JPS6383780A - Electronicphotographic device - Google Patents

Abstract

PURPOSE:To simplify operation by providing a pressuring means to contact mutually a thermal roller pair with pressure at a prescribed position, interlocking with a closing action by a main body and pressurizing a supporting means up to the prescribed position by the main body. CONSTITUTION:A pressurizing projection 42 to pressure heating roller frame 20 in a pressure roller 11b direction is composed of a part of a main body frame 40. A heating roller frame 20 to receive a force in the pressure roller 11b direction by the pressurizing projection 42 is pressured in the pressure roller 11b direction and positioned while a main body is closed. The pressure roller 11b is pressed downward by the action of the heating roller 11a interlocked with the action of a supporting means, a pressure spring 31 is stretched and roller pairs 11a, 11b are mutually contacted with pressure. When a main body 40 is raised due to paper jamming, the pressuring projection 42 is moved upward, the force to pressure is eliminated, the heating roller frame 20 can be moved in the direction to outdistance the roller pairs 11a, 11b and the paper jamming of the pressure contacting part can be easily processed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic apparatus such as an electrophotographic copying machine or printer, and more particularly to an electrophotographic apparatus equipped with a heating roller type fixing device. .

Conventional technology Various fixing methods using heat have been proposed in the past, but in recent years, from the viewpoint of downsizing the fixing device and saving power, fixing methods have been proposed in which fixing devices are heated and passed between a pair of rotating rollers that are in pressure contact with each other. , a heating roller type fixing device that fixes a toner powder image on a recording medium such as copy paper is mainly used. In addition, the methods for handling paper jams in electrophotographic devices are mainly to partially open and close the paper path and handle it from the side, or to divide the paper into units, and then take the unit that generated the paper jam out of the device and dispose of it. There is a method in which the main body of the apparatus is configured so that it can be opened and closed so as to be roughly divided into two parts along the paper path, and paper is processed in the open state. In particular, in the case of popular machines, efforts are being made to make them smaller and lighter in order to reduce costs by sharing structures, etc., and the latter configuration is easy to adopt, with an open/close type paper jam removal configuration. An increasing number of electrophotographic devices are employing processing.

Hereinafter, with reference to the drawings, an example of an electrophotographic apparatus in which the above-described heating roller type fixing device is mounted and an open/close type paper jam removal method is adopted will be described.

FIG. 3 is a sectional view of essential parts of an example of a conventional electrophotographic apparatus. In the figure, 1 is a light source, 2 is a document mounting table, 3 is a lens as an imaging means, 4 is a photosensitive drum, and 5 is a uniform charging device that uniformly charges the photosensitive drum 4 by corona discharge. A corotron, 6 is a toner reservoir for development, 7 is a developing sleeve that conveys the toner 16 to the surface of the photoreceptor drum 4, 8 is a recording paper, and 9a and 9b are paper feed rollers that convey the recording paper 8 to the surface of the photoreceptor drum 4. , 10 is a transfer corotron for transferring the toner 15 developed on the photosensitive drum 4 onto the recording paper 8; 11a and 11b are a pair of heat rollers for fixing the toner 15 to the recording paper; 12 is a corotron for static elimination; 13 is a blade that scrapes off the transfer residual toner 16 on the photoreceptor drum 4.

The operation of the conventional electrophotographic apparatus configured as described above will be described next.

When the document 14 placed on the transparent document platform 2 with its copy surface in close contact with it moves over the lens 3 as the document platform 2 moves to the right, it is illuminated by the light source 1. Manuscript 1
4 are sequentially imaged on the surface of the photoreceptor drum 4. At this time, the photosensitive drum 4 rotates in the direction of the arrow, and after the surface is uniformly charged by the corotron 6, the surface of the photosensitive drum 40 is exposed to light at the image formation position. The surface potential of the photosensitive drum 4 charged in a negative manner decreases in accordance with the amount of light received during exposure, and an electrostatic latent image corresponding to the image on the copy surface of the original is recorded. A developing section including a toner reservoir 6 and a developing sleeve 7 conveys the toner 16 charged by stirring to the surface of the photoreceptor drum 40 and attaches it to the electrostatic latent image on the photoreceptor drum 4 by electrostatic force, thereby developing the toner 16. do. On the other hand, the recording paper 8 is moved to a position where the surface of the photoreceptor drum 4, which has completed development, faces the transfer corotron 1o.
sbk, and sent between the photosensitive drum 4 and the transfer corotron 10. At this time, transfer corotron 1
0 performs corona discharge to charge the recording medium 8, and the toner 15 developed on the surface of the photoreceptor drum 4 is attracted to the recording medium 8 by electrostatic force and transferred. Heat roller pair 11a/1
1b are heated to a predetermined temperature and rotate together in pressure contact with each other, so that the recording paper 8 to which the toner 16 has been transferred is
When passing through the pressure contact portion of the heat roller pair 11a, 111), the resin component of the toner 16 is melted and softened by the action of heat and pressure, and is fixed on the recording medium 8. There is residual toner 16 on the surface of the photoreceptor drum 40 after the transfer, but after the charge is removed from the surface of the photoreceptor drum 40 by the static eliminating corotron 12, it is scraped off from the surface of the photoreceptor drum 4 by the blade 13. It is removed and returns to the state where it waits for uniform charging again.

The main body of the electrophotographic apparatus that performs such operations is shown by broken lines, and this main body is configured to be separable into two blocks. Figure 4 shows the main body of the conventional example in Figure 3 opened into two blocks A and B.
, toner reservoir 6.

-, 1 charged corotron 5. The block B includes a blade 13 and the like, and the block B includes paper feed rollers 9a and 9b.

It is configured to include a pair of heat rollers 11a*11b, a transfer corotron 1°, and the like. With such a configuration, when the two blocks A and B are opened, the path for the recording paper 8 is exposed, making it possible to handle paper jams and the like. However, in this case, the pair of heat rollers 11a and 11b are incorporated into the block B without being separated. This is because at least one of the heat roller pairs 11a and 11b is maintained at a high temperature of about 150°C to 200°C, and the other roller also rotates in cooperation with IE50°C to 200°C.
Although the temperature is not 00°C, the temperature is quite high, so if the heat roller pairs 11a and 11b are assembled into two blocks A and B and separated, the heat rollers 11a and 11
This is because the surface of b is exposed and there is a risk of burns during operation. Therefore, the heat roller pair 11a and 11b
When the electrophotographic device is in operation, the heat rollers press against each other, and if the device body is opened due to a paper jam, etc.
It becomes necessary to release the press-contact state of ja and 11b and open the press-contact part.

Next, the structure of the fixing device including the pair of heat rollers 11a and 11b will be described in more detail. FIG. 5 shows an example of a fixing device incorporated in the conventional example shown in FIG. 11a is a heat roller formed by covering the outer circumferential surface of a metal hollow core 34 with a heat-resistant release layer 35; 26 is a heat roller located inside the heat roller 11a and heats the heat roller 11a from the inside; 11b is a heat roller; A pressure roller 26 has a metal core 27 coated with a heat-resistant elastic layer 28 such as silicone rubber, and is rotatably supported at a first fulcrum 3o, and is connected to the pressure roller 11.
31 is the pressure roller 11 supported by the pressure roller support means 26;
a pressure spring that applies a force to press b against the heating roller f1a;
21 is fixed to the main body of the device (not shown) and is a pressure roller 11b.
A pressure roller frame 20 is rotatably supported by a second fulcrum 32 and rotatably supports the heating roller 11a, and a heating roller frame 33 is fixed to the heating roller frame 2o. The latch bin 22 is configured to engage with the latch bin X1 at a predetermined position using a lever rotatably supported at a third fulcrum. Reference numeral 24 denotes a spring that applies force in the fitting direction to the lever 22 so that the fitting does not come off. Since the third fulcrum 23 supporting the lever 22 is fixed to the main body, as shown in this figure, when the lever 22 is engaged with the latch bin 33, the heating roller is moved against the pressure roller frame 21. The position of frame 20 is determined. In this state, the heating roller 11a and the pressure roller 11b come into contact with each other and are pressed against each other by the force of the pressure spring 31. Now, the paper jam is caused by heat roller pair 11a/1.
If the occurrence occurs at the pressure contact part 1b, the heat roller pair 11a, 11
It is necessary to release the pressure contact b and separate the heat roller pair 11a and 1fb from each other. To do this, the lever 22 is rotated in a direction against the force of the spring 24 to release the engagement with the lunch bin 33. With this operation, the heating roller frame 2o is moved around the second fulcrum 32 to the pressure roller 211b.
This allows for rotation in the direction away from the paper, making it easier to clear paper jams.

FIG. 6 shows the heat roller pair 11 & 11b in a separated state. After the paper jam has been cleared, when the heating roller frame 2o is rotated in the direction of pressing against the pressure row 211b, the lever 22 is fitted into the latch bin 33 again, returning to the state in which fixing is possible, that is, the state shown in FIG. 6.

Problems to be Solved by the Invention In such a conventional electrophotographic apparatus, since the main body of the apparatus is largely divided into two along the path of the recording medium, it is easy to handle paper jams when they occur. However, the hot hole of the fixing device~
The fuser is equipped with a latch mechanism such as a lever or latch bin on the fixing device itself to press the heat roller pair, so if a paper jam occurs at the pressure contact part of the heat roller pair, it will be removed after the main body is opened. There is a problem in that it is necessary to further release the latch mechanism, which makes the operation complicated.

Means for Solving the Problems The present invention solves the above-mentioned problems of the conventional art. (5) a heat roller pair consisting of a first roller and a second roller that are rotatable in pressure contact with each other; support means for supporting the first roller so as to be movable along a predetermined path; and pressing the support means. and pressing means for pressing the heat roller pair against each other at the predetermined position, and in conjunction with the closing operation of the main body, the main body presses the support means to the predetermined position. This is how it was done.

Effects The present invention has the above configuration, whereas conventionally a latch mechanism composed of a lever or a latte bin was used to position the support means with respect to the main body and bring the pair of heat rollers into pressure contact with each other. On the other hand, by configuring the support means to be positioned by being pressed by the main body when the main body is closed from the open state, the pressing force that positions the support means at the same time when the main body is open is also released. The conventional operation of the latch mechanism can be eliminated when dealing with paper jams at the press-contact portion of the pair of heat rollers of the apparatus.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

1 and 2 are sectional views of essential parts of an electrophotographic apparatus according to an embodiment of the present invention. The opening and closing structure of the main body is the same as that shown in FIGS. 3 and 4, and the explanation will be centered on the fixing device here. Further, in FIGS. 1 and 2, the same numbers as in FIG. 5 are used to refer to components having the same functions, and the explanation thereof will be omitted.

FIG. 1 shows a state in which the main body is closed and the pair of heat rollers 11a and 11b are in pressure contact and the fixing operation is possible. The heating roller 11a corresponds to a first roller, and the pressure roller 11b corresponds to a second roller. Reference numeral 42 denotes a suppressing protrusion for pressing the heating roller frame 2°, which corresponds to the support means, toward the pressure roller 11b, and is constituted by a part of the main body frame 4o.

The heating roller 7 frame 20, which receives a force in the direction of the pressure roller 11b by the pressure projection 42, is pressed in the direction of the pressure roller 11b and is positioned with the main body closed. At this time, the pressure row 211b is moved by the heating row 2 which is linked to the movement of the support means.
11a is pushed downward, and the pressure spring 31
As a result, the two pairs of rows 11a and 11b are brought into pressure contact with each other.

FIG. 2 shows the embodiment of FIG. 1 in an open state. As the suppressing protrusion 42 moves upward with the movement of the main body, the pressing force is removed.
The heating roller frame 2o can move in the direction of separating the heating roller pairs 11a and 11b from each other.
Paper jams in the pressure contact portions a and 11b can be easily disposed of.

Effects of the Invention As described above, the present invention includes a main body configured to be openable and closable almost with the passage of a recording medium as a boundary, and a first roller and a second roller that are incorporated into the main body and are rotatable while being in pressure contact with each other.
a pair of heat rollers consisting of rollers; a support means for movably supporting the first roller along a predetermined path; and a pair of heat rollers that is moved to a predetermined position by pressing the support means; and a pressing means for pressing the fixing device against each other, and the main body presses the supporting means to the predetermined position in conjunction with the closing operation of the main body, thereby simplifying the structure by eliminating the pressing latch mechanism of the fixing device. This has the excellent effect of improving the operability of handling paper jams.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an electrophotographic apparatus according to a first embodiment of the present invention, FIG. 2 is another state diagram of the embodiment of FIG. 1, and FIG. 3 is a sectional view of a conventional electrophotographic apparatus. , FIG. 4 is another state diagram of the conventional example shown in FIG. 3, FIG. 5 is a sectional view of essential parts of the electrophotographic apparatus in the conventional example shown in FIG. 3, and FIG. 6 is another state diagram of the conventional example shown in FIG. be. 1...Light source, 2...Document mounting table, 3.
... Lens, 4... Photoreceptor drum, 7.
... Sleeve, 1o ... Transfer corotron, 11a ... Heating roller, 11b ...
・Pressure roller, 20...Heating roller frame,
21... Pressure roller frame, 40...
・Main body, 42...Press projection. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
11 Yuangen 2-11 Hara Kisai l mo 3---uns 4---; 喹Buhizeto Drum//ku---Power I11 Takakai Roller//b---Ichiwa San Roller (//l ), //b) - Ichijuku Laura vs.
Part 4
Ward//ku---Heating roller//b---Ika 21E roller 22---Refku- 33---La soshibin/lθ Fig. 6

Claims (1)

[Claims] a main body configured to be openable and closable substantially with the path of the recording medium as a boundary; a heat roller pair consisting of a first roller and a second roller incorporated in the main body and rotatable in a state in which they are in pressure contact with each other; The main body has a support means for movably supporting the roller along a predetermined path, and a pressing means for moving the roller to a predetermined position by pressing the support means and pressing the pair of heat rollers against each other at the predetermined position. An electrophotographic apparatus characterized in that the main body presses the support means to the predetermined position in conjunction with a closing operation of the electrophotographic apparatus.