JP6547773B2 - Image forming apparatus and program - Google Patents

Description

  The present invention relates to an image forming apparatus and a program.

  Conventionally, a sheet surface including an image formed by an image forming apparatus such as a copying machine or a printer is read using a sensor such as a charge coupled device image sensor (CCD) or the like as a result of reading of the color of the printed image. There is a system to monitor the presence or absence of fluctuations. In this system, a patch image of a color to be monitored is printed on the sheet edge, and the color of the printed patch image is measured by a sensor (hereinafter referred to as an “image reading unit”). When a variation in tint is detected in the patch image measured by the image reading unit, color correction is applied such that the color to be printed becomes the reference color each time based on the measured color.

  FIG. 1 is a diagram showing an example of a conventional patch image printed by a conventional image forming apparatus. An image ("A" in the alphabet) is formed in the image forming area ImA of the sheet Sh, and a patch image is formed in a portion (area outside the image forming area) around the image forming area ImA. In FIG. 1, patch images AP1 and AP2 and patch images are formed in areas outside the image forming area at the upper end of the sheet and the lower end of the sheet (the right and left ends of the sheet in the sheet conveyance direction (sub scanning direction) Ds). AP3 and AP4 are formed. After completion of color correction by the image forming apparatus, the user can obtain a high quality product (printed matter) by cutting an area outside the image formation area around the image formation area ImA. Further, in the above-described system, it is possible to detect positional deviation in the printed image according to the result of reading the image by the image reading unit.

  However, in the above-described system, since the sheet after fixing is performed is measured, it is affected by the phenomenon of “thermochromism” in which the chromaticity of the patch image to be measured changes with temperature. "Thermochromism" is a phenomenon in which the molecular structure forming a coloring material such as toner or ink is reversibly changed by heat.

  Patent Document 1 proposes a technique for sufficiently reducing the temperature of the sheet by stopping or conveying the sheet at a low speed in the discharge path in order to suppress the thermochromism phenomenon. Patent Document 2 proposes a technique for correcting a color measurement result according to the temperature of a sheet detected by a temperature sensor.

JP, 2013-54324, A JP, 2013-114180, A

  However, in the technique described in Patent Document 1, when stopping the conveyance of the sheet, the productivity is deteriorated. Even when the temperature of the sheet is lowered before the image is read by conveying the sheet at a low speed, in the case where the temperature sensor is located in the vicinity of the image reader, the sheet is conveyed while the image reader reads the image. When the speed changes, the read image is distorted. In this case, the positional deviation in the printed image can not be properly detected.

  Further, in the technique described in Patent Document 2, when the temperature of the sheet being conveyed can not be accurately measured, there is a possibility that unnecessary color correction may be performed based on an incorrect temperature measurement result. The temperature sensor has a response time, and even if the sheet comes on the temperature sensor, the accurate temperature can not be measured unless a predetermined time has elapsed since the start of the temperature measurement. That is, in order to accurately measure the temperature of the sheet being conveyed, it is necessary to slow the conveyance speed of the sheet sufficiently. However, if the paper transport speed is sufficiently slowed down, the productivity of the image forming apparatus is reduced.

  The present invention has been made to solve these problems. An object of the present invention is to enable appropriate color correction in accordance with a properly measured paper temperature without unnecessarily reducing the productivity of the image forming apparatus.

  An image forming apparatus according to an aspect of the present invention includes an image forming unit, an image reading unit, a temperature measurement unit, a color correction unit, and a conveyance control unit. The image forming unit forms an image on a sheet. The image reading unit reads a sheet of paper on which an image is formed by the image forming unit. The temperature measurement unit measures the temperature of the sheet on which the sheet has been read by the image reading unit. The color correction unit corrects the color of the image formed by the image forming unit based on the image on the paper surface read by the image reading unit and the temperature of the sheet measured by the temperature measurement unit. The conveyance control unit controls the speed at which the sheet is conveyed according to the arrangement relationship between the image reading unit and the sheet temperature measurement unit and the sheet size of the sheet.

  According to at least one aspect of the present invention, it is possible to perform appropriate color correction in accordance with the properly measured sheet temperature without unnecessarily reducing the productivity of the image forming apparatus. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

It is a figure which shows the example of the conventional common patch image. FIG. 1 is a schematic view showing a configuration example of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram showing an example of configuration of a control system of an image forming apparatus main body according to an embodiment of the present invention. It is a block diagram showing an example of functional composition of a post-processing device concerning one embodiment of the present invention. FIG. 7 is a sheet operation diagram when the first control according to the embodiment of the present invention is performed. FIG. 7 is a sheet operation diagram when second control according to an embodiment of the present invention is performed. FIG. 14 is a sheet operation diagram when the third control according to the embodiment of the present invention is performed. FIG. 18 is a sheet operation diagram when the fifth control according to the embodiment of the present invention is performed. 5 is a flowchart illustrating a procedure of color correction control in an image forming apparatus main body according to an embodiment of the present invention. 7 is a flowchart showing a procedure of sheet-to-sheet and conveyance speed calculation processing in the image forming apparatus main body according to the embodiment of the present invention. It is an explanatory view showing an example of composition of a sheet interval / conveyance speed calculation table concerning one embodiment of the present invention. 5 is a flowchart illustrating a procedure of control for color correction in the post-processing device according to the embodiment of the present invention. 5 is a flowchart illustrating a procedure of control for color correction in the post-processing device according to the embodiment of the present invention.

  Hereinafter, an image forming apparatus and a program according to an embodiment of the present invention will be described with reference to the attached drawings. In addition, about the component which has a substantially the same function or structure in each figure, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

<Overall Configuration of Image Forming Apparatus>
First, the overall configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 2 is a schematic view showing a configuration example of the image forming apparatus 1 according to the present embodiment. FIG. 2 describes elements considered necessary for the explanation of the present invention or related elements, and the image forming apparatus is not limited to this example. In the present embodiment, as the image forming apparatus 1, for example, a multifunction peripheral (MFP: Multi-functional peripherals) having functions of a scanner, a printer, etc. and operating each function with a touch panel type operation unit is described as an example. Do.

  The image forming apparatus 1 includes an image forming apparatus main body 10 and a post-processing device 40. The image forming apparatus main body 10 and the post-processing apparatus 40 are connected in series. The image forming apparatus main body 10 forms an image on the sheet Sh by, for example, an electrophotographic method in which an image is formed using static electricity. As a printing method, for example, a tandem type in which toner images of four colors (basic colors) of yellow (Y), magenta (M), cyan (C), and black (K) can be adopted.

  Image formation by the image forming apparatus main body 10 is performed based on a job received from a PC (Personal Computer) 120 (see FIG. 3) or the like. When the received job is a job for performing color monitoring and correction, the image forming apparatus main body 10 forms a patch image as shown in FIG. 1 on the sheet Sh, and a patch image is formed. The sheet Sh is output and conveyed to the post-processing device 40.

  The post-processing apparatus 40 performs post-processing on the sheet Sh discharged from the image forming apparatus main body 10, and discharges the sheet Sh subjected to the post-processing to the sheet discharge tray 50. In the present embodiment, the post-processing device 40 has a function of reading a patch image, a function of measuring the temperature of the sheet Sh on which the patch image has been read, and image formation of the patch image reading result and the sheet temperature. It also has a function of transmitting to the device body 10. The image forming apparatus main body 10 uses the reading result and the measurement result of the sheet temperature sent from the post-processing apparatus 40 to match the color of the image printed on the sheet Sh with a predetermined reference color. A correction is made. The configuration of each part of the image forming apparatus main body 10 and the post-processing apparatus 40 will be described in more detail with reference to FIG. 2 as well.

(Configuration of image forming apparatus main body)
The image forming apparatus main body 10 includes an image input unit 11 and an operation display unit 13. The image input unit 11 includes paper feed trays 20A and 20B, a conveyance path 21, an image forming unit 30, and an automatic document feeder (ADF) 12. The sheet Sh is accommodated in the sheet feeding trays 20A and 20B. The conveyance path 21 conveys the sheet Sh accommodated in the sheet feeding trays 20A and 20B to the image forming unit 30.

  The image forming unit 30 includes four image forming units 31Y, 31M, 31C, and 31K corresponding to the respective colors Y, M, C, and K. Each image forming unit 31 includes a charging unit (not shown), an LED writing unit (laser light source) and a developing unit, and photosensitive drums 32Y, 32M, 32C, and 32K. The image forming unit 30 further includes an intermediate transfer belt 34, a secondary transfer unit 35, and a fixing unit 36.

  The images formed on the photosensitive drums 32Y, 32M, 32C, and 32K are primarily transferred to the intermediate transfer belt 34. The secondary transfer portion 35 secondarily transfers the toner images of the respective colors primarily transferred onto the intermediate transfer belt 34 to the sheet Sh conveyed on the conveyance path 21. A color image is formed by secondarily transferring the toner image of each color on the intermediate transfer belt 34 to the sheet Sh. The fixing unit 36 applies pressure and heat to the conveyed sheet Sh to fix the color image on the sheet Sh. The sheet Sh on which the fixing process has been performed by the fixing unit 36 is conveyed to the post-processing device 40 through the conveyance path 21.

  In the present embodiment, an example is described in which the image forming unit 30 performs image formation using four colors of Y, M, C, and K, but the present invention is not limited to this. For example, the present invention may be applied to a configuration called "corporate color" having a feature for forming a color or the like that symbolizes a company or a group.

  The operation display unit 13 includes a display unit 131 and an operation unit 132 configured by a touch panel. The display unit 131 is configured of, for example, a liquid crystal panel or the like, and the content of operation by the user, setting information and the like are displayed on the screen. The operation unit 132 includes, for example, a touch sensor, and inputs an operation from a user instructing start of a job for image formation processing, a job for monitoring and correcting a color, and the like. Note that the operation unit 132 can be configured with a mouse, a tablet, or the like, and can be configured separately from the display unit 131.

(Configuration of post-processing device)
The post-processing device 40 includes an image reading unit 41 and a temperature measuring unit 42. The image reading unit 41 includes, for example, a sensor such as a CCD, and reads a patch image formed on the sheet Sh discharged from the image forming apparatus main body 10. The temperature measurement unit 42 measures the temperature of the sheet Sh on which the image reading unit 41 has read the patch image. The image reading result (read image) of the image reading unit 41 and the temperature of the sheet Sh (sheet temperature measurement result) measured by the temperature measuring unit 42 are transmitted to the image forming apparatus main body 10.

<Configuration of Control System of Image Forming Apparatus>
Next, the configuration of the control system of the image forming apparatus main body 10 will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration example of a control system of the image forming apparatus according to the present embodiment. Note that FIG. 3 describes the elements considered necessary for the explanation of the present invention or the related elements, and the configuration of the control system of the image forming apparatus is not limited to this example.

  The image forming apparatus main body 10 includes a control device 100, a storage device 101, a communication I / F (Interface) 102, a receiving unit 103, and a sheet conveyance unit 104. The control device 100 includes an arithmetic processing unit (not shown) and a memory, and is an image forming apparatus main body 10 for feeding the sheet Sh, forming an image on the sheet Sh, discharging the sheet Sh on which the image is formed, and the like. A series of controls related to the image forming process of The arithmetic processing unit is configured of, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The memory is made of, for example, a random access memory (RAM), a read only memory (ROM), or the like. The ROM stores a program executed by the CPU of the control device 100 or data used when executing the program.

  The storage device 101 is configured of, for example, a memory or a hard disk drive (HDD). The storage device 101 stores parameters used when the arithmetic processing unit of the control device 100 executes a program, or data obtained by executing the program. The storage device 101 also stores patch image information. The program executed by the arithmetic processing unit of the control device 100 may be stored in the storage device 101 instead of the memory of the control device 100.

  The communication I / F 102 is an interface that controls data transmission / reception performed with the PC 120 connected via a network or a dedicated line. The communication I / F 102 is configured of, for example, a NIC (Network Interface Card). The receiving unit 103 receives the reading result of the patch image and the measurement result of the sheet temperature transmitted from the post-processing device 40, and outputs the result to the control device 100. The sheet conveyance unit 104 drives the conveyance path 21 under the control of the control device 100.

  The control device 100 further includes a color correction unit 111 and a conveyance control unit 112. The color correction unit 111 performs color correction based on the reading result of the patch image and the measurement result of the sheet temperature transmitted from the post-processing apparatus 40. The conveyance control unit 112 calculates the conveyance speed of the sheet Sh suitable for reading the patch image by the image reading unit 41 based on the sheet size of the sheet Sh passing through the conveyance path 21 and the number of monitoring patches. Then, the conveyance control unit 112 controls the sheet conveyance unit 104 so that the sheet Sh can be conveyed at the calculated conveyance speed. In the present embodiment, the conveyance control unit 112 performs control to perform conveyance at the highest conveyance speed at which the image reading unit 41 can read a patch image in order to prevent the productivity of the image forming apparatus main body 10 from being unnecessarily dropped. . In the case where a plurality of sheets Sh are continuously printed by the image forming apparatus main body 10, the transport control unit 112 not only transports the sheets Sh, but also the next sheet from the sheet interval, that is, the trailing edge of the preceding sheet Sh. The interval (ms) to the leading edge of the sheet Sh is also controlled. In the following description, control of the transport speed and / or control of the sheet interval are collectively referred to as "transport control".

<Functional Configuration of Post-processing Device>
Next, the configuration of functional blocks of the post-processing device 40 will be described with reference to FIG. FIG. 4 is a block diagram showing an example of a functional configuration of the post-processing device 40 according to the present embodiment. Note that FIG. 4 describes the elements considered necessary for the explanation of the present invention or the related elements, and the configuration of the control system of the post-processing apparatus is not limited to this example.

  The post-processing apparatus 40 includes a transmitting unit 43, a sheet conveying unit 44, and a control unit 45 in addition to the image reading unit 41 and the temperature measuring unit 42 described above. The transmitting unit 43 transmits the read image read by the image reading unit 41 and the temperature of the sheet Sh measured by the temperature measuring unit 42 to the image forming apparatus main body 10. The sheet conveyance unit 44 drives the conveyance path 21 under the control of the control device 100.

  The control unit 45 includes an arithmetic processing unit (not shown) and a memory, and performs a series of control related to the processing of the post-processing device 40. The arithmetic processing unit is configured of, for example, a CPU or an MPU. The memory is, for example, a RAM, a ROM, or the like. The ROM stores a program executed by the CPU of the control unit 45 or data used when executing the program.

  The control unit 45 further includes a conveyance control unit 451. The conveyance control unit 451 performs conveyance based on the information on the arrangement relationship of the image reading unit 41 and the temperature measurement unit 42 in the post-processing apparatus 40 and the information on the sheet size of the sheet Sh conveyed from the image forming apparatus main body 10. Take control. In the following description, “control for color correction” that is control performed by the image forming apparatus 1 (the image forming apparatus main body 10 and the post-processing apparatus 40) for carrying out appropriate color correction, including transport control of the sheet Sh. It is called.

<Overview of Color Correction Control by Image Forming Apparatus>
(First control)
Next, an outline of color correction control performed by the image forming apparatus 1 according to the present embodiment will be described. First, control in the case where continuous printing of the sheet Sh is not assumed (hereinafter, referred to as “first control”) will be described with reference to FIG. FIG. 5 is a sheet operation diagram showing the correspondence between the position and the time on the transport path 21 of the sheet Sh which passes through the inside of the transport path 21 of the post-processing apparatus 40 when the first control is performed. FIG. 5 shows both an operation diagram D1 of the leading end of the sheet Sh and an operation diagram Dt of the sheet rear end.

  The horizontal axis of FIG. 5 shows time (ms), and the vertical axis shows distance (mm). The distance shown on the vertical axis indicates the distance from the point “0” of the sheet Sh in the transport path 21 of the post-processing apparatus 40. A point “0” in the sheet operation diagram corresponds to a point (loading port) P0 (see FIG. 2) at which the sheet Sh transported from the image forming apparatus main body 10 is carried into the post-processing apparatus 40. The image acquisition position Ps (200 mm) on the vertical axis corresponds to the position Ps (see FIG. 2) on the transport path 21 at which a patch image is acquired by the image reading unit 41. For example, a position substantially at the center of the image reading unit 41 in the sheet conveyance direction (sub scanning direction Ds in FIG. 1) can be set at the position Ps. The sheet temperature measurement position Pt (300 mm) corresponds to a substantially central position Pt (see FIG. 2) in the sheet conveyance direction of the temperature measurement unit 42. The time shown on the horizontal axis indicates the elapsed time when the measurement of time is started with "0" (starting point) when the leading end of the sheet Sh is located at the point P0 of the post-processing apparatus 40. In the example shown in FIG. 5, the sheet size of the sheet Sh is A4s size (297 mm).

The first control is performed in the following procedure.
(1) The conveyance control unit 451 of the post-processing apparatus 40 performs the process from when the front end of the sheet Sh is carried into the post-processing apparatus 40 until the rear end of the sheet passes through the image acquisition position Ps of the image reading section 41. The sheet Sh is conveyed at the conveyance speed Sp1 (an example of a first conveyance speed). The conveyance speed Sp1 is the fastest conveyance speed at which the image reading unit 41 can read an image (image analysis). The method of calculating the transport speed Sp1 will be described in detail with reference to FIGS. 10 and 11 described later. In FIG. 5, the sheet operation diagram of the sheet Sh transported at the transport speed Sp1 is indicated by a thick solid line, and the transport speed Sp1 is assumed to be 1000 mm / s. The patch image on the sheet Sh transported at the transport speed Sp1 is read by the image reading unit 41.

  (2) The conveyance control unit 451 calculates a time Ta (an example of a first time) at the timing when the trailing edge of the sheet Sh passes through the image reading unit 41 (passes the image acquisition position Ps). The time Ta is a time during which the sheet Sh can stay on the temperature measurement unit 42 when the sheet Sh is transported at the transport speed Sh, and can be calculated by the following equation 1.

  Ta = (Pt-Ps) / Sp1 Formula 1

  That is, according to the equation 1, the time Ta is calculated by dividing the distance between the image acquisition position Ps and the sheet temperature acquisition position Pt (an example of a first distance) by the transport speed Sp1. The time Ta is shown in FIG. 5 by a double arrow having a fine dot pattern.

  (3) The transport control unit 451 determines how long the sheet Sh needs to stay on the temperature measurement unit 42 after the elapse of the time Ta. This time can be calculated using the time Ta and the measurement preparation time (response speed) Tb of the temperature measurement unit 42 (shown by the coarse dot pattern double arrow in FIG. 5). Next, the conveyance control unit 451 calculates a conveyance speed Sp2 (an example of a second conveyance speed) that enables the sheet Sh to be kept on the temperature measurement unit 42 for the calculated time. The transport speed Sp2 can be calculated by the following equation 2.

  Sp2 = (Pt-Ps) / (Tb-Ta) Formula 2

  According to the equation 2, the conveyance speed Sp2 is a time obtained by subtracting the time Ta calculated by the equation 1 from the response time Tb of the temperature measurement unit 42, and the distance between the image acquisition position Ps and the sheet temperature acquisition position Pt Calculated by dividing the first distance).

  The conveyance of the sheet Sh at the conveyance speed Sp2 is continuously performed until the trailing edge of the sheet Sh passes through the temperature measurement unit 42 (passes the image acquisition position Ps). In FIG. 5, the sheet operation diagram of the sheet Sh transported at the transport speed Sp2 is indicated by a thick broken line. In the example shown in FIG. 5, it is assumed that the response speed Tb is 600 ms. The temperature of the sheet Sh transported at the transport speed Sp2 is measured by the temperature measurement unit 42.

  (4) The transport control unit 451 returns the transport speed of the sheet Sh back to the transport speed Sp1 after the rear end of the sheet Sh passes through the temperature measurement section 42 (passes the image acquisition position Ps). Then, the transmitting unit 43 (see FIG. 4) of the post-processing device 40 measures the temperature of the sheet Sh measured by the temperature measuring unit 42 and the read image of the patch image read by the image reading unit 41. Send to

  By the first control being performed by the image forming apparatus 1, the sheet rear end of the sheet Sh is left until the image reading unit 41 passes, and after the sheet rear end of the sheet Sh passes the temperature measuring unit 42. The sheet Sh is conveyed at the highest conveyance speed Sp1 at which the image can be read. Therefore, the productivity of the image forming apparatus 1 is maintained during that time. Further, when measuring the temperature of the sheet Sh, the conveying speed of the sheet Sh is dropped to the conveying speed Sp2 in consideration of the response time Tb of the temperature measuring unit 42, so the sheet temperature measurement by the temperature measuring unit 42 is also accurately performed. It will be. That is, according to the image forming apparatus 1 of the present embodiment, appropriate color correction can be performed according to the accurately measured paper temperature without unnecessarily reducing the productivity of the image forming apparatus 1.

(Second control)
Next, control (hereinafter, referred to as “second control”) in the case where a plurality of sheets Sh are continuously printed will be described. When the transport control unit 451 performs the first control, after the previous sheet Sh passes through the temperature measurement unit 42, the transport speed of the sheet Sh is returned to the transport speed Sp1 before shifting. Therefore, if the sheet interval is not sufficiently maintained, there is a possibility that the front (preceding) sheet Sh and the next sheet Sh may collide. However, if the leading end of the next sheet Sh comes on the temperature measuring section 42 after the timing when the trailing end of the previous sheet Sh passes through the temperature measuring section 42, it is considered that the sheets do not collide with each other.

  That is, the conveyance time, which is increased by performing the first control, is added to the sheet interval Ty at the normal time (intrinsic) to make a new sheet interval Tx (an example of the second sheet interval), and this sheet interval Tx The first control can be performed while preventing the sheets Sh from colliding with each other by performing control to realize the above. The sheet interval Tx can be calculated by the following equation 3.

  Tx = Ty + (Tb-((Pt-Ps) / Sp1)) Formula 3

  According to the above equation 3, the new inter-sheet space Tx is obtained by adding the time obtained by subtracting the time Ta ((Pt−Ps) / Sp1) from the response time Tb of the temperature measurement unit 42 to the normal inter-sheet space Ty. It is calculated.

  A specific embodiment of the control for realizing the sheet interval Tx, that is, the second control will be described with reference to FIG. FIG. 6 is an operation diagram of the leading end and the trailing end of the sheet Sh when the second control is performed. In FIG. 6, an operation diagram Dl1 of the front end of the sheet Sh, an operation diagram Dt1 of the rear end of the sheet Sh, an operation diagram Dl2 of the sheet end of the next sheet Sh, and the next sheet Sh An operation diagram Dt2 of the leading end of the sheet is shown. In the example shown in FIG. 6, the sheet size of the sheet Sh is A4s size (297 mm), and the response time Tb of the image reading unit 41 is 600 ms. Further, the transport speed Sp1 is 1000 mm / s, and the sheet interval Ty at the normal time is 200 ms.

  As shown in FIG. 6, the operation of the rear end of the front sheet Sh is performed even when the first control is performed by performing transport control for holding the sheet interval Tx calculated using the above equation 3 as shown in FIG. The diagram Dt1 and the operation diagram Dl2 of the leading end of the next sheet Sh do not overlap. That is, by performing the second control, the productivity of the image forming apparatus 1 can be ensured, and the temperature of the sheet Sh can be accurately measured, while preventing the sheets Sh that are continuously conveyed from colliding with each other. Thus, it is possible to perform the first control that enables the coexistence of

(Third control)
Next, shift for temperature measurement, that is, transport control when shift to the transport speed Sp2 is unnecessary (hereinafter referred to as “third control”) will be described. For example, when the sheet size of the sheet Sh is large and the time Ta calculated by the above equation 1 becomes larger than the response time Tb of the image reading unit 41, the temperature measurement is performed without performing the control to reduce the conveyance speed. It is considered that the time for which the sheet Sh stays on the section 42 is also secured sufficiently long. In such a case, the shift to the transport speed Sp2 for accurate temperature measurement is not performed, and the transport at the transport speed Sp1 is performed.

  A specific embodiment of the third control will be described with reference to FIG. FIG. 7 shows an operation diagram D1 of the leading end of the sheet Sh and an operation diagram Dt of the rear end of the sheet when the third control is performed. In the example shown in FIG. 7, the sheet size of the sheet Sh is 700 mm, the response time Tb of the image reading unit 41 is 600 ms, and the transport speed Sp1 is 1000 mm / s.

  In the example shown in FIG. 7, the sheet size of the sheet Sh is as long as 700 mm, and the time Ta calculated by the equation 1 is longer than the response time Tb (600 ms) of the image reading unit 41. Therefore, even when the transport of the sheet Sh is performed at the fastest transport speed Sp1 at which the image reading unit 41 can read an image (image analysis), the temperature measurement of the sheet Sh by the temperature measurement unit 42 is accurately performed. It will be.

(4th control)
Next, control in the case where conveyance at the conveyance speed Sp2 is impossible (hereinafter, referred to as "fourth control") will be described. For example, when the sheet size of the sheet Sh is small, etc., there is also a possibility that the transport speed Sp2 calculated by the equation 2 is lower than the minimum linear velocity at which the transport path 21 can transport the sheet Sh. In such a case, the conveyance control unit 451 stops the driving of the conveyance path 21 by the sheet conveyance unit 44 while the temperature measurement unit 42 measures the temperature of the sheet Sh. Then, after the measurement of the sheet temperature by the temperature measurement unit 42 is completed, the conveyance of the sheet Sh in the conveyance path 21 is resumed.

(Fifth control)
In addition, after performing conveyance with the conveyance speed Sp1 for a time Tc (an example of the second time), by performing control for stopping conveyance for a time Td (hereinafter, referred to as “fifth control”), The sheet temperature can be measured at a position near the center of the sheet Sh rather than at the end face. The time Tc can be calculated by the following equation 4, and the time Td can be calculated by the following equation 5.

  Tc = ((Pt-Ps) / 2) / Sp1 Formula 4

  According to the equation 4, the time Tc is calculated by dividing the half distance of the distance between the image acquisition position Ps and the sheet temperature acquisition position Pt by the transport speed Sp1.

  Td = Tb−Tc formula 5

  According to the equation 5, the time Td is calculated by subtracting the time Tc calculated by the equation 4 from the response time Tb of the temperature measurement unit 42.

  A specific embodiment of the fifth control will be described with reference to FIG. FIG. 8 shows an operation diagram Dl1 of the front end of the sheet Sh and an operation diagram Dt1 of the rear end of the sheet. In the example shown in FIG. 8, the sheet size of the sheet Sh is 100 mm, the response time Tb of the image reading unit 41 is 600 ms, and the transport speed Sp1 is 1000 mm / s.

  In FIG. 8, when the first or second control (control to shift to the transport speed Sp2) is performed, the operation diagram Dl1 of the sheet front end of the sheet Sh and the operation of the sheet rear end in the sheet temperature measurement period The diagram Dt1 is indicated by a thick dashed-dotted line. The operation diagram Dl1 of the leading end of the sheet Sh and the operation diagram Dt1 of the sheet rear end in the sheet temperature measurement period in the case where the fourth control is performed are indicated by thick dashed lines. The conveyance of the sheet Sh is stopped after the sheet Sh is conveyed at the conveyance speed Sp1 for the time Tc calculated by the equation 4 above, whereby the central portion of the sheet Sh, not the sheet end face, reaches the sheet temperature measurement position Pt. At this point, the temperature of the sheet Sh is to be measured.

  By performing the fourth control, the temperature of the sheet Sh can be measured accurately even when the sheet size of the sheet Sh is small.

<Control Method for Color Correction by Image Forming Apparatus>
(Control method for color correction by the image forming apparatus)
Next, a method of color correction control by the image forming apparatus 1 of the present embodiment will be described. First, with reference to FIG. 9 to FIG. 11, a method of control for color correction by the image forming apparatus main body 10 constituting the image forming apparatus 1 of the present embodiment will be described. FIG. 9 is a flowchart showing the procedure of the color correction control method of the image forming apparatus main body 10. FIG. 10 is a process for calculating the sheet interval and the conveyance speed by the conveyance control unit 112 (see FIG. 3) of the image forming apparatus main body 10. Is a flowchart showing the procedure of FIG. 11 is an explanatory view showing a configuration example of a sheet interval and conveyance speed calculation table to which the conveyance control unit 112 refers in the sheet interval and conveyance speed calculation process.

  As shown in FIG. 9, when a job for performing color monitoring and correction (hereinafter, also simply referred to as “job”) is started, the conveyance control unit 112 of the image forming apparatus main body 10 calculates the sheet interval and conveyance speed. A process is performed (step S11). In the inter-sheet and transport speed calculation process of step S11, the inter-sheet interval Ty and the transport speed Sp1 are calculated. The details of the sheet interval and transport speed calculation process in step S11 will be described later with reference to FIG.

  Next, the transport control unit 112 feeds the next sheet Sh after waiting for the space between the sheet Tx and the previous sheet Sh calculated in step S11 to be wide (step S12). Next, the image forming unit 30 of the image forming apparatus main body 10 performs an image forming process, that is, a printing process (step S13). Next, the transport control unit 112 transports the sheet Sh to the post-processing device 40 at the transport speed Sp1 calculated in step S11 (step S14).

  Next, the control device 100 of the image forming apparatus main body 10 determines whether the job has ended (step S15). In step S15, when the control device 100 determines that the job is completed (when the determination in step S15 is YES), the control for color correction by the image forming apparatus main body 10 is completed.

  On the other hand, when the control device 100 determines that the job has not ended in step S15 (when the determination in step S15 is NO), the control device 100 receives the image reading result and the temperature measurement result from the post-processing device 40 It is determined whether or not (step S16). When it is determined in step S16 that the control device 100 has not received the image reading result and the temperature measurement result (when the determination in step S16 is NO), the control device 100 returns the process to step S11.

  On the other hand, when it is determined in step S16 that the image reading result and the temperature measurement result are received from the post-processing device 40 (when the determination in step S16 is YES), the control device 100 performs color correction based on each received result. Is determined (step S17). Whether or not the color correction is necessary is determined, for example, based on whether or not the chromaticity of the patch image read by the image reading unit 41 is within the range of a predetermined area. If it is determined in step S17 that color correction is required (if step S17 is a YES determination), the color correction unit 111 of the control device 100 performs color correction based on the image reading result and the temperature measurement result. (Step S18). On the other hand, when it is determined in step S17 that color correction is not necessary (when step S17 is NO), the control device 100 returns the process to step S11.

  Next, with reference to FIG. 10, the procedure for calculating the sheet interval and the conveyance speed in step S11 of FIG. 9 will be described. First, the conveyance control unit 112 of the image forming apparatus main body 10 refers to the sheet interval / conveyance speed calculation table based on the sheet size of the sheet Sh passing the image forming apparatus main body 10 and the number of monitoring patches. Ty and the transport speed Sp1 are calculated (step S21).

  The transport speed Sp1 is the fastest transport speed at which the image reading unit 41 can read and analyze the image, as described above. If the conveyance speed Sp1 is faster than the appropriate conveyance speed in accordance with the image reading cycle (sheets / second) by the image reading unit 41, the image area which can be read by the image reading unit 41 is reduced. On the other hand, if the transport speed is lower than the appropriate transport speed, a large amount of memory for storing the image is required. In the present embodiment, the transport speed Sp1 is set to an appropriate transport speed based on the image reading cycle determined by the hardware performance of the CCD and the like constituting the image reading unit 41.

  In calculating the transport speed Sp1, it is also necessary to consider the number of patches to be monitored. When the number of patches to be monitored is small, by increasing the patch image size (color patch area), an image area necessary for image analysis of each color can be secured even if the transport speed Sp1 is high. On the other hand, when the number of monitoring target patches is large, it is necessary to slow the transport speed Sp1 in order to acquire an image area necessary for image analysis of each color. Therefore, in the present embodiment, the item of the number of monitoring patches is also provided in the sheet interval / sheet conveyance speed calculation table to be referred to when calculating the conveyance speed Sp1.

  Here, with reference to FIG. 11, a configuration example of the sheet interval and conveyance speed calculation table will be described. The sheet interval and sheet conveyance speed calculation table illustrated in FIG. 11 includes “monitoring patch number”, “sheet size L”, “sheet conveyance speed Sp1 [mm / s]”, “sheet interval Ty [ms]”, and “patch image size” It consists of each item of. The sheet interval and sheet conveyance speed calculation table stores the number of monitoring patches, the sheet size L of the sheet Sh and the patch image size in association with the sheet conveyance speed Sp1 and the sheet interval Ty.

  According to the sheet interval and conveyance speed calculation table, when the number of monitoring patches is “1 to 2”, the sheet size L is 210 mm or more, and the patch image size is “large”, the conveyance speed Sp1 is It is set to "1000 mm / s". Further, the sheet interval Ty is set to “1.3333 × L + 99.333”. Also, for example, when the number of monitoring patches is "3 to 4" and the patch image size is "small", the transport speed Sp1 is set to "250 mm / s" and the sheet interval Ty is "250 ms". Set to If the number of monitored patches is as large as "5 to 8" and the sheet size L of the sheet Sh is less than 210 mm, it is considered that there is no space where the patch image can be printed on the sheet Sh. It has been done.

  Returning to FIG. 10, the description of the sheet interval and conveyance speed calculation process of step S11 of FIG. 9 will be continued. After the process of step S21, the conveyance control unit 112 of the image forming apparatus main body 10 adds the conveyance time corresponding to the increase by conveying the sheet Sh at the conveyance speed Sp2 to the sheet interval Ty calculated in step S21. , A new sheet interval Tx is calculated (step S22). The sheet interval Tx can be calculated by the following equation 6.

  Tx = Ty + (Tb-((Pt-Ps) / Sp1)) Formula 6

(Control method for color correction by post-processing device)
Next, with reference to FIG. 12 and FIG. 13, a control method for color correction by the post-processing device 40 constituting the image forming apparatus 1 of the present embodiment will be described. 12 and 13 are flowcharts showing the procedure of the color correction control method by the post-processing apparatus 40. As shown in FIG. 12, first, when a job for performing color monitoring and correction is started, the post-processing apparatus 40 receives the sheet Sh (step S31). Next, the transport control unit 451 of the post-processing device 40 controls the sheet transport unit 44 such that the sheet Sh is transported at the transport speed Sp1 (step S32).

  Next, the control unit 45 of the post-processing device 40 determines whether the leading end of the sheet Sh has reached the image acquisition position Ps (see FIG. 5 and the like) (step S33). When it is determined in step S33 that the leading end of the sheet Sh has not reached the image acquisition position Ps (when the determination in step S33 is NO), the control unit 45 repeats the determination in step S33. On the other hand, when it is determined in step S33 that the leading end of the sheet Sh has reached the image acquisition position Ps (when the determination in step S33 is YES), the image reading unit 41 of the post-processing device 40 forms on the sheet Sh. The reading of the selected patch image is started (step S34).

  Next, the control unit 45 determines whether the leading end of the sheet Sh has reached the sheet temperature measurement position Pt (see FIG. 5 and the like) (step S35). When it is determined in step S35 that the leading end of the sheet Sh has not reached the sheet temperature measurement position Pt (when the determination in step S35 is NO), the control unit 45 repeats the determination in step S35. On the other hand, when it is determined in step S35 that the leading end of the sheet Sh has reached the sheet temperature measurement position Pt (when the determination in step S35 is YES), the temperature measurement unit 42 of the post-processing device 40 determines the temperature of the sheet Sh The measurement of is started (step S36).

  Next, the control unit 45 determines whether the trailing edge of the sheet Sh has reached the image acquisition position Ps (step S37). When it is determined in step S37 that the rear end of the sheet Sh has not reached the image acquisition position Ps (when the determination in step S37 is NO), the control unit 45 repeats the determination in step S37. On the other hand, when it is determined in step S37 that the rear end of the sheet Sh has reached the image acquisition position Ps (when the determination in step S37 is YES), the image reading unit 41 ends the reading of the patch image of the sheet Sh. (Step S38). Next, the control unit 45 calculates the time Ta (step S39). The time Ta can be calculated using the equation 1 described above.

  The processes after step S39 will be described with reference to FIG. After calculating the time Ta in step S39, the control unit 45 determines whether the time Ta is equal to or longer than the response time Tb of the image reading unit 41 (step S41). When it is determined in step S41 that the time Ta is equal to or longer than the response time Tb of the image reading unit 41 (when the determination in step S41 is YES), the transport control unit 451 of the post-processing apparatus 40 operates the sheet Sh at the transport speed Sp1. Transport (step S42).

  Next, the control unit 45 of the post-processing device 40 determines whether the trailing end of the sheet Sh has reached the sheet temperature measurement position Pt (step S43). If it is determined in step S43 that the trailing end of the sheet has not reached the sheet temperature measurement position Pt (in the case of NO in step S43), the control unit 45 repeats the determination in step S43.

  On the other hand, when it is determined in step S43 that the rear end of the sheet Sh has reached the sheet temperature measurement position Pt (when the determination in step S43 is YES), the control unit 45 determines the temperature of the sheet Sh by the temperature measurement unit 42 The measurement is ended (step S44). Next, the control unit 45 of the post-processing apparatus 40 transmits the image reading result of the image reading unit 41 and the temperature measurement result of the temperature measuring unit 42 to the image forming apparatus main body 10 via the transmitting unit 43 (step S45).

  Next, the control unit 45 of the post-processing apparatus 40 determines whether the job for performing color monitoring and correction has ended (step S46). If it is determined in step S46 that the job has ended (if the determination in step S46 is YES), the post-processing apparatus 40 ends the color correction control. On the other hand, if it is determined in step S46 that the job has not ended (if NO in step S46), the control unit 45 returns the process to step S31 in FIG.

  For example, if the size of the sheet Sh is large and the time Ta is equal to or longer than the response time Tb of the temperature measurement unit 42, YES is determined in step S41, and the processes of steps S42 to S44 are performed. These processes correspond to the third control.

  When it is determined in step S41 that the time Ta is less than the response time Tb of the image reading unit 41 (when the determination in step S41 is NO), the control unit 45 of the post-processing device 40 calculates the transport speed Sp2. (Step S47). The transport speed Sp2 can be calculated by the above-mentioned equation 2. Next, the control unit 45 of the post-processing device 40 determines whether or not the transport speed Sp2 calculated in step S42 is equal to or higher than the lowest linear speed at which the sheet Sh can be transported (step S48).

  When it is determined in step S48 that the calculated transport speed Sp2 is equal to or higher than the minimum linear velocity of the sheet Sh (when the determination in step S48 is YES), the transport control unit 451 of the post-processing device 40 transports the sheet Sh. Control to carry at the speed Sp2 is performed (step S49). Next, the control unit 45 of the post-processing device 40 determines whether the trailing edge of the sheet Sh has reached the sheet temperature measurement position Pt (step S50). If it is determined in step S50 that the trailing edge of the sheet has not reached the sheet temperature measurement position Pt (in the case of NO in step S50), the control unit 45 repeats the determination of step S50.

  On the other hand, when it is determined in step S50 that the trailing end of the sheet has reached the sheet temperature measurement position Pt (when YES in step S50), the control unit 45 ends the temperature measurement of the sheet Sh by the temperature measurement unit 42. Let Further, the control unit 45 returns the transport speed of the sheet Sh to the transport speed Sp1 (step S51). After the process of step S51, the control unit 45 performs the process of step S45.

  The processes of steps S49 to S51 performed after the determination of YES in step S48 corresponds to the first or second control.

  If it is determined in step S48 that the calculated transport speed Sp2 is less than the lowest linear velocity capable of transporting the sheet Sh (in the case of NO in step S48), the transport control unit 451 of the post-processing device 40 determines the transport speed. Control to transport the sheet Sh by Sp1 is performed (step S52). Next, the control unit 45 of the post-processing device 40 determines whether or not the time Tc has passed after the conveyance of the sheet Sh at the conveyance speed Sp1 (step S53). The time Tc can be calculated using Equation 4 described above.

  When it is determined in step S53 that the time Tc has not elapsed (when the determination in step S53 is NO), the control unit 45 repeats the determination in step S53. On the other hand, when it is determined in step S53 that the time Tc has elapsed (when the determination in step S53 is YES), the conveyance control unit 451 performs control to stop the conveyance of the sheet Sh (step S54).

  Next, after the conveyance of the sheet Sh is stopped in step S54, the control unit 45 of the post-processing device 40 determines whether or not the time Td has elapsed (step S55). The time Td can be calculated using Equation 5 described above. When it is determined in step S55 that the time Td has not elapsed (when the determination in step S55 is NO), the control unit 45 repeats the determination in step S55. On the other hand, when it is determined in step S55 that the time Td has elapsed (when the determination in step S55 is YES), the control unit 45 of the post-processing device 40 ends the measurement of the sheet temperature by the temperature measurement unit 42 and transports The conveyance of the sheet Sh at the speed Sp1 is resumed (step S56). After the process of step S56, the control unit 45 performs the process of step S45.

  The processes of steps S52 to S56, which are performed after the determination of NO in step S48, corresponds to the fifth control.

  In the embodiment described above, the transport speed of the sheet Sh is controlled in accordance with the arrangement relationship between the image reading unit 41 and the temperature measurement unit 42 and the sheet size of the sheet Sh. Therefore, according to the present embodiment, it is possible to perform appropriate color correction in accordance with the properly measured paper temperature without unnecessarily reducing the productivity of the image forming apparatus 1 (while maintaining it as much as possible). become.

  Further, in the above-described embodiment, the conveyance speed of the sheet Sh is calculated using the information of the image reading position Ps and the sheet temperature measurement position Pt, and the conveyance control based on the calculated conveyance speed is performed. Therefore, in various image forming apparatuses in which the arrangement relationship between the image reading position Ps and the sheet temperature measurement position Pt is different, appropriate conveyance control for realizing appropriate color correction in accordance with the sheet temperature appropriately measured It can be implemented.

  Further, in the above-described embodiment, the sheet is conveyed at the conveyance speed Sp1 which is the fastest conveyance speed at which the image reading unit can read the image until the trailing edge of the sheet Sh reaches the image acquisition position Ps. . Therefore, the productivity of the image forming apparatus 1 in the meantime is maintained.

  Further, in the above-described embodiment, the temperature measurement unit 42 measures when the sheet rear end of the sheet Sh passes the image acquisition position Ps and the sheet rear end of the sheet Sh reaches the sheet temperature measurement position Pt. The sheet Sh is transported at a transport speed Sp2 that is a speed suitable for temperature measurement. Therefore, the temperature of the sheet Sh is also properly measured. In addition, since the shift to the transport speed Sp2 is started after the trailing edge of the sheet Sh passes the image acquisition position Ps, the transport speed is fixed before the front end of the sheet reaches the image acquisition position Ps. It is not necessary to decelerate from (conveying speed Sp1) to a speed at which the temperature of the sheet can be measured (conveying speed Sp2). Therefore, according to the present embodiment, even if the distance from the fixing unit to the image reading unit in the image forming apparatus is short, the temperature measurement of the sheet Sh can be accurately performed.

  Further, in the above-described embodiment, the conveyance control unit 451 of the post-processing device 40 calculates the conveyance speed Sp2 using the equation 2. That is, the conveyance control unit 451 first calculates the time Ta by dividing the distance between the image acquisition position Ps and the sheet temperature acquisition position Pt by the conveyance speed Sp1. Then, the conveyance speed Sp2 is calculated by dividing the distance between the image acquisition position Ps and the sheet temperature acquisition position Pt by the time obtained by subtracting the time Ta from the response time Tb of the temperature measurement unit 42. That is, in the present embodiment, the sheet Sh can be held at the sheet temperature measurement position Pt while the sheet Sh is at the sheet temperature measurement position Pt until the temperature measurement time of the temperature measurement unit 42 elapses after the time Ta elapses. Is transported. Therefore, according to the present embodiment, the temperature measurement of the sheet Sh is accurately performed.

  Further, in the above-described embodiment, the conveyance control unit 451 of the post-processing device 40 returns the conveyance speed of the sheet Sh to the conveyance speed Sp1 after the sheet rear end of the sheet Sh passes the sheet temperature measurement position Pt. Therefore, according to the present embodiment, the productivity of the image forming apparatus 1 is not unnecessarily reduced.

  Further, in the above-described embodiment, when a plurality of sheets are continuously transported on the transport path 21, the transport control unit 451 performs transport control to realize the sheet interval Tx calculated by Equation 3 (above). Perform the second control). That is, the conveyance control unit 451 calculates the sheet interval Tx by adding the time obtained by subtracting the time Ta from the response time Tb of the temperature measurement unit 42 to the normal sheet interval Ty, and after feeding the preceding sheet Sh, After waiting for a time corresponding to the sheet interval Tx, control is performed to feed the next sheet Sh. Therefore, according to the present embodiment, even when a plurality of sheets Sh are continuously printed, the sheets Sh before and after being transported on the transport path 21 will not be hit. In addition, it is possible to ensure both the productivity of the image forming apparatus 1 and the appropriate color correction according to the sheet temperature appropriately measured.

  Further, in the above-described embodiment, when the time Ta is equal to or longer than the response time Tb of the temperature measurement unit 42, the shift to the transport speed Sp2 is not performed (the third control). That is, when the sheet size of the sheet Sh is large and it is expected to secure a sufficient time for the temperature measurement by the temperature measurement unit 42, the conveyance at the conveyance speed Sp1 is performed, so the productivity of the image forming apparatus 1 is Is maintained.

  Further, in the above-described embodiment, when the transport speed Sp2 is lower than the lowest linear velocity capable of transporting the sheet Sh, the transport control unit 451 stops the transport of the sheet Sh. Then, after the measurement time of the temperature of the sheet Sh by the temperature measurement unit 42 elapses, the conveyance of the sheet Sh is resumed (the fourth control). Therefore, according to the present embodiment, the temperature of the sheet Sh can be accurately measured even when, for example, the sheet size of the sheet Sh is small.

  Further, in addition to the fourth control, the sheet Sh is conveyed at the conveyance speed Sp1 for the time Tc calculated by the equation 4 above, and the conveyance of the sheet Sh is stopped for the time Td calculated by the equation 5 above. By performing the fifth control, temperature measurement near the center of the sheet Sh becomes possible.

  The present invention is not limited to the embodiment described above, and it is needless to say that various other applications and modifications can be taken without departing from the scope of the present invention described in the claims. .

  In the embodiment described above, although the case where the transport control unit 451 of the post-processing apparatus 40 returns the transport speed to the transport speed Sp1 after the end of the transport at the transport speed Sp2 is described as an example, the present invention is limited thereto I will not. For example, after the end of the conveyance at the conveyance speed Sp2, the sheet Sh may be conveyed at a speed higher than the conveyance speed Sp1 or a speed lower than the conveyance speed Sp1.

  In the above-described embodiment, the conveyance control unit 451 of the post-processing apparatus 40 performs all of the first to fifth controls, but the present invention is not limited to this. Control may be performed by combining any one or some of the first to fifth controls.

  In the above-described embodiment, the conveyance control unit 112 of the image forming apparatus main body 10 and the conveyance control unit 451 of the post-processing apparatus 40 individually perform conveyance control, but the present invention is not limited thereto. It is not limited. For example, either one of the conveyance control unit 112 of the image forming apparatus main body 10 or the conveyance control unit 451 of the post-processing apparatus 40 may be configured to perform conveyance control of the entire image forming apparatus 1.

  Further, in the embodiment described above, the case where the transport control unit 451 of the post-processing apparatus 40 performs the first to fifth controls is described as an example, but the present invention is not limited to this. For example, the first to fifth controls may be performed in the image forming apparatus main body 10 instead of the post-processing apparatus 40.

  In the embodiment described above, the image forming apparatus 1 including the image forming apparatus main body 10 and the post-processing apparatus 40 performs the color correction control, but the present invention is not limited to this. For example, the present invention can be applied to an image forming apparatus that does not include the post-processing apparatus 40, an image forming apparatus that includes multiple post-processing apparatuses 40, and the like.

  Also, for example, the above-described embodiment is a detailed and specific description of the configuration of the apparatus (image forming apparatus) in order to explain the present invention in an easy-to-understand manner, and is necessarily limited to those having all the configurations described. It is not something to be done.

  In addition, each of the configurations, functions, processing procedures, and the like described above may be realized by hardware, for example, by designing part or all of them with an integrated circuit. Further, each configuration, function, etc. described above may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as a program, a table, and a file for realizing each function can be placed in a memory, a hard disk, a recording device such as a solid state drive (SSD), or a recording medium such as an IC card, an SD card, or a DVD.

  In addition, control lines and information lines shown by solid lines or arrows in FIGS. 3 and 4 indicate what is considered necessary for explanation, and it is assumed that all control lines and information lines on products are shown. Not exclusively. In practice, almost all configurations may be considered to be mutually connected.

  Furthermore, in the present specification, processing procedures describing time-series processing are parallel or individual processing not necessarily performed chronologically, as well as processing performed chronologically in the order described. Processing (eg, parallel processing or processing by an object).

  DESCRIPTION OF SYMBOLS 1 ... image forming apparatus, 10 ... image forming apparatus main body, 11 ... image input part, 12 ... automatic document feeder, 13 ... operation display part, 20A ... paper feed tray, 21 ... conveyance path, 30 ... image forming part, 41: image reading unit 42: temperature measurement unit 43: transmission unit 44: paper conveyance unit 45: control unit 112: conveyance control unit 451: conveyance control unit

Claims (24)

An image forming unit that forms an image on a sheet;
An image reading unit configured to form the image in the image forming unit and read a sheet surface of the sheet conveyed at a first conveyance speed ;
A temperature measurement unit that measures the temperature of the sheet on which the reading of the sheet has been performed by the image reading unit ;
A color correction unit that corrects the color of the image formed by the image forming unit based on the image on the sheet read by the image reading unit and the temperature of the sheet measured by the temperature measurement unit;
A conveyance control unit that performs sheet conveyance control to set a conveyance speed at a sheet temperature measurement position of the temperature measurement unit to a second conveyance speed that is lower than the first conveyance speed for a part of the sheet ; apparatus. The transport control unit
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. The image forming apparatus according to claim 1 , wherein, in some cases, the transport speed at the sheet temperature measurement position for all the sheets is the first transport speed . The transfer control unit, until the paper trailing edge of the sheet conveyed the conveying path reaches the image acquiring position for the image reading unit, conveys the sheet at the first transport speed, the paper claim paper trailing edge of the transported between the through the image obtaining positions until the paper trailing end of the sheet reaches before Symbol for feeding temperature measuring position, the paper in front Stories second transport speed The image forming apparatus according to 1 or 2 . The image forming apparatus according to any one of claims 1 to 3 , wherein the first conveyance speed is the fastest conveyance speed at which the image reading unit can read an image. 5. The conveyance control unit according to any one of claims 1 to 4 , wherein the conveyance control unit returns the conveyance speed of the sheet to the first conveyance speed after the sheet rear end of the sheet passes the sheet temperature measurement position. Image forming apparatus. For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. An image forming apparatus according to any one of claims 1 to 5 . When a plurality of sheets of paper are continuously conveyed on the conveyance path,
A second one between the plurality of sheets when the conveyance control unit sets the conveyance speed at the sheet temperature measurement position to a second conveyance speed that is lower than the first conveyance speed for a part of the sheets. The first sheet interval, which is the sheet interval of the plurality of sheets when the conveyance control unit sets the conveyance speed at the sheet temperature measurement position to the first conveyance speed, for all the sheets. Too long,
When the conveyance control unit sets the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed for a part of the sheets, a time corresponding to the second sheet interval The image forming apparatus according to any one of claims 1 to 6 , wherein control to feed the next sheet is performed after waiting for a minute . The image forming apparatus according to any one of claims 1 to 7 , wherein
An image forming apparatus main body including the image forming unit, the color correction unit, and the conveyance control unit ;
An image forming apparatus including the image reading unit and a temperature measuring unit . The image forming apparatus according to any one of claims 1 to 7, wherein
An image forming apparatus main body having the image forming unit and the color correction unit;
An image forming apparatus, comprising: a post-processing apparatus having the image reading unit, a temperature measuring unit, and the conveyance control unit. Forming an image on a sheet of paper;
A procedure in which the image reading unit reads the paper surface of the sheet , the image being formed and being conveyed at a first conveyance speed ;
Measuring the temperature of the sheet on which the reading of the sheet has been performed by the image reading unit using a temperature measuring unit;
Correcting the color of the image to be formed on the basis of the image on the sheet on which the reading has been performed and the measured temperature of the sheet;
A procedure for performing sheet conveyance control for setting the conveyance speed at the sheet temperature measurement position of the temperature measurement unit to a second conveyance speed lower than the first conveyance speed for a part of the sheet;
A program to make a computer run. In the procedure for performing the sheet conveyance control,
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. in some cases, the program according to claim 1 0 to all the said sheet temperature measuring the transport speed at the location the first conveying speed of the paper. For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. The program described in 10 or 11. An image forming unit that forms an image on a sheet;
An image reading unit configured to form the image in the image forming unit and read a sheet surface of the sheet conveyed at a first conveyance speed ;
A temperature measurement unit that measures the temperature of the sheet on which the reading of the sheet has been performed by the image reading unit ;
A color correction unit that corrects the color of the image formed by the image forming unit based on the image on the sheet read by the image reading unit and the temperature of the sheet measured by the temperature measurement unit;
In an image forming apparatus including a control unit,
A method of performing sheet conveyance control in which a conveyance speed at a sheet temperature measurement position of the temperature measurement unit is set to a second conveyance speed lower than the first conveyance speed for a part of the sheet. In the sheet conveyance control,
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. in some cases, a method of performing sheet conveyance control according to the conveying speed in the sheet temperature measurement positions for all of the paper to claims 1 to 3, the first transport speed. For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. A method of performing sheet conveyance control according to 13 or 14. An image reading unit that forms an image by the image forming apparatus main body and reads a sheet surface of a sheet conveyed at a first conveyance speed ;
The temperature of the sheet on which the paper reading has been performed by the image reading unit, which is used to perform color correction on the image forming apparatus main body together with the image on the paper read by the image reading unit. A temperature measurement unit that measures the temperature;
A transmitting unit that transmits the image read by the image reading unit and the temperature measured by the temperature measuring unit to a color correction unit of the image forming apparatus main body;
A conveyance control unit that performs sheet conveyance control to set the conveyance speed at the sheet temperature measurement position of the temperature measurement unit to a second conveyance speed that is lower than the first conveyance speed for a part of the sheets; apparatus. The transport control unit
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. 17. The post-processing apparatus according to claim 16 , wherein, in some cases, the transport speed at the sheet temperature measurement position for all of the sheets is the first transport speed . For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. The post-processing apparatus as described in 16 or 17. A procedure in which an image is formed by the image forming apparatus main body and an image reading unit reads the sheet surface of the sheet transported at a first transport speed ;
The temperature of the sheet on which the paper reading has been performed by the image reading unit, which is used to perform color correction on the image forming apparatus main body together with the image on the paper read by the image reading unit. A procedure of measuring the temperature by the temperature measuring unit;
Transmitting the image read by the image reading unit and the temperature measured by the temperature measurement unit to a color correction unit of the image forming apparatus main body;
A procedure for performing sheet conveyance control for setting the conveyance speed at the sheet temperature measurement position of the temperature measurement unit to a second conveyance speed lower than the first conveyance speed for a part of the sheet;
A program to make a computer run. In the procedure for performing the sheet conveyance control,
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. 20. The program according to claim 19 , wherein, in some cases, the transport speed at the sheet temperature measurement position for all the sheets is the first transport speed . For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. The program described in 19 or 20. An image reading unit configured to form the image by an image forming apparatus main body and read the sheet surface of the sheet conveyed at a first conveyance speed ;
The temperature of the sheet on which the paper reading has been performed by the image reading unit, which is used to perform color correction on the image forming apparatus main body together with the image on the paper read by the image reading unit. A temperature measurement unit that measures the temperature by the temperature measurement unit;
A transmitting unit that transmits the image read by the image reading unit and the temperature measured by the temperature measuring unit to a color correction unit of the image forming apparatus main body;
A post-processing apparatus including a control unit;
A method of performing sheet conveyance control in which a conveyance speed at a sheet temperature measurement position of the temperature measurement unit is set to a second conveyance speed lower than the first conveyance speed for a part of the sheet. In the sheet conveyance control,
When the sheet size of the sheet is a first size in which the temperature measuring unit can not measure the temperature of the sheet when the sheet is conveyed at the first conveyance speed, a part of the sheet For the sheet temperature measurement position as a second conveyance speed lower than the first conveyance speed,
The sheet size of the sheet is a second size larger than the first size which can ensure time for the temperature measuring unit to measure the temperature of the sheet when the sheet is transported at the first transport speed. 22. The method according to claim 21, wherein the transport speed at the sheet temperature measurement position for all the sheets is the first transport speed . For the part of the sheet, setting the conveyance speed at the sheet temperature measurement position to a second conveyance speed lower than the first conveyance speed includes stopping the sheet at the sheet temperature measurement position. 22. A method of performing sheet conveyance control according to 22 or 23.

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