JPS6218583A - Fixing device - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to facilitate the maintenance of a heater lamp by giving to a drive member such a shape as to close and cover the opening end of a heating roller and fixing the shape to one end part of the heating roller. CONSTITUTION:The drive member G1 is fixed to the end part of the opening of the heating roller 11 with a key way, a screw, etc., and abuts on the end surface of an insulating bearing member 19 to position in a thrust direction. In the center of the drive member G1 a hole slightly larger than a maximum diameter of the heater lamp 12 is made in order to penetrate the heater lamp 12. When the heater lamp 12 is built in the heating roller 11, the drive member G1 in such a shape closes and covers almost the end part of the opening of the straight pipe shaped heating roller 11, and therefore the leakage of heat and light caused by the heater lamp 12 in the heating roller 11 can be almost prevented. Moreover the heat is absorbed by the cover closing part of the drive member G1, whereby the temperature of the member G1 rises sufficiently and acts as to compensate the hat spread out of the G1 to hold the uniform temperature distribution of the heating roller.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fixing device for heating and fixing a toner image onto an image support sheet such as a recording paper in an image recording device such as an electrophotographic copying machine, and more particularly to a heat roller fixing device comprising a set of a heating roller and a pressure roller. This is related to the improvement of.

[Conventional technology]

2. Description of the Related Art In image recording apparatuses such as electrophotographic copying machines, a heat roller fixing device is often used to fix an unfixed image onto an image support sheet such as a recording paper. In this type of method, a recording paper supporting an unfixed toner image is conveyed between a heating roller equipped with a heat source and a pressure roller that is in pressure contact with the roller, and the toner is thermally fixed onto the recording paper. be. Compared to the conventional hot plate type fixing device, this heat roller fixing device uses two rollers, a heating roller and a pressure roller, to press the recording paper (transfer material) and then transport it for fixing, so it conducts heat. It has excellent characteristics, and not only allows the set temperature of the heating roller to be lowered, but also allows for high-speed conveyance. The heating roller of a conventional heating roller fixing device has flanges formed at both ends thereof. In FIG. 5, 1 is a heating roller with a built-in heater lamp 2, 3 is a pressure roller, and a hollow cylindrical portion IC of the heating roller 1 has flange portions IA with holes at both ends thereof. 1B is fixed. The flange portions IA and IB are connected to the lees receivers 5A fixed to the side plates 4A and 4B, respectively.
, 5B, and a driving member such as a gear 6 is fixed to the end of one flange portion IB. A heater lamp 2 passes through the center holes of the flange portions IA, IB and the center of the heating roller 1, and both ends thereof are supported by conductive holding members 7A, 7B. Another structure of the heating roller is disclosed in Japanese Patent Application Laid-Open No. 56-11317.
There is a configuration shown in Publication No. 9. As shown in the cross-sectional view of Fig. 6, in order to reduce the cost of the heating roller, the flange parts IA and IB of the heating roller 1 are eliminated and a straight pipe is used, resulting in a simple structure. It is something.

[Problems to be solved by the invention]

In a conventional fixing device, in the case of a heating roller having a flange portion as shown in Fig. 5, the heat and light of the heater lamp leak through the hole at the end of the flange portion, and the heat is dissipated to the outside. Cheap. For this reason, it takes a long time to raise the heating roller temperature to the set temperature after the heater lamp is turned on, that is, a long start-up time, which is not desirable for the user. In addition, external light leakage occurs, and this light leakage may impede the copying process. Furthermore, on the drive member side, the temperature of the heating roller is rapidly reduced due to the dissipation of heat from the gear 6, making it impossible to obtain a uniform temperature over the entire length of the heating roller. Furthermore, when the heating roller 21 is made into a straight pipe as shown in Fig. 6, the above-mentioned drawback is particularly noticeable, and since the openings at both ends of the pipe are wide, the heat inside the heating roller and the light from the heater lamp are transmitted to the outside through these openings. The light easily dissipates, prolongs the rising time, has an adverse effect on the photoreceptor, and causes discomfort to the user if it leaks to the outside. Furthermore, as mentioned above, since the heat inside the heating roller easily escapes to the outside, the temperature around the fixing device, especially on both sides, increases.
The casing material needs to be heat resistant, which has the disadvantage of increasing costs.

[Means to solve the problem]

The present invention provides a fixing device that solves the above-mentioned drawbacks of the heating roller, in which the heating σ-ra is configured with a small and simple structure, and furthermore, the temperature decreases on the heating roller drive side. It is an object of the present invention to provide a fixing device that can always have a uniform temperature distribution by eliminating the heat dissipation. A fixing device of the present invention that achieves this object is a fixing device having a heating roller that has a built-in heating source and is rotatable by a driving member, and a pressure roller that is in pressure contact with the heating roller. The heating roller is characterized in that the open end of the roller is shaped to be closed and can be fixed to one end of the heating roller.

【Example】

An embodiment of the present invention is shown in FIGS. 1 to 4. FIG. 1 shows the main parts of a copying machine equipped with a fixing device 10 of the present invention, and the recording paper fed from the direction indicated by the arrow P1 is
After the toner image is transferred in the image forming section 1 and transported to the fixing device 10 by the transport device 2, it is discharged from the machine in the direction of arrow P2 after undergoing a fixing process. The fixing device 10 is provided with a fixing roller pair consisting of a heating roller 11 having a built-in heater lamp and a pressure roller 13 that is elastically pressed against the heating roller 11 and driven by its rotation. The heating roller 11 is rotated counterclockwise by a gear G1 fixed thereon being driven from a drive gear (not shown) on the copying body side via an intermediate gear GO, and therefore the pressure roller 13 is rotated counterclockwise. It is designed to be rotated in the direction. On the other hand, a cleaning roller 14 is also provided in elastic pressure contact with the pressure roller 13 and rotates counterclockwise in accordance with the pressure roller 13 . Further, the gear G1 is connected to the paper ejection roller 1 via intermediate gears G 2 , G 3 , and G 4 .
It is in a relationship that meshes with gear G5 of No. 5. That is, the paper ejection roller 15 rotates clockwise in the same direction as the pressure roller 13 rotates (so that it serves to eject the recording paper that has been conveyed through the pair of fixing rollers to the outside of the machine). FIG. 2 shows a cross-sectional view of the fixing device 10 according to the present invention. FIG. The heating roller 11 is formed in a cylindrical shape and is made of Teflon t.
It consists of a metal cylinder provided with a surface portion, and a heater lamp 12 is arranged inside. FIG. 4 is an exploded perspective view showing a part of the fixing device including the heating roller 11. FIG. Commonly used heating roller 11
The core metal is an aluminum alloy or carbon steel pipe with a thickness of about 0.8 to 3 m+n, and silicone rubber, PTFE (Teflon), or PFA (tetrafluoroethylene-perfluoroethylene), which has good toner release properties, is used as a core metal. It is coated with alkyl vinyl ether copolymer). Both ends of this heating roller 11 are provided with heat insulating bearing members 19.
It is pivotally supported by the chassis 20 via. Furthermore, a driving member 61 for driving and rotating the heating roller 11 is provided at the end of the heating roller 11. The driving member G1 is usually composed of a gear or a sprocket, and is rotated by receiving the driving force from the motor through other gears, a chain, a sprocket, or the like. The drive member G1 is fixed to the open end of the heating roller 11 using a keyway, a set screw, etc., and is brought into contact with the end surface of the heat insulating bearing member 19 for positioning in the thrust direction. . A hole slightly larger than the maximum diameter of the heater lamp 12 is formed in the center of the driving member G1 so that the heater lamp 12 passes through the hole. The drive member G1 having such a shape closes most of the end opening of the straight pipe-shaped heating roller 11 when the heater lamp 12 is built into the heating row 211, so that the heater lamp inside the heating roller 11 is closed. Fever caused by 12. The leakage of the emitted light to the outside is almost prevented, and the closed lid portion of the drive member G1 absorbs the heat, so that the temperature of G1 rises sufficiently and works to compensate for the heat dissipated from G1. , uniform temperature distribution of the heating roller is maintained. Also,
The heater lamp 12 can be easily replaced with the driving member G1 fixed. Note that the driving member G1
is an iron-based sintered alloy, a steel material that has been cut or plastically worked, or a heat-resistant resin material that has been molded. The pressure roller 13 is a metal roller with a surface made of silicone rubber, and both ends of the pressure roller 13 are provided with a swingable pressure lever 1.
6 is supported. At one end of the crimp lever 16 is a rotary support shaft 17, m! A coil spring 18 is provided between the end and the chassis 20. Therefore, the pressure roller 13 is pushed against the pressure lever 1 by the biasing force of the spring 18.
Pressure #7- is always applied to the heating roller 11 side via G. Further, a cleaning roller 14 that comes into pressure contact with the hem crimping row 213 is rotatably supported in an intermediate portion of the crimping lever 16 . Furthermore, on the discharge side of both rollers 11 and 13, paper ejection roller 1
A guide plate 21 for guiding the recording paper is arranged above the recording paper 5. Although the present invention has been exemplified above, the shapes of the heating roller without flanges and the driving member described above can be further modified based on the technical concept of the present invention.

【Effect of the invention】

As explained above, the heating roller of the fixing device according to the present invention and the drive member connected thereto have a simple structure, have a small number of parts, are inexpensive, and the built-in heater lamp is easy to maintain. be. Moreover, since the heat and light inside the heating roller are less likely to leak to the outside, there is a possibility of poor fixing due to a drop in temperature at the end of the heating roller.
It is also possible to prevent an increase in the temperature around the fixing device, and it is possible to perform efficient fixing.

[Brief explanation of the drawing]

#S1 is a sectional view of the main parts of a copying machine equipped with the fixing device of the present invention. FIGS. 2 and 3 show a side view and a sectional view of the fixing device. FIG. 4 is a planar cross-sectional view showing the relative relationship between the rollers of the fixing device. 5 and 6 are cross-sectional views of a conventional fixing device. 10: Fixing device, 11: Heating roller 12:
Heater lamp, 13: Pressure roller 14: Cleaning roller. 15: Paper ejection roller, 17: Pressure lever 19:
Heat insulating bearing member, 20: Chassis G1: Drive member Applicant: Konishiroku Photo Industry Co., Ltd. Figure 5 Figure 6

Claims (2)

[Claims] (1) In a fixing device having a heating roller that has a built-in heating source and is rotatable by a driving member, and a pressure roller that is in pressure contact with the heating roller, the driving member has a shape that closes an open end of the heating roller. 1. A fixing device, characterized in that the fixing device is fixed to one end of the heating roller. (2) The fixing device according to claim 1, wherein the heating roller is formed of a hollow cylinder without a flange.