JPH0473785A - Electrophotographic printing device - Google Patents

Abstract

PURPOSE:To obtain an image whose fixation is excellent by providing a pressurizing force variable setting means for controlling the pressurizing force of the pressure roller of a fixing roller pair which press-contacts, follows and rotates with a heating roller. CONSTITUTION:A thickness detecting means 1 for detecting the thickness of a recording body is arranged on the way of a carrying path 6a just after the recording paper is supplied. Then, the control of the temperature/pressure of a fixing device 8 is performed by a fixing temperature variable control means 2 and the pressurizing force variable control means 4 in accordance with a signal corresponding to the thickness of the recording body which is detected by the means 1. The fixing device 8 is provided with the heating roller 18 equipped with a heating means 3 and the pressure roller 19, and the bearing 20 of the roller 19 is guided in the radial direction of the roller 18 and pressed by a spring 21 attached between a pressurizing force variable mechanism 5 and the bearing 20, so that the roller 19 is pressed to the roller 18. The mechanism 5 receives a signal from the means 4 and the leading edge thereof is displaced by a screwing and feeding mechanism, then the pressurizing force of the roller 19 is changed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic printing device.

[Conventional technology]

Conventionally, in this type of electrophotographic printing apparatus, the pressing force of the pressure roller and the temperature of the heating roller of the roller pair that nip and convey the unfixed image recording medium and fix the image on the recording medium are initially set at The set pressing force and fixing temperature remain constant, and there is no means to change the pressing force of the pressure roller or the fixing temperature of the heating roller, and the thickness of the image recording medium is detected. He didn't even have the means.

[Problem to be solved by the invention]

The above-mentioned conventional electrophotographic printing device does not have a means to change the pressure applied to the fixing device or a means to change the fixing temperature. In the case of recording materials that require high pressure or high fusing temperature, the pressure roller pressure and fusing temperature are fixed at the initial settings, so the fusing performance is significantly worse than that of plain paper. There is a drawback that it becomes difficult.

Additionally, if the pressure and fixing temperature are set from the beginning to improve the fixing performance on thick paper, envelopes, etc., wrinkles and curls may occur if the recording material is thin paper. There are drawbacks.

[Means to solve the problem]

In the present invention, a recording medium is fed and conveyed, an unfixed image is formed on the recording medium through an image forming process, and then the unfixed image recording medium is passed through a fixing device to be transferred onto the recording medium. In an electrophotographic printing device that discharges the recording medium after fixing an unfixed image, a thickness detection means for detecting the thickness of the recording body, and a thickness of the recording body detected by the detection means. a fixing temperature control means for changing the temperature of one heating roller of the pair of fixing rollers of the fixing device according to the heating roller; and a pressing force of the other pressure roller of the pair of fixing rollers that is in pressure contact with the heating roller and rotated as a result of the rotation. The pressurizing force variable setting means is provided to control the pressurizing force.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic block diagram of one embodiment of the present invention. The fixing temperature variable control means 2 and the pressure variable control means 4, which have received the signal corresponding to the thickness of the image recording medium detected by the thickness detection means 1, adjust the heating means 3 and the pressure variable control means 4 according to the received signals. Send a signal to mechanism 5. The fixing temperature and pressure are controlled according to the thickness of the image recording medium.

FIG. 2 is a schematic cross-sectional view of an electrophotographic printing device according to an embodiment of the present invention. A paper feed cassette 16 is attached to the supply side of the recording medium (not shown) of the main body 15 of the electrophotographic printing apparatus. Inside the printer main body 15, a recording medium conveyance path 6a is disposed following the paper feeding cassette 16, and a conveyance path 6b is disposed following it. Next is a part called the image forming process, in which a photoreceptor drum 9 is installed, and a cleaner 10. Erase lamp 11. Charger 12, exposure device 1
3. Developing device 14. A transfer charger 15 is placed in contact with or in the vicinity, and an image is formed in this portion to create an unfixed image on the recording medium. A conveyance path 6C is provided following this image forming process portion. The recording medium is conveyed in the direction of arrow A, passes through the fixing device 8, and is then discharged through the conveyance FIII 6d.

In this embodiment, thickness detection means 1 for detecting the thickness of the recording medium is used.
is arranged in the middle of the conveyance path 6a immediately after the recording medium is fed, and the fixing temperature variable control means shown in FIG. 2.
The temperature/pressure of the fixing device 8 is controlled by the pressure variable control means 4.

It is also conceivable to arrange the thickness detection means 7 not in the middle of the conveyance path 6a but on the operator panel of the printing device, so that the operator himself can input the thickness.

FIG. 3 is a sectional view of the fixing device 8 shown in FIG. 2. The fixing device 8 is provided with a heating roller 18 having a heating means 3 and a pressure roller 19. A bearing 20 of the pressure roller 19 is guided in the radial direction of the heating roller 18, and is installed between the heating roller 18 and the pressure variable mechanism 5. The pressure roller 19 is pressed against the heating roller 18 by the spring 21 . The pressure variable mechanism 5 receives a signal from the pressure variable control means 4 and changes the pressure of the pressure roller 19 by displacing its tip using a feeding mechanism or the like.

〔Effect of the invention〕

As explained above, the present invention includes a thickness detection means for detecting the thickness of an image recording medium, and a fixing temperature for changing the fixing temperature of a heating roller according to the thickness of the recording medium detected by the detection means. By providing a control means and a pressure variable setting means for controlling the pressure of the pressure roller, the pressure and fixing temperature can be variably set according to the thickness of the recording medium to be printed, and the The effect is that images with good fixing properties can always be obtained regardless of the thickness of the body.

Furthermore, when the recording medium is thin paper, an image with good fixing properties can be obtained even at a high printing process speed, which has the effect of enabling high-speed printing.

[Brief explanation of the drawing]

1 and 2 are a schematic block diagram and a sectional view of an embodiment of the present invention, respectively, and FIG. 3 is a sectional view of the fixing device 8 shown in FIG. 2. DESCRIPTION OF SYMBOLS 1... Thickness detection means, 2... Fixing temperature variable control means, 3... Heating means, 4... Pressure force variable control means, 5
... Pressure force variable mechanism, 6a, b, c... Conveyance path, 8
. . . Fixing device, 9 . . . Photosensitive drum, 10 .・Electrophotographic printing device body, 16 ・Paper feeding cassette, 1
8... Heating roller, 19... Pressure roller.

Claims (1)

[Claims] After feeding and transporting a recording medium and forming an unfixed image on the recording medium through an image forming process, the unfixed image recording medium is passed through a fixing device to form an unfixed image on the recording medium. In an electrophotographic printing device that discharges the recording body after fixing, a thickness detection means for detecting the thickness of the recording body;
a fixing temperature control means for changing the temperature of one heating roller of a pair of fixing rollers of the fixing device according to the thickness of the recording medium detected by the detection means; 1. An electrophotographic printing apparatus comprising variable pressure setting means for controlling the pressure of the other pressure roller of a pair of fixing rollers.