Image forming system, control method, and control program

Abstract

To prevent shortening of the life of a detection unit that detects the characteristics of a sheet, or prevent a reduction in the productivity of the detection unit.SOLUTION: An image forming system 100 comprises: an image forming unit 38 that forms images on a recording medium (sheet); a first characteristic detection unit 23 that is provided on the upstream side of the image forming unit 38 in the conveyance direction of the recording medium, and detects characteristic information corresponding to the characteristics of the recording medium; and second characteristic detection units 42, 53 that are provided on the downstream side of the image forming unit 38 in the conveyance direction of the recording medium, and detects the characteristic information. On the basis of a result of detection performed by any one characteristic detection unit of the first characteristic detection unit 23 and the second characteristic detection unit 42, the other characteristic detection unit is controlled. Alternatively, on the basis of a result of detection performed by any one characteristic detection unit of the first characteristic detection unit 23 and the second characteristic detection unit 53, the other characteristic detection unit is controlled.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] When printing on paper using an image forming apparatus such as a copier or printer, the characteristics of the paper and the environment within the apparatus change before and after printing, particularly before and after mass printing. In this regard, for example, Patent Document 1 describes the following image forming device. Specifically, the device is capable of forming images on both sides of a sheet of paper and is equipped with multiple detection units that detect the characteristics of the sheet on the sheet transport path. The device corrects the image to be printed on the back side of the sheet of paper based on the expansion and contraction rate of the sheet calculated from the temperature and moisture content of the sheet before and after printing on the front side of the sheet detected by the detection units.

[0003] In this manner, by controlling the image forming conditions based on the detection results from a plurality of detection units provided on the paper transport path, more appropriate image forming conditions can be set. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-45740 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the detection unit that detects the characteristics of the paper gradually deteriorates depending on the number of detections. For example, a case will be described in which the detection unit includes a light-emitting element such as an LED (Light Emitting Diode) as a light-emitting unit. In this case, the light-emitting element gradually deteriorates depending on the number of detections, and when the light-emitting element deteriorates, the detection unit cannot accurately detect the characteristics of the paper. In addition, the detection operation by the detection unit is a highly accurate and complicated process compared to paper detection for normal paper transport, and therefore, depending on the characteristics of the paper to be detected, it may be necessary to stop the paper when the detection unit detects the characteristics of the paper in order to ensure detection accuracy, which may reduce productivity.

[0006] An object of the present invention is to provide an image forming system, a control method, and a control program that can prevent a decrease in productivity or a shortened life of a detection unit that detects paper characteristics. [Means for solving the problem]

[0007] In order to solve the above problem, the image forming system according to claim 1 comprises: an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; Equipped with Based on a detection result of either the first characteristic detection unit or the second characteristic detection unit, the other characteristic detection unit is controlled.

[0008] The invention described in claim 2 is the image forming system described in claim 1, The second characteristic detection section is controlled based on a detection result of the first characteristic detection section.

[0009] The invention described in claim 3 is the image forming system described in claim 1, The characteristic information is information corresponding to at least one of the moisture content, resistance, and stiffness of the recording medium.

[0010] The invention described in claim 4 is the image forming system described in claim 1, The device further includes a control unit that controls the second characteristic detection unit based on a detection result of the first characteristic detection unit.

[0011] The invention described in claim 5 is the image forming system described in claim 4, The control unit calculates a shrinkage rate of the recording medium based on detection results of the first characteristic detection unit and the second characteristic detection unit.

[0012] The invention described in claim 6 is the image forming system described in claim 4, The control unit controls image forming conditions of the image forming unit based on a shrinkage rate of the recording medium.

[0013] The invention described in claim 7 is the image forming system described in claim 4, The control unit controls the second characteristic detection unit not to perform detection in accordance with a detection result of the first characteristic detection unit.

[0014] The invention described in claim 8 is the image forming system described in claim 7, The control unit controls the second characteristic detection unit not to perform detection when a detection result of the first characteristic detection unit is equal to or less than a predetermined threshold value.

[0015] The invention described in claim 9 is the image forming system described in claim 8, the characteristic information is information corresponding to a moisture content of the recording medium, The control unit controls the second characteristic detection unit not to perform detection when information corresponding to the moisture amount detected by the first characteristic detection unit is equal to or smaller than a predetermined threshold value.

[0016] The invention described in claim 10 is the image forming system described in claim 4, The control unit changes a detection method used by the second characteristic detection unit according to a detection result of the first characteristic detection unit.

[0017] The invention described in claim 11 is the image forming system described in claim 10, the characteristic information is information corresponding to a moisture content of the recording medium, The control unit changes a detection method used by the second characteristic detection unit in accordance with information corresponding to the moisture amount detected by the first characteristic detection unit.

[0018] The invention described in claim 12 is the image forming system described in claim 10, The control unit changes the frequency of detection by the second characteristic detection unit as the change in the detection method.

[0019] The invention described in claim 13 is the image forming system described in claim 12, The control unit changes the detection position on the recording medium detected by the second characteristic detection unit as the change in the detection method.

[0020] The invention described in claim 14 is the image forming system described in claim 10, the first characteristic detection unit and the second characteristic detection unit are capable of detecting the characteristic information on one recording medium a plurality of times; The control unit changes the number of times the second characteristic detection unit detects one recording medium, as the change in the detection method.

[0021] The invention described in claim 15 is the image forming system described in claim 14, The control unit reduces the number of detections by the second characteristic detection unit to less than a predetermined number of detections when a variation in the results of multiple detections by the first characteristic detection unit is equal to or smaller than a predetermined value.

[0022] The invention described in claim 16 is the image forming system described in claim 14, The control unit reduces the number of detections by the second characteristic detection unit to less than a predetermined number of detections when all of the multiple detection results by the first characteristic detection unit are equal to or less than a predetermined threshold value.

[0023] The control method according to claim 17 comprises: an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; A control method for an image forming system comprising: Based on a detection result of either the first characteristic detection unit or the second characteristic detection unit, the other characteristic detection unit is controlled.

[0024] The control program according to claim 18, an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; A computer of an image forming system comprising: Based on a detection result of either one of the first characteristic detection unit and the second characteristic detection unit, the other characteristic detection unit is caused to function as a control unit. Effect of the Invention

[0025] According to the present invention, it is possible to prevent a decrease in the life span of a detection unit that detects paper characteristics or a decrease in productivity. [Brief description of the drawings]

[0026] [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] 1 is a block diagram showing a main functional configuration of an image forming system according to an embodiment of the present invention; [Diagram 3]2 is a diagram illustrating an example of a schematic configuration of a first characteristic detection unit. [Figure 4] 6 is a flowchart showing a flow of a detection control process executed by the image forming system. [Diagram 5] FIG. 13 is a diagram showing a schematic configuration of an image forming system according to a first modified example. [Figure 6] FIG. 13 is a block diagram showing a main functional configuration of an image forming system according to a first modified example. [Figure 7] 13 is a flowchart showing the flow of a detection control process executed by the image forming system of the first modified example. [Figure 8] 13 is a flowchart showing the flow of a detection control process executed by an image forming system according to a second modified example. [Figure 9] 13 is a flowchart showing the flow of a detection control process executed by the image forming system of Modification 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the image forming system of the present invention will be described with reference to the drawings. Note that in the embodiment of the present invention, the image forming device provided in the image forming system will be described as a system color image forming device, but the present invention is not limited to this and can also be applied to, for example, a monochrome image forming device.

[0028] (1. Configuration of Image Forming System) Fig. 1 is a diagram showing a schematic configuration of an image forming system 100 according to this embodiment. Fig. 2 is a block diagram showing a main functional configuration of the image forming system 100. The image forming system 100 forms an image made up of multiple colors on a recording medium. The recording medium is not particularly limited, and any known medium can be used. For example, in addition to paper such as plain paper or coated paper, various media capable of fixing a coloring material attached to the surface, such as sheet-shaped resin, can be used. Hereinafter, the recording medium is assumed to be paper.

[0029] The image forming system 100 according to this embodiment includes a paper feeder 10, a first detection device 20, an image forming device 30, a second detection device 50, and a paper discharge device 60. In the image forming system 100, a paper feeder 10, a first detection device 20, an image forming device 30, a second detection device 50, and a paper discharge device 60 are arranged in this order from the upstream side along the paper transport direction.

[0030] (1-1. Configuration of the paper feeder) The paper feeding device 10 includes a first control unit 11, a transport unit 12, a paper feeding unit 13, and the like. The first control unit 11 is connected to the transport unit 12 and the paper feed unit 13 via a bus 14 .

[0031] The first control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU of the first control unit 11 reads out a program stored in the ROM, loads it into the RAM, and generally controls each unit of the sheet feeding device 10 according to the loaded program. For example, the first control unit 11 conveys a sheet from one of the sheet feed trays of the sheet feed unit 13 to the first detection device 20 depending on the job.

[0032] The transport unit 12 transports the paper through a transport path that connects the paper feed unit 13 to the first detection device 20 . The paper feed unit 13 has paper feed trays that store paper according to predetermined paper types and sizes.

[0033] (1-2. Configuration of the first detection device) The first detector 20 is provided upstream of the image forming device 30 in the paper transport direction, and detects the characteristics of the paper transported from the paper feeder 10. The first detection device 20 includes a second control unit 21, a transport unit 22, and a first characteristic detection unit . The second control unit 21 is connected to the transport unit 22 and the first characteristic detection unit 23 via a bus 24.

[0034] The second control unit 21 includes a CPU, a ROM, and a RAM. The CPU of the second control unit 21 reads out a program stored in the ROM, loads it into the RAM, and generally controls each part of the first detection device 20 according to the loaded program. For example, the second control unit 21 causes the first characteristic detection unit 23 to detect the paper conveyed from the paper feeder 10. Next, the second control unit 21 causes the conveying unit 22 to convey the detected paper to the image forming device 30.

[0035] The transport section 22 includes a plurality of roller pairs, and transports the paper transported from the paper feeder 10 to the first characteristic detection section 23. Next, the conveying unit 22 conveys the paper detected by the first characteristic detecting unit 23 to the image forming device 30.

[0036] The first characteristic detection unit 23 is provided on the transport path upstream in the paper transport direction of an image forming unit 38 (described later) of the image forming apparatus 30. The first characteristic detection unit 23 detects the moisture content of the paper as a characteristic of the paper before an image is formed by the image forming unit 38. FIG. 3 is a schematic diagram showing the configuration of the first characteristic detection section 23. As shown in FIG.

[0037] As shown in FIG. 3, the first characteristic detection unit 23 includes a first light-emitting unit 231, a second light-emitting unit 232, a light-receiving unit 233, lenses 234 and 235, and the like.

[0038] The first light-emitting unit 231 emits first near-infrared light (reference light) in a specific wavelength band toward the paper P. A specific example of the first light-emitting unit 231 is an LED or the like. The first near-infrared light is light whose absorptance in the paper P when reflected by the paper P does not depend on the moisture content of the paper P. The light receiving section 233 receives, via a lens 235, the first near-infrared light that is emitted from the first light emitting section 231 and reflected by the paper P via a lens 234. Specific examples of the light receiving unit 233 include a CCD (Charge-Coupled Device) and a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor.

[0039] The second light-emitting unit 232 emits second near-infrared light in a specific wavelength band toward the paper P. A specific example of the second light-emitting unit 232 is an LED or the like. The second near-infrared light is light whose absorptance in the paper P when reflected by the paper P varies depending on the moisture content of the paper P. The light receiving section 233 receives, via a lens 235, the second near-infrared light that is emitted from the second light emitting section 232 and reflected by the paper P via a lens 234.

[0040] The first characteristic detection unit 23 detects the moisture content of the paper P based on the ratio between the amount of the first near-infrared light received by the light receiving unit 233 and the amount of the second near-infrared light received. The second control unit 21 outputs the moisture amount of the paper sheet P detected by the first characteristic detection unit 23 (the first moisture amount) to the third control unit 31. The configuration of the first characteristic detection unit 23 is not limited to the example shown in Fig. 3. The first characteristic detection unit 23 may have another configuration as long as it can detect the moisture content of the paper P.

[0041] (1-3. Configuration of Image Forming Apparatus) The image forming apparatus 30 forms a color image by electrophotography based on image data obtained by reading an image from an original or image data of a job received from an external device. The image forming apparatus 30 includes a third control unit 31, a memory unit 32, an operation unit 33, a display unit 34, an interface 35, a scanner 36, an image processing unit 37, an image forming unit 38, an image fixing unit 39, a conveying unit 40, and the like. The third control unit 31 is connected to the memory unit 32, the operation unit 33, the display unit 34, the interface 35, the scanner 36, the image processing unit 37, the image forming unit 38, the image fixing unit 39, and the transport unit 40 via a bus 41.

[0042] The third control unit 31 includes a CPU, a ROM, and a RAM. The CPU of the third control unit 31 reads out a control program stored in the ROM, loads it into the RAM, and generally controls each unit of the image forming apparatus 30 according to the loaded program. For example, the third control unit 31 causes the image processing unit 37 to perform a predetermined image processing on the image data and stores the image data in the memory unit 32. Next, the third control unit 31 causes the conveying unit 40 to convey the paper and causes the image forming unit 38 to form an image on the paper based on the image data stored in the memory unit 32.

[0043] The storage unit 32 includes a semiconductor memory such as a DRAM or a HDD. The storage unit 32 stores image data acquired by the scanner 36, image data input from the outside via the interface 35, etc. These image data, etc. may be stored in a RAM included in the third control unit 31.

[0044] The operation unit 33 includes an input device such as an operation key and a touch panel arranged over the screen of the display unit 34 . The operation unit 33 converts input operations on these input devices into operation signals and outputs them to the third control unit 31.

[0045] The display unit 34 includes a display device such as an LCD (Liquid Crystal Display), and displays an operation screen showing the state of the image forming system 100 and the contents of input operations to a touch panel.

[0046] The interface 35 transmits and receives data to and from an external computer, another image forming apparatus, and the like. The interface 35 may comprise, for example, any of a variety of serial interfaces.

[0047] The scanner 36 reads an image formed on a sheet of paper, generates image data including monochromatic image data for each of the color components R (red), G (green), and B (blue), and stores the image data in the storage unit 32 .

[0048] The image processing unit 37 includes, for example, a rasterization processing unit, a color conversion unit, a tone correction unit, and a halftone processing unit. The image processing unit 37 performs various image processes on the image data stored in the storage unit 32 and stores the processed image data in the storage unit 32 .

[0049] The image forming unit 38 forms an image on a sheet based on the image data stored in the storage unit 32 . The image forming unit 38 includes four sets of exposure units 381, photoconductor drums 382, ​​and developing units 383, each set corresponding to a color component of C (cyan), M (magenta), Y (yellow), and K (black). The image forming unit 38 includes a transfer body 384 and a secondary transfer roller 385.

[0050] The exposure section 381 includes an LD (Laser Diode) as a light emitting element. The exposure unit 381 drives the LD based on image data, and irradiates a charged photoconductor drum 382 with laser light to expose the photoconductor drum 382 and form an electrostatic latent image on the photoconductor drum 382 . The developing unit 383 supplies toner (color material) of a predetermined color by a charging developing roller onto the exposed photoconductor drum 382, ​​thereby developing the electrostatic latent image formed on the photoconductor drum 382. The predetermined color is any one of C, M, Y, and K.

[0051] The image forming unit 38 sequentially transfers images (monochrome images) formed with C, M, Y, and K toners on the four photoconductor drums 382 from each photoconductor drum 382 onto the transfer body 384 in a superimposed manner. In this way, the image forming unit 38 forms a color image having C, M, Y, and K as color components on the transfer body 384. The transfer body 384 is an endless belt wound around a plurality of transfer body transport rollers, and rotates in accordance with the rotation of each transfer body transport roller.

[0052] Secondary transfer roller 385 transfers the color image on transfer body 384 onto paper fed from paper feeder 10. More specifically, a transfer nip formed by pressure contact between a pair of secondary transfer rollers 385 sandwiches the paper and transfer body 384. Furthermore, image forming unit 38 applies a predetermined transfer voltage to secondary transfer roller 385. As a result, image forming unit 38 transfers the color image formed on transfer body 384 onto the paper.

[0053] The image fixing unit 39 includes a fixing roller, a pressure roller, and the like, and performs a fixing process of applying heat and pressure to the paper onto which the color image has been transferred, thereby fixing the color image onto the paper.

[0054] The transport section 40 includes a plurality of paper transport rollers that rotate while clamping the paper to transport the paper, and transports the paper along a predetermined transport path. The transport unit 40 includes a reversing mechanism 401 that reverses the paper on which the image fixing unit 39 has performed the fixing process and transports the paper to the secondary transfer roller 385 . When forming images on both sides of the paper, the transport unit 40 inverts the paper using the inversion mechanism 401 and discharges the paper after images have been formed on both sides. When forming images on only one side of the paper, the transport unit 40 does not invert the paper using the inversion mechanism 401 and discharges the paper with the image formed on one side.

[0055] (1-4. Configuration of the second detection device) The second detection device 50 is provided downstream of the image forming device 30 in the paper transport direction, and detects the paper transported from the image forming device 30. The second detection device 50 includes a fourth control unit 51, a transport unit 52, and a second characteristic detection unit 53. The fourth control unit 51 is connected to the transport unit 52 and the second characteristic detection unit 53 via a bus 54. The fourth control unit 51, the transport unit 52, and the second characteristic detection unit 53 have the same configurations as the second control unit 21, the transport unit 22, and the first characteristic detection unit 23, respectively, and therefore their explanations are omitted.

[0056] The second characteristic detection unit 53 is provided on the transport path downstream in the paper transport direction from the image forming unit 38. The second characteristic detection unit 53 detects the moisture content of the paper as a characteristic of the paper after an image is formed by the image forming unit 38. The moisture content of the sheet P detected by the second characteristic detection unit 53 is the second moisture content.

[0057] (1-5. Configuration of the paper discharge device 60) The paper discharge device 60 is provided downstream of the second detection device 50 in the paper transport direction, and discharges the paper transported from the second detection device 50. The paper discharge device 60 includes a fifth control unit 61, a transport unit 62, a first tray 63, a second tray 64, and the like. The fifth control unit 61 is connected to the transport unit 62 via a bus 65 .

[0058] The fifth control unit 61 includes a CPU, a ROM, and a RAM. The CPU of the fifth control unit 61 reads out a program stored in the ROM, loads it into the RAM, and generally controls each part of the paper discharge device 60 according to the loaded program.

[0059] The transport section 62 includes a plurality of roller pairs. Under the control of the fifth control unit 61, the conveying unit 62 conveys the paper conveyed from the second detection device 50 to the first tray 63 or the second tray 64.

[0060] In this embodiment, the third control unit 31 of the image forming device 30 centrally controls the entire image forming system 100, but this is not limited thereto. The second control unit 21 of the first detection device 20 or the fourth control unit 51 of the second detection device 50 may centrally control the entire image forming system 100.

[0061] (2. Operation of the Image Forming System) Next, the operation of the image forming system 100 will be described. The third control unit 31 of the image forming apparatus 30 executes a detection control process when image data and setting information of a print job are received via the operation unit 33 or the interface 35 . FIG. 4 is a flowchart showing the flow of the detection control process. The CPU of the third control unit 31 of the image forming apparatus 30 executes the detection control process in cooperation with a control program stored in the ROM.

[0062] (2-1. Detection control processing) The third control unit 31 causes the sheet feeding device 10 to feed a sheet of paper, on which an image is to be formed in the print job, from the sheet feeding unit 13, and conveys the sheet of paper to the first detection device 20 (step A1).

[0063] Next, the third control section 31 causes the first characteristic detection section 23 to detect a first moisture content of the paper on the transport path that was fed in step A1 (step A2). Next, the third control section 31 causes the image forming section 38 to form a job image of the print job on the front side of the paper fed in step A1 (step A3).

[0064] Next, the third control unit 31 judges whether the first moisture amount detected in step A2 is equal to or less than a predetermined threshold value (step A4). The predetermined threshold value is set in advance. When the first moisture content is equal to or less than the predetermined threshold, it is estimated that the moisture content of the paper does not change before and after the image formation process by the image forming unit 38. This is the case, for example, when the moisture content of the paper is small before the image formation process, and therefore the moisture content of the paper is unlikely to change even after the fixing process is performed. In this case, the paper is unlikely to shrink even after the image formation process and the fixing process are performed.

[0065] A case where the first moisture amount is greater than the predetermined threshold value (step A4; NO) will be described. In this case, the third control unit 31 determines whether or not the second moisture amount detected when the image was formed previously (the previous second moisture amount) is stored in the memory unit 32 (step A5).

[0066] The case where the previous second moisture content is stored (step A5; YES) will be described below. In this case, the third control unit 31 calculates the shrinkage rate of the paper before and after forming images on both sides of the paper based on the current first moisture content detected in step A2 and the previous second moisture content (step A6). Next, the third control section 31 changes the image forming conditions for the back surface of the paper based on the shrinkage rate of the paper calculated in step A6 (step A7). Next, the third control section 31 uses the image forming conditions changed in step A7 to cause the image forming section 38 to form a job image of the print job on the back side of the paper fed in step A1 (step A8).

[0067] Next, the third control section 31 judges whether or not formation of images for the number of prints (predetermined number of prints) set in the print job has been completed (step A11). When the formation of the predetermined number of images is completed (step A11; YES), the third control section 31 ends this process.

[0068] If the formation of the predetermined number of images has not been completed (step A11; NO), the third control section 31 shifts the process to step A1.

[0069] A case where the previous second moisture content is not stored (step A5; NO) will be described. In this case, the third control unit 31 causes the image forming unit 38 to form a job image of the print job on the back side of the paper fed in step A1 (step A10). Next, the third control section 31 causes the second characteristic detection section 53 to detect the second moisture amount of the paper after the image has been formed on the back surface in step A10 (step A11). Next, the third control unit 31 stores the second moisture content detected in step A11 in the storage unit 32 (step A12), and transitions the process to step A9.

[0070] A case where the first moisture content is equal to or less than the predetermined threshold value (step A4; YES) will be described. In this case, the third control unit 31 causes the image forming unit 38 to form a job image of the print job on the back side of the paper fed in step A1 (step A13), and the process proceeds to step A9.

[0071] In step A5 of the detection control process, the third control unit 31 may determine whether or not the second moisture amount detected when an image is formed in the currently executing print job is stored in the memory unit 32. A case will be described in which the second moisture amount detected when forming an image in the currently executed print job is stored. In this case, the third control unit 31 calculates the shrinkage rate of the paper before and after forming an image on both sides of the paper based on the current first moisture amount detected in step A2 and the second moisture amount detected in the currently executed print job.

[0072] As described above, when the detection result of first characteristic detection unit 23 is equal to or lower than a predetermined threshold, third control unit 31 controls so as not to perform detection by second characteristic detection unit 53. The detection result of first characteristic detection unit 23 is information corresponding to the amount of moisture detected by first characteristic detection unit 23. This can reduce the number of detections by second characteristic detector 53. That is, the number of times the light emitting unit emits light to detect the moisture content can be reduced, and the life of the light emitting unit can be extended.

[0073] As described above, the third control unit 31 executes the detection control process to control the second characteristic detection unit 53 based on the detection result of the first characteristic detection unit 23. The third control unit 31 functions as a control unit.

[0074] (3. Modifications) (3-1. Variation 1) Next, a description will be given of Modification 1 of the present invention. In Modification 1, the same components as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted. Fig. 5 is a diagram showing a schematic configuration of an image forming system 100 of this modified example. Fig. 6 is a block diagram showing a main functional configuration of the image forming system 100 of this modified example.

[0075] In this modification, the image forming system 100 does not include the second detection device 50, but the image forming apparatus 30 includes a second characteristic detection unit . The second characteristic detection unit 42 is disposed downstream of the image fixing unit 39 in the paper transport direction and upstream of the leading edge position of the paper when the image forming unit 38 starts exposing the back side image. The back side image is an image formed on the back side of the paper. In other words, the second characteristic detection unit 42 is disposed on the re-feed path 402 of the transport unit 40 and upstream of the registration roller pair 403 of the transport unit 40 in the paper transport direction. FIG. 7 is a flowchart showing the flow of the detection control process of this modified example.

[0076] (Detection control process of modification 1) The third control unit 31 performs steps B1 to B4 similar to the detection control processing steps A1 to A4 of the above embodiment. A case where the first moisture content is greater than the predetermined threshold value (step B4; NO) will be described. In this case, the third control unit 31 causes the second characteristic detection unit 42 to detect the second moisture content of the paper after the image is formed on the front surface of the paper in step B3 (step B5).

[0077] Next, the third control unit 31 calculates the shrinkage rate of the paper before and after forming an image on the surface of the paper based on the first moisture amount detected in step B2 and the second moisture amount detected in step B5 (step B6). Next, the third control unit 31 performs steps B7 to B9 similar to the detection control processing steps A7 to A9 of the above embodiment.

[0078] If the first moisture amount is equal to or less than the predetermined threshold value (step B4; YES), the third control unit 31 transitions the process to step B8.

[0079] In other words, when the detection result of first characteristic detection unit 23 is equal to or lower than a predetermined threshold, third control unit 31 controls so as not to perform detection by second characteristic detection unit 42. The detection result of first characteristic detection unit 23 is information corresponding to the amount of moisture detected by first characteristic detection unit 23. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0080] (3-2. Variation 2) Next, a description will be given of Modification 2 of the present invention. In Modification 2, the same components as those in Modification 1 of the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The configuration of the image forming system 100 of the second modification is similar to the configuration of the image forming system 100 of the first modification. FIG. 8 is a flowchart showing the flow of the detection control process of this modified example.

[0081] (Detection control process of modified example 2) The third control section 31 performs step C1 similar to the detection control process step B1 of the first modification example. Next, the third control section 31 causes the first characteristic detection section 23 to detect the first moisture amount five times in the sheet of paper on the transport path that was fed in step C1 (step C2). In step C2, the third control unit 31 detects the first moisture amount at different positions on a sheet of paper, such as the leading edge, the center, and the trailing edge of the sheet. Next, the third control section 31 performs step C3, which is the same as step B3 of the detection control process in the first modification example.

[0082] Next, the third control unit 31 determines whether or not the average value of the first moisture content detected five times in step C2 is equal to or less than a predetermined threshold value (step C4). The case where the average value of the first moisture content is greater than the predetermined threshold value (step C4; NO) will be described. In this case, the third control unit 31 determines whether the difference between the maximum value and the minimum value of the first moisture content detected five times in step C2 is equal to or less than a predetermined value (step C5). The predetermined value is set in advance.

[0083] A case where the difference between the maximum and minimum values ​​of the first moisture content is greater than the predetermined value (step C5; NO) will be described below. In this case, the third control unit 31 causes the second characteristic detection unit 42 to detect the second moisture content of the paper five times after the image is formed on the front surface of the paper in step C3 (step C6). In step C6, the third control unit 31 detects the second moisture amount at different positions on a sheet of paper, such as the leading edge, the center, and the trailing edge of the sheet.

[0084] Next, the third control unit 31 calculates the shrinkage rate of the paper before and after forming an image on the surface of the paper based on the average value of the first moisture content detected in step C2 and the average value of the second moisture content detected in step C6 (step C7). Next, the third control unit 31 performs steps C8 to C10 similar to steps B7 to B9 of the detection control process of the first modification.

[0085] A case where the difference between the maximum and minimum values ​​of the first moisture content is equal to or less than a predetermined value (step C5; YES) will be described. In this case, the third control unit 31 causes the second characteristic detection unit 42 to detect once (step C11) the second moisture content of the paper after the image is formed on the front surface of the paper in step C3.

[0086] That is, when the variation in the results of multiple detections by the first characteristic detector 23 is equal to or smaller than a predetermined value, the third control unit 31 causes the number of detections by the second characteristic detector 42 to be less than a predetermined number of detections. When the variation in the results of detection performed multiple times by the first characteristic detector 23 is equal to or less than a predetermined value, it is estimated that the variation in the results of detection performed by the second characteristic detector 42 is also small. Therefore, it is not necessary to perform detection by the second characteristic detector 42 multiple times. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0087] Next, the third control unit 31 calculates the shrinkage rate of the paper before and after forming an image on the surface of the paper based on the average value of the first moisture amount detected in step C2 and the second moisture amount detected in step C11 (step C12). Next, the third control unit 31 shifts the process to step C8.

[0088] When the first moisture content average value is equal to or less than the predetermined threshold value (step C4; YES), the third control unit 31 shifts the process to step C9.

[0089] In other words, the third control unit 31 controls so as not to perform detection by the second characteristic detection unit 42 when the detection result of the first characteristic detection unit 23 is equal to or lower than a predetermined threshold. The detection result of the first characteristic detection unit 23 is information corresponding to the amount of moisture detected by the first characteristic detection unit 23. Specifically, the detection result of the first characteristic detection unit 23 is the average value of the amount of moisture detected by the first characteristic detection unit 23. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0090] (3-3. Variation 3) Next, a description will be given of Modification 3 of the present invention. In Modification 3, the same components as those in Modification 2 of the above embodiment are given the same reference numerals, and the description thereof will be omitted. The configuration of the image forming system 100 of the third modification is similar to the configuration of the image forming system 100 of the first modification. FIG. 9 is a flowchart showing the flow of the detection control process of this modified example.

[0091] (Detection control process of modified example 3) The third control unit 31 performs steps D1 to D3 similar to the detection control process steps C1 to C3 of the second modification.

[0092] Next, the third control unit 31 determines whether or not all of the first moisture amounts detected five times in step D2 are equal to or less than a predetermined threshold value (step D4). A case will be described where any of the first moisture amounts detected five times in step D2 is greater than a predetermined threshold value (step D4; NO). In this case, the third control unit 31 performs steps D5 to D9 similar to the detection control process steps C6 to C10 in the above modification 2.

[0093] A case where all of the first moisture amounts detected five times in step D2 are equal to or less than the predetermined threshold value (step D4; YES) will be described. In this case, the third control unit 31 performs steps D10 and D11 similar to the detection control process steps C11 and C12 in the above modification 2, and then transitions to step D7.

[0094] In other words, when the multiple detection results by the first characteristic detector 23 are all equal to or less than the predetermined value, the third control unit 31 reduces the number of detections by the second characteristic detector 42 to less than the predetermined number of detections. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0095] (4. Other) The above description of the embodiment and the modified example is merely an example of the image forming system according to the present invention, and the present invention is not limited to this. For example, in the above embodiment and modified examples, the first characteristic detector 23 and the second characteristic detectors 42, 53 detect the moisture content of the paper, which is characteristic information corresponding to the characteristics of the paper, but this is not limiting. The first characteristic detection unit 23 and the second characteristic detection units 42, 53 may detect the resistance value, stiffness, etc. of the paper as characteristic information corresponding to the characteristics of the paper. In particular, when detecting the resistance value or stiffness of the paper, the detection accuracy may be improved by stopping the paper or slowing down the conveying speed before measuring. However, stopping the paper or slowing down the conveying speed leads to a decrease in productivity. Furthermore, the lifespan of these detection sensors may be shortened depending on the usage conditions due to electrical or mechanical loads.

[0096] In the detection control process of the above embodiment and modified example, the third control unit 31 controls the second characteristic detection units 42, 53 based on the detection result of the first characteristic detection unit 23, but this is not limited to the above. The third control unit 31 may control the first characteristic detection unit 23 based on the detection result of the second characteristic detection units 42, 53.

[0097] In the above embodiment and modified example, the third control unit 31 functions as a control unit that controls the second characteristic detection units 42, 53 based on the detection result of the first characteristic detection unit 23, but is not limited to this. An external device that can communicate with the image forming system 100 may function as the control unit.

[0098] (5. Effects) As described above, the image forming system 100 of this embodiment includes the image forming unit 38 that forms an image on a recording medium (paper). The image forming system 100 of this embodiment includes a first characteristic detector 23 that is provided upstream of the image forming unit 38 in the conveying direction of the recording medium and detects characteristic information corresponding to the characteristics of the recording medium. The image forming system 100 of this embodiment includes second characteristic detectors 42 and 53 that are provided downstream of the image forming unit 38 in the conveying direction of the recording medium and detect characteristic information. In the image forming system 100 of this embodiment, based on the detection result of either the first characteristic detection unit 23 or the second characteristic detection unit 42, the other characteristic detection unit is controlled. Alternatively, based on the detection result of either the first characteristic detection unit 23 or the second characteristic detection unit 53, the other characteristic detection unit is controlled. This can reduce the number of detections by the first characteristic detection unit 23 or the second characteristic detection units 42, 53. This can prevent a decrease in the life span or productivity of the detection units that detect the characteristics of the paper.

[0099] In the image forming system 100 of this embodiment, the second characteristic detectors 42 and 53 are controlled based on the detection result of the first characteristic detector 23. This allows the number of detections by the second characteristic detectors 42 and 53 to be reduced.

[0100] In the image forming system 100 of this embodiment, the characteristic information is information corresponding to at least one of the moisture content, resistance, and stiffness of the recording medium (paper). This makes it possible to appropriately reduce the number of detections by the first characteristic detector 23 or the second characteristic detectors 42, 53 based on at least one of the moisture content, resistance, and stiffness of the paper.

[0101] The image forming system 100 of this embodiment includes a control unit (third control unit 31) that controls the second characteristic detection units 42 and 53 based on the detection result of the first characteristic detection unit . This allows the number of detections by the second characteristic detectors 42 and 53 to be reduced.

[0102] The control unit (third control unit 31) in the image forming system 100 of this embodiment calculates the shrinkage rate of the recording medium (paper) based on the detection results of the first characteristic detection unit 23 and the second characteristic detection unit . Alternatively, the control unit (third control unit 31) in the image forming system 100 of this embodiment calculates the shrinkage rate of the recording medium (paper) based on the detection results of the first characteristic detection unit 23 and the second characteristic detection unit 53. This makes it possible to properly calculate the shrinkage rate of the paper before and after the image forming process by the image forming unit .

[0103] The control unit (third control unit 31) in the image forming system 100 of this embodiment controls the image forming conditions of the image forming unit 38 based on the shrinkage rate of the recording medium (paper). This makes it possible to set appropriate image forming conditions based on the shrinkage rate of the paper before and after the image forming process by the image forming unit 38.

[0104] The control unit (third control unit 31) in image forming system 100 of this embodiment controls second characteristic detection units 42 and 53 not to perform detection in accordance with the detection result of first characteristic detection unit . This allows the number of detections by the second characteristic detectors 42 and 53 to be reduced.

[0105] The control unit (third control unit 31) in the image forming system 100 of this embodiment controls the second characteristic detection units 42, 53 not to perform detection when the detection result of the first characteristic detection unit 23 is equal to or lower than a predetermined threshold value. This makes it possible to reduce the number of detections by the second characteristic detectors 42 and 53 in cases where the paper is unlikely to shrink even after the image forming process and the fixing process are performed.

[0106] In the image forming system 100 of this embodiment, the characteristic information is information corresponding to the moisture content of the recording medium. The control unit (third control unit 31) controls the second characteristic detection units 42, 53 not to perform detection when information corresponding to the moisture content detected by the first characteristic detection unit 23 is equal to or lower than a predetermined threshold value. This makes it possible to reduce the number of detections by the second characteristic detectors 42 and 53 in cases where the paper is unlikely to shrink even after the image forming process and the fixing process are performed.

[0107] The control unit (third control unit 31) in the image forming system 100 of this embodiment changes the detection method used by the second characteristic detection unit 42 depending on the detection result of the first characteristic detection unit 23. This makes it possible to reduce the number of detections by the second characteristic detector 42 by changing the detection method.

[0108] In the image forming system 100 of this embodiment, the characteristic information is information corresponding to the moisture content of the recording medium. The control unit (third control unit 31) changes the detection method used by the second characteristic detection unit 42 in accordance with the information corresponding to the moisture amount detected by the first characteristic detection unit 23. This makes it possible to reduce the number of detections by the second characteristic detector 42 in cases where the paper is unlikely to shrink even after the image forming process and the fixing process are performed.

[0109] The control unit (third control unit 31) in the image forming system 100 of this embodiment changes the detection frequency by the second characteristic detection unit 42 as a change in the detection method. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0110] The control unit (third control unit 31) in the image forming system 100 of this embodiment changes the detection position on the recording medium (paper) detected by the second characteristic detection unit 42 as a change in the detection method. When the number of detections by the second characteristic detector 42 is reduced, the position detected by the second characteristic detector 42 changes.

[0111] The first characteristic detection unit 23 and the second characteristic detection unit 42 in the image forming system 100 of this embodiment are capable of detecting characteristic information on one recording medium multiple times. The control unit (third control unit 31) changes the number of times the second characteristic detection unit 42 detects one recording medium, as a change in the detection method. This makes it possible to reduce the number of detections performed by the second characteristic detector .

[0112] The control unit (third control unit 31) in the image forming system 100 of this embodiment reduces the number of detections by the second characteristic detection unit 42 to less than a predetermined number of detections when the variation in the detection results of multiple detections by the first characteristic detection unit 23 is below a predetermined value. This makes it possible to reduce the number of detections by the second characteristic detection unit 42 when it is not necessary to perform detection multiple times by the second characteristic detection unit 42. This is the case when the variation in the detection results multiple times by the first characteristic detection unit 23 is equal to or less than a predetermined value, and when it is estimated that the variation in the detection results by the second characteristic detection unit 42 is also small.

[0113] The control unit (third control unit 31) in the image forming system 100 of this embodiment reduces the number of detections by the second characteristic detection unit 42 to less than a predetermined number of detections when multiple detection results by the first characteristic detection unit 23 are all below a predetermined threshold value. This makes it possible to reduce the number of detections by the second characteristic detector 42 in cases where the paper is unlikely to shrink even after the image forming process and the fixing process are performed.

[0114] The above-described embodiment and modified examples are examples of the image forming system, control method, and control program according to the present invention, and are not limited to these. The detailed configurations and detailed operations of each part constituting each device of the image forming system can also be appropriately changed without departing from the spirit of the present invention.

[0115] For example, in the above embodiment and modified example, the light receiving unit 233 receives the light emitted from the first light emitting unit 231 and the second light emitting unit 232 and reflected by the paper P, but this is not limited to the above. The light receiving unit 233 may be configured to receive the light emitted from the first light emitting unit 231 and the second light emitting unit 232 and transmitted through the paper P.

[0116] For example, in the above embodiment, the present invention is applied to the image forming apparatus 30 using an electrophotographic printing method, but the present invention is not limited to this. The present invention can also be applied to an inkjet image forming apparatus in which the paper shrinks before and after printing, or to image forming apparatuses using other printing methods. [Explanation of symbols]

[0117] 100 Image forming system 10 Paper feeder 11 First Control Section 12 Conveyor section 13 Paper feed section 14 Bus 20 First detection device 21 Second Control Section 22 Conveyor section 23 First characteristic detection unit 231 First light emitting part 232 Second light emitting part 233 Light receiving part 234, 235 Lenses 24 Bus 30 Image forming device 31 Third control section (control section) 32 Storage section 33 Operation section 34 Display section 35 Interface 36 Scanner 37 Image Processing Section 38 Image forming section 381 Exposure Section 382 Photoconductor drum 383 Development Department 384 Transcript 385 Secondary transfer roller 39 Image fixing section 40 Conveyor 401 Reversal mechanism 41 Bus 42 Second characteristic detection unit 50 Second detection device 51 4th Control Section 52 Conveyor 53 Second characteristic detection unit 54 Bus 60 Paper ejection device 61 5th Control Section 62 Conveyor 63 1st Tray 64 2nd Tray 65 Bus P paper

Claims

1. an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; Equipped with an image forming system in which, based on a detection result of either one of the first characteristic detection unit and the second characteristic detection unit, the other characteristic detection unit is controlled;

2. 2. The image forming system according to claim 1, wherein the second characteristic detection unit is controlled based on a detection result of the first characteristic detection unit.

3. 2. The image forming system according to claim 1, wherein the characteristic information corresponds to at least one of a moisture content, a resistance, and a stiffness of the recording medium.

4. The image forming system according to claim 1 , further comprising a control unit that controls the second characteristic detection unit based on a detection result of the first characteristic detection unit.

5. The image forming system according to claim 4 , wherein the control unit calculates a shrinkage rate of the recording medium based on detection results of the first characteristic detection unit and the second characteristic detection unit.

6. The image forming system according to claim 4 , wherein the control unit controls the image forming conditions of the image forming unit based on a shrinkage rate of the recording medium.

7. 5. The image forming system according to claim 4, wherein the control section controls the second characteristic detection section not to perform detection in accordance with a detection result of the first characteristic detection section.

8. 8. The image forming system according to claim 7, wherein the control unit controls the second characteristic detection unit not to perform detection when the detection result of the first characteristic detection unit is equal to or less than a predetermined threshold value.

9. the characteristic information is information corresponding to a moisture content of the recording medium, 9. The image forming system according to claim 8, wherein the control unit controls the second characteristic detection unit not to perform detection when information corresponding to the moisture amount detected by the first characteristic detection unit is equal to or less than a predetermined threshold value.

10. The image forming system according to claim 4 , wherein the control unit changes a detection method used by the second characteristic detection unit depending on a detection result of the first characteristic detection unit.

11. the characteristic information is information corresponding to a moisture content of the recording medium, The image forming system according to claim 10 , wherein the control unit changes a detection method used by the second characteristic detection unit in accordance with information corresponding to the amount of moisture detected by the first characteristic detection unit.

12. The image forming system according to claim 10 , wherein the control unit changes the detection method by changing a detection frequency by the second characteristic detection unit.

13. The image forming system according to claim 12 , wherein the control unit changes the detection method by changing a detection position on the recording medium detected by the second characteristic detection unit.

14. the first characteristic detection unit and the second characteristic detection unit are capable of detecting the characteristic information on one recording medium a plurality of times; The image forming system according to claim 10 , wherein the control unit changes the number of times the second characteristic detection unit detects one recording medium, as the change in the detection method.

15. 15. The image forming system according to claim 14, wherein the control unit reduces the number of detections by the second characteristic detection unit to less than a predetermined number of detections when a variation in the results of multiple detections by the first characteristic detection unit is equal to or less than a predetermined value.

16. The image forming system according to claim 14 , wherein the control unit reduces the number of detections by the second characteristic detection unit to less than a predetermined number of detections when the multiple detection results by the first characteristic detection unit are all equal to or less than a predetermined threshold value.

17. an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; A control method for an image forming system comprising: A control method in which, based on a detection result of one of the first characteristic detection unit and the second characteristic detection unit, the other characteristic detection unit is controlled.

18. an image forming unit that forms an image on a recording medium; a first characteristic detection unit that is provided upstream of the image forming unit in a conveying direction of the recording medium and detects characteristic information corresponding to a characteristic of the recording medium; a second characteristic detection unit that is provided downstream of the image forming unit in a conveying direction of the recording medium and detects the characteristic information; A computer of an image forming system comprising: a control program that causes one of the first characteristic detection unit and the second characteristic detection unit to function as a control unit that controls the other characteristic detection unit based on a detection result of the other characteristic detection unit.

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