JP2002108119A - Fixing device and image forming apparatus provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device which can efficiently heat a nip, has a high degree of freedom in the design of a nip shape, and prevents the generation of a crease or a curl in many kinds of recording materials to realize the improvement of a fixing characteristic, and to provide an image forming apparatus provided with the same. SOLUTION: The fixing device has an endless belt-like film 117a, a film guide 117b which is pressed by a pressure roll 118a through the film 117a to form the nip, guides the traveling of the film 117a in the nip part, and supports the film 117a, a halogen heater 119a which generates heat in response to the supply of electric power from a power source to heat the film guide 117b, and a reflector 119b which reflects the heat from the halogen heater 119a toward the surface at the opposite side of the nip of the film guide 117b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for fixing an unfixed image on a recording material by heating and pressing the recording material carrying the unfixed image while nipping and transporting the recording material between the fixing member and the pressing member. And an image forming apparatus including the fixing device.

[0002]

2. Description of the Related Art A fixing device provided in a conventional image forming apparatus will be described with reference to FIG.

FIG. 13 is a schematic sectional view showing a schematic configuration of such a fixing device.

Such a fixing device, as shown in FIG.
It has a fixing roll 517 as a hollow fixing body, a pressure roll 518 pressed against the fixing roll 517 by an urging unit (not shown), and a halogen heater (fixing heater) 519 as a heating unit. Is supplied to the halogen heater 519, so that the fixing roll 517 is heated.

In such a fixing device, the output of a sensor (not shown) for detecting the surface temperature of the fixing roll 517 is input to a temperature controller (not shown), and the temperature controller controls the halogen heater based on the output. 519 is turned ON / OFF, and the fixing roll 517 is maintained at a predetermined surface temperature.

The unfixed toner on the recording material P is
In the nip formed by the fixing roll 517 and the pressure roll 518, the recording material P is heated and pressed together with the recording material P to be permanently fixed.

[0007]

However, in such a fixing device, as shown in FIG. 13, since the entire fixing roll 517 is heated by the halogen heater 519, heat from the halogen heater 519 other than the nip is used. Are dispersed and the heating efficiency is poor, the time required to raise the nip to a desired temperature is lengthened, and it takes time to print the first one page.

Further, the conventional hollow cylindrical fixing roll 517 is difficult to form the fixing nip portion into a free shape, and is therefore required to improve wrinkles, curls, fixing properties, etc. of the recording material. Due to restrictions, it was difficult to satisfy all of the various types of recording materials.

Accordingly, the present invention can efficiently heat the nip, has a high degree of freedom in designing the nip shape, prevents wrinkles and curls from occurring on various types of recording materials, and improves the fixing property. It is an object of the present invention to provide a fixing device capable of achieving the above-mentioned condition and an image forming apparatus including the fixing device.

[0010]

According to the present invention, an object of the present invention is to provide a recording apparatus which comprises a fixing member and a pressing member which rotate by pressing against each other, and a heating means for heating the fixing member, and which carries an unfixed image. In a fixing device for fixing the unfixed image to the recording material by heating and pressing while nipping and conveying the material between the fixing member and the pressing member, the fixing member includes an endless belt-shaped film member, and the film member. A guide member for forming a nip by being pressed against the pressurizing body through the nip portion, guiding the film member at the nip portion, and supporting the film member. The first invention has a heating element that generates heat by receiving supply of electric power and heats the guide member, and a reflection unit that reflects heat from the heating element toward a surface on the anti-nip side of the guide member. Yo It is achieved.

According to the present application, the above object is also achieved by the second invention in the first invention, wherein the guide member has a planar shape on the surface forming the nip.

Further, according to the present application, the above object is achieved in the first invention or the second invention, wherein the guide member has a third shape in which the surface forming the nip has a crown shape in the axial direction of the fixing member. It is also achieved by the invention.

Further, according to the present application, the above object is achieved in any one of the first to third inventions in that the guide member has a uniform thickness in a direction perpendicular to a surface forming the nip. This is also achieved by the fourth aspect of the invention.

Further, according to the present application, the above object is achieved in any one of the first to third inventions, wherein the guide member has a thickness in a direction perpendicular to a surface forming the nip, and the thickness of the guide member is set at the axis of the fixing member. The invention is also achieved by the fifth invention in which the end side in the direction is formed to be thinner than the center side.

Further, according to the present application, the above object is achieved in any one of the first to fifth inventions, wherein the guide member is formed of aluminum or copper having high thermal conductivity or an alloy using these. This is also achieved by the sixth invention.

Further, according to the present application, the above object is achieved in any one of the first to sixth inventions, wherein the guide member has a black surface on the opposite side of the nip so as to absorb heat from the heat generating means. This is also achieved by the seventh invention in which a heat-resistant coating is applied.

According to the present application, the above object is achieved by any one of the first to seventh inventions, wherein the reflecting means comprises:
A first reflector disposed close to the heating element, and a second reflector disposed at a position farther than the first reflection plate with respect to the heating element, the first reflection plate and the second The present invention is also achieved by the eighth invention in which the two reflecting plates are formed with a reflecting surface so as to concentrate heat from the heating element on a surface on the side opposite to the nip of the guide member.

Further, according to the present application, the above object is an image forming apparatus for recording an image formed by a series of image forming processes on a recording material, wherein the image forming apparatus is any one of the first to eighth inventions. The present invention is also attained by the ninth invention in which the fixing device is provided.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described.

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an example of an image forming apparatus according to the present embodiment, and FIG.
FIG. 2 is a block diagram illustrating a configuration of an electric circuit of a control system of the image forming apparatus.

In such an image forming apparatus, as shown in FIG. 1, an electric signal which is code data input from a host computer (not shown) or the like is After being developed into an image and stored in the memory inside the video controller, it is returned to the engine unit 102 as a video signal.
Each element of the engine unit 102 is an engine controller 1
The video signal is exchanged with the controller unit 100 via the engine controller 105. A video signal input to a video interface (not shown) of the engine controller 105 is sent to a laser driver 106, where ON / OFF of the semiconductor laser 107 is controlled.

The laser light 110 emitted from the semiconductor laser 107 is deflected by the polygon mirror 108 to become scanning light in the longitudinal direction of the photosensitive drum 112, and is projected on the photosensitive drum 112 via the mirror 109.

The photosensitive drum 112 rotates in the direction of the arrow,
After being temporarily charged by the primary charger 111, the photosensitive drum 112 is exposed to light according to ON / OFF of the laser beam from the semiconductor laser 107, and an electrostatic latent image is formed on the surface of the photosensitive drum 112.

The electrostatic latent image is supplied with colored charged particles (hereinafter, referred to as toner) by a developing device 113, and after a visible image is obtained, the latent image is fed from a sheet feeding cassette 120 by a transfer charger 114. The visible image is transferred to the recording material P taken out one by one by the roll 121. on the other hand,
The transfer residual toner is wiped off from the surface of the photosensitive drum 112 by the cleaning device 115, and the photosensitive drum 112 prepares for the next image forming process.

The recording material P on which the unfixed toner image is placed is passed through a fixing device 116 as a fixing device, and after a permanent fixed image is obtained, the recording material P is discharged out of the apparatus as a final print in the direction of the arrow in the figure. Is done. The arrows in the drawing indicate the feeding trajectory of the recording material P taken out of the sheet feeding cassette 120 and conveyed.

Here, the fixing device 116 will be described in detail.

FIG. 3 is a cross-sectional view showing a schematic configuration of the fixing device 116 of the present embodiment, and FIG. 4 is a vertical cross-sectional view taken along the line AA ′.

As shown in FIG. 3, the fixing device 116 includes a film 117a serving as a film member, a pressure roll 118a serving as a pressing member, a film guide 117b serving as a guide member, a halogen heater 119a serving as a heating member, and a reflection member. And a reflector 119b as a means.

In the fixing device 116, electric power from a power supply (not shown) is supplied to a filament heating element (not shown) of the halogen heater 119a through connectors 119c on the left and right of the halogen heater 119a. When power is supplied to the filament heating element, the filament heating element generates heat. The heat radiated from the filament heating element is radiated all around the halogen heater 119a.

The heat radiated from the halogen heater 119a is reflected by a reflecting plate 119b attached along a part of the peripheral surface of the halogen heater 119a and concentrated on the film guide 117b, and the surface of the film guide 117b on the opposite nip side ( (Hereinafter referred to as the back surface). The heat that warms the back surface of the film guide 117b is applied to the film guide 117b.
b, and the entire film guide 117b is heated at the same temperature.

The heat transmitted to the film guide 117b is
It is transmitted to the film 117a and the film guide 117b
Then, the fixing nip formed by the pressure roll 118a is heated.

The heat from the film 117a in the fixing nip portion is transmitted to the recording material P sandwiched between the fixing nip portions, and the recording material P and the unfixed toner on the recording material P are warmed to heat the unfixed toner. Used to melt Further, the toner is pressed by the pressure roll 118a from the opposite side of the fixing nip portion, and the toner is thermally and pressure-fixed to the recording material P. Pressure roll 118
a is rotatably supported by the main body of the fixing device 116 by a bearing 118b, is rotated at a desired speed by transmitting a rotational driving force via a driving gear 118c, and rotates the film 117a by rotation. The recording material P is conveyed by the rotation of the pressure roll 118a, and the unfixed toner is heat-pressure-fixed in the fixing nip portion, and is discharged from the fixing device 116.

In order to adjust the fixing temperature, a temperature sensor (not shown) is attached near the film guide 117b, and the temperature information of the fixing nip portion is taken in by a CPU (not shown). The current flowing through the halogen heater 119a is adjusted according to the temperature information to control the temperature of the fixing nip.

The nip side surface of the film guide 117b has a crown shape in the longitudinal direction, and has a recording material having a width sufficiently smaller than the longitudinal length of the film guide 117b (for example, the longitudinal direction of the film guide 117b). If the length is 297 mm in length of A4 size, wrinkles in the case where the width of the recording material is 210 mm in width of A4 size) are prevented.

The film guide 117b has a stay 117
c, and the stay 117c is connected to the pressing spring 117.
By pressing against the pressure roll 118a with d,
The nip surface of the film guide 117b is
The pressure is applied to the pressure roll 118a via the a.

(Second Embodiment) Next, a second embodiment of the present invention will be described. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 5 is a schematic sectional view showing a schematic configuration of the fixing device according to the present embodiment, and FIG. 6 is a longitudinal sectional view thereof.

In this embodiment, as shown in FIGS. 5 and 6, a film guide 217b as a guide member is provided instead of the film guide 117b.
7b has a flat nip surface, and a recording material having the same width as the longitudinal direction of the film guide 217b (for example, the longitudinal length of the film guide is A4 size width + 10 mm)
(220mm) and the recording material is A4 size vertical feed and width is 2
Since pressure is applied evenly when paper is passed (in the case of 10 mm), the fixability of the central portion and the end portion in the longitudinal direction can be made uniform, and curling of the recording material can be reduced.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In addition, about the structure similar to 1st Embodiment or 2nd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

FIG. 7 is a schematic sectional view showing a schematic configuration of the fixing device according to the present embodiment, and FIG. 8 is a longitudinal sectional view thereof.

In this embodiment, as shown in FIGS. 7 and 8, in addition to the reflector 119b, a halogen heater 119a is provided.
Is provided in contact with the first reflector 219b, and the heat radiated from the halogen heater 119a is applied to the first reflector 219b and the peripheral surface of the halogen heater 119a at a position farther from the first reflector 219b. The light is reflected by the reflecting plate (second reflecting plate) 119b attached thereto, and is concentrated on the back surface of the film guide 217b.
Warm 17b.

As described above, by doubling the reflectors, the heat of the second reflector 119b being heated and escaping therefrom is reduced, and the amount of heat transmitted from the halogen heater 119a to the film guide 217b is increased. Increase heat generation efficiency.

In this embodiment, the film guide 21
7b is controlled at the same fixing temperature as that of the second embodiment, the first reflection plate 21 for the halogen heater 119a is controlled.
By mounting the reflector 9b and using a double reflector, the amount of heat generated by the halogen heater 119a can be reduced as compared with the case where only the reflector 119b is used as in the second embodiment, so that the power consumption of the halogen heater 119a is also reduced. be able to.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. The same components as those in the first to third embodiments are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 9 is a schematic sectional view showing a schematic configuration of a fixing device according to the present embodiment, and FIG. 10 is a longitudinal sectional view thereof.

In this embodiment, as shown in FIGS. 9 and 10, a film guide 317b as a guide member is provided in place of the film guide 117b of the first embodiment.
The nip surface of the film guide 317b has a crown shape in the longitudinal direction, and has a width sufficiently smaller than the length of the film guide 317b in the longitudinal direction (for example, the longitudinal length of the film guide 317b is 297 m in length of A4 size).
m, wrinkles when the width of the recording material is A4 size and 210 mm in width) can be prevented.

In the first embodiment, the film guide 11
7b is non-uniform in the longitudinal direction, and the heat resistance from the opposite nip surface to the nip surface of the film guide 117b is non-uniform in the longitudinal direction. And the temperature is high because the end is thinner than the center.

In this embodiment, the film guide 317b
The thickness of the nip is made constant, the thermal resistance of the end portion and the central portion are made uniform, and the temperature of the nip portion in the longitudinal direction becomes uniform.
Thereby, the fixing property of the center part and the end part can be made uniform.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. The same components as those in the first to fourth embodiments are denoted by the same reference numerals, and description thereof is omitted.

FIG. 11 is a schematic sectional view showing a schematic configuration of a fixing device according to the present embodiment, and FIG.
-B 'It is a longitudinal cross-sectional view.

In this embodiment, as shown in FIGS. 11 and 12, a film guide 417b as a guide member is provided in place of the film guide 117b of the first embodiment, and the nip surface of the film guide 417b is long. The surface (anti-nip surface) on the side of the halogen heater 119a has a crown shape. That is, the film guide 417b has a structure in which the thickness from the opposite nip surface to the nip surface is thicker at the center in the longitudinal direction and thinner at the ends. As a result, the end portion is connected to the film guide 417.
Since there is escape of heat to portions other than b, the temperature of the fixing nip portion is lower than that of the central portion. By making the end portion of the film guide 417b thinner, it is possible to prevent the temperature of the nip surface at the end portion from lowering by lowering the thermal resistance than the central portion.

[0053]

As described above, according to the first aspect of the present invention, the heat from the heating element is concentrated and reflected toward the surface on the side opposite to the nip of the guide member by the reflection means, so that the guide is provided. Because the member is heated and the nip is heated, the nip can be heated efficiently,
Further, the degree of freedom in designing the shape of the nip is high, and it is possible to prevent wrinkles and curls from occurring in various types of recording materials and to improve the fixing property.

According to the second invention of the present application,
The nip side surface of the guide member has a planar shape, and heat from the heating element is concentrated and reflected toward the opposite nip side surface of the guide member by the reflection means, so that the guide member is heated and the nip is heated. Because it is heated
The nip can be efficiently heated, the nip shape has a high degree of design freedom, the nip pressure is made uniform, and wrinkling and curling of various types of recording materials are prevented and the fixing property is improved. Can be improved.

Further, according to the third invention of the present application, the nip side surface of the guide member has a crown shape in the axial direction of the fixing member, and the heat from the heat generating member is transferred by the reflecting means. The nip is heated because the guide member is heated by concentrating and reflecting toward the surface on the opposite side of the nip, so that the nip can be heated efficiently and the design of the nip shape It has a high degree of freedom, and can prevent wrinkles and curls from occurring on various types of recording materials, and can effectively improve fixability.

According to the fourth invention of the present application,
The thickness of the nip side surface of the guide member in the perpendicular direction is uniform, and the heat from the heating element is concentrated and reflected toward the non-nip side surface of the guide member by the reflection means, thereby heating the guide member. The nip is heated so that the nip can be efficiently and uniformly heated, and the nip shape has a high degree of freedom in design, preventing wrinkles and curling of various types of recording materials. In addition, the fixing property can be improved.

Further, according to the fifth aspect of the present invention, the thickness of the guide member in the direction perpendicular to the nip-side surface is formed so that the end portion in the axial direction of the fixing member is thinner than the center portion. In addition, since the heat from the heating element is concentrated and reflected toward the surface of the guide member on the side opposite to the nip by the reflection means, the guide member is heated and the nip is heated. The nip can be efficiently heated by preventing the temperature drop on the side, and the nip shape has a high degree of freedom in design, preventing wrinkling and curling of various types of recording materials and improving the fixing property. Can be achieved.

According to the sixth aspect of the present invention,
The guide member is made of aluminum or copper having high thermal conductivity or an alloy using them, and heat from the heating element is concentrated and reflected toward the anti-nip side surface of the guide member by the reflection means. Since the guide member is heated to heat the nip, the guide member is effectively heated, and the nip can be efficiently heated. It is possible to prevent wrinkles and curls from occurring in various types of recording materials and to improve the fixing property.

Further, according to the seventh aspect of the present invention, the surface of the guide member on the side opposite to the nip is coated with black, and the heat from the heat generating element is reflected by the reflection means. Since the nip is heated by heating the guide member concentratedly reflected toward the surface, the guide member is effectively heated, and the nip can be efficiently heated, and The design flexibility of the nip shape is high, and it is possible to prevent wrinkles and curls from occurring in various types of recording materials and to improve the fixing property.

According to the eighth invention of the present application,
Since the heat from the heating element is concentrated and reflected toward the surface on the opposite nip side of the guide member by the first reflector and the second reflector, the guide member is heated and the nip is heated. The guide member is effectively heated, the nip can be heated efficiently, and the nip shape has a high degree of freedom in design, preventing wrinkling and curling of various types of recording materials and fixing property. Improvement can be achieved.

Further, according to the ninth invention of the present application, the heat from the heating element is concentrated and reflected toward the surface on the side opposite to the nip of the guide member by the reflection means, so that the guide member is heated and the nip is heated. Is to be heated,
The nip can be efficiently heated, the degree of freedom in designing the shape of the nip is high, and wrinkling and curling of various types of recording materials can be prevented and the fixing property can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a fixing device provided in the image forming apparatus of FIG.

FIG. 2 is a vertical sectional view taken along line AA ′ of the fixing device of FIG. 1;

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a fixing device according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of the fixing device of FIG.

FIG. 5 is a cross-sectional view illustrating a schematic configuration of a fixing device according to a third embodiment of the present invention.

6 is a vertical sectional view of the fixing device shown in FIG.

FIG. 7 is a cross-sectional view illustrating a schematic configuration of a fixing device according to a fourth embodiment of the present invention.

8 is a longitudinal sectional view of the fixing device of FIG.

FIG. 9 is a cross-sectional view illustrating a schematic configuration of a fixing device according to a fifth embodiment of the present invention.

10 is a vertical sectional view of the fixing device shown in FIG.

FIG. 11 is a cross-sectional view illustrating a schematic configuration of a conventional fixing device.

12 is a block diagram illustrating a configuration of an electric circuit of a control system of the image forming apparatus in FIG.

FIG. 13 is a schematic sectional view illustrating a schematic configuration of the image forming apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

 116 Fixing Unit (Fixing Device) 117a Film (Film Member) 117b Film Guide (Guide Member) 118a Pressure Roller (Pressure Body) 119a Halogen Heater (Heat Heating Element) 119b Reflector (Second Reflector) 217b Film Guide (Film) Member) 219b First reflector (reflector) 317b Film guide (guide member) 417b Film guide (guide member) P Recording material

Claims (9)

[Claims] An image forming apparatus comprising: a fixing member and a pressing member that rotate in pressure contact with each other; and a heating unit that heats the fixing member. The recording material that carries an unfixed image is nipped and conveyed by the fixing member and the pressing member. In a fixing device for fixing the unfixed image on the recording material by heating and pressing while the fixing member is in the form of an endless belt-shaped film member, the nip is pressed by the pressing member through the film member. And a guide member that guides the film member to travel and supports the film member at the nip portion, and the heating means generates heat when supplied with power from a power supply to heat the guide member. A fixing device comprising: a heating element; and a reflection unit configured to reflect heat from the heating element toward a surface on a side opposite to the nip of the guide member. 2. The fixing device according to claim 1, wherein a surface of the guide member forming a nip has a planar shape. 3. A fixing device according to claim 1, wherein the guide member has a nip forming surface having a crown shape in the axial direction of the fixing member. 4. The fixing device according to claim 1, wherein the guide member is formed to have a uniform thickness in a direction perpendicular to a surface forming the nip. . 5. The guide member according to claim 1, wherein a thickness in a direction perpendicular to a surface forming the nip is smaller at an end portion side in an axial direction of the fixing body than at a center portion side. The fixing device according to claim 3. 6. The fixing device according to claim 1, wherein the guide member is formed of aluminum or copper having high thermal conductivity or an alloy using them. 7. The guide member according to claim 1, wherein a black heat-resistant coating is applied to a surface opposite to the nip so as to absorb heat from the heat generating means. Fixing device. 8. A reflection means, comprising: a first reflection plate disposed in contact with or close to the heating element; and a second reflection plate disposed farther from the heating element than the first reflection plate. And
8. The reflection surface of any one of claims 1 to 7, wherein the first reflection plate and the second reflection plate are formed such that heat from the heating element is concentrated on a surface of the guide member on the side opposite to the nip. Item 6. The fixing device according to item 1. 9. An image forming apparatus for recording an image formed by a series of image forming processes on a recording material, comprising: the fixing device according to claim 1. Description: Image forming apparatus.