Inkjet recording device

Abstract

To accurately detect the temperature in a nip section.SOLUTION: An inkjet recording device includes: a first belt that heats a sheet; heating means that heats the first belt in a non-contact manner; and a second belt that contacts the outer peripheral surface of the first belt to form a nip section together with the first belt and fixes an ink image on a sheet to the sheet together with the first belt. The inkjet recording device also includes: a pressing member that contacts the inner peripheral surface of the second belt in the nip section to press the first belt through the second belt, the pressure member having an opening formed in a heating area where the heating means performs heating; and a temperature detection member which is arranged in the opening and detects the temperature of the inner peripheral surface of the second belt.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a fixing device that fixes an image formed with ink onto a sheet, and an inkjet recording apparatus. [Background technology]

[0002] Conventionally, there is known an inkjet recording device that ejects ink toward a sheet to form an image on the sheet. In the inkjet recording device, a heating device is used to apply heat and pressure to the sheet on which an image is formed with ink, thereby causing the ink to penetrate the sheet and improve the fixability of the ink. As an example of such a heating device, a thermal fixing method is known that includes a fixing roller heated by a heating member having a heater, and a pressure roller that is in pressure contact with the fixing roller to form a fixing nip portion, and applies pressure and heat while nipping and conveying the sheet in the fixing nip portion.

[0003] Conventionally, in the case of electrophotographic image forming apparatuses, the heater temperature is controlled based on the detection result of a thermistor that detects the temperature of the fixing roller. Also, based on the detection result of the thermistor that detects the heater temperature, when the heater temperature reaches or exceeds a predetermined temperature, the power supply to the heater is stopped (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-53310 A Summary of the Invention [Problem to be solved by the invention]

[0005] In inkjet recording devices, a fixing device is proposed that fixes an ink image by applying heat and pressure after the image is formed on a sheet. Inkjet recording devices handle ink, so compared to electrophotographic fixing, a pair of belts nip the sheet with low-temperature heat for a long time to dry it.

[0006] The fixing device has a heating means for heating the pair of belts, and can apply heat to the sheet. For this heating means, a heater that does not come into contact with the belts is used because of its good thermal response, and the belts are heated by the radiant heat of the heater. A pressing member is provided in the nip portion formed by the pair of belts, which allows a long nip to be formed.

[0007] In this case, it is necessary to place a temperature detection means in the heating area of ​​the heater in case the heater goes out of control. However, if the temperature detection means is placed between the heater and the belt to measure the heating area of ​​the heater, the temperature detection means will be directly heated. Therefore, the heat resistance of the temperature detection means must be high, and it is difficult to place the temperature detection means between the heater and the belt.

[0008] An object of the inkjet recording apparatus according to the present invention is to detect the temperature in the nip portion with high accuracy. [Means for solving the problem]

[0009] In consideration of the above problems, the inkjet recording device of the present invention is characterized by having a first belt that heats a sheet, a heating means that is arranged inside the first belt and heats the first belt without contact, a second belt that forms a nip portion with the first belt by abutting against an outer peripheral surface of the first belt and fixes an ink image on the sheet to the sheet together with the first belt, a pressing member that abuts against an inner peripheral surface of the second belt at the nip portion and presses the first belt via the second belt, a heating means that heats the inner peripheral surface of the first belt without contact at the nip portion, and a temperature detection member that is arranged in the opening and detects the temperature of the inner peripheral surface of the second belt in a heating area heated by the heating means. Effect of the Invention

[0010] According to the present invention, since the temperature of the belt can be detected with good responsiveness, the increase in temperature of the belt can be stopped quickly even when an abnormality occurs, such as when the heater goes out of control. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing the overall configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a schematic cross-sectional view showing a fixing device according to an embodiment of the present invention; [Diagram 3] 3 is a schematic cross-sectional view showing a temperature detecting member and a second belt according to the embodiment. FIG. [Figure 4] 4A and 4B are diagrams illustrating the arrangement of temperature detection members according to the embodiment; [Diagram 5] FIG. [Figure 6] 2 is a flowchart of the present embodiment. [Figure 7] FIG. 11 is a schematic cross-sectional view showing a temperature detecting member and a second belt according to a second embodiment. [Figure 8] FIG. 13 is a block diagram of a third embodiment. [Figure 9] 13 is a flowchart of a third embodiment. [Figure 10] 10 is a flowchart of an abnormal temperature detection circuit according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Image forming device> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram showing an inkjet recording apparatus of this embodiment. The inkjet recording apparatus 1 is a so-called sheet-fed type inkjet recording apparatus that forms an ink image on a sheet using two liquids, namely, a reaction liquid and an ink. The sheet may be any recording material that can accept ink, such as paper such as plain paper or cardboard, plastic film such as an overhead projector sheet, a sheet of a special shape such as an envelope or index paper, or cloth.

[0013] 1, the inkjet recording apparatus 1 of this embodiment includes a paper feed module 1000, a print module 2000, a drying module 3000, a fixing module 4000, a cooling module 5000, an inverting module 6000, and a stacking module 7000. The sheet S supplied from the paper feed module 1000 undergoes various processes while being transported along a transport path in each module, and is finally discharged to the stacking module 7000.

[0014] Each of the modules from the paper feed module 1000 to the stacking module 7000 may have a separate housing, and these housings may be connected to configure the inkjet recording apparatus 1. Alternatively, the paper feed module 1000, the print module 2000, the drying module 3000, the fixing module 4000, the cooling module 5000, the reversing module 6000, and the stacking module 7000 may be arranged in a single housing.

[0015] The paper feed module 1000 has storage chambers 1500a, 1500b, and 1500c for storing sheets S, and the storage chambers 1500a to 1500c are provided so as to be able to be pulled out to the front side of the apparatus in order to store the sheets S. The sheets S are fed one by one in each of the storage chambers 1500a to 1500c by a separation belt and a transport roller, and are transported to the print module 2000. The number of storage chambers 1500a to 1500c is not limited to three, and one, two, or four or more may be provided.

[0016] The print module 2000 as an image forming section has a pre-imaging registration correction section (not shown), a print belt unit 2010, and a recording section 2020. The sheet S conveyed from the paper feed module 1000 has its inclination and position corrected by the pre-imaging registration correction section and is conveyed to the print belt unit 2010. The recording section 2020 is disposed at a position facing the print belt unit 2010 with respect to the conveying path. The recording section 2020 forms an image by discharging ink onto the conveyed sheet S from above using a recording head. A plurality of recording heads that discharge ink are arranged along the conveying direction. In this embodiment, in addition to the four colors of Y (yellow), M (magenta), C (cyan), and Bk (black), a total of five line-type recording heads corresponding to the reaction liquid are provided. The sheet S is attracted and conveyed by the print belt unit 2010, so that a clearance between the sheet S and the recording head is ensured.

[0017] The number of ink colors and recording heads is not limited to the above five. The inkjet method can employ a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, or the like. Each color of ink is supplied to the recording head from an ink tank (not shown) via an ink tube. The ink contains a resin component of "0.1% by mass to 20.0% by mass" based on the total mass of the ink, water, a water-soluble organic solvent, a coloring material, wax, additives, and the like.

[0018] When the sheet S on which an image is formed by the recording unit 2020 is transported by the print belt unit 2010, an in-line scanner (not shown) detects the misalignment and color density of the image formed on the sheet S. Based on the misalignment and color density of the image, the image to be formed on the sheet S, its density, etc. are corrected.

[0019] The drying module 3000 includes a decoupling section 3200, a drying belt unit 3300, and a hot air blowing section 3400. The drying module 3000 reduces the liquid content of the ink and reaction liquid applied to the sheet S in order to improve the fixation of the ink to the sheet S by the subsequent fixing module 4000. The sheet S on which an image is formed is transported to a decoupling section 3200 arranged in the drying module 3000. In the decoupling section 3200, frictional force is generated between the sheet S and the belt by the wind pressure of the wind blown from above, and the sheet S is transported by the belt. In this way, the sheet S placed on the belt is transported by frictional force, thereby preventing the sheet S from shifting when the sheet S is transported between the print belt unit 2010 and the decoupling section 3200. The sheet S transported from the decoupling section 3200 is adsorbed and transported by the drying belt unit 3300, and the ink and reaction liquid applied to the sheet S are dried by hot air blowing from the hot air blowing section 3400 arranged above the belt.

[0020] In this way, the ink and reaction liquid applied to the sheet S are heated by the drying module 3000 to promote evaporation of the moisture, thereby preventing so-called cockling, in which ink splatters on the sheet S and creates a border-like line around the periphery. The drying module 3000 may be any device capable of heating and drying, but a hot air dryer or heater is preferable. As the heater, for example, an electric heating wire or an infrared heater is preferable from the viewpoint of safety and energy efficiency.

[0021] The fixing module 4000 has a fixing belt unit 4100. The fixing belt unit 4100 fixes the ink image onto the sheet S by passing the sheet S conveyed from the drying module 3000 between a heated upper belt unit and a lower belt unit. The fixing belt unit 4100 will be described in detail later.

[0022] The cooling module 5000 has a plurality of cooling sections 5100, which cool the high-temperature sheet S transported from the fixing module 4000. The cooling section 5100, for example, takes in outside air with a fan into a cooling box to increase the pressure inside the cooling box, and cools the sheet S by blowing air from the cooling box through a nozzle due to the pressure against the sheet S. The cooling sections 5100 are disposed on both sides of the transport path of the sheet S, and cool both sides of the sheet S.

[0023] The cooling module 5000 is provided with a transport path switching unit 5002. The transport path switching unit 5002 switches the transport path of the sheet S depending on whether the sheet S is transported to the reversing module 6000 or to a double-sided transport path for double-sided printing in which images are formed on both sides of the sheet S.

[0024] The inversion module 6000 has an inversion section 6400. The inversion section 6400 inverts the sheet S being conveyed, and changes the orientation of the sheet S when it is discharged to the stacking module 7000. The stacking module 7000 has a top tray 7200 and a stacking section 7500, and stacks the sheet S conveyed from the inversion module 6000.

[0025] During double-sided printing, the sheet S is transported to a transport path below the cooling module 5000 by the transport path switching unit 5002. Thereafter, the sheet S passes through a double-sided transport path of the fixing module 4000, the drying module 3000, the print module 2000, and the paper feed module 1000, and is returned to the print module 2000. The double-sided transport section of the fixing module 4000 is provided with an inversion unit 4200 that inverts the sheet S. After the sheet S is returned to the print module 2000, an image is formed with ink on the other side on which the image is not formed. Thereafter, the sheet S passes through the drying module 3000, the fixing module 4000, the cooling module 5000, and the inversion module 6000, and is discharged to the stacking module 7000.

[0026] Next, an outline of the fixing module 4000 of this embodiment will be described with reference to Fig. 2. As shown in Fig. 2, the fixing module 4000 includes an upper belt unit 10 and a lower belt unit 20. The sheet S is sandwiched and conveyed between the upper belt unit 10 and the lower belt unit 20, and an ink image formed with ink is fixed to the sheet S by applying pressure and heat thereto.

[0027] FIG. 2 is a diagram showing the overall configuration of the fixing system in the image forming apparatus of the inkjet recording type according to the first embodiment, including an upper fixing belt system 10 and a lower fixing belt system 20. As shown in FIG.

[0028] In the inkjet recording method, after drying the sheet on which ink has been applied and evaporating the moisture, heat and pressure are applied to fix the image. The upper fixing belt system 10 and the lower fixing belt system 20 are fixing systems that allow the applied ink image to penetrate and be fixed in the sheet S by passing the dried sheet S through the nip between the heated first belt 11 and the second belt 21. The long nip between the upper and lower belts makes it easier for the ink to penetrate into the sheet, and makes it resistant to abrasion. Furthermore, by making the nip distance between the upper and lower belts long, high productivity is possible. The first belt 11 and the second belt 21 are rotated by driving rollers 104 and 204 by driving motors (not shown), respectively, to rotate the belts, and the sheet S is conveyed in the direction of the arrow. In the image forming apparatus of this embodiment, ink is applied to the upper surface (first belt 11 side) of the sheet S, and the first belt 11 side has on-demand heaters 110, 120, and 130 to dissolve the solvent component contained in the ink. The ink jet head further includes lower belt heaters 410 and 420 for auxiliary heating of the sheet S on which ink has been applied.

[0029] The on-demand heaters 110, 120, and 130 are provided inside the first belt. Furthermore, they are provided in a non-contact manner with respect to the first belt. By providing them in a non-contact manner, there is no obstacle to the belt to be heated, and heating can be performed with good thermal responsiveness.

[0030] As shown in Fig. 2, multiple on-demand heaters are provided along the sheet transport direction. In this embodiment, three on-demand heaters are provided, but the present invention is not limited to this and may be configured so long as multiple heaters are provided. In the case of a configuration having multiple on-demand heaters, the nip portion becomes larger in the sheet transport direction.

[0031] The upper fixing belt system 10 is composed of the first belt 11, the driving roller 104, the on-demand heaters 110, 120, 130, the temperature detection members 210, 220, 230, the temperature adjustment temperature sensor 310, and the rotation detection sensor 100. The on-demand heaters 110, 120, 130 are covered with reflectors 111, 121, 131, and heat the belt 11 directly below the on-demand heaters 110, 120, 130 without contact. The reflectors 111, 121, 131 focus the infrared light emitted from the heaters onto the belt 11. The temperature adjustment temperature sensor 310 detects the temperature of the belt 11. The rotation detection sensor 100 is disposed on the belt driven roller and is a sensor that detects whether the belt 11 is rotating. When the rotation of the belt 11 stops, the rotation detection sensor 100 detects it and the power supply to the on-demand heaters 110, 120, 130 is cut off. The pressing member 300 is a member that supports the long nip portion between the first belt 11 and the second belt 21 with its surface from the underside of the second belt 21. The thermoswitches 210, 220, and 230 as temperature detection members monitor the temperature abnormality of the second belt 21 through openings provided in the pressing member 300 at positions within the infrared irradiation range directly below the on-demand heaters 110, 120, and 130. When the temperature exceeds a predetermined threshold, the power supply to the on-demand heaters 110, 120, and 130 is cut off. The installation positions of the thermoswitches 210, 220, and 230 will be described in detail in FIG. 2 and FIG. 3. Also, the method of cutting off each on-demand heater when an abnormality is detected will be described in detail in FIG. 4.

[0032] The lower fixing belt system 20 is composed of the second belt 21, the driving roller 204, the lower belt heaters 410, 420, the thermoswitches 510, 520, the temperature adjustment temperature sensor 610, and the rotation detection sensor 200. The second belt 21 forms a nip portion by contacting the outer peripheral surface of the first belt 11. The lower belt heaters 410, 420 are configured as heating rollers having a heating element in a hollow roller, and heat the belt through the roller. The thermoswitches 510, 520 detect abnormal heating of the lower belt heaters 410, 420 and cut off the power supply to the lower belt heaters. The temperature adjustment temperature sensor 610 detects the temperature of the belt 21. The rotation detection sensor 200 is disposed on the driven roller and detects whether the belt 21 is rotating. When the rotation of the belt 21 stops, the rotation detection sensor 200 detects it and cuts off the power supply to the heaters 410, 420. The method for shutting off each heater when an abnormality is detected is explained in detail in Figure 4.

[0033] 3 is an example of a side view of the heating parts of the three on-demand heaters in the first embodiment, and will be described using the on-demand heater 110 as a representative example. The heating parts of the on-demand heaters 120 and 130 and the thermoswitches 220 and 230 have the same positional relationship.

[0034] The on-demand heaters 110, 120, 130 heat the first belt 11 within the range of the heating region 241, and the heat is also transmitted to the second belt 21 in the nip state. The pressing member 300 abuts against the inner circumferential surface of the second belt 21. The pressing member 300 supports the first belt 11 and the second belt 21 from the lower surface from the inner circumferential surface of the second belt 21. An opening 810 is provided in the heating region 241 of the pressing member 300. The thermoswitch 210 is a contact type temperature detection member. That is, the thermoswitch 210 protrudes partially from the opening 810. This brings the thermoswitch 210 into contact with the second belt 21. Then, the thermoswitch 210 detects the temperature of the surface of the second belt 21 that contacts the pressing member 300, thereby monitoring abnormal heating of the first belt 11 and the second belt 21 by the on-demand heater 110.

[0035] The reason why opening 810 is provided in pressing member 300 to monitor the belts from below is as follows. It is desired to monitor the state of first belt 11 and second belt 21 heated by on-demand heater 110 with thermoswitch 210 via pressing member 300. However, pressing member 300 is made of a thick metal or the like and has a relatively large heat capacity. Therefore, the temperature rise of pressing member 300 is slower than that of the belts. As a result, the belt temperature cannot be detected with good responsiveness. Therefore, opening 810 is provided so that thermoswitch 210 can monitor the belt temperature without going through pressing member 300.

[0036] In addition, the temperature detection surface of the thermoswitch 210 is slightly protruded toward the second belt 21 side from the surface where the pressing member 300 and the second belt 21 contact each other, and is installed so as to always come into contact with the lower belt 201. This improves thermal conductivity, making it possible to detect the belt temperature with good responsiveness.

[0037] Furthermore, a temperature detection member 210 (thermoswitch 210) may be arranged between the upstream end and downstream end of the reflector 111 in the sheet conveying direction. This allows the temperature detection member 210 to be arranged in a range where the temperature rises more, and allows the temperature of the second belt to be detected with high accuracy.

[0038] 4 is a view of the nip portion where the sheet S is sandwiched, conveyed and heated between the first belt 11 and the second belt 21 in the first embodiment, as viewed from the bottom of the pressing member 300. Openings 810, 820 and 830 are provided within heating ranges 241, 242 and 243 by the on-demand heaters 110, 120 and 130 of the pressing member 300. Thermoswitches 210, 220 and 230 are installed at the positions of the openings 810, 820 and 830 so as to detect the temperature of the surface of the second belt 21 that comes into contact with the pressing member 300.

[0039] 5 is a control block diagram of the fixing system in Example 1. Fig. 5(a) is a control block diagram of the upper fixing belt system 10. The upper fixing belt system 10 is composed of a CPU 1100, a Relay 1200, control circuits 112, 122, and 132, on-demand heaters 110, 120, and 130, a temperature adjustment temperature sensor 310, thermoswitches 210, 220, and 230, and a rotation detection sensor 100.

[0040] The CPU 1100 controls the control circuits 112, 122, 132 based on the temperature information from the temperature sensor 310 to adjust the power supplied to the on-demand heaters 110, 120, 130, thereby adjusting the temperature. The thermoswitches 210, 220, 230 are connected in series to the lines that supply power to the on-demand heaters 110, 120, 130, and are normally in a conductive state. However, when the thermoswitches 210, 220, 230 detect a temperature exceeding a threshold value due to abnormal heating of the on-demand heaters 110, 120, 130, they are turned off. In other words, the power supply to the on-demand heaters 110, 120, 130 is forcibly cut off. The current detection unit 710 is connected in series to the lines that supply power to the on-demand heaters 110, 120, 130, and transmits the detection result of the supplied current to the CPU 1100. Relay 1200 is connected in series to the line that supplies power to on-demand heaters 110, 120, and 130, supplies power when in the on state, stops power supply when in the off state, and is controlled to be turned on and off by CPU 1100. Rotation detection sensor 100 monitors the rotation state of first belt 11, and if it detects that the first belt has stopped, it outputs a signal indicating the stopped state to CPU 1100, and upon receiving this, CPU 1100 turns Relay 1200 off.

[0041] 5B is a control block diagram of the lower fixing belt system 20. The lower fixing belt system 20 is composed of a CPU 2100, a relay 2200, control circuits 412 and 422, a temperature sensor 610 for adjusting the temperatures of the lower belt heaters 410 and 420, thermoswitches 510 and 520, and a rotation detection sensor 200.

[0042] The CPU 2100 controls the control circuits 412, 422 based on temperature information from the temperature sensor 610 to adjust the power supplied to the lower belt heaters 410, 420, thereby adjusting the temperature. The thermoswitches 510, 520 are connected in series to the line that supplies power to the lower belt heaters 510, 520, and are normally in a conductive state. However, when the thermoswitches 510, 520 detect a temperature exceeding a threshold due to abnormal heating of the lower belt heaters 410, 420, the thermoswitches 510, 520 are in a disconnected state. In other words, the power supply to the lower belt heaters 410, 420 is forcibly cut off. The current detection unit 810 is connected in series to the line that supplies power to the lower belt heaters 410, 420, and transmits the detection result of the supplied current to the CPU 2100. The relay 2200 is connected in series to the line that supplies power to the lower belt heaters 410, 420, supplies power when in the on state, stops the power supply when in the off state, and is controlled to be turned on and off by the CPU 2100. The rotation detection sensor 200 monitors the rotation state of the second belt 21, and when it detects a stop, it outputs a signal indicating the stop state to the CPU 2100, and the CPU 2100 receiving the signal turns off the Relay 2200.

[0043] 6A and 6B are control flowcharts of the fixing system in the embodiment 1. Fig. 6(a) is a control flowchart of the upper fixing belt system 10.

[0044] When the control of the upper fixing belt system 10 starts, the process proceeds to S101.

[0045] In S101, the CPU 1100 controls the driving roller 104 of the upper belt to rotate the first belt 11, starts the heating control of the on-demand heaters 110, 120, and 130, and then proceeds to S102.

[0046] In S102, the CPU 1100 adjusts the output of the on-demand heaters 110, 120, and 130 based on temperature information from the temperature adjustment sensor 310 to adjust the temperature of the first belt 11. The belt temperature is adjusted to a constant temperature to maintain the quality of the print medium. Then, the process proceeds to S103.

[0047] In S103, it is determined whether the first belt 11 is rotating based on the value of the rotation detection sensor 100. If the CPU 1100 determines from the value of the rotation detection sensor 100 that the first belt 11 is rotating, the process proceeds to S104. If the CPU 1100 determines from the signal of the rotation detection sensor 100 that the first belt 11 is not rotating, the process proceeds to S106.

[0048] In S104, it is determined whether or not a current is flowing to the on-demand heaters 110, 120, 130 based on the value of the current detection unit 710, and if it is determined that a current is flowing, the process proceeds to S105. If it is determined that a current is not flowing, it is determined that one of the thermo switches 210, 220, 230 is disconnected, indicating an abnormal state, and the process proceeds to S106.

[0049] In S105, the CPU 1100 determines whether or not a print job end notification has been received from a print job controller (not shown). If a print job end notification has been received, the process proceeds to S106. If a print job end notification has not been received, the process proceeds to S102.

[0050] In S106, the heating control of the on-demand heaters 110, 120, and 130 is stopped, the rotation of the first belt 11 is stopped, and the control is ended.

[0051] FIG. 6B is a control flowchart of the lower fixing belt system 20.

[0052] When the control of the lower fixing belt system 20 starts, the process proceeds to S201.

[0053] In S201, the CPU 2100 controls the drive roller 204 of the lower belt to rotate the second belt 21, starts the heating control of the lower belt heaters 410 and 420, and proceeds to S202.

[0054] In S202, the CPU 2100 adjusts the output of the lower belt heaters 410, 420 based on temperature information from the temperature adjustment sensor 610 to adjust the temperature of the second belt 21. The belt temperature is adjusted to a constant temperature to maintain the quality of the print medium. Then, the process proceeds to S203.

[0055] In S203, it is determined whether the second belt 21 is rotating based on the value of the rotation detection sensor 200. If the CPU 2100 determines from the value of the rotation detection sensor 200 that the upper belt 21 is rotating, the process proceeds to S204. If the CPU 2100 determines from the signal of the rotation detection sensor 200 that the belt is not rotating, the process proceeds to S206.

[0056] In S204, it is determined whether or not a current is flowing to the lower belt heaters 410, 420 based on the value of the current detection unit 810, and if it is determined that a current is flowing, the process proceeds to S205. If it is determined that a current is not flowing, it is determined that an abnormal state has occurred in which one of the thermo switches 510, 520 is disconnected, and the process proceeds to S206.

[0057] In S205, the CPU 2100 determines whether or not a print job end notification has been received from a print job controller (not shown). If a print job end notification has been received, the process proceeds to S206. If a print job end notification has not been received, the process proceeds to S202.

[0058] In S206, the heating control of the lower belt heaters 410, 420 is stopped, the rotation of the second belt 21 is stopped, and the control is ended.

[0059] The thermoswitch operates regardless of the control flow shown in FIG.

[0060] As a result, abnormal heating can be detected with good responsiveness in the on-demand fixing method.

[0061] Incidentally, a rounded edge may be formed on the side of the opening 810 that slides against the second belt 21. The formation of the opening 810 causes so-called edge contact, where the edge of the opening slides against the second belt. To prevent this, a rounded edge may be applied to the pressing member 300 in the portion where the opening 810 is formed. The rounded edge may be applied on the downstream side in the conveying direction of the belt.

[0062] Moreover, since the pressing member 300 is made of metal and slides against the second belt 21, the surface of the pressing member 300 may be provided with an uneven shape in order to improve the sliding property.

[0063] <Example 2> The overall configuration diagram, block diagram, and flow chart are the same as those in the first embodiment.

[0064] 7 is a side view of the heating parts of the three on-demand heaters in the second embodiment, and will be described using the on-demand heater 110 as a representative example of the differences from FIG. 3 in the first embodiment. The heating parts of the on-demand heaters 120 and 130 and the thermoswitches 220 and 320 have the same positional relationship.

[0065] The temperature detection surface of the thermoswitch 210 is slightly lowered below the surface where the pressing member 300 and the second belt 21 contact each other, and is installed at a position spaced a certain distance from the second belt 21. This makes it possible to detect the temperature of the fixing belt without worrying about wear of both the second belt 21 and the thermoswitch 210 due to friction between them.

[0066] <Example 3> The third embodiment is a fixing system in which the thermoswitches 210, 220, 230 and the thermoswitches 510, 520 used in the first embodiment are replaced with abnormality detection temperature sensors 211, 221, 231 and abnormality detection temperature sensors 511, 521, respectively.

[0067] Fig. 8 is a control block diagram of the fixing system in the third embodiment. Fig. 8(a) is a control block diagram of the upper fixing belt system 10. The upper fixing belt system 10 is composed of a CPU 1100, a Relay 1200, control circuits 112, 122, 132, and on-demand heaters 110, 120, 130. Furthermore, the upper fixing belt system 10 is composed of a temperature adjustment temperature sensor 310, abnormality detection temperature sensors 211, 221, 231, abnormal temperature detection circuits 212, 222, 232, and a rotation detection sensor 100.

[0068] The CPU 1100 controls the control circuits 112, 122, 132 based on the temperature information from the temperature sensor 310 to adjust the power supplied to the on-demand heaters 110, 120, 130, thereby adjusting the temperature. The abnormality detection temperature sensors 211, 221, 231 monitor the heating state of the on-demand heaters 110, 120, 130, and transmit the temperature information to the abnormality temperature detection circuits 212, 222, 232. The abnormality temperature detection circuits 212, 222, 232 compare the temperature information from the abnormality detection temperature sensors 211, 221, 231 with a predetermined threshold value. If the temperature information exceeds the threshold value, a signal for forcibly stopping the control circuits 112, 122, 132 is output to the control circuits 112, 122, 132 and the CPU 1100. In this case, the control circuits 112, 122, 132 are forcibly stopped, and the power supply to the on-demand heaters 110, 120, 130 is cut off. The forced stop signal is latched, and the power supply continues to be cut off even if the temperature drops. Relay 1200 is connected in series to the line that supplies power to on-demand heaters 110, 120, and 130, supplies power when in the on state, stops the power supply when in the off state, and is controlled to be turned on and off by CPU 1100. Rotation detection sensor 100 monitors the rotation state of first belt 11, and if it detects a stop, it outputs a signal indicating the stop state to CPU 1100, and upon receiving this, CPU 1100 turns Relay 1200 off.

[0069] 8(b) is a control block diagram of the lower fixing belt system 20. The upper fixing belt system 10 is composed of a CPU 2100, a Relay 2200, control circuits 411 and 421, and lower belt heaters 410 and 420. The upper fixing belt system further comprises a temperature adjustment temperature sensor 610, abnormality detection temperature sensors 511 and 521, abnormal temperature detection circuits 512 and 522, and a rotation detection sensor 200.

[0070] The CPU 2100 controls the control circuits 412, 422 based on temperature information from the temperature sensor 610 to adjust the power supplied to the lower belt heaters 410, 420, thereby adjusting the temperature. The abnormality detection temperature sensors 511, 521 monitor the heating state of the lower belt heaters 410, 420, and transmit the temperature information to the abnormality temperature detection circuits 512, 522. The abnormality temperature detection circuits 512, 522 compare the temperature information from the abnormality detection temperature sensors 511, 521 with a predetermined threshold value, and output a signal to the control circuits 412, 422 and the CPU 2100 to forcibly stop the control circuits 412, 422 when the temperature information exceeds the threshold value. In this case, the control circuits 412, 422 are forcibly stopped and the power supply to the lower belt heaters 410, 420 is cut off. The forced stop signal is latched, and the power supply cut off continues even if the temperature drops. Relay 2200 is connected in series to the line that supplies power to lower belt heaters 410, 420, supplies power when in the on state, and stops power supply when in the off state, and is controlled to be turned on and off by CPU 2100. Rotation detection sensor 200 monitors the rotation state of upper belt 21, and when it detects that the upper belt 21 has stopped, it outputs a signal indicating the stopped state to CPU 2100, and upon receiving this, CPU 2100 turns Relay 2200 off.

[0071] 9A and 9B are control flowcharts of the fixing system in the embodiment 3. Fig. 9A is a control flowchart of the upper fixing belt system 10.

[0072] When the control of the upper fixing belt system 10 starts, the process proceeds to S501.

[0073] In S501, the CPU 1100 controls the driving roller 104 of the upper belt to rotate the first belt 11, starts the heating control of the on-demand heaters 110, 120, and 130, and then proceeds to S502.

[0074] In S502, the CPU 1100 adjusts the output of the on-demand heaters 110, 120, and 130 based on temperature information from the temperature adjustment sensor 310 to adjust the temperature of the first belt 11. The belt temperature is adjusted to a constant temperature to maintain the quality of the print medium. Then, the process proceeds to S503.

[0075] In S503, it is determined whether the first belt 11 is rotating based on the value of the rotation detection sensor 100. If the CPU 1100 determines from the value of the rotation detection sensor 100 that the first belt 11 is rotating, the process proceeds to S504. If the CPU 1100 determines from the signal of the rotation detection sensor 100 that the first belt 11 is not rotating, the process proceeds to S506.

[0076] In S504, the CPU 1100 checks whether an abnormal temperature has been detected from the input signals from the abnormal temperature detection circuits 212, 222, and 232, and if an abnormal temperature has not been detected, the process proceeds to S505. If an abnormal temperature has been detected, the process proceeds to S506.

[0077] In S505, the CPU 1100 determines whether or not a print job end notification has been received from a print job controller (not shown). If a print job end notification has been received, the process proceeds to S506. If a print job end notification has not been received, the process proceeds to S502.

[0078] In S506, the heating control of the on-demand heaters 110, 120, and 130 is stopped, the rotation of the first belt 11 is stopped, and the control is ended.

[0079] FIG. 9B is a control flowchart of the lower fixing belt system 20.

[0080] When the control of the lower fixing belt system 20 starts, the process proceeds to S601.

[0081] In S601, the CPU 2100 controls the driving roller 204 of the upper belt to rotate the second belt 21, starts the heating control of the lower belt heaters 410 and 420, and then proceeds to S602.

[0082] In S602, the CPU 2100 adjusts the output of the lower belt heaters 410, 420 based on temperature information from the temperature adjustment sensor 610 to adjust the temperature of the second belt 21. The belt temperature is adjusted to a constant temperature to maintain the quality of the print medium. The process proceeds to S603.

[0083] In S603, it is determined whether the upper belt 21 is rotating based on the value of the rotation detection sensor 200. If the CPU 2100 determines from the value of the rotation detection sensor 200 that the upper belt 21 is rotating, the process proceeds to S604. If the CPU 2100 determines from the signal of the rotation detection sensor 200 that the upper belt 21 is not rotating, the process proceeds to S606.

[0084] In S604, the CPU 2100 checks whether an abnormal temperature has been detected from the input signals from the abnormal temperature detection circuits 512 and 522, and if an abnormal temperature has not been detected, the process proceeds to S605. If an abnormal temperature has been detected, the process proceeds to S606.

[0085] In S605, the CPU 2100 determines whether or not a print job end notification has been received from a print job controller (not shown). If a print job end notification has been received, the process proceeds to S606. If a print job end notification has not been received, the process proceeds to S602.

[0086] In S606, the heating control of the lower belt heaters 410, 420 is stopped, the rotation of the second belt 21 is stopped, and the control is ended.

[0087] Fig. 10 is a flowchart of a forced stop by the abnormal temperature detection circuit of the fixing system in the third embodiment. Fig. 10(a) is a flowchart of a forced stop by the abnormal temperature detection circuit of the upper fixing belt system. The forced stop by the abnormal temperature detection circuit operates regardless of the sequence of the control flowchart in Fig. 8 described above. When the abnormal temperature detection circuit starts operation, the process proceeds to S701.

[0088] In S701, the abnormal temperature detection circuits 212, 222, and 232 compare the temperature information input from the abnormality detection temperature sensors 211, 221, and 231, respectively, with a predetermined threshold value, and if the threshold value is exceeded, the process proceeds to S702. If the threshold value is not exceeded, S701 is repeated.

[0089] In S702, the abnormal temperature detection circuits 212, 222, and 232 forcibly stop all the control circuits 112, 122, and 132. The process proceeds to S703.

[0090] In S703, the control circuits 112, 122, and 132 are all stopped, the power supply to the on-demand heaters 110, 120, and 130 is cut off, and the process ends.

[0091] 10B is a flow chart of the forced stop of the lower fixing belt system by the abnormal temperature detection circuit. When the abnormal temperature detection circuit starts operation, the process proceeds to S801.

[0092] In S801, the abnormal temperature detection circuits 512 and 522 compare the temperature information input from the abnormality detection temperature sensors 511 and 521, respectively, with a predetermined threshold, and if the threshold is exceeded, the process proceeds to S802. If the threshold is not exceeded, S801 is repeated.

[0093] In S802, the abnormal temperature detection circuits 512, 522 forcibly stop the control circuits 412, 422. The process proceeds to S803.

[0094] In S803, the control circuits 411 and 421 are all stopped, the power supply to the lower belt heaters 410 and 420 is cut off, and the process ends.

[0095] As a result, abnormal heating can be detected with good responsiveness in the on-demand fixing method.

[0096] <Example 4> The fourth embodiment is a fixing system in which the thermoswitches 210, 220, 230 and the thermoswitches 510, 520 used in the second embodiment are replaced with abnormality detection temperature sensors 211, 221, 231 and abnormality detection temperature sensors 511, 521, respectively.

[0097] As with the thermoswitch of the second embodiment, it is possible to detect the temperature of the fixing belt without worrying about wear of both the second belt 21 and the abnormality detection temperature sensors 211, 221, and 231 due to friction. [Explanation of symbols]

[0098] 1. Inkjet recording device 10. Upper fixing belt system 11... First belt 20. Lower fixing belt system 21...Second belt 210 Temperature sensing member 300 Pressing member 310 Temperature control sensor 810...Opening 2000 Print module 3000 Drying module 4000···Fixing module 4100....Fuser belt unit

Claims

1. A first belt for heating the seat; A heating means is disposed inside the first belt and heats the first belt in a non-contact manner; a second belt that contacts the first belt to form a nip portion with the first belt and fixes an ink image on the sheet to the sheet together with the first belt; a pressing member that contacts an inner circumferential surface of the second belt in the nip portion and presses the first belt via the second belt; The pressing member has an opening formed in a heating region heated by the heating means, a temperature detection member disposed in the opening and configured to detect a temperature of an inner circumferential surface of the second belt; An ink jet recording apparatus comprising:

2. The pressing member is made of metal.

2. The inkjet recording apparatus according to claim 1,

3. The heating means is provided in a plurality of units along the sheet conveying direction.

2. The inkjet recording apparatus according to claim 1,

4. A plurality of the temperature detection members are provided, The temperature detection member is disposed at a position corresponding to the heating regions of the plurality of heating means.

4. The inkjet recording apparatus according to claim 3,

5. The opening is rounded on the side that slides against the second belt.

2. The inkjet recording apparatus according to claim 1,

6. The surface of the pressing member on the side that slides against the second belt is provided with an uneven shape.

3. The inkjet recording apparatus according to claim 2,

7. The heating means has a reflector opening towards the heating area.

2. The inkjet recording apparatus according to claim 1,

8. the temperature detection member is a contact type temperature detection member that detects the temperature of the second belt by a portion of the temperature detection member protruding from the opening.

2. The inkjet recording apparatus according to claim 1,

9. the temperature detection member is disposed between an upstream end and a downstream end of the reflector in a sheet conveying direction; 8. The inkjet recording apparatus according to claim 7,

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