JPH10301432A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device having a fixing unit whose handleability is excellent by providing it with the fixing unit freely attached to and detached from a slide rail and an operation means allowing the drawing-out of the fixing unit and releasing the press-contact of a pair of fixing rollers arranged in the fixing unit. SOLUTION: The fixing unit 10 is constituted so that it can be drawn out forward while being held by the slide rail 13. An engagement mechanism 19 arranged in the unit 10 is detached from a main body frame 15 by rotating a rotary lever 14 for drawing out the unit 10 when the unit 10 is drawn out, and the unit 10 can be drawn out. In such a case, a pressure roller 12 is separated from a heating roller 11 when an oscillation cam 18 formed on the coaxial shaft 30 of the rotation center of the lever 14 is rotated synchronously with the rotating action of the lever 14, and the fixing rollers do not mutually receive pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus, and more particularly to an electrophotographic apparatus having a fixing unit which can be pulled out of an electrophotographic apparatus main body.

[0002]

2. Description of the Related Art A conventional pressure-heating type fixing unit in an electrophotographic apparatus is provided with a pressure applying mechanism for pressing a pressure roller against a heating roller inside a frame constituting the fixing unit. Is common. That is, the fixing unit usually rotates a heating roller made of metal and a pressure roller having an elastic layer such as silicon rubber by pressing against the heating roller, and simultaneously applying heat energy and pressure energy to the printing paper or the like. The toner is fixed on the recording medium. Here, in the conventional fixing unit, a pressing mechanism (spring mechanism portion) is often mounted inside the fixing unit in order to apply the pressing force of the fixing roller evenly. In this case, since the pressing mechanism can be mounted in the same frame as the fixing frame reference surface on which the heating roller bearing and the like are fixed, it is relatively easy to apply the pressing force evenly, but the proper fixing is performed. Adjustment was sometimes required to obtain the roller pressing force (nip width). In this case, it is necessary to replace the spring applying the pressing force or to change the set length of the spring, which has caused a considerable increase in manufacturing cost.

[0003] Further, in a device without a pressure release mechanism, since the heating roller and the pressure roller are constantly pressed, the elastic portion of the pressure roller is permanently deformed (deteriorated) if the pressure contact state is continued for a long period of time. As a result, there was a problem that the fixing unit could not be used. Therefore, in order to prevent such a problem in the past, in the printing state of the device, the pressing and releasing of the fixing roller is automatically performed, or when the period during which printing is not performed such as during transportation of the printing device or long-term storage is expected to be long beforehand, In order to prevent the above problem, a member such as a spacer is inserted between the fixing rollers.

[0004] However, in the case where printing is possible and the pressing and releasing of the fixing roller are automatically performed,
There is a drawback that the device mechanism becomes complicated and the device cost becomes extremely high. Further, in the case where the spacer is provided only at the time of transportation, if a paper jam or the like occurs during the use of the printing apparatus, there is a disadvantage that the pressing and contacting cannot be canceled and the operation is difficult. Therefore, before the life of the normal fixing unit is reached, the fixing unit often needs to be replaced due to deformation of the pressure roller, damage to the fixing roller due to a jam removing operation, or the like.

[0005] As for the draw-out mechanism of the fixing unit, conventionally, the fixing unit is fixed to the main body frame by screws or fixed by an engagement mechanism. in this case,
When a paper jam or the like occurs, the fixing unit cannot be easily attached and detached, so that the operability is poor. In recent years, there has been proposed a type in which the fixing unit is placed on a sheet metal guide or the like, and is pulled out.However, it is difficult to work due to the resistance of the sheet metal guide at the time of pulling out. There is a drawback that the fixing unit cannot be easily attached or detached, or that the fixing unit cannot be easily attached or detached upward without removing a member such as a screw that fixes the guide and the fixing unit. Since the fixing unit is usually at a high temperature, it is difficult for an operator to perform the above operation, which has been a major problem in recent years.

[0006]

In the above prior art, when a failure such as a jam occurs, a mechanism for easily attaching and detaching the fixing unit and a mechanism for releasing the pressure contact of the fixing roller are not provided. There was a disadvantage that it was bad.
Similarly, since there is no mechanism for easily adjusting the pressure contact force (nip width) of the fixing roller and a mechanism for preventing deformation of the fixing roller caused during transportation of the fixing unit, productivity and reliability are deteriorated. Was.

An object of the present invention is to provide an electrophotographic apparatus provided with a fixing unit which can solve the above-mentioned drawbacks and is easy to handle.

[0008]

An object of the present invention is to provide a slide rail supported so as to be able to be pulled out of an electrophotographic apparatus main body,
A fixing unit detachably held on the slide rail; a fixing unit configured between the electrophotographic apparatus main body and the fixing unit; and a drawer permitting withdrawal of the fixing unit to the electrophotographic apparatus main body, and a fixing roller provided in the fixing unit. This is achieved by having operating means for canceling the pressure contact between the pair.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a paper feed roller, 2 is a registration roller, 3 is a photoreceptor, 4 is a transfer device, 5 is a developing device, 6 is a laser beam, 7 is a charger, 8 is a cleaner, 9 is recording paper, 10 Is a fixing unit, 13 is a slide rail, 1
5 is a main body frame, 21 is a paper discharge roller, 22 is a stacker, 24 is a transport roller, and 25 is a toner image.

The electrostatic latent image formed on the surface of the photoconductor 3 by the laser beam 6 is developed by the developing device 5 as a toner image 25. On the other hand, the recording paper 9 sent out one by one by the paper feed roller 1 reaches the registration roller 2 via the conveyance roller 24, and corrects the posture of the recording paper 9 in the paper conveyance direction by the registration roller 2 to transfer the recording paper 9 to the transfer device 4. Sent to. The toner image 25 on the photoconductor 3 is transferred onto the recording paper 9 by the transfer device 4,
The recording paper 9 holding the toner image 25 is sent to the fixing unit 10. In the fixing unit 10, the toner image 25
Is fixed on the recording paper 9 by applying heat and pressure,
The paper is discharged to the stacker 22 by the paper discharge roller 21.

Next, a drawing configuration of the fixing unit 10 in this embodiment will be described with reference to FIG. While the fixing unit 10 is held on the slide rail 13,
It can be pulled out to the front. In this configuration, the fixing unit 10 of about 5 kgf is mounted on the slide rail 1.
Although it was engaged with No. 3, the pull-out force was only about 1/4 compared with the conventional sheet metal configuration, and the operability was remarkably improved. Further, the fixing unit 10 is configured to be dropped from above the slide rail 13, and is configured to be easily detachable upward by a fixing unit attaching / detaching handle 23 provided on the fixing unit 10. This configuration also has much improved operability as compared with the prior art.

Further, the rotation lever 14 for pulling out the fixing unit 10 is rotated when the fixing unit 10 is pulled out, so that the engaging mechanism 19 provided on the fixing unit 10 is disengaged from the main body frame 15 to fix the image. The unit 10 is configured to be able to be pulled out. This configuration also requires only one operation because the rotary lever 14 also serves as a handle for pulling out the fixing unit 10 at the same time, so that the operability is significantly improved as compared with the conventional systems. In this case, in synchronization with the rotation of the rotary lever 14, the swing cam 18 provided on the coaxial shaft 30 at the center of rotation of the rotary lever 14 rotates, and the press-contact link 17 rotates about the position of the fulcrum. The pressure roller 12 is separated from the heating roller 11 by extending the pressure contact spring 16, so that the fixing rollers are in a state where they do not receive pressure from each other. If the fixing roller attempts to insert into the main body in a state where the pressure is released, the engagement mechanism 19 interferes with the main body frame 15 and does not enter the predetermined insertion position, so that the front cover 20 cannot be closed and the printable state is set. No. Thereby, the fixing unit 10
It is possible to prevent a serious trouble due to poor contact of the power supply device due to forgetting to press the fixing roller.

Further, since the fixing unit 10 is a device that requires periodic replacement, it is packed and transported in a unit of replacement of the fixing unit 10 alone. In this case, no pressure is applied between the fixing rollers as described above. Since the rotation lever 14 can be fixedly fed to the position, the pressure roller 12 can be used for a long time without any trouble such as permanent deformation of the pressure roller 12. As described above, in the present embodiment, it has become possible to provide a highly reliable electrophotographic apparatus which has much better operability than the conventional fixing unit configuration and also has sufficient safety.

Next, the mechanism for adjusting the pressing force of the fixing unit 10 in this embodiment will be described with reference to FIG. In the fixing unit 10, the pressure roller 12 is attached to the heating roller 11 fixed to the fixing frame 26, and the press-contact link 17 configured to be rotatable about a fulcrum 27 on the fixing frame is attached to the fixing frame 26. The mechanism is configured to be pressed by a pressing spring 16 with a predetermined pressing force. In the adjusting mechanism of this embodiment, the fulcrum 27 of the press-contact link 17 is fixed to the eccentric fixing hinge 28 with the screw 29. Pressing link 17 on fixing frame 26
When fixing is performed, the pressure contact force can be adjusted by rotating the fixing hinge 28. As compared with the conventional fixing unit, it is possible to apply a predetermined pressure contact force only by rotating the fixing hinge 28, so that print quality failures such as paper wrinkles and fixing defects due to imbalance of the nip width are prevented. It became possible to overcome it easily.

[0015]

As described above, according to the present invention, it is possible to provide an electrophotographic apparatus provided with a fixing unit having good handleability.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus of the present invention.

FIG. 2 is a perspective view of a main part of a fixing unit according to the present invention.

FIG. 3 is a schematic view of a pressing force adjusting mechanism of the fixing unit according to the present invention.

[Explanation of symbols]

10: fixing unit, 11: heating roller, 12: pressure roller, 13: slide rail, 14: rotating lever, 15
... body frame, 16 ... pressure contact spring, 17 ... pressure contact link, 18 ... swing cam, 19 ... engagement mechanism, 26 ... fixing frame, 27 ... fulcrum, 28 ... fixing hinge, 29 ...
Screw, 30 ... shaft.

Claims (1)

[Claims] An electrophotographic apparatus comprising: a slide rail detachably supported by a main body of the electrophotographic apparatus; a fixing unit detachably held on the slide rail; and a fixing unit between the main body of the electrophotographic apparatus and the fixing unit. An electrophotographic apparatus, comprising: an operation unit for permitting withdrawal of a fixing unit with respect to a photographic apparatus main body and releasing pressure contact of a fixing roller pair provided in the fixing unit.