JP2017228525A - Heater and heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of simplifying the configuration of a heater.SOLUTION: A heater 32 includes resistive members 60 and first pole-side electrodes 601-607. The plurality of resistive members are arranged in a first direction. The first pole-side electrodes are connected to one ends 611, 621 of the resistive members in a second direction perpendicular to the first direction, divide the plurality of resistive members into the plurality of blocks, and cause the plurality of resistive members to generate heat on a block-by-block basis. The first pole-side electrodes include first pole-side first electrodes 601-607 which are provided in the blocks 71-77 each including the plurality of resistive members arranged successively in the first direction, which extend across the one ends of the resistive members in the first blocks, and which connect to the one ends.SELECTED DRAWING: Figure 3

Description

  The embodiment described in this specification relates to a circuit configuration of a heater.

  In some fixing devices, a heater is pressed against a pressure roller via a belt (for example, Patent Document 1). The belt and the pressure roller rotate together to feed the sheet downstream. The heater heats the sheet via the belt. In the apparatus, the heater includes a plurality of resistance members arranged in a direction orthogonal to the sheet conveying direction. An electrode is individually connected to each resistance member. The apparatus selects a resistance member to be energized according to the size of the sheet to be heated.

Japanese Patent Laying-Open No. 2015-219418

  In this apparatus, electrodes are individually connected to each resistance member, and there is a problem that the configuration of the heater is complicated.

  An object of the embodiment is to provide a technique capable of simplifying the configuration of the heater.

  In general, the heater of the embodiment includes a resistance member and a first pole side electrode. The plurality of resistance members are arranged in the first direction. The first pole-side electrode is connected to one end portion in the second direction orthogonal to the first direction of each resistance member, the plurality of resistance members are divided into a plurality of blocks, and the plurality of resistance members generate heat in units of blocks. Let The first pole-side electrode is provided in a first block including a plurality of resistance members arranged continuously in the first direction, and extends across one end of the resistance member in the first block. The 1st pole side 1st electrode connected with the edge part of this is provided.

  In general, the heating device of the embodiment includes a pressure member, a belt, and a heater. The belt conveys the sheet together with the pressure member and heats the sheet to fix the image on the sheet to the sheet. The heater faces the pressure member across the belt and heats the belt. The heater is connected to a plurality of resistance members arranged in the first direction and one end in a second direction orthogonal to the first direction of each resistance member, the plurality of resistance members are divided into a plurality of blocks, 1st pole side electrode which makes a resistance member heat-generate per block, Comprising: It is provided in the 1st block containing the several resistance member arranged in a line in the 1st direction, and the end of one side of the resistance member in a 1st block A first pole-side electrode including a first pole-side first electrode extending between the parts and connected to each one end.

1 is a diagram illustrating an outline of an image forming apparatus according to an embodiment. 1 is a diagram illustrating a configuration of a fixing device according to an embodiment. FIG. 3 is a diagram illustrating a configuration example of a heat generation mechanism of the fixing device according to the embodiment. FIG. 4 is an enlarged view of the heat generating mechanism shown in FIG. 3 and an example of a temperature distribution. It is a figure which shows the temperature distribution at the time of applying the aspect of embodiment based on numerical conditions, and the temperature distribution for contrast. FIG. 10 is a diagram illustrating a configuration example of another fixing device. It is a top view of a heater.

(First embodiment)
Hereinafter, an image forming apparatus and a fixing apparatus according to an embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment. The image forming apparatus 1 includes a reading unit R, an image forming unit P, and a paper feed cassette unit C. The reading unit R reads a document sheet placed on a document table with a CCD (Charge-Coupled Device) image sensor or the like, and converts an optical signal into digital data. The image forming unit P is a unit that acquires a document image read by the reading unit R or print data from an external personal computer, and forms and fixes a toner image on a sheet.

  The image forming unit R includes a laser scanning unit 200 and photosensitive drums 201Y, 201M, 201C, and 201K. The laser scanning unit 200 includes a polygon mirror 208 and an optical system 241 and is formed on a sheet based on image signals of yellow (Y), magenta (M), cyan (C), and black (K) colors. The image is irradiated on the photosensitive drums 201Y to 201K.

  The photosensitive drums 201Y to 201K hold each color toner supplied from a developing device (not shown) according to the irradiation position. The photosensitive drums 201Y to 201K sequentially transfer the held toner images to the transfer belt 207. The transfer belt 207 is an endless belt, and conveys the toner image to the transfer position T when the roller 213 is driven to rotate.

  The conveyance path 101 conveys the sheets stocked in the sheet feeding cassette unit C in the order of the transfer position T, the fixing device 30, and the discharge tray 211. The sheet stocked in the sheet cassette unit C is conveyed to the transfer position T by the guide of the conveyance path 101, and the transfer belt 15 transfers the toner image to the sheet at the transfer position T.

  The sheet on which the toner image is formed is conveyed to the fixing device 30 according to the guidance of the conveyance path 101. The fixing device 30 heats and melts the toner image to infiltrate and fix the sheet. This prevents the toner image on the sheet from being disturbed by an external force. The conveyance path 101 conveys the sheet on which the toner image is fixed to the discharge tray 211 and discharges the sheet to the outside of the image forming apparatus 1.

  The control unit 801 is a unit that comprehensively controls devices and mechanisms in the image forming apparatus 1 and includes, for example, a central processing unit such as a CPU (Central Processing Unit) and a volatile / nonvolatile storage device. As one embodiment, the central processing unit calculates and executes a program stored in the storage device, thereby controlling the devices and mechanisms in the image forming apparatus 1. A part of the function may be mounted as a circuit.

  Note that the transfer unit 40 includes a unit including a unit for conveying an image to be formed (toner image) to a transfer position T and transferring the image onto a sheet.

  FIG. 2 is a diagram illustrating a configuration example of the fixing device 30 (heating device). The fixing device 30 includes a plate-like heater 32 and an endless belt 34 suspended from a plurality of rollers. The fixing device 30 includes a driving roller 33 that suspends an endless belt 34 and rotates the endless belt 34 in a predetermined direction. The fixing device 30 includes a tension roller 35 that suspends the endless belt 34 and applies tension. The fixing device 30 includes a pressure roller 31 (pressure member) having an elastic layer formed on the surface thereof. The heater 32 is in contact with the inner surface of the endless belt 34 on the heat generating portion side and presses in the direction of the pressure roller 31. As a result, the sheet 105 on which the toner image is placed is sandwiched between the contact portion (nip portion) formed by the pressure roller 31 and heated and pressed. That is, the endless belt 34 conveys the sheet with the pressure roller 31 while heating the sheet, and heats the sheet to fix the image on the sheet to the sheet. The heater 32 faces the pressure roller 31 with the endless belt 34 interposed therebetween, and heats the endless belt 34.

  In the heater 32, a heating resistance layer (a heating resistance member 60 described later) is laminated on a ceramic substrate, and a protective layer of a heat resistant member is further laminated. The protective layer is provided to prevent the ceramic substrate and the heating resistance layer from coming into contact with the endless belt 34. Thereby, wear of the endless belt 34 is suppressed.

In this example, the ceramic substrate of the heater 32 has a thickness of 1 to 2 mm, the protective layer is made of Sio ₂ , and the thickness is 60 to 80 μm. The endless belt 34 includes, in order from the side in contact with the heater 32, a base layer (Ni / SUS / PI: thickness 60 to 100 μm), an elastic layer (Si rubber: thickness 100 to 300 μm), and a release layer (PFA: thickness). 15 to 50 μm). The numerical values and materials of each thickness are examples.

  The endless belt 34 may use the rotation of the pressure roller 31 as a belt power source.

FIG. 3 illustrates the heat generating mechanism 50.
Hereinafter, the direction that is the sheet conveyance direction and also the short direction of the heater 32 (the ceramic substrate) is defined as the Z-axis direction (second direction). A direction that is the width direction of the sheet and that is also the longitudinal direction of the heater 32 is defined as a Y-axis direction (first direction). The Y-axis direction is orthogonal to the Z-axis direction. The direction toward the pressure roller 31 and also the vertical direction of the heater 32 is defined as the X-axis direction. The X-axis direction is orthogonal to the Z-axis direction and the Y-axis direction.

  The heater 32 includes a heat generating mechanism 50 that generates heat from the heater 32. The heat generating mechanism 50 includes resistance members 61 and 62, a plurality of electrodes 601 to 607, and an electrode 610. Further, the heat generating mechanism 50 includes a plurality of switching elements 701 to 707, a power source 65, and a wiring 66. The plurality of switching elements 701 to 707 are referred to as a switch unit 700.

  The resistance members 61 and 62 face the surface of the sheet 105 being conveyed. A plurality of resistance members 61 and 62 are arranged in the Y-axis direction. The Y-axis direction is orthogonal to the sheet conveyance direction. Each of the resistance members 61 and 62 has one end connected to the electrode 610 (second pole side electrode) and the other end connected to any of the electrodes 601 to 607 (first pole side electrode).

  The electrode 610 and the electrodes 601 to 607 are formed of an aluminum layer. The electrode 610, which is one electrode, is integrally formed, but the other electrode is divided into electrodes 601 to 607 as shown in the figure. This division of the electrodes 601 to 607 is referred to as a block (blocks 71 to 77) herein. Moreover, in this embodiment, the resistance member 61 is installed in the both ends in each block of the blocks 71-77, and the resistance member 62 is installed inside the block. The length (width length) of the resistance member 61 in the Y-axis direction is longer than the length (width length) of the resistance member 62 in the Y-axis direction, and the area thereof is also large. The reason for this will be described later.

  The electrodes 601 to 607 are connected to the switching elements 701 to 707, respectively. Due to ON / OFF of the switching elements 701 to 707, the resistance members 61 and 62 in the block energize the power supply 65 and generate heat for each of the blocks 71 to 77.

  The positions of the blocks 71 to 77 and the length in the Y-axis direction are defined based on the standard size of the sheet. When the sheet 105 to be conveyed is a small size, heat generation at a portion that does not pass through the sheet is essentially unnecessary. Therefore, in this embodiment, ON / OFF control is performed for each of the blocks 71 to 77 in accordance with the sheet size to be conveyed. For example, when heating a small sheet of A5 size, the block 74 is turned on, and the others are turned off. In the case of the A4 size, for example, the blocks 73, 74, and 75 are turned on, and the other blocks 71, 72, 76, and 77 are turned off. In the case of A3 size, for example, all the blocks are ON. This energization control is performed by the switching elements 701 to 707 performing ON / OFF operations according to the control of the control unit 801. In this way, unnecessary heat generation can be suppressed by controlling which of the blocks the resistance member is energized according to the sheet size.

  In the present embodiment, the blocks are energized differently from each other, while the resistance members 61 and 62 in the block are energized collectively.

  As described above, the electrodes 601 to 607 (first pole side electrodes) are connected to one pole of the power supply 65. The electrodes 601 to 607 are connected to one end portions 611 and 621 in the Z-axis direction of the respective resistance members 61 and 62, and the plurality of resistance members 61 and 62 are divided into a plurality of blocks 71 to 77. The electrodes 601 to 607 cause the plurality of resistance members 61 and 62 to generate heat in units of blocks.

  In the present embodiment, each of the electrodes 601 to 607 is a first pole-side first electrode provided in blocks 71 to 77 (first block) each including a plurality of resistance members 61 and 62 continuously arranged in the Y-axis direction. It is. The electrodes 601 to 607 which are first electrodes on the first pole side extend between one end portions 611 and 621 of the resistance members 61 and 62 in the blocks 71 to 77 (first block), and each one end portion. 611 and 621 are connected.

  On the other hand, the electrode 610 is a second pole-side electrode extending between the other end portions 612 and 622 of the resistance members 61 and 62 in the plurality of blocks 71 to 77 (all blocks) continuously arranged in the Y-axis direction. It is. The electrode 610 that is the second pole side electrode is connected to the other ends 612 and 622 and is connected to the other pole of the power supply 65.

  The upper part of FIG. 4 is an enlarged view of the vicinity of the blocks 71 and 72, and the lower part is a diagram showing an outline of the temperature distribution. The vertical axis of the temperature distribution diagram indicates the temperature transmitted to the endless belt 34, and the horizontal axis indicates the distance from the end of the heating resistance member 60.

  As shown in the upper part of FIG. 4 and FIG. 3 described above, the resistance member 61 is longer in the Y-axis direction (width direction) than the resistance member 62 and is disposed at both ends of each block in the Y-axis direction. ing. Further, the gap L1 between the resistance member 62 and the resistance member 62 in the block (or between the resistance member 61 and the resistance member 62 in the block) is set to 1 mm or less in this embodiment. The temperature at the gap position is lower than the temperature at the position of the resistance member as shown in the lower part of FIG. As the gap L1 becomes larger (longer), this tendency becomes more prominent, and the temperature difference on the temperature distribution diagram becomes larger. By setting the length of the gap L1 within 1 mm as in the present embodiment, the heat generation unevenness is within the allowable range. The length of the gap L1 may be changed according to the size and material of the resistance member.

  In this embodiment, the gap L2 between the blocks 71 to 77 (between the resistance member 61 and the resistance member 61) is longer than the gap L1 in the blocks 71 to 77. In other words, the gap L2 between the blocks 71 to 77 is larger than the gap L1 between the resistance members 61 and 62 in the blocks 71 to 77. This is because a certain distance or more is necessary to prevent leakage between the blocks 71 to 77. In this embodiment, the length of the gap L2 is about 1.5 mm (in the case of 100V). The length of the gap L2 may also be changed according to the size, material, and voltage value of the resistance member.

  Thus, since the gap L2 becomes longer, as shown in the lower part of FIG. 4, the temperature at the position of the inter-block gap L2 with the gap length L2 is the position at the position of the intra-block gap L1 (gap length = L1). The temperature is lower than the temperature (indicated by a solid line on the temperature distribution diagram). In order to suppress this temperature drop, in the embodiment, the width of the resistance member 61 located at both ends of each of the blocks 71 to 77 is made longer than the width of the resistance member 62, and the area is secured wider than the resistance member 62. . By securing the area, the temperature of the resistance member 61 becomes higher than that of the resistance member 62 (indicated by a solid line in the temperature distribution diagram). That is, in the resistance members 61 and 62 in the blocks 71 to 77, the heat generation amounts of the resistance members 61 located at both ends in the Y-axis direction are larger than the heat generation amounts of the other resistance members 62.

  Thus, although the heat generation amount of the resistance member 61 is increased, the heat generated in the resistance member 61 moves from the high temperature side to the low temperature side due to heat conduction. That is, heat moves to the position of the inter-block gap L2 (gap length = L2) adjacent to the resistance member 61. Thereby, the temperature of the resistance member 61 falls, and the temperature in the inter-block gap L2 rises. In the present embodiment, in the temperature distribution diagram shown in the lower part of FIG. 4, the actual temperature is not a solid line but a broken line. Thereby, it can suppress that a temperature difference becomes remarkable and can maintain the uniformity of heating temperature.

  FIG. 5 is a diagram showing a temperature distribution when the intra-block gap L1 is 0.1 mm and the inter-block gap L2 is 1.5 mm. The broken line is the temperature distribution when the width of the resistance member 61 at the end of the blocks 71 to 77 is doubled and the area is widened. The solid lines use the resistance members 61 and 62 having the same width (same area). It is the temperature distribution when there is. The horizontal axis indicates the distance in the Y-axis direction with the center of the heater 32 in the Y-axis direction as the reference zero.

  As shown in FIG. 5, in the temperature distribution of the solid line, the temperature gradually increases from −150 to −50 on the horizontal axis, and reaches a specified temperature (about 150 ° C. in this example) at the center. Further, the temperature gradually decreases from 50 to 150 on the horizontal axis. On the other hand, in the temperature distribution indicated by the broken line, the temperature rapidly rises around −150 to −130 to reach the specified temperature, and suddenly falls around 130 to 150 to become a low temperature. That is, the broken-line temperature distribution means that there are more parts that are at the specified temperature. This is because heat conduction is efficiently performed between the blocks 71 to 77 by increasing the width of the inter-block gap L2.

  Each of the blocks 71 to 77 is configured to have a plurality of resistance members 61 and 62, but may be configured to have only one resistance member 61 and 62. That is, the heating resistance member 60 may be divided only in block units and may be configured as one object in the blocks 71 to 77.

  An aluminum material may be used as the electrode material.

(Second Embodiment)
In the second embodiment, an example in which the configuration of the fixing device is changed from the first embodiment will be described. FIG. 6 is a diagram illustrating a configuration example of the fixing device 30A.

  The film guide 36 has a semi-cylindrical shape, and houses the heater 32 in a recess 361 on the outer peripheral surface.

  The fixing film 34A (belt) is an endless rotating belt. The fixing film 34 </ b> A is fitted on the outer peripheral surface of the film guide 36. The fixing film 34 </ b> A is sandwiched between the film guide 36 and the pressure roller 31 and is driven by the rotation of the pressure roller 31.

  The heater 32 is in contact with the fixing film 34A and heats the fixing film 34A.

  The sheet 105 on which the toner image is formed is conveyed between the fixing film 34 </ b> A and the pressure roller 31. The fixing film 34A heats the sheet and fixes the toner image on the sheet to the sheet.

  The aspects of the heater 32 and the heat generation mechanism 50 shown in FIGS. 3 and 4 can be applied to the fixing device 30A of the second embodiment.

(Third embodiment)
FIG. 7 is a plan view of the heater 32 showing the block 74B.
In the first to third embodiments, any one of the blocks 71 to 77 includes blocks 71 to 77 including a plurality of resistance members 61 and 62 that are continuously arranged in the Y-axis direction (first Block).

  In the third embodiment, one block 74 </ b> B includes only one resistance member 63. The electrodes 601 to 603, 604B, and 605 to 607 are first pole-side electrodes that are connected to one pole of the power supply 65 and cause the plurality of resistance members 61 to 63 to generate heat in units of blocks. The electrode 604 </ b> B is a first pole-side second electrode that is provided in a block 74 </ b> B (second block) including the single resistance member 63 and is connected to one end 631 in the Z-axis direction of the resistance member 63. Other configurations of the third embodiment are the same as those of the first embodiment.

  In the first to third embodiments, the blocks 74 and 74 </ b> B that are turned on when the smallest size sheet is heated are arranged at the center of the blocks 71 to 77 in the Y-axis direction. However, the blocks 74 and 74B that are turned on when the smallest size sheet is heated may be disposed at the ends of the blocks 71 to 77 in the Y-axis direction.

  As described in detail above, in the embodiment, unnecessary heat generation can be suppressed and heat generation unevenness can be suppressed. In the embodiment, since the resistance members 61 and 62 separated by the blocks by the electrodes 601 to 607 (first electrode side first electrode) are energized simultaneously in units of blocks, the resistance members in the same blocks 71 to 77 are used. Similarly, the temperatures of 61 and 62 rise. Therefore, for example, in this embodiment, the temperature difference between the resistance members 61 and 62 is less likely to occur than in the configuration in which the resistance members 61 and 62 are energized instead of in units of blocks. Therefore, the occurrence of temperature unevenness in the same blocks 71 to 77 can be suppressed.

  In the above embodiments, the fixing devices 30 and 30A have been described as examples of the heating device. However, the heating device may perform a decoloring process for heating the sheet and decoloring the image on the sheet. In this case, it is assumed that the image is formed of a decoloring color material that decolors when heated. Further, the heating device may be used other than the heat treatment of the sheet. The heating device may be used for a process for uniformly heating and drying a panel or the like.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by the text of the specification. Further, all modifications, various improvements, alternatives and modifications belonging to the equivalent scope of the claims are all within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 30 Fixing apparatus (heating apparatus), 32 Heater, 31 Pressure roller, 34 Endless belt, 33 Driving roller, 35 Tension roller, 40 Transfer part, 50 Heat generating mechanism, 60 Heat generating resistance member (heat generating resistance part) , 61, 62 Resistance member, 65 Power source, 66 Wiring, 71-77 block (first block), 74B block (second block), 601-607 Electrode (first pole side electrode: first pole side first electrode) , 604B electrode (first pole side second electrode), 610 electrode (second pole side electrode), 611, 621, 631 end (one end in the second direction), 612, 622, 632 end ( The other end in the second direction), 700 switch unit, 701 to 707 switching element, 801 control unit, C paper feed cassette unit, R reading unit, P image forming unit , Y first direction, Z second direction.

Claims (5)

A plurality of resistance members arranged in a first direction;
A first end of each resistance member connected to one end in a second direction orthogonal to the first direction, the plurality of resistance members divided into a plurality of blocks, and the plurality of resistance members generating heat in units of blocks. A pole-side electrode, provided in a first block including a plurality of the resistance members arranged continuously in the first direction, and extending between the one end portions of the resistance members in the first block. A first pole-side electrode comprising a first pole-side first electrode extending and connected to the respective one end;
A heater comprising: The heater according to claim 1, wherein
In the resistance member in the first block, the heat generation amount of the resistance members located at both ends in the first direction is larger than the heat generation amount of the other resistance members. The heater according to claim 1 or 2,
A first portion that is provided between the plurality of blocks, extends between the other end portions of the resistance members in the second direction in the second direction, and is connected to the other end portions; A bipolar electrode is provided. The heater according to any one of claims 1 to 3,
The gap between the blocks is larger than the gap between the resistance members in the first block. A pressure member;
A belt that sandwiches and conveys the sheet together with the pressure member, heats the sheet, and fixes the image on the sheet to the sheet;
A heater that opposes the pressure member across the belt and heats the belt;
A plurality of resistance members arranged in a first direction;
A first end of each resistance member connected to one end in a second direction orthogonal to the first direction, the plurality of resistance members divided into a plurality of blocks, and the plurality of resistance members generating heat in units of blocks. A pole-side electrode, provided in a first block including a plurality of the resistance members arranged continuously in the first direction, and extending between the one end portions of the resistance members in the first block. A first pole-side electrode comprising a first pole-side first electrode extending and connected to the respective one end;
A heating device comprising: