JP3129496B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method (a method in which an image formed on a photoreceptor is transferred to a sheet such as a sheet of paper or an envelope for recording), such as a laser printer, a laser copying machine or a laser facsimile. And an electrophotographic apparatus for performing recording. More specifically, the present invention relates to an electrophotographic apparatus in which a sheet after image transfer is placed in a fixing device, where heat and pressure are applied to fix a transferred image on the sheet.

[0002]

2. Description of the Related Art Conventionally, for example, in a fixing device 1 of a laser printer, as shown in FIG.
The roller 3 and the pressure roller 4 are housed by being pressed against the roller 3. The heating roller 3 is covered with a heat insulating material 5, and the heat insulating material 5 is further covered with a fixing device cover 6. When the jammed paper is processed, the heating roller 3 is inadvertently handed. Safety was ensured without touching.

[0003]

However, in the conventional laser printer, since the fixing device cover 6 covering the heat insulating material 5 is fixed and provided, it is difficult to remove the sheet at the position of the fixing device 1 and it is troublesome. was there. SUMMARY OF THE INVENTION It is an object of the present invention to facilitate jam clearance of a sheet at a fixing device position.

[0004]

For this purpose, the present invention has the following features.
Fuser 25 for example Ka圧Ro - fixing rotary member such as La 37 covered with a heat insulating material 39, in the electrophotographic apparatus covering in addition fuser cover 44 the heat insulating material 39, the fixing unit
The cover 44 is composed of the front cover 44 and the rear cover 4.
It provided separately on the 4, characterized by comprising as can jam processing position <br/> or in open Kukoto each sheet S.

According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, a sheet transport guide portion 44b is provided integrally with the fixing device cover 44, as shown in the following embodiments. It is characterized by the following.

According to a third aspect of the present invention, there is provided an electrophotographic apparatus according to the first aspect, wherein the fixing device cover 44 is closed between the fixing member cover 44 and the heat insulating material 39, as shown in the following illustrated embodiments. The air gap 47 is formed.

According to a fourth aspect of the present invention, in the electrophotographic apparatus according to the first aspect, for example, as shown in the following embodiment, the fixing rotating member 37 is formed by a roller, and the fixing device cover 44 is formed. Roller shaft 3 of the roller when closed
The fixing device cover 44 is positioned by abutting the fixing device cover 7a.

According to a fifth aspect of the present invention, in the electrophotographic apparatus according to the first aspect, the opening and closing of the fixing device cover 44 is linked to the opening and closing of the apparatus main body cover 10a, as shown in the following embodiments. It is characterized by becoming.

According to a sixth aspect of the present invention, in the electrophotographic apparatus according to the fifth aspect, as shown in the following embodiments, the fixing device cover 44 is attached to the fixing device cover 44 via a heat insulating elastic member 50. It is characterized in that the cover 51 is brought into contact with the cover 10a to partition the space 51 therebetween.

[0010]

According to the first aspect, the fixing device 2 is provided.
When the sheet is jammed in step 5, the fixing device cover 44 is opened to the jam processing position and then the jammed paper is removed.

According to the second aspect of the present invention, the sheet S after the image transfer is guided by the sheet transport guide portion 44b and guided to the fixing device 25.

According to the third aspect, heat is blocked by the air gap 47.

According to the fourth aspect, when the apparatus body cover 10a is closed, the fixing unit cover 44 is positioned by abutting against the roller shaft 37a.

The fixing device cover 44 is opened and closed in conjunction with the opening and closing of the apparatus body cover 10a.

According to the sixth aspect, when the apparatus body cover 10a is closed, a space 51 between the apparatus body cover 10a and the fixing device cover 44 is partitioned by the heat insulating elastic member 50.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 shows an overall schematic configuration of an internal mechanism of a laser printer according to an embodiment of the present invention.

The reference numeral 10 in the drawing denotes an apparatus main body. The apparatus main body 10 is freely provided off the apparatus main body cover 10 a of the device main body case 10b around the hinge 10c. In the apparatus main body 10, a belt-shaped photoconductor 11 is provided substantially at the center. Around the photoconductor 11, a charger 12, a developing device 13, a transfer device 14, and a cleaning device 15 are arranged in this order in the driving direction indicated by the arrow in the drawing. Then, the optical writer 16 is arranged below the charger 12 and the cleaning device 15. Also, below the optical writer 16,
The sheet cassette 18 in which the sheets S are set is detachably attached. Further, on the right front side of the apparatus main body 10 in the drawing, a manual paper feed tray 19 is provided near the upper part thereof. On the upper side of the apparatus main body 10, a first discharge stack unit 20 is provided. On the rear side on the left side in the figure, there is provided a second paper discharge stack unit 21 capable of discharging a stiff sheet such as a thick paper or an envelope or a stiff sheet such as an OHP sheet, a second original drawing, or a paper. Then, a paper discharge tray 22 is detachably attached to the second paper discharge stack 21.

Thus, the sheet feeding roller 23 is driven to feed the sheet S in the sheet feeding cassette 18 in the direction of arrow A. Then, the sheet S is fed to the upper side of the photoconductor 11 by the registration roller 24 with a timing. The photoreceptor 11 is driven in a counterclockwise direction as shown by an arrow.
The surface is uniformly charged by the charger 12 and the optical writer 1
The electrostatic latent image is formed on the photoreceptor 11 by irradiating the laser beam L from 6. This latent image is visualized by the toner when passing through the developing device 13. Then, the visible image is transferred by the transfer device 14 to the lower surface of the sheet S conveyed above the photoconductor 11. After the transfer, the sheet S is conveyed to the fixing device 25, where heat and pressure are applied to fix the transferred image on the sheet S.

After the image is fixed, the sheet S is sent out from the fixing device 25 by a paper discharge roller 28, further guided upward by a conveyance guide 29, inverted, and discharged by a paper discharge roller 30 in the direction of arrow B to be first discharged. The sheets are sequentially stacked on the stack unit 20. When the sheet S is an envelope, an OHP sheet, or the like, the sheet discharge direction is switched by the switching guide 31 and sent out in the direction of the arrow C by the sheet discharge roller 28, and the sheets are sequentially stacked on the second sheet discharge stack unit 21.

On the other hand, the surface of the photoreceptor 11 after the transfer of the visible image is cleaned by a cleaning unit 15.

1 and 2, the fixing device 25 is supported by a fixing frame (not shown) and includes a heating roller 36 serving as a fixing rotating member. The pressure roller 37 is housed. The heating roller 36 has a built-in heater 38. On the other hand, the pressing roller 37 is pressed against the heating roller 36 by an appropriate urging means. A heat insulating material 39 is provided over the pressure roller 37 in the drawing. The heat insulating material 39 is bent downward at two curved portions 39a and 39b on the left and right sides in the middle of the width to form a concave cross section, and covers the semicircle in the axial direction of the pressure roller 37. Provided. In the center of the width of the heat insulating material 39, a plurality of small window holes 39c are opened,
Bearings 39d are provided upright at both front and rear ends in the figure.

The rotating shaft 43 is extended between the bearings 39d.
And supported on the rotating shaft 43 on the heat insulating material 39.
Is provided with a fixing device cover 44 over the cover. Its fixation
The container cover 44 is formed of a conductive resin plate,Sheet S
Before fixing provided at the entrance side of the fixing device 25 along the transport direction
Cover 44 and the fixing-side cover 44 provided on the outlet side.
Division,Each of the rotating shafts 43As the centerPivotableWhen
Do.Pre-fixing cover 44 and post-fixing cover 44
Are provided with curved portions 44a at the base end on the rotating shaft 43 side.
In addition, each base end is rotatably provided on the rotation shaft 43.
Provided with an urging member (not shown) for urging upward in the drawing.
You. The fuser covers 44, 44
Breaks at the tip and the tip hangs down, between the insulation 39
With the air gap 47 provided and covering the heat insulating material 39
And the sheet conveyance guides 44b at the end
Form. The sheet conveyance guide portion 44b on the right in the figure is a sheet
A sheet conveyance guide section on the left in the figure, which is a guide before fixing of S
44b is a guide after fixing the sheet, and
It is located on the transport path 48. The air gap 4
The inside of FIG. 7 communicates with an exhaust unit not shown.

On the outer surface of the fixing device covers 44,
For example, a heat insulating elastic member 50 such as a urethane sponge
Are provided by pressing against each other. The heat insulating elastic member 50
Is an elongated rod shape having a rectangular cross section, and the device body cover 10
a attached to each of the partition portions 10d provided in
A space 51 is defined between the apparatus body cover 10a and the fixing device covers 44. A plurality of ventilation windows 10e are opened in the apparatus body cover 10a above the fixing device covers 44.

When the apparatus main body 10 is driven, the sheet S after the image transfer is stably conveyed without any flutter due to the electrostatic attraction of the sheet conveyance guide portion 44b. When the fixing device 25 is driven, heat is radiated from the heat insulating material 3.
9 escapes to the air gap 47 through the small window hole 39c, and is discharged to the outside of the apparatus main body 10 by the exhaust means. Also,
The fixing device covers 44 are cooled through the ventilation windows 10e of the apparatus body cover 10a. Further, heat transmitted from the fixing device 25 is blocked by the heat insulating elastic member 50.

On the other hand, when a jam occurs at the position of the fixing device 25, the apparatus main body cover 10a is rotated counterclockwise about the hinge 10c and opened, and an urging member not shown in FIG. The fixing device cover 44
44 is opened in a wing shape around the rotation shaft 43. Then, it is opened to the jam clearing position, and the sheet conveying guides 44b are separated while covering the heat insulating material 39 to open the sheet conveying path 48. Thus, the jammed paper can be easily removed from the opened sheet conveying path 48 without touching the fixing device 25. In this jam clearing position, the curved portions 4 of the fixing device covers 44,
4a and 44a prevent the fixing device cover 44 from opening further.

On the other hand, when the apparatus body cover 10a is closed after the jam has been cleared, the heat insulating elastic member 50 is pressed against the fixing device covers 44, 44, and the fixing device covers 44, 44 are pressed.
4 is closed against the urging member, and the state shown in FIG. 1 is obtained.

In the illustrated embodiment described above, when the fixing unit covers 44 are closed, the fixing unit cover 44 is pressed against the urging member by the apparatus body cover 10a without providing a stopper. The position is determined at a predetermined position. However, as shown in FIG. 4, a bent portion 44c is provided on each side of the sheet conveying guide portions 44b, 44b with the roller shaft 37a of the pressure roller 37 interposed therebetween.
44c may be provided so that when the fixing device covers 44 are closed as shown in the drawing, the fixing device covers 44 abut against the roller shaft 37a for positioning.

[0028]

According to the first aspect of the present invention, the fixing device cover is provided with a fixing front cover and a fixing rear cover.
The jammed paper is removed after the sheet is opened to the paper jam clearing position .
It can be done very easily from the side.

According to the second aspect of the present invention, since the sheet is guided by the sheet transport guide section, there is no need to provide a separate sheet transport guide, and the number of parts can be reduced and cost can be reduced.

According to the third aspect of the present invention, since heat is blocked by the air gap, the temperature rise of the fixing device cover can be prevented. Further, by communicating the air gap with the exhaust means, the hot air of the fixing device can be discharged to prevent the temperature inside the apparatus main body from rising.

According to the fourth aspect of the present invention, when the apparatus main body cover is closed, the fixing unit cover is positioned by abutting against the roller shaft, so that, for example, the sheet conveyance by the sheet conveyance guide portion is made smooth. be able to.

According to the fifth aspect, the fixing device cover is opened and closed in conjunction with the opening and closing of the apparatus body cover.
Jam clearing work becomes easy.

According to the sixth aspect of the present invention, heat is blocked between the apparatus body cover and the fixing device cover and by the heat insulating elastic member, so that the apparatus body cover can be prevented from becoming hot.

[Brief description of the drawings]

FIG. 1 shows a laser printer according to an embodiment of the present invention;
FIG. 2 is a schematic configuration diagram near a fixing device when the apparatus main body cover is closed.

FIG. 2 is a perspective view thereof.

FIG. 3 is a state diagram of the fixing device when the apparatus main body cover is opened.

FIG. 4 is a schematic diagram of another example of the fixing device, showing the vicinity of the fixing device when the apparatus body cover is closed.

FIG. 5 is a schematic configuration diagram of the entire internal mechanism of the laser printer.

FIG. 6 is a schematic configuration diagram of a fixing device in a conventional laser printer.

[Explanation of symbols]

 10a Device body cover 37 Fixing rotating member 39 Heat insulating material 44 Fixing device cover 44b Sheet transport guide 47 Air gap 50 Heat insulating elastic member S Sheet

Continuation of front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/00 550 G03G 15/20 G03G 21/16-21/18

Claims (6)

(57) [Claims] 1. A fixing rotating member of a fixing device is covered with a heat insulating material.
In the electrophotographic apparatus in which the heat insulating material is further covered with a fixing device cover, the fixing device cover is fixed to the fixing front cover and after fixing.
It provided separately on the side cover, formed by allowing jam processing position or in the open Kukoto sheet respectively, an electrophotographic apparatus. 2. The electrophotographic apparatus according to claim 1, wherein a sheet conveyance guide section is provided integrally with said fixing device cover. 3. The electrophotographic apparatus according to claim 1, wherein an air gap is formed between the fixing device cover and the heat insulating material when the fixing device cover is closed. 4. The fixing device according to claim 1, wherein the fixing rotating member is formed by a roller, and when the fixing device cover is closed, the fixing device cover is positioned by abutting against a roller shaft of the roller. An electrophotographic apparatus according to the above. 5. The electrophotographic apparatus according to claim 1, wherein opening and closing of the fixing cover is linked with opening and closing of the apparatus main body cover. 6. The electrophotographic apparatus according to claim 5, wherein said apparatus main body cover is brought into contact with said fixing device cover via a heat insulating elastic member to partition between them.