JP2002268522A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device for which the temperature rise of transfer remaining toner inside a cleaner is suppressed without enlarging a fan. SOLUTION: The image formation device is provided with a photosensitive drum 1, the cleaner 15 for cleaning the transfer remaining toner on the surface of the photosensitive drum 12, a toner discharging screw 19 for carrying the transfer remaining toner inside the cleaner 15 to the outside of the cleaner 15 and a fixing device 14 provided with a heat roller 20. For the representative constitution of the image formation device, an intake fan 22 for sucking the outdoor air in a longitudinal direction between the cleaner 15 and the fixing device 14 and an air duct 21 arranged so as to make an air flow formed by the intake fan 22 pass between the fixing device 14 and the cleaner 15 are provided and an air guide 30 connected to the air duct 21 for blowing the air after being made to pass through the duct to the outer wall of the cleaner 15 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine and a printer.

2. Description of the Related Art Conventionally, a photosensitive drum, a cleaner for cleaning transfer residual toner on the surface of the photosensitive drum, a toner discharging screw for transporting the transfer residual toner inside the cleaner to the exterior of the cleaner, and a heat source are provided in a conventional apparatus. An image forming apparatus including a fixing device having a roller is generally used. In recent years, such an electrophotographic apparatus has been demanded to operate at high speed and to be downsized. It is planned to arrange them. However, when both are arranged close to each other in this manner, the temperature around the photosensitive drum increases due to heat generated in the fixing device. In particular, when the transfer residual toner contained in the cleaner is discharged to the outside of the cleaner, the temperature of the transfer residual toner around the discharge screw is increased by the heat, and the transfer residual toner may aggregate around the screw.

As described above, when the transfer residual toner aggregates around the discharge screw, the conveying efficiency of the screw is reduced, and in the worst case, the rotation of the screw is locked.
The drive mechanism of the apparatus body is seriously damaged.

[0003] In order to solve such a problem,
There has been proposed a device in which an air curtain is formed between a photoconductor and a fixing device so that heat generated in the fixing device is not transmitted to the photoconductor.

[0004]

However, when the air flow of the air curtain cannot be sufficiently secured (for example, when the size of the fan is increased to secure the air flow of the air curtain, the noise level of the apparatus body is deteriorated), the cleaner is used. It is difficult to suppress the temperature rise of the transfer residual toner inside.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of suppressing a rise in temperature of transfer residual toner inside a cleaner without increasing the size of a fan.

[0006]

In order to solve the above-mentioned problems, a typical configuration of an image forming apparatus according to the present invention comprises a photosensitive drum, a cleaner for cleaning transfer residual toner on the surface of the photosensitive drum, and In an image forming apparatus including a toner discharging screw for transporting transfer residual toner inside the cleaner to the outside of the cleaner and a fixing device having a heat roller, external air is sucked in a longitudinal direction between the cleaner and the fixing device. And a duct arranged so that an air flow formed by the intake fan passes between the fixing device and the cleaner. The duct is continuous with the duct, and the air after passing through the duct is supplied to an outer wall of the cleaner. It is characterized by having an air guide for spraying the air.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

[0008] As shown in FIG.
Rotating cylindrical photosensitive drum 1 extending in the direction perpendicular to the paper surface
Is uniformly charged by the charger 2.
The laser scanner 3 modulates an image signal input to the image forming apparatus into an on / off state of a laser beam. A laser beam 4 emitted from the laser scanner 3 is projected onto the charged surface and an electrostatic latent image is formed on the surface of the photosensitive drum 1. Is formed.

When the latent image reaches the developing site where the developing device 5 is located as the photosensitive drum 1 rotates, the developing device 5
The latent image is visualized by the toner supplied from above to the latent image to form a toner image. As the photosensitive drum 1 further rotates, the toner image is transferred to the photosensitive drum 1 and the transfer charger 6.
Arrive at the opposite transcription site.

At the same time, a transfer material is supplied to the transfer portion via the registration roller 11 in synchronization with the toner image. Next, a transfer bias is applied to the transfer charger 6, and the toner image on the photosensitive drum side is transferred (transferred) to the transfer material.

After the transfer is completed, a separation current is applied to the transfer material from a separation charger 12, and the transfer material is separated from the photosensitive drum 1, reaches a fixing device 14 via a transport path 13, and a toner image is transferred to the transfer material. After fixing and fixing, it is discharged outside the machine.

During transfer, the photosensitive drum 1 does not transfer to the transfer material.
A small amount of the transfer residual toner remaining on the surface proceeds as it is, reaches the position of the cleaner 15, and is removed by the cleaning blade 16. Further, the residual charges are erased by the pre-exposure lamp 17, and the photosensitive drum is ready for the next image forming step.

On the other hand, the transfer residual toner removed by the cleaning blade 16 falls in the cleaner container and accumulates in the lowermost portion 18 in the container. Further, a toner discharge screw 19 for discharging the transfer residual toner to the outside of the cleaner container is arranged at the lowermost portion 18, and the transfer residual toner is conveyed by the rotation of the toner discharge screw 19. In the figure, the toner discharging screw 19 is configured to transport the transfer residual toner from the near side to the rear side toward the paper surface, and discards the transported residual toner.

The fixing device 14 heats the heat roller 20 to a little less than 200 degrees in order to thermally fix the toner image on the transfer material. Therefore, the periphery of the fixing device 14 is exposed to a very high temperature environment, and the influence thereof is affected by the photosensitive drum 1,
Covers 15 cleaners.

An air duct 21 is provided between the fixing device 14 and the cleaner 15. Arrange the intake fan 22 on the front side of the device,
Air is allowed to flow in the longitudinal direction of the device from the air inlet 23 of the air duct 21. This air flows in the longitudinal direction of the air duct 21 and also flows into the vertical duct 24, and is discharged from the air duct outlet 25 as shown by the arrow in the drawing. Thus, the influence of the temperature from the fixing device 14 on the cleaner 15 is reduced.

As shown in FIG. 2, the air duct 21 is provided with an air guide 30 and a diffusion prevention plate 31 continuously at an air discharge port 25 thereof. The air guide 30 is configured to guide the air passing through the vertical duct to the cleaner 15 side, and the end of the air guide 30 is extended to the vicinity of the cleaner. In this way, the air duct 21 is simply
In addition to the arrangement for forming the air curtain for heat insulation between the cleaner and the cleaner 15, the air is directly guided to the outer wall of the cleaner container, so that the temperature rise of the cleaner portion can be efficiently reduced. As a result, it is not necessary to use a large fan for reducing the temperature rise of the cleaner 15, so that the intake fan 22 can be downsized and the noise level of the apparatus main body can be reduced.

The air guide 30 has a structure in which the direction of the air flow is bent by about 90 ° from the air duct discharge port 25 to the cleaner 15.
Air is easily diffused at the bent portion. for that reason,
The diffusion prevention plate 31 is provided at a position facing the bent portion to prevent a decrease in the flow rate of the air flow.

The air guide is configured so that air is intensively blown to an outer wall portion 41 corresponding to an adjacent portion 40 between the toner discharging screw 19 and the inner wall of the cleaner. As a result, there has been a problem that the transfer residual toner aggregates around the toner discharging screw due to the heat generated by the temperature rise inside the cleaner, but the aggregation of the transfer residual toner around the toner discharging screw is more effectively avoided. can do.

The structures of the intake fan 22 and the air duct 21 are as described above. Here, the partition member 50 in the air duct will be further described.

Dry ice or the like was placed in front of the intake fan 22 and the actual flow of air flowing into the air duct 21 was observed. Without the partition member 50, the air that has flowed in from the intake fan descends before much of it (depending on the air volume of the intake fan, but with a fan of common sense size) does not reach the far side in the longitudinal direction. Then, the air was discharged from the air duct outlet 25 through the vertical duct 24.

Therefore, as shown in FIG.
The air was reliably discharged from the deep side of the air duct outlet 25 in the longitudinal direction. Further, a hole 51 is formed near the center of the partition member 50, and air is discharged also near the center in the longitudinal direction. Thus, the air that has flowed in from the intake fan 22 can be discharged from the air duct discharge port 25 in all longitudinal directions.

Here, suppose that the surface of the cleaner adjacent to the screw for discharging toner inside the cleaner is largely divided into three front,
When the area was divided into middle and deep areas, when the partition member 50 was not provided, the temperature was increased from the front to the deep as shown in FIG.

On the other hand, when the partition member 50 was incorporated, the above-mentioned tendency to increase the temperature was improved so that the temperature became uniform before, during, and after being placed as shown in FIG.

Although the results shown in FIG. 5 can be predicted to some extent by simulation or the like, actually, the position of the fan-side starting end, the position of the other end, the size of the hole near the center, etc. of the partition member 50 are experimentally considered. It was decided by mistake. Looking at the ratio of the amount of air blown to the outside of these measurement points (on the side of the cleaner outer wall), the front: middle: depth is approximately 1.5:
Measurement data of 2.5: 6 was obtained.

In the image forming apparatus used in this experiment, since the temperature rise tendency before the air duct was introduced was such that the front side was low and the back side was high, the above-mentioned air volume ratio was obtained. Equipment has the highest temperature rise tendency,
Next, if the depth is high and the front shows a tendency to be low, the hole near the center of the partition member 50 is enlarged, the air volume ratio in the longitudinal direction of the cleaner is increased, and the reduction in the temperature rise amount in that portion is increased. It is also possible to give priority.

As described above, by adopting a shape in which air is selectively blown as required, the amount of temperature rise on the back side of the apparatus can be reduced without increasing the size of the fan.

[0027]

As described above, an intake fan for sucking outside air, a duct arranged so that an air flow formed by the intake fan passes between a fixing device and a cleaner, and a continuous Then, an air guide for blowing air after passing through the duct to the outer wall of the cleaner was provided. Thereby, the temperature rise of the cleaner can be suppressed efficiently.

In the longitudinal direction in the duct,
A partition member was provided in the duct in order to give weight to the amount of air passing through the unit area. Thus, air can be selectively blown to a portion where the temperature rise level is high in the longitudinal direction in the cleaner container, and the output of the intake fan can be minimized.

Further, air is intensively blown in the vicinity of the toner discharging screw, where the adverse effect of the temperature rise is expected most in the cleaner. This makes it possible to efficiently reduce the temperature rise inside the cleaner.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a main part of an image forming apparatus according to an embodiment.

FIG. 2 is an enlarged view of a main part near an air duct outlet.

FIG. 3 is a partial sectional view of an air duct.

FIG. 4 is a diagram illustrating a temperature rising state when a partition member is not provided.

FIG. 5 is a diagram showing a temperature rising state when a partition member is provided.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charger 3 laser scanner 4 laser beam 5 developing device 6 transfer charger 11 registration roller 12 separation charger 13 transport path 14 fixing device 15 cleaner 16 cleaning blade 17 Pre-exposure lamp 18… Bottom part 19… Toner discharge screw 20… Heat roller 21… Air duct 22… Intake fan 23… Intake port 24… Vertical duct 25… Air duct discharge port 30… Air guide 31… Diffusion prevention plate 40… Proximity part 41… Outer wall part 50… Partition member 51… Hole

Claims (3)

[Claims] 1. A fixing device comprising: a photosensitive drum; a cleaner for cleaning transfer residual toner on the surface of the photosensitive drum; a toner discharging screw for transporting transfer residual toner inside the cleaner to the outside of the cleaner; An image forming apparatus comprising: a suction fan that sucks outside air in a longitudinal direction between a cleaner and a fixing device; and an air flow formed by the suction fan passes between the fixing device and the cleaner. And an air guide that is continuous with the duct and that blows air after passing through the duct to an outer wall of the cleaner. 2. The image forming apparatus according to claim 1, wherein a partition member is provided in the duct in order to give weight to an air volume of air passing per unit area in a longitudinal direction in the duct. . 3. The image according to claim 1, wherein the air guide has a shape in which air is intensively blown to an outer wall portion corresponding to a portion where the toner discharging screw and a cleaner inner wall are close to each other. Forming equipment.