JPH04217536A - Image formation device - Google Patents

Abstract

PURPOSE:To inhibit the abnormal elevation of the temperature in a device by carrying a decalcomania paper sheet for which the transcription of a toner image is finished, to a fixing apparatus without giving damage to the toner image, and by exhausting hot air generated from the fixing apparatus as well as a driving motor and the like, to the outside of the device. CONSTITUTION:A carrier belt 21, which is turned in the vicinity of the center of the carrier direction of a decalcomania paper sheet, and which is provided with a plurality of hole parts 211, is provided, while an inner guide plate 24A and a front side guide plate 24B are provided in front thereof and on the rear part thereof. An opening hole 244A is provided on the outside of the decalcomania paper sheet, on the inner guide plate 24A, while the opening hole 244A is connected with a suction hole 243A provided on the lower side of the carrier belt 21 through a suction route, so as to carry out suction by a fan motor 26.

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 in which a transfer sheet having undergone transfer is conveyed to a fixing device by a sheet conveying means.

0002

2. Description of the Related Art In an image forming apparatus, processes of charging, image exposure, and development are carried out on the peripheral surface of an image carrier, such as a rotating photoreceptor drum, and the toner images formed by the development are synchronously transported. transferred onto the transfer paper.

The transfer paper on which the toner image has been attached by the transfer is separated from the photosensitive drum, and the toner image is melted and fixed onto the transfer paper by a fixing device and then discharged from the apparatus.

The fixing device uses a heat roller that rotates with a heat source inside and a heat roller that follows and rotates while pressing against the heat roller, and the transfer paper with the toner image attached is placed between the heat roller and the pressure roller. Fixing is performed while being held and conveyed.

On the other hand, when transferring the toner image to the transfer paper, the transfer paper is temporarily in close contact with the circumferential surface of the photoreceptor drum, so the transfer paper is separated from the photoreceptor drum. In this state, it moves toward the fixing device in a biased state. Therefore, when the transfer/separation section of the photosensitive drum and the fixing device are disposed close to each other, a guide plate is provided between the transfer/separation section and the fixing device, and the transfer paper with the toner image attached is It is configured to move its back side along a guide plate. In order to guide the transfer paper that is urged and moves along the guide plate, for example,
As described in Specification No. 50, the guide plate is provided with an opening that forms an air flow path, and by suction by a fan motor, the transfer paper is guided so that it moves while keeping its back side in close contact with the guide plate. will be done.

[0006] Furthermore, when the transfer/separation section and the fixing device are located a certain distance apart, a paper conveyance means is provided between them. The paper conveying means includes a means of installing a rotating belt in the conveyance path, electrostatically adhering it to the belt that moves on the back side of the conveyor, and a means of conveying the paper by electrostatically attaching it to the belt that moves on the back side, and a means of conveying the paper by electrostatically attaching it to the belt that moves on the back side, and a method that uses a plurality of holes in the belt to form air flow paths. A means is used in which a section is provided to attract and convey the transfer paper to a moving belt body. For example, Japanese Patent Laid-Open No. 60-48861 discloses a technique related to this.

[0007]

Problems to be Solved by the Invention The outer surface of the fixing device is surrounded by heat insulating means or the like to prevent heat from dissipating to the outside. However, when used continuously for a long time, the fixing device begins to radiate heat to the outside. Further, the drive motor, control section, etc. also act as a heat source. Therefore, when used continuously for a long time, the temperature inside the image forming apparatus rises to a considerably high temperature. Photoreceptors such as OPC and Se are used as image carriers, but when these photoreceptors are exposed to high temperatures, their performance deteriorates and their lifespans are shortened.

[0008] The present invention provides an image forming apparatus having a function of preventing heat generation from a fixing device or a drive motor located at the back of an image forming apparatus by a sheet conveying path section to prevent an image carrier section from becoming hot. The purpose is to provide

[0009]

[Means for Solving the Problems] The present invention aims to achieve the above object, and the present invention provides a method for transferring a toner image formed on an image carrier onto a transfer paper, and then transporting the transfer paper to a paper. In an image forming apparatus in which paper is conveyed to a fixing device by a means for conveying paper, the means for conveying paper includes a rotating belt body having a large number of holes located near the center in the conveyance direction, and guide plates provided on both sides of the belt body. An opening hole is provided on the outer side of the transfer paper conveyed on the back side of the guide plate, and the opening hole is configured to be connected to a suction path provided inside the belt body and to be sucked in by a fan motor. The present invention provides an image forming apparatus characterized by the following features.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a sectional view of a main part of an image forming apparatus provided with a paper conveyance means of the present invention.

In the figure, reference numeral 11 denotes an image carrier, which is made of Se, OP.
This is a photoreceptor drum that rotates in a clockwise direction and has a photoreceptor such as C on the circumference of the drum. A charger 12, a static eliminator 13 for frame formation, an image exposure means 14, a developing means 15, a transfer electrode 16, a separation electrode 17, a separation claw 18, are provided at the peripheral edge of the photosensitive drum.
Cleaning means 19 and the like are provided, and image formation is performed through the following process. That is, after the rotating photosensitive drum 11 is uniformly charged by the charger 12, the static eliminator 13 irradiates light outside the screen frame to remove the charge outside the screen frame. Next, image exposure means 14, which scans and exposes the surface of the document, performs image exposure within the screen frame on photoreceptor drum 11 to form a latent image. The latent image on the photosensitive drum 11 is developed by the developing means 15, and toner is electrostatically attached to the latent image portion to form a toner image. The toner image on the photoreceptor drum 11 is brought into close contact with the transfer paper conveyed by the second paper feed roller 31 that rotates in synchronization so that the leading edge of the toner image matches the leading edge of the transfer paper.
The toner image is transferred onto the transfer paper by a transfer electrode operated from behind. The transfer paper that is in close contact with the photoreceptor drum 11 is neutralized and separated by the separation electrode 17, and the separation claws 18 work together to ensure the separation.

After the toner image has been transferred, the separated transfer paper is conveyed by a transfer paper conveyance device 20, which is a paper conveyance means, and the toner image is fused and fixed onto the transfer paper by a fixing device 32 using a heat roller type, and then transferred to the device. It is discharged outside. The fixing device 32 is surrounded by a heat insulating material, but when used continuously for a long time, it radiates heat to the outside as a heat source, and a drive system including a drive motor 33 is disposed above and behind the transfer paper conveyance device 20. Because of this, it becomes hot when used continuously for a long time. When high-temperature air near the fixing device 32 and drive motor 33 flows toward the photoreceptor drum 11, it increases the temperature of the photoreceptor.
Significantly degrades performance. The transfer paper conveyance device 20 to be described next has a structure that not only has good transfer paper conveyance performance using an intake conveyance belt but also sucks high-temperature air using an intake fan motor for conveyance. prevent an unreasonable increase in

2 and 3 both show the transfer paper conveyance device 20. FIG. 2 is a view from A in FIG. 1 when the transfer paper conveyance device 20 is viewed from above, and FIG. 3 is a view from B in FIG.
It is a sectional view of B. In both FIGS. 2 and 3, the left side of the drawing is the back side of the device, and the right side is the front side of the device.

The embodiment is an image forming apparatus that uses a center-based transfer paper conveyance system, in which transfer paper having a symmetrical paper width with the center C as the center is conveyed by a conveyor belt 21 provided at the center C portion. It will be done. The conveyor belt 21 is a belt body having a large number of small holes 211 with a belt width narrower than the minimum transfer paper width, and is stretched between a drive roller 22 and a driven roller 23, and the drive roller 22 is fixedly attached. A gear 222 fixed to the rear shaft end of the drive roller shaft 221
meshes with a drive gear (not shown), and the conveyor belt 21 rotates at the same circumferential speed as the circumferential speed of the photoreceptor drum 11 .

A back guide plate 24A and a front guide plate 24B, which are flat and have the same height and are wider than the transfer width, are provided on the back and front sides, slightly lower than the surface of the conveyor belt 21. The back guide plate 24A and the front guide plate 24B are each provided with a plurality of string-like protrusions 241 in the direction of movement of the transfer paper, and the transfer paper is attached to the string-like protrusions 24 that prevent it from being attracted.
Move as if gliding over 1. The back guide plate 24A is fixedly installed, and the front guide plate 24B uses the shaft 242B as a swing axis.
In the event of a jam, the structure is such that the jammed paper can be removed from the front side by pushing down as shown by the chain line in FIG. The fixed rear guide plate 24A extends to the bottom of the conveyor belt 21, and has an intake hole 243 in the portion below the conveyor belt 21.
A is provided. Further, a rectangular opening hole 244A is provided slightly outside the outer edge of the moving transfer paper, for example, on the back side at a distance of about 5 mm. Back guide board 24
On the back side of A, a box-shaped member 25 for forming an air flow is provided in an area including the intake hole 243A and the opening hole 244A, and an opening hole 251 is provided in the bottom surface of the box-shaped member 25. . Further, below the box-shaped member 25, an intake fan motor 26 is provided at a position very close to the bottom surface of the box-shaped member 25, as shown by the dotted line in FIG. It has a position and shape that almost matches the opening hole 251 of the shaped member 25, and is surrounded by the sealing member 245. Intake fan motor 2
6 is provided with a large number of fans 262, and when the intake fan motor 26 rotates clockwise and operates, it forms the air flow shown by the arrow in FIG. The exhaust gas is configured to be exhausted to the back side of the image forming apparatus through the provided hole.

The transfer paper separated after the transfer of the toner image is transported to the transfer paper transport device 20 having the structure described above.
When the leading edge of the transfer paper reaches the top surface of the transfer paper conveyance device 20, the center portion of the transfer paper is on the conveyance belt 21 that moves at the same speed as the transfer paper, and both side portions of the transfer paper are on the string-like protrusions 241. move as if sliding. Transfer paper has air intake hole 234
When the transfer paper reaches portion A, the small holes 211 of the conveyance belt 21 become under negative pressure, and the transfer sheet is attracted to the conveyance belt 21 and conveyed to the fixing device 32 . In this state, the intake hole 243A is covered with the transfer paper, so the suction by the intake fan motor 26 is concentrated on the opening hole 244A, and the hot air trapped at the back side is particularly strongly sucked while the transfer paper is being conveyed. will be done.

If a jam accident should occur during conveyance of the transfer paper, this is detected by a sensor (not shown), and the conveyance belt 21 is stopped. The operator can easily clear the jam by opening the front door (not shown) in response to the jam display and pushing down the front guide plate 24B held in a substantially horizontal position.

[0018]

Effects of the Invention The image forming apparatus of the present invention has a function of smoothly conveying the transferred transfer paper to the fixing device without damaging the toner image, and also has the function of smoothly conveying the transfer paper to the fixing device without damaging the toner image. By making this function function, hot air generated from the fixing device and drive rate is discharged from the back of the device, and the temperature inside the device does not become abnormally high, thereby providing an image forming device that can be used stably for a long time. It became a thing.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of essential parts of an image forming apparatus provided with a paper conveying means of the present invention.

FIG. 2 shows a plan view of the transfer paper conveying device of the present invention.

FIG. 3 shows a side sectional view of the transfer paper conveying device of the present invention.

[Explanation of symbols]

11... Photosensitive drum 16... Transfer electrode 17... Separation electrode
20... Transfer paper conveyance device 21... Conveyance belt
211...Small hole 22...Drive roller
23...Followed roller 24A...Back guide plate 24B...Front guide plate 241...String-like protrusion 243A
...Intake hole 244A...Opening hole
25... Box-shaped member 26... Intake fan motor
32...Fuser 33...Drive motor

Claims (1)

[Claims] Claims: 1. An image forming apparatus that transfers a toner image formed on an image carrier onto a transfer paper and then conveys the transfer paper to a fixing device by a paper conveyance means, wherein the paper conveyance means is located near the center in the conveyance direction. There is a belt body with a large number of holes that rotates in the belt body, and a guide plate provided on both sides of the belt body, and an opening hole is provided on the outer side of the transfer paper conveyed behind the guide plate. An image forming apparatus characterized in that the opening hole is connected to a suction path provided inside the belt body and is configured to be sucked in by a fan motor.