JPH0855674A - Heater device, fixing device, and image forming device - Google Patents

Abstract

PURPOSE:To fix toner on a sheet smoothly. CONSTITUTION:A fixing device of a page printer is composed of a pressing roller, a fixing sheet facing this pressing roller, and a fixing heater 41 provided to be fixed on the inner side of the fixing sheet. The fixing heater 41 comprises a resistance heat generation body 45 printed and formed along length on a thin and long rectangular base plate part 44, and a pair of electrode parts 46 formed along both side parts of the resistance heat generation body 45. The resistive heating element 45 and the electrode parts 46 are covered with an overcoat layer 51 of glass. The upper side of the resistive heating element 45 is protruded from the upper side of the electrode part 46. Slide resistance between the fixing heater 41 and the fixing sheet can thus be reduced to carry sheets smoothly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a heater device that heats toner to fix an image, a fixing device, and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a page printer or a copying machine, a toner image formed on a photosensitive drum is transferred onto a sheet of paper, and the toner image is heated and pressed by a fixing device to form an image on the sheet of paper. It is known that the configuration is fixed in the.

As the fixing device, a cylindrical fixing sheet, an elongated flat plate-shaped heater device disposed inside the fixing sheet, and a fixing sheet are provided to face the heater device. There is known a configuration including a pressing roller. Further, in this fixing device, when the sheet on which the toner image is transferred is conveyed between the fixing sheet and the pressing roller, the toner image is pressed between the heater device and the pressing roller and is heated by the heater device. The toner image is fused to the paper to fix the toner image on the paper.

In the heater device, a resistance heating element made of silver-palladium alloy or the like is formed along a longitudinal direction of the substrate on an insulating rectangular plate-like substrate made of alumina ceramics or the like. The resistance heating element is made to generate heat by applying a predetermined voltage between the electrode portions provided at both ends of the heating element in the longitudinal direction.

[0005]

However, in the above-mentioned conventional structure, since the fixing sheet and the sheet move between the fixedly provided flat heater device and the pressing roller, the sliding resistance is increased. There is a problem that the sheet becomes large and it is difficult to smoothly convey the sheet.

The present invention has been made in view of the above circumstances, and provides a heater device capable of reducing the sliding resistance with respect to an object to be heated, and heating the object to be fixed on the object to be printed smoothly. An object of the present invention is to provide a fixing device and an image forming apparatus capable of fixing.

[0007]

According to a first aspect of the present invention, there is provided a heater device in which a substrate portion, an elongated heat generating portion provided on the substrate portion, and both side portions of the heat generating portion along the longitudinal direction are provided. A pair of electrode portions that are provided on the substrate portion and that are electrically connected to the heat generating portion, respectively, and a surface portion located above the heat generating portion has a surface portion located above the electrode portion. Is also projected on the upper side.

A heater device according to a second aspect is the heater device according to the first aspect, wherein each electrode portion is provided with a plurality of lead portions electrically connected to the heat generating portion, and these lead portions are the heat generating portion. Are alternately connected to both side portions of the heating element along the longitudinal direction of the heat generating portion with a predetermined gap therebetween.

A heater device according to a third aspect of the present invention is the heater device according to the first or second aspect, in which an overcoat layer having higher abrasion resistance than the heat generating portion is formed at least above the heat generating portion. is there.

A heater device according to a fourth aspect is the heater device according to any one of the first to third aspects, in which the substrate portion is
The heating member has a substantially flat plate shape, and the protruding dimension of the heat generating portion from the substrate portion is larger than the protruding dimension of each electrode portion from the substrate portion.

A heater device according to a fifth aspect is the heater device according to any one of the first to fourth aspects, in which a recessed portion is formed along a longitudinal direction on a surface portion located above the heat generating portion. Is.

The fixing device according to claim 6 is a fixing device for heating an object to be fixed imaged on an object to be printed and fixing the object to be printed on the object to be printed, wherein the heater device according to any one of claims 1 to 5. And a pressing unit that is provided so as to face the heater device and presses the printing object toward the heater device.

According to a seventh aspect of the present invention, there is provided an image forming apparatus that supplies a material to be printed, a transfer device that transfers an image of the material to be fixed onto the material to be printed, and the object to be fixed by heating the material to be printed. The fixing device according to claim 6 for fixing

[0014]

In the heater device according to the first aspect of the present invention, since the surface portion located above the heat generating portion is provided above the surface portion located above the electrode portion, this heater device and this heater device are provided. The sliding resistance between the object to be heated and the sliding contact is reduced. Further, since the elongated heat generating portion is provided on the substrate portion and the pair of electrode portions are provided on both sides of the heat generating portion along the longitudinal direction, the heat conducted from the heat generating portion is radiated by these electrode portions. .

According to the heater device of claim 2,
In addition to the described action, each electrode portion is electrically connected to the heat generating portion through a plurality of lead portions which are alternately provided on both sides of the heat generating portion and are arranged at predetermined intervals along the longitudinal direction of the heat generating portion. Since it is connected to, the current flows along the longitudinal direction of the heat generating portion.

According to the heater device of claim 3,
Alternatively, in addition to the effect described in 2, the overcoat layer having stronger abrasion resistance than the heat generating portion is formed at least on the upper side of the heat generating portion. Protected against abrasion.

According to the heater device of claim 4,
In addition to the effect described in any one of 1 to 3, since the heat generating portion is provided so as to be larger than each electrode portion, the surface portion located above the heat generating portion is projected above the surface portion located above the electrode portion. Easy to set up.

According to the heater device of claim 5,
In addition to the operation described in any one of 4 to 4, since a concave portion is formed along the longitudinal direction on the surface portion located above the heat generating portion, when the object to be heated is pressed against this heater device, the object to be heated is heated. The contact area between the object and the part that generates heat increases.

Since the fixing device according to the sixth aspect includes the heater device according to any one of the first to fifth aspects and the pressing unit that presses the printed material to the heater device side, the printed material printed on the printed material is provided. When the fixing material is heated and fixed on the printing material, the printing material is conveyed smoothly.

According to another aspect of the image forming apparatus of the present invention, a supply device for supplying a material to be printed, a transfer device for transferring an image of the material to be fixed onto the material to be printed, and a material to be printed are heated to fix the material to be fixed. Since the fixing device according to claim 6 is provided,
When the object to be fixed transferred onto the object to be printed is heated and fixed on the object to be printed, the object to be printed is conveyed smoothly.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A heater device, a fixing device, and an image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 4, reference numeral 11 denotes a page printer as an image forming apparatus, and the page printer 11 has a supply device 15, a transfer device 16, and a fixing device 17 along a conveyance path of a paper 12 as an object to be printed. Are arranged.

The supply device 15 is provided with a paper feed cassette 21, and separates the papers 12 stacked in the paper feed cassette 21 and supplies them.

The transfer device 16 includes a photosensitive drum 23, an optical system (not shown), a developing device 24, a transfer corotron 25, and a cleaner which are sequentially arranged along the peripheral surface of the photosensitive drum 23.
26, a charge eliminating lamp 27, and a charging corotron (not shown). Then, in the transfer device 16, an electrostatic latent image of an image is formed on the photosensitive drum 23 charged by the charging corotron by the optical system, and the electrostatic latent image is developed by the developing device 24.
As a result, the toner 31 as an object to be fixed is attached to form a toner image. Next, transfer corotron 25 to photosensitive drum
The toner image on 23 is transferred onto the conveyed paper 12. After that, the photosensitive drum 23 is cleaned by the cleaner 26 and discharged by the discharge lamp 27.

Further, the fixing device 17 pressurizes and heats the paper 12 on which the toner image is transferred to dissolve the microcapsules contained in the toner 31 and fix the microcapsules on the paper 12.

As shown in FIGS. 3 and 4, the fixing device 17 includes a pressing roller 33 as a pressing means provided on the lower side of the conveying path, and a pressing roller 33 sandwiching the conveying path.
A cylindrical fixing sheet 34 as an object to be heated which is provided so as to face 33 and a heater 35 which is provided inside the fixing sheet 34 are provided. The fixing sheet 34 is formed, for example, by coating polyimide with resin.
The paper 12 is conveyed between the fixing sheet 34 and the pressing roller 33 by rotationally driving the pressing roller 33 and the pressing roller 33.

Further, the heater 35 has a fixing heater 41 as a heater device and a mounting base 42 for fixedly supporting the fixing heater 41. Then, the fixing heater 41 is
As shown in FIGS. 1 and 2, the alumina ceramic (A
l ₂ O ₃₎ made of, has a glass substrate 44 which forms the glaze bets ceramic elongated rectangular flat plate shape or to form a smooth glass layer on the upper surface of the alumina ceramic.

On the upper surface of the substrate portion 44, a thick film of a resistance heating element 45 as a heating portion is formed by printing, which is located at the center portion in the width direction and extends over almost the entire length in the longitudinal direction.
The resistance heating element 45 is made of a silver-palladium alloy (Ag /
Pd) or ruthenium oxide (RuO ₂ )
Laminated to have a predetermined height. Further, on the upper surface of the resistance heating element 45, there is formed a recessed portion 45a which is located in the central portion in the width direction and is recessed downward (toward the substrate portion 44 side) over substantially the entire length in the longitudinal direction. There is.

On the upper surface of the substrate portion 44, a thick film of a pair of electrode portions 46, 46 is formed by printing along both sides of the resistance heating element 45. And these electrode parts 46 are made of gold (A
u), silver (Ag), platinum (Pt), etc., and is formed to have a smaller thickness than the resistance heating element 45 by firing a metal organic paste mainly composed of an organic material. Further, each electrode portion 46 is composed of an electrode main body portion 47 provided apart from the resistance heating element 45, and a large number of lead portions 48 integrally or separately provided from the electrode main body portion 47 so as to project integrally. Has been formed. Then, the lead portion 48 is provided so as to project from each electrode body portion 47 in a direction orthogonal to the longitudinal direction of the electrode body portion 47, and to be provided in a comb-tooth shape at a predetermined interval from each other, The resistance heating elements 45 are laminated and formed on the lead parts 48 protruding from the electrode parts 46 on both sides, and are alternately connected to both sides of the resistance heating elements 45. Further, a terminal portion 49 is formed of silver-palladium alloy (Ag / Pd) or the like at one end portion in the longitudinal direction of each electrode main body portion 47, and is connected to a power supply line (not shown) by soldering or the like. ing.

Furthermore, a resistance heating element is formed on the upper surface of the substrate section 44.
A thick film of a glass overcoat layer 51 having higher abrasion resistance than the resistance heating element 45 is formed so as to cover 45 and each electrode portion 46. And this overcoat layer 51
Are formed so as to expose the respective terminal portions 49, except for both end portions of the substrate portion 44, over substantially the entire length in the longitudinal direction and the entire length in the width direction of the substrate portion 44. Further, as shown in FIG. 1, the difference L in the protrusion dimension from the substrate portion 44 between the portion covering the resistance heating element 45 and the portion covering each electrode portion 46 is set to about 10 microns. Further, in the portion covering the resistance heating element 45, a recessed portion 51a is formed along the shape of the recessed portion 45a of the resistance heating element 45.

In the fixing heater 41, a resistance heating element is generated by applying a predetermined voltage to the terminal portions 49 at both ends.
A predetermined current is supplied to 45 to obtain a predetermined amount of heat generation. The sheet resistance value of the resistance heating element 45 of this embodiment is about 1 kΩ / □, and the resistance value of the terminal portion 49 is set to 7.4 Ω.

In the fixing heater 41, the portion of the overcoat layer 51 covering the resistance heating element 45 is pressed against the pressing roller 33 via the fixing sheet 34, and the fixing heater 41 is conveyed between the fixing sheet 34 and the pressing roller 33. Resistance paper 45
The heat generated in is added.

According to the present embodiment, the resistance heating element 45
Since the surface portion of the fixing heater 41 and the fixing sheet 34 slidably contacting the fixing heater 41 are protruded above the surface portion of each electrode portion 46 by about 10 microns. The fixing sheet 34 can be smoothly slid by reducing the sliding resistance between the sheets, and the sheet 12 pressed against the fixing heater 41 can be smoothly conveyed through the fixing sheet 34.

Further, the fixing sheet 34 slidably contacting the fixing heater 41 and the fixing heater 41 via the fixing sheet 34
The sheet 12 pressed against the sheet is pressed against only the portion that covers the resistance heating element 45, that is, the portion that generates heat, so that the thermal efficiency can be improved.

Further, since the fixing heater 41 is formed such that the resistance heating element 45 projects from the substrate portion 44 more than the electrode portions 46, the overcoat layer 51 having a substantially uniform thickness is formed on the surface portion. As a result, the surface portion located above the resistance heating element 45 can be more easily provided than the surface portion located above each electrode portion 46.

Further, on the upper surface of the resistance heating element 45, a recessed portion 45a is formed in the central portion in the width direction along the longitudinal direction, and the overcoat layer 51 is also formed along the shape of this recessed portion 45a. A recessed portion 51a is formed. Therefore, this fixing heater
41, when the paper 12 is pressed against the fixing sheet 34,
The contact area between the heat generating portion and the paper 12 is increased, and the paper 12 can be efficiently heated. Further, by forming the curved concave portion 45a on the upper surface of the overcoat layer 51, an effect of improving the paper separation of the paper 12 is expected.

In the above embodiment, the difference L in the protruding dimension between the portion covering the resistance heating element 45 and the other portions is set to about 10 microns, but the difference L in the protruding dimension is 5 microns to 6 microns.
It may be in the range of 0 micron, more preferably 10
It may be in the range of 30 to 30 microns. That is, if the difference L in the protrusion size is less than 5 microns, the effect of reducing the sliding resistance is small, and if it is 10 microns or more,
The sliding resistance can be reduced sufficiently. On the other hand, it is difficult to form the protrusion dimension difference L larger than 30 microns, and it is more difficult to form the protrusion size larger than 60 microns, which increases the manufacturing cost of the fixing heater 41.

Further, for example, the resistance heating element 45 and the electrode portion 46 have the same thickness dimension, and the overcoat layer 51 covering the resistance heating element 45 and the overcoat layer 51 covering the other portions.
It is also possible to set the difference L between the protrusion dimensions by forming the difference in thickness. Furthermore, the upper surface of the resistance heating element 45 may be planar and the recessed portion 51a may be formed only on the upper surface of the overcoat layer 51.

Since the fixing heater 41 has the elongated resistance heating element 45 formed on the substrate section 44 and the pair of electrode sections 46 along the longitudinal direction on both sides of the resistance heating element 45, The heat conducted from the resistance heating element 45 to the substrate section 44 is radiated by these electrode sections 46, the temperature gradient becomes steep, and the temperature can be drastically lowered as the distance from the resistance heating element 45 increases. Therefore, the paper 12 to which the toner 31 has been transferred can be locally heated only near the resistance heating element 45, reducing the thermal influence on the paper 12 and curving (curling) the paper 12. Can be suppressed.

Further, each electrode portion 46 has a large number of lead portions 48 formed alternately on both sides of the resistance heating element 45 and along the longitudinal direction of the resistance heating element 45 at predetermined intervals. Since the resistance heating element 45 is electrically connected to the resistance heating element 45, a current can flow along the longitudinal direction of the resistance heating element 45, and the control of the heat generation state of the resistance heating element 45 can be facilitated.

In the above embodiment, the fixing heater 41 and the pressing roller 33 are opposed to each other with the fixing sheet 34 interposed therebetween.
The fixing heater 41 and the pressing roller 33 can be directly opposed to each other without interposing the fixing sheet 34.

As the image forming apparatus, in addition to the page printer 11, a copying machine, a facsimile machine, or the like is used.
It can be applied to electrophotographic devices using the 31.

[0043]

According to the heater device of the first aspect, since the surface portion located above the heat generating portion is projected above the surface portion located above the electrode portion, this heater device and this It is possible to smoothly move the object to be heated by reducing the sliding resistance between the object to be heated and the sliding contact with the heater device. Further, since the elongated heat generating portion is provided on the substrate portion and the pair of electrode portions are provided on both sides of the heat generating portion along the longitudinal direction, the heat conducted from the heat generating portion can be radiated by these electrode portions. it can.

According to the heater device of the second aspect, in addition to the effect of the first aspect, the electrode parts are alternately arranged on both sides of the heat generating part and at predetermined intervals with respect to each other along the longitudinal direction of the heat generating part. Since it is electrically connected to the heat generating portion via the plurality of lead portions provided via the heat generating portion, it is possible to make a current flow along the longitudinal direction of the heat generating portion and to easily control the heat generating state of the heat generating portion.

According to the heater device of the third aspect, in addition to the effect of the first or second aspect, since the overcoat layer having stronger abrasion resistance than the heat generating portion is formed at least above the heat generating portion, By this overcoat layer, it is possible to protect the heat generating part from abrasion when it comes into sliding contact with the object to be heated.

According to the heater device of the fourth aspect, in addition to the effect of any one of the first to third aspects, since the heat generating portion is protruded larger than each electrode portion, the surface portion located above the heat generating portion is formed. The electrode portion can be easily projected above the surface portion located above the electrode portion.

According to the heater device of the fifth aspect, in addition to the effect of any one of the first to fourth aspects, the concave portion is formed along the longitudinal direction on the surface portion located above the heat generating portion. When the object to be heated is pressed against this heater device,
By increasing the contact area between the object to be heated and the part that generates heat, the object to be heated can be efficiently heated.

According to the fixing device of the sixth aspect, the heater device according to any one of the first to fifth aspects and the pressing means for pressing the printed material to the heater device side are provided. Therefore, the fixing device is printed on the printed material. When the object to be fixed is heated and fixed on the object to be printed, the object to be printed can be conveyed smoothly.

According to the seventh aspect of the present invention, there is provided a supply device for supplying an object to be printed, a transfer device for transferring an image of the object to be fixed onto the object to be printed, and the object to be fixed by heating the object to be printed. Since the fixing device according to the sixth aspect of the invention is provided for fixing, the object to be printed can be conveyed smoothly when the object to be fixed transferred onto the object to be printed is heated and fixed on the object to be printed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a heater device of the present invention.

FIG. 2 is a plan view of the above heater device.

FIG. 3 is a cross-sectional view illustrating the operation of the above fixing device.

FIG. 4 is a sectional view of the image forming apparatus.

[Explanation of symbols]

 11 Page printer as an image forming apparatus 12 Paper as a material to be printed 15 Supply device 16 Transfer device 17 Fixing device 31 Toner as a material to be fixed 33 Pressing roller as a pressing means 41 Fixing heater as a heater device 44 Substrate part 45 Heat generating part Resistance heating element as a 45a Recessed part 46 Electrode part 48 Lead part 51 Overcoat layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Namiki 72 Horikawa-cho, Sachi-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Horikawa-cho Factory

Claims (7)

[Claims] 1. A substrate portion, an elongated heat generating portion provided on the substrate portion, both side portions of the heat generating portion are provided on the substrate portion along the longitudinal direction, and the heat generating portion is electrically connected to the heat generating portion. And a pair of electrode portions that are electrically connected to each other, wherein a surface portion located above the heat generating portion is projected above the surface portion located above the electrode portion. apparatus. 2. Each of the electrode parts includes a plurality of lead parts electrically connected to the heat generating part, and the lead parts are alternately arranged on both sides of the heat generating part and along the longitudinal direction of the heat generating part. 2. The heater device according to claim 1, wherein the heater devices are connected to each other through a predetermined interval. 3. The heater device according to claim 1, wherein an overcoat layer having a stronger abrasion resistance than the heat generating portion is formed at least on the upper side of the heat generating portion. 4. The substrate portion has a substantially flat plate shape, and a projecting dimension of the heat generating portion from the substrate portion is larger than a projecting dimension of each electrode portion from the substrate portion. Item 5. A heater device according to any one of items 1 to 3. 5. The heater device according to claim 1, wherein a concave portion is formed along a longitudinal direction on a surface portion located above the heat generating portion. 6. A fixing device for heating an object to be fixed, which is transferred onto the object to be printed, and fixing the object to be fixed onto the object to be printed, the heater device according to claim 1, and the heater device facing the heater device. And a pressing unit that presses the object to be printed toward the heater device side. 7. The supply device for supplying an object to be printed, a transfer device for transferring an image of the object to be fixed onto the object to be printed, and heating the object to be printed to fix the object to be fixed. An image forming apparatus comprising: a fixing device.