JPH02291579A - Fixing device - Google Patents

Abstract

PURPOSE:To apply heat by a quantity matching the thickness and outer shape of a medium and to enable the best fixation by changing the installation position of a guide roller and varying the contact area of a looped elastic sheet for a heat roller. CONSTITUTION:This fixing device is equipped with the heat roller 2 which has a heat source 1 internally, a pressure roller 5 which is pressed against the heat roller 2, the guide roller 4 which can be shifted in installation position, and the looped elastic sheet 3 which is guided by the guide roller 4 and pressure roller 5 to contact part of the peripheral surface of the heat roller 2 and sent by a driving roller 6. Further, an air cylinder 8 changes the installation position of the guide roller 4 to adjust the contact area of the looped elastic sheet 3 for the heat roller 2. Consequently, the area of a heating area is varied according to the characteristics of a recording material and fixation is performed under fixation conditions matching the recording material.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a heat pressure fixing device.

<Previous technology> Conventionally, this type of fixing device uses a heat source 1 as shown in FIG.
A pair of heating roller 2 and pressure roller 5 with built-in
The loop-shaped elastic sheet 3 was in contact with a part of the circumferential surface of the sheet and was fed by a drive roller 6. In the conventional device, the heating roller 2 is heated by the heat source 1,
Moreover, the loop-shaped elastic sheet 3 that is in contact with a part of the circumferential surface of the heating roller 2 is heated, and the recording material on which the image is formed is fed into the contact area between the heating roller 2 and the elastic sheet 3.
The unfixed image on the recording material is melted and then fixed under pressure by the pressing force of the pressure roller 5 to obtain a fixed image.

[Problem to be solved by the invention]

In the conventional fixing device described above, the contact area of the loop-shaped elastic seal l with the heating roller is constant, so even when passing a wide variety of media with different thicknesses and external shapes, it is possible to achieve only the same fixing conditions. As a result, it caused poor fixation. An object of the present invention is to provide a fixing device that solves the above problems. [Means for Solving the Problems] In order to achieve the above object, a fixing device according to the present invention includes a pair of a heating roller and a pressure roller equipped with a heat source, a guide roller whose installation position can be changed, and a pressure roller. and a loop-shaped elastic sheet that contacts a part of the circumferential surface of the heating roller by a guide roller and is fed by a cantering roller.The installation position of the guide roller is changed, and the contact area of the loop-shaped elastic sheet with the heating roller is changed. It has a mechanism for

(Example) Hereinafter, an example of the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention. In the figure, 2
1 is a heating roller with a built-in heat source 1; 5 is a pressure roller that presses against the heating roller 2; 4 is a guide roller whose installation position can be changed; 3 is a heating roller that is guided by the guide roller 4 and the pressure roller 5; It is a loop-shaped elastic sheet that is in contact with a part of its circumferential surface and is fed by a drive roller 6. Further, 8 is an air cylinder suspended vertically on the device frame 7,
The guide roller 4 is attached to the rod of the air cylinder 8, and the installation position of the guide roller 4 is changed by the air cylinder 8 to adjust the contact area (heating area) of the loop-shaped elastic sheaths 1 and 3 with respect to the heating roller 2. .

In the embodiment, the installation position of the guide roller 4 is changed as the rod length of the air cylinder 8 is shortened. Therefore, the contact area of the loop-shaped elastic sheet 3 with the heating roller 2, ie, the width of the heating area, changes. Therefore, according to the present invention, the width of the heating area is changed according to the characteristics of the recording material, and fixing is performed based on the fixing conditions suitable for the recording material. [Effects of the Invention] As explained above, the present invention can apply an amount of heat suitable for the thickness and external shape of the medium by changing the heat transfer area from the heating roller, and can perform optimal fixing.
It also has the effect of increasing the degree of freedom in component installation and making it possible to realize highly reliable equipment.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an embodiment of the present invention, and FIG. 2 is a partial perspective view showing a conventional example. 1...Heat source
2... Heating roller 3... Loop-shaped elastic sheet 4... Guide roller 5... Pressure roller 6...
・Drive roller 7...Device frame 8...Air cylinder

Claims (1)

[Claims] (1) a pair of heating roller and pressure roller equipped with a heat source;
A guide roller whose installation position can be changed, a loop-shaped elastic sheet that contacts a part of the circumferential surface of the heating roller by a pressure roller and a guide roller, and is fed by a drive roller, and a guide roller whose installation position can be changed, A fixing device comprising a mechanism for changing a contact area of a loop-shaped elastic sheet with a heating roller.