JPS61289373A - Fixing device - Google Patents

Abstract

PURPOSE:To obtain extremely superior cleaning performance, to simplify the structure of the titled device, and to facilitate maintenance by providing a cleaning member so that it is pressed against only a pressure roller. CONSTITUTION:The cleaning roller 14 is pressed against the pressure roller 13 at any time. This cleaning roller 14 consists of a rotating shaft 14A, a hollow cylindrical member 14B which is fixed to both end parts and intermediate part of the rotating shaft 14A, and the cleaning member 14C pressed in the outer periphery of the hollow cylindrical member 14B. The cleaning member 14C is a paper pipe formed by forming, for example, press board paper in a pipe shape. The surface temperature of the pressure roller 13 is lower than that of the cleaning roller 14 and 60 deg.C in a normal use state, so toner on the cleaning member (paper pipe) 14C of the cleaning roller 14 is not re-fused to be dislocated to the pressure roller 13 again.

Description

Detailed Description of the Invention [Field of Industrial Application 1] The present invention relates to a fixing device for heating and fixing a toner image onto an image support sheet such as recording paper in an image recording device such as an electrophotographic copying machine, and particularly relates to Heat roller fixing 1j consisting of a set of heating roller and pressure roller! This relates to improvements in the c position.

[Prior Art] In an image recording device such as an electrophotographic copying machine, a heating roller type fixing method is used to fix an unfixed image onto an image support sheet such as recording paper! ! Many stones are used. In this type of system, 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 heating roller, with the side on which the toner is attached facing the heating roller. , the toner is thermally fixed onto the recording paper.

Conventionally, in this type of fixing device, when the heating roller and the pressure roller are opened to press the recording paper and fix the toner image, a part of the toner is offset to the heating roller, and then the recording paper is recorded after one rotation of the heating roller. It was offset again to the rear of the paper or to the pressure roller, resulting in image stains or pressure roller stains.

For this reason, a cleaning means such as a heat-resistant pad, roller, or blade is pressed against the heating roller to remove the adhered toner.

[Problems to be Solved by the Invention] 1 However, in the conventional heat roller fixing device in which a cleaning means is pressed against such a heating roller, the surface of the heating roller reaches a high temperature of about 200°C, so it is difficult to use a heat-resistant member. It is unavoidable that the cost is high and the mechanism and structure of the pressure welding means etc. becomes complicated.
After many more copies are made, toner accumulates on the cleaning means, and the toner in contact with the heating roller melts and retransfers to the heating roller, and finally,
It was found that there was offset to the pressure roller, resulting in stains on the pressure roller or on the back side of the recording paper. This dirt on the pressure roller is a big problem in view of the recent trend toward maintenance-free printing, and a service person has no choice but to clean the roller and replace the cleaning member after thousands to hundreds of copies have been made. In order to reduce the burden on cleaning members, efforts have been made to improve toner materials and maintain the heating roller temperature within an appropriate range. As the process is repeated, it is possible to prevent a very small amount of off-ceramin which cannot be visually discerned from being transferred to the pressure roller directly from the heating roller or indirectly through the cleaning member, resulting in a clearly visible stain on the pressure roller. do not have.

Furthermore, if toner adheres to the back side of the recording paper before fixing due to toner stains inside the copying machine, it will be transferred to the pressure roller.
Staining occurs on the recording paper itself and on the back of the recording paper after the next copy.
Furthermore, if toner adhesion accumulates on the pressure roller, the adhesion force to the recording paper increases, and paper feed jams may occur due to wrapping or the like.

E Means for Solving the Problems ] The present invention effectively prevents toner stains on the heating roller and toner staining on the pressure roller in a fixing device that performs fixing using a heating roller and a pressure roller, and has a simple structure and easy maintenance. An object of the present invention is to provide a heat roller fixing device that is easy to use.

A fixing device of the present invention that achieves this object includes a rotatable heating roller and a pressure roller that rotates in pressure contact with the heating roller. The present invention is characterized in that the member is provided so as to come into pressure contact only with the pressure roller.

[Function 1] According to the present invention, by providing a cleaning member only on the side of the pressure roller that is in pressure contact with the heat roller, substantially all of the toner attached to the heat roller is transferred to the pressure roller without cleaning. A new fixing method in which the toner on the pressure roller is cleaned by a cleaning member that contacts (presses) the pressure roller, such as a cleaning member that rotates in a driven manner, and then the recording paper is passed between the two rollers and fixed. With this method, fixing can be performed without toner contamination and with a simple machine configuration.

[Example 1] One embodiment of the invention is shown in FIGS. 1-4.

Since FIG. 1 shows the main parts of a copying machine equipped with the fixing device 10 of the present invention, the recording paper fed in the direction of arrow P1 is
After the toner image is transferred in the image forming section 1, the transfer paper is conveyed to the fixing device (ilo) with the toner image attached side facing the heating roller by the conveying device 2, and is then transferred from the direction of arrow P2 through the fixing process. It is designed to be ejected outside the aircraft.

The fixing device W110 is provided with a fixing roller pair consisting of a heating roller 211 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 G2 fixed thereto being driven from drive teeth 11 (not shown) on the copying machine main body side via a gear G1, and therefore the pressure roller 13 is rotated counterclockwise. It is designed to be rotated clockwise.

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 . On the other hand, the gear G1 is connected to the paper discharge roller 15 via intermediate gears G2, G3, and G4.
It is in a meshing relationship with the tooth flLG5.

That is, the paper ejecting roller 15 rotates clockwise in the same direction as the pressure roller 13 rotates, and serves to eject the stained recording paper that has been conveyed through the pair of fixing rollers to the outside of the machine. It has become.

FIG. 2 shows a side view of the fixing vc device 10 according to the present invention, FIG. tJ%3 shows a sectional view of the fixing device, and FIG. FIG. 4 is a cross-sectional view obtained by developing a cross section perpendicular to the axis in a plane, and shows a cross-sectional view taken along the line AA in FIG. 3.

The heating roller 11 is formed into a cylindrical shape, and is made of a metal cylinder provided with a surface made of Teflon, and a heater lamp 12 is disposed inside thereof. The pressure roller 13 consists of a metal roller 13B provided with a surface portion 13A made of silicone rubber, and bearings 16 are provided at both ends of its rotating shaft 13C. A pressure bonding lever 17 is fixed to the bearing 16 from below, and a rotating support shaft 18 is attached to one end of the pressure lever 17. A coil spring 19 is provided between the end and the chassis 20. Therefore, the pressure roller 13 is moved to the heating roller 11 via the pressure lever 17 by the biasing force of the spring 19.
It is designed to be pressed against @.

One end of this pressure bonding lever 17 is rotatably supported by a rotation support shaft 18 of the chassis 20 described above, and the above-described pressure roller 13 and a cleaning roller 14 described later are rotatably supported in the middle of the lever 17. The portion near the other end is biased by a spring 19.

A cleaning roller 14 is constantly pressed against the pressure roller 13. This cleaning roller 14 is
It is composed of a rotating shaft 14A, a hollow cylindrical member 14B1 fixed to both ends and an intermediate portion of the rotating shaft 14A, and a cleaning member 14C press-fitted into the outer periphery of the hollow circular m member 14B. The cleaning member 14C is, for example, a paper tube made of pressboard paper into a pipe shape.

As clearly shown in FIGS. 2 and 4, both ends of the rotating shaft 14A of the cleaning roller 14 are rotatably supported by the press lever 17 via a bearing member 22. As shown in FIGS.

On the discharge side of both rollers 11 and 13, above the paper discharge roller 15, there is provided an idle plate 21 for guiding the recording paper.

The fixing device configured as above will be explained below.

When the copy button is pressed, the exposure section and paper feeding section are activated, and at the same time, both rollers 11 and 13 start rotating. :A light,? After passing through the processes of rr electricity and development, the image of the recording paper (transfer paper) is copied in the transfer section, and then the recording paper reaches the fixing section.

The recording paper carrying image toner on its surface is pressed between a heating roller 11 and a pressure roller 13 that are in pressure contact at a fixed position, where the recording paper is heated and melted by the heating roller 11 and fixed onto the recording paper. However, some of the toner, which cannot be visually discerned, adheres to the circumferential surface of the heating roller 11 and is transferred to the trailing edge of the recording paper and further to the pressure roller 213, where the toner on the pressure roller comes into contact with the cleaning roller that rotates as a result of the pressure. removed by 14. It should be noted that the off-sera))ner stain on the trailing edge of the recording paper cannot be visually determined and does not pose a practical problem.Thus, both rollers 11 and 13 are sufficiently cleaned by the cleaning roller 14. Further, toner, paper powder, etc. that have adhered to the heating roller 11 and the pressure roller 13 and have moved to the pressure roller 213 after the rotation starts are sufficiently cleaned by the cleaning roller 14, and then the recording paper passes between both rollers. become.

Here, the surface temperature of the pressure roller 13 is lower than that of the heating roller 211, and is 60° C. under normal use, so that the toner on the cleaning member (paper tube) 14C of the cleaning roller 14 is melted again. It will not be transferred to the pressure roller 13 again.

This α is a great advantage compared to the conventional method in which the cleaning member is pressed against the heating roller.

Cleaning member 14C of this cleaning a-714
Since the temperature of the pressure roller 13 is low, a paper tube or the like can withstand it well, and since its surface is fibrous, the molten toner penetrates deep into the fibers, making it difficult for the toner once transferred to transfer again. Even if they overlap, the outer diameter does not change significantly due to the elastic deformation of the WK tube, and the cost is low.
It has advantages such as no pollution after disposal.

Next, if a jam occurs or during long-term storage, use the second
When the operating lever 23 shown in the figure is manually operated and rotated in the direction of the arrow, the roller 23A at the tip of the operating lever 23 presses the crimp lever 17 and rotates clockwise about the rotational shaft 18. When the flow 23A engages with the four notches 17A of the crimp lever 17, it is locked. Along with this, the pressure roller 13 is separated from the heating roller 11.

Therefore, by operating the operating lever 23, the pressure can be released and the pressure roller 13 and the cleaning roller 14 can be made free to rotate. In this state, it is possible to clean the pressure roller 13 with, for example, a solvent. Moreover, since both rollers 11 and 13 are not in pressure contact during cleaning,
The toner adhering to the pressure roller 13 will not dissolve and contaminate the heating roller 11 again, making complete maintenance possible. Moreover, the cleaning roller 14 itself can be removed from the pressure lever 17 and easily replaced.
Easy to maintain.

Note that in order to bring the pressure roller 13 into contact with the heating roller 11 again, the operation lever 23 may be operated in the opposite direction to the above to release the lock.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, instead of the cleaning roller 14 described above, other rotary cleaning means or a blade-shaped toner removing means can be used. Cleaning roller 14
The heating roller 11 and the pressing roller 13 may be actively rotated using a gear or the like.
The structure of the crimping or crimping release mechanism may be changed, the biasing means for the crimping roller 13 may be formed of something other than the spring 19, and the crimping release does not necessarily have to be done manually.

[Effects of the Invention] As explained above, the fixing device according to the present invention has a structure in which the heating roller and the pressure roller are pressed against each other in a fixable state, and has extremely excellent cleaning performance, a simple structure, and easy maintenance. It's easy.

[Brief explanation of drawings]

FIG. 1 shows the fixing vcff! of the present invention! 2 and 3 show a side view and a sectional view of the fixing device. FIG. 4 is a cross-sectional view showing the relative relationship between the rollers of the fixing device. 10: Fixing device, 11: Heating roller 12:
Heater lamp, 13: Pressure roller 14: Cleaning roller. 14C: Cleaning member (paper W) 15: Paper ejection roller, 17: Pressure lever 20:
Chassis, 23: Operation lever Applicant: Konishiroku Photo Industry Co., Ltd. Q Pe - Procedural amendment March 14, 1985

Claims (1)

[Claims] In a fixing device having a rotatable heating roller and a pressure roller that rotates in pressure contact with the heating roller, a cleaning member for cleaning the heating roller and the pressure roller is brought into pressure contact only with the pressure roller. A fixing device characterized by being provided with.