Stiffness measuring device and image forming system

Abstract

The reaction force is measured suitably with a simple configuration. [Solution] The stiffness measuring device 50 comprises a blade 52 that presses against the paper S, a load cell 53 attached to the blade 52 that measures the reaction force received by the blade 52 when the blade 52 presses against the paper S, and a control unit 60 that acquires the stiffness of the paper S based on the reaction force measured by the load cell 53. The blade 52 has a notch 52b at a position corresponding to the load cell 53.

Description

Technical Field

[0001] The present invention relates to a stiffness measuring device for measuring the stiffness of a sheet, and an image forming system including the same.

Background Art

[0002] In an image forming system that forms an image on a sheet (sheet material), a technique for detecting the stiffness of the sheet and setting various control parameters is known. For example, in the technique described in Patent Document 1, the stiffness of the sheet is measured by holding the sheet in a stopped state and pressing the end of the sheet to measure the reaction force.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The blade that presses the sheet during stiffness measurement is integrally configured with a load cell that measures the reaction force. The load cell needs to be attached to the blade so that the strain gauge portion that detects strain does not contact the blade. However, when a spacer is simply interposed between the blade and the load cell for the purpose of separating the strain gauge portion and the blade (see FIG. 9), it causes an increase in the number of parts and complication of assembly. In addition, there is a concern about deterioration of the holding accuracy of the blade due to the interposition of the spacer, and thus deterioration of the pressing accuracy. Furthermore, since the pressing unit increases in size by the amount of the spacer, it is necessary to secure a wider operating range for it. As a result, the arrangement of the surrounding components is restricted, and the degree of freedom in component layout is reduced.

[0005] This invention has been made in view of the above circumstances, and aims to measure reaction force suitably with a simple configuration. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a stiffness measuring device, A pressing part that presses the sheet material, A reaction force measuring unit attached to the pressing portion is used to measure the reaction force received by the pressing portion when the pressing portion presses the sheet material, Based on the reaction force measured by the reaction force measuring unit, an acquisition unit obtains the stiffness of the sheet material, Equipped with, The pressing portion has a notch at a position corresponding to the reaction force measuring portion. [Effects of the Invention]

[0007] According to the present invention, reaction force can be suitably measured with a simple configuration. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an image forming system according to an embodiment. [Figure 2] This is a side view of a stiffness measuring device according to an embodiment. [Figure 3] This is a plan view of a stiffness measuring device according to an embodiment. [Figure 4] This is a block diagram showing a schematic control configuration of a stiffness measuring device according to an embodiment. [Figure 5] This is a flowchart showing the operation flow of the stiffness measuring device according to the embodiment. [Figure 6] This is a schematic diagram illustrating the operation of the stiffness measuring device according to the embodiment. [Figure 7] This is a schematic diagram illustrating the operation of the stiffness measuring device according to the embodiment. [Figure 8] This is a partial plan view of a stiffness measuring device according to an embodiment. [Figure 9]This diagram illustrates a configuration in which a spacer is placed between the blade and the load cell. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings.

[0010] [Configuration of the image forming system] Figure 1 shows the image forming system 1 according to this embodiment. As shown in this figure, the image forming system 1 comprises a paper feeder 10, a paper transporter 20, an image forming apparatus 30, and a post-processing device 40.

[0011] The paper feeder 10 is equipped with multiple paper trays 12, each holding various types of paper S classified by basis weight, size, etc. Based on a print job from a control unit (not shown), the paper feeder 10 supplies predetermined paper S one sheet at a time to the paper transporter 20. Paper S is a recording medium on which an image is formed, and is an example of a sheet material according to the present invention. The material of paper S is not particularly limited, as long as it is a sheet material on which the stiffness can be measured.

[0012] The paper transport device 20 is located downstream of the paper feed device 10 in the transport direction and upstream of the image forming apparatus 30 in the transport direction. The paper transport device 20 has a first transport path 21 that transports the paper S transported from the paper feed device 10 to the image forming apparatus 30, and a second transport path 22 that branches off from the first transport path 21. The second transport path 22 transports the paper S to the second discharge port 23, for example, when acquiring and registering information about the paper S. The second transport path 22 is equipped with a stiffness measuring device 50 for acquiring the stiffness of the paper S. As will be described later, the stiffness measuring device 50 measures the stiffness of the paper S when its transport is temporarily stopped in the middle of the second transport path 22. The stiffness of the paper S is an indicator of its resistance to bending and can be expressed in various physical quantities. The detailed configuration of the stiffness measuring device 50 will be described later.

[0013] The image forming apparatus 30 forms an image (transfers and prints) on the sheet S conveyed from the paper feeding apparatus 10 by using an electrophotographic process, and reads an image from an original and forms it on the sheet S. Further, the image forming apparatus 30 receives job data including image data and setting information in PDL (Page Description Language) format from an external client terminal through a network, and forms an image on the sheet S based on this job data. The client terminal is, for example, a PC, a tablet terminal, a smartphone, or the like. The image forming apparatus 30 discharges the sheet S on which an image has been formed to the post-processing apparatus 40.

[0014] The post-processing apparatus 40 executes predetermined post-processing on the sheet S on which an image has been formed by the image forming apparatus 30 based on a post-processing job from a control unit (not shown). Examples of the post-processing include perforation, folding, foil stamping, binding, cutting, stapling, gluing, sewing, and the like. The post-processing apparatus 40 discharges the sheet S on which the post-processing has been completed to the first discharge port 42.

[0015] [Configuration of Stiffness Measuring Device] FIG. 2 and FIG. 3 are a side view and a plan view of the stiffness measuring device 50. As shown in FIGS. 2 and 3, the stiffness measuring device 50 is disposed in the second conveyance path 22 of the paper conveyance device 20. In the second conveyance path 22, the sheet S is conveyed from the lower side to the upper side by a plurality of conveyance rollers 25 (see FIG. 1). The stiffness measuring device 50 measures the stiffness of the sheet S at a portion of the second conveyance path 22 where the conveyance direction D1 of the sheet S is vertically upward. Hereinafter, the vertical direction along the conveyance direction D1 is referred to as the Z direction. Further, the direction orthogonal to the recording surface (main surface) of the sheet S conveyed in the conveyance direction D1 is referred to as the Y direction, and the width direction of the sheet S orthogonal to both the Z direction and the Y direction is referred to as the X direction.

[0016] Specifically, the stiffness measuring device 50 includes a pair of holding rollers 51 and a pressing unit 55. The pair of holding rollers 51 are holding parts capable of stopping and holding the paper S being transported along the transport direction D1. Specifically, the pair of holding rollers 51 are arranged side by side in the Y direction and are biased, for example, in a direction toward each other, thereby gripping and holding the paper S with a predetermined holding force. The pair of holding rollers 51 hold the paper S with its main surface oriented approximately perpendicular to the Y direction. Furthermore, although not particularly limited, it is preferable that the pair of holding rollers 51 also serve as drivable transport rollers.

[0017] The pressing unit 55 is positioned below the holding roller 51 and presses the edge of the paper S held by the holding roller 51 to measure the reaction force. Specifically, the pressing unit 55 comprises a blade 52, a load cell 53, and a moving mechanism 54.

[0018] The blade 52 is an example of a pressing part according to the present invention, and presses the paper S during stiffness measurement. The blade 52 is formed in a long rod shape along the X direction. The end face of the blade 52 on one side (left side in Figures 2 and 3) that is closer to the transport path R of the paper S in the Y direction is a pressing surface 52a that presses the paper S. The length L1 of the pressing surface 52a in the X direction is longer than the maximum width of the paper S. The blade 52 presses the paper S with its pressing surface 52a along a pressing direction D2 that is perpendicular to the transport direction D1 and goes from the other side to the one side in the Y direction.

[0019] Furthermore, the blade 52 has a concave notch 52b on the other side in the Y direction, which is located opposite the pressing surface 52a in the Y direction. The notch 52b is formed at a position in the X direction corresponding to the load cell 53. Specifically, the notch 52b is located near the mounting portion between the blade 52 and the load cell 53. More specifically, the notch 52b is formed in the X direction at a position corresponding to the portion of the load cell 53 excluding the first mounting portion 531 described later. In other words, the notch 52b is not formed in the portion of the load cell 53 corresponding to the first mounting portion 531 described later, but is formed in the portion corresponding to the second mounting portion 532 and the strain gauge portion 533 described later. This notch 52b prevents contact between the blade 52 and the load cell 53 (strain gauge portion 533). Furthermore, the notch 52b only needs to be formed in a position corresponding to the strain gauge portion 533 of the load cell 53. More specifically, the notch 52b only needs to be formed in a position corresponding to the load cell 53.

[0020] The load cell 53 is an example of a reaction force measuring unit according to the present invention, and measures the reaction force received by the blade 52 when the blade 52 presses against the paper S. The load cell 53 is a beam type formed in a rectangular prism shape that is elongated in the X direction, and is positioned on the other side in the Y direction from the blade 52. That is, the load cell 53 is positioned on the opposite side in the Y direction from the paper S that is pressed by the blade 52, via the blade 52. The load cell 53 is positioned in the center of the blade 52 in the X direction. More specifically, the center position C in the X direction of the blade 52 and the load cell 53 are approximately the same. Also, the center of the paper S that is transported and held by the holding roller 51 is approximately the same as the center position C in the width direction.

[0021] The load cell 53 has a first mounting portion 531 and a second mounting portion 532 arranged side by side in the X direction. The first mounting portion 531 is provided on one end of the load cell 53 in the X direction (the lower side in Figure 3) and is attached to the blade 52. More specifically, the load cell 53 is fixed to the blade 52, for example by screws or adhesive, with one surface of the first mounting portion 531 in the Y direction in contact with the other surface of the blade 52 in the Y direction. The first mounting portion 531 is positioned in the X direction of the blade 52 where there is no notch 52b, and the blade 52 and the load cell 53 are in contact only at the first mounting portion 531. The second mounting portion 532 is provided on the other end of the load cell 53 in the X direction (upper side in Figure 3) and is attached to the moving mechanism 54. More specifically, the load cell 53 is fixed to the moving mechanism 54, for example, by screws or adhesive, with the other surface of the second mounting portion 532 in the Y direction in contact with one surface of the moving mechanism 54 in the Y direction. The second mounting portion 532 is positioned in the X direction on the blade 52, corresponding to the notch 52b. The central portion of the load cell 53 in the X direction, located between the first mounting portion 531 and the second mounting portion 532, is a strain gauge portion 533. The strain gauge portion 533 is not in contact with either the blade 52 or the moving mechanism 54. The strain gauge portion 533 in this embodiment is not particularly limited, but one side of the strain gauge portion 533 in the Y direction protrudes slightly more than the first mounting portion 531 and the second mounting portion 532. The strain gauge portion 533 has a strain gauge (not shown) attached to its side surface in the Y direction. The strain gauge detects the strain generated in the strain gauge portion 533 and outputs it to the control unit 60 (see Figure 4). Furthermore, a concave second notch 533a is formed on the other side of the strain gauge portion 533 in the Y direction. The second notch 533a is formed in the portion corresponding to the moving mechanism 54, and a part of one end in the X direction extends to the first mounting portion 531. This second notch 533a reduces the risk of contact between the strain gauge portion 533 and the moving mechanism 54.

[0022] The moving mechanism 54 moves the blade 52 in the Y direction perpendicular to the paper S. The moving mechanism 54 is formed in the shape of a rectangular box and is attached to the second mounting portion 532 of the load cell 53. In this embodiment, the moving mechanism 54 is supported so as to be movable on a guide rail 541 along the Y direction. The other side of the guide rail 541 in the Y direction is fixed to a case plate 542. A rack gear 543 extending in the Y direction is provided on the lower surface of the moving mechanism 54. The rack gear 543 meshes with a drive motor 544 (see Figure 4), such as a stepping motor. With this configuration, the moving mechanism 54 moves in the Y direction together with the blade 52 fixed via the load cell 53 as the drive motor 544 drives. The configuration of the moving mechanism 54 is not particularly limited, as long as it can move the blade 52 in the Y direction.

[0023] Figure 4 is a block diagram showing the schematic control configuration of the stiffness measuring device 50. As shown in this figure, the stiffness measuring device 50 includes a detection sensor 62 and a control unit 60. The detection sensor 62 is positioned, for example, next to the transport path R of the paper S upstream of the holding roller 51 in the transport direction D1, and detects the position of the paper S in the transport direction D1. The detection sensor 62 in this embodiment is a sensor that can detect the passage of the paper S in the transport direction D1, i.e., the lower end of the paper S, and outputs the detection result to the control unit 60. The control unit 60 is composed of components such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory), and controls the operation of each part of the stiffness measuring device 50. Specifically, the control unit 60 controls the operation of the drive motor 544 of the holding roller 51 and the moving mechanism 54 based on the output from the detection sensor 62, and acquires the stiffness of the paper S based on the output from the strain gauge of the load cell 53. Note that the control unit 60 does not have to control only the stiffness measuring device 50; for example, it may control the entire image forming system 1.

[0024] [Operation of the stiffness measuring device] The operation of the stiffness measuring device 50 during stiffness measurement will be explained. Figure 5 is a flowchart showing the operation flow of the stiffness measuring device 50 during stiffness measurement. Figures 6 and 7 are schematic diagrams illustrating the operation of the stiffness measuring device 50. Figure 8 is a partial plan view of the stiffness measuring device 50, and Figure 9 is a diagram illustrating a configuration in which a spacer is placed between the blade 52 and the load cell 53. Here, for example, the stiffness measurement of the paper S being transported is performed based on an execution command from the control unit 60. The control unit 60 executes each process of the stiffness measurement based on a program stored in advance.

[0025] As shown in Figure 5, during stiffness measurement, the control unit 60 first stops the transporting paper S at a predetermined position using the holding roller 51 based on the output of the detection sensor 62 and holds it (step S1; Figure 6). Specifically, the control unit 60 stops transporting the paper S and holds the paper S with the holding roller 51 after a predetermined time has elapsed since the detection sensor 62 detected the passage of the rear end of the paper S. As a result, the paper S is held at a predetermined stiffness measurement position where the rear end (lower end) in the transport direction D1 is located at a predetermined vertical distance from, for example, the nip portion of the holding roller 51.

[0026] Next, the control unit 60 drives the drive motor 544 of the moving mechanism 54 to move the blade 52 in the pressing direction D2, pressing the rear end of the paper S (step S2; Figure 7). As a result, the rear end of the paper S is pushed and bent to one side in the Y direction, with the nip portion of the holding roller 51 as the base end. Specifically, the control unit 60 detects, for example, the position where the tip of the blade 52 begins to contact the main surface of the paper S, based on the output of the load cell 53, and sets this position as the reference position of the blade 52. The control unit 60 moves the blade 52 to one side in the Y direction by a predetermined distance L4 (for example, several mm) from the reference position. As a result, the blade 52 pushes and bends the rear end of the paper S.

[0027] Next, the control unit 60 measures the reaction force that the blade 52 receives from the paper S and obtains the stiffness of the paper S based on the measured reaction force (step S3). Specifically, the control unit 60 obtains the reaction force that the blade 52 receives from the paper S from the load cell 53, and for example, obtains this reaction force (pressing force) as the stiffness of the paper S.

[0028] In this embodiment, the stiffness measuring device 50 has a notch 52b in the blade 52 at a position corresponding to the load cell 53, as shown in Figure 8. This effectively avoids contact between the blade 52 and the load cell 53. In contrast, if a spacer 71 is placed between the blade 52 and the load cell 53 to avoid contact between the blade 52 and the strain gauge section 533, as shown in Figure 9, the pressing unit 55 becomes larger on the other side in the Y direction. In this case, the number of parts increases and assembly becomes more complicated due to the spacer 71. Furthermore, there are concerns that the holding accuracy of the blade 52 will deteriorate due to the interposition of the spacer 71, and consequently, the pressing accuracy will deteriorate. Moreover, because the pressing unit 55 is larger due to the spacer 71, it becomes necessary to secure a wider range of motion. As a result, the arrangement of surrounding components is restricted, and the degree of freedom in component layout decreases. The stiffness measuring device 50 of this embodiment allows for the measurement of reaction forces in a simple configuration without incurring such disadvantages.

[0029] Next, the control unit 60 releases the pressure on the paper S by the blade 52, as shown in Figure 5 (step S4). Here, the control unit 60 drives the drive motor 544 of the moving mechanism 54 to move the blade 52 in the Y direction, returning it to its normal position (position in Figure 2) on the other side of the transport path R in the Y direction. This releases the pressure on the paper S by the blade 52.

[0030] Next, the control unit 60 releases the paper S from the holding roller 51 and transports the paper S with the transport roller 25 to discharge it from the second discharge port 23 (step S5). This completes the measurement of the stiffness of the paper S. The acquired stiffness of the paper S is used to set control parameters related to image formation. These control parameters may be set in the same manner as, for example, determining the image formation conditions described in Japanese Patent Application Publication No. 2023-030480.

[0031] [Technical effects of this embodiment] As described above, according to this embodiment, the blade 52 (pressing portion) has a notch 52b at a position corresponding to the load cell 53 (reaction force measuring portion). This prevents contact between the blade 52 and the load cell 53. In other words, unlike the case where a spacer is interposed between the blade 52 and the load cell 53, contact between the blade 52 and the load cell 53 can be suitably avoided without increasing the number of parts or complicating assembly. Furthermore, it does not lead to a deterioration in pressing accuracy due to a deterioration in the holding accuracy of the blade 52, nor does it result in a decrease in the degree of freedom of component layout due to an increase in the size of the pressing unit 55. Therefore, the reaction force can be measured suitably with a simple configuration.

[0032] Furthermore, according to this embodiment, the notch 52b of the blade 52 is formed in a position corresponding to at least the strain gauge portion 533 of the load cell 53. This makes it possible to more reliably avoid contact between the blade 52 and the strain gauge section 533.

[0033] Furthermore, according to this embodiment, the blade 52 contacts the load cell 53 only at the first mounting portion 531. This prevents contact between the blade 52 and the strain gauge portion 533, and allows the reaction force received by the blade 52 to be suitably transmitted to the load cell 53.

[0034] Furthermore, according to this embodiment, the second mounting portion 532 of the load cell 53, which is attached to the moving mechanism 54 (another component), is positioned on the blade 52 at a location corresponding to the notch 52b. This also prevents contact between the blade 52 and the second mounting portion 532.

[0035] Furthermore, according to this embodiment, the blade 52 is formed to be elongated along the width direction (X direction) of the paper S, and the load cell 53 is positioned in the center of the blade 52 in the longitudinal direction. This allows the load cell 53 to suitably measure the reaction force that the blade 52 receives over a wide area in the X direction.

[0036] Furthermore, according to this embodiment, the transport direction D1 of the paper S is vertical, and the blade 52 presses the sheet material in a direction perpendicular to the transport direction D1. This minimizes the effect of gravity when pressing down on the paper S, and consequently, allows for more accurate stiffness measurements.

[0037] Furthermore, according to this embodiment, the pressing surface 52a of the blade 52 that presses against the paper S is longer than the maximum width of the paper S. This allows for optimal pressure to be applied to the paper S across its entire width, and consequently, the stiffness of the paper S can be measured effectively.

[0038] Furthermore, according to this embodiment, the load cell 53 is positioned on the opposite side of the paper S that is pressed by the blade 52, via the blade 52. This allows the reaction force acting from the paper S to the blade 52 to be suitably measured by the load cell 53.

[0039] Furthermore, according to this embodiment, the blade 52 presses against the edge of the paper S. This allows for the curving of only the edges of the paper S, thereby generating a suitable reaction force. Consequently, the stiffness can be measured effectively.

[0040] Furthermore, according to this embodiment, the holding roller 51 stops and holds the paper S during transport, and the blade 52 presses the paper S held by the holding roller 51. This allows the paper S to be held while being transported and its stiffness to be measured appropriately.

[0041] [others] Although one embodiment of the present invention has been described above, the embodiments to which the present invention can be applied are not limited to the embodiments and their modifications described above, and can be modified as appropriate without departing from the spirit of the present invention.

[0042] For example, in the above embodiment, the transport direction D1 of the paper S is assumed to be aligned with the vertical direction, but the transport direction according to the present invention does not have to be aligned with the vertical direction. Furthermore, in the above embodiment, the case in which the stiffness measuring device 50 is provided on the paper transport device 20 was described. However, the position of the stiffness measuring device in the image forming system is not particularly limited, and it may be placed, for example, on the image forming device. [Explanation of symbols]

[0043] 1. Image forming system 10 Paper feeder 20 Paper transport device 25 Conveyor rollers 50 Stiffness measuring device 51 Retaining roller (retaining part) 52 Blade (pressing part) 52a Pressing surface 53 Load cell (reaction force measuring section) 531 First mounting section 532 Second mounting section 533 Strain gauge section 54 Moving mechanism 55 Pressing Unit 60 Control Unit (Acquisition Unit) C center position D1 Conveying direction D2 Pressing direction R transport route S Paper (sheet material)

Claims

1. A pressing part that presses the sheet material, A reaction force measuring unit attached to the pressing portion is used to measure the reaction force received by the pressing portion when the pressing portion presses the sheet material, Based on the reaction force measured by the reaction force measuring unit, an acquisition unit obtains the stiffness of the sheet material, Equipped with, The pressing portion has a notch at a position corresponding to the reaction force measuring portion. Stiffness measuring device.

2. The reaction force measuring unit has a strain gauge unit for detecting strain, The notch is formed at least at a position corresponding to the strain gauge portion. The stiffness measuring device according to claim 1.

3. The reaction force measuring unit has a first mounting portion that is attached to the pressing portion, The pressing portion contacts the reaction force measuring portion only at the first mounting portion. The stiffness measuring device according to claim 1.

4. The reaction force measuring unit has a first mounting portion attached to the pressing portion and a second mounting portion attached to another member. The first mounting portion and the second mounting portion are arranged side by side along the longitudinal direction of the pressing portion, The first mounting portion is attached to the portion of the pressing portion that does not have a notch. The second mounting portion is positioned in the pressing portion at a location corresponding to the notch. The stiffness measuring device according to claim 1.

5. The pressing portion is formed to be elongated along the width direction of the sheet material that the pressing portion presses, The reaction force measuring section is located in the center of the pressing section in the longitudinal direction. The stiffness measuring device according to claim 1.

6. The conveying direction of the sheet material is vertical. The pressing portion presses the sheet material in a direction perpendicular to the conveying direction. The stiffness measuring device according to claim 1.

7. The pressing portion has a portion that presses the sheet material longer than the maximum width of the sheet material. The stiffness measuring device according to claim 1.

8. The reaction force measuring unit is positioned on the opposite side of the sheet material that is pressed by the pressing unit, via the pressing unit. The stiffness measuring device according to claim 1.

9. The system includes a moving mechanism for moving the pressing portion, The moving mechanism moves the pressing portion perpendicular to the sheet material. The stiffness measuring device according to claim 1.

10. The reaction force measuring unit has a second mounting portion that is attached to the moving mechanism. The stiffness measuring device according to claim 9.

11. The pressing portion presses the edge of the sheet material. The stiffness measuring device according to claim 1.

12. It is equipped with a holding part that can stop and hold the sheet material while it is being transported, The pressing portion presses the sheet material held by the holding portion. The stiffness measuring device according to claim 1.

13. Image forming apparatus and A paper feeding device that supplies the sheet material to the image forming apparatus, A stiffness measuring device according to any one of claims 1 to 12, Equipped with, The stiffness measuring device is positioned in the sheet material transport path provided between the paper feeding device and the image forming apparatus. Image forming system.

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