JP6982402B2 - Heater, heating device - Google Patents

Description

The embodiments described herein relate to techniques for protecting the electrode layer of the heater.

There is a fixing device that sandwiches a sheet between a pressure roller and a belt (for example, Patent Document 1). In this fixing device, a plate-shaped heater contacts the inner surface of the belt and heats the belt. On the substrate of the heater, there is a heating layer along the longitudinal direction of the heater. On both sides of the heating layer in the lateral direction of the heater, there are electrode layers for driving the heating layer. There is a protective layer on the heat generating layer.

Japanese Unexamined Patent Publication No. 2015-219417

In the conventional heater, when the protective layer is worn due to the belt sliding on the protective layer, the electrode layer may come into contact with the belt and cause a short circuit.

The embodiment aims to provide a technique for protecting the electrode layer of the heater.

According to the embodiment, the heater includes a base portion, a protruding portion, a heat generating layer, a first protective layer, and an electrode layer. The protruding portion protrudes from the base portion. The heating layer is on the protrusion. The first protective layer is on the heat generating layer. The electrode layer is on the base portion and drives the heat generating layer.

According to the embodiment, the heating device includes a pressurizing member, a belt, and a heater. The belt sandwiches and conveys the sheet together with the pressurizing member, and heats the sheet to fix the image on the sheet to the sheet. The heater includes a base portion, a protruding portion protruding from the base portion, a heat generating layer on the protruding portion, a protective layer on the heat generating layer, and an electrode layer on the base portion that drives the heat generating layer. Be prepared.

It is a schematic diagram of an image forming apparatus. It is a figure which shows the structural example of the fixing device. It is a top view which shows the arrangement of the resistance heat generation layer and the electrode layer of a planar heater. It is sectional drawing which shows the structure of the planar heater. It is a figure which shows the other structural example of a fixing device.

Hereinafter, embodiments will be described with reference to the drawings.
(First Embodiment)
FIG. 1 is a schematic diagram of the image forming apparatus 1.
The image forming apparatus 1 has a reading unit R, an image forming unit P, and a paper cassette unit C. The reading unit R reads the document sheet installed on the 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 the original image read by the reading unit R or print data from an external personal computer, and forms and fixes a toner image on the sheet.

The image forming unit P includes a laser scanning unit 200 and photosensitive drums 201Y, 201M, 201C, 201K. The laser scanning unit 200 has a polygon mirror 208 and an optical system 241 and is formed on a sheet based on image signals of each color of yellow (Y), magenta (M), cyan (C), and black (K). The image is applied to 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 above irradiation position. The photosensitive drums 201Y to 201K sequentially transfer the retained toner image to the transfer belt 207. The transfer belt 207 is an endless belt, and the roller 213 is rotationally driven to convey the toner image to the transfer position T.

The transport path 101 transports the sheets stocked in the paper feed cassette unit C in the order of the transfer position T, the fixing device 30 (heating device), and the discharge tray 211. The sheet stocked in the paper cassette unit C is conveyed to the transfer position T by the guidance of the transfer 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 transfer path 101. The fixing device 30 heats and melts the toner image to permeate the toner image into the sheet and fix it. This prevents the toner image on the sheet from being disturbed by an external force. The transport path 101 transports 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 102 is a unit that comprehensively controls the devices and mechanisms in the image forming device 1, and includes, for example, a central processing unit such as a CPU (Central Processing Unit) and a volatile / non-volatile storage device. As one embodiment, the central processing unit controls the device and the mechanism in the image forming apparatus 1 by performing arithmetic execution on the program stored in the storage device. Further, a part of the function may be implemented as a circuit.

The transfer unit 9 is configured to include each unit until the image (toner image) to be formed is conveyed to the transfer position T and transferred onto the sheet.

FIG. 2 is a diagram showing a configuration example of the fixing device 30.
The fixing device 30 has a plate-shaped planar heater 100 and an endless belt 34 suspended by a plurality of rollers. Further, the fixing device 30 has a drive roller 33 that suspends the endless belt 34 and drives it to rotate in a certain direction. The fixing device 30 has a tension roller 35 that suspends and applies tension to the endless belt 34. Further, the fixing device 30 has a pressure roller 31 (pressure member) having an elastic layer formed on the surface thereof.

The planar heater 100 is located at a position facing the pressure roller 31 with the endless belt 34 interposed therebetween, and is pressed toward the pressure roller 31 side. The planar heater 100 contacts the inner surface of the endless belt 34 and heats the endless belt 34. The endless belt 34 heats the sheet by sandwiching the sheet in the contact portion (nip portion) with the pressure roller 31. The endless belt 34, together with the pressure roller 31, conveys the sheet to the downstream side in the sheet conveying direction. The endless belt 34 fixes the toner image on the sheet to the sheet. That is, the endless belt 34 sandwiches and conveys the sheet together with the pressure roller 31, heats the sheet, and fixes the image on the sheet to the sheet.

The endless belt 34 has 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) in order from the side in contact with the planar heater 100. : It is composed of each layer having a thickness of 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 is a plan view showing the arrangement of the resistance heating layer 5 and the electrode layer 6 of the planar heater 100. Hereinafter, the direction that is the sheet transport direction and is also the lateral direction of the planar heater 100 (base portion 42 (FIG. 4)) is referred to as the Z direction (second direction). The direction that is the width direction of the sheet and is also the longitudinal direction of the planar heater 100 (base portion 42) is defined as the Y direction (first direction). The Y direction is orthogonal to the Z direction. The direction toward the pressure roller 31 and the vertical direction of the base portion 42 is defined as the X direction. The X direction is orthogonal to the Z direction and the Y direction.

The planar heater 100 includes a ceramic substrate 4 (layered body) extending in the Y direction. The substrate 4 is arranged so as to face the surface of the sheet 105 to be conveyed via the endless belt 34. In the substrate 4, the resistance heating layer 5 and the electrode layer 6 are formed on the surface 41 in contact with the endless belt 34.

A plurality of resistance heating layers 5 are formed at intervals in the Y direction. The resistance heating layer 5 generates heat when energized. The resistance heating layer 5 is long in the Z direction in a plan view.

The electrode layer 6 is formed on both ends of the resistance heating layer 5 in the Z direction. The electrode layer 6 applies a DC or AC voltage to the resistance heat generation layer 5 to drive the resistance heat generation layer 5. The electrode layer 6 is made of, for example, aluminum. Wiring is connected to each electrode layer 6. Each electrode layer 6 is connected to a control circuit that controls the electrode layer 6 via wiring.

A part of the electrode layer 6 is laminated on the resistance heating layer 5 (see FIG. 4). The electrode layer 6 may be divided in the Y direction for each resistance heating layer 5 or for each resistance heating layer 5 so that they can be individually driven.

FIG. 4 is a cross-sectional view showing the configuration of the planar heater 100.
The substrate 4 includes a base portion 42 extending in the Y direction and a step forming portion 43 (protruding portion) extending in the Y direction. The step forming portion 43 protrudes from the base portion 42 in the X direction and extends in the Y direction. The base portion 42 and the step forming portion 43 are separate bodies, and are green sheets having different thicknesses in the X direction. The green sheet is a heat-resistant ceramic.

Both green sheets can be combined by stacking the green sheet constituting the base portion 42 and the green sheet constituting the step forming portion 43 and then firing the green sheet under pressure from both sides in the X direction. The thickness of the base portion 42 is larger than the thickness of the step forming portion 43.

The base portion 42 may be a single layer, and the base portion 42 and the step forming portion 43 in FIG. 4 may be integrated. The base portion 42 and the step forming portion 43 may be formed by cutting both ends of the substrate 4 in the Z direction along the Y direction.

The surface 41 having the step forming portion 43 of the substrate 4 has a first surface 44 which is an upper surface of the step forming portion 43 and a second surface 45 which is on both sides of the first surface 44 in the Z direction and is lower than the first surface 44. Be prepared. The resistance heating layer 5 is formed on the first surface 44, and the electrode layer 6 is formed on each second surface 45. A part of the electrode layer 6 is laminated on the resistance heating layer 5.

The electrode layers 6 are on both sides of the step forming portion 43 in the Z direction and extend in the Y direction. As described above, the electrode layer 6 may be divided in the Y direction in order to control the resistance heating layer 5 individually or in several groups individually or in groups. Further, the electrode layers 6 are on both sides of the step forming portion 43 in the Z direction, but the portions connected to the resistance heating layer 5 are on the step forming portion 43.

The electrode layer 6 includes a first electrode layer 61, a second electrode layer 62, and a connecting portion 63.

The first electrode layer 61 is on the base portion 42.
The second electrode layer 62 is on the step forming portion 43. A part of the second electrode layer 62 is laminated on the end portion of the resistance heating layer 5 in the Z direction and connected to the end portion.
The connecting portion 63 extends in the X direction, and has an end portion of the first electrode layer 61 located on the central side of the base portion 42 in the Z direction and a second electrode layer 62 located on the end side of the base portion 42 in the Z direction. Connect with the end.

A protective layer 7 is formed on the resistance heating layer 5 and the electrode layer 6. The protective layer 7 is formed of, for example, SiO2. An endless belt 34 slides on the protective layer 7. The protective layer 7 prevents the endless belt 34 from coming into contact with the resistance heating layer 5 and the electrode layer 6.

The protective layer 7 includes a first protective layer 71 and a second protective layer 72. The first protective layer 71 is formed on the resistance heating layer 5. The second protective layer 72 is a sealing layer of the electrode layer 6 and is formed on the electrode layer 6 on the second surface 45. Specifically, the first protective layer 71 is formed on the resistance heating layer 5 and on the second electrode layer 62 and the connecting portion 63 in the electrode layer 6. The second protective layer 72 is formed on the first electrode layer 61.

The height of the top surface 721 of the second protective layer 72 from the base portion 42 is lower than the height of the top surface 711 of the first protection layer 71 from the base portion 42. The top surface 721 of the second protective layer 72 may be flush with the top surface 711 of the first protection layer 71.

In the above embodiment, the position of the resistance heat generation layer 5 can be raised by the step forming portion 43, and the resistance heat generation layer 5 can be positioned higher than the electrode layer 6. Therefore, in the embodiment, the electrode layer 6 (first electrode layer 61) can be formed at a position lower than the resistance heating layer 5. Therefore, in the embodiment, when the protective layer 7 becomes thin due to wear, the electrode layer 6 (first electrode layer 61) is compared with the case where the resistance heating layer 5 and the electrode layer 6 are on the same height surface. The exposure of the electrode layer 6 can be suppressed, and the electrode layer 6 can be further protected.

In the embodiment, the position of the resistance heat generation layer 5 can be raised by the step forming portion 43, and the resistance heat generation layer 5 can be positioned higher than the electrode layer 6. Therefore, in the embodiment, the height of the top surface 711 of the first protective layer 71 on the resistance heating layer 5 can be easily set to be higher than the height of the top surface 721 of the second protective layer 72 on the electrode layer 6. Thereby, in the embodiment, the endless belt 34 can be brought into contact with the first protective layer 71, and the endless belt 34 can be prevented from floating from the first protective layer 71. Therefore, in the embodiment, the heat transfer efficiency from the resistance heating layer 5 to the endless belt 34 can be improved.

In the embodiment, since the endless belt 34 is in contact with the first protective layer 71, the wear of the second protective layer 72 can be reduced as compared with the conventional case where the endless belt 34 is lifted from the first protective layer 71. Therefore, in the embodiment, it is possible to prevent the second protective layer 72 from being worn and the electrode layer 6 from coming into contact with the endless belt 34, and it is possible to suppress the occurrence of a short circuit due to the contact between the electrode layer 6 and the endless belt 34.

(Second Embodiment)
FIG. 5 is a diagram showing a configuration example of the fixing device 30A.
The film guide 36 has a semi-cylindrical shape, and accommodates the planar heater 100 in the recess 361 on the outer peripheral surface.

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

The planar heater 100 comes into contact with the fixing film 34A and heats the fixing film 34A.

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

In each of the above embodiments, the step forming portion 44 has been described as an example of the protruding portion. However, the protruding portion does not have to be rectangular in cross-sectional view and may have any shape in cross-sectional view as long as it protrudes from the base portion 42 in the X direction and a heat generating layer is formed on the upper surface. For example, the protruding portion may have the same cross-sectional shape as the step forming portion 44, but both ends in the Z direction on the upper surface may be rounded. Further, the corner portion formed by the protruding portion and the base portion 42 may also be rounded.

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

The present invention can be practiced in various other forms without departing from its spirit or key features. Therefore, the above embodiments are merely exemplary in all respects and should not be construed in a limited way. The scope of the present invention is shown by the scope of claims and is not bound by the text of the specification. Moreover, all modifications, various improvements, substitutions and modifications that fall within the equivalent scope of the claims are all within the scope of the present invention.

1 ... Image forming device, 5 ... Heat generating layer, 6 ... Electrode layer, 7 ... Protective layer, 9 ... Transfer section, 30, 30A ... Fixing device (heating member), 31 ... Pressurized roller (pressurizing member), 34 ... Endless belt (belt), 34A ... Fixing film (belt), 41 ... Substrate, 42 ... Base part, 43 ... Step forming part (protruding part), 71 ... First protective layer, 72 ... Second protective layer, 100 ... Surface Shaped heater, Y ... Y direction (longitudinal direction), Z ... Z direction (short direction).

Claims (5)

A heater that heats the sheet and heats the belt that fixes the image formed on the sheet to the sheet while sandwiching and transporting the sheet together with the pressurizing member.
With the base part
A protrusion protruding from the upper surface of the base portion and a protrusion
The heat generating layer on the upper plane of the protrusion and
A first protective layer that is in contact with the upper surface of the heat generating layer, covers the upper surface of the heat generating layer, and is in sliding contact with the belt on the upper surface.
An electrode layer that is in contact with the upper surface of the base portion, the upper surface of the heat generating layer, and the upper plane of the protruding portion to drive the heat generating layer, and
A heater equipped with. The heater according to claim 1, further comprising a second protective layer that is on the electrode layer and whose top surface is lower than the top surface of the first protective layer. The heater according to claim 1 or 2, wherein the protruding portion is a separate body from the base portion. The protrusion extends in the longitudinal direction of the base and extends.
The electrode layers are on both sides of the protrusion in the lateral direction of the base.
The electrode layer is
The first electrode layer on the base portion and
One of claims 1 to 3, wherein the second electrode layer is provided on the protruding portion, is connected to the first electrode layer, and is connected to the end portion of the heat generating layer in the lateral direction. The heater described. Pressurizing member and
A belt that sandwiches and conveys the sheet together with the pressurizing member, heats the sheet, and fixes the image formed on the sheet to the sheet.
A heater that heats the belt by sandwiching the belt and facing the pressurizing member.
With the base part
A protrusion protruding from the upper surface of the base portion and a protrusion
A heating layer on the flat surface on the projecting portion,
A first protective layer that is in contact with the upper surface of the heat generating layer, covers the upper surface of the heat generating layer, and is in sliding contact with the belt on the upper surface.
An electrode layer that is in contact with the upper surface of the base portion, the upper surface of the heat generating layer, and the upper plane of the protruding portion to drive the heat generating layer, and
With a heater and
A heating device equipped with.

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