Sheet state detection device and image formation system

Abstract

To provide a sheet state detection device capable of accurately detecting a sheet state by reducing detection variation in the sheet state, and an image forming system.SOLUTION: The sheet state detection device comprises: a first conveyance unit 22 that conveys a sheet; a second conveyance unit 23 that is disposed on the downstream side in a sheet conveying direction of the first conveyance unit 22, and conveys the sheet; and a detection unit 24 that is disposed between the first conveyance unit 22 and the second conveyance unit 23, and detects a sheet state of the sheet. At least one of a first contact width which is a contact width when the first conveyance unit 22 comes into contact with a sheet surface of the sheet and a second contact width which is a contact width when the second conveyance unit 23 comes into contact with the sheet surface of the sheet is greater than a width of a detection range of the detection unit 24. The detection unit 24 is disposed so as to set the detection range within the contact width equal or greater in length to the width of the detection range in a width direction of the sheet.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a paper condition detection device and an image forming system. [Background technology]

[0002] Conventionally, there is known a technique for detecting the state of paper during transport in a paper transport device, an image forming device, etc. The detected paper state is, for example, the paper position including the leading edge position, the trailing edge position, and the side edge positions of the paper. Also, the detected paper properties include thickness, moisture content, stiffness, surface properties, and electrical resistance. Among these detected paper states, there are some whose detection accuracy is greatly affected by the paper posture. The paper posture includes sagging, wrinkles, undulations, etc. of the paper.

[0003] Therefore, in order to prevent problems with the paper transport, a means is provided for maintaining the paper in a desired orientation during transport. For example, a configuration has been disclosed in which a distance measuring sensor is provided between an upstream roller and a downstream roller to measure the distance to the paper surface (see, for example, Patent Document 1). According to the configuration described in Patent Document 1, the amount of slack in the paper can be appropriately maintained by controlling the rotation speeds of the upstream and downstream rollers based on the amount of slack in the paper. Also disclosed is a configuration that provides a detection member that detects the load current value of a drive member that drives a downstream roller (see, for example, Patent Document 2). In the configuration described in Patent Document 2, first, the amount of slack in the paper is grasped based on the load current value of the drive member, and speed control 1 of the upstream roller is performed. Then, when the load current value reaches a predetermined value, speed control 2 of the upstream roller is performed to prevent the slack in the paper from becoming too large. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-127227 [Patent Document 2] JP 2021-181357 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in both of the configurations described in Patent Documents 1 and 2, the rotation speed of the roller is corrected according to the amount of sagging after the sagging occurs, so the amount of sagging fluctuates during transport and affects the accuracy of detecting the paper state.In addition, since there is no configuration to suppress sagging in the width direction of the paper, it is difficult to maintain a stable paper posture.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a paper condition detection device and an image forming system that are capable of detecting the paper condition with high accuracy by reducing the variation in detection of the paper condition. [Means for solving the problem]

[0007] The invention described in claim 1 has been made to achieve the above object, In the paper condition detection device, a first conveying unit that conveys paper; a second transport section that is disposed downstream of the first transport section in a transport direction of the paper and transports the paper; a detection unit disposed between the first transport unit and the second transport unit and configured to detect a state of the paper; Equipped with at least one of a first contact width, which is a contact width when the first transport unit contacts the paper surface, and a second contact width, which is a contact width when the second transport unit contacts the paper surface, is equal to or greater than the width of the detection range of the detection unit; The detection unit is characterized in that it is disposed in a width direction of the paper such that the detection range falls within the contact width, which is equal to or greater than the width of the detection range.

[0008] The invention described in claim 2 is the paper state detection device described in claim 1, the first transport section includes a first roller pair that is a pair of first rollers that sandwich and transport the paper; The first contact width is the contact width of at least one of the pair of first rollers.

[0009] The invention as set forth in claim 3 is the paper state detection device as set forth in claim 1, the second transport section includes a second roller pair that is a pair of second rollers that sandwich and transport the paper, The second contact width is the contact width of at least one of the pair of second rollers.

[0010] The invention as set forth in claim 4 is the paper state detection device as set forth in claim 2, The first contact width is a contact width of all the first rollers forming the first roller pair.

[0011] The invention as set forth in claim 5 is the paper state detection device as set forth in claim 3, The second contact width is a contact width of all the second rollers forming the second roller pair.

[0012] The invention as set forth in claim 6 is the paper state detection device as set forth in claim 1, The second transport section is characterized in that the transport speed of the paper is faster than that of the first transport section.

[0013] The invention as set forth in claim 7 is the paper state detection device as set forth in claim 1, The detection unit detects a physical property of the paper.

[0014] The invention as set forth in claim 8 is the paper state detection device as set forth in claim 1, The detection unit detects a state of the paper being conveyed.

[0015] The invention described in claim 9 is In an image forming system, A paper state detection device according to any one of claims 1 to 8, an image forming apparatus for forming an image on the paper whose state has been detected by the paper state detection device; The present invention is characterized by comprising: Effect of the Invention

[0016] According to the present invention, it is possible to reduce the variation in detection of the paper condition and to detect the paper condition with high accuracy. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing a schematic configuration of an image forming system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a functional block diagram showing a control structure of the image forming system according to the embodiment. [Diagram 3] FIG. 2 is a plan view showing an example of a configuration of a paper state detection device. [Figure 4] 4 is a diagram showing an example of a state in which a slack occurs in a sheet being conveyed in the configuration shown in FIG. 3. FIG. [Diagram 5] 11A and 11B are a plan view and a side view showing another example of the configuration of a paper state detection device. [Figure 6] 11A and 11B are a plan view and a side view showing another example of the configuration of a paper state detection device. [Figure 7] 11A and 11B are a plan view and a side view showing another example of the configuration of a paper state detection device. [Figure 8] 11A and 11B are a plan view and a side view showing another example of the configuration of a paper state detection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0019] 1 and 2, an image forming system 1 according to this embodiment includes a paper feeder 10, a paper state detection device 20, and an image forming device 30. In the image forming system 1, the paper feeder 10, the paper state detection device 20, and the image forming device 30 are connected in this order along the transport direction of the paper P.

[0020] The paper feeder 10 includes a plurality of paper feed trays 11 and a paper feed means (not shown), and feeds the paper P stored in the paper feed trays 11 to the paper condition detection device 20. The paper feed means includes, for example, a paper feed roller, a separation roller, a paper feed / separation rubber, a delivery roller, etc. Each paper feed tray 11 stores paper P according to the type of paper P (paper type, basis weight, paper size, etc.). The paper feeder 10 transports the paper P from the top of the paper P stored in each paper feed tray 11 to the paper condition detection device 20 one sheet at a time.

[0021] The paper state detection device 20 is connected to the rear stage of the paper feeder 10. The paper state detection device 20 includes a control unit 21, a first transport unit 22, a second transport unit 23, and a detection unit 24.

[0022] The control unit 21 has a CPU and memory, and controls the entire paper condition detection device 20. The CPU is a control circuit composed of a multi-core processor and the like that controls each of the above-mentioned parts and executes various types of calculation processing according to a program. Each function of the paper condition detection device 20 is realized by the CPU executing the corresponding program. The memory is a high-speed accessible main storage device that temporarily stores programs and data as a working area. For example, DRAM, SDRAM, SRAM, etc. are used as the memory.

[0023] The first conveying section 22 includes a first roller pair 221 and a drive section 222. The first roller pair 221 is made up of a pair of first rollers 221a, 221b that sandwich and convey the paper P. The drive section 222 is, for example, a motor, and drives and rotates the first roller pair 221. The first conveying section 22 sandwiches the paper P conveyed from the upstream side (the paper feeder 10 side) between the first roller pair 221 and conveys it downstream (the second conveying section 23 side).

[0024] The second conveying section 23 includes a second roller pair 231 and a drive section 232. The second conveying section 23 is disposed downstream of the first conveying section 22 in the conveying direction of the paper P. The second roller pair 231 is made up of a pair of second rollers 231a, 231b that sandwich and convey the paper P. The drive section 232 is, for example, a motor, and drives and rotates the second roller pair 231. The second conveying section 23 sandwiches the paper P conveyed from the upstream side (first conveying section 22 side) between the second roller pair 231 and conveys it downstream (image forming device 30 side). The first roller pair 221 and the second roller pair 231 are rotated by different driving units, and therefore the rotation speeds can be set individually.

[0025] The detection unit 24 is disposed between the first transport unit 22 and the second transport unit 23, and detects the state of the paper P. The detection unit 24 is, for example, a moisture sensor for detecting the moisture content of the paper P. The moisture content sensor irradiates LED light having a specific wavelength in a range of, for example, Φ30, and detects the moisture content of the paper P based on the reflectance from the paper surface. Therefore, if there is a tilt, wrinkle, or ripple in the detection range of the paper surface irradiated with the LED light, the reflectance changes, and the moisture content may be erroneously detected. The detection unit 24 may be a sensor that detects the edge of the paper P. The detection unit 24 may also be a sensor that detects a physical property (such as surface property) of the paper P other than the moisture content.

[0026] The image forming device 30 is connected to the rear stage of the paper condition detection device 20. The image forming device 30 includes a control unit 31, a storage unit 32, an image forming unit 33, an operation display unit 34, a conveying unit 35, and a communication unit 36. The image forming device 30 forms an image on the paper P whose paper condition has been detected by the paper condition detection device 20.

[0027] The control unit 31 has a CPU and a memory, and controls the entire image forming apparatus 30. The CPU is a control circuit composed of a multi-core processor and the like that controls each of the above-mentioned units and executes various arithmetic processing according to a program. Each function of the image forming apparatus 30 is realized by the CPU executing the corresponding program. The memory is a high-speed accessible main storage device that temporarily stores programs and data as a working area. For example, DRAM, SDRAM, SRAM, etc. are used as the memory.

[0028] The storage unit 32 is a large-capacity auxiliary storage device that stores various programs including an operating system and various data. For example, a hard disk, a solid state drive, a flash memory, a ROM, or the like is used as the storage.

[0029] The image forming unit 33 forms an image on the paper P conveyed from the paper state detection device 20 or on the paper P fed and conveyed from a paper feed tray 37 of the image forming unit 33. The image forming unit 33 forms an image on the paper P by using a well-known electrophotographic imaging process including, for example, the steps of charging, exposing, developing, transferring, and fixing.

[0030] The operation display unit 34 includes a touch panel, a numeric keypad, a start button, a stop button, etc., and is used to display various information and input various instructions. The user can set paper information such as the size and type of paper P stored in each paper feed tray 37 via the operation display unit 34.

[0031] The transport unit 35 includes a plurality of transport rollers and the like arranged on a transport path. The transport unit 35 first transports the paper P transported from the paper state detection device 20 or the paper P fed from a paper feed tray 37 of the transport unit 35 to the image forming unit 33. Next, the transport unit 35 discharges the paper P on which an image has been formed by the image forming unit 33 to a paper output tray 38.

[0032] The communication unit 36 ​​transmits and receives various information required for various setting values ​​and operation timing control between other devices (such as the paper feeder 10 and the paper state detection device 20).

[0033] Next, a detailed configuration of the paper condition detection device 20 will be described with reference to Fig. 3. In the figure, the X direction is the transport direction of the paper P, and the Y direction is the width direction of the paper P. The first contact width is the contact width when the first conveying section 22 contacts the paper surface of the paper P. The first contact width is the contact width of at least one of the pair of first rollers 221a, 221b. The contact width is the length in the width direction (Y direction) of the portion that contacts the paper surface. In the example shown in FIG. 3, since the first rollers 221a, 221b are cylindrical, the first contact width is the length in the width direction of each of the first rollers 221a, 221b. 3, the first contact width H12 of the lower first roller 221b is longer than the first contact width H11 of the upper first roller 221a. The first contact width H12 of the lower first roller 221b is longer than the width H3 of the detection range E of the detection unit 24. The width H3 of the detection range E is the length of the detection range E in the width direction. The detection unit 24 is disposed in the width direction of the paper P so that the detection range E falls within a first contact width H12 that is equal to or longer than the width H3 of the detection range E. Fig. 4 shows an example of a state in which sagging occurs in the paper P during transport in the configuration shown in Fig. 3. Fig. 4 shows a state in which sagging occurs in a range other than the vicinity of the detection range E of the paper P during transport. In other words, it can be seen that in the configuration shown in Fig. 3, sagging does not occur in the vicinity of the detection range E of the paper P during transport.

[0034] The first roller pair 221 and the second roller pair 231 are each arranged in a plurality (two in FIG. 3) intermittently in the width direction of the paper P. Note that, instead of arranging a plurality of roller pairs intermittently in the width direction, a cylindrical roller pair without any gaps in the width direction may be used as each roller pair. By using a cylindrical roller pair, the first contact width can reliably cover the width H3 of the detection range E of the detection unit 24. However, the configuration using the cylindrical roller pair has a problem that the risk of conveyance failure and wrinkles due to corner folding when the leading edge of the paper enters increases. In other words, the configuration using the cylindrical roller pair ultimately makes it difficult to stably detect the paper state. Therefore, in this embodiment, a plurality of roller pairs are arranged intermittently in the width direction. Note that the number of roller pairs arranged intermittently in the width direction in each roller pair may be three or more.

[0035] In addition, FIG. 3 illustrates a configuration in which the first contact width is equal to or greater than the width H3 of the detection range E of the detection unit 24, but is not limited thereto. For example, as shown in FIG. 5, the second contact width may be equal to or greater than the width H3 of the detection range E of the detection unit 24. In addition, FIG. 5(A) is a plan view showing a configuration in which the second contact width is equal to or greater than the width H3 of the detection range E. Also, FIG. 5(B) is a side view of the configuration shown in FIG. 5(A). The second contact width is the contact width when the second conveying unit 23 contacts the paper surface of the paper P. The second contact width is the contact width of at least one of the pair of second rollers 231a, 231b. In the example shown in FIG. 5, the second rollers 231a, 231b are cylindrical, so the second contact width is the width of each of the second rollers 231a, 231b. 5A, the second contact width H22 of the lower second roller 231b is longer than the second contact width H21 of the upper second roller 231a. The second contact width H22 of the lower second roller 231b is longer than the width H3 of the detection range E of the detection unit 24. The detection unit 24 is disposed in the width direction of the paper P so that the detection range E falls within a second contact width H22 that is equal to or longer than the width H3 of the detection range E.

[0036] The first contact width H12 and the second contact width H22 may both be longer than the width H3 of the detection range E of the detection unit 24. That is, any configuration may be used as long as at least one of the first contact width H12 and the second contact width H22 is longer than the width H3 of the detection range E. FIG. 6 shows an example of a configuration in which the first contact width H12 and the second contact width H22 are longer than the width H3 of the detection range E. FIG. 6(A) is a plan view showing a configuration in which the first contact width H12 and the second contact width H22 are longer than the width H3 of the detection range E. FIG. 6(B) is a side view of the configuration shown in FIG. 6(A).

[0037] The second transport section 23 is set so that the transport speed of the paper P is faster than that of the first transport section 22. That is, the transport speed V2 of the second transport section 23 is set faster than the transport speed V1 of the first transport section 22 (V2>V1). This allows the paper P to be transported while being pulled, thereby preventing the paper from bending in the transport direction. That is, even if the paper P tries to sag or twist under its own weight, the posture of the paper surface does not change, and the paper condition can be stably detected.

[0038] The detection unit 24 detects the paper condition of the paper P being transported. Specifically, the detection unit 24 detects the paper condition of the paper P being transported by at least one of the first transport unit 22 and the second transport unit 23.

[0039] As described above, the image forming system 1 according to the present embodiment includes the first transport section 22 and the second transport section 23 that transport the paper, and the detection section 24. The second transport section 23 is disposed downstream of the first transport section 22 in the paper transport direction. The detection section 24 is disposed between the first transport section 22 and the second transport section 23, and detects the paper state of the paper. At least one of the first contact width and the second contact width is longer than the width of the detection range of the detection section 24. The first contact width is the contact width when the first transport section 22 contacts the paper surface of the paper. The second contact width is the contact width when the second transport section 23 contacts the paper surface of the paper. The detection section 24 is disposed so that the detection range is within the contact width that is longer than the width of the detection range in the width direction of the paper. Therefore, according to the image forming system 1 of the present embodiment, it is possible to suppress the occurrence of paper bending, particularly in the width direction of the paper. This makes it possible to stabilize the paper posture, thereby reducing the detection variation of the paper state. Therefore, it is possible to detect the paper state with high accuracy.

[0040] The first transport section 22 also includes a first roller pair 221 consisting of a pair of first rollers 221a, 221b that sandwich and transport the paper. The first contact width is the contact width of at least one of the pair of first rollers 221a, 221b. Therefore, the occurrence of paper sagging can be suppressed with a simple configuration, and the paper position can be stabilized, so that the paper condition can be detected with high accuracy.

[0041] The second transport section 23 also includes a second roller pair 231 consisting of a pair of second rollers 231a, 231b that sandwich and transport the paper. The second contact width is the contact width of at least one of the pair of second rollers 231a, 231b. Therefore, the occurrence of paper sagging can be suppressed with a simple configuration, and the paper position can be stabilized, so that the paper condition can be detected with high accuracy.

[0042] Further, the second transport section 23 transports the paper at a faster speed than the first transport section 22. Therefore, since the paper can be transported while being pulled, it is possible to prevent the paper from sagging in the transport direction, and therefore the paper condition can be detected stably.

[0043] Furthermore, the detection unit 24 detects the physical properties of the paper. The physical properties of paper are easily affected by the paper position when they are detected. Therefore, even in a configuration that is easily affected by the paper position, the paper position can be stabilized. Therefore, even in a configuration that is easily affected by the paper position, the paper condition can be detected with high accuracy.

[0044] Further, the detection unit 24 detects the state of the paper being conveyed. The paper position is easily disturbed during transport. Therefore, even in a situation where the paper position is easily disturbed, the paper position can be stabilized. Therefore, even in a situation where the paper position is easily disturbed, the paper state can be detected with high accuracy.

[0045] Although the present invention has been specifically described above based on an embodiment thereof, the present invention is not limited to the above embodiment and can be modified without departing from the spirit of the present invention.

[0046] For example, in the above embodiment, the first contact width H12 of the lower first roller 221b is set to a length equal to or greater than the width H3 of the detection range E of the detection unit 24, but is not limited to this. For example, the first contact width H11 of the upper first roller 221a may be set to a length equal to or greater than the width H3 of the detection range E of the detection unit 24. However, because the paper P tends to sag downward due to its own weight, it is more preferable to set the first contact width H12 of the lower first roller 221b to a length equal to or greater than the width H3 of the detection range E. By setting the first contact width H12 of the lower first roller 221b to a length equal to or greater than the width H3 of the detection range E, the posture of the paper P can be stabilized more reliably.

[0047] In the above embodiment, the first contact width is the contact width of at least one of the pair of first rollers 221a, 221b, but is not limited thereto. For example, the first contact width may be the contact width of all the first rollers 221a, 221b forming the first roller pair 221. That is, the first contact width H1 is the first contact width H12 of the lower first roller 221b and the first contact width H11 of the upper first roller 221a. FIG. 7 shows an example of a configuration in which the first contact width H1 is the contact widths H11, H12 of all the first rollers 221a, 221b forming the first roller pair 221. FIG. 7(A) is a plan view showing a configuration in which the first contact width H1 is the contact widths H11, H12 of all the first rollers 221a, 221b forming the first roller pair 221. FIG. 7(B) is a side view of the configuration shown in FIG. 7(A). As described above, the paper posture can be stabilized more reliably by setting the first contact width to the contact width of all first rollers 221a, 221b forming first roller pair 221. This makes it possible to detect the paper state with high accuracy.

[0048] 5, the second contact width H22 of the lower second roller 231b is set to a length equal to or greater than the width H3 of the detection range E of the detection unit 24, but is not limited to this. For example, the second contact width H21 of the upper second roller 231a may be set to a length equal to or greater than the width H3 of the detection range E of the detection unit 24. However, since the paper P tends to sag downward due to its own weight, it is more preferable to set the second contact width H22 of the lower second roller 231b to a length equal to or greater than the width H3 of the detection range E. By setting the second contact width H22 of the lower second roller 231b to a length equal to or greater than the width H3 of the detection range E, the posture of the paper P can be stabilized more reliably.

[0049] In the example shown in FIG. 5, the second contact width is the contact width of at least one of the pair of second rollers 231a, 231b, but is not limited thereto. For example, the second contact width may be the contact width of all second rollers 231a, 231b forming the second roller pair 231. That is, the second contact width H2 is the second contact width H22 of the lower second roller 231b and the second contact width H21 of the upper second roller 231a. FIG. 8 shows an example of a configuration in which the second contact width H2 is the contact widths H21, H22 of all second rollers 231a, 231b forming the second roller pair 231. FIG. 8(A) is a plan view showing a configuration in which the second contact width H2 is the contact widths H21, H22 of all second rollers 231a, 231b forming the second roller pair 231. FIG. 8(B) is a side view of the configuration shown in FIG. 8(A). As described above, the paper posture can be stabilized more reliably by setting the second contact width to the contact width of all second rollers 231a, 231b forming the second roller pair 231. This makes it possible to detect the paper state with high accuracy.

[0050] Also, the contact width of all rollers forming the first roller pair 221 and the second roller pair 231 may be set to be equal to or greater than the width H3 of the detection range E of the detection unit 24. This makes it possible to further stabilize the paper posture, and therefore to detect the paper condition with high accuracy.

[0051] In addition, the detailed configurations and operations of each device constituting the image forming system may be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0052] 1. Image forming system 10 Paper feeder 11 Paper feed tray 20 Paper condition detection device 21 Control section 22 First conveyor section 221 First Roller Pair 221a, 221b First roller 222 Drive unit 23 Second conveyor section 231 Second Roller Pair 231a, 231b Second roller 232 Drive unit 24 Detection unit 30 Image forming device 31 Control Unit 32 Storage section 33 Image forming section 34 Operation display section 35 Conveyor 36 Communications Department 37 Paper feed tray 38 Output tray P paper

Claims

1. A first conveying unit that conveys paper; a second transport section disposed downstream of the first transport section in a transport direction of the paper and configured to transport the paper; a detection unit disposed between the first transport unit and the second transport unit and configured to detect a paper state of the paper; Equipped with at least one of a first contact width, which is a contact width when the first transport unit contacts the paper surface of the paper, and a second contact width, which is a contact width when the second transport unit contacts the paper surface of the paper, is equal to or greater than the width of the detection range of the detection unit; The paper condition detection device, wherein the detection unit is disposed in a width direction of the paper such that the detection range falls within the contact width, the contact width being equal to or greater than the width of the detection range.

2. the first transport section includes a first roller pair including a pair of first rollers that sandwich and transport the paper; 2 . The sheet condition detection device according to claim 1 , wherein the first contact width is the contact width of at least one of the pair of first rollers.

3. the second transport section includes a second roller pair including a pair of second rollers that sandwich and transport the paper; 2 . The sheet condition detection device according to claim 1 , wherein the second contact width is the contact width of at least one of the pair of second rollers.

4. 3. The paper condition detection device according to claim 2, wherein the first contact width is a contact width of all the first rollers that form the first roller pair.

5. 4. The paper condition detection device according to claim 3, wherein the second contact width is a contact width of all the second rollers forming the second roller pair.

6. 2. The paper condition detection device according to claim 1, wherein the second transport section transports the paper faster than the first transport section.

7. The paper condition detection device according to claim 1 , wherein the detection unit detects a physical property of the paper.

8. 2. The paper condition detection device according to claim 1, wherein the detection section detects the paper condition of the paper being conveyed.

9. A paper state detection device according to any one of claims 1 to 8, an image forming apparatus for forming an image on the paper whose paper state has been detected by the paper state detection device; An image forming system comprising:

Images