JPH04305662A - Image forming device - Google Patents

Abstract

PURPOSE:To perform jamming processing without contaminating a roller by toner even in the case that paper jamming occurs between the rollers for fixing in an image forming device. CONSTITUTION:This device is provided with a rocking plate 15 which engages with either the fixing roller 11 or the pressure roller 12 of a fixing device 10 and allows the roller 11 or 12 to press or separate each other by interlocking with the rocking of a paper ejection part 20 which can open a paper ejecting side between both rollers 11 and 12. Then, a frame member 18 which peels off a transfer paper from the roller 11 or 12 by interlocking with the rocking plate 15 is provided. When jamming occurs between the rollers 11 and 12, the paper ejection part 20 is rocked to open the paper ejection side of the fixing device 10, and the rollers 11 and 12 are separated to perform the jamming processing.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus employing electrophotography, such as a copying machine or a laser beam printer.

0002

2. Description of the Related Art In image forming apparatuses such as copying machines, if the apparatus is operated as it is when an abnormality such as a paper jam occurs, malfunctions such as damage to internal equipment may occur. It is set to be cancelled. Then, the apparatus can be restarted only after the user removes the jammed paper or the like.

On the other hand, an image forming apparatus is equipped with a heat fixing device consisting of a fixing roller that has an internal heat source and rotates in a predetermined direction, and a pressure roller that rotates in pressure contact with the fixing roller. There are also many. This fixing device passes a transfer paper carrying an unfixed toner image between fixing and pressure rollers, heats and presses the toner image, melts and fixes it onto the transfer paper, and fixes it as a permanent image. be.

[0004] If a paper jam occurs between the fixing roller and the pressure roller of the fixing device, if the jammed paper is pulled out while the fixing roller is cold, the unfixed toner on the jammed paper will be transferred to the fixing roller side. It will stick to the fuser roller and stain it.
This causes the inconvenience of staining the transfer paper during the next fixing process.

For this reason, when a paper jam occurs between the fixing roller and the pressure roller, the jammed paper should not be pulled out with normal human force, and the jammed paper should be removed using a special knob for removing the jam. etc. are rotated slowly to gradually remove the jammed paper. In this case, even if the fixing roller is somewhat cold, the jammed paper moves slowly between the fixing roller and the pressure roller, so the unfixed toner image on the jammed paper is fixed on the jammed paper, and the fixing roller moves the jammed paper away from the jammed paper. No toner will stick to it.

[0006]

However, if a paper jam occurs between the fixing roller and the pressure roller, the temperature of the fixing roller will drop sufficiently if the user clears the jam after some time. Even if the jammed paper is slowly fixed using the knob and ejected from between the pressure rollers, there is a problem in that the toner on the jammed paper is not fixed and adheres to the fixing roller.

The present invention has been made in view of the above problems, and its object is to form an image in which even if a paper jam occurs between the fixing rollers, the jam can be cleared without staining the rollers with toner. We are in the process of providing equipment.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a pair of rollers for thermal fixing that rotate in pressure contact with each other, and a transfer paper that has been fixed and that has passed between the rollers and is carried out to the outside. In an image forming apparatus, the paper ejecting section is engaged with one of the pair of rollers, and the ejecting section is configured to open the pressure contact portion of the pair of rollers to the outside by swinging in one direction. a swinging member that allows the pair of rollers to be pressed or separated from each other in conjunction with the swinging member; and a peeling member that peels off the transfer paper from one of the pair of rollers in conjunction with the swinging of the swinging member. It is characterized by

[0009]

[Operation] When a jam occurs in the transfer paper between the pair of fixing rollers, the paper discharge section is swung to one side to expose the pressure contact portion of the pair of rollers to the outside. In this case, the swinging member moves in conjunction with the swinging of the paper discharge section to separate the pair of rollers from each other. In addition, in this case, the transfer paper is rolled by the peeling member.
It is torn off from one side of the pair. If the jammed paper between the roller pair is removed in this state, the jam can be easily cleared without causing the toner on the jammed paper to adhere to the roller pair.

[0010] Furthermore, when the paper jam removal is completed, if the paper ejecting section is swung back to its original position, the swiveling member also moves in conjunction with this, and the pair of rollers are brought into pressure contact with each other and ready for fixing. Become.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described with reference to the accompanying drawings.

First, a first embodiment of the present invention will be explained with reference to FIGS. 1 to 3.
This is explained by:

FIG. 1 shows a side view of a fixing device 10, a paper discharge section 20, etc. of an image forming apparatus.
A pressure roller 12 made of an elastic body that rotates in pressure contact with the fixing roller 11, and a casing 13 (
(see Figure 2). As shown in FIG. 2, the fixing roller 11 has both ends connected to the casing side plates 13.
a, 13a, and is rotated by a rotary drive means (not shown), and the pressure roller 12 has shaft portions 12a, 12a at both ends that swing left and right through bearings 14, 14. It is pivotally supported by plates 15,15.

As shown in FIG. 1, the swing plate 15 is long in the front and back, and its front end is supported by a support shaft 16 protruding from the casing side plate 13a. One end of the front end of the swing plate 15 is connected to the other end of a spring member 17 fixed to the casing side plate 13a, and the spring member 17 urges the swing plate 15 clockwise around the support shaft 16 in FIG. ing. Therefore, the pressure roller 12
, 17 in the clockwise direction, pressure is applied to the fixing roller 11, and a nip N for fixing is formed between the fixing roller 11 and the fixing roller 11. It is assumed that the pressure roller 12 is rotationally driven via the fixing roller 11 and the like.

The paper discharge section 20 is for discharging the transfer paper P discharged from the fixing device 10 to the outside of the main body of the image forming apparatus, and as shown in FIG. It is placed on the side. The paper ejection section 20 includes a frame 21, a paper ejection roller (not shown) pivotally supported between the frame 21, and a paper ejection roller (not shown) whose tip end is disposed close to the fixing roller 11 and the pressure roller 12. , lower separating claws 22, 23, etc.

The left and right side plates 21a (only one side is shown in FIG. 1) of the frame 21 are trapezoidal in shape, and their lower portions are pivoted to the main body of the apparatus via a support shaft 24. is positioned above the rocking plate 15 whose lower end extends forward, and has the function of controlling the rotation of the rocking plate 15 by the spring 17. In addition, the left and right rocking plates 15,1
As shown in Figure 1, between 5 and 5 is made of wire etc.
A U-shaped frame member 18 is attached, and its upper part is disposed above the upper separating claw 22, as shown in FIG.

That is, when the toner image T is transferred onto the transfer paper P via a photosensitive drum, a developing device, etc. (not shown), the transfer paper P is placed with the toner image T facing the fixing roller 11 side. It is carried into the fixing device 10. As shown in FIG. 1, when the transfer paper P is conveyed while being held between the fixing roller 11 and the pressure roller 12, the toner image T on the transfer paper P is transferred between the fixing roller 11 and the pressure roller 12. The image is heated and pressurized by the nip portion N of the image forming apparatus to be melted and fixed, and is fixed on the transfer paper P as a permanent image.

The transfer paper P on which the fixing work has been completed is delivered to the paper ejection section 20.
The sheet is separated from the fixing roller 11 or the pressure roller 12 by the upper or lower separating claw 22 or 23, and is discharged to the outside of the apparatus main body via the paper discharge roller of the paper discharge section 20.

Now, if a paper jam (jam of transfer paper P) occurs in the main body of the apparatus, the apparatus stops the image forming operation,
Power supply to the heat source of the fixing roller 11 of the fixing device 10 is also stopped. Then, the user is required to clear the jam. Here, if a jam occurs between the fixing roller 11 and the pressure roller 12, if the jam is cleared after some time, the temperature of the fixing roller 11 will have cooled down sufficiently.
The toner on the jammed paper P' adheres to the fixing roller 11 side,
This toner also adheres to the pressure roller 12, causing the inconvenience that this toner adheres to other transfer sheets P during the subsequent fixing operation.

Hereinafter, a method for handling a paper jam when a paper jam occurs between the fixing roller 11 and the pressure roller 12 will be explained with reference to FIGS. 1 and 3.

If a jam of the transfer paper P occurs in the fixing device 10, the upper part of the paper discharge section 20 is moved to the support shaft 24 as shown in FIG.
When the fixing device 10 is tilted backwards, the rear side of the fixing device 10 is opened to the outside, and the jammed paper P' can be taken out from here. In this case, the lower rear end A of the side plate 13a of the paper discharge section 20 is
As the paper discharge section 20 rotates, the swing plate 15 is rotated counterclockwise around the support shaft 16, so the pressure roller 12 also moves downward together with the swing plate 15, and the pressure roller 12 is separated from the fixing roller 11 with a certain gap. Then, the jammed paper P' is moved toward the pressure roller 12 by the frame member 18 (the state shown in FIG. 3).

In this state, the jammed paper P' is removed from the paper discharge section 20 side.
If the jammed paper P' is removed from the main body of the apparatus, the toner on the jammed paper P' will not adhere to the fixing roller 11, and the jammed paper P' will be removed.
' can be easily removed. When the jam removal is completed, the paper discharge section 20 is rotated to the original position via the support shaft 24, and the swing plate 15 moves the pressure roller 12 to the fixing roller 11 by the action of the spring member 17. It returns to the original position where it was pressed, and the fixing work can be performed again using the fixing and pressure rollers 11, 12, etc.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.
This is explained by: Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, the side plate 21a of the sheet discharge section 20 and the swing plate 15 are connected by a spring member 25, and the rotation of the sheet discharge section 20 causes the swing plate 15 to swing around the support shaft 16. Therefore, the pressure roller 12 is configured to press the fixing roller 11 or to separate it from the fixing roller 11.

That is, the rear side B of the side plate 21a of the paper discharge section 20
point and the rear end point C of the swing plate 15 are connected by a spring member 25, and the swing plate 15 is biased clockwise in FIG. 4 about the support shaft 16 to fix the pressure roller 12. It is brought into pressure contact with the roller 11. Here, in the first embodiment, the swing plate 15
The lower part A of the front end of the side plate 21a of the paper ejecting unit 20 that has been pushed down is cut, and the inlet side of the fixing device 10 is also cut.
A front frame member 19 made of a wire shaped like a square is a swing plate 15.
is fixed.

If a jam occurs in the fixing device 10, as shown in FIG. Paper ejection section 2
The support point B of the spring member 25 of the side plate 21a of No. 0 descends and approaches the support point C of the paper discharge section 20, so the elastic force of the spring member 25 disappears, and the rear side of the swing plate 15 moves toward the paper discharge section 20. is pushed down by the side plate 21a. Therefore, the swing plate 15 rotates counterclockwise around the support shaft 16 as shown in FIG.
The pressure roller 12 is lowered and separated from the fixing roller 11. In this case, the jammed paper P' is moved toward the pressure roller 12 by the frame member 18 and the front frame member 19.

If the jammed paper P' is removed in the above state, the jam can be easily cleared without causing the toner on the jammed paper P' to adhere to the fixing roller 11. When the jam removal is completed, the paper discharge section 20 is rotated to its original position, the swing plate 15 is also returned to its original position by the action of the spring member 25, and the pressure roller 12 is pressed against the fixing roller 11. Then, the fixing work becomes possible.

[0028]

As is clear from the above description, according to the present invention, the fixing roller pair is interlocked with the movement of the paper ejecting section, which allows the pressing portion of the fixing roller pair to be opened to the outside by its swinging. Since the rollers are pressed or separated, even if a jam of the transfer paper occurs between the pair of rollers, the jam can be easily cleared without causing toner to adhere to the pair of rollers.

[Brief explanation of drawings]

FIG. 1 is a side view of the vicinity of a fixing device and a paper discharge section of an image forming apparatus according to a first embodiment.

FIG. 2 is a view taken along the line XX in FIG. 1;

FIG. 3 is an explanatory diagram of the operation of a fixing device and a paper discharge section of the image forming apparatus according to the first embodiment.

FIG. 4 is a side view of the vicinity of a fixing device and a paper discharge section of an image forming apparatus according to a second embodiment.

FIG. 5 is an explanatory diagram of the operation of a fixing device and a paper discharge section of the image forming apparatus.

[Explanation of symbols]

11 Fixing roller (roller) 12 Pressure roller (roller) 15 Rocking plate (swinging member) 18 Frame member (tear-off member) 20 Paper ejection section

Claims (1)

[Claims] 1. A pair of thermal fixing rollers that rotate in pressure contact with each other, and a fixed transfer paper that has passed between the pair of rollers is carried out to the outside, and by swinging in one direction, the pair of rollers is rotated. In an image forming apparatus having a paper ejecting part whose pressure contact part can be opened to the outside, an image forming apparatus that engages with one of a pair of rollers and can press or separate the pair of rollers from each other in conjunction with the swinging of the paper ejecting part. An image forming apparatus comprising: a swinging member that moves the swinging member; and a peeling member that peels off the transfer paper from one of a pair of rollers in conjunction with the swinging of the swinging member.