JP2017228521A - Heater and heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater and a heating device which heat a rotating body by using a plurality of heat generating members to reduce temperature unevenness on the rotating body to achieve temperature equalization.SOLUTION: The heater includes: a heat-resistant insulating base material; a plurality of heat generating members arranged on a first surface of the insulating base material; and a heat radiation body disposed on a surface different from the first surface of the insulating base material to supplement a gap portion between the plurality of heat generating members and radiating actively or passively held heat.SELECTED DRAWING: Figure 10

Description

  The present embodiment relates to a heater and a heating device.

  Conventionally, in a fixing device mounted on an image forming apparatus, it has been studied to heat a toner image on a sheet by dividing and arranging a plurality of heating elements in a direction orthogonal to the sheet conveyance direction. In this case, a gap is required between adjacent heating elements. However, this gap cannot generate heat. For this reason, there exists a subject that temperature falls in a gap | interval part and temperature unevenness arises.

JP 2015-28531 A

  The problem to be solved by the present invention is to provide a heater and a heating device that reduce temperature unevenness and achieve uniform temperature when heating is performed using a plurality of heating members.

  The heater of the present embodiment includes a heat-resistant insulating base material, a plurality of heat generating members arranged on the first surface of the insulating base material, and a gap portion between the plurality of heat generating members. A heat radiator disposed on a surface different from the first surface of the insulating substrate and radiating heat held actively or passively.

1 is a configuration diagram illustrating an image forming apparatus including a fixing device according to a first embodiment. FIG. 2 is a configuration diagram illustrating an enlarged part of an image forming unit according to the first embodiment. 1 is a configuration diagram illustrating an example of a fixing device according to a first embodiment. FIG. 2 is a block diagram showing a control system of the MFP in the first embodiment. The top view which shows the basic composition of the heating member in 1st Embodiment. Explanatory drawing which shows the connection state of the heat generating member group of the heating member of FIG. 5, and a drive circuit. FIG. 7 is an explanatory diagram showing a positional relationship between the heat generating member group of FIG. 6 and a print area of a sheet. The figure which shows another example of arrangement | positioning of the heat generating member group in 1st Embodiment. The figure which shows another example of arrangement | positioning of the heat generating member group in 1st Embodiment. The perspective view, sectional drawing, and schematic sectional drawing which show the structure of the heating member in 1st Embodiment. The perspective view, sectional drawing, and schematic sectional drawing which show the other structure of the heating member in 1st Embodiment. FIG. 6 is a schematic cross-sectional view showing still another configuration of the heating member in the first embodiment. The perspective view, sectional drawing, and schematic sectional drawing which show the structure of the heating member in 2nd Embodiment. The perspective view, sectional drawing, and schematic sectional drawing which show the other structure of the heating member in 2nd Embodiment. The schematic sectional drawing which shows the further another structure of the heating member in 2nd Embodiment. FIG. 9 is a configuration diagram showing a modification of the fixing device according to the embodiment. 6 is a flowchart illustrating a control operation of the MFP according to the embodiment.

(First embodiment)
FIG. 1 is a configuration diagram illustrating an image forming apparatus including a heater and a fixing device (heating device) according to the first embodiment. In FIG. 1, an image forming apparatus 10 is, for example, an MFP (Multi-Function Peripherals), a printer, a copier, or the like, which is a multifunction peripheral. In the following description, an MFP will be described as an example.

  A transparent glass platen 12 is provided above the main body 11 of the MFP 10, and an automatic document feeder (ADF) 13 is provided on the platen 12 so as to be freely opened and closed. An operation unit 14 is provided on the upper portion of the main body 11. The operation unit 14 includes an operation panel having various keys and a touch panel display.

  A scanner unit 15 serving as a reading device is provided below the ADF 13 in the main body 11. The scanner unit 15 generates image data by reading a document sent by the ADF 13 or a document placed on a document table, and includes a contact image sensor 16 (hereinafter simply referred to as an image sensor). The image sensor 16 is arranged in the main scanning direction (the depth direction in FIG. 1).

  When reading the image of the document placed on the document table 12, the image sensor 16 reads the document image line by line while moving along the document table 12. This is executed over the entire document size, and one page of document is read. Further, when reading an image of a document sent by the ADF 13, the image sensor 16 is in a fixed position (position shown in the drawing).

  Further, a printer unit 17 is provided at the center of the main body 11. The printer unit 17 processes image data read by the scanner unit 15 or image data created by a personal computer or the like, and forms an image on a recording medium (for example, paper). In addition, a plurality of paper feed cassettes 18 for storing various sizes of paper are provided at the bottom of the main body 11. As a recording medium for forming an image, there is an OHP sheet or the like in addition to the paper. In the following description, an example of forming an image on the paper will be described.

  The printer unit 17 includes a photosensitive drum and a scanning head 19 including an LED as an exposure device. The printer unit 17 scans the photosensitive member with a light beam from the scanning head 19 to generate an image. The printer unit 17 is a tandem color laser printer, for example, and includes image forming units 20Y, 20M, 20C, and 20K for each color of yellow (Y), magenta (M), cyan (C), and black (K).

  The image forming units 20Y, 20M, 20C, and 20K are arranged below the intermediate transfer belt 21 in parallel from upstream to downstream. The scanning head 19 also has a plurality of scanning heads 19Y, 19M, 19C, and 19K corresponding to the image forming units 20Y, 20M, 20C, and 20K.

  FIG. 2 is an enlarged configuration diagram illustrating the image forming unit 20K among the image forming units 20Y, 20M, 20C, and 20K. In the following description, since the image forming units 20Y, 20M, 20C, and 20K have the same configuration, the image forming unit 20K will be described as an example.

  The image forming unit 20K includes a photosensitive drum 22K that is an image carrier. A charging charger 23K, a developing device 24K, a primary transfer roller (transfer device) 25K, a cleaner 26K, a blade 27K, and the like are arranged around the photosensitive drum 22K along the rotation direction t. The exposure position of the photosensitive drum 22K is irradiated with light from the scanning head 19K to form an electrostatic latent image on the photosensitive drum 22K.

  The charging charger 23K of the image forming unit 20K uniformly charges the surface of the photosensitive drum 22K. The developing device 24K supplies a two-component developer including black toner and a carrier to the photosensitive drum 22K by a developing roller 24a to which a developing bias is applied, and develops the electrostatic latent image. The cleaner 26K removes residual toner on the surface of the photosensitive drum 22K using the blade 27K.

  As shown in FIG. 1, a toner cartridge 28 that supplies toner to the developing devices 24Y to 24K is provided above the image forming units 20Y to 20K. The toner cartridge 28 includes toner cartridges 28Y, 28M, 28C, and 28K for each color of yellow (Y), magenta (M), cyan (C), and black (K).

  The intermediate transfer belt 21 is stretched around a driving roller 31 and a driven roller 32 and moves cyclically. The intermediate transfer belt 21 is in contact with the photosensitive drums 22Y to 22K. A primary transfer voltage is applied to the position of the intermediate transfer belt 21 facing the photosensitive drum 22K by the primary transfer roller 25K, and the toner image on the photosensitive drum 22K is primarily transferred to the intermediate transfer belt 21.

  A secondary transfer roller 33 is disposed opposite to the drive roller 31 that stretches the intermediate transfer belt 21. When the paper P passes between the driving roller 31 and the secondary transfer roller 33, a secondary transfer voltage is applied to the paper P by the secondary transfer roller 33. Then, the toner image on the intermediate transfer belt 21 is secondarily transferred to the paper P. A belt cleaner 34 is provided near the driven roller 32 of the intermediate transfer belt 21.

  Further, as shown in FIG. 1, a sheet feed roller 35 that conveys the sheet P taken out from the sheet feed cassette 18 is provided between the sheet feed cassette 18 and the secondary transfer roller 33. Further, a fixing device 36 that is a heating device is provided downstream of the secondary transfer roller 33. Further, a conveyance roller 37 is provided downstream of the fixing device 36. The conveyance roller 37 discharges the paper P to the paper discharge unit 38. Further, a reverse conveyance path 39 is provided downstream of the fixing device 36. The reverse conveyance path 39 reverses the paper P and guides it in the direction of the secondary transfer roller 33, and is used when performing duplex printing.

  FIGS. 1 and 2 show an example of the embodiment. The structure of the image forming apparatus other than the fixing device 36 is not limited to the example shown in FIGS. The structure of the device can be used.

  FIG. 3 is a configuration diagram showing the fixing device 36 which is a heating device. The fixing device 36 includes a fixing belt 41 that is a rotating body, a press roller 42 (pressure roller), belt conveyance rollers 43 and 44, and a tension roller 45. The fixing belt 41 is an endless belt on which an elastic layer is formed. The fixing belt 41 is rotatably stretched by belt conveying rollers 43 and 44 and a tension roller 45, and the fixing belt 41 is wound around a part of the press roller 42. The tension roller 45 applies a predetermined tension to the fixing belt 41.

  A plate-like heating member 46 (heater) is provided between the belt conveying rollers 43 and 44 inside the rotating body (fixing belt 41). The heating member 46 contacts the inside of the fixing belt 41 and is pressed in the direction of the press roller 42 to form a fixing nip having a predetermined width between the fixing belt 41 and the press roller 42.

  When the paper P passes through the fixing nip, the toner image on the paper P is fixed to the paper P with heat and pressure. The press roller 42 is rotated by a driving force transmitted by a motor (the direction of rotation is indicated by an arrow t in FIG. 3). The fixing belt 41, the belt conveying rollers 43 and 44, and the tension roller 45 are driven by the rotation of the press roller 42 (the rotation direction is indicated by an arrow s in FIG. 3).

  The fixing belt 41, which is a rotating body, has, for example, a silicon rubber layer (elastic layer) having a thickness of 200 um formed on a SUS base material having a thickness of 50 um or polyimide, which is a heat-resistant resin having 70 um, and the outermost periphery is made of PFA or the like. It is covered with a surface protective layer. In the press roller 42, for example, a silicon sponge layer having a thickness of 5 mm is formed on the surface of an iron rod having a diameter of 10 mm, and the outermost periphery is covered with a surface protective layer such as PFA. The detailed configuration of the heating member 46 will be described later.

  FIG. 4 is a block diagram illustrating a configuration example of a control system of the MFP 10 according to the first embodiment. The control system includes, for example, a CPU 100 that controls the entire MFP 10, a bus line 110, a read only memory (ROM) 120, a random access memory (RAM) 121, an interface (I / F) 122, a scanner unit 15, and an input / output control circuit 123. A paper feed / conveyance control circuit 130, an image formation control circuit 140, and a fixing control circuit 150. The CPU 100 and each circuit are connected via a bus line 110.

  The CPU 100 controls the entire MFP 10 and realizes a processing function for image formation by executing a program stored in the ROM 120 or the RAM 121. The ROM 120 stores a control program and control data for performing basic operations of the image forming process. The RAM 121 is a working memory.

  The ROM 120 (or RAM 121) stores, for example, control programs for the image forming unit 20 and the fixing device 36, and various control data used by the control programs. As a specific example of the control data in the present embodiment, there is a correspondence relationship between the size of the print area of the paper (width in the main scanning direction) and the heat generating member to be energized.

  The fixing temperature control program of the fixing device 36 includes determination logic for determining the size of the image forming region on the paper on which the toner image is formed, and the image forming region passes before the paper is conveyed into the fixing device 36. And a heating control logic for controlling the heating in the heating member 46 by selecting a switching element of the heat generating member corresponding to the position and energizing it.

  The I / F 122 performs communication with various apparatuses such as a user terminal and a facsimile. The input / output control circuit 123 controls the operation panel 14a and the display 14b. When the operator operates the operation panel 14a, for example, the paper size, the number of copies of the original, and the like can be designated.

  The paper feed / conveyance control circuit 130 controls a group of motors 131 that drive the paper feed roller 35 or the conveyance roller 37 in the conveyance path. The paper feed / conveyance control circuit 130 controls the motor group 131 and the like in consideration of detection results of various sensors 132 in the vicinity of the paper feed cassette 18 or on the conveyance path based on a control signal from the CPU 100.

  The image formation control circuit 140 controls the photosensitive drum 22, the charger 23, the exposure device (scanning head) 19, the developing device 24, and the transfer device 25 based on a control signal from the CPU 100.

  The fixing control circuit 150 controls the drive motor 151 that rotates the press roller 42 of the fixing device 36 based on a control signal from the CPU 100. In addition, energization of a heating member (described later) of the heating member 46 is controlled. The fixing control circuit 150 receives temperature information of the heating member 46 from a temperature detection member 152 such as a thermistor, and controls the temperature of the heating member 46. In the present embodiment, the control program and control data of the fixing device 36 are stored in the storage device of the MFP 10 and executed by the CPU 100. However, the arithmetic processing device and the storage device are separately provided exclusively for the fixing device 36. May be.

  FIG. 5 is a plan view showing a basic configuration of the heating member 46 (heater) in the first embodiment. The heating member 46 is composed of a heat generating member group. As shown in FIG. 5, the heating member 46 has a plurality of heat generating members 51 with a predetermined width arranged in a longitudinal direction (horizontal direction in the drawing) on a heat-resistant insulating base material such as a ceramic substrate 50.

The heating member 51 is formed, for example, directly on one surface of the ceramic substrate 50 or by laminating a glaze layer and a heating resistor layer. The heating resistor layer constitutes the heating member 51 as described above, and is formed of a known material such as TaSiO ₂ and divided into a predetermined length and a predetermined number in the longitudinal direction of the heating member 46. . Details of the arrangement of the heating members 51 will be described later. Electrodes 52a and 52b are formed at both ends of the heat generating member 51 in the paper conveyance direction (the vertical direction in the figure).

  In the following description, the paper conveyance direction will be described as the Y direction. The longitudinal direction of the heating member 46 is a direction orthogonal to the paper transport direction, and corresponds to the main scanning direction when an image is formed on the paper, and will be described as the X direction in the following description.

  FIG. 6 is an explanatory diagram showing a connection state of the heat generating member group and its drive circuit in the heating member 46 of FIG. In FIG. 6, energization of the plurality of heat generating members 51 is individually controlled by a plurality of driving ICs (integrated circuits) 531, 532, 533, and 534. That is, each electrode 52 a of the heat generating member 51 is connected to one end of the drive source 54 via the drive ICs 531, 532, 533, and 534, and each electrode 52 b is connected to the other end of the drive source 54.

  As specific examples of the drive ICs 531 to 534, switching elements made of FETs, triax, switching ICs, and the like can be used. When the switches of the drive ICs 531 to 534 are turned on, the heat generating member 51 is energized from the drive source 54. Therefore, the drive ICs 531 to 534 constitute a switching unit of the heat generating member 51. As the drive source 54, for example, an AC power supply (AC) or a DC power supply (DC) can be used. In the following description, the drive ICs 531 to 534 may be collectively referred to as the drive IC 53.

  Further, a thermostat 55 may be connected to the drive source 54 in series. The thermostat 55 is turned off when the temperature of the heating member 46 reaches a preset temperature (dangerous temperature), the connection between the drive source 54 and the heat generating member 51 is cut off, and the heating member 46 is abnormally heated. prevent.

  FIG. 7 is a diagram for explaining the positional relationship between the heat generating member group of FIG. 6 and the print area of the paper. Here, it is assumed that the paper P is conveyed in the direction of the arrow Y. FIG. 7 shows a state in which the switch of the driving IC 53 connected to the heat generating member 51 located at a position corresponding to the printing area of the paper (the width W of the image forming area) is selectively turned on to be energized and heated. ing. That is, only the print area of the paper P is heated intensively.

  Further, before the paper P is conveyed into the fixing device 36, the size of the print area of the paper P is determined. As a method of determining the print area of the paper P, there is a method of using an analysis result of image data read by the scanner unit 15 or image data created by a personal computer or the like. Further, there are a method for determining a print area based on print format information such as a margin setting for the paper P, and a method for determining a print area based on a detection result of an optical sensor.

  FIG. 8 is a diagram illustrating another arrangement example of the heat generating member group in the first embodiment. There are various sizes of the paper P conveyed to the fixing device 36. For example, A5 size (148 mm), A4 size (210 mm), B4 size (257 mm), and A4 horizontal size (297 mm) are used relatively frequently.

  Therefore, in FIG. 8, the heat generating members 51 having a plurality of types of widths are arranged in the X direction corresponding to the paper size (here, the four types of sizes described above). The heat generating member group is energized with a margin of about 5% in the heating area in consideration of the conveyance accuracy of the conveyed sheet, the occurrence of skew, or the escape of heat to the non-heated portion.

  For example, the first heat generating member 511 is provided in the central portion in the X direction corresponding to the width (148 mm) of the A5 size which is the minimum size among the above four types of sizes. The second heat generating members 512 and 513 are provided outside the heat generating member 511 in the X direction corresponding to the next largest A4 size width (210 mm). Similarly, the third heat generating members 514 and 515 are provided outside the second heat generating members 512 and 513 corresponding to the width (257 mm) of the next largest B4 size. The fourth heat generating members 516 and 517 are provided outside the third heat generating members 514 and 515 in correspondence with the larger width (297 mm) of the A4 horizontal size.

  The electrodes 52 a of the heat generating members (511 to 517) are connected to one end of the drive source 54 via the drive ICs 531 to 537, and the electrodes 52 b are connected to the other end of the drive source 54. In addition, the number and the width | variety of each of the heat generating members (511-517) shown in FIG. 8 are mentioned as an example, and are not limited to this.

  Thus, in FIG. 8, when the paper P is transported along the central portion of the transport path and the paper P of the minimum size (A5) is transported, the drive connected to the first heat generating member 511 in the central portion. Only the IC 531 is switched on. Further, as the size of the paper P increases, the driving ICs (532-537) connected to the second to fourth heating members (512-517) are sequentially switched on.

  FIG. 9 is a diagram illustrating still another arrangement example of the heat generating member group in the first embodiment. FIG. 9 shows an example in which the paper P is transported along one end (for example, the left side) of the transport path. Similar to FIG. 8, a plurality of types of widths corresponding to four types of paper sizes are shown. The heating members 51 are arranged in the X direction.

  For example, the first heat generating member 511 is provided on the leftmost side in the X direction corresponding to the width of the A5 size which is the minimum size among the four sizes. Further, a second heat generating member 512 is provided on the right side of the heat generating member 511 corresponding to the next largest A4 size width. Similarly, a third heat generating member 513 is provided on the right side of the second heat generating member 512 corresponding to the width of the next largest B4 size. Further, a fourth heat generating member 514 is provided on the right side of the third heat generating member 513 corresponding to the width of the larger A4 horizontal size.

  And the electrode 52a of each heat generating member (511-514) is connected to one end of the drive source 54 via drive IC531-534, and the electrode 52b of each heat generating member (511-514) is the other end of the drive source 54. It is connected to the. In addition, the number and the width | variety of each of the heat generating members (511-514) shown in FIG. 9 are mentioned as an example, and are not limited to this.

  Thus, in FIG. 9, when the paper P of the minimum size (A5) is conveyed, only the driving IC 531 connected to the leftmost first heat generating member 511 is switched on. Further, as the size of the paper P increases, the drive ICs (532-534) connected to the second to fourth heat generating members (512-514) are sequentially switched on.

  In this embodiment, a line sensor 40 (see FIG. 1) is arranged in the sheet passing area so that the size and position of the passing sheet can be determined in real time. Alternatively, the paper size may be determined from the image data at the start of the printing operation or the information in the paper feed cassette 18 in which the paper in the MFP 10 is stored.

  By the way, in the heating member 46 of FIGS. 5 and 6, a gap 56 exists between the adjacent heating members 51. Similarly, in the heating member 46 of FIGS. 8 and 9, there is a gap 56 between adjacent heating members. Since the gap 56 cannot generate heat, a temperature drop occurs in the gap, and uneven heat generation occurs in a direction perpendicular to the paper transport direction Y. The unevenness of heat generation affects the fixing quality. In particular, in the case of color printing, there is a possibility that a difference in color development and gloss may occur.

  Therefore, in the heater and the fixing device according to the first embodiment, the ceramic substrate has, for example, a multilayer structure, and a plurality of heat generating members 51 are arranged in the X direction on the first surface (on the first layer) of the ceramic substrate. In addition, a heat radiator that actively or passively generates heat (radiates the stored heat) is disposed on the second surface (on the second layer) so as to supplement the gap between the plurality of heat generating members. Yes.

  FIG. 10 is a diagram illustrating a configuration of a heating member 46 (heater) according to an embodiment, and (a) is a perspective view. The heating member 46 in FIG. 10A corresponds to an example in which a plurality of heating members 51 having a certain width are arranged in the X direction, as shown in FIG.

  As shown in FIG. 10A, the ceramic substrate 50 that is a heat-resistant insulating base material has a multilayer structure including a first-layer ceramic substrate 501 and a second-layer ceramic substrate 502. The ceramic substrate 501 of the first layer forms a layer constituting the main body portion in the ceramic substrate 50, that is, a base layer.

A heating resistor layer is laminated directly on the first surface of the ceramic substrate 50 (for example, the first-layer ceramic substrate 501). A heating resistor layer is directly laminated on the second surface of the ceramic substrate 50 (for example, the second-layer ceramic substrate 502). The heat generating resistive layer constitutes the heat generating member 51 and is formed of a known material such as TaSiO ₂ (or the heat generating member 51 is formed by laminating a glaze layer and a heat generating resistive layer on the ceramic substrates 501 and 502. You may). Here, the plurality of heat generating members 51 on the second surface are members for soaking, and constitute a heat radiator that radiates actively held heat.

  The heating members 51 on the first-layer ceramic substrate 501 are arranged in the longitudinal direction (X direction) of the ceramic substrate 501 with a predetermined gap 57 therebetween. The heating members 51 on the second-layer ceramic substrate 502 are also arranged in the longitudinal direction (X direction) of the ceramic substrate 502 with a predetermined gap 57 therebetween.

  However, the heat generating member 51 disposed in the second layer is disposed so as to supplement the gap 57 between the heat generating members 51 in the first layer. That is, the first layer heat generating members 51 and the second layer heat generating members 51 are alternately arranged in the vertical direction. Further, the first layer heat generating member 51 and the second layer heat generating member 51 overlap each other in the X direction.

Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature. Further, a protective layer 503 may be provided on the second-layer ceramic substrate 502. The protective layer 503 is formed of, for example, Si ₃ N ₄ or the like.

 FIG. 10B is a cross-sectional view of the heating member 46 as viewed from the direction of arrow A in FIG. As shown in FIG. 10B, the heat generating member 51 is formed in multiple layers on the ceramic substrates 501 and 502. The method for forming the heat generating member 51 (heat generating resistance layer) is the same as a known method (for example, a method for producing a thermal head), and a masking layer is formed of aluminum on the heat generating resistance layer. Adjacent heating members are insulated. The aluminum layers (electrodes 52a and 52b) are formed in a pattern that exposes the heat generating member 51 in the Y direction.

 A conductor 58 for wiring is connected to the aluminum layers (electrodes 52a and 52b) at both ends of each heating member 51, and the conductor 58 passes through a wiring pattern 59 formed on the ceramic substrates 501 and 502 by screen printing or the like. The wiring patterns 59 are connected to the switching elements of the driving IC 53 by connecting them with hole patterns (through holes filled with silver paste). Therefore, power supply to each heat generating member 51 is performed from the drive source 54 via the wiring pattern 59, the conductor 58, and the switching element of the drive IC 53.

  Further, a protective layer 503 is formed on the top so as to cover all of the heat generating member 51, the aluminum layers (electrodes 52a and 52b), the conductor 58, and the like on the second-layer ceramic substrate 502. When AC or DC is supplied from the drive source 54 to such a heat generating member group, switching elements (triacs, FETs) of the drive IC are switched by a zero cross circuit, and flicker should be taken into consideration.

  FIG. 10C is a schematic cross-sectional view of the heating member 46 as viewed from the Y direction. As can be seen from FIG. 10C, the heating members 51 are arranged on the first-layer ceramic substrate 501 and the second-layer ceramic substrate 502. The heating members 51 of the first layer are arranged in the X direction of the ceramic substrate 501 with a gap 57 having a predetermined width. The second layer heat generating members 51 are arranged with a gap 57 having a predetermined width so as to supplement the gap 57 of the first layer.

  The first layer heat generating members 51 and the second layer heat generating members 51 are alternately arranged in the vertical direction. The first layer heat generating members 51 and the second layer heat generating members 51 are arranged in the X direction. The parts overlap each other. Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature.

  FIG. 10D is a schematic cross-sectional view showing another example of the heating member 46. The heating member 46 in FIG. 10D corresponds to the example in FIG. In FIG. 10D, only the heat generating members 511, 512, 514, and 516 are shown. The heat generating members 511, 513, 515, and 517 are bilaterally symmetric with respect to the arrangement of the heat generating members 511, 512, 514, and 516, and illustration thereof is omitted.

  In the example of FIG. 10D, the heat generating members 516 and 512 on the first-layer ceramic substrate 501 are arranged in the X direction on the ceramic substrate 501 with a gap 57 having a predetermined width. The heating members 514 and 511 on the second-layer ceramic substrate 502 are arranged with a gap 57 having a predetermined width so as to supplement the gap 57 of the first layer.

  The heat generating members (516, 512) of the first layer and the heat generating members (514, 511) of the second layer are alternately arranged in the vertical direction. Further, both end portions in the X direction of the heat generating member of the first layer overlap with both end portions in the X direction of the heat generating member of the second layer. Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature.

  By making the temperature of the heating member 46 uniform, the temperature unevenness of the fixing belt 41 can be reduced and the temperature can be equalized, the toner is uniformly adhered during image formation, the color unevenness is reduced, and the image quality is improved. Can be improved.

  The heating member 46 in FIG. 10D corresponds to the example in FIG. 8, but may be configured to correspond to the example in FIG. That is, the heat generating members 511 and 513 in FIG. 9 may be disposed on the ceramic substrate 501 with the gap 57 therebetween, and the heat generating members 512 and 514 may be disposed on the ceramic substrate 502 with the gap 57 therebetween. Also in this case, both ends in the X direction of the heat generating member of the first layer are arranged so as to overlap with both ends in the X direction of the heat generating member of the second layer.

  The heat generating member on the first surface (first layer) and the heat generating member on the second surface (second layer) are layers far from the surface of the ceramic substrate 50 (position where the heating member 46 contacts the fixing belt 41) ( If the heat generation amount of the heat generating member of the first layer) is set to be large, it is possible to achieve more uniform temperature.

  That is, when the heating member 46 is brought into contact with the fixing belt 41, the first-layer ceramic substrate 501 that forms the base layer of the ceramic substrate 50 is located at a distance away from the fixing belt 41. For this reason, the heat generation amount in the longitudinal direction of the heating member 46 in contact with the fixing belt 41 is increased by making the heat generation amount of the heat generation member of the first layer larger than the heat generation amount of the heat generation member 51 of the second layer close to the fixing belt 41. Becomes substantially uniform, and the fixing belt 41 can be heated at a uniform temperature.

  In order to increase the heat generation amount of the heat generating member in the layer far from the position in contact with the fixing belt 41, a resistance heat generating layer made of a different material may be used. Alternatively, in order to increase the amount of heat generation, it is preferable to form a thick resistance heating layer with the same material. Further, when viewed from the surface of the ceramic substrate 50, the length in the Y direction of the heat generating member of the far layer may be shortened.

  Thus, the heating member 46 is set so that the heat generation amount of the heat generating member on the first surface is different from the heat generation amount of the heat generating member (thermal radiator) on the second surface, and the contact position (nip) with the fixing belt 41 is set. ) So that the heat generation amount of the heat generation member 51 in the far layer (first layer) is larger than the heat generation amount of the heat generation member 51 in the near layer (second layer). Can be achieved.

  FIG. 11 is a diagram illustrating another configuration of the heating member 46 (heater) according to an embodiment. FIG. 11A is a perspective view. In the heating member 46, a plurality of heating members 51 each having a constant width are arranged in the X direction on both surfaces of a single insulating substrate (for example, a ceramic substrate 501). In FIG. 11, the upper surface of the ceramic substrate 501 is referred to as the front surface, and the lower surface is referred to as the back surface.

On the back surface (first surface) and the front surface (second surface) of the ceramic substrate 501, a heating resistance layer is directly laminated, respectively (or the glaze layer and heat generation on the back surface and the front surface of the ceramic substrate 501). A resistive layer may be formed by stacking). The heating resistance layer constitutes the heating member 51 and is formed of a known material such as TaSiO ₂ .

  Further, the heating members 51 formed on the back surface (first surface) of the ceramic substrate 501 are arranged in the longitudinal direction (X direction) with a predetermined gap 57 therebetween. The heating members 51 formed on the surface (second surface) of the ceramic substrate 501 are also arranged in the longitudinal direction (X direction) with a predetermined gap 57 therebetween. However, the heat generating member 51 disposed on the front surface is disposed so as to supplement the gap 57 between the heat generating members 51 on the back surface, and the heat generating member 51 disposed on the back surface and the heat generating member 51 disposed on the front surface are end portions in the X direction. The parts overlap each other.

Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature. Further, the protective layer 503 may be provided on the upper surface side of the ceramic substrate 501 and the protective layer 504 may be provided on the lower surface side. The protective layers 503 and 504 are made of, for example, Si ₃ N ₄ .

 FIG.11 (b) is sectional drawing of the heating member 46 seen from the arrow A direction of Fig.11 (a). As shown in FIG. 11B, the heat generating member 51 is formed on both surfaces of the ceramic substrate 501. The aluminum layers (electrodes 52a and 52b) are formed in a pattern that exposes the heat generating member 51 in the Y direction.

 A wiring conductor 58 is connected to the electrodes 52a and 52b at both ends of each heating member 51. The conductor 58 is connected to a wiring pattern 59 formed on the ceramic substrate 501 by screen printing or the like, and the wiring pattern 59 is connected to a switching element of the driving IC 53.

 In FIG. 11, the details of the wiring pattern 59 are omitted in order to mainly explain the arrangement of the heat generating members 51, but if the width of the ceramic substrate 501 in the Y direction is increased, a space for forming the wiring pattern 59 is secured. be able to. Thus, power is supplied to each heat generating member 51 from the drive source 54 via the wiring pattern 59, the conductor 58, and the switching element of the drive IC 53.

  FIG.11 (c) is the schematic sectional drawing which looked at the heating member 46 from the Y direction. The heating members 51 on the back side of the ceramic substrate 501 are arranged in the X direction with a gap 57 having a predetermined width. Further, the heat generating members 51 on the front side are arranged with a gap 57 having a predetermined width so as to supplement the gap 57 on the back side.

  The heat generating members 51 on the back surface side and the heat generating members 51 on the front surface side are alternately arranged in the vertical direction, and the heat generating members 51 overlap each other in the X direction. Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature.

  FIG. 11D is a schematic cross-sectional view showing another example of the heating member 46. The heating member 46 in FIG. 11D corresponds to the example in FIG. In FIG. 11D, only the heat generating members 511, 512, 514, and 516 are shown. The heat generating members 511, 513, 515, and 517 are bilaterally symmetric with respect to the arrangement of the heat generating members 511, 512, 514, and 516, and illustration thereof is omitted.

  In the example of FIG. 11D, the heating members 516 and 512 are arranged in the X direction with a gap 57 having a predetermined width on the back side of the ceramic substrate 501. Further, on the surface side of the ceramic substrate 501, heating members 514 and 511 are arranged in the X direction with a gap 57 having a predetermined width so as to supplement the gap 57. The heat generating members (516, 512) on the back surface side and the heat generating members (514, 511) on the front surface side are alternately arranged in the vertical direction, and both end portions in the X direction of the heat generating members overlap each other.

  Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature. By making the temperature of the heating member 46 uniform, the temperature unevenness of the fixing belt 41 can be reduced and the temperature can be equalized, and the quality during image formation can be improved.

  The heat generating member on the first surface (back surface) and the heat generating member on the second surface (front surface) are the surfaces (back surface) far from the surface of the ceramic substrate 501 (position where the heating member 46 contacts the fixing belt 41). If the heat generation amount of the heat generating member is set to be large, it is possible to achieve more uniform temperature.

  In addition, although the heating member 46 of FIG.11 (d) respond | corresponds to the example of FIG. 8, it can also be comprised so that it may respond | correspond to the example of FIG. That is, the heating members 511 and 513 of FIG. 9 are arranged on the first surface (for example, the back surface) of the ceramic substrate 501 with the gap 57 therebetween. Further, the heating members 512 and 514 are arranged on the second surface (for example, the surface) with the gap 57 interposed therebetween so as to supplement the gap 57. Also in this case, both end portions in the X direction of the heat generating member on the first surface are arranged so as to overlap both end portions in the X direction of the heat generating member on the second surface.

  FIG. 12 is a schematic cross-sectional view showing another modification of the heating member 46. FIG. 12 is a modification of the arrangement of the first layer heat generating members 51 and the second layer heat generating members 51 in FIG. As shown in FIG. 12A, heating members 51 are arranged on the first-layer and second-layer ceramic substrates 501 and 502. The heating members 51 of the first layer are arranged in the X direction of the ceramic substrate 501 with a gap 57 having a predetermined width. The second layer heat generating members 51 are arranged with a gap 57 having a predetermined width so as to supplement the gap 57 of the first layer.

  The first layer heating members 51 and the second layer heating members 51 are alternately arranged in the vertical direction, but the first layer heating members 51 and the second layer heating members 51 are arranged in the X direction. The end portions coincide with the opposing gap 57 without overlapping. That is, the interval 57 is set to coincide with the width in the X direction of the heat generating member 51 of the first layer and the heat generating member 51 of the second layer.

  Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is arranged in the X direction without any break, and can be controlled to a uniform temperature. As shown in FIG. 10C, the first layer heat generating member 51 and the second layer heat generating member 51 do not overlap, but the first layer gap 57 is supplemented by the second layer heat generating member 51. Therefore, it is possible to suppress the temperature drop at the gap 57 portion.

  FIG. 12B is a further modification of the heating member 46. On the first layer and the second layer ceramic substrates 501, 502, the heating members 51 are arranged in the X direction with a gap 57 of a predetermined width, respectively, and the first layer heating members 51 and the second layer are arranged. The heating members 51 are alternately arranged in the vertical direction.

  However, the first layer heat generating member 51 and the second layer heat generating member 51 do not overlap each other in the X direction, and the interval 57 is the X direction of the first layer and second layer heat generating member 51. It is set slightly larger than the width. Therefore, when the heating member 46 is viewed from directly above in the drawing, the heat generating member 51 is arranged in the X direction with some cuts.

  In the example of FIG. 12 (b), as shown in FIG. 10 (d), the end portions of the heat generating members 51 of the first layer and the second layer do not overlap. Since it supplements with the heat generating member 51 of the 2nd layer, there exists an effect which suppresses the temperature fall of the gap | interval 57 part.

  The first layer heat generating member 51 and the second layer heat generating member 51 do not overlap with each other in the heating member 46 shown in FIGS. 8 and 9 and the heating member 46 formed on the single layer ceramic substrate 501 shown in FIG. Can also be applied.

  As described above, according to the heater and the fixing device according to the embodiment, the plurality of heat generating members in the heating member 46 (heater) ensure insulation between the heat generating members and reduce the occurrence of temperature unevenness. Can do.

In the present embodiment, the ceramic is described as an example of the heat-resistant insulating base material. However, the same effect can be obtained if the heat-resistant insulating base material is a glass / epoxy substrate or a glass / composite substrate. That is obvious. Further, for example, the upper layer above the heating resistor layer may be made of SiO ₂ .

(Second Embodiment)
Next, a heater and a fixing device according to the second embodiment will be described. In the heating member 46 in the second embodiment, the ceramic substrate has, for example, a multilayer structure, and a plurality of heating members 51 are arranged in the X direction on the first surface of the ceramic substrate (on the ceramic substrate of the first layer). A plurality of good thermal conductors 60 are arranged on the second surface (on the second layer ceramic substrate) so as to supplement the gaps between the plurality of heat generating members. The plurality of heat good conductors 60 on the second surface are members for temperature equalization, and constitute a heat radiator that passively generates heat (radiates stored heat).

  FIG. 13 is a view showing the configuration of the heating member 46 according to the second embodiment, and FIG. 13 (a) is a perspective view. The heating member 46 in FIG. 13A corresponds to an example in which heating members 51 having a certain width are arranged in the X direction, as shown in FIG.

As shown in FIG. 13A, the ceramic substrate 50 which is a heat-resistant insulating base material has a multilayer structure including a first layer ceramic substrate 501 and a second layer ceramic substrate 502. Then, the heating resistor layer is directly laminated on the first layer ceramic substrate 501 (or the glaze layer and the heating resistor layer are laminated on the first layer ceramic substrate 501). The heating resistance layer constitutes the heating member 51 and is formed of a known material such as TaSiO ₂ .

  On the second layer ceramic substrate 502, the heat good conductors 60 are arranged at predetermined intervals so as to supplement the gaps 56 between the heat generating members 51 on the first layer ceramic substrate 501. Yes. The good thermal conductor 60 is a member for soaking, which is made of a metal layer such as aluminum or copper, and generates heat when receiving heat from the heat generating member 51 of the first layer. That is, the good thermal conductor 60 constitutes a heat radiator that radiates passively held heat. The X-direction ends of the first layer heat generating member 51 and the second layer good thermal conductor 60 overlap each other.

Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is disposed in the X direction so that the gap 56 is hidden by the heat good conductor 60, and by transferring the heat of the heat generating member 51 to the heat good conductor 60, The temperature drop in the gap 56 is reduced. Thereby, the heating member 46 can be controlled to a uniform temperature. Further, a protective layer 503 may be provided on the second-layer ceramic substrate 502. The protective layer 503 is formed of, for example, Si ₃ N ₄ or SiO ₂ .

 FIG.13 (b) is sectional drawing of the heating member 46 seen from the arrow A direction of Fig.13 (a). As shown in FIG. 13B, the heat generating member 51 is formed on the ceramic substrate 501. The method for forming the heat generating member 51 (heat generating resistance layer) is the same as a known method (for example, a method for producing a thermal head), and a masking layer is formed of aluminum on the heat generating resistance layer. Adjacent heating members are insulated. The aluminum layers (electrodes 52a and 52b) are formed in a pattern that exposes the heat generating member 51 in the Y direction.

 A conductor 58 for wiring is connected to the aluminum layers (electrodes 52a and 52b) at both ends of each heat generating member 51. The conductor 58 is formed on the wiring pattern 59 formed on the ceramic substrate 501 by screen printing or the like and a through-hole pattern. The wiring pattern 59 is connected to the switching element of the driving IC 53. Therefore, power supply to each heat generating member 51 is performed from the drive source 54 via the wiring pattern 59, the conductor 58, and the switching element of the drive IC 53.

 On the second layer ceramic substrate 502, the heat good conductors 60 are arranged at a predetermined interval so as to supplement the gap 56 between the heat generating members 51 on the first layer ceramic substrate. . Further, a protective layer 503 is formed on the top so as to cover all of the good thermal conductor 60 and the like of the second layer ceramic substrate 502.

  FIG. 13C is a schematic cross-sectional view of the heating member 46 as viewed from the Y direction. As can be seen from FIG. 13C, the heating member 51 and the good thermal conductor 60 are disposed on the first and second ceramic substrates 501 and 502, respectively. The heating members 51 on the first-layer ceramic substrate 501 are arranged in the X direction of the ceramic substrate 501 with a gap 56 having a predetermined width.

  The good thermal conductors 60 arranged in the second layer are arranged at a predetermined interval so as to supplement the gap 56 in the first layer. The X-direction ends of the first layer heat generating member 51 and the second layer good thermal conductor 60 overlap each other. Therefore, when the heating member 46 is viewed from directly above, the heat generating member 51 is arranged so that the gap 56 is hidden by the good heat conductor 60, and the heat of the heat generating member 51 is transmitted to the good heat conductor 60, thereby The temperature drop is reduced. Thereby, the heating member 46 can be controlled to a uniform temperature.

  FIG. 13D is a schematic cross-sectional view showing another example of the heating member 46. The heating member 46 in FIG. 13D corresponds to the example shown in FIG. In FIG. 13D, only the heat generating members 511, 512, 514, and 516 are shown. The heat generating members 511, 513, 515, and 517 are bilaterally symmetric with respect to the arrangement of the heat generating members 511, 512, 514, and 516, and illustration thereof is omitted.

  In the example of FIG. 13D, the heating members 511, 512, 514, and 516 on the first-layer ceramic substrate 501 are arranged in the X direction of the ceramic substrate 501 with a gap 56 having a predetermined width. . The good thermal conductors 60 arranged on the second-layer ceramic substrate 502 are arranged so as to supplement the gap 56 of the first layer.

  The first layer heat generating members 511, 512, 514, and 516 and the second layer heat good conductor 60 overlap each other in the X direction. Therefore, the heat generating member 51 is arranged in the X direction so that the gap 56 is hidden by the good heat conductor 60, and the heat of the heat generating member 51 is transmitted to the good heat conductor 60 to reduce the temperature drop in the gap 56 portion.

  According to the fixing device according to the embodiment of FIG. 13, the plurality of heat generating members 51 in the heating member 46 ensure insulation between the heat generating members. The good thermal conductor 60 in the gap 56 portion passively generates heat by receiving heat from the heat generating member 51, thereby reducing the temperature drop in the gap portion and reducing the occurrence of temperature unevenness.

  Since the heat generated by the heating member 46 is diffused by the base material, the elastic layer, the surface protective layer, and the like of the fixing belt 41, the good heat conductor 60 is preferably disposed so as to straddle the gap 56 between the heat generating members 51. .

  In this embodiment, the heat generation in the portion corresponding to the image size has been described. However, the heater is subdivided and heated only where there is an image, or for some reason, it is heated while partially correcting the temperature difference. You can also

  FIG. 14 is a view showing a configuration of a modified example of the heating member 46 according to the second embodiment, and (a) is a perspective view. A heating member 46 in FIG. 14A has a plurality of heat generating members 51 arranged in the X direction on a first surface (back surface) of a single insulating substrate (for example, a ceramic substrate 501), and a second surface (front surface). The heat good conductors 60 are arranged in the X direction.

As shown in FIG. 14A, a heating resistor layer is directly laminated on the back surface of the ceramic substrate 501 (or a glaze layer and a heating resistor layer are laminated on the back surface of the ceramic substrate 501. Formed). The heating resistance layer constitutes the heating member 51 and is formed of a known material such as TaSiO ₂ . The heat generating members 51 are arranged in the longitudinal direction (X direction) with a predetermined gap 56 therebetween.

  In addition, the good thermal conductors 60 are arranged on the front surface of the ceramic substrate 501 at a predetermined interval so as to supplement the gap 56 between the heat generating members 51 formed on the back surface. The good thermal conductor 60 is a metal layer such as aluminum or copper. The heat generating member 51 on the back surface of the ceramic substrate 501 and the heat good conductor 60 on the front surface are arranged so that the end portions in the X direction overlap each other.

  Therefore, when the heating member 46 is viewed from directly above in the figure, the heat generating member 51 is disposed in the X direction so that the gap 56 is hidden by the heat good conductor 60, and by transferring the heat of the heat generating member 51 to the heat good conductor 60, The temperature drop in the gap 56 is reduced. Thereby, the heating member 46 can be controlled to a uniform temperature.

Further, a protective layer 503 may be provided on the front surface of the ceramic substrate 501 and a protective layer 504 may be provided on the back surface. The protective layers 503 and 504 are formed of, for example, Si ₃ N ₄ or SiO ₂ .

 FIG. 14B is a cross-sectional view of the heating member 46 as viewed from the direction of arrow A in FIG. As shown in FIG. 14B, the heat generating member 51 is formed on the back surface of the ceramic substrate 501. In addition, an aluminum layer (electrodes 52 a and 52 b) is formed in the Y direction of the heat generating member 51.

 A conductor 58 for wiring is connected to the electrodes 52 a and 52 b at both ends of each heating member 51, and the conductor 58 is connected to a wiring pattern 59 formed on the ceramic substrate 501 by screen printing or the like. These are connected to the switching elements of the drive IC 53, respectively.

 In FIG. 14, the wiring pattern 59 is not shown in detail for the purpose of mainly explaining the arrangement of the heat generating member 51 and the good thermal conductor 60. However, if the width of the ceramic substrate 501 in the Y direction is increased, the wiring pattern 59 is formed. Space can be secured. Thus, power is supplied to each heat generating member 51 from the drive source 54 via the wiring pattern 59, the conductor 58, and the switching element of the drive IC 53.

  FIG. 14C is a schematic cross-sectional view of the heating member 46 as viewed from the Y direction. As can be seen from FIG. 14C, the heat generating member 51 is disposed on the back surface of the ceramic substrate 501, and the heat good conductor 60 is disposed on the front surface.

  The heating members 51 formed on the back surface of the ceramic substrate 501 are arranged in the X direction of the ceramic substrate 501 with a gap 56 having a predetermined width. The good thermal conductors 60 arranged on the surface of the ceramic substrate 501 are arranged at a predetermined interval so as to supplement the gap 56 of the heat generating member 51. The heat generating member 51 on the back surface and the heat good conductor 60 on the front surface overlap each other in the X direction.

  Therefore, when the heating member 46 is viewed from directly above in the drawing, the heat generating member 51 is disposed such that the gap 56 is hidden by the good thermal conductor 60. The good thermal conductor 60 receives the heat from the heat generating member 51 and passively generates heat, thereby reducing the temperature drop in the gap 56 portion. Thereby, the heating member 46 can be controlled to a uniform temperature.

  FIG. 14D is a schematic cross-sectional view showing another example of the heating member 46. The heating member 46 in FIG. 14D corresponds to the example shown in FIG. In FIG. 14D, only the heat generating members 511, 512, 514, and 516 are shown. The heat generating members 511, 513, 515, and 517 are bilaterally symmetric with respect to the arrangement of the heat generating members 511, 512, 514, and 516, and illustration thereof is omitted.

  In the example of FIG. 14D, the heat generating members 511, 512, 514, and 516 formed on the back surface of the ceramic substrate 501 are arranged in the X direction of the ceramic substrate 501 with a gap 56 having a predetermined width. Further, the good thermal conductors 60 on the surface of the ceramic substrate 501 are arranged so as to supplement the gap 56.

  The heat generating members 511, 512, 514, 516 and the good heat conductor 60 overlap each other in the X direction. Therefore, the heat generating member 51 is arranged in the X direction so that the gap 56 is hidden by the good thermal conductor 60. The good thermal conductor 60 receives the heat from the heat generating member 51 and passively generates heat to reduce the temperature drop in the gap 56 portion.

  According to the fixing device according to the embodiment of FIG. 14, the plurality of heat generating members in the heating member 46 ensure insulation between the heat generating members. The good thermal conductor 60 in the gap 56 portion passively generates heat by receiving heat from the heat generating member 51, thereby reducing the temperature drop in the gap portion and reducing the occurrence of temperature unevenness.

  The heating member 46 in FIG. 14D corresponds to the example in FIG. 8, but the heating member 46 is formed on the first surface (for example, the back surface) of the ceramic substrate 501 so as to correspond to the example in FIG. 511, 512, 513, 514 may be arranged with a gap 56, and the good heat conductors 60 may be arranged alternately on the second surface (for example, on the surface).

  FIG. 15 is a schematic cross-sectional view showing another modification of the heating member 46. FIG. 15 shows a modification of the arrangement of the first layer heat generating member 51 and the second layer heat good conductor 60 in FIG. As can be seen from FIG. 15A, the heating member 51 and the good thermal conductor 60 are disposed on the ceramic substrates 501 and 502, respectively. The heating members 51 on the first-layer ceramic substrate 501 are arranged in the X direction of the ceramic substrate 501 with a gap 56 having a predetermined width.

  The first layer of heat generating members 51 and the good heat conductor 60 are alternately arranged in the vertical direction, but the width of the good heat conductor 60 in the X direction matches the gap 56 facing each other.

  Therefore, when the heating member 46 is viewed from directly above, the heat generating member 51 and the good thermal conductor 60 are arranged in the X direction without a break. That is, as shown in FIG. 10C, the first layer heat generating member 51 and the second layer heat good conductor 60 do not overlap, but the first layer gap 56 is formed by the second layer heat good conductor 60. Since it supplements, the temperature fall of the gap | interval 56 part can be suppressed.

  FIG. 15B is a further modification of the heating member 46. On the ceramic substrate 501 of the first layer, the heat generating members 51 are arranged in the X direction with a gap 56 having a predetermined width. The second layer of good thermal conductor 60 is arranged so as to supplement the gap 56.

  The first layer heat generating member 51 and the second layer heat good conductor 60 are alternately arranged in the vertical direction, but the X direction width of the heat good conductor 60 does not overlap the end portions in the X direction. The gap 56 is slightly smaller.

  Therefore, when the heating member 46 is viewed from directly above, the heat generating member 51 and the good thermal conductor 60 are arranged in the X direction with some breaks. As shown in FIG. 14C, the end portions of the first layer heat generating member 51 and the second layer heat good conductor 60 do not overlap, but most of the first layer gap 56 is heated by the second layer heat. Since it supplements with the good conductor 60, there exists an effect which suppresses the temperature fall of the space | gap 56 part.

  The first layer heat generating member 51 and the second layer heat generating member 51 do not overlap with each other in the heating member 46 shown in FIGS. 8 and 9 and the heating member 46 formed on the single layer ceramic substrate 501 shown in FIG. Can also be applied.

  FIG. 16 is a configuration diagram illustrating a modification of the fixing device 36 according to the embodiment. A fixing device 36 in FIG. 16 is obtained by replacing the fixing belt 41 in FIG. 3 with a cylindrical endless belt 411. The fixing device 36 includes a fixing belt 411 that is a cylindrical rotating body, and a press roller 42.

  The press roller 42 is rotated by a driving force transmitted by a motor (the direction of rotation is indicated by an arrow t in FIG. 16). As the press roller 42 rotates, the fixing belt 411 is driven to rotate (the direction of rotation is indicated by an arrow s in FIG. 10). A plate-like heating member 46 is provided inside the rotating body (fixing belt 411) so as to face the press roller 42.

  An arc-shaped guide 47 is provided inside the fixing belt 41, and the fixing belt 411 is attached along the outer periphery of the guide 47. The heating member 46 is supported by a support member 48 attached to the guide 47, and the heating member 46 contacts the inside of the fixing belt 411 and is pressed in the direction of the press roller 42. Therefore, a fixing nip having a predetermined width is formed between the fixing belt 411 and the press roller 42, and the toner image on the paper P is fixed to the paper P with heat and pressure when the paper P passes through the fixing nip.

  That is, the fixing belt 411 circulates around the heating member 46 while being supported by the guide 47. The heating member 46 has the basic configuration shown in FIG. 6, FIG. 8, or FIG. 9. As shown in FIG. 10 (or FIG. 13), the multilayer ceramic substrate 50 or FIG. 11 (or FIG. 14). As shown in FIG. 1, the ceramic substrate 501 having a single layer structure is formed.

  Hereinafter, a printing operation of the MFP 10 configured as described above will be described with reference to a flowchart of FIG. FIG. 17 is a flowchart illustrating a specific example of control of the MFP 10 according to the first embodiment.

  First, in Act 1 (operation 1), when the scanner unit 15 reads image data, the CPU 100 executes an image formation control program in the image forming unit 20 and a fixing temperature control program in the fixing device 36 in parallel.

  When the image forming process is started, Act 2 processes the read image data, and Act 3 writes an electrostatic latent image on the surface of the photosensitive drum 22. In Act 4, the developing device 24 develops the electrostatic latent image.

  On the other hand, when the fixing temperature control process is started, for example, based on the detection signal of the line sensor 40, the paper selection information by the operation panel 14a, the analysis result of the image data, etc., the CPU 100 determines the paper size in Act5. The size of the print range of the image data is determined. In Act 6, the fixing control circuit 150 selects a heat generating member group disposed at a position corresponding to the print range of the paper P as a heat generation target. For example, in the example shown in FIG. 7, fourteen heating members 51 arranged in the center corresponding to the width of the print area are selected.

  Next, when the temperature control start signal to the selected heat generating member group is turned ON at ACt7, the selected heat generating member group is energized and the temperature rises.

  Next, in Act 8, the surface temperature of the heat generating member group is detected by the temperature detection member 152 disposed inside or outside the fixing belt 41. Further, in Act 9, the CPU 100 determines whether or not the surface temperature of the heat generating member group is within a predetermined temperature range. Here, when it is determined that the surface temperature of the heat generating member group is within the predetermined temperature range (Act 9: Yes), the process proceeds to Act 10. On the other hand, when it determines with the surface temperature of a heat generating member group not being in a predetermined temperature range (Act9: No), it progresses to Act11.

  In Act 11, the CPU 100 determines whether or not the surface temperature of the heat generating member group exceeds a predetermined temperature upper limit value. Here, if it is determined that the surface temperature of the heat generating member group exceeds the predetermined temperature upper limit (Act 11: Yes), the CPU 100 turns off the power supply to the heat generating member group selected in the previous Act 6 in Act 12. And return to Act8.

  Further, when it is determined that the surface temperature of the heat generating member group does not exceed the predetermined temperature upper limit value (Act 11: No), the surface temperature is less than the predetermined temperature lower limit value from the determination result of Act 9, In Act 13, the CPU 100 maintains the energization of the heat generating member group in the ON state or turns it on again, and returns to Act 8.

  Next, in Act 10, the CPU 100 transports the paper P to the transfer unit in a state where the surface temperature of the heat generating member group is within a predetermined temperature range. In Act 14, the toner image is transferred to the paper P. Then, after the toner image is transferred to the paper P, the paper P is conveyed into the fixing device 36.

  Next, in Act 15, the fixing device 36 fixes the toner image on the paper P. In Act 16, the CPU 100 determines whether or not to end the image data printing process. Here, when it is determined that the printing process is to be ended (Act 16: Yes), in Act 17, the power supply to all the heat generating member groups is turned off, and the process ends. On the other hand, when it is determined that the printing process of the image data has not yet ended (Act 16: No), that is, when the image data to be printed remains, the process returns to Act 1 and the same process is repeated until the printing is completed.

  As described above, in the fixing device 36 according to the present embodiment, the heat generating member group of the heating member 46 (heater) is disposed in the direction (X direction) perpendicular to the paper transport direction Y and contacts the inside of the fixing belt 41. Arranged. Further, one of the heat generating member groups is selectively energized corresponding to the print range (image forming area) of the image data. Accordingly, abnormal heat generation of the non-sheet passing portion of the sheet of the heating member 46 can be prevented, and useless heating of the non-sheet passing portion can be suppressed, so that heat energy can be greatly reduced.

  Further, even if the heating members of the heating member 46 are arranged with a predetermined gap, the heating members supplemented in multiple layers and the heat good conductor layer can suppress the temperature drop in the gap portion so as to equalize the temperature. it can. Therefore, fixing quality can be improved.

  Incidentally, the formation of the heat generation resistance layer and the heat good conductor layer and the formation of the wiring pattern on the ceramic substrate 50 can be constituted by a LTCC (Low Temperature Co-fired ceramics) multilayer substrate. The LTCC multilayer substrate is known as a low-temperature fired multilayer ceramic substrate formed by simultaneously firing a wiring conductor and a ceramic base material at a low temperature of, for example, 900 ° C. or lower. Alternatively, it can be realized by forming a layer of a heat-resistant insulator by various film formation (thin film, thick film) processes.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 36 ... Fixing apparatus 41 ... Fixing belt (rotating body)
42 ... Pressure roller 46 ... Heating member (heater)
501, 502 ... ceramic substrate 51 ... heating members 531 to 537 ... drive IC
60 ... Thermal conductor

Claims (6)

A heat-resistant insulating substrate;
A plurality of heat generating members arranged in a first direction on the first surface of the insulating base;
A thermal radiator that radiates heat that is actively or passively disposed on a surface different from the first surface of the insulating base so as to supplement a gap portion between the plurality of heat generating members;
A heater comprising:   2. The heater according to claim 1, wherein the thermal radiator is a heating member provided at a position corresponding to the gap portion and arranged to overlap an end portion of the heating member in the first direction.   The heater according to claim 2, wherein the heat generation amount of the plurality of heat generation members and the heat generation amount of the heat generation member constituting the heat radiator are set to be different.   2. The heater according to claim 1, wherein the heat radiator is formed of a good thermal conductor provided at a position corresponding to the gap portion and arranged to overlap an end portion of the heat generating member in the first direction. The insulating base material has a multilayer structure,
Arranging the plurality of heat generating members in a first direction on the surface of the first layer of the insulating substrate;
The heater according to claim 1, wherein the thermal radiator is disposed on a surface of a second layer adjacent to the first layer of the insulating base. An endless rotator disposed in a first direction orthogonal to the conveyance direction of the recording medium on which the image is formed;
The heat insulating insulating base, the first surface of the insulating base, the plurality of heating members arranged on the first surface, and the first portion of the insulating base so as to supplement gap portions between the plurality of heating members. A heat radiator that radiates heat that is actively or passively stored and that contacts the inside of the rotating body and heats the rotating body. Heating device.

Images