JP2001215824A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus where an accident due to heat generated in processing of jamming in a paper ejecting part is prevented and smooth ejection to a ejected paper stacking part is carried out. SOLUTION: In the image forming apparatus with an automatic both-side reversing mechanism to transfer images to both sides of transfer paper and provided with a branching claw 41 at the downstream of a fixing paper ejecting unit to direct the transfer paper to either the ejected paper stacking part 43 or the automatic both-side reversing mechanism, troubles (burns) caused by heat when processing the jamming outside the fixing paper ejecting unit is prevented since heat insulating material 92, that is, a fiber flocked sheet provided with heat resistant fibers on its surface, for example, is provided on an exterior wall surface of the fixing paper ejecting unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electrophotographic image forming apparatus, and more particularly, to the structure of a fixing and discharging unit.

[0002]

2. Description of the Related Art An automatic double-sided reversing mechanism for transferring an image to both sides of a transfer sheet is provided, and a transfer sheet is directed downstream of a fixing sheet discharging unit to either a sheet discharge stack section or an automatic double-sided reversing mechanism. An image forming apparatus having a claw includes a branch discharge unit including a branch claw.

[0003] The branch discharge unit is openable and closable with respect to the apparatus main body. When a jam occurs in the vicinity of the branch discharge unit, the unit can be opened to remove the jammed paper, but is normally closed. In other words, the discharge port of the fixing discharge unit is not normally exposed to the outside.

[0004]

In the above-described image forming apparatus having an automatic double-sided reversing mechanism and a branch discharge unit for covering the fixing discharge unit, the thermal energy generated from the fixing device constituting the fixing discharge unit If the user tries to clear the jam by opening the branch ejection unit when jam occurs, there is a danger of burns because the area including the ejection outlet is hot. .

On the other hand, an ordinary single-sided image forming type image forming apparatus which does not have an automatic double-sided reversing mechanism does not have such a fear because it does not have a branch discharge unit. Smooth paper discharge is required.

The present invention has been made on the basis of such a background, and an image forming apparatus capable of preventing an accident due to heat at the time of jam clearance in a paper discharge unit and enabling smooth paper discharge to a paper discharge stack unit. The purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided an automatic double-sided reversing mechanism for transferring an image to both sides of a transfer sheet, and a downstream side of a fixing discharge unit. In an image forming apparatus having a branch claw for directing a transfer sheet to one of a sheet discharge stack unit and an automatic double-sided reversing mechanism, a heat insulating material is provided on an outer wall surface of the fixing sheet discharge unit.

[0008] In order to achieve the above object, a second aspect is provided.
According to a first aspect of the present invention, in the image forming apparatus according to the first aspect,
The heat insulating material is a flocked sheet having heat-resistant fibers on the surface.

In order to achieve the above object, a third aspect of the present invention is provided.
The described invention is characterized in that, in an image forming apparatus of a type in which an image is transferred to one side of a transfer sheet, a heat-resistant film-like sheet is provided on an outer wall surface of a fixing sheet discharging unit.

According to the first and second aspects of the present invention, since a heat insulating material, specifically, a flocked sheet having, for example, heat-resistant fibers on the surface thereof is provided on the outer wall surface of the fixing and discharging unit, a jam outside the fixing and discharging unit is provided. During the treatment, there is no risk of trouble (burn) due to heat.

According to the third aspect of the present invention, in the image forming apparatus of the type in which an image is transferred onto one side of a transfer sheet, the heat-resistant film-like sheet is provided on the outer wall surface of the fixing and discharging unit. As a result, the slip of the transfer paper is improved, and the transfer paper is efficiently stacked on the discharge stack portion.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a full-color printer having an automatic duplex reversing mechanism. In FIG. 1, reference numeral 1 denotes a flexible photoreceptor belt which is a belt-shaped image carrier. The photoreceptor belt 1 is bridged between rotating rollers 2 and 3, and is driven by the rotation of the rotating roller 2. It is transported in the direction of the middle arrow A (clockwise).

In the figure, reference numeral 4 denotes a charging charger as charging means for uniformly charging the surface of the photoreceptor belt 1;
This is a laser writing system unit that is an electrostatic image exposure unit. Reference numeral 6 in the figure denotes a color developing device in which four developing devices having yellow, magenta, cyan, and black developers (toners) described later are integrally formed.

Further, reference numeral 10 in the figure denotes an intermediate transfer belt constituting an intermediate transfer member. The intermediate transfer belt 10 is provided between rotating rollers 11 and 12 and is driven by rotating the rotating roller 11. The sheet is conveyed in the middle arrow B direction (counterclockwise).

The photosensitive belt 1 and the intermediate transfer belt 10
Are in contact with the rotating roller 3 of the photosensitive belt 1.
On the intermediate transfer belt 10 side of the contact portion, a bias roller 13 having conductivity is in contact with the back surface of the intermediate transfer belt 10 under predetermined conditions.

A paper feed cassette 17 is provided at the inner bottom of the apparatus, and a reversing device 60, which is a component of a two-sided reversing device, is provided below the sheet feeding cassette 17. Further, a fixing device 80 is provided on the downstream side of the intermediate transfer belt 10 in the transfer paper transport direction, and a branch paper discharge unit 40 is further provided on the downstream side thereof.

A vertical transport section 50 is provided between the branch discharge unit 40 and the reversing device 60.
The branch discharge unit 40, the transport unit 50, and the reversing device 60
The three-sided unit constitutes a two-sided reversing device. The branch discharge unit 40 can be opened and closed around a fulcrum 40a.

A first discharge roller pair 81 is provided near the downstream side of the fixing device 80, and a fixing discharge unit 82 is constituted by the fixing device 80 and the first discharge roller pair 81. Further, the branch discharge unit 40 is provided with a branch claw 41 so as to approach the fixing discharge unit 82.

Other configurations will be described together with the following image forming operation. After the photoreceptor belt 1 is uniformly charged by the charging charger 4, it is scanned and exposed by the laser writing system unit 5 based on image information, and an electrostatic latent image is formed on the surface.

Here, the image information to be exposed is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black color information, and is generated by a semiconductor laser (not shown) based on this information. Laser beam L
Is obtained by scanning and optical path adjustment by an optical device not shown.

The electrostatic latent image formed here is developed in a single color with predetermined yellow, cyan, magenta, and black toners by a rotary type color developing device 6, and each color image is formed on the photosensitive belt 1. Are sequentially formed.

The photoreceptor belt 1 rotates in the direction of arrow A in FIG.
Each monochromatic image formed on the intermediate transfer belt 10 is rotated in the direction of arrow B in FIG.
For each of the single colors of yellow, cyan, magenta, and black, the image is sequentially transferred by a predetermined transfer bias applied to the bias roller 13.

The yellow, cyan, magenta, and black images superimposed on the intermediate transfer belt 10 are transported from a paper cassette 17 to a transfer section via a paper feed roller 18, a transport roller pair 19, and a registration roller pair 20. The transfer roller 14 collectively transfers the transfer paper onto the transferred transfer paper.

After the transfer is completed, the transfer paper is fixed by a fixing device 80 to complete a full-color image, and is discharged out of the device or sent to a double-side reversing device, where the image forming, transfer, and fixing processes for the second surface are performed. Performed in the same manner as the first surface.

The transfer path of the transfer sheet discharged from the fixing sheet discharge unit 82 is switched by the branch claw 41. The transfer paper to be discharged out of the apparatus is the second discharge roller pair 4
2 and are stacked in the paper discharge stacking section 43.

The transfer paper on which the second surface is printed passes under the discharge stack 43 by the branching pawl 41 and passes through the transport roller pair 4.
4. The sheet passes through the guide plate 45 and is transported to the transport unit 50.
In the transport section 50, the transfer paper is guided to the reversing device 60 by the transport roller pair 52 and the guide plate 51.

In the reversing device 60, the transfer paper is transported from the rear to the front (operator side) by the guide plate 61 and the transport roller 62, and the direction is changed by the transport guide plate 65 and the reverse roller 63. The transported roller is transported in the direction of the transport roller 64 by the reverse rotation of the reversing roller 63, the transport path 70, the transport roller pair 19, and the registration roller pair 20 provided on the front side of the sheet cassette 17.
After that, the sheet is discharged to the sheet discharge stack section 43 through the same process as the first surface.

In the figure, reference numeral 15 denotes a cleaning device including a cleaning blade which is always in contact with the photoreceptor belt 1 and cleans toner on the photoreceptor belt 1, and a waste toner collecting container, and 16 denotes an intermediate transfer belt. In the cleaning device 10, the cleaning blade of the cleaning device 16 is held at a position separated from the surface of the intermediate transfer belt 10 during the image forming operation, and after the formed image is transferred onto the above-described transfer paper, the intermediate transfer belt 10 Contacted to the surface.

The photosensitive belt 1, the charging charger 4, the intermediate transfer belt 10, the cleaning devices 15, 16
Are integrally formed as a process cartridge 31, and the waste toner collecting container 22 is incorporated in the process cartridge 31 in a replaceable manner. The case exterior portion of the process cartridge 31 on the roller side below the second registration roller 23 also has a function as a transfer paper transport guide.

The waste toner scraped off from the intermediate transfer belt 10 by the cleaning blade is conveyed by the auger 21 provided in the cleaning device 16 toward the front of the drawing, and further provided on the front side of the process cartridge 31 as shown in FIG. Are conveyed to the waste toner collecting container 22 by the conveying unit in which is omitted.

When a predetermined amount or more of waste toner is stored in the waste toner collecting container 22, the process cartridge 31 is replaced with a new one.
1 is extended.

The front frame 8 is rotatable to open and close.
Roller above the pair of registration rollers 23, transfer roller 1
4 and the like are held. When the front frame 8 is opened, the transfer paper transport path is exposed, and the jam processing can be easily performed. At this time, the other image forming units are stationary, and no troubles such as scattering or leakage of toner occur.

FIG. 2 is an overall configuration diagram of a full-color printer of a type in which an image is transferred to one side of a transfer sheet (that is, it does not have an automatic double-side reversing mechanism). In the case of this printer, a fixing and discharging unit 8 including a fixing device 80 and a pair of discharging rollers 81
On the downstream side of 2, only the paper discharge stack section 43 is provided. Further, the body frame 9 is not provided with a double-sided reversing device as shown in FIG. Other configurations are the same as those in FIG.

FIGS. 3A and 3B are perspective views of the vicinity of the fixing device of the printer shown in FIG. 1, wherein FIG. 3A is a perspective view of the front side of the exterior cover, and FIG. 3B is a perspective view of the back side of the exterior cover. Although an exterior cover 91 is covered above the fixing device 80,
If the exterior cover 91 becomes hot due to heat radiation from the fixing device 80, there is a risk of burns when a user touches the outside of the exterior cover 91.

Therefore, the outer wall surface of the fixing and discharging unit 82,
Specifically, as shown in (B), a heat insulating material 92 is attached to the inner surface of the outer cover 91 so that heat is not transmitted to the outside. The heat insulating material 92 is composed of, for example, a flocking sheet having heat-resistant fibers on the surface.

FIGS. 4A and 4B are perspective views of the branch discharge unit, where FIG. 4A is a front perspective view and FIG. 4B is a rear perspective view. When the heat insulating material 92 is attached not only to the exterior cover 91 on the fixing device 80 side but also to the inner surface of the case of the branch discharge unit 40 (see FIG. 8B), the heat insulating effect is further increased.

FIG. 5 is a view showing an example in which a heat insulating material is provided below the first sheet discharging roller pair of the fixing sheet discharging unit. As shown in this figure, a heat insulating material 92 is provided below the first discharge roller pair 81.
Is provided, this part can also be insulated.

FIG. 6 is a top perspective view of the printer shown in FIG. In the case of this type of printer, the printer does not have an automatic double-sided reversing device and, therefore, does not have the branch discharge unit 40, and thus does not have the above-described disadvantages. A heat-resistant film-like sheet 93 is provided on the inner surface. The upper surface of the transfer paper comes into contact with the sheet 93 and becomes slippery.
The transfer paper is discharged smoothly.

[0039]

According to the first and second aspects of the present invention, a heat insulating material, specifically, a flocking sheet having, for example, heat-resistant fibers on the surface thereof is provided on the outer wall surface of the fixing and discharging unit. Troubles (burns) due to heat can be prevented when clearing the jam outside the unit.

According to the third aspect of the present invention, in the image forming apparatus of the type in which an image is transferred onto one side of a transfer sheet, a heat-resistant film-like sheet is provided on the outer wall surface of the fixing and discharging unit. With this sheet, the transfer paper slides well, and the transfer paper can be efficiently stacked on the discharge stack unit.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a full-color printer having an automatic duplex reversing mechanism.

FIG. 2 is an overall configuration diagram of a full-color printer that transfers an image to one side of a transfer sheet.

FIG. 3 is a perspective view of the vicinity of a fixing device of the printer shown in FIG.

FIG. 4 is a perspective view of a branch discharge unit.

FIG. 5 is a diagram illustrating an example in which a heat insulating material is provided below a first discharge roller pair of the fixing discharge unit.

6 is an upper perspective view of the printer shown in FIG. 2;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoreceptor belt 4 charging charger 5 laser writing system unit 6 color developing device 10 intermediate transfer belt 13 bias roller 14 transfer roller 17 paper feed cassette 40 branch discharge unit 41 branch claw 42 second discharge roller pair 43 discharge stack Unit 50 Conveying Unit 60 Reversing Device 80 Fixing Device 81 First Discharge Roller Pair 82 Fixing Discharge Unit 91 Exterior Cover 92 Heat Insulating Material 93 Heat Resistant Film Sheet

Claims (3)

[Claims] An automatic double-side reversing mechanism for transferring an image to both sides of a transfer sheet, and a branch for directing the transfer sheet to one of a discharge stack unit and an automatic double-side reversing mechanism downstream of a fixing sheet discharging unit. An image forming apparatus having a claw, wherein a heat insulating material is provided on an outer wall surface of a fixing and discharging unit. 2. The image forming apparatus according to claim 1, wherein the heat insulating material is a flocking sheet having heat-resistant fibers on a surface. 3. An image forming apparatus in which an image is transferred onto one side of a transfer sheet, wherein a heat-resistant film-like sheet is provided on an outer wall surface of a fixing sheet discharging unit.