Rigidity measurement device and image forming system

Abstract

To provide a rigidity measurement device capable of measuring rigidity of a recording material such as a sheet with high accuracy, and to provide an image forming system.SOLUTION: A rigidity information acquisition device includes: a holding member for holding a recording material in such a manner that a recording surface of the recording material becomes substantially in parallel with a vertical direction; a pressing part for pressing the recording surface of the recording material held by the holding member; and a rigidity acquisition part for measuring a reaction force of the recording material when being pressed by the pressing part, and for acquiring the measured reaction force as the rigidity of the recording material. Then, a portion for holding the recording material of the holding member is formed by a material having the same hardness.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a stiffness measuring device and an image forming system. [Background technology]

[0002] In an image forming apparatus that forms an image on a recording medium, such as paper, there is known a technique for detecting the stiffness of the recording material, such as paper, and setting various control parameters based on the detection results. For example, stiffness data of the recording material is fed back to transfer conditions. Patent Document 1 describes a technique for detecting the stiffness of paper. The image forming apparatus described in Patent Document 1 presses the paper against a lever during transportation, and detects the amount of displacement of the lever at that time as the stiffness of the paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-049178 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the image forming device described in Patent Document 1 holds the paper in a predetermined position while it is being transported horizontally and measures the stiffness of the paper. Therefore, the stiffness measurement result includes the effect of gravity acting on the paper. Therefore, the image forming device described in Patent Document 1 has a problem in that it cannot accurately measure the stiffness of the paper.

[0005] One way to cancel the effect of gravity is, for example, to lift the paper by the amount that has sagged due to gravity. However, it is difficult to precisely lift the paper by the amount that has sagged due to gravity. Also, the longer the distance from the part that holds the paper to the lever, the greater the effect of gravity becomes, so it is difficult to accurately grasp the effect of gravity required to cancel it.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a stiffness measuring device and an image forming system capable of measuring the stiffness of a recording material such as paper with high accuracy. [Means for solving the problem]

[0007] In order to achieve at least one of the above-mentioned objects, a stiffness measuring device reflecting one aspect of the present invention includes a clamping member, a pressing unit, and a stiffness acquiring unit. The clamping members clamp the recording material so that the recording surface of the recording material is approximately parallel to the vertical direction. The pressing unit presses the recording surface of the recording material clamped by the clamping members. The stiffness acquiring unit measures the reaction force of the recording material when pressed by the pressing unit, and acquires the measured reaction force as the stiffness of the recording material. The portions of the clamping members that clamp the recording material are formed of materials having the same hardness.

[0008] An image forming system according to one aspect of the present invention includes an image forming unit that forms an image on a recording material, a recording material container capable of containing the recording material, and a recording material transport path provided between the recording material container and the image forming unit. The image forming system further includes the above-mentioned stiffness measuring device that is installed on the recording material transport path and measures stiffness of the recording material, and a control unit that sets image formation parameters in accordance with the measurement results of the stiffness measuring device. Effect of the Invention

[0009] According to the stiffness measuring device and image forming system having the above configuration, the stiffness of the recording material can be measured with high accuracy. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an image forming system according to an embodiment. [Diagram 2] FIG. 2 is a system block diagram of an image forming system according to an embodiment. [Diagram 3] FIG. 3 is a functional block diagram of a control unit in the image forming system according to an embodiment. [Figure 4] FIG. 4 is a diagram showing a schematic configuration of a stiffness measuring device according to an embodiment. [Diagram 5] FIG. 5 is a view of a pair of support rollers of the stiffness measuring device as viewed from above. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a control system of a stiffness measuring device according to an embodiment. [Figure 7] FIG. 7 is a diagram illustrating a plurality of clamping members of the stiffness measuring device. [Figure 8] FIG. 8 is a diagram showing a state in which the pressing portion of the stiffness measuring device presses the recording material. [Figure 9] 9A and 9B are diagrams showing a state in which the pressing portion presses the recording material when the clamping force of the clamping members in the stiffness measuring device is insufficient. [Figure 10] FIG. 10 is a diagram showing a state in which the pressing portion presses the recording material when the distance from the clamping member in the stiffness measuring device to the lower end of the recording material is equal to or greater than a predetermined distance. [Figure 11] FIG. 11 is a diagram for explaining the clamping force of a plurality of clamping members in a stiffness measuring device. [Figure 12] FIG. 11 is a flowchart showing the procedure of the parameter setting process of the image forming system according to the first embodiment of the present invention. [Figure 13] FIG. 13 is a diagram showing a modified example of the clamping member in the stiffness measuring device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, substantially the same components are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0012] [Image formation system configuration] First, the configuration of an image forming system according to an embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of an image forming system according to an embodiment.

[0013] As shown in FIG. 1, the image forming system 10 includes a recording material supplying device 100, a recording material conveying device 400, an image forming device 200, and a post-processing device 300.

[0014] When an image is formed on a recording material S in the image forming system 10, first, the recording material S is supplied from the recording material supply device 100 to the recording material conveying device 400. Then, the recording material conveying device 400 conveys the recording material S to the image forming apparatus 200. The recording material conveying device 400 includes a stiffness measuring device 410 that measures stiffness of the recording material S.

[0015] Next, the image forming apparatus 200 forms an image on the recording material S supplied from the recording material conveying apparatus 400. Then, the image forming apparatus 200 sends the recording material S on which the image has been formed to the post-processing apparatus 300. The post-processing apparatus 300 performs a predetermined post-processing on the recording material S on which the image has been formed. Thereafter, the post-processing apparatus 300 ejects the recording material S.

[0016] [Recording material supply device] The recording material supplying device 100 stores a recording material S for image formation. When the recording material supplying device 100 receives an image formation job from a control unit 90 (described later) of the image forming system 10, the recording material supplying device 100 supplies the recording material S corresponding to the image formation job to the recording material conveying device 400. The recording material supplying device 100 includes a conveying unit 50 and a recording material supplying unit 70.

[0017] The recording material supply unit 70 includes a plurality of recording material storage units. The recording material storage units store recording materials S of different types and sizes, respectively. In this embodiment, the recording material S is a recording medium on which an image is formed, and is, for example, paper. The recording material S may be something other than paper, so long as the stiffness of the recording material S can be measured.

[0018] The conveying section 50 includes a plurality of take-out rollers that take out the recording material S from the recording material supplying section 70, and a plurality of conveying rollers 54. In Fig. 1, the plurality of take-out rollers are omitted. The plurality of conveying rollers 54 are disposed on a predetermined recording material conveying path. The plurality of conveying rollers 54 convey the recording material S taken out from the recording material supplying section 70 to the recording material conveying device 400 one sheet at a time.

[0019] [Recording material transport device] The recording material conveying device 400 includes an entrance 55 , a first conveying section 51 , a second conveying section 52 , a third conveying section 53 , a discharge section 56 , an exit 57 , and a stiffness measuring device 410 .

[0020] The carry-in entrance 55 carries in the recording material S supplied from the recording material supplying device 100. The first conveying section 51, the second conveying section 52, and the third conveying section 53 convey the recording material S carried in from the carry-in entrance 55 to the discharge section 56 or the discharge outlet 57. The first conveying section 51, the second conveying section 52, and the third conveying section 53 correspond to the recording material conveying section according to the present invention. The first conveying section 51, the second conveying section 52, and the third conveying section 53 each include a plurality of conveying rollers 54 for conveying the recording material S.

[0021] The recording material conveying device 400 has a branching portion 58 that branches the conveying path of the recording material S. The recording material conveying device 400 has a first conveying path 41 located upstream of the branching portion 58 in the recording material conveying direction, and a second conveying path 42 and a third conveying path 43 located downstream of the branching portion 58 in the recording material conveying direction.

[0022] The first transport path 41 is a path from the entrance 55 to the branching section 58. The first transport section 51 is disposed on the first transport path 41. The first transport section 51 transports the recording material S along the first transport path 41. The recording material S transported along the first transport path 41 is guided by the branching section 58 to the second transport path 42 or the third transport path 43.

[0023] The second transport path 42 is a path from the branching portion 58 to the discharge portion 56. The second transport portion 52 is disposed on the second transport path 42. The second transport portion 52 transports the recording material S along the second transport path 42. The recording material S transported along the second transport path 42 is discharged from the discharge portion 56.

[0024] The third transport path 43 is a path from the branching portion 58 to the discharge outlet 57. The third transport section 53 is disposed on the third transport path 43. The third transport section 53 transports the recording material S along the third transport path 43. The recording material S transported along the third transport path 43 is discharged from the discharge outlet 57. The recording material S discharged from the discharge outlet 57 is supplied to the image forming apparatus 200.

[0025] The stiffness measuring device 410 is disposed on the second transport path 42. The stiffness measuring device 410 is a device that measures the stiffness of the recording material S. The stiffness of the recording material S is an index that indicates the resistance when the recording material S is bent, and can be expressed using various physical quantities. The stiffness measuring device 410 measures the stiffness of the recording material S whose transport has been stopped midway along the second transport path 42. Hereinafter, the position at which the stiffness of the recording material S is measured is referred to as the "stiffness measurement position." The stiffness measurement position corresponds to a predetermined position according to the present invention.

[0026] [Image forming device] The image forming apparatus 200 includes an operation display unit 220 , a scanner 230 , an image forming unit 240 , and a conveying unit 250 .

[0027] The operation display unit 220 includes an operation unit and a display unit. The display unit is, for example, a display device such as an LCD (Liquid Crystal Display). The display unit displays various screens according to instructions of a display signal input from a control unit 90 (see FIG. 2) described later. The operation unit includes a touch panel formed so as to cover the display screen of the display unit, and various operation buttons such as numeric buttons and a start button. The operation unit accepts operation instructions from a user. The operation unit outputs an operation signal based on the user's operation to the control unit 90 described later.

[0028] The scanner 230 includes an automatic document feeder called an ADF (Auto Document Feeder) and an original image scanning device, which is a scanner. The automatic document feeder conveys an original placed on a document tray by a conveying mechanism and sends it to the original image scanning device. The original image scanning device optically scans an original conveyed onto a contact glass by the automatic document feeder or an original placed on the contact glass by a user, and reads an image of the original by forming an image of reflected light from the original on a light receiving surface of a CCD (Charge Coupled Device) sensor or the like. The scanner 230 generates image data based on the reading result by the original image scanning device.

[0029] The image forming section 240 forms an image on the recording material S based on image data. The image forming section 240 includes photoconductor drums 241Y, 241M, 241C, and 241K corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K), charging sections 242Y, 242M, 242C, and 242K, exposure sections 243Y, 243M, 243C, and 243K, developing sections 244Y, 244M, 244C, and 244K, and primary transfer rollers 245Y, 245M, 245C, and 245K. The image forming section 240 also includes an intermediate transfer belt 246, a secondary transfer roller 247, and a fixing section 248.

[0030] Hereinafter, the photoconductor drums 241Y, 241M, 241C, and 241K will be collectively referred to as "photoconductor drum 241." The charging sections 242Y, 242M, 242C, and 242K will be collectively referred to as "charging section 242," and the exposure sections 243Y, 243M, 243C, and 243K will be collectively referred to as "exposure section 243." Furthermore, the developing sections 244Y, 244M, 244C, and 244K will be collectively referred to as "developing section 244," and the primary transfer rollers 245Y, 245M, 245C, and 245K will be collectively referred to as "primary transfer roller 245."

[0031] Photoconductor drum 241 is an image carrier that carries a toner image. Photoconductor drum 241 rotates as driven by a photoconductor drive motor (not shown). Around photoconductor drum 241, charging section 242, exposure section 243, and development section 244 are arranged in this order from upstream to downstream in the rotation direction of photoconductor drum 241. Charging section 242 uniformly charges photoconductor drum 241.

[0032] The exposure unit 243 has a laser light source, a polygon mirror, a lens, etc. The exposure unit 243 scans and exposes the surface of the photoconductor drum 241 with a laser beam to form an electrostatic latent image. The scanning and exposure by the exposure unit 243 is performed based on image data read by the scanner 230 or image data received from an external device.

[0033] Developing unit 244 develops the electrostatic latent image formed on photoconductor drum 241 by attaching toner of each color to the electrostatic latent image formed on photoconductor drum 241. As a result, a toner image is formed on the image carrying surface of photoconductor drum 241. That is, a yellow toner image is formed on the image carrying surface of photoconductor drum 241Y. A magenta toner image is formed on the image carrying surface of photoconductor drum 241M. A cyan toner image is formed on the image carrying surface of photoconductor drum 241C. A black toner image is formed on the image carrying surface of photoconductor drum 241K.

[0034] The intermediate transfer belt 246 is looped around a plurality of belt support rollers. A primary transfer roller 245, a secondary transfer roller 247, a discharging roller (not shown), and a cleaning unit 249 are arranged on the movement path of the intermediate transfer belt 246.

[0035] The outer peripheral surface of the intermediate transfer belt 246 serves as an image bearing surface. The outer peripheral surface of the intermediate transfer belt 246 is in contact with the outer peripheral surface of the photosensitive drum 241. The intermediate transfer belt 246 rotates in the opposite direction to the rotation of the photosensitive drum 241. Specifically, the photosensitive drum 241 rotates in the counterclockwise direction in FIG. 1, and the intermediate transfer belt 246 rotates in the clockwise direction in FIG. 1.

[0036] The primary transfer roller 245 is disposed at a position facing the photoconductor drum 241. The primary transfer roller 245 is disposed on the inner circumferential side of the intermediate transfer belt 246, and sandwiches the intermediate transfer belt 246 between the primary transfer roller 245 and the opposing photoconductor drum 241.

[0037] The primary transfer roller 245 transfers the toner adhering to the image bearing surface of the photoconductor drum 241 to the image bearing surface of the intermediate transfer belt 246 by applying a charge of the opposite polarity to that of the toner to the intermediate transfer belt 246. As a result, a color toner image in which four color toner images are superimposed is formed on the image bearing surface of the intermediate transfer belt 246.

[0038] The secondary transfer roller 247 transfers the color toner image on the image carrying surface of the intermediate transfer belt 246 all at once onto one recording surface of the recording material S. The secondary transfer roller 247 and the belt support roller sandwich the intermediate transfer belt 246. The position where the secondary transfer roller 247 and the belt support roller face each other is a transfer position where the toner image transferred onto the image carrying surface of the intermediate transfer belt 246 is transferred onto the recording material S.

[0039] The cleaning unit 249 is disposed upstream of the primary transfer roller 245 and downstream of a discharging roller (not shown) in the rotation direction of the intermediate transfer belt 246. The cleaning unit 249 removes toner remaining on the image bearing surface of the intermediate transfer belt 246.

[0040] The fixing section 248 includes a fixing roller 248a and a pressure roller 248b. The fixing roller 248a has a built-in heater. The pressure roller 248b is pressed against the fixing roller 248a. As a result, the fixing roller 248a and the pressure roller 248b are pressed against each other, and a fixing nip portion is formed at this pressed portion. The recording material S is heated and pressurized when passing through the fixing nip portion. As a result, the toner image transferred to the recording material S is fixed.

[0041] The conveying section 250 includes a plurality of conveying rollers 54 for conveying the recording material S along a predetermined conveying path. The conveying section 250 conveys the recording material S supplied from the recording material conveying device 400 to a transfer position. The conveying section 250 also conveys the recording material S after image formation to the post-processing device 300.

[0042] [Post-processing device] The recording material S on which the image is formed by the image forming apparatus 200 is conveyed into the post-processing device 300. The post-processing device 300 includes a plurality of post-processing units, a conveying section 350, a discharge section 351, and a paper discharge tray 352.

[0043] When the post-processing device 300 receives a post-processing job from the control unit 90 described later, the post-processing device 300 executes a predetermined post-processing in a post-processing unit specified by the post-processing job. Examples of post-processing include perforation, folding, foil stamping, binding, cutting, stapling, gluing, and stitching.

[0044] The conveying section 350 includes a plurality of conveying rollers (not shown) for conveying the recording material S along a predetermined conveying path. The conveying section 350 conveys the recording material S supplied from the image forming apparatus 200 to a post-processing unit corresponding to the type of post-processing to be executed. The conveying section 350 also conveys the recording material S after the post-processing and discharges it from the discharge section 351. The recording material S discharged from the discharge section 351 is placed on the paper discharge tray 352.

[0045] [System block diagram] Next, an example of the configuration of a control system of the image forming system 10 will be described with reference to FIG. FIG. 2 is a system block diagram of the image forming system 10. As shown in FIG.

[0046] 2, the image forming system 10 includes a control unit 90, a storage unit 98, a communication unit 99, an operation display unit 220, a scanner 230, an image processing unit 80, a recording material supply unit 70, an image forming unit 240, conveying units 51, 52, 53, 250, 350, and a stiffness measuring device 410. Note that in the following, descriptions of components that overlap with the description of the image forming system 10 shown in FIG. 1 will be omitted.

[0047] The control unit 90 is composed of, for example, a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, and a RAM (Random Access Memory) 93. The various functions of the control unit 90 are realized by the CPU 91 executing a predetermined processing program stored in the ROM 92. The various functions of the control unit 90 include, for example, drive control of the recording material supply unit 70, drive control of the conveying units 50, 51, 52, 53, 250, and 350, and each operation control related to image formation by the image forming unit 240.

[0048] The ROM 92 stores various processing programs for controlling each part of the image forming system 10, parameters and table data required for executing the programs, various files, etc. The ROM 92 is used as an example of a computer-readable non-transitory recording medium that stores the programs executed by the CPU 91. Therefore, the programs are permanently stored in the ROM 92.

[0049] The RAM 93 is, for example, a volatile semiconductor memory. The RAM 93 forms a work area for temporarily storing various processing programs, input or output data, parameters, and the like read from the ROM 92 during various processes executed and controlled by the CPU 91.

[0050] The storage unit 98 stores, for example, image data received from an external device, etc. The storage unit 98 also stores various processing programs executed by the CPU 91, information on the processing functions of the device itself required for executing the programs, image data read by the scanner 230, image data input from a client device (not shown) or the like, stiffness information of the recording material S acquired by the stiffness measuring device 410, etc. The storage unit 98 is, for example, a non-volatile memory such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory.

[0051] The communication unit 99 includes a NIC (Network Interface Card), a modem, and the like. The communication unit 99 connects the recording material supplying device 100, the recording material conveying device 400, the image forming device 200, the post-processing device 300, and the stiffness measuring device 410 to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network). The communication unit 99 transmits various data to an external information device. The communication unit 99 also receives various data from the external information device. The external information device is, for example, a client device.

[0052] As described above, the operation display unit 220 functions as a display unit and an operation unit. The display unit displays various operation screens in accordance with a display control signal input from the control unit 90. The operation unit accepts various input operations by the user and outputs operation signals corresponding to the various input operations to the control unit 90.

[0053] The scanner 230 outputs the read analog image signal to the image processing unit 80 .

[0054] The image processing unit 80 has a circuit for analog-to-digital conversion and a circuit for digital image processing. The image processing unit 80 performs A / D conversion processing on the analog image signal supplied from the scanner 230 to generate digital image data. The image processing unit 80 also analyzes a print job acquired from an external information device, and rasterizes each page of the document to generate digital image data. Furthermore, the image processing unit 80 performs image processing such as color conversion processing, correction processing according to initial settings or user settings, and compression processing on the image data as necessary. The correction according to the user settings is, for example, shading correction. The image processing unit 80 outputs the image data after image processing to the image forming unit 240.

[0055] The stiffness measuring device 410 is disposed in the recording material conveying device 400 (see FIG. 1). The stiffness measuring device 410 transmits the measurement result to the control unit 90.

[0056] [Functional configuration of the control unit] Next, the functional configuration of the control unit 90 will be described with reference to FIG. FIG. 3 is a functional block diagram of the control unit 90.

[0057] As shown in FIG. 3, the control unit 90 includes a paper feed control unit 94, a transport control unit 95, and an image formation control unit 97.

[0058] The paper feed control unit 94 controls the driving of the recording material supply unit 70 of the recording material supply device 100 to supply the recording material S from the recording material supply unit 70 to the conveying unit 50. The recording material supply unit 70 supplies the recording material S to the conveying unit 50 in accordance with the conveying control of the recording material S by the conveying control unit 95.

[0059] The conveyance control unit 95 controls the driving of the recording material supply device 100, the recording material conveying device 400, the image forming apparatus 200, and the conveying units 50, 51, 52, 53, 250, and 350 provided in the post-processing device 300. As a result, the recording material S is conveyed to each location in the image forming system 10. Further, the conveyance control section 95 controls the conveyance mechanism such as the branching section 58 of the recording material conveying device 400 to change the conveyance path of the recording material S.

[0060] When conveying a plurality of recording materials S in accordance with an image forming job, the conveyance control unit 95 guides at least one sheet of recording material S to the second conveyance path 42 of the recording material conveying device 400. The second conveyance path 42 is a path along which the second conveyance unit 52 conveys the recording material S. In the second conveyance path 42, a surface property detection unit 450 detects the surface property of the recording material S. Also, in the second conveyance path 42, a stiffness measurement device 410 measures the stiffness of the recording material S and obtains stiffness information based on the measurement result. Furthermore, in the second conveyance path 42, a resistance value detection unit 460 detects the resistance value of the recording material S.

[0061] Furthermore, the conveyance control unit 95 corrects the control parameters relating to the conveyance of the recording material S in accordance with the stiffness of the recording material S. A specific example of the control parameters relating to the conveyance is the conveyance speed of the recording material S.

[0062] The image formation control unit 97 controls the image forming operation of the image forming unit 240. In addition, the image formation control unit 97 determines control parameters related to image formation according to the stiffness of the recording material S measured by the stiffness measuring device 410. Specific examples of the control parameters related to image formation include the charging potential by the charging unit 242, the transfer current supplied to the primary transfer roller 245 and the secondary transfer roller 247, the fixing temperature and fixing pressure in the fixing unit 248, etc.

[0063] [Structure of stiffness measuring device] Next, the configuration of the stiffness measuring device 410 will be described with reference to FIGS. Fig. 4 is a diagram showing a schematic configuration of stiffness measuring device 410. Fig. 5 is a diagram showing a pair of holding rollers of stiffness measuring device 410 as viewed from above.

[0064] 4, the stiffness measuring device 410 is disposed on the second transport path 42 along which the second transport section 52 transports the recording material S. On the second transport path 42, the transport direction of the recording material S is the vertical direction Z. The stiffness measuring device 410 stops the recording material S in the middle of being transported in the vertical direction Z and measures the stiffness of the recording material S.

[0065] Hereinafter, the conveying direction of the recording material S is referred to as the vertical direction Z. The direction perpendicular to the recording surface of the recording material S conveyed on the second conveying path 42 is referred to as the horizontal direction Y, and the direction perpendicular to the vertical direction Z and the horizontal direction Y is referred to as the recording material width direction X.

[0066] The stiffness measuring device 410 includes a recording material holding section 511 that holds the recording material S, and a stiffness measuring section 512 that measures the stiffness of the recording material S held by the recording material holding section 511 .

[0067] The recording material holding portion 511 is composed of a plurality of clamping members 515. Note that, in Fig. 4, only the clamping member 515 that is closest to the lower end of the recording material S is shown. The clamping member 515 has a pair of holding rollers 521a and 521b, a roller driving portion 522, and a biasing spring 523.

[0068] The rotation axes of the pair of holding rollers 521a, 521b are parallel to the recording material width direction X. As shown in Fig. 5, the length (width) of the pair of holding rollers 521a, 521b in the X direction is longer than the length (width) of the recording material S in the X direction. Therefore, the pair of holding rollers 521a, 521b hold the recording material S over the entire width in the X direction.

[0069] The pair of holding rollers 521a, 521b preferably also serve as conveying rollers. The roller driving unit 522 rotates the holding roller 521a. The roller driving unit 522 has a holding roller motor 524 and a gear train 525 that transmits the rotation of the holding roller motor 524 to the holding roller 521a.

[0070] The biasing spring 523 biases the holding roller 521b toward the holding roller 521a. The direction in which the biasing spring 523 biases the holding roller 521b is the horizontal direction Y. The pair of holding rollers 521a, 521b sandwich the recording material S with a predetermined clamping force, thereby clamping the recording material S. The pair of holding rollers 521a, 521b clamp the recording material S in a position in which the recording surfaces are approximately parallel to the vertical direction Z.

[0071] A recording material detection unit 520 is disposed on the second transport path 42. When the recording material S is disposed at the stiffness measurement position, the recording material detection unit 520 detects the bottom end of the recording material S. The recording material detection unit 520 outputs the detection result, i.e., the fact that the bottom end of the recording material S has been detected, to a control unit 561 (see FIG. 6 ) of the stiffness measuring device 410, which will be described later. As a result, the control unit 561 detects that the recording material S has been disposed at the stiffness measurement position.

[0072] The stiffness measuring unit 512 is disposed below a pair of holding rollers 521a, 521b of the clamping member 515 that is closest to the lower end of the recording material S. The stiffness measuring unit 512 includes a pressing unit 531, a load measuring unit 532, a support mechanism 533, a moving mechanism 534, a home position sensor 535, and a frame 536. The support mechanism 533, the moving mechanism 534, and the home position sensor 535 are disposed within the frame 536.

[0073] The pressing portion 531 presses the lower end of the recording material S. The pressing portion 531 has a blade 531a and a base 531b continuous with one end of the blade 531a in the horizontal direction Y. The blade 531a is formed in a long plate shape that is long in the recording material width direction X so as to be able to contact the entire width of the recording material S transported in the vertical direction Z. The blade 531a contacts a measurement point that is a specific distance above the lower end of the recording material S in the vertical direction Z. In other words, the measurement point is located vertically lower than the portion of the recording material S held by the recording material holding portion 511.

[0074] The load measuring unit 532 is connected to a surface of the base 531b of the pressing unit 531 opposite to a surface continuing to the blade 531a. The load measuring unit 532 measures the load of the reaction force when the pressing unit 531 presses and bends the recording material S. As the load measuring unit 532, for example, a load cell or a pressure sensor can be adopted.

[0075] The support mechanism 533 supports the pressing unit 531 and the load measuring unit 532 so as to be movable in the horizontal direction Y. In other words, the direction in which the pressing unit 531 presses the recording material S is parallel to the direction in which the clamping force of the clamping member 515 closest to the bottom end of the recording material S acts. The support mechanism 533 has a detection unit holding member 541, an abutting member 542, a worm gear 543, and a biasing spring 544. The detection unit holding member 541 and the abutting member 542 are attached to a frame 536.

[0076] The detector holding member 541 is supported by the frame 536 so as to be movable in the horizontal direction Y. Further, a locking portion (not shown) is arranged on the frame 536 to lock the rotation of the detection unit holding member 541 about an axis extending in the horizontal direction Y. The detection unit holding member 541 holds the load measuring unit 532. The detection unit holding member 541 is connected to a surface of the load measuring unit 532 opposite to the surface connected to the pressing unit 531.

[0077] The abutting member 542 faces the detection unit holding member 541 in the horizontal direction Y. The abutting member 542 is fixed to the frame 536. In addition, the abutting member 542 supports one end of a worm gear 543 so as to be rotatable.

[0078] The rotation axis of the worm gear 543 extends in the horizontal direction Y. The movement of the worm gear 543 in the horizontal direction Y is stopped by an abutting member 542. The other end of the worm gear 543 is screwed into the detection unit holding member 541. As a result, when the worm gear 543 rotates, the detection unit holding member 541 moves in the horizontal direction.

[0079] The biasing spring 544 is connected to the detection unit holding member 541 and the abutment member 542. It biases the detection unit holding member 541 toward the abutment member 542. As the biasing spring 544, for example, a tension coil spring or a compression coil spring can be used.

[0080] Backlash occurs between the detection unit holding member 541 and the worm gear 543. Therefore, the detection unit holding member 541 can move slightly in the horizontal direction Y regardless of the rotation of the worm gear 543. In this embodiment, since the biasing spring 544 is provided, the detection unit holding member 541 does not move toward the abutting member 542 due to the influence of the backlash. As a result, when measuring the stiffness of the recording material S, the detection unit holding member 541 and the pressing portion 531 do not shift toward the abutting member 542. As a result, the stiffness of the recording material S can be measured with high accuracy.

[0081] The moving mechanism 534 moves the pressing portion 531 in the horizontal direction Y via the support mechanism 533 . The moving mechanism 534 has a recording material pressing motor 551, and a gear train 552 that transmits the rotation of the recording material pressing motor 551 to the worm gear 543. The recording material pressing motor 551 can be, for example, a stepping motor.

[0082] The home position sensor 535 detects the home positions of the detection unit holding member 541 and the pressing unit 531. The home position of the pressing unit 531 is a position where the pressing unit 531 begins to contact the recording surface of the recording material S. The home position sensor 535 detects the home position of the pressing unit 531 from the position of the detection unit holding member 541.

[0083] The home position of the pressing unit 531 varies depending on the thickness of the recording material S. The thickness of the recording material S and the home position may be associated with each other using table data previously stored in the storage unit 564 (see FIG. 6). The load measuring unit 532 measures the load (pressing force) received from the recording material S when the pressing unit 531 moves a predetermined amount from the home position toward the recording material S in the horizontal direction Y.

[0084] [Functional configuration of stiffness measuring device] Next, the functional configuration of the stiffness measuring device 410 will be described with reference to FIG. FIG. 6 is a block diagram showing an example of the configuration of a control system of the stiffness measuring device 410. As shown in FIG.

[0085] As shown in Fig. 6, the stiffness measuring device 410 has a control unit 561. The control unit 561 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Various functions of the control unit 561 are realized by the CPU executing a predetermined processing program stored in the ROM. The ROM is used as an example of a computer-readable non-transitory recording medium that stores a program executed by the CPU. For this reason, the program is permanently stored in the ROM.

[0086] The control unit 561 controls the holding roller motor 524 of the recording material holding unit 511, the recording material pressing motor 551 of the pressing unit 531, and the load measuring unit 532. The control unit 561 is also electrically connected to the recording material detection unit 520 and the home position sensor 535 by wire or wirelessly. Note that when the pair of holding rollers 521a, 521b (see FIG. 4) also serve as conveying rollers, the holding roller motor 524 may be controlled by the conveying control unit 95 (see FIG. 3).

[0087] The stiffness measuring device 410 measures the stiffness (load) of the recording material S by operating as follows.

[0088] First, the control unit 561 receives the detection result of the recording material detection unit 520 and detects that the recording material S has been placed at the stiffness measurement position. Then, the control unit 561 controls the driving of the holding roller motor 524 to cause the recording material S placed at the stiffness measurement position to be held by the recording material holding unit 511. At this time, the pair of holding rollers 521a, 521b hold the recording material S over its entire width (see FIG. 5). The recording material S held by the recording material holding unit 511 has a posture in which the recording surface is substantially perpendicular to the horizontal direction Y.

[0089] Next, the control unit 561 controls the driving of the recording material pressing motor 551 to move the pressing unit 531 and the load measuring unit 532 in the horizontal direction Y via the detection unit holding member 541. As a result, the pressing unit 531 starts to contact the recording surface of the recording material S. At this time, the home position sensor 535 detects the position of the detection unit holding member 541 and outputs the detection result to the control unit 561. As a result, the control unit 561 detects the home positions of the pressing unit 531 and the detection unit holding member 541. Note that the control unit 561 may determine the moving distances of the pressing unit 531 and the detection unit holding member 541 to the home positions using table data stored in advance in the storage unit 564.

[0090] Next, the control unit 561 controls the driving of the recording material pressing motor 551 to move the pressing unit 531 from the home position to the measurement end position. The distance from the home position to the measurement end position is, for example, 4 mm. The pressing unit 531, which moves from the home position to the measurement end position, presses and bends the recording material S. At this time, the load measuring unit 532 measures the load (pressing force) of the reaction force received from the recording material S and outputs it to the control unit 561. As a result, the control unit 561 obtains the load of the reaction force of the recording material S.

[0091] After acquiring the reaction force load of the recording material S, the control unit 561 releases the pressing state of the recording material S by the pressing unit 531. That is, the control unit 561 controls the driving of the recording material pressing motor 551 to move the pressing unit 531 toward the abutment member 542 (see FIG. 4) side from the home position. This releases the pressing state of the recording material S by the pressing unit 531.

[0092] The control unit 561 calculates stiffness information corresponding to the stiffness of the recording material S based on the load measured when the pressing unit 531 moves from the home position to a predetermined position. In this embodiment, the stiffness information is the amount of change per unit distance of the load measured by the load measuring unit 532. The control unit 561 transmits the calculated stiffness information to the control unit 90 of the image forming system 10.

[0093] As described above, the pressing unit 531 presses the recording material S in the horizontal direction Y, with the recording surface oriented substantially perpendicular to the horizontal direction Y. This makes it possible to minimize the effect of gravity when pressing the recording material S. As a result, the stiffness of the recording material S can be measured with high accuracy.

[0094] [Multiple clamping members] Next, the multiple clamping members 515 will be described with reference to FIG. FIG. 7 is a diagram illustrating a plurality of clamping members 515 of the stiffness measuring device 410. As shown in FIG.

[0095] 7, the multiple clamping members 515 according to this embodiment are composed of clamping members 515A, 515B, and 515C. Of the clamping members 515A, 515B, and 515C, the clamping member 515A is disposed at a position closest to the lower end of the recording material S. The clamping force of the clamping member 515A is parallel to the direction in which the pressing portion 531 presses the recording material S.

[0096] Among the pinching members 515A, 515B, and 515C, the pinching member 515C is disposed at a position farthest from the lower end of the recording material S. The pinching member 515B is disposed between the pinching members 515A and 515C. The pinching force of the pinching members 515B and 515C is in a direction intersecting with the direction in which the pressing portion 531 presses the recording material S.

[0097] 7, when the recording material S is placed at the stiffness measurement position, the distance from the portion of the pair of holding rollers 521a, 521b of the clamping member 515A clamping the recording material S to the lower end of the recording material S is set to a predetermined distance A. It is preferable to set the predetermined distance A in the range of 20 to 40 mm, for example.

[0098] The pair of holding rollers 521a and 521b of the clamping members 515A, 515B, and 515C are formed from a material having the same hardness. For example, rubber, resin, etc. can be used as the material of the pair of holding rollers 521a and 521b. For example, ethylene propylene diene rubber (EDPM) with a hardness of 80° is preferable as the material of the pair of holding rollers 521a and 521b.

[0099] A typical pair of conveying rollers is made of different materials (substances) because it is not considered that the conveyed recording material S is pressed in a direction intersecting the conveying direction. If such a pair of conveying rollers is used as a pair of holding rollers of the stiffness measuring device according to the present invention, the recording material S may shift when the pressing unit 531 presses the recording material S. As a result, the stiffness of the recording material S cannot be measured accurately. On the other hand, the pair of holding rollers 521a, 521b of this embodiment are made of materials having the same hardness. Therefore, even if the pressing unit 531 presses the recording material S, the recording material S can be sandwiched without shifting. As a result, the stiffness of the recording material S can be measured accurately.

[0100] Furthermore, the pair of holding rollers 521a, 521b of the pinching members 515A, 520B, and 520C have the same diameter. This makes it possible to prevent the amount of deformation of the recording material S from differing depending on the direction in which the pressing portion 531 presses the recording material. As a result, the stiffness of the recording material S can be accurately measured.

[0101] [Clamping force of clamping members] Next, the clamping force of clamping member 515A will be described with reference to FIG. 8 and FIGS. 9A and 9B. Fig. 8 is a diagram showing a state in which pressing portion 531 presses recording material S when the clamping force of clamping member 515A is sufficient. Figs. 9A and 9B are diagrams showing a state in which pressing portion 531 presses recording material S when the clamping force of clamping member 515A is insufficient.

[0102] 8, when the clamping force of the clamping member 515A is sufficient, the predetermined distance A does not change even if the pressing unit 531 presses the recording material S. Therefore, the effect of gravity does not change when measuring the reaction force of the recording material S. As a result, the stiffness measuring unit 512 can accurately measure the reaction force of the recording material S.

[0103] In this embodiment, the clamping force of the clamping member 515A is set to an appropriate value, and the pair of holding rollers 521a, 521b of the clamping member 515A are made of materials of the same hardness. This makes it possible to prevent the recording material S from shifting when the pressing unit 531 presses the recording material S. As a result, even if the pressing unit 531 presses the recording material S, the predetermined distance A does not change.

[0104] If the clamping force of the clamping member 515A is insufficient, when the pressing portion 531 presses the recording material S, frictional force is generated between the recording material S and the pressing portion 531, and the recording material S may be pulled downward (see FIG. 9A). In this case, the predetermined distance A changes, and the effect of gravity changes when measuring the reaction force of the recording material S. As a result, the stiffness measuring portion 512 cannot accurately measure the reaction force of the recording material S.

[0105] Furthermore, if the clamping force of the clamping member 515A is insufficient, when the pressing portion 531 presses the recording material S, frictional force is generated between the recording material S and the pressing portion 531, and the recording material S may rise upward (see FIG. 9B). In this case, as in the case shown in FIG. 9A, the predetermined distance A changes, and the effect of gravity changes when measuring the reaction force of the recording material S. As a result, the stiffness measuring portion 512 cannot accurately measure the reaction force of the recording material S.

[0106] [Distance from the clamping part of the clamping member to the bottom edge of the recording material] Next, a case where the distance from the portion where the clamping member 515A clamps the recording material S to the lower end of the recording material S is longer than the predetermined distance A will be described with reference to FIG. FIG. 10 is a diagram showing a state in which the pressing portion 531 presses the recording material S when the distance from the clamping portion of the clamping member 515A to the lower end of the recording material S is equal to or greater than the predetermined distance A. In FIG.

[0107] 10, when the distance from the portion where the clamping members 515A clamp the recording material S to the bottom end of the recording material S is longer than a predetermined distance A, the effect of gravity acting above and below the portion pressed by the pressing unit 531 becomes large. Therefore, the stiffness measuring unit 512 cannot accurately measure the reaction force of the recording material S.

[0108] As described above, in this embodiment, the distance from the portion of the clamping member 515A that clamps the recording material S to the bottom end of the recording material S is set to a predetermined distance A. Therefore, it is possible to minimize the effect of gravity acting above and below the portion pressed by the pressing portion 531. As a result, the stiffness measuring unit 512 can measure the reaction force of the recording material S with high accuracy.

[0109] [Clamping force of multiple clamping members] Next, the clamping force of the clamping members 515A, 515B, 515C will be described with reference to FIG. FIG. 11 is a diagram for explaining the clamping forces of the clamping members 515A, 515B, and 515C in the stiffness measuring device 410. As shown in FIG.

[0110] 11, clamping force F1 of clamping member 515A is greater than clamping force F2 of clamping member 515B and clamping force F3 of clamping member 515C. That is, the spring force of biasing spring 523 of clamping member 515A is greater than the spring forces of biasing springs 523 of clamping members 515B and 515C.

[0111] When the recording material S reaches the stiffness measurement position, the control unit 561 (see FIG. 6) controls the driving of the motors 524 for the holding rollers of the multiple clamping members 515A, 515B, 515C to stop the rotation of the pair of holding rollers 521a, 521b. As a result, the recording material S stops at the stiffness measurement position. At this time, there is variation in the stopping timing of the pair of holding rollers 521a, 521b of the multiple clamping members 515A, 515B, 515C.

[0112] In this embodiment, the clamping force F1 of the clamping member 515A arranged at the position closest to the lower end of the recording material S is set to be larger than the clamping forces F2, F3 of the other clamping members 515B, 515C. This makes it possible to prevent the recording material S from being pulled toward the clamping members 515B, 515C even if there is variation in the stopping timing of the pairs of holding rollers 521a, 521b in the multiple clamping members 515A, 515B, 515C. As a result, the predetermined distance A does not change, and the stiffness measuring unit 512 can measure the reaction force of the recording material S with high accuracy.

[0113] [Parameter setting process] Next, the parameter setting process of the image forming system 10 according to the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart showing the procedure of the parameter setting process of the image forming system 10.

[0114] First, when a print job is started, the transport control unit 95 controls the driving of the transport unit 50 to take out the recording material S specified in the print job from the recording material supply unit 70. Then, the transport control unit 95 controls the driving of the first transport unit 51 and the second transport unit 52 to transport the recording material S along the second transport path 42 of the recording material transport device 400 (S1).

[0115] Next, when the lower end of the recording material S is detected by the recording material detection unit 420 on the second transport path 42, the control unit 561 of the stiffness measuring device 410 controls the driving of the recording material holding unit 511 to stop the transport of the recording material S (S2). As a result, the recording material S stops at the stiffness measurement position. In step S2, the control unit 561 stops the driving of the holding roller motors 524 of the multiple clamping members 515A to 515C to cause the pair of holding rollers 521a, 521b to clamp the recording material S arranged at the stiffness measurement position.

[0116] Next, the control unit 561 operates the stiffness measuring unit 512 of the stiffness measuring device 410 to measure the stiffness of the recording material S (S3). At this time, the control unit 561 controls the driving of the recording material pressing motor 551 to cause the pressing unit 531 to press the recording material S in the horizontal direction Y. Then, the load measuring unit 532 detects the load received from the recording material S that has been pressed and bent by the pressing by the pressing unit 531, and the detection result is captured by the control unit 561. Then, the control unit 561 sends the detection result to the control unit 90 of the image forming system 10 as the stiffness of the recording material S.

[0117] Next, the conveyance control unit 95 controls the driving of the second conveying unit 52 to discharge the recording material S whose stiffness has been measured from the discharge unit 56 (S4). At this time, the control unit 561 drives the holding roller motors 524 in the multiple holding members 515A to 515C to release the holding of the recording material S by the pair of holding rollers 521a, 521b.

[0118] Next, the control unit 90 sets control parameters based on the stiffness of the recording material S (S5). The correspondence between the stiffness of the recording material S and the control parameters may be made using table data previously stored in the storage unit 98. That is, the control unit 90 reads out from the storage unit 98 the control parameters corresponding to the stiffness of the recording material S measured by the stiffness measuring device 410.

[0119] The control parameters to be set include at least one of a recording material conveying parameter, a recording material curl correction parameter, an image forming parameter, and a post-processing parameter.

[0120] A specific example of the recording material conveying parameters is the conveying speed.Specific examples of the recording material curl correction parameters are the pressure applied to the recording material by the curl correction roller, and the contact time between the curl correction roller and the recording material.Specific examples of the image forming parameters are the charging potential by the charging unit 242, the transfer current supplied to the primary transfer roller 245 and the secondary transfer roller 247, and the fixing temperature and fixing pressure in the fixing unit 248.Specific examples of the post-processing parameters are the driving pressure for stapling and the drive torque for folding.

[0121] The conveying parameters and curl correction parameters are parameters set by the conveying control unit 95. The image formation parameters are parameters set by the image formation control unit 97. The post-processing parameters are parameters set by a post-processing control unit (not shown) included in the control unit 90. Note that the control parameters set in step S5 may be control parameters other than the control parameters listed here.

[0122] [Variations] Next, a modified example of the clamping member will be described with reference to FIG. FIG. 13 is a diagram showing a modified example of a clamping member in a stiffness measuring device.

[0123] 13, a clamping member 515D according to the modification includes a pair of holding rollers 521a, 521b, a roller driving unit 522 (see FIG. 4), and a biasing spring 526. The pair of holding rollers 521a, 521b and the roller driving unit 522 are the same as those of the clamping member 515A of the first embodiment. The roller driving unit 522 rotates the holding roller 521b.

[0124] The biasing spring 526 biases the holding roller 521a toward the holding roller 521b. The direction in which the biasing spring 526 biases the holding roller 521a is the same as the direction in which the pressing portion 531 presses the recording material S. The pair of holding rollers 521a, 521b sandwich the recording material S with a predetermined clamping force, thereby clamping the recording material S. The pair of holding rollers 521a, 521b clamp the recording material S with the recording surfaces approximately parallel to the vertical direction Z.

[0125] In this way, the direction in which the holding roller 521a is biased to generate the clamping force of the clamping member 515D may be the same as the direction in which the pressing portion 531 presses the recording material S. Even in this case, the pair of holding rollers 521a, 521b are formed from materials of the same hardness. Therefore, even if the pressing portion 531 presses the recording material S, the recording material S can be clamped without shifting. As a result, the stiffness of the recording material S can be accurately measured.

[0126] The embodiment of the stiffness measuring device and the image forming system of the present invention have been described above, including their effects. However, the stiffness measuring device and the image forming system of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible within the scope of the invention described in the claims.

[0127] The above-mentioned embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0128] For example, the image forming system 10 of the above-described embodiment is configured to include the stiffness measuring device 410 in the recording material transport device 400. However, the stiffness measuring device according to the present invention may be provided at any position upstream of the image forming unit in the recording material transport direction. The stiffness measuring device according to the present invention may be provided in, for example, the image forming apparatus 200 or the recording material supply device 100. [Explanation of symbols]

[0129] 10...image forming system, 41...first transport path, 42...second transport path, 43...third transport path, 50...transport section, 51...first transport section, 52...second transport section, 53...third transport section, 54...transport roller, 55...entrance, 56...discharge section, 57...exit, 58...branch section, 70...recording material supply section, 80...image processing section, 90...control section, 91...CPU, 92...ROM, 93...RAM, 94...paper feed control section, 95...transport control section, 97...image formation control section, 98...storage section, 99...communication section, 100...recording material supply device, 200...image forming device, 220...operation display section, 230...scanner, 240...image forming section, 300...post-processing device, 400...recording material transport device, 410: stiffness measuring device, 511: recording material holding section, 512: stiffness measuring section, 520: recording material detection section, 521a, 521b: holding rollers, 522: roller drive section, 523, 526: biasing spring, 524: motor for holding roller, 525: gear train, 531: pressing section, 532: load measuring section, 533: support mechanism, 534: moving mechanism, 536: frame, 541: detection section holding member, 542: abutment member, 543: worm gear, 544: biasing member, 551: motor for pressing recording material, 552: gear train, 561: control section

Claims

1. a clamping member for clamping the recording material so that the recording surface of the recording material is substantially parallel to the vertical direction; a pressing portion that presses a recording surface of the recording material held by the holding member; a stiffness acquisition unit that measures a reaction force of the recording material when pressed by the pressing unit and acquires the measured reaction force as stiffness of the recording material, The portions of the clamping members that clamp the recording material are made of materials having the same hardness. Stiffness measuring device.

2. The direction in which the clamping force of the clamping members acts is perpendicular to the vertical direction.

2. The stiffness measuring device according to claim 1.

3. The direction in which the clamping force of the clamping members acts is parallel to the direction in which the pressing portion presses the recording material.

2. The stiffness measuring device according to claim 1.

4. The clamping member clamps the recording material and stops it at a predetermined position.

2. The stiffness measuring device according to claim 1.

5. At the predetermined position, a distance from a portion of the clamping member that clamps the recording material to a lower end of the recording material is a predetermined distance, The clamping member generates a clamping force that ensures the predetermined distance when the pressing portion presses the recording material.

5. The stiffness measuring device according to claim 4.

6. The clamping member is one or more pairs of rollers.

2. The stiffness measuring device according to claim 1.

7. The roller pair closest to the pressing portion in the one or more roller pairs has the same diameter.

7. The stiffness measuring device according to claim 6.

8. The roller pair closest to the pressing portion among the one or more roller pairs has a larger clamping force than the other roller pairs.

7. The stiffness measuring device according to claim 6.

9. The width of the roller pair that is closest to the pressing portion among the one or more roller pairs is greater than the width of the recording material.

7. The stiffness measuring device according to claim 6.

10. an image forming section for forming an image on a recording material; a recording material storage section capable of storing the recording material; a recording material conveying section provided between the recording material container and the image forming section; a stiffness measuring device that is disposed in the recording material conveying section and measures stiffness of the recording material; a control unit that sets image formation parameters in accordance with the measurement results of the stiffness measuring device, The stiffness measuring device is a clamping member that clamps the recording material so that a recording surface of the recording material is substantially parallel to a vertical direction; a pressing portion that presses a recording surface of the recording material held by the holding member; a stiffness acquisition unit that measures a reaction force of the recording material when pressed by the pressing unit and acquires the measured reaction force as stiffness of the recording material, The portions of the clamping members that clamp the recording material are made of materials having the same hardness. Image forming system.

Images