper P does not shrink, the continuous paper P is also conveyed at a conveyance speed of 500 [mm / s] on the downstream side in the conveyance direction of the fixing unit 101. Therefore, the elapsed time until the two detection marks are detected is 100÷500 = 0.2 [s]. On the contrary, as shown in FIG. 20(B), on the premise that the continuous paper P shrinks by 1% due to the heating of the fixing unit 101, since the continuous paper P is constrained by the rollers of the fixing unit 101, on the downstream side in its conveyance direction, the conveyance speed decreases to 495 [mm / s]. On the other hand, the interval between the two detection marks shrinks to 99 [mm], but due to the decrease in the conveyance speed, the elapsed time until the two detection marks are detected is 99÷495 = 0.2 [s].

[0008] Thus, in the case of continuous paper or long paper, when attempting to detect the amount of shrinkage in the conveyance direction of the paper before and after fixing with a single sensor, even if shrinkage of the paper occurs in the conveyance direction, the elapsed time until two detection marks are detected becomes equal, and the occurrence of shrinkage cannot be correctly detected. In addition, in FIGS. 20(A) and 20(B), a configuration having a paper discharge roller 102 that performs driven rotation on the downstream side of the fixing unit 101 is illustrated, but the result is the same even when the paper discharge roller 102 is not provided.

[0009] An object of the present invention is to appropriately grasp the shrinkage state due to heating for a recording medium such as a continuous sheet or a long sheet.

Means for Solving the Problems

[0010] In order to solve the above problems, the invention according to claim 1 is a control device for an image forming system including an image forming unit that forms an image on a recording medium composed of a continuous sheet or a long sheet, obtaining the width of the recording medium on the downstream side in the conveyance direction of the recording medium from a fixing unit included in the image forming unit, and outputting a shrinkage amount or shrinkage rate in the conveyance direction of the recording medium by the fixing unit based on the width of the recording medium and the shrinkage characteristic information of the recording medium, characterized by comprising an output unit.

[0011] The invention according to claim 2 is the control device according to claim 1, wherein the shrinkage characteristic information of the recording medium includes information indicating the paper type.

[0012] The invention according to claim 3 is the control device according to claim 1 or claim 2, wherein the shrinkage characteristic information of the recording medium includes information indicating the grain direction of the paper.

[0013] The invention according to claim 4 is the control device according to claim 3, comprising a storage unit that stores information specifying a shrinkage rate ratio between the width direction and the conveyance direction of the recording medium for each of a plurality of the grain directions of the paper. The output unit outputs the shrinkage amount or shrinkage rate in consideration of information specifying the shrinkage rate ratio.

[0014] The invention according to claim 5 is a control device according to any one of claims 1 to 4, wherein the shrinkage characteristic information of the recording medium includes information indicating at least one of the moisture content or thickness of the paper.

[0015] The invention according to claim 6 is a control device according to any one of claims 1 to 5, wherein the shrinkage characteristic information of the recording medium includes information indicating at least one of the basis weight or stiffness of the paper.

[0016] The invention according to claim 7 is a control device according to any one of claims 1 to 6, wherein the shrinkage characteristic information of the recording medium includes fixing condition information.

[0017] The invention according to claim 8 is the control device according to claim 7, wherein the fixing condition information includes information indicating at least one of fixing temperature, fixing pressure, fixing speed, and fixing time.

[0018] The invention according to claim 9 is a control device according to any one of claims 1 to 8, wherein the shrinkage characteristic information of the recording medium includes the tension of the recording medium on the downstream side in the conveyance direction of the fixing unit.

[0019] The invention according to claim 10 is the control device according to claim 9, wherein the shrinkage characteristic information of the recording medium includes, as the tension of the recording medium, the tension of the recording medium between the fixing unit and a conveyance roller of the recording medium provided on the downstream side in the conveyance direction of the fixing unit.

[0020] The invention according to claim 11 is the control device according to claim 10, The tension of the recording medium is characterized by being based on a conveyance speed difference or a torque difference between the fixing unit and the conveyance roller.

[0021] The invention according to claim 12 is a control device according to any one of claims 1 to 11, characterized by including a correction unit that corrects the size of an image formed by the image forming unit based on the amount of shrinkage or the shrinkage rate output by the output unit.

[0022] The invention according to claim 13 is a control device according to any one of claims 1 to 12, characterized by including a determination unit that performs a pass / fail determination on the amount of shrinkage or the shrinkage rate output by the output unit.

[0023] The invention according to claim 14 is an image forming system, characterized by including a control device according to any one of claims 1 to 13.

[0024] The invention according to claim 15 is the image forming system according to claim 14, characterized by including a detection unit that detects the width of the recording medium on the downstream side in the conveyance direction of the recording medium from the fixing unit of the image forming unit, wherein the detection unit is a sensor having a plurality of light receiving elements arranged along the width direction of the recording medium.

[0025] The invention according to claim 16 is the image forming system according to claim 15, characterized in that the sensor is capable of reading an image formed on the recording medium.

[0026] The invention according to claim 17 is an image forming system according to any one of claims 14 to 16, characterized by including a post-processing unit that performs post-processing on the recording medium on which an image is formed, wherein the control device includes a post-processing control unit that corrects the timing of post-processing executed by the post-processing unit in reflection of the amount of shrinkage or the shrinkage rate.

[0027] The invention according to claim 18 is the image forming system according to claim 17, wherein the post-processing unit executes, as the post-processing, cutting or creasing processing along the width direction of the recording medium.

[0028] The invention according to claim 19 is a control method for an image forming system including an image forming unit that forms an image on a recording medium composed of a continuous sheet or a long sheet, obtaining the width of the recording medium on the downstream side in the conveyance direction of the recording medium from a fixing unit included in the image forming unit, and outputting a shrinkage amount or shrinkage rate in the conveyance direction of the recording medium by the fixing unit based on the width of the recording medium and the shrinkage characteristic information of the recording medium.

[0029] The invention according to claim 20 is a program, causing a computer of an image forming system including an image forming unit that forms an image on a recording medium composed of a continuous sheet or a long sheet to obtain the width of the recording medium on the downstream side in the conveyance direction of the recording medium from a fixing unit included in the image forming unit, and output a shrinkage amount or shrinkage rate in the conveyance direction of the recording medium by the fixing unit based on the width of the recording medium and the shrinkage characteristic information of the recording medium, as an output unit characterized by functioning.

Advantages of the Invention

[0030] According to the present invention, for a continuous sheet, the shrinkage rate due to heating can be appropriately obtained.

Brief Description of the Drawings

[0031]

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[0032] The image forming system according to the present embodiment will be described in detail with reference to the drawings. Note that the image forming system according to the present embodiment is an example of the present invention and is not limited thereto.

[0033] [Overall Configuration Example of Image Forming System] An overall configuration example of the image forming system 10 will be described with reference to the drawings. FIG. 1 is a schematic diagram of the image forming system 10, and FIG. 2 is a block diagram showing the control system of the image forming system 10. The image forming system 10 is for forming an image on a recording medium made of a continuous sheet of continuous paper P. As shown in FIGS. 1 and 2, the image forming system 10 includes, in order from the upstream of the image conveyance path, a paper supply device 5, an image forming device 1, an image reading device 3, a post-processing device 7 as a post-processing unit, and a paper recovery device 6 as a winding unit. The image forming system 10 also includes a first control unit 8 that controls the paper supply device 5 and the post-processing device 7, and a second control unit 9 as a control device that comprehensively controls the image forming device 1, the image reading device 3, and the post-processing device 7. These control units 8 and 9 are communicably connected through their communication units 85 and 95.

[0034] Here, the continuous paper P used as a recording medium in the image forming system 10 indicates a long continuous recording paper from the leading end fed out from the roll to the trailing end on the deepest part side of the roll. Note that the continuous paper P is conveyed along its longitudinal direction. In the following description, the conveyance direction (longitudinal direction) of the continuous paper P may be referred to as the FD direction, and the direction parallel to the paper surface of the continuous paper P and perpendicular to its longitudinal direction (width direction) may be referred to as the CD direction.

[0035] [Paper Feeding Device] The paper feeding device 5 supports the roll around which the continuous paper P before image formation is wound, and includes a motor as a drive source (not shown) that rotationally drives the roll in the feeding direction. The paper feeding device 5 supplies the fed continuous paper P to the paper feed port 131 of the image forming apparatus 1. Also, the paper feeding device 5 is controlled by the first control unit 8 so that the tension of the continuous paper P passing from the roll to the image forming apparatus 1 by the motor of the drive source becomes constant.

[0036] [Paper Recovery Device] The paper recovery device 6 is a winding means for winding and recovering the continuous paper P on which an image has been formed and the image reading by the image reading device 3 has been completed. Since the paper recovery device 6 forms a roll while winding the continuous paper P, it includes a motor as a drive source (not shown) that rotationally drives the roll. The paper recovery device 6 is disposed on the downstream side in the conveyance direction of the continuous paper P with respect to the post-processing device 7, and recovers the continuous paper P that has passed through the post-processing device 7. Also, the paper recovery device 6 is controlled by the first control unit 8 so that the tension of the continuous paper P wound from the image reading device 3 side by the motor of the drive source becomes constant.

[0037] [Image Forming Apparatus] The image forming apparatus 1 is, for example, an electrophotographic image forming apparatus such as a copying machine. As shown in FIG. 1, the image forming apparatus 1 is also referred to as a so-called tandem type color image forming apparatus, and is arranged such that a single intermediate transfer belt extends along a predetermined direction (the vertical direction in this embodiment), and a plurality of photosensitive drums facing the intermediate transfer belt are arranged in the belt extending direction, so that a full-color image can be formed on the intermediate transfer belt.

[0038] As shown in FIGS. 1 and 2, the image forming apparatus 1 includes, for example, a document reading unit 11, an image forming unit 12, a first conveyance path 13, and an operation display unit 14. Each part of the image forming apparatus 1 is interconnected via a bus (not shown).

[0039] [Image forming apparatus: Document reading unit] The document reading unit 11 includes an automatic document feeder (ADF), a platen glass, an optical system, etc., and reads a document placed on the ADF or the platen glass by the optical system to obtain image data. Note that the image forming apparatus 1 can also acquire image data by communication not only from the document reading unit 11 but also from an external host device (e.g., a personal computer (PC)).

[0040] [Image forming apparatus: Image forming unit] Based on the acquired image data, the image forming unit 12 forms an image with toner on the continuous paper P. The image forming unit 12 includes, for example, a cyan (C) image forming unit 12C that forms a cyan image, a magenta (M) image forming unit 12M that forms a magenta image, a yellow (Y) image forming unit 12Y that forms a yellow image, and a black (K) image forming unit 12K that forms a black image, an intermediate transfer belt 121, an intermediate transfer roller 122, and a fixing unit 124. Regarding the image forming units 12C to 12K, for example, a configuration including only one of the image forming units 12C to 12K or a configuration including a plurality of any one type of the image forming units 12C to 12K may be employed.

[0041] Each image forming unit 12C to 12K includes a photosensitive drum on which a toner image is formed, a charging unit that charges the photosensitive drum to a predetermined potential, an exposure unit that exposes the charged image carrier to form an electrostatic latent image according to image data, a developing unit that develops the electrostatic latent image to form a toner image, and a drum cleaner that removes residual toner from the photosensitive drum.

[0042] The images formed on each photosensitive drum are sequentially primary-transferred to a predetermined position on an intermediate transfer belt 121 which is a belt-shaped intermediate transfer member. The images composed of respective colors transferred onto the intermediate transfer belt 121 are secondary-transferred between the intermediate transfer belt 121 and an intermediate transfer roller 122 to a continuous paper P conveyed through a first conveyance path 13. The conveyance of the intermediate transfer belt 121 and the rotation of the intermediate transfer roller 122 are driven by a transfer motor 123 (see FIG. 2) as a drive source. The transfer motor 123 is composed of, for example, a DC motor or an AC motor suitable for speed control and torque control. Here, the case where the transfer motor 123 is a DC brushless motor is exemplified. Also, an encoder 123a for detecting the rotation amount thereof is provided in parallel with the transfer motor 123.

[0043] A fixing unit 124 is provided on the downstream side of the intermediate transfer belt 121. The fixing unit 124 includes a fixing roller 125 and a pressure roller 126 that fix the secondary-transferred toner image to the continuous paper P, and a fixing motor 127 (see FIG. 2) that serves as a rotation drive source for these. The fixing motor 127 is composed of, for example, a DC motor or an AC motor. Here, the case where the fixing motor 127 is a DC brushless motor is exemplified. Also, an encoder 127a for detecting the rotation amount thereof is provided in parallel with the fixing motor 127.

[0044] The fixing unit 124 performs a fixing process of conveying the continuous paper P and fixing the toner image by means of a pair of pressure-bonded fixing rollers 125 and a pressure roller 126. A heater is provided inside the fixing roller 125. By this heater, the continuous paper P passing through the fixing nip between the fixing roller 125 and the pressure roller 126 is heated to melt the toner image and fix it on the continuous paper P.

[0045] [Image forming apparatus: First conveyance path] As shown in FIG. 1, the first conveyance path 13 is a conveyance path of the continuous paper P from a paper feed port 131 provided at one end side (the right side in FIG. 1) in the conveyance direction of the continuous paper P of the image forming apparatus 1 to a paper discharge port 132 provided at the other end side (the left side in FIG. 1) in the conveyance direction of the continuous paper P. On the first conveyance path 13, a media sensor 15 for detecting the physical property value of the continuous paper P, the intermediate transfer belt 121 and the intermediate transfer roller 122 of the above-described image forming unit 12, and the fixing unit 124 are arranged in order from the upstream side to the downstream side in the conveyance direction. A guide roller for guiding the conveyance of the continuous paper P may be provided on the path of the first conveyance path 13.

[0046] In the first conveyance path 13, the continuous paper P is conveyed by the intermediate transfer roller 122, the transfer motor 123, the fixing roller 125 of the fixing unit 124, the pressure roller 126, and the fixing motor 127 of the image forming unit 12. However, separately from these, a conveyance roller may be provided on the first conveyance path 13.

[0047] [Image forming apparatus: Media sensor] The media sensor 15 detects the physical property value of the continuous paper P as shrinkage characteristic information on the upstream side in the conveyance direction of the intermediate transfer belt 121. The media sensor 15 is composed of one or a plurality of sensors for measuring the paper type, grain direction, thickness, moisture content, stiffness, etc. as the physical property value of the continuous paper P to be fed, and outputs the measurement result to the second control unit 9.

[0048] The media sensor 15 is, for example, an optical sensor having a light emitting unit that irradiates light onto the continuous paper P and a light receiving unit that receives the reflected light reflected by the continuous paper P, and can obtain the basis weight (weight per unit area of a single sheet), paper type, and grain direction of the continuous paper P from the voltage value output by the light receiving unit. Further, the media sensor 15 includes a displacement sensor that detects the thickness of the continuous paper P, a capacitance sensor that detects the water content of the continuous paper P, and the like. Furthermore, the media sensor 15 has an acceleration sensor provided on a contact body such as an elastically supported roller that contacts the conveyed continuous paper P, and can detect the stiffness of the continuous paper P from the detected acceleration.

[0049] [Image forming apparatus: Operation display unit] The operation display unit 14 includes, for example, an operation unit 141 and a display unit 142. The operation unit 141 is composed of a plurality of operation buttons and receives the user's operations. The display unit 142 is configured to include an LCD (Liquid Crystal Display), an organic EL display, or the like. Further, a pressure-sensitive touch panel in which transparent electrodes are arranged in a grid pattern is provided on the display. The display unit 142 presents various screens such as a guidance screen to the user, displays an image of an operation button for touch operation, and receives the user's touch operation.

[0050] [Image reading device] The image reading device 3 includes a reading unit 31 as an image reading means, a cooling means 34, and a second conveyance path 35.

[0051] As shown in FIG. 1, the second conveyance path 35 guides the conveyance of the continuous paper P from a paper feed port 351 provided on one end side (the right side in FIG. 1) in the conveyance direction of the continuous paper P of the image reading device 3 to a paper discharge port 352 provided on the other end side (the left side in FIG. 1) in the conveyance direction of the continuous paper P. The paper feed port 351 is connected to the paper discharge port 132 of the image forming device 1. The paper discharge port 352 is connected to the post-processing device 7 and further to the paper collection device 6. The continuous paper P after image reading is carried out, and post-processing by the post-processing device 7 is performed or it is collected by the paper collection device 6. On the second conveyance path 35, the cooling means 34 and the reading unit 31 are arranged in order from the upstream side to the downstream side in the conveyance direction.

[0052] The conveyance of the continuous paper P in the second conveyance path 35 is performed by the drive source of the conveyance roller 76 of the post-processing device 7 on the downstream side in the conveyance direction of the image reading apparatus 3 or the winding of the paper collection device 6. A plurality of guide rollers 331 are provided on the second conveyance path 35, and these consist of roller pairs that guide the conveyance by sandwiching the continuous paper P from both sides.

[0053] The cooling means 34 cools the continuous paper P heated by the heater of the fixing unit 124 of the image forming apparatus 1. The cooling means 34 cools the continuous paper P conveyed in the second conveyance path 35 by blowing air. Note that the cooling means 34 may be configured to blow air cooled using a cooling element such as a Peltier element.

[0054] The reading unit 31 has a reading scanner 311 and a colorimeter 312, and the reading scanner 311 is arranged on the upstream side in the conveyance direction of the colorimeter 312. Also, the reading scanner 311 is constituted by a line sensor having a plurality of light receiving elements arranged in the CD direction such as a CCD (Charge-Coupled Device) sensor. The colorimeter 312 is constituted by a spectrophotometer.

[0055] The reading scanner 311 and the colorimeter 312 can read an image printed on the upper surface of the continuous paper P conveyed along the second conveyance path 35. Further, the reading scanner 311 is configured to have light receiving elements over a wider range than the width in the CD direction of the continuous paper P of the maximum size assumed to be used, and can detect the width in the CD direction of the conveyed continuous paper P. That is, the reading scanner 311 also functions as a detection unit that detects the width of the continuous paper P which is a recording medium. Then, the reading data of the formed image of the continuous paper P read by the reading scanner 311 and the colorimeter 312 is output to the second control unit 9. Based on the reading data, the second control unit 9 determines, for example, the quality and position deviation of the formed image, and also performs a comparison process between the reading data and the image data that is the source of the formed image.

[0056] [Post-processing device] The post-processing device 7 includes a conveyance path connected to the paper discharge port 352 of the image reading device 3, and performs post-processing on the continuous paper P carried into the conveyance path from the paper discharge port 352 as necessary. Examples of the post-processing include slitter processing, dob slitter processing, CD cutting processing, crease processing (upper convex or lower convex), FD / CD sewing processing, etc. The above post-processing is not essential and is executed, for example, when an execution instruction is input from the operation display unit 14 or the like.

[0057] As shown in FIG. 1, the post-processing device 7 includes a plurality of post-processing modules 71 to 74 arranged side by side along the conveyance path, a pair of conveyance rollers 76 that convey the continuous paper P, and a guide mechanism 75 that can selectively send the continuous paper P to the conveyance path leading to the paper collection device 6 and a branch path branched from the conveyance path on the downstream side in the conveyance direction of the conveyance rollers 76, and a paper tray 78 provided on the downstream side in the conveyance direction of the branch path.

[0058] For example, a slitter is installed as the uppermost post-processing module 71, a bottom convex creaser for performing a creasing process of attaching downward convex ribs to the continuous paper P is installed as the post-processing module 72, a dob slitter for cutting the paper at the center in the CD direction (paper width direction) is installed as the post-processing module 73, and a CD cutter for cutting the paper in the CD direction (paper width direction) is installed in the post-processing module 74. Note that the number of post-processing modules can be increased or decreased, and the types of post-processing are not limited to those described above.

[0059] A pair of conveying rollers 76 are rotationally driven by a conveying motor 77 (see FIG. 2) serving as a drive source. The conveying motor 77 is provided with an encoder 77a for detecting its rotational speed, and speed control is performed by the second control unit 9.

[0060] The guide mechanism 75 includes a guide member capable of moving forward and backward. When moving forward, the guide member enters the conveying path toward the paper collection device 6 and guides the continuous paper P to the branch path side. When moving backward, the guide member moves away from the conveying path toward the paper collection device 6 and does not impede the conveyance of the continuous paper P to the paper collection device 6 side. The guide mechanism 75 is controlled by the second control unit 9, operates in conjunction when the continuous paper P is cut into single sheets by the aforementioned CD cutter, and guides the cut single sheets to the paper tray 78 side.

[0061] [Control Unit] As shown in FIG. 2, the first and second control units 8, 9 each include a CPU (Central Processing Unit) 81, 91, a ROM (Read Only Memory) 82, 92, a RAM (Random Access Memory) 83, 93, and an HDD (Hard Disk Drive) 84, 94 as a computer.

[0062] The CPUs 81, 91 read and execute software program codes for performing various controls and various processes from the ROMs 82, 92. The ROMs 82 and 92 are used as an example of non-volatile memories and store programs, data, etc. necessary for the operation of the CPUs 81 and 91. The RAMs 83 and 93 are used as an example of volatile memories and temporarily store variables, parameters, etc. generated during the arithmetic processing necessary for each process performed by the CPUs 81 and 91.

[0063] The HDDs 84 and 94 are an example of non-volatile storage, and the HDDs 84 and 94 store programs for the CPU 81 and 91 to control each part, an OS (Operating System), programs such as a controller, and data. Note that the non-volatile storage is not limited to HDDs, and other non-volatile memories may be used. Also, the recording medium storing the programs executed by each control unit 8 and 9 is not limited to the ROMs 82 and 92 and HDDs 84 and 94, and may be, for example, a recording medium such as an SSD (Solid State Drive), a CD-ROM, or a DVD-ROM.

[0064] The first control unit 8 is connected to the paper supply device 5 and the paper collection device 6, performs various processes involving operation control and information communication for these, and executes the supply and collection of the continuous paper P. Specifically, the first control unit 8 performs torque control on a motor (not shown) that is a drive source of the paper supply device 5 so that the tension of the continuous paper P passing from the paper supply device 5 to the image forming device 1 becomes constant. Also, the first control unit 8 performs torque control on a motor (not shown) that is a drive source of the paper collection device 6 so that the tension of the continuous paper P passing from the image reading device 3 to the paper collection device 6 becomes constant.

[0065] The second control unit 9 is connected to the original reading unit 11, the media sensor 15, the image forming unit 12, the operation display unit 14 of the image forming device 1, the cooling means 34, the reading unit 31 of the image reading device 3, and the post-processing device 7, performs various processes involving operation control and information communication for these, and executes various processes on the continuous paper P.

[0066] Furthermore, the CPU 91 of the second control unit 9 includes a shrinkage amount output unit 911 as an output unit, a correction unit 912, a post-processing control unit 913, and a determination unit 914. These shrinkage amount output unit 911, correction unit 912, post-processing control unit 913, and determination unit 914 are all exemplified as functional configurations realized by the CPU 91 executing a predetermined program. However, it is not limited to the functional configuration, and each may be configured by hardware consisting of a dedicated processor or circuit.

[0067] The shrinkage amount output unit 911 outputs the shrinkage rate in the FD direction that occurs in the continuous paper P when heat fixing is performed by the fixing unit 124. The correction unit 912 corrects the size of the image formed by the image forming unit 12 in consideration of the shrinkage rate in the FD direction of the continuous paper P output by the shrinkage amount output unit 911. The post-processing control unit 913 performs operation control of the post-processing executed by the post-processing device 7 in consideration of the shrinkage rate in the FD direction of the continuous paper P output by the shrinkage amount output unit 911. The determination unit 914 determines the suitability of the shrinkage rate in the FD direction of the continuous paper P output by the shrinkage amount output unit 911.

[0068] [Regarding the output of shrinkage characteristic information of the recording medium] The continuous paper P conveyed during image formation is post-processed according to the settings, and while being conveyed from the paper supply device 5 to the paper collection device 6, the physical property values of the continuous paper P are detected by the media sensor 15. Also, image data is acquired by reading by the original reading unit 11 or communication from the outside, and a toner image based on the image data is transferred by the image forming unit 12. Then, the toner image transferred to the continuous paper P is fixed by heating in the fixing unit 124 on the downstream side thereof. The continuous paper P on which the toner image is fixed and the image is formed is cooled by the cooling means 34 of the image reading device 3, and reading is performed by the reading scanner 311 and the colorimeter 312. Then, the continuous paper P on which image formation has been performed is post-processed according to the settings, wound up by the paper collection device 6, and image formation is terminated. In addition, when post-cutting along the CD direction is performed as post-processing by the post-processing device 7, the continuous paper P is not collected by the paper collection device 6, but is cut into single sheets and conveyed to the paper tray 78.

[0069] In the image forming system 10, during the process of executing various processes on the continuous paper P in the above order, shrinkage may occur in the continuous paper P due to heat fixing by the fixing unit 124 of the image forming apparatus 1. And in the case of the long continuous paper P, a decrease in the conveyance speed may occur on the downstream side in the conveyance direction of the fixing unit 124 according to the amount of shrinkage. For this reason, in the conventional method, that is, it may be difficult to output the amount of shrinkage in the conveyance direction generated in the continuous paper P from the time interval at which two marks formed at a fixed interval between the upstream and the downstream are sequentially detected (see FIGS. 20(A) and 20(B) already shown).

[0070] Therefore, the second control unit 9 of the image forming system 10 enables the shrinkage amount output unit 911 to output the amount of shrinkage or the shrinkage rate in the conveyance direction (FD direction) of the continuous paper P by the fixing unit 124 based on the shrinkage characteristic information of the continuous paper P and the width of the continuous paper P in the CD direction detected by the reading scanner 311. Here, the case of outputting the shrinkage rate in the FD direction is illustrated. Hereinafter, the shrinkage amount output unit 911 will be described in detail.

[0071] FIG. 3 is an explanatory diagram showing the flow of processing for outputting shrinkage characteristic information by the shrinkage amount output unit 911. The "width of the continuous paper P" required for the shrinkage amount output unit 911 to output the shrinkage rate in the FD direction of the continuous paper P is the width in the CD direction of the continuous paper P after heat fixing that has passed through the fixing unit 124 (hereinafter simply referred to as the "width of the continuous paper P"), and can be detected by the reading scanner 311 of the reading unit 31 of the image reading apparatus 3.

[0072] The width of the continuous paper P before heat fixing by the fixing unit 124 is a fixed value, and the shrinkage amount output unit 911 can obtain the shrinkage rate in the CD direction of the continuous paper P by comparing it with the width of the continuous paper P detected by the reading scanner 311. Furthermore, the shrinkage rate ratio, which is the ratio of the shrinkage rate in the FD direction to the shrinkage rate in the CD direction of the continuous paper P, has a correlation with various parameters belonging to the shrinkage characteristic information. Therefore, the shrinkage amount output unit 911 obtains various parameters belonging to the shrinkage characteristic information, specifies the shrinkage rate ratio therefrom, and multiplies the shrinkage rate ratio by the shrinkage rate in the CD direction obtained by reading the width of the continuous paper P to output the shrinkage rate in the FD direction.

[0073] Examples of the shrinkage characteristic information of the continuous paper P include physical property values such as the grain direction, moisture content, and thickness of the continuous paper P. These can be detected by the media sensor 15. The grain direction is the direction of the paper fibers. As shown in FIG. 4, the paper in which the fibers flow along the longitudinal direction of the continuous paper P (coinciding with the FD direction) is called T grain, and the paper in which the fibers flow along the short side direction of the continuous paper P (coinciding with the CD direction) is called Y grain.

[0074] Each of FIGS. 5(A) to 5(C) is a relational diagram showing the relationship between the thickness, grain direction, and moisture content of the paper as shrinkage characteristic information and the shrinkage rate of the paper. As shown in FIG. 5(A), the continuous paper P tends to have a decreasing shrinkage rate with an increase in thickness. FIG. 5(B) shows the shrinkage rate in the longitudinal direction (FD direction) of the continuous paper P. As shown, the shrinkage rate in the FD direction of the Y grain paper is higher than that of the T grain paper. Conversely, this also shows that the shrinkage rate in the CD direction of the T grain paper is higher than that of the Y grain paper. As shown in FIG. 5(C), the continuous paper P tends to have an increasing shrinkage rate with an increase in moisture content.

[0075] The second control unit 9 holds in the ROM 92 or HDD 94 as a storage unit the data of the correspondence table between the thickness and grain direction and the shrinkage rate ratio considering the above characteristics and the data of the correspondence table between the moisture content and the change rate α of the shrinkage rate based on the moisture content. FIG. 6 is an explanatory diagram showing the content of the correspondence table between the thickness and grain direction and the shrinkage rate ratio. In this table, for the case where the continuous paper P is the T-th sheet, the shrinkage rate ratio in the FD direction when the shrinkage rate in the CD direction is set to 1, and for the case where the continuous paper P is the Y-th sheet, the shrinkage rate ratio in the FD direction when the shrinkage rate in the CD direction is set to 1 are determined for each of the multiple numerical thicknesses of the continuous paper P. Note that although the shrinkage rate ratio of the continuous paper P varies corresponding to the moisture content, all the values of the shrinkage rate ratio defined in the table of FIG. 6 indicate the numerical values when the moisture content is fixed at a reference value (for example, 7 [%]). When the sheet direction and thickness of the continuous paper P are acquired from the media sensor 15, the shrinkage amount output unit 911 can specify the shrinkage rate ratio by referring to the table of FIG. 6 above.

[0076] FIG. 7 is an explanatory diagram showing the content of a correspondence table between the moisture content and the change rate α of the shrinkage rate based on the moisture content. As described above, when the moisture content varies, the shrinkage rate of the continuous paper P varies. The table of FIG. 7 determines the change rate α of the shrinkage rate in the FD direction of the continuous paper P with respect to the shrinkage rate at the moisture content of the reference value (for example, 7 [%]) for each of the multiple numerical moisture contents based on the curve of FIG. 5(C). When the moisture content of the continuous paper P is acquired from the media sensor 15, the shrinkage amount output unit 911 obtains the change rate α by referring to the table of FIG. 7 above, and multiplies it by the shrinkage rate in the FD direction of the continuous paper P based on the shrinkage rate ratio specified from the table of FIG. 6 to perform correction according to the moisture content.

[0077] [Operation Example (1)] The operation example (1) in the above image forming system 10 will be described based on the flowcharts of FIGS. 3 and 8. In this operation example (1), the CPU 91 of the aforementioned second control unit 9 mainly executes overall operation control while cooperating with the CPU 81 of the first control unit 8. The CPU 91 executes the following operation control based on the control program stored in the ROM 92.

[0078] First, the CPU 91 starts the conveyance of the continuous paper P without performing image formation (step S1). That is, the CPU 91 requests the CPU 81 of the first control unit 8 to perform torque control so that the tension of the continuous paper P carried into the image forming apparatus 1 from the paper supply apparatus 5 and the tension of the continuous paper P discharged from the post-processing apparatus 7 to the paper collection apparatus 6 are the same target torque as during image formation, and to convey the continuous paper P. Furthermore, the CPU 91 executes operation control to convey the continuous paper P by performing speed control on the transfer motor 123 and the fixing motor 127 of the image forming apparatus 1 and the conveyance motor 77 of the post-processing apparatus 7 at the same target speed as during image formation. At this time, the CPU 91 controls so as to perform heat fixing by the fixing unit 124 under the same conditions as during image formation (fixing step), although image formation is not performed on the continuous paper P.

[0079] Then, the CPU 91 detects physical property values (paper thickness, grain direction, moisture content) of the conveyed continuous paper P by the media sensor 15 (step S3: characteristic acquisition step [arrow (a) in FIG. 3]). Furthermore, the CPU 91 detects the width in the CD direction of the continuous paper P that has undergone heat fixing by passing through the fixing unit 124 and the cooling means 34 by the reading scanner 311 of the image reading apparatus 3 (step S5: width detection step [arrow (b) in FIG. 3]).

[0080] Then, the shrinkage amount output unit 911 calculates the shrinkage rate (designated as Cr) in the CD direction due to heat fixing by the fixing unit 124 based on the width in the CD direction (designated as Cw’) of the continuous paper P detected by the reading scanner 311 and the width in the CD direction (designated as Cw) of the initial continuous paper P which is a known value. For example, the shrinkage rate Cr is calculated as (Cw - Cw’) / Cw. Furthermore, the shrinkage amount output unit 911 specifies the shrinkage rate ratio (designated as Sr) in the FD direction with respect to the CD direction by referring to the table in FIG. 6 based on the paper thickness and grain direction of the continuous paper P detected by the media sensor 15 (step S7).

[0081] Furthermore, the shrinkage amount output unit 911 calculates the shrinkage rate Fr in the FD direction from the shrinkage rate Cr in the CD direction and the shrinkage rate ratio Sr that have already been obtained. For example, the shrinkage rate Fr is calculated as Sr·Cr. Then, the shrinkage amount output unit 911 specifies the change rate α of the shrinkage rate with reference to the table in FIG. 7 from the moisture content of the continuous paper P detected by the media sensor 15, multiplies the change rate α by the shrinkage rate Fr in the FD direction for correction, and outputs the corrected shrinkage rate αFr in the FD direction considering the moisture content (step S9: shrinkage amount output step).

[0082] Here, the correction unit 912 corrects the image data to be formed by the image forming unit 12 based on the shrinkage rate αFr in the FD direction on the downstream side in the conveyance direction from the fixing unit 124 of the continuous paper P output by the shrinkage amount output unit 911 and the shrinkage rate Cr in the CD direction described above [arrow (c) in FIG. 3]. For example, the correction unit 912 performs correction to expand each shrinkage rate in the CD direction and the FD direction on the image data of the original image to be formed, and executes control of the image forming unit 12 to perform image formation based on the corrected image (step S11). Then, the process ends.

[0083] As described above, in the image forming system 10, the continuous paper P shrinks due to heat fixing by the fixing unit 124, but the formed image on the continuous paper P is suppressed from being affected by shrinkage, and image formation can be performed in the planned size. Thereafter, when repeatedly performing a plurality of image formations on the continuous paper P, correction can be performed using the shrinkage rate αFr in the FD direction and the shrinkage rate Cr in the CD direction output by the processing up to steps S1 to S9 above, and it is not necessary to output the shrinkage rate αFr in the FD direction and the shrinkage rate Cr in the CD direction every time.

[0084] [Operation Example (2)] The shrinkage characteristic information of the continuous paper P for the shrinkage amount output unit 911 to output the shrinkage rate in the FD direction of the continuous paper P may include the fixing condition information of the fixing unit 124. By including at least one of the fixing temperature, fixing pressure, fixing speed, and fixing time, which are the fixing condition information of the fixing unit 124, in the shrinkage characteristic information, the shrinkage rate in the FD direction of the continuous paper P can be output more appropriately. The fixing temperature, fixing pressure, fixing speed, and fixing time of the fixing unit 124 are individually determined according to the paper physical properties detected by the media sensor 15. Here, an example is given of the case where the fixing temperature, fixing pressure, and fixing speed of the fixing unit 124 are used as shrinkage characteristic information to correct the shrinkage rate of the continuous paper P in the FD direction.

[0085] The fixing unit 124 can control the fixing temperature by adjusting the heating amount of the heater, and the fixing temperature can be detected by a temperature sensor (not shown) provided in the fixing unit 124. Also, the fixing unit 124 is provided with an actuator (not shown) that adjusts the pressing force between the fixing roller 125 and the pressure roller 126, and the fixing pressure can be arbitrarily controlled. Furthermore, the fixing unit 124 can control the fixing speed by arbitrarily adjusting the rotation speed of the fixing motor 127. Also, the fixing time can be arbitrarily controlled from the width of the fixing nip between the fixing roller 125 and the pressure roller 126 in the conveyance direction and the rotation speed of the fixing motor 127.

[0086] When the second control unit 9 detects the paper type, grain direction, thickness, moisture content, etc. by the media sensor 15, it has table data in the ROM 92 or HDD 94 that determines the target fixing temperature, fixing pressure, and fixing speed of the fixing unit 124 using these as parameters. And the shrinkage amount output unit 911 can acquire the fixing temperature T of the fixing unit 124 from the temperature sensor provided in the fixing unit 124, and can acquire the fixing pressure P and the fixing speed V of the fixing unit 124 determined by the above table data.

[0087] The fixing temperature T by the heater in the fixing roller 125 of the fixing unit 124 shown in Fig. 9(A) has a tendency that the higher the fixing temperature T is, the higher the shrinkage rate of the continuous paper P becomes, as shown in the diagram of Fig. 9(B). Also, the fixing pressure P by the fixing roller 125 and the pressure roller 126 of the fixing unit 124 shown in Fig. 10(A) has a tendency that the higher the fixing pressure P is, the higher the shrinkage rate of the continuous paper P becomes, as shown in the diagram of Fig. 10(B). Further, as shown in the diagram of FIG. 11(B), the fixing speed V of the fixing roller 125 and the pressure roller 126 of the fixing unit 124 shown in FIG. 11(A) has a tendency that the shrinkage rate of the continuous paper P decreases as the fixing speed V increases.

[0088] Then, the second control unit 9 holds in the ROM 92 or the HDD 94 the data of the correspondence table of the change rate β of the shrinkage rate based on the fixing temperature T created based on the above tendency, the data of the correspondence table of the change rate γ of the shrinkage rate based on the fixing pressure P, and the data of the correspondence table of the change rate δ of the shrinkage rate based on the fixing speed V.

[0089] FIG. 12(A) is an explanatory diagram showing the content of the correspondence table of the change rate β of the shrinkage rate based on the fixing temperature T and the fixing temperature T. The table in FIG. 12(A) defines the change rate β of the shrinkage rate in the FD direction of the continuous paper P with respect to the shrinkage rate at the reference fixing temperature T for each of a plurality of numerical fixing temperatures T. The reference value of the fixing temperature T is set to 170 [°C]. FIG. 12(B) is an explanatory diagram showing the content of the correspondence table of the change rate γ of the shrinkage rate based on the fixing pressure P and the fixing pressure P. The table in FIG. 12(B) defines the change rate γ of the shrinkage rate in the FD direction of the continuous paper P with respect to the shrinkage rate at the reference fixing pressure P for each of a plurality of numerical fixing pressures P. The reference value of the fixing pressure P is set to 100 [kPa]. FIG. 12(C) is an explanatory diagram showing the content of the correspondence table of the change rate δ of the shrinkage rate based on the fixing speed V and the fixing speed V. The table in FIG. 12(C) defines the change rate δ of the shrinkage rate in the FD direction of the continuous paper P with respect to the shrinkage rate at the reference fixing speed V for each of a plurality of numerical fixing speeds V. The reference value of the fixing speed V is set to 400 [mm / s].

[0090] When the shrinkage amount output unit 911 acquires the fixing temperature T, the fixing pressure P, and the fixing speed V of the fixing unit 124, it obtains the change rates β, γ, δ by referring to the tables in FIGS. 12(A) to 12(C) above, and multiplies these by the shrinkage rate αFr in the FD direction of the continuous paper P based on the shrinkage rate ratio specified from the physical property values (paper thickness, grain direction, moisture content) of the continuous paper P described above, thereby performing correction according to the fixing condition information (fixing temperature, fixing pressure, fixing speed). Note that since the fixing time of the fixing unit 124 is in a relative relationship with the fixing speed, it is only necessary to correct either the fixing time or the fixing speed.

[0091] An operation example (2) in the above image forming system 10 will be described based on the flowcharts of FIGS. 3 and 13. In this operation example (2) as well, the CPU 91 of the second control unit 9 mainly executes overall operation control based on a control program.

[0092] The CPU 91 starts the conveyance of the continuous paper P through the first control unit 8 in the same manner as in the case of operation example (1) (step S21). However, the heating of the continuous paper P by the fixing unit 124 does not start until the fixing conditions described later are determined.

[0093] Then, the CPU 91 detects the physical property values (paper thickness, grain direction, moisture content) of the conveyed continuous paper P by the media sensor 15 (step S23: characteristic acquisition step [arrow (a) in FIG. 3]). Furthermore, the CPU 91 determines the fixing conditions (fixing temperature, fixing pressure, fixing speed) based on the physical property values of the continuous paper P, and starts the heat fixing of the continuous paper P by the fixing unit 124 (step S25: fixing step)

[0094] Next, the CPU 91 detects the fixing temperature from the temperature sensor of the fixing unit 124 (step S27: [arrow (d) in FIG. 3]). Furthermore, the width in the CD direction of the continuous paper P that has undergone heat fixing after passing through the fixing unit 124 is detected by the reading scanner 311 of the image reading device 3 (step S29: width detection step [arrow (b) in FIG. 3]).

[0095] Then, the shrinkage amount output unit 911 obtains the shrinkage rate ratio Sr in the same manner as step S7 in FIG. 8 described above (step S31). Furthermore, the shrinkage amount output unit 911 obtains the shrinkage rate Fr in the FD direction from the shrinkage rate in the CD direction, performs correction based on the moisture content of the continuous paper P and the fixing conditions, and outputs the corrected shrinkage rate αβγδFr in the FD direction (step S33: shrinkage amount output step).

[0096] Also in this case, the correction unit 912 corrects the image data to be formed by the image forming unit 12 based on the output shrinkage rate in the FD direction after correction and the shrinkage rate in the CD direction described above [arrow (c) in FIG. 3], and causes the image forming to be executed based on the corrected image (step S35), and ends the process.

[0097] [Operation Example (3)] The shrinkage characteristic information for the shrinkage output unit 911 to output the shrinkage rate in the FD direction of the continuous paper P may include the tension of the continuous paper P on the downstream side in the conveyance direction of the fixing unit 124. That is, by including the tension applied to the continuous paper P during the conveyance of image formation between the fixing unit 124 and the conveyance roller 76 of the post-processing device 7 in the shrinkage characteristic information, the shrinkage rate in the FD direction of the continuous paper P can be output more appropriately.

[0098] The tension of the continuous paper P between the fixing unit 124 and the conveyance roller 76 can be adjusted according to the speed difference of these target speeds by performing speed control so that the downstream side becomes faster with respect to the fixing motor 127 and the conveyance motor 77 of the fixing unit 124. Also, the tension of the continuous paper P can be adjusted according to the torque difference of these target torques by performing torque control so that the downstream torque becomes larger with respect to the fixing motor 127 and the conveyance motor 77 of the fixing unit 124. Here, the case of performing speed control on the fixing motor 127 and the conveyance motor 77 is illustrated.

[0099] The above tension of the continuous paper P during conveyance can be arbitrarily set from, for example, the operation display unit 14, and the set value is stored in a predetermined storage area in the second control unit 9. The second control unit 9 holds table data that determines the conveyance speeds of the fixing unit 124 and the conveyance roller 76 in order to generate an appropriate speed difference corresponding to the set tension value of the continuous paper P, and refers to this. However, the second control unit 9 may be configured to output each conveyance speed from the set tension by calculation.

[0100] As shown in the diagram of FIG. 14(A), the tension of the continuous paper P tends to increase the shrinkage rate of the continuous paper P as it becomes smaller. Then, as shown in FIG. 14(B), the second control unit 9 holds the data of the correspondence table of the change rate ε of the shrinkage rate based on the tension of the continuous paper P in the ROM 92 or the HDD 94. This table defines the change rate ε of the shrinkage rate in the FD direction of the continuous paper P with respect to the shrinkage rate at the reference tension for each of a plurality of tension values. Note that the reference value of the tension is set to 30 [N].

[0101] When the shrinkage amount output unit 911 acquires the set value of the tension of the continuous paper P from its storage area, it obtains the change rate ε by referring to the table of FIG. 14(B) above. Then, it multiplies the change rate ε by the shrinkage rate αFr in the FD direction of the continuous paper P based on the shrinkage rate ratio specified from the physical property values (paper thickness, grain direction, moisture content) of the continuous paper P described above to perform correction according to the tension of the continuous paper P.

[0102] An operation example (3) in the above image forming system 10 will be described based on the flowcharts of FIGS. 3 and 15. In this operation example (3) as well, the CPU 91 of the second control unit 9 mainly executes overall operation control based on the control program.

[0103] The CPU 91 starts the conveyance of the continuous paper P (step S41), similar to the case of operation example (1). Note that the CPU 91 sets the target speeds of the fixing motor 127 of the fixing unit 124 and the conveyance motor 77 of the post-processing device 7 so that a speed difference corresponding to the set tension of the continuous paper P occurs, and controls to maintain this. Also, the CPU 91 does not execute image formation on the continuous paper P by the image forming unit 12, but only executes heat fixing by the fixing unit 124 on the continuous paper P under the same conditions as during image formation (fixing process).

[0104] Then, the CPU 91 detects the physical property values (paper thickness, grain direction, moisture content) of the continuous paper P being conveyed by the media sensor 15 (step S43: characteristic acquisition step [arrow (a) in FIG. 3]).

[0105] Next, the shrinkage amount output unit 911 acquires the set tension of the continuous paper P (step S45: [arrow (e) in FIG. 3]). Furthermore, the width in the CD direction of the continuous paper P that has undergone heat fixing through the fixing unit 124 is detected by the reading scanner 311 of the image reading device 3 (step S47: width detection step [arrow (b) in FIG. 3]).

[0106] Then, the shrinkage amount output unit 911 acquires the shrinkage rate ratio Sr in the same manner as step S7 in FIG. 8 described above (step S49). Furthermore, the shrinkage amount output unit 911 obtains the shrinkage rate Fr in the FD direction from the shrinkage rate in the CD direction, performs correction based on the moisture content and tension of the continuous paper P, and outputs the corrected shrinkage rate αεFr in the FD direction (step S51: shrinkage amount output step).

[0107] Also in this case, the correction unit 912 corrects the image data of the formation target by the image forming unit 12 based on the output shrinkage rate in the FD direction and the shrinkage rate in the CD direction described above [arrow (c) in FIG. 3], and causes image formation to be executed based on the corrected image (step S53). Then, the process ends.

[0108] Note that in the correction process of the shrinkage rate in the FD direction in the above operation example (3), correction of the shrinkage rate in the FD direction based on the fixing condition information of the fixing unit 124 may also be performed multiplicatively.

[0109] [Operation Example (4)] In the above-described operation example (1), the case where the shrinkage rate in the FD direction is output once was exemplified, but the shrinkage rate in the FD direction may be re-output according to a predetermined execution condition. For example, the execution condition for re-output may be achieved by integration, such as the number of images formed on the continuous paper P, the conveyance length of the continuous paper P, the elapsed time since the start of image formation, etc. Further, as a result of the formed image being read by the reading unit 31, when the image size has shrunk more than the threshold value, etc., the occurrence of a specified state may be used as an execution condition.

[0110] An operation example (4) in the above image forming system 10 will be described based on the flowcharts of FIGS. 3 and 16. In this operation example (4) as well, the CPU 91 of the second control unit 9 mainly executes overall operation control based on a control program. Also, in this operation example (4), for steps with the same content as those in the above-described operation example (1), the same step numbers are assigned, and the same explanations are omitted, and mainly only different steps will be described.

[0111] When image formation is performed on the continuous paper P in consideration of the shrinkage rate in the FD direction by the processing up to steps S1 to S11, the shrinkage amount output unit 911 determines whether the execution condition for re-outputting the shrinkage rate in the FD direction is achieved (step S111). If the execution condition is not achieved, it is determined whether the continuous paper P is near the end (step S113), and if it is near the end, the entire image formation operation is terminated. If the continuous paper P is not near the end, the process returns to step S11, and the correction unit 912 corrects the image data in consideration of the current shrinkage rate in the FD direction, and performs image formation based on the image data on the continuous paper P.

[0112] On the other hand, if the execution condition for re-outputting the shrinkage rate in the FD direction is achieved, the process returns to step S3, and the physical property value of the continuous paper P is detected, the width in the CD direction of the continuous paper P is detected, the shrinkage rate ratio is obtained, and correction based on the moisture content is performed (steps S3 to S9), and newly, the shrinkage rate in the FD direction is re-output. And thereafter, the correction unit 912 corrects the image data in consideration of the new shrinkage rate in the FD direction, and performs image formation based on the image data (step S11).

[0113] As described above, in the image forming system 10, even when there are fluctuations in the shrinkage state of the continuous paper P for some reason, a new appropriate shrinkage rate in the FD direction can be obtained, suppressing the influence of the fluctuations, and enabling continuous image formation.

[0114] In addition, in the correction process of the shrinkage rate in the FD direction in the above operation example (4), correction of the shrinkage rate in the FD direction based on the fixing condition information of the fixing unit 124 and correction of the shrinkage rate in the FD direction based on the tension of the continuous paper P may also be performed multiplicatively.

[0115] [Operation Example (5)] FIG. 17(A) is a plan view of the continuous paper P when post-processing (for example, CD cutting process or crease process) is properly performed, and FIG. 17(B) is a plan view of the continuous paper P when improper post-processing is performed under the influence of shrinkage in the FD direction. When performing the CD cutting process or the crease process, on the premise that the continuous paper P is being conveyed at a specified conveyance speed, a cutter for performing CD cutting or a member for performing the crease process is operated at an appropriate timing to perform post-processing according to the target dimensions in the FD direction.

[0116] When the continuous paper P is conveyed at the target conveyance speed without shrinkage, as shown in FIG. 17(A), it is possible to perform post-processing according to the appropriate target dimensions in the FD direction. On the other hand, when the continuous paper P shrinks, since the continuous paper P is constrained by the fixing roller 125 and the pressure roller 126 of the fixing unit 124, a speed reduction corresponding to the shrinkage rate occurs, and as shown in FIG. 17(B), even if the operation timing is appropriate, the post-processing deviates from the target dimensions.

[0117] Therefore, the post-processing control unit 913 corrects the operation timing of the post-processing device 7 based on the shrinkage rate in the FD direction output by the shrinkage amount output unit 911. Specifically, on the premise that the continuous paper P is experiencing a reduction in conveyance speed corresponding to the shrinkage rate in the FD direction, operation control is performed to delay the operation timing of the post-processing device 7 by the amount of reduction in conveyance speed.

[0118] Next, an operation example (5) involving post-processing in the image forming system 10 will be described based on the flowcharts of FIGS. 3 and 18. In this operation example (5) as well, the CPU 91 of the second control unit 9 mainly executes overall operation control based on a control program. Also, in this operation example (5), for steps with the same content as those in the aforementioned operation example (1), the same step numbers are assigned, and the same explanations are omitted, and only the mainly different steps will be described.

[0119] When image formation with correction based on the shrinkage rate in the FD direction output by the processing up to steps S1 to S11 is performed, the post-processing control unit 913 performs operation control to execute post-processing (CD cutting process or creasing process) on the continuous paper P on which the image is formed at a timing considering the shrinkage rate in the FD direction (step S121), and ends the process.

[0120] For example, an example is given where images of 90 [mm] are formed at intervals of 100 [mm] in the FD direction, the target conveyance speed is 100 [mm / s], and post-processing is performed at intervals of 1 [s] so that CD cutting or the like is performed at intervals of 100 [mm]. Under the above premise, when the shrinkage rate in the FD direction due to fixing occurs at 1%, the conveyance speed of the continuous paper P becomes 99 [mm / s]. On the other hand, since the formed image is corrected by the shrinkage rate output by the shrinkage amount output unit 911, images of 90 [mm] are formed at intervals of 100 [mm] regardless of the shrinkage of the continuous paper P. In contrast, the post-processing control unit 913 performs correction to delay the operation timing of the post-processing device 7 to 100 / 99 times the normal timing, and performs control to execute post-processing at intervals of 100 / 99 [s], so that post-processing such as CD cutting is performed at intervals of 100 [mm], and post-processing can be performed at an appropriate position with respect to the formed image.

[0121] In addition, in the correction process of the shrinkage rate in the FD direction in the above operation example (5), the correction of the shrinkage rate in the FD direction based on the fixing condition information of the fixing unit 124 and the correction of the shrinkage rate in the FD direction based on the tension of the continuous paper P may also be performed multiplicatively.

[0122] [Operation Example (6)] In the above-described operation example (1), when the shrinkage rate in the FD direction is output, an example was shown in which the image formation is performed by the correction unit 912 with correction considering the output shrinkage rate in the FD direction. However, a process of determining the propriety according to the magnitude of the shrinkage rate in the FD direction may be added by the determination unit 914. Hereinafter, the operation example (6) with the determination process by the determination unit 914 added in the image forming system 10 will be described based on the flowcharts of FIGS. 3 and 19. In this operation example (6) as well, the CPU 91 of the second control unit 9 mainly executes overall operation control based on the control program. Also, in this operation example (6), for the steps having the same content as those in the above-described operation example (1), the same step numbers are assigned, and the same explanations are omitted, and only the mainly different steps will be described.

[0123] When the shrinkage rate in the FD direction is output by the processing up to steps S1 to S9, the determination unit 914 compares it with a specified threshold value and determines whether the shrinkage rate in the FD direction is within the allowable range (step S141). And when the determination unit 914 determines based on the threshold value that the output shrinkage rate in the FD direction is within the allowable range, the correction unit 912 corrects the image data in consideration of the shrinkage rate in the FD direction, and performs image formation on the continuous paper P based on the image data (step S143), and ends the process.

[0124] Also, when the determination unit 914 determines based on the threshold value that the output shrinkage rate in the FD direction is outside the allowable range, image formation is not performed, and the CPU 91 performs notification processing such as notifying that excessive shrinkage has occurred in the continuous paper P through, for example, the operation display unit 14 or the like, and ends the process.

[0125] In addition, in the correction process of the shrinkage rate in the FD direction in the above operation example (6), the correction of the shrinkage rate in the FD direction based on the fixing condition information of the fixing unit 124 and the correction of the shrinkage rate in the FD direction based on the tension of the continuous paper P may also be performed multiplicatively.

[0126] [Technical Effects of Embodiments of the Invention] As described above, in the image forming system 10, since the second control unit 9 includes a shrinkage amount output unit 911 that outputs the shrinkage rate of the continuous paper P in the FD direction by the fixing unit 124 based on the width of the continuous paper P detected by the reading scanner 311 of the image reading device 3 and the shrinkage characteristic information of the continuous paper P, it is possible to suppress the influence of the decrease in the conveyance speed after shrinkage and obtain the shrinkage rate in the FD direction with higher accuracy.

[0127] Further, in the image forming system 10, since the shrinkage characteristic information of the continuous paper P includes the paper grain direction, the moisture content of the paper, and the thickness, the shrinkage amount output unit 911 can output the shrinkage rate of the continuous paper P in the FD direction with higher accuracy in consideration of the influence of the paper grain direction, the moisture content of the paper, and the thickness that affect the shrinkage rate of the continuous paper P.

[0128] In addition, since the second control unit 9 stores a table as information for specifying the shrinkage rate ratio in the CD direction and the FD direction of the continuous paper P for each of the plurality of paper grain directions and thicknesses, and the shrinkage amount output unit 911 outputs the shrinkage rate in the FD direction in consideration of the table, it is possible to output the shrinkage rate in the FD direction promptly.

[0129] Further, in the image forming system 10, when the shrinkage characteristic information of the continuous paper P includes at least one of the fixing temperature, fixing pressure, fixing speed, and fixing time, which are fixing condition information, the shrinkage amount output unit 911 can output the shrinkage rate of the continuous paper P in the FD direction with higher accuracy in consideration of the influence of the fixing temperature, fixing pressure, fixing speed, or fixing time that affects the shrinkage rate of the continuous paper P.

[0130] In addition, in the image forming system 10, when the shrinkage characteristic information of the continuous paper P includes the tension of the continuous paper P between the fixing unit 124 and the conveying roller 76, the shrinkage amount output unit 911 can output the shrinkage rate of the continuous paper P in the FD direction with higher accuracy in consideration of the influence of the tension of the continuous paper P that affects the shrinkage rate of the continuous paper P. In addition, since the tension of the continuous paper P is determined based on the conveyance speed difference or torque difference between the fixing unit 124 and the conveying roller 76, the tension of the continuous paper P can be maintained constant by controlling these drive sources. Along with this, it becomes possible to maintain the shrinkage rate of the continuous paper P in the FD direction constant. Therefore, when correcting the operations of image formation and post-processing on the continuous paper P according to the shrinkage rate of the continuous paper P in the FD direction, it becomes possible to perform appropriate correction over a long period with the shrinkage rate output once.

[0131] In addition, in the image forming system 10, since the second control unit 9 includes a correction unit 912 that corrects the size of the image formed by the image forming unit 12 based on the shrinkage rate of the continuous paper P in the FD direction output by the shrinkage amount output unit 911, it becomes possible to suppress the shrinkage of the formed image and optimize the size of the image.

[0132] In addition, in the image forming system 10, since the second control unit 9 includes a determination unit 914 that determines the quality of the shrinkage state based on the shrinkage rate output by the shrinkage amount output unit 911, it becomes possible to determine whether to execute processes such as image formation when the shrinkage of the continuous paper P becomes excessive.

[0133] In addition, in the image forming system 10, since the reading scanner 311 is a line sensor having a plurality of light receiving elements arranged along the CD direction, the width of the continuous paper P that has shrunk in the CD direction can be accurately detected. Along with this, it also becomes possible to accurately obtain the shrinkage rate in the FD direction. Furthermore, since the reading scanner 311 is a sensor capable of reading an image formed on the continuous paper P, the reading scanner 311 provided as the image reading unit can also be utilized as the detection unit. Therefore, it is not necessary to specifically provide a detection unit for the width of the continuous paper P in the CD direction, and it is possible to facilitate the manufacture of the apparatus from the perspective of reducing the number of components such as sensors, and also to reduce the size of the apparatus by eliminating the need for extra installation space.

[0134] Also, in the image forming system 10, since the second control unit 9 includes a post-processing control unit 913 that performs operation control of the post-processing executed by the post-processing apparatus 7 by reflecting the shrinkage rate output by the shrinkage amount output unit 911, it is possible to perform post-processing at an appropriate position in the FD direction with respect to the formed image of the continuous paper P. In particular, in the case of a cutting process along the CD direction or a creasing process along the CD direction, the execution position in the FD direction is important. However, the operation is optimized by the post-processing control unit 913, and it is possible to maintain high processing accuracy even if shrinkage of the continuous paper P occurs.

[0135] [Others] The details shown in the above-described embodiments of the invention can be appropriately changed without departing from the spirit of the invention. For example, the shrinkage characteristic information of the continuous paper P may include information indicating the paper type, basis weight, or stiffness. Regarding these paper types and basis weights, it is possible to detect them by the above-described optical sensor of the media sensor 15. Also, regarding the stiffness, it is possible to detect it by the above-described acceleration sensor of the media sensor 15. Since any of the above paper type, basis weight, or stiffness is correlated with the shrinkage rate of the continuous paper P in the FD direction, it is preferable to prepare data of a correspondence table of the change rate of the shrinkage rate based on the paper type, basis weight, or stiffness, as shown in FIG. 7 described above, in the ROM 92 or HDD 94 as the storage unit. When the shrinkage amount output unit 911 outputs the shrinkage rate in the FD direction of the continuous paper P, it is preferable to refer to the above correspondence table and correct the shrinkage rate in the FD direction based on the change rate corresponding to the paper type, basis weight, or stiffness detected by the media sensor 15. This makes it possible to obtain the shrinkage rate in the FD direction of the continuous paper P with higher accuracy.

[0136] Moreover, although the continuous paper P has been exemplified as the recording medium of the image forming system 10, the present invention is not limited to this, and a long paper (long sheet) may be used as the recording medium. Further, the recording medium is not limited to paper, and may be a sheet material made of other materials such as resin. For example, when using a long paper having a length in the FD direction exceeding the path length from the fixing unit 124 to the reading scanner 311 as the recording medium, reading by the reading scanner 311 is performed in a state where the conveyance speed has decreased due to the shrinkage of the fixing unit 124, so it becomes difficult to detect the shrinkage rate in the FD direction. Therefore, even in the case of such a long paper, it is effective to output the shrinkage rate in the FD direction from the width in the CD direction of the long paper.

[0137] In the above embodiment of the invention, the shrinkage rate in the FD direction of the continuous paper P is output. However, instead of or together with the shrinkage rate, the shrinkage amount in the FD direction of the recording medium may be output. In that case, means for detecting the conveyance amount of the continuous paper P without considering the shrinkage in the fixing unit 124 and means for detecting the conveyance amount of the continuous paper P upstream of the fixing unit 124 in the conveyance direction are provided, and the shrinkage amount can be output by multiplying the obtained conveyance amount by the shrinkage rate in the FD direction output by the shrinkage amount output unit 911. The above shrinkage amount is, for example, the shrinkage amount generated with respect to a predetermined conveyance amount (for example, 1 [m]), the shrinkage amount generated per unit time, the shrinkage amount with respect to the known size in the FD direction of the formed image, etc., the shrinkage amount with respect to some reference length in the FD direction.

Explanation of Signs

[0138] 1 Image forming apparatus 3 Image reading apparatus 31 Reading unit 311 Reading Scanner (Detection Unit) 312 Colorimeter 5 Paper Feeding Device 6 Paper Recycling Device 7 Post-processing Device (Post-processing Unit) 71 - 74 Post-processing Modules 76 Conveyor Roller 77 Conveyor Motor 8 First Control Unit 9 Second Control Unit (Control Device) 91 CPU 911 Shrinkage Output Unit (Output Unit) 912 Correction Unit 913 Post-processing Control Unit 914 Judgment Unit 92 ROM (Memory Unit) 94 HDD (Memory Unit) 10 Image Formation System 12 Image Formation Unit 124 Fixing Unit 125 Fixing Roller 126 Pressure Roller 127 Fixing Motor 15 Media Sensor P Continuous Paper (Recording Medium)

Claims

1. A control device for an image forming system including an image forming unit that forms an image on a recording medium made of a continuous sheet or a long sheet, obtaining a width of the recording medium on the downstream side in the conveyance direction of the recording medium from a fixing unit included in the image forming unit, and based on the width of the recording medium and shrinkage characteristic information of the recording medium, outputting a shrinkage amount or shrinkage rate of the recording medium in the conveyance direction by the fixing unit. A control device characterized by comprising an output unit.

2. The control device according to claim 1, wherein the shrinkage characteristic information of the recording medium includes information indicating a paper type.

3. The control device according to claim 1 or claim 2, wherein the shrinkage characteristic information of the recording medium includes information indicating a grain direction of the paper.

4. comprising a storage unit that stores information specifying a shrinkage rate ratio between the width direction and the conveyance direction of the recording medium for each of a plurality of the grain directions of the paper, The control device according to claim 3, wherein the output unit outputs the shrinkage amount or shrinkage rate in consideration of the information specifying the shrinkage rate ratio.

5. The control device according to any one of claims 1 to 4, wherein the shrinkage characteristic information of the recording medium includes information indicating at least one of a moisture content or a thickness of the paper.

6. The control device according to any one of claims 1 to 5, wherein the shrinkage characteristic information of the recording medium includes information indicating at least one of a basis weight or a stiffness of the paper.

7. The control device according to any one of claims 1 to 6, wherein the shrinkage characteristic information of the recording medium includes fixing condition information.

8. The control device according to claim 7, wherein the fixing condition information includes information indicating at least one of a fixing temperature, a fixing pressure, a fixing speed, and a fixing time.

9. The control device according to any one of claims 1 to 8, characterized in that the shrinkage characteristic information of the recording medium includes the tension of the recording medium on the downstream side of the fixing unit in the conveyance direction.

10. The control device according to claim 9, characterized in that the shrinkage characteristic information of the recording medium includes, as the tension of the recording medium, the tension of the recording medium between the fixing unit and a conveyance roller of the recording medium provided on the downstream side of the fixing unit in the conveyance direction.

11. The control device according to claim 10, characterized in that the tension of the recording medium is based on a conveyance speed difference or a torque difference between the fixing unit and the conveyance roller.

12. The control device according to any one of claims 1 to 11, characterized by comprising a correction unit that corrects the size of an image formed by the image forming unit based on the shrinkage amount or shrinkage rate output by the output unit.

13. The control device according to any one of claims 1 to 12, characterized by comprising a determination unit that performs a pass / fail determination on the shrinkage amount or shrinkage rate output by the output unit.

14. An image forming system, characterized by comprising the control device according to any one of claims 1 to 13.

15. Comprising a detection unit that detects the width of the recording medium on the downstream side of the fixing unit of the image forming unit in the conveyance direction of the recording medium, The image forming system according to claim 14, characterized in that the detection unit is a sensor having a plurality of light receiving elements arranged along the width direction of the recording medium.

16. The image forming system according to claim 15, characterized in that the sensor is capable of reading an image formed on the recording medium.

17. Comprising a post-processing unit that performs post-processing on the recording medium on which an image is formed, The image forming system according to any one of claims 14 to 16, wherein the control device includes a post-processing control unit that controls the operation of the post-processing unit in accordance with the shrinkage amount or shrinkage rate.

18. The image forming system according to claim 17, wherein the post-processing unit executes, as the post-processing, cutting or creasing processing along the width direction of the recording medium.

19. A control method for an image forming system including an image forming unit that forms an image on a recording medium made of a continuous sheet or a long sheet, the method comprising: obtaining a width of the recording medium on a downstream side in a conveyance direction of the recording medium from a fixing unit included in the image forming unit, and outputting a shrinkage amount or shrinkage rate of the recording medium in the conveyance direction by the fixing unit based on the width of the recording medium and shrinkage characteristic information of the recording medium.

20. A program for causing a computer of an image forming system including an image forming unit that forms an image on a recording medium made of a continuous sheet or a long sheet to function as: an output unit that obtains a width of the recording medium on a downstream side in a conveyance direction of the recording medium from a fixing unit included in the image forming unit, and outputs a shrinkage amount or shrinkage rate of the recording medium in the conveyance direction by the fixing unit based on the width of the recording medium and shrinkage characteristic information of the recording medium. ​

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