Ink jet recording apparatus

Abstract

To accurately detect the temperature of a heating region of a heater in a configuration in which an inner peripheral surface of a belt is heated by a non-contact heater.SOLUTION: An ink jet recording apparatus includes an ink image formation unit that forms an ink image on a recording material, and a fixing device that fixes the ink image onto the recording material. The fixing device includes: a first belt; a rotating body that forms a nip portion by coming into contact with the first belt; a heater that is disposed inside the first belt for heating the nip portion in a non-contact manner; a reflector that covers an upper part of the heater, reflects radiant heat from the heater toward an inner peripheral surface of the first belt at the nip portion, and has an opening; and a temperature detection member that is arranged on the inner side of the first belt and detects the temperature of the heating region of the heater on the first belt in a non-contact manner. The temperature detection member is disposed so as to detect the temperature of the first belt through the opening.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] If you touch a recording material immediately after it has been recorded by an inkjet recording device while the ink is still wet, the image may be distorted or the ink may get on your hands. Inkjet recording devices have a high recording speed, and a second sheet of recording material may be placed on top of the first before the ink on the first sheet has dried, causing the back side of the first sheet to become dirty. For this reason, inkjet recording devices, particularly high-speed recording models, require a means to dry the ink and fix it on the recording material.

[0003] Inkjet recording devices use a thermal fixing method in which the recording material is heated immediately after recording as a means for drying and fixing the ink. Patent Document 1 discloses a configuration in which a nip is formed by a pair of rollers to perform fixing.

[0004] In a configuration in which the recording material carrying the ink image is fixed by passing it through a nip portion formed by a pair of rollers, the width of the recording material in the conveying direction is small. Therefore, it is necessary to set the temperature of the fixing portion high. This can cause the ink image to evaporate, which can lead to image defects. For this reason, a configuration in which the nip portion is formed between belts has been proposed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication 2010-201817 Summary of the Invention [Problem to be solved by the invention]

[0006] A fixing device is proposed in which a nip is formed by a first belt that contacts the front side of a recording material on which an ink image is formed and a second belt that contacts the first belt. In the fixing device, a heater that is a heat source is disposed on the inner peripheral surface of the first belt without contacting the first belt.

[0007] If a heater is placed without contacting the first belt, the temperature of the first belt can be raised rapidly. However, it is necessary to detect the temperature of the belt area heated by the heater with high accuracy. Therefore, a temperature detection member that detects the temperature without contact is placed at an angle to detect the temperature of the belt area heated by the heater.

[0008] However, since a reflector is provided to concentrate the heat of the heater onto the first belt, there is a risk that the reflector will be within the viewing angle of the temperature detection member, making it difficult to detect the temperature with high accuracy.

[0009] An object of the present invention is to accurately detect the temperature of a region heated by a heater in a configuration in which the inner circumferential surface of a belt is heated by a non-contact heater. [Means for solving the problem]

[0010] In consideration of the above problems, an inkjet recording apparatus according to the present invention is characterized in that it includes an ink image forming unit that forms an ink image on a recording material, a fixing device that is arranged downstream of the ink image forming unit in the transport direction of the recording material and fixes the ink image to the recording material while sandwiching and transporting the recording material, the fixing device including a rotatable first belt that contacts the ink image formed by the ink image forming unit, a rotating body that forms a nip portion by abutting against the first belt, a heater that is arranged inside the first belt and heats the nip portion without contact, a reflector that covers an upper part of the heater and reflects radiant heat from the heater toward an inner surface of the first belt in the nip portion, the reflector has an opening formed therein, is arranged inside the first belt, and includes a temperature detection member that detects the temperature of the heated area of ​​the heater in the first belt without contact, and the temperature detection member is arranged so as to detect the temperature of the first belt through the opening. Effect of the Invention

[0011] According to the present invention, in a configuration in which the inner surface of the belt is heated by a non-contact heater, by accurately detecting the temperature of the heating area of ​​the heater, excessive heating of the belt can be suppressed when the heater goes out of control. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an inkjet recording apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a diagram showing the overall configuration of a fixing device; [Diagram 3] FIG. 1 is a block diagram showing a system configuration for detecting abnormal temperatures in a fixing device; [Figure 4] 10 is a flowchart illustrating fixing control of the fixing device. [Diagram 5] 1 is a diagram showing the structure and viewing angle of a temperature sensor 210. [Figure 6] FIG. 1 is a diagram showing a conventional example. [Figure 7] 1 is a diagram showing the arrangement of a temperature sensor 210 and the shape of a reflector 111 according to a first embodiment; [Figure 8] 13 is a diagram showing the arrangement of a temperature sensor 210 and the shape of a reflector 111 according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Example 1> The present embodiment will be described with reference to the drawings. First, a schematic configuration of an image forming system according to the present embodiment will be described with reference to FIG.

[0014] <Image forming system> The inkjet recording apparatus 1 of this embodiment uses an inkjet recording method in which ink is ejected to form an image on a recording material. An ink image is formed on the recording material using two liquids, a reaction liquid and ink. The recording material S may be any recording material capable of receiving ink, such as plain paper, thick paper, plastic film for overhead projectors, recording materials in special shapes such as envelopes and index paper, and cloth.

[0015] 1, an inkjet recording apparatus 1 of this embodiment is an example of an image forming apparatus, and includes a feeding module 1000, an ink image forming unit 2000, and a drying module 3000. The inkjet recording apparatus 1 further includes a fixing device 4000, a cooling module 5000, an inverting module 6000, and a stacking module 7000. The recording material S supplied from the feeding module 1000 is subjected to various processes while being transported along a transport path in each module, and is finally discharged to the stacking module 7000.

[0016] The feeding module 1000 to the loading module 7000 may each have a separate housing, and these housings may be connected to configure the inkjet recording apparatus 1. Alternatively, the feeding module 1000 to the loading module 7000 may be arranged in a single housing.

[0017] The feeding module 1000 has storage chambers 1100a, 1100b, and 1100c for storing recording materials S, and the storage chambers 1100a to 1100c are provided so as to be able to be pulled out toward the front side of the apparatus in order to store the recording materials S. The recording materials S are fed one by one in each of the storage chambers 1100a to 1100c by a separation belt and a conveying roller, and conveyed to the ink image forming unit 2000. Note that the feeding module 1000 is not limited to a configuration having three storage chambers 1100a to 1100c, and may be a configuration having one, two, or four or more storage chambers.

[0018] The ink image forming unit 2000 has a pre-image registration correction unit, a print belt unit 2200, and a recording unit 2300, and ejects ink onto the recording material S to form an ink image. The recording material S conveyed from the feeding module 1000 has its inclination and position corrected by the pre-image registration correction unit, and is conveyed to the print belt unit 2200. The recording unit 2300 is disposed at a position facing the print belt unit 2200 with respect to the conveying path. The recording unit 2300 is an inkjet recording unit that forms an ink image by ejecting ink onto the conveyed recording material S from above using a recording head. A plurality of recording heads that eject 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 recording material S is adsorbed and conveyed by the print belt unit 2200, so that a clearance between the recording head and the recording material S is ensured.

[0019] The number of ink colors and recording heads are not limited to the above five. The inkjet method may be a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical Systems) 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.

[0020] When the recording material S on which an image is formed by the recording section 2300 is transported by the print belt unit 2200, it is detected by an in-line scanner (not shown) arranged downstream of the recording section 2300 in the transport direction of the recording material S. Here, the misalignment and color density of the image formed on the recording material S are detected, and the image formed on the recording material S, density, etc. are corrected based on the misalignment and color density of the image.

[0021] The drying module 3000 is an example of a drying device, and dries the recording material S on which an image is formed by ejecting ink by blowing hot air onto the recording material S. The drying module 3000 has a decoupling section 3200, a drying belt unit 3300, and a hot air blowing unit 3400. The drying module 3000 reduces the liquid content of the ink and reaction liquid applied to the recording material S in order to improve the fixation of the ink to the recording material S by the subsequent fixing device 4000. The recording material S on which the image is formed is transported to the decoupling section 3200 arranged in the drying module 3000. In the decoupling section 3200, a frictional force is generated between the recording material S and the belt by the wind pressure of the wind blown from above, and the recording material S is transported by the belt. In this way, the recording material S placed on the belt is transported by the frictional force, thereby preventing the recording material S from shifting when the recording material S is transported between the print belt unit 2200 and the decoupling section 3200. The recording material 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 recording material S are dried by hot air blown onto it from the hot air blowing unit 3400 arranged above the belt.

[0022] In this way, the ink and reaction liquid applied to the recording material S are heated by the drying module 3000, accelerating the evaporation of moisture. This makes it possible to suppress the occurrence of so-called cockling, in which the ink applied to the recording material S absorbs the ink and the paper locally stretches and wrinkles. As a heater for heating the air, for example, heating by an electric heating wire or an infrared heater is preferable from the standpoint of safety and energy efficiency. Furthermore, the drying method may be configured by combining a method of applying hot air, a method of irradiating the surface of the recording material S with electromagnetic waves (ultraviolet rays, infrared rays, etc.), and a conductive heat transfer method by contact with a heating element.

[0023] The fixing device 4000 has a fixing belt unit 4100. The fixing belt unit 4100 passes the recording material S, on which an image has been formed and which has been conveyed from the drying module 3000, through a nip portion formed between a heated first belt unit and a second belt unit. As a result, the ink image is fixed onto the recording material S.

[0024] The cooling module 5000 has a plurality of cooling sections 5003, which cool the high-temperature recording material S transported from the fixing device 4000. The cooling sections 5003, for example, take in outside air into a cooling box with a fan to increase the pressure inside the cooling box, and cool the recording material S by blowing air from the cooling box through a nozzle due to the pressure onto the recording material S. The cooling sections 5003 are disposed on both sides of the transport path of the recording material S, and cool both sides of the recording material S.

[0025] The cooling module 5000 is provided with a transport path switching unit 5004. The transport path switching unit 5004 switches the transport path of the recording material S depending on whether the recording material 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 recording material S.

[0026] The inversion module 6000 has an inversion section 6400. The inversion section 6400 inverts the recording material S being conveyed, and changes the orientation of the recording material 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 recording material S conveyed from the inversion module 6000.

[0027] During double-sided printing, the recording material S is conveyed to a conveying path below the cooling module 5000 by the conveying path switching unit 5004. Thereafter, the recording material S passes through a double-sided conveying path including the fixing device 4000, the drying module 3000, the ink image forming unit 2000, and the feeding module 1000, and is returned to the ink image forming unit 2000. The double-sided conveying unit of the fixing device 4000 is provided with an inverting unit 4200 that inverts the recording material S. The recording material S returned to the ink image forming unit 2000 has an image formed with ink on the other side on which no image is formed, and is then discharged from the drying module 3000 through the inverting module 6000 to the stacking module 7000.

[0028] <Fixing device> 2 is an overall configuration diagram including a first belt unit 10 and a second belt unit 20 of a fixing device 4000 in an inkjet recording apparatus. The inkjet recording apparatus prints inkjet onto a recording material S, dries moisture in the inkjet, and fixes the ink. A rotatable first belt 11 of the first belt unit 10 is heated by a heat source, and comes into contact with and heats the recording material S. A rotatable second belt 21 of the second belt unit comes into contact with the first belt 11 to form a nip portion. The first belt 11 and the second belt 21 sandwich and transport the recording material S, and fix the recording material S.

[0029] The first belt 11 and the second belt 21 are rotated by drive motors (not shown) which are their respective drive sources, and the recording material S is transported in the direction of the arrow. A drive motor is connected to the first drive roller 720 and driven to rotate, thereby rotating the first belt 11. A drive motor is connected to the second drive roller 740 and driven to rotate, thereby rotating the second belt 21. The first drive roller and the second drive roller are rubber rollers with rubber surfaces. Being rubber rollers, they have an increased grip on the belt, enabling the belt to be transported stably.

[0030] <First belt unit> The first belt unit 10 includes heaters 110, 120, and 130, a first driving roller 720, temperature sensors 210, 220, and 230 that are temperature detection members disposed within the first belt, and a temperature sensor 310 that adjusts the temperature of the belt.

[0031] The first belt 11 comes into contact with the front surface of the recording material S on which ink has been applied by the ink image forming unit 2000. In order to heat the ink image on the recording material S, a first heater unit 160 is arranged to heat the inner circumferential surface of the first belt 11 without contact. The first heater unit has heaters 110, 120, and 130 which are halogen heaters, and the heaters 110, 120, and 130 heat the inner circumferential surface of the first belt without contact. The heaters 110, 120, and 130 are arranged side by side along the conveying direction of the recording material S. Furthermore, the heaters 110, 120, and 130 heat the nip portion formed by the first belt 11 and the second belt 21. Therefore, the heaters 110, 120, and 130 arranged inside the first belt are arranged side by side along the conveying direction in the nip portion. The nip portion of this embodiment is configured to be wide in the conveying direction so that it can be arranged along such a conveying direction.

[0032] 3 is a hardware block diagram of the fixing device 4000. FIG. 3(a) shows a hardware block diagram of the first belt unit 10.

[0033] The CPU 1100 controls the outputs of the heaters 110, 120, and 130 by driving the FETs 111, 121, and 131. The CPU 1100 adjusts the output amounts of the heaters 110, 120, and 130 by feeding back temperature information from a temperature sensor 310.

[0034] The abnormal temperature detection hardware 211, 221, 231 detects that the temperature of the temperature sensor 210, 220, 230 is equal to or higher than a certain threshold, and stops driving the FET 111, 121, 131. The abnormal temperature threshold is a temperature set according to the material of the belt to prevent deformation, and is set to 150° C. in this embodiment, but is not limited to this. The CPU 1100 controls the temperature of the belt 11 by driving the FET 111, 121, 131 based on the temperature detected by the temperature sensor 310. When the thermo switches 1110, 1210, 1310 detect abnormal heating temperatures of the heaters 110, 120, 130, they cut off the power supply to the heaters 110, 120, 130. The rotation detection sensor 100 detects the stop of rotation of the belt 11 and cuts off the relay 1200 to stop heating the heaters 110, 120, 130.

[0035] 3B is a hardware block diagram of the second belt unit 20. The second belt unit 20 is composed of a CPU 2100, a Relay 2200, FETs 411 and 421, abnormal temperature detection hardware 511 and 521, heaters 410 and 420, temperature sensors 510 and 520, and a temperature sensor 610. The CPU 2100 controls the output of the heaters 410 and 420 by driving the FETs 411 and 421. The CPU 2100 adjusts the output amount of the heaters 410 and 420 by feeding back temperature information from the temperature sensor 510.

[0036] The abnormal temperature detection HW 511, 521 detects when the temperatures of the temperature sensors 510, 520 exceed a certain threshold value, and stops driving the FETs 411, 421. The abnormal temperature threshold value is a temperature that is set in accordance with the material of the belt to prevent deformation, and is set to 150° C. in this embodiment, but is not limited to this.

[0037] The CPU 2100 adjusts the drive control of the FETs 511 and 521 that control the heaters 410 and 420 based on temperature information from the temperature sensor 610. The rotation detection sensor 200 detects that the belt 21 has stopped rotating and cuts off the relay 2200, thereby causing the heaters 410 and 420 to stop heating.

[0038] Fig. 4 is a flowchart of the fixing control of the fixing device. Fig. 4(a) is a flowchart of the fixing control of the first belt unit 10. The fixing control of the fixing device 4000 will be described.

[0039] When the fixing control is started in the first belt unit 10, the process proceeds to S301.

[0040] In S301, the CPU 1100 controls the drive motor for the upper belt to rotate the belt and turn on the heaters 110, 120, and 130.

[0041] In S302, the CPU 1100 reads the value of the temperature sensor 310 and controls the heaters 110, 120, and 130 to adjust the temperature of the belt. The temperature of the belt is adjusted to a constant temperature in order to maintain the quality of the print medium.

[0042] In S303, CPU 1100 determines whether the belt is rotating based on the value of rotation detection sensor 100. If CPU 1100 determines from the value of rotation detection sensor 100 that the belt is rotating, the process proceeds to S304. If CPU 1100 determines from the value of rotation detection sensor 100 that the belt is not rotating, the process proceeds to S306.

[0043] In S304, the CPU 1100 determines whether the temperature values ​​read from the temperature sensors 210, 220, 230 are higher than a certain threshold temperature. In this embodiment, the threshold temperature is set to 150° C. In S304, if the temperature values ​​read from the temperature sensors 210, 220, 230 by the CPU 1100 are higher than the threshold temperature of 150° C., the process proceeds to S306. In S304, if the temperature values ​​read from the temperature sensors 210, 220, 230 by the CPU 1100 are lower than the threshold temperature of 150° C., the process proceeds to S305.

[0044] In S305, 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 in S305, the process proceeds to S306. If a print job end notification has not been received in S305, the process proceeds to S302.

[0045] In S306, the CPU 1100 controls the drive motor for the upper belt to stop the rotation of the belt, and the heaters 110, 120, and 130 are stopped.

[0046] It should be noted that the threshold temperature of 150° C. in this embodiment is merely an example, and is not limited to this.

[0047] 4B is a flowchart of the fixing control of the second belt unit 20. The fixing control of the second belt unit will be described.

[0048] When the fixing control is started in the second belt unit 20, the process proceeds to S401.

[0049] In S401, the CPU 2100 controls the drive motor for the upper belt to rotate the belt and turn on the heaters 410 and 420.

[0050] In S402, the CPU 2100 reads the value of the temperature sensor 610 and controls the heaters 410 and 420 to adjust the temperature of the belt. The temperature of the belt is adjusted to a constant temperature in order to maintain the quality of the print medium.

[0051] In S403, the CPU 2100 determines whether the belt 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 belt is rotating, the process proceeds to S404. If the CPU 2100 determines from the value of the rotation detection sensor 200 that the belt is not rotating, the process proceeds to S406.

[0052] In S404, the CPU 2100 determines whether the temperature values ​​read from the temperature sensors 210, 220, 230 are higher than a certain threshold temperature. In this embodiment, the threshold temperature is set to 150° C. In S404, if the temperature values ​​read from the temperature sensors 510, 520 by the CPU 2100 are higher than the threshold temperature of 150° C., the process proceeds to S406. In S404, if the temperature values ​​read from the temperature sensors 510, 520 by the CPU 2100 are lower than the threshold temperature of 150° C., the process proceeds to S405.

[0053] In S405, 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 in S405, the process proceeds to S406. If a print job end notification has not been received in S405, the process proceeds to S402.

[0054] In S406, the CPU 2100 controls the drive motor of the lower belt to stop the rotation of the belt, and the heaters 410 and 420 are stopped.

[0055] It should be noted that the threshold temperature of 150° C. in this embodiment is merely an example, and is not limited to this.

[0056] FIG. 5 is a diagram for explaining the configuration of the temperature sensor 210. FIG. 5(a) is an external view of the temperature sensor 210. FIG. 5(b) and FIG. 5(c) are diagrams for explaining the viewing angle of the temperature sensor 210. The package 3001 is a package in which a sensor module is built in, is mounted on a substrate 2111, and has a detection window 3002 at the top. The temperature sensor 210 absorbs infrared rays emitted from a measurement object through the detection window 3002 and converts the absorbed infrared energy into an electrical signal, thereby enabling non-contact temperature detection. FIG. 5(b) is a diagram for illustrating the viewing angle of the temperature sensor 210. The detection window 3002 not only passes infrared rays into the inside of the package 3001, but also plays a role as a lens. That is, the temperature sensor 210 has a certain viewing angle 3004, and detects the temperature of a measurement object 3003 within the viewing angle 3004 in a non-contact manner. FIG. 5(c) is a diagram for explaining the definition of the viewing angle 3004. The temperature measurement accuracy is set to 100% when the measurement object 3003 is located on the center line 3005 of the viewing angle 3004. Next, the measurement object 3003 is moved from the center line 3005 without changing the distance from the temperature sensor 210. When the temperature measurement accuracy drops to 50% due to the movement, the angle θ formed by the measurement object 3003 and the center line 3005 is defined as the viewing angle 3004. Note that the value of 50% in this embodiment is merely an example and is not limited to 50%.

[0057] FIG. 6 is a diagram showing a conventional example of the arrangement of the temperature sensor 210. FIG. 6(a) shows an example of the arrangement of the temperature sensor 210. The reflector 111 reflects the radiant heat emitted from the heater 110 and focuses it toward the belt 11 to heat it. A certain area of ​​the belt 11 is heated (heated area) according to the shape of the reflector 111. The heating range 4000 has a distribution 400 of heating intensity according to the shape of the reflector 111. The center 401 of the light focused by the reflector 111 has a stronger heating intensity, and the heating intensity decreases when it is away from the center 401. In this embodiment, the range where the radiant heat from the heater 110 reaches the first belt 11 is defined as the heating area 4000a. The temperature sensor 210 is disposed at a position outside the heating range 4000 of the heater 110. The center line 3005 of the viewing angle 3004 of the temperature sensor 210 faces the center 401 of the light collected by the reflector 111, that is, the point of strongest heating intensity on the distribution 400 of heating intensity. The temperature sensor 210 is also disposed so that the reflector 111 does not interfere with the viewing angle 3004. In the example of FIG. 6(a), not only does the viewing angle 3004 not fall within the heated region 4000a, but even the far right side of the heated region 4000a in the figure falls within the viewing angle 3004. In this way, when a region other than the target of temperature detection falls within the viewing angle 3004, a problem occurs in that the temperature of the belt heating surface cannot be detected accurately.

[0058] FIG. 6(b) shows another example of the arrangement of the temperature sensor 210. In the example of FIG. 6(b), the temperature sensor 210 is arranged further upward in order to fit the heated region 4000a, which is the temperature detection target, within the viewing angle 3004. In this way, by making the angle between the center line 3005 of the viewing angle 3004 of the temperature sensor 210 and the belt 11 larger, it is possible to fit the heated region 4000a within the viewing angle 3004 as much as possible. However, as shown in the figure, if the temperature sensor 210 is arranged to be angled upward, a problem occurs in that the viewing angle 3004 and the reflector 111 interfere with each other. The interference causes a problem in that the temperature of the heated region 4000a cannot be detected accurately.

[0059] FIG. 7 is a diagram showing a suitable arrangement of the temperature sensor 210 and a shape of the reflector 111 for solving the problem described in FIG. 6. In FIG. 7(a), the temperature sensor 210 is arranged outside the heating region 4000a, and the center line 3005 faces the center 401 of the light collected by the reflector 111, as in FIG. 5. The difference between the example of FIG. 6 and the example of FIG. 7(a) is that an opening 5002 is formed in the reflector 111. The opening 5002 in this embodiment is a cutout in which the lower end of the reflector in the vertical direction is cut out. By cutting out the lower end of the reflector 111, it is possible to suppress interference between the viewing angle 3004 and the reflector 111. Note that a part of the radiant heat radiated from the heater 110 leaks from the cutout portion 5002. Therefore, the temperature sensor 210 needs to be arranged upward, that is, in a position that is in a blind spot from the heater 110, so that the sensor body is not directly heated by the leaked radiant heat. For example, the temperature sensor 210, which is a temperature detection member, is disposed outside the reflector 111, and further disposed vertically above the lower end of the reflector 111 where the opening 5002 is formed.

[0060] FIG. 7B is a bird's-eye view of the reflector 111 from the temperature sensor 210 side. The reflector 111 has a cutout portion 5002 at the position where the temperature sensor 210 is attached. In this embodiment, the cutout portion 5002 is formed at the center in the width direction of the reflector 111. The center in the width direction is an area through which the smallest size recording material in the width direction passes. Therefore, the heater heats the center during image formation regardless of the width direction size of the recording material. Therefore, it is necessary to dispose the temperature sensor 210 at the center in the width direction, and it is preferable to form the opening 5002 at the center in the width direction as well. In this way, by providing the cutout portion 5002 only at the position where the temperature sensor 210 is attached, rather than over the entire width direction of the belt 11, it is possible to minimize the influence on the light collecting performance of the reflector 111.

[0061] As described above, according to this embodiment, by providing the opening 5002 in a part of the reflector 111, it is possible to arrange the temperature sensor 210 without reducing the belt temperature measurement accuracy. Note that this embodiment is merely an example, and the embodiment is not limited to the configuration described here. The position of the notch 5002 in the belt width direction, the number, and the size of the notch are not limited to this. In addition, in this embodiment, the temperature sensor 210 and the notch 5002 are arranged on the left side of the reflector 111 in the figure, that is, downstream of the reflector 111 in the moving direction of the belt 11. However, it is sufficient that the temperature sensor 210 and the notch 5002 are arranged on the right side of the reflector 111 in the figure, that is, at least one of the upstream and downstream ends in the conveying direction of the recording material with respect to the reflector 111.

[0062] <Example 2> In the first embodiment, an example is shown in which the notch 5002 is provided at the lower end of the reflector 111. In the second embodiment, another example of the position and shape of the notch is shown.

[0063] Fig. 8 is a diagram showing a suitable arrangement of the temperature sensor 210 and the shape of the reflector 111 in Example 2. In Fig. 8(a), the temperature sensor 210 is arranged outside the heating region 4000a, the center line 3005 faces the center 401 of light collection by the reflector 111, and the reflector 111 does not interfere with the viewing angle 3004, which is similar to Fig. 6(a). The difference from Fig. 6(a) is that an opening 6002 on the left side of the reflector 111 is in the shape of a window, which will be described later.

[0064] As in the first embodiment, the temperature sensor 210 must be disposed above, that is, in a blind spot from the heater 110, so that the sensor body is not directly heated by radiant heat leaking from the opening 6002.

[0065] 8(b) is a diagram of the reflector 111 viewed from the side of the temperature sensor 210. The reflector 111 is similar to the first embodiment in that it has an opening 6002 at the position where the temperature sensor 210 is attached.

[0066] As described above, according to this embodiment, the temperature sensor 210 can be more suitably arranged by providing a window-shaped opening 6002 in a part of the reflector 111. As a result, even if the viewing angle 3004 of the temperature sensor 210 is wider than that of the first embodiment, the heated area 4000a, which is the temperature detection target, can be accommodated within the viewing angle 3004. Note that this embodiment is merely an example, and the present embodiment is not limited to the configuration described here. The position of the opening 6002 in the belt width direction, the number of openings, and the size of the notch are not limited to this. In addition, the shape of the opening 6002 is not limited to a rectangle, and may be a circle, a triangle, or a polygon. In this embodiment, the temperature sensor 210 and the opening 6002 are arranged on the left side of the reflector 111 in the figure, that is, on the downstream side of the movement direction of the belt 11 with respect to the reflector 111. However, it is sufficient that the temperature sensor 210 and the opening 6002 are arranged on the right side of the reflector 111 in the figure, that is, at least one of the upstream and downstream ends in the conveying direction of the recording material with respect to the reflector 111. [Explanation of symbols]

[0067] 10 First belt unit 11 First Belt 20 Second belt unit 21 Second Belt 110,120,130 Heater 111,121,131 Reflector 210,220,230 Temperature Sensors 4000 Fixing device 5002 Opening

Claims

1. an ink image forming unit that forms an ink image on a recording material; a fixing device disposed downstream of the ink image forming unit in a conveying direction of the recording material, the fixing device fixing the ink image onto the recording material while nipping and conveying the recording material; The fixing device is a first belt that is rotatable and contacts the ink image formed by the ink image forming section; a rotating body that forms a nip portion by contacting the first belt; a heater disposed inside the first belt and configured to heat the nip portion in a non-contact manner; a reflector that covers an upper portion of the heater and reflects radiant heat from the heater toward an inner circumferential surface of the first belt in the nip portion; The reflector has an opening formed therein, a temperature detection member disposed inside the first belt and configured to detect a temperature of the first belt in a non-contact manner in a region heated by the heater; the temperature sensing member is positioned to sense the temperature of the first belt through the opening; 1. An ink jet recording apparatus comprising:

2. the opening is a notch formed in one of an upstream end and a downstream end of the reflector in a conveying direction of the recording material; 2. The inkjet recording apparatus according to claim 1,

3. the reflector does not interfere with the viewing angle of the temperature sensing element; 3. The inkjet recording apparatus according to claim 2,

4. The temperature sensing member is located outside the reflector.

4. The inkjet recording apparatus according to claim 3,

5. The notch is formed at the center in the width direction of the first belt.

5. The inkjet recording apparatus according to claim 4,

Images