Image forming system, image forming apparatus, and program

Abstract

To provide an image formation system, an image formation device and a program which can provide a high-quality printed matter by suppressing degradation of the transfer property of a transfer unit due to the influence of implementing sheet heating before fixation.SOLUTION: An image formation system 100 comprises: an image formation device 30 having a transfer unit which transfers a toner image to a sheet P and a fixation unit 36 which fixes a toner image transferred by the transfer unit to the sheet; a sheet heating device 20 which heats the sheet on the upstream side in the sheet conveyance direction with respect to the fixation unit 36; a first detection unit which detects the in-device temperature of the image formation device 30; a second detection unit which detects the temperature of the sheet before heating; a control unit (control unit 31) which causes the sheet heating device 20 to execute sheet heating processing on the basis of the detection result by the second detection unit and a sheet passage condition of the sheet P; and a correction unit (control unit 31) which corrects at least one of the transfer current and the transfer voltage in the transfer unit on the basis of the detection result by the first detection unit when the sheet heating processing is executed.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an image forming system, an image forming apparatus, and a program.

Background Art

[0002] Conventionally, image forming apparatuses such as printers and copiers that employ an electrophotographic method have been widely used. In such an image forming apparatus, generally, a laser beam is irradiated onto a photoreceptor drum whose surface is uniformly charged by an optical device to write an electrostatic latent image, and after developing the electrostatic latent image with toner in a developing device, the developed toner image is transferred to a sheet via an intermediate transfer belt, and then the transferred toner image is fixed to the sheet, and image forming processing is performed through a series of processes. By the way, when such an image forming apparatus is used in a low-temperature and low-humidity environment or a high-temperature and high-humidity environment, the transferability deteriorates due to fluctuations in the resistance values of the transfer member and the sheet caused by environmental changes, or the fixability deteriorates due to fluctuations in the sheet temperature.

[0003] In this regard, for example, Patent Document 1 describes a recording apparatus provided with heating means for heating a sheet (medium) between a paper feeding unit (hopper) and a transfer unit (transfer apparatus) that transfers a toner image onto the medium. According to the recording apparatus, it is possible to suppress deterioration of transferability and fixability by heating the sheet to keep the sheet temperature constant even in a low-temperature and low-humidity environment.

Prior Art Documents

Patent Documents

[0004] [[ID=^28]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when a heating means is provided between the paper feeding unit and the transfer unit as in the invention described in Patent Document 1, considering the fixing property, the paper heated by the heating means passes through the transfer unit, and the transfer unit is overheated, resulting in a problem that the resistance value of the transfer unit fluctuates and the transfer property deteriorates. In addition, there is also a possibility that the temperature of the transfer unit rises due to the heat generated by the heating means itself, leading to a deterioration of the transfer property. Since the invention described in Patent Document 1 heats the paper to keep the transfer voltage constant, it cannot solve the above-described problems.

[0006] An object of the present invention is to provide an image forming system, an image forming apparatus, and a program that can suppress deterioration of the transfer property of a transfer unit due to the influence of paper heating before fixing and provide a high-quality printed matter.

Means for Solving the Problems

[0007] To solve the above problems, the image forming system according to the invention described in claim 1 includes: An image forming apparatus including a transfer unit that transfers a toner image onto a paper, and a fixing unit that fixes the toner image transferred by the transfer unit onto the paper; A paper heating device that heats the paper upstream of the fixing unit in the paper conveyance direction; A first detection unit that detects the temperature inside the apparatus of the image forming apparatus; A second detection unit that detects the temperature of the paper before heating; A control unit that causes the paper heating device to perform a paper heating process based on the detection result by the second detection unit and the paper passing condition; A correction unit that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the first detection unit when the paper heating process is performed; A fourth detection unit that detects the temperature of the paper after being heated by the paper heating device; and 、 Based on the difference between the detection result by the second detection unit and the detection result by the fourth detection unit, the correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit. is provided.

[0008] The invention described in claim 2 is the invention described in claim 1, wherein The first detection unit detects the temperature near the transfer unit.

[0009] The invention according to claim 3 is the invention according to claim 2, wherein a third detection unit for detecting the ambient temperature inside or outside the apparatus of the image forming apparatus is provided, the correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the difference between the detection result by the first detection unit and the detection result by the third detection unit.

[0010] The invention according to claim 4 is the invention according to claim 2 or 3, wherein the first detection unit detects the temperature near the transfer unit in a non-contact manner, and a plurality of the first detection units are provided at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper.

[0011] The invention according to claim 5 is the invention according to any one of claims 2 to 4, wherein a determination unit for determining whether the detection result by the first detection unit is equal to or greater than a predetermined value is provided, when the determination unit determines that the detection result by the first detection unit is equal to or greater than a predetermined value, the control unit reduces the heating amount by the paper heating device and decelerates the paper conveyance speed.

[0012] The invention according to claim 6 is the invention according to any one of claims 2 to 4, wherein a determination unit for determining whether the detection result by the first detection unit is equal to or greater than a predetermined value, and a cooling unit for cooling the vicinity of the transfer unit are provided, when the determination unit determines that the detection result by the first detection unit is equal to or greater than a predetermined value, the control unit cools the vicinity of the transfer unit by the cooling unit.

[0013] The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the paper passing condition includes at least one of the paper conveyance speed, the paper type of the paper, and the basis weight of the paper.

[0015] Claim 8 The invention described in claim Any one of 1 to 7 In the invention described in claim A plurality of the second detection unit and the fourth detection unit are provided at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper.

[0016] Claim 9 The invention described in claim 8 In the invention described in any one of claims 1 to The paper is continuous paper.

[0017] Claim 10 The image forming apparatus according to the invention described in claim An image forming apparatus that forms an image on a paper heated by a paper heating device, A transfer unit that transfers a toner image to the paper, A fixing unit that fixes the toner image transferred by the transfer unit to the paper, A detection unit that detects the temperature inside the apparatus, The temperature of the paper before heating , and the temperature of the paper after being heated by the paper heating device An acquisition unit that acquires A control unit that causes the paper heating device to perform a paper heating process based on the acquisition result by the acquisition unit and the paper passing condition of the paper, A correction unit that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the detection unit when the paper heating process is executed, Comprising 、 Based on the difference between the temperature of the paper before heating and the temperature of the paper after being heated by the paper heating device, the correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit. Yes.

[0018] Claim 11 The program according to the invention described in claim An image forming apparatus including a transfer unit that transfers a toner image to a paper and a fixing unit that fixes the toner image transferred by the transfer unit to the paper, A paper heating device that heats the paper upstream of the fixing unit in the paper conveyance direction, A first detection unit that detects the temperature inside the image forming apparatus, A second detection unit that detects the temperature of the paper before heating, A fourth detection unit that detects the temperature of the paper after being heated by the paper heating device; A computer of an image forming system including: A control unit that causes the paper heating device to perform a paper heating process based on the detection result by the second detection unit and the paper passing condition of the paper, A correction unit that corrects at least one of a transfer current or a transfer voltage in the transfer unit based on the detection result by the first detection unit when the paper heating process is performed, Function as 、 Based on the difference between the detection result by the second detection unit and the detection result by the fourth detection unit, the correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit. Yes.

Effect of the Invention

[0019] According to the present invention, it is possible to provide a high-quality printed matter by suppressing deterioration of the transferability of the transfer unit due to the influence of paper heating before fixing.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 7C

Figure 8

Best Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[0022] [Configuration of Image Forming System] FIG. 1 is a diagram showing an overall configuration example of an image forming system 100 according to an embodiment. The image forming system 100 is a system that forms an image on a sheet P, which is a continuous sheet such as roll paper, roll film, or continuous forms.

[0023] As shown in FIG. 1, the image forming system 100 is configured by connecting a paper feeding device 10, a paper heating device 20, an image forming device 30, and a winding device 40 in this order from the upstream side along the conveyance direction (paper conveyance direction) of the sheet P. In FIG. 1, the case where the paper feeding device 10, the paper heating device 20, and the winding device 40 are configured separately from the image forming device 30 is shown, but they may be integrally configured.

[0024] The paper feeding device 10 is a device that feeds the sheet P to the paper heating device 20. The paper feeding device 10 conveys the sheet P wound around the support shaft X to the paper heating device 20 at a constant speed by driving a motor (not shown). The operation of the motor of the paper feeding device 10 is controlled by a control unit 31 (FIG. 4) provided in the image forming device 30.

[0025] The paper heating device 20 heats the sheet P conveyed from the paper feeding device 10 and conveys it to the image forming device 30. FIG. 2 shows a configuration example of the paper heating device 20. In the example shown in FIG. 2, the paper conveyance direction is indicated by an arrow. The paper heating device 20 includes a paper conveyance unit 21, a first heating unit 22, a second heating unit 23, a first paper temperature detection unit 24 (second detection unit), a second paper temperature detection unit 25 (fourth detection unit), and the like.

[0026] The paper conveyance unit 21 has a paper passage 211 and the like, and conveys the paper P conveyed from the paper feeding device 10 to the paper heating device 20 to the image forming device 30 based on the control of the control unit 31.

[0027] The first heating unit 22 and the second heating unit 23 are, for example, rollers in which a heating source H such as a halogen heater is disposed inside a rotatable heat-conductive sleeve made of aluminum. The first heating unit 22 heats the back surface (one surface) of the paper P by contacting the back surface of the paper P passing through the paper passage 211. The second heating unit 23 heats the front surface of the paper P by contacting the front surface (the surface opposite to the surface heated by the first heating unit 22) of the paper P passing through the paper passage 211.

[0028] The first paper temperature detection unit 24 is disposed upstream of the first heating unit 22 in the paper conveyance direction, non-contact detects the temperature of the front surface of the paper P before heating in the paper heating device 20, and outputs the detection result to the control unit 31. FIG. 3 shows a top view schematically showing the first paper temperature detection unit 24. In the example shown in FIG. 3, the paper conveyance direction is indicated by an arrow. As shown in FIG. 3, the first paper temperature detection units 24 are arranged at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper P. In the present embodiment, one first paper temperature detection unit 24 is provided at each of both end portions and the central portion in the width direction of the paper P. Note that the number of the first paper temperature detection units 24 is not limited to this. It is sufficient that one or more are provided. The second paper temperature detection unit 25 is disposed downstream of the second heating unit 23 in the paper conveyance direction, non-contact detects the temperature of the front surface of the paper P after heating in the paper heating device 20, and outputs the detection result to the control unit 31. Note that the first paper temperature detection unit 24 and the second paper temperature detection unit 25 may be of a contact type, but in the contact type, a temperature difference may occur between the contacted portion and the non-contacted portion. Therefore, the non-contact type is preferable because the temperature can be detected more accurately. Similar to the first sheet temperature detection unit 24, the second sheet temperature detection units 25 are arranged at intervals in a direction orthogonal to the sheet conveyance direction and parallel to the surface of the sheet P. In the present embodiment, one second sheet temperature detection unit 25 is provided at each of both end portions and the central portion in the width direction of the sheet P. Note that the number of the second sheet temperature detection units 25 is not limited to this, and one or more may be provided.

[0029] The image forming apparatus 30 forms an image on the sheet P conveyed from the sheet heating apparatus 20 by an intermediate transfer method using an electrophotographic process technology. As shown in FIG. 4, the image forming apparatus 30 includes a control unit 31, a storage unit 32, an operation display unit 33, an image forming unit 34, a sheet conveyance unit 35, a fixing unit 36, a communication unit 37, and the like. Further, the image forming apparatus 30 includes an in-device temperature detection unit 38 (third detection unit, detection unit) that detects the ambient temperature (in-device temperature) inside the image forming apparatus 30. When a correction unit described later corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the first detection unit when performing a sheet heating process, the in-device temperature detection unit 38 may be used as the first detection unit. The in-device temperature detection unit 38 outputs the result of detecting the in-device temperature to the control unit 31.

[0030] The control unit 31 includes a CPU (Central Processing Unit) 31a, a ROM (Read Only Memory) 31b, a RAM (Random Access Memory) 31c, and the like. The CPU �1a reads a program corresponding to the processing content from the ROM 31b and expands it in the RAM 31c, and centrally controls the operations of each part of the image forming apparatus 30 and the operations of the paper feeding apparatus 10, the sheet heating apparatus 20, the winding apparatus 40, and the like in cooperation with the expanded program.

[0031] Further, the control unit 31 causes the sheet heating apparatus 20 to execute a sheet heating process described later based on the detection result by the second detection unit (first sheet temperature detection unit 24) and the sheet passing conditions. Here, the control unit 31 functions as a control unit. Further, when the paper heat treatment is executed, the control unit 31 corrects at least one of the transfer current or the transfer voltage in the transfer unit (secondary transfer roller 343, opposing roller 344) based on the detection results by the first detection units (the in-device temperature detection unit 38, the transfer unit temperature detection unit 346). Here, the control unit 31 functions as a correction unit. Further, the control unit 31 determines whether the detection result by the first detection unit (transfer unit temperature detection unit 346) described later is equal to or higher than a predetermined value. Here, the control unit 31 functions as a determination unit. Further, the control unit 31 acquires the temperature of the paper P before heating from the first paper temperature detection unit 24. Here, the control unit 31 functions as an acquisition unit.

[0032] The storage unit 32 is configured by, for example, a non-volatile semiconductor memory (so-called flash memory), a hard disk drive, or the like. The storage unit 32 stores the input job information, manuscript data, various setting information, image data, and the like. The job information includes the conveyance speed of the paper P as a paper passing condition, the paper type of the paper P, the basis weight, and the like. Further, the storage unit 32 stores the conditions for heating the paper and the amount of current flowing through the heating source H in the transfer current correction process described later. Further, the storage unit 32 stores the threshold value of the temperature near the transfer unit (the detection result by the transfer unit temperature detection unit 346 described later) used in the transfer current correction process described later, the threshold value in the difference between the in-device temperature (the detection result by the in-device temperature detection unit 38) and the temperature near the transfer unit (the detection result by the transfer unit temperature detection unit 346), the table of the set values of the transfer current, the first correction value table, and the second correction value table. Note that these data and the like may be stored in the RAM 31c of the control unit 31.

[0033] The operation display unit 33 is configured by, for example, a liquid crystal display (LCD: Liquid Crystal Display) with a touch panel, and functions as a display unit 331 and an operation unit 332. The display unit 331 displays various operation screens, the state of images, the operation status of each function, etc., in accordance with the display control signal input from the control unit 31. The operation unit 332 is provided with various operation keys such as numeric keys and a start key, accepts various input operations by the user, and outputs an operation signal to the control unit 31.

[0034] The image forming unit 34 forms toner images of each color of Y (yellow), M (magenta), C (cyan), and K (black) on the photoreceptor drums 341Y, 341M, 341C, and 341K based on image data input from an external device (such as a personal computer) via the communication unit 37, for example, and sequentially performs primary transfer to the intermediate transfer belt 342 to overlap the four-color toner images. Then, secondary transfer is performed to the paper P conveyed from the paper heating device 20 by the secondary transfer roller 343 and the opposing roller 344, thereby forming (printing) an image. Also, after secondary transfer, the transfer residual toner remaining on the intermediate transfer belt 342 is removed by the cleaning unit 347 on the downstream side.

[0035] The secondary transfer roller 343 and the opposing roller 344 are the transfer unit. Also, the secondary transfer roller 343 and the opposing roller 344 form a secondary transfer nip portion 345 when the secondary transfer roller 343 abuts on the opposing roller 344. The control unit 31 controls a power source (not shown) and applies a positive voltage with a polarity opposite to the charging polarity of the toner so that a predetermined current, which is the transfer current, flows through the secondary transfer nip portion 345 to the secondary transfer roller 343.

[0036] Also, the image forming unit 34 is provided with a transfer unit temperature detection unit 346 (first detection unit, detection unit) that is arranged near the transfer unit and detects the temperature near the transfer unit in a non-contact manner. The transfer unit temperature detection unit 346 outputs the result of detecting the temperature near the transfer unit to the control unit 31. Fig. 5 shows a bottom view schematically showing the transfer unit temperature detection unit. In the example shown in Fig. 5, the paper conveyance direction is indicated by an arrow. As shown in FIG. 5, the transfer unit temperature detection unit 346 is arranged in a plurality at intervals in a direction orthogonal to the paper conveyance direction of the secondary transfer roller 343 and parallel to the surface of the paper P. In the present embodiment, one transfer unit temperature detection unit 346 is provided at each of both end portions and the central portion in the width direction of the paper P of the secondary transfer roller 343. Note that the number of transfer unit temperature detection units 346 is not limited to this. It is sufficient that one or more are provided.

[0037] The paper conveyance unit 35 has a paper passage 352 and the like including a plurality of conveyance rollers. Based on the control of the control unit 31, the paper conveyance unit 35 conveys the paper P conveyed from the paper heating device 20 to the image forming device 30 to the image forming unit 34, and conveys the paper P on which the toner image has been formed in the image forming unit 34 to the fixing unit 36. Then, the paper P on which the toner image has been fixed in the fixing unit 36 is conveyed to the winding device 40.

[0038] The fixing unit 36 includes a fixing heater, a fixing roller, a fixing external heating unit, etc., and thermally fixes the toner image transferred to the paper.

[0039] The communication unit 37 is composed of a communication control card such as a LAN (Local Area Network) card, and performs transmission and reception of various data with an external device (for example, a personal computer) connected to a communication network such as a LAN or a WAN (Wide Area Network).

[0040] The winding device 40 is a device that winds the paper P conveyed from the image forming device 30. The winding device 40 winds the paper P conveyed from the image forming device 30 around the support shaft Y at a constant speed by driving a motor (not shown). The winding operation of the winding device 40 is controlled by the control unit 31 provided in the image forming device 30.

[0041] (Operation of the image forming system 100) Next, the operation of the image forming system 100 of the present embodiment will be described. FIG. 6 shows a flowchart of the transfer current correction process executed in the image forming system 100. The transfer current correction process is executed by a program stored in the control unit 31 at the timing when an instruction to start a job is received via the operation unit 332 or the communication unit 37. When the transfer current correction process starts, the heat source H of the paper heating device 20 is in the OFF state.

[0042] First, the control unit 31 acquires from the storage unit 32 information on the paper conveyance speed, the paper type of the paper P, and the basis weight, which are the paper passing conditions of the job for which the start instruction has been received (step S1). Note that the paper passing conditions may include at least any one of the information on the paper conveyance speed, the paper type of the paper P, and the basis weight of the paper P. Next, the control unit 31 controls the in-device temperature detection unit 38 to acquire the in-device temperature, and controls the first paper temperature detection unit 24 to acquire the temperature of the surface of the paper P (step S2). As the temperature of the surface of the paper P detected by the first paper temperature detection unit 24, an average value of the detection results by a plurality of first paper temperature detection units 24 may be acquired, or the detection result by one of the plurality of first paper temperature detection units 24 may be acquired. Next, the control unit 31 determines whether to heat the paper P by the paper heating device 20 based on the paper passing conditions acquired in step S1 and the in-device temperature and the temperature of the surface of the paper P acquired in step S2 (step S3). The conditions for heating the paper P in the paper passing conditions, the in-device temperature, and the temperature of the surface of the paper P are preset.

[0043] When heating the paper P (step S3; YES), the control unit 31 controls the paper heating device 20 to turn on the heat source H to heat the paper P and convey it to the image forming device 30 (step S4). Here, the amount of current flowing through the heat source H is preset in a table or the like based on the paper passing conditions, the in-device temperature, and the temperature of the surface of the paper P. Step S4 is a paper heating process. When not heating the paper P (step S3; NO), the control unit 31 does not heat the paper P with the heat source H remaining OFF, conveys it to the image forming device 30, and proceeds to step S5.

[0044] Next, the control unit 31 starts the job (step S5). Next, the control unit 31 controls the in-device temperature detection unit 38 to obtain the in-device temperature, and controls the transfer unit temperature detection unit 346 to obtain the temperature near the transfer unit (step S6). As the temperature near the transfer unit detected by the transfer unit temperature detection unit 346, an average value of detection results by a plurality of transfer unit temperature detection units 346 may be obtained, or a detection result by one of the plurality of transfer unit temperature detection units 346 may be obtained. Next, the control unit 31 determines whether or not the temperature near the transfer unit obtained in step S6 is equal to or lower than a threshold value (step S7). The threshold value is set in advance. When the temperature near the transfer unit is not equal to or lower than the threshold value (step S7; NO), the control unit 31 reduces the amount of heat applied to the sheet P by, for example, reducing the amount of current flowing through the heat source H of the sheet heating device 20. Further, in order to ensure high transferability even when the amount of heat applied is reduced, the sheet conveyance speed during the transfer process in the transfer unit is decelerated (step S8), and this process is shifted to step S6.

[0045] When the temperature near the transfer unit is equal to or lower than the threshold value (step S7; YES), the control unit 31 determines whether or not the difference between the in-device temperature and the temperature near the transfer unit obtained in step S6 is equal to or greater than a threshold value (step S9). The threshold value is set in advance. When the difference between the in-device temperature and the temperature near the transfer unit is equal to or greater than the threshold value (step S9; YES), the control unit 31 obtains the set value of the transfer current flowing through the secondary transfer nip unit 345 from the table of the set values of the transfer current stored in the storage unit 32 (step S10). A table of the set values of the transfer current is shown in FIG. 7A. In the present embodiment, the paper type of the sheet P is coated paper gloss, and the basis weight is 257 to 300 [gsm]. In this case, as shown in FIG. 7A, the set value of the transfer current is -180 [uA].

[0046] Next, based on the temperature inside the apparatus and the temperature near the transfer unit acquired in step S6, the control unit 31 obtains a correction value for the transfer current based on the difference between the temperature inside the apparatus and the temperature near the transfer unit from the first correction value table stored in the storage unit 32 (step S11). The correction value for the transfer current based on the difference between the temperature inside the apparatus and the temperature near the transfer unit is a correction value for the change in the resistance value of the transfer unit due to the temperature change of the transfer unit. The first correction value table is shown in FIG. 7B. In this embodiment, the difference between the temperature inside the apparatus and the temperature near the transfer unit is 10 [°C]. In this case, as shown in FIG. 7B, the correction value for the transfer current based on the difference between the temperature inside the apparatus and the temperature near the transfer unit is +10 [μA].

[0047] Next, the control unit 31 controls the first sheet temperature detection unit 24 to obtain the temperature of the surface of the sheet P before heating, and controls the second sheet temperature detection unit 25 to obtain the temperature of the surface of the sheet P after heating (step S12). As the temperature of the surface of the sheet P detected by the first sheet temperature detection unit 24, an average value of the detection results by a plurality of first sheet temperature detection units 24 may be obtained, or a detection result by one of the plurality of first sheet temperature detection units 24 may be obtained. Similarly, as the temperature of the surface of the sheet P detected by the second sheet temperature detection unit 25, an average value of the detection results by a plurality of second sheet temperature detection units 25 may be obtained, or a detection result by one of the plurality of second sheet temperature detection units 25 may be obtained. Next, the control unit 31 calculates the difference from the temperatures of the surface of the sheet P before and after heating acquired in step S12, and obtains a correction value for the transfer current based on the difference between the temperatures of the sheet before and after heating from the second correction value table stored in the storage unit 32 (step S13). The correction value for the transfer current based on the difference between the temperatures of the sheet before and after heating is a correction value for the change in the resistance value of the sheet P due to the temperature change of the sheet P. The second correction value table is shown in FIG. 7C. In this embodiment, the difference between the temperatures of the sheet before and after heating is 15 [°C]. In this case, as shown in FIG. 7C, the correction value for the transfer current based on the difference between the temperatures of the sheet before and after heating is +12 [μA].

[0048] Next, the control unit 31 corrects the transfer current value based on the set value of the transfer current acquired in step S10, the correction value of the transfer current due to the difference between the temperature inside the apparatus and the temperature near the transfer unit acquired in step S11, and the correction value of the transfer current due to the difference in the paper temperature before and after heating acquired in step S13, and controls the power supply to output the corrected transfer current value (step S14). Specifically, as described above in this embodiment, the set value of the transfer current is -180 [uA], the correction value of the transfer current due to the difference between the temperature inside the apparatus and the temperature near the transfer unit is +10 [uA], and the correction value of the transfer current due to the difference in the paper temperature before and after heating is +12 [uA]. In this case, the corrected transfer current value is the sum of these (-180 [uA] + 10 [uA] + 12 [uA]), which is -158 [uA].

[0049] Next, the control unit 31 determines whether the job has ended (step S15). If the job has ended (step S15; YES), the control unit 31 ends this process. Also, if the job has not ended (step S15; NO), the control unit 31 proceeds to step S6 in this process. Also, if the difference between the temperature inside the apparatus and the temperature near the transfer unit is not equal to or greater than the threshold value (step S9; NO), the control unit 31 proceeds to step S15 in this process.

[0050] In addition, in the above transfer current correction process, when the first paper temperature detection unit 24 is controlled to acquire the temperature of the surface of the paper P, if the difference between the detection results of the plurality of first paper temperature detection units 24 is equal to or greater than a preset predetermined value, the control unit 31 may stop the job and notify the user by displaying a warning on the display unit 331 or the like. This is the same when the transfer unit temperature detection unit 346 is controlled to acquire the temperature near the transfer unit and when the second paper temperature detection unit 25 is controlled to acquire the temperature of the surface of the paper P.

[0051] Also, in step S8 of the transfer current correction process, although the heating amount applied to the sheet P is reduced and the sheet conveyance speed during the transfer process in the transfer unit is decelerated, it is not limited to this. As a method of lowering the temperature near the transfer unit, the image forming apparatus 30 may include a cooling fan 348 (cooling unit) near the transfer unit and lower the temperature near the transfer unit by driving the cooling fan 348. FIG. 8 shows the installation position of the cooling fan 348 provided in the image forming apparatus 30. Also, the cooling amount by the cooling fan 348, which is the amount of current flowing through the cooling fan 348, etc., may be set based on the temperature near the transfer unit.

[0052] As described above, the image forming system 100 in the above embodiment includes a transfer unit (secondary transfer roller 343, opposing roller 344) that transfers a toner image to the sheet P, and a fixing unit 36 that fixes the toner image transferred by the transfer unit to the sheet P. An image forming apparatus 30, a sheet heating device 20 that heats the sheet upstream of the fixing unit 36 in the sheet conveyance direction, a first detection unit (apparatus internal temperature detection unit 38, transfer unit temperature detection unit 346) that detects the temperature inside the image forming apparatus 30, a second detection unit (first sheet temperature detection unit 24) that detects the temperature of the sheet P before heating, a control unit (control unit 31) that causes the sheet heating device 20 to perform a sheet heating process based on the detection result by the second detection unit and the sheet passing condition of the sheet P, and when the sheet heating process is executed, a correction unit (control unit 31) that corrects at least one of the transfer current or transfer voltage in the transfer unit based on the detection result by the first detection unit. Therefore, it is possible to suppress deterioration of the transferability of the transfer unit due to the influence of sheet heating before fixing and provide a high-quality printed matter.

[0053] Also, in the image forming system 100 in the above embodiment, the first detection unit detects the temperature near the transfer unit. Therefore, based on the temperature near the transfer unit, at least one of the transfer current or transfer voltage in the transfer unit can be corrected.

[0054] Further, the image forming system 100 in the above embodiment includes a third detection unit (in-device temperature detection unit 38) that detects the ambient temperature outside or inside the image forming apparatus 30, and the correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the difference between the detection result by the first detection unit and the detection result by the third detection unit. Therefore, even if there is a change in the resistance value of the transfer unit due to a temperature change in the transfer unit, it is possible to suppress the deterioration of the transfer performance of the transfer unit and provide a high-quality printed matter.

[0055] Also, in the image forming system 100 in the above embodiment, the first detection unit detects the temperature near the transfer unit in a non-contact manner, and a plurality of the first detection units are provided at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper P. Therefore, the temperature near the transfer unit can be detected more accurately.

[0056] Further, the image forming system 100 in the above embodiment includes a determination unit (control unit 31) that determines whether the detection result by the first detection unit is equal to or greater than a predetermined value. When the determination unit determines that the detection result by the first detection unit is equal to or greater than the predetermined value, the control unit 31 reduces the heating amount by the paper heating device 20 and decelerates the paper conveyance speed. Therefore, when the temperature near the transfer unit is equal to or greater than the predetermined value, the temperature of the transfer unit can be lowered by reducing the heating amount to the paper, and maintained at an appropriate temperature. Also, even if the temperature of the transfer unit is lowered, good transfer performance can be ensured.

[0057] Further, the image forming system 100 in the above embodiment includes a determination unit (control unit 31) that determines whether the detection result by the first detection unit is equal to or greater than a predetermined value, and a cooling unit (cooling fan 348) that cools the vicinity of the transfer unit. When the determination unit determines that the detection result by the first detection unit is equal to or greater than the predetermined value, the control unit 31 cools the vicinity of the transfer unit by the cooling unit. Therefore, when the temperature near the transfer unit is equal to or greater than the predetermined value, the temperature of the transfer unit can be lowered by the cooling fan 348 and maintained at an appropriate temperature.

[0058] In the image forming system 100 according to the above embodiment, the paper passing condition includes at least any one of the conveyance speed of the paper P, the paper type of the paper P, and the basis weight of the paper P. Therefore, it is possible to execute a more appropriate paper heat treatment based on the conveyance speed of the paper P, the paper type of the paper P, and the basis weight of the paper P.

[0059] The image forming system 100 according to the above embodiment further includes a fourth detection unit (second paper temperature detection unit 25) that detects the temperature of the paper after being heated by the paper heating device 20. The correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the difference between the detection result by the second detection unit and the detection result by the fourth detection unit. Therefore, even if there is a change in the resistance value of the paper P due to a change in the temperature of the paper P, it is possible to suppress the deterioration of the transferability of the transfer unit and provide a high-quality printed matter.

[0060] In the image forming system 100 according to the above embodiment, a plurality of second detection units and fourth detection units are provided at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper P. Therefore, it is possible to detect the temperature non-uniformity in the width direction of the paper.

[0061] In the image forming system 100 according to the above embodiment, the paper P is continuous paper. Therefore, even in continuous paper where the optimum value of the transfer current is likely to shift, it is possible to suppress the deterioration of the transferability of the transfer unit due to the influence of paper heating before fixing and provide a high-quality printed matter.

[0062] Further, the image forming apparatus 30 in the above embodiment is an image forming apparatus 30 that forms an image on a sheet P heated by the sheet heating apparatus 20, and includes a transfer unit (secondary transfer roller 343, opposing roller 344) that transfers a toner image to the sheet P, a fixing unit 36 that fixes the toner image transferred by the transfer unit to the sheet, a detection unit (in-device temperature detection unit 38, transfer unit temperature detection unit 346) that detects the temperature inside the apparatus, an acquisition unit (control unit 31) that acquires the temperature of the sheet P before heating, a control unit (control unit 31) that causes the sheet heating apparatus 20 to perform a sheet heating process based on the acquisition result by the acquisition unit and the sheet passing condition of the sheet P, and a correction unit (control unit 31) that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the detection unit when the sheet heating process is performed. Therefore, it is possible to suppress deterioration of the transferability of the transfer unit due to the influence of performing sheet heating before fixing and provide a high-quality printed matter.

[0063] Further, the present invention is not limited to the contents of the above embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, in the above embodiment, the second sheet temperature detection unit 25 is configured to detect the temperature of the surface (one surface) of the sheet, but may further include a detection unit that detects the temperature of the back surface of the sheet, and based on the detection unit, a transfer current correction process may be performed.

[0064] Further, although the sheet heating apparatus 20 in the above embodiment has a configuration as shown in FIG. 2, it is not limited thereto. A sheet heating apparatus that heats the sheet P by another method may also be used. Specifically, there are a non-contact indirect heating method in which the sheet is passed through a high-temperature atmosphere and heated, a non-contact direct heating method in which the sheet is heated by a heater, a contact heating method in which the sheet is passed between a pair of high-temperature rollers and heated, a contact heating method in which the sheet is passed between a pair of high-temperature belts and heated, and the like.

[0065] In addition, in the above embodiment, although the temperature of the surface of the paper P after heating is detected by the second paper temperature detection unit 25, the present invention is not limited to this. As the temperature of the surface of the paper P after heating, the temperature of the surface of the paper P between the paper heating device 20 and the image forming device 30, or the temperature of the surface of the paper P immediately before secondary transfer in the image forming device 30 may be detected. As the temperature of the surface of the paper P after heating, since the temperature at the position immediately before secondary transfer is closer to the true value, by detecting the temperature at the position immediately before secondary transfer, the transfer current value can be corrected more accurately, and the image quality can be ensured.

[0066] In addition, in the above embodiment, an outside device temperature detection unit for detecting the ambient temperature outside the image forming device 30 may be installed on the back surface or the like of the image forming device 30, and the temperature inside the device used in the transfer current correction process may be substituted with the outside device temperature or the average value of the outside device temperature and the temperature inside the device.

[0067] In addition, in step S3 of the transfer current correction process of the above embodiment, the control unit 31 determines whether to heat the paper P by the paper heating device 20 based on the paper passing condition and the temperature inside the device and the temperature of the surface of the paper P, but the present invention is not limited to this. It may be determined whether to heat the paper P by the paper heating device 20 based only on the paper passing condition and the temperature of the surface of the paper P. That is, the control unit 31 causes the paper heating device 20 to execute the paper heating process based on the detection result by the second detection unit and the paper passing condition of the paper.

[0068] In addition, in step S4 of the transfer current correction process of the above embodiment, the amount of current flowing through the heating source H is preset based on the paper passing condition, the temperature inside the device, and the temperature of the surface of the paper P, but the present invention is not limited to this. The amount of current flowing through the heating source H may be a fixed value, and the heating amount may be adjusted by switching the ON / OFF of the heating source H based on the paper passing condition, the temperature inside the device, and the temperature of the surface of the paper P.

[0069] Also, in the above embodiment, the transfer unit temperature detection unit 346 may be disposed at a position other than the position shown in FIG. 1. For example, the transfer unit temperature detection unit 346 may detect the vicinity of the cleaning unit 347 on the intermediate transfer belt 342 immediately after secondary transfer. In this case, in step S9 of the transfer current correction process, it is preferable to use a threshold value corresponding to the position where the transfer unit temperature detection unit 346 is disposed when determining whether the difference between the temperature inside the apparatus and the temperature near the transfer unit is equal to or greater than the threshold value. Thereby, the transfer current value can be corrected more accurately, and the image quality can be ensured.

[0070] Also, in step S12 of the transfer current correction process of the above embodiment, although the temperature of the surface of the sheet P before heating is obtained by controlling the first sheet temperature detection unit 24, the present invention is not limited to this. The temperature of the surface of the sheet P before heating may be substituted with the temperature inside the apparatus.

[0071] Also, in step S14 of the transfer current correction process of the above embodiment, although the transfer current value is corrected based on the set value of the transfer current, the correction value of the transfer current due to the difference between the temperature inside the apparatus and the temperature near the transfer unit, and the correction value of the transfer current due to the difference in the sheet temperature before and after heating, the present invention is not limited to this. The transfer current value may be corrected based only on the set value of the transfer current and the correction value of the transfer current due to the difference between the temperature inside the apparatus and the temperature near the transfer unit.

[0072] Also, in step S14 of the transfer current correction process of the above embodiment, although the transfer current value is corrected, the present invention is not limited to this. In step S14, the voltage (transfer voltage) applied to the transfer unit may be corrected, and the corrected transfer voltage may be applied to the transfer unit.

[0073] Also, in the above embodiment, although the sheet P is a continuous sheet, the present invention is not limited to this. The sheet P may be a long sheet or a single-sheet paper. However, since there is no gap between continuous sheets and the heated sheet P always contacts the transfer unit and heat exchange occurs while the sheet P is being heated by the sheet heating device 20, the optimum value of the transfer current is more likely to deviate. Therefore, when the sheet P is a continuous sheet, the effects of the present invention are more exhibited.

[0074] Also, in the above embodiment, the sheet heating device 20 is arranged between the sheet feeding device 10 and the image forming device 30, but it is not limited to this. The sheet heating device 20 may be arranged between the transfer unit and the fixing unit 36 in the image forming device 30. Even in this case, since the temperature of the transfer unit rises due to the heat generated by the sheet heating device 20, the present invention is effective.

[0075] In addition, regarding the detailed configuration and detailed operation of the image forming system 100, it can be appropriately changed within a range not departing from the gist of the present invention.

Explanation of Reference Numerals

[0076] 10 Sheet feeding device 20 Sheet heating device 21 Sheet conveyance unit 211 Sheet passing path 22 First heating unit 23 Second heating unit 24 First sheet temperature detection unit (second detection unit) 25 Second sheet temperature detection unit (fourth detection unit) 30 Image forming device 31 Control unit (control unit, correction unit, determination unit, acquisition unit) 32 Storage unit 33 Operation display unit 331 Display unit 332 Operation unit 34 Image forming unit 341 Photoconductor drum 342 Intermediate transfer belt 343 Secondary transfer roller (transfer unit) 344 Opposing roller (transfer unit) 345 Secondary transfer nip portion 346 Transfer unit temperature detection unit (first detection unit, detection unit) 347 Cleaning unit 348 Cooling fan (cooling unit) 35 Sheet conveyance unit 36 Fixing unit 37 Communication unit 38 Device internal temperature detection unit (first detection unit, third detection unit, detection unit) 40 Take-up device 100 Image forming system H Heat source P Paper

Claims

1. An image forming apparatus including a transfer unit that transfers a toner image onto a sheet, and a fixing unit that fixes the toner image transferred by the transfer unit onto the sheet; A sheet heating device that heats the sheet upstream of the fixing unit in the sheet conveyance direction; A first detection unit that detects the temperature inside the apparatus of the image forming apparatus; A second detection unit that detects the temperature of the sheet before heating; A control unit that causes the sheet heating device to perform a sheet heating process based on the detection result by the second detection unit and the sheet passing conditions; A correction unit that corrects at least one of a transfer current or a transfer voltage in the transfer unit based on the detection result by the first detection unit when the sheet heating process is performed; A fourth detection unit that detects the temperature of the sheet after being heated by the sheet heating device; Comprising: The correction unit corrects at least one of a transfer current or a transfer voltage in the transfer unit based on the difference between the detection result by the second detection unit and the detection result by the fourth detection unit. An image forming system.

2. The image forming system according to claim 1, wherein the first detection unit detects the temperature near the transfer unit.

3. Comprising a third detection unit that detects the ambient temperature outside or inside the apparatus of the image forming apparatus, The correction unit corrects at least one of a transfer current or a transfer voltage in the transfer unit based on the difference between the detection result by the first detection unit and the detection result by the third detection unit. The image forming system according to claim 2.

4. The first detection unit detects the temperature near the transfer unit in a non-contact manner, and a plurality of the first detection units are provided at intervals in a direction orthogonal to the sheet conveyance direction and parallel to the surface of the sheet. The image forming system according to claim 2 or 3.

5. Comprising a determination unit that determines whether the detection result by the first detection unit is equal to or greater than a predetermined value, When the determination unit determines that the detection result by the first detection unit is equal to or greater than a predetermined value, the control unit reduces the heating amount by the sheet heating device and decelerates the sheet conveyance speed. The image forming system according to any one of claims 2 to 4.

6. A determination unit that determines whether the detection result by the first detection unit is equal to or greater than a predetermined value, and A cooling unit that cools the vicinity of the transfer unit. When it is determined by the determination unit that the detection result by the first detection unit is equal to or greater than a predetermined value, the control unit cools the vicinity of the transfer unit by the cooling unit. The image forming system according to any one of claims 2 to 4.

7. The paper feeding condition includes at least any one of the conveyance speed of the paper, the paper type of the paper, and the basis weight of the paper. The image forming system according to any one of claims 1 to 6.

8. A plurality of the second detection unit and the fourth detection unit are provided at intervals in a direction orthogonal to the paper conveyance direction and parallel to the surface of the paper. The image forming system according to any one of claims 1 to 7.

9. The paper is continuous paper. The image forming system according to any one of claims 1 to 8.

10. An image forming apparatus that forms an image on a paper heated by a paper heating device, A transfer unit that transfers a toner image to the paper, A fixing unit that fixes the toner image transferred by the transfer unit to the paper, A detection unit that detects the temperature inside the apparatus, An acquisition unit that acquires the temperature of the paper before heating and the temperature of the paper after being heated by the paper heating device, A control unit that causes the paper heating device to perform a paper heating process based on the acquisition result by the acquisition unit and the paper feeding condition of the paper, A correction unit that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the detection unit when the paper heating process is performed, Comprising, The correction unit corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the difference between the temperature of the paper before heating and the temperature of the paper after being heated by the paper heating device. The image forming apparatus.

11. An image forming apparatus including a transfer unit that transfers a toner image to a paper and a fixing unit that fixes the toner image transferred by the transfer unit to the paper, A paper heating device that heats the paper upstream of the fixing unit in the paper conveyance direction, A first detection unit that detects the temperature inside the image forming apparatus, A second detection unit that detects the temperature of the paper before heating, A fourth detection unit that detects the temperature of the paper after being heated by the paper heating device, The computer of the image forming system including, A control unit that causes the paper heating device to perform a paper heating process based on the detection result by the second detection unit and the paper feeding condition of the paper, When the paper heat treatment is executed, a correction unit that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the detection result by the first detection unit, functioning as, The correction unit is a program that corrects at least one of the transfer current or the transfer voltage in the transfer unit based on the difference between the detection result by the second detection unit and the detection result by the fourth detection unit.

Images