JPH0863057A - Color image forming device - Google Patents

Abstract

PURPOSE: To prevent the overheating of a photoreceptor caused by the heat generation of the light source of an exposure optical system in the photoreceptor, even if the exposure optical system is consecutively lighted for a long time. CONSTITUTION: An air sucking hole 10W1 and an air intake hole 30W1 are made on the flange 10A of one end part of a photoreceptor drum 10 and the side surface of a cartridge 30 respectively. The other end part, of the drum is opened, an exhaust hole 40W1 is made on a substrate 40 and a propeller fan F1 is installed outside the exhaust hole 40W1. Such a constitution that the propeller fan F1 is rotated with the signal of a temperature sensor provided in the drum and air outside the drum which is sucked into the sucking hole 10W1 through the air intake hole 30W1 is forcibly discharged from the exhaust hole 40W1, to form a flow of air between the inside face of the drum and the exposure optical system and radiate the heat generated by it outside a device is adopted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus for forming a color image by superposing toner images formed by a plurality of charging means, an image exposing means and a developing means, and in particular, the plurality of image exposing means. The present invention relates to a color image forming apparatus of a type in which an image forming body is included.

[0002]

2. Description of the Related Art Generally, as an image exposure means, an exposure optical system using a self-ox lens (trade name) as an image forming optical system and an LED as a light source is used. Due to long-time lighting, the amount of heat generated accumulates inside the image forming body, degrading the performance of the photoreceptor layer and toner,
Further, the thermal expansion may change the resist function.

Conventionally, in order to prevent this phenomenon, a heat pipe is embedded in a support for supporting the exposure optical system to radiate the heat generated by the LED to the outside.

[0004]

However, although the installation of the heat pipe causes an increase in cost and structural restrictions, its heat radiating action is mainly intended for the support and the image formation is performed. It cannot be said that it is sufficient as a wide-range cooling means including the body.

As a result of solving and improving this point, the present invention provides
An object of the present invention is to provide a color image forming apparatus capable of efficiently forming a high-quality image without causing deterioration of the image forming function even when used for a long time by efficiently cooling a wide area in the image forming body. It is a thing.

[0006]

The above object is to repeatedly form a toner image on the image forming body by repeating charging of the image forming body by the charging means, image exposure by the image exposing means, and development by the developing means. Then, in the color image forming apparatus for performing the batch transfer to the transfer material, the image exposing unit is enclosed in the image forming body and cooled by an air flow penetrating the image forming body. (1st invention), charging of the image forming body by the charging means, image exposure by the image exposing means, and development by the developing means are repeated to form toner images on the image forming body in a superimposed manner, and then collectively transferred to a transfer material. In the color image forming apparatus, the image exposing unit is enclosed in the image forming body and is cooled by an air flow circulating in the image forming body. It is achieved by 2 invention).

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of each embodiment of the present invention, the structure of a color image forming apparatus common to each invention will be described with reference to FIGS.

Reference numeral 10 denotes a drum-shaped image forming body, that is, a photosensitive drum, which has a transparent conductive layer on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin, and a-Si or organic material on the transparent conductive layer. A photosensitive layer (OPC) is provided.

A flange 10A at one end of the photosensitive drum 10 has a guide pin 30 provided in a cartridge 30 described later.
The flange 10B at the other end is supported by P, and the flange 10B at the other end is fitted onto a plurality of guide rollers 40R provided on the substrate 40 of the apparatus main body to mesh the outer gear 10G with the drive gear 40G. Rotated clockwise with the layers grounded.

Reference numeral 11 denotes a scorotron charger, which is a photosensitive drum 10.
The above-mentioned organic photoconductor layer is charged by a grid held at a predetermined potential and corona discharge by a discharge wire to give a uniform potential to the photoconductor drum 10.

Reference numeral 12 denotes L arranged in the axial direction of the photosensitive drum 10.
ED12A and self-ox lens 12B as an imaging element
In the exposure optical system configured by, the image signals of the respective colors read by the separate image reading device are sequentially taken out from the memory and input to the respective exposure optical systems 12 as electric signals.

Each of the above-mentioned exposure optical systems 12 is a cylindrical support member fixed to the substrate 40 of the apparatus main body by screwing.
It is mounted on the photosensitive drum 10 and is housed inside the substrate of the photosensitive drum 10.

Numerals 13Y to 13K are developing units for accommodating the yellow (Y), magenta (M), cyan (C) and K (black) developers, respectively, and each has a predetermined gap with respect to the peripheral surface of the photosensitive drum 10. Development sleeve 13 that keeps the same and rotates in the same direction
It has 0.

Each of the developing devices is in a non-contact state by applying a developing bias voltage to the electrostatic latent image formed on the photosensitive drum 10 formed by the charging by the charging device 11 and the image exposure by the exposure optical system 12 described above. Reverse development with.

Next, the process of the color image forming apparatus in this apparatus will be described.

The original image is temporarily read as an image signal for each color of Y, M, C and K from an image read by an image pickup device or an image edited by a computer in an image reading apparatus separate from this apparatus. Stored and stored in memory.

When the photoconductor drive motor is started by the start of image recording, the drive gear 40G is rotated to rotate the photoconductor drum 10 clockwise, and at the same time, the photoconductor is charged by the charging device 11 (Y). Application of electric potential to the drum 10 is started.

After the photoconductor drum 10 is applied with an electric potential,
In the exposure optical system 12 (Y), the exposure by the electric signal corresponding to the first color signal, that is, the yellow (Y) image signal is started, and the yellow (Y) of the original image is formed on the photosensitive layer on the surface by the rotational scanning of the drum. ) Form an electrostatic latent image corresponding to the image.

The latent image is reversely developed by the developing device 13 (Y) with the developer on the developing sleeve in a non-contact state, and a yellow (Y) toner image is formed according to the rotation of the photosensitive drum 10.

Next, the photosensitive drum 10 is the yellow (Y)
An electric potential is further applied to the toner image of No. 1 by the charging action of the charger 11 (M), and exposure is performed by an electric signal corresponding to the second color signal of the exposure optical system 12 (M), that is, the image signal of magenta (M). Then, non-contact reversal development by the developing device 13 (M) sequentially forms a magenta (M) toner image on the yellow (Y) toner image.

By the same process, a cyan (C) toner image corresponding to the third color signal is further generated by the charger 11 (C), the exposure optical system 12 (C) and the developing device 13 (C), and the charger also. 11 (K), exposure optical system 12 (K) and developing unit 13
By (K), a black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 10 within one rotation.

Photoreceptor drum 10 by each of these exposure optical systems
The exposure of the photosensitive layer is carried out from the inside of the drum through the above-mentioned transparent substrate. Therefore, the second, third and fourth
The exposure of the image corresponding to the first color signal is performed without any influence of the toner image previously formed, and an electrostatic latent image equivalent to the image corresponding to the first color signal can be formed. It will be possible. The stabilization of the temperature inside the photosensitive drum 10 and the prevention of the temperature rise due to the heat generation of each exposure optical system 12 use a material having good thermal conductivity for the supporting member 20, and use a heater 201 when the temperature is low, When the temperature is high, it can be suppressed to the extent not hindering by taking measures such as radiating heat to the outside through an air flow penetrating the image forming bodies of the present invention described later or an air flow circulating between the image forming bodies. it can. Further, during the developing action by each developing device, a developing bias in which a direct current or an alternating current is applied to the developing sleeve 130 is applied respectively, and jumping development is performed by the one-component or two-component developer accommodated in the developing device, thereby making it transparent. Non-contact reversal development is performed on the photosensitive drum 10 whose conductive layer is grounded.

Thus, the color toner image formed on the peripheral surface of the photosensitive drum 10 is transferred to the transfer paper which is conveyed from the paper feed cassette 15 in the transfer device 14A and is fed synchronously by the driving of the timing roller 16. It

The transfer paper on which the toner image has been transferred is a static eliminator.
In 14B, the charge is removed and the toner is separated from the peripheral surface of the drum. After the toner is fused in the fixing device 17, the toner is discharged via the paper discharge roller 18 onto the tray above the device.

On the other hand, the photosensitive drum 10 from which the transfer paper has been separated removes and cleans the residual toner in the cleaning device 19 to continue the formation of the toner image of the original image, or temporarily stops the toner image of the new original image. Formation.

The photosensitive drum 10, each charging device 11, each developing device 13, and the cleaning device 19 are housed in a cartridge 30 and integrated with each other, without exposing the image exposing means to a load or impact, and exposing optical means. The support member (20) having the system (12) is left so that it can be attached to and detached from the main body of the apparatus. The structure in which the supporting member 20 is left at the time of attachment / detachment is such that the lead wire 203 and the exposure optical system 12 for operating the cooling means, the heater, and the LED 12A of the present invention are attached to the supporting member 20 in spite of the rotation of the photoconductor and the attachment / detachment of the photoconductor. It has the feature that it can be fixed.

(Embodiment 1) An embodiment of the first invention of the present invention will be described with reference to FIGS.

The exposure optical system 12 in each drawing is shown by a cross section in the direction of the arrow in FIG.

In the example shown in FIG. 2, the aforementioned flange is used.
10A is provided with a plurality of intake holes 10W1 on the peripheral edge thereof, and a plurality of air intake holes 30W1 slightly larger than the intake holes 10W1 are opened on the side surface of the cartridge 30 facing the intake holes 10W1.

On the other hand, the substrate 40 has a plurality of exhaust holes 40W1 formed around the fixed supporting member 20.
A propeller fan F1 is installed behind 40.

The propeller fan F1 is a photosensitive drum 10
The rotation of the sensor detects the internal temperature, and the suction action of the sensor causes the air outside the cartridge 30 to be sucked into the intake hole 10W1 through the air intake hole 30W1. An air flow in the axial direction of the drum is formed in a cylindrical space between the outside and the outside.

The above-mentioned air flow absorbs the amount of heat generated by passing through the outside of the exposure optical system 12, and is discharged to the outside of the apparatus from the exhaust hole 40W1 of the substrate 40 through the duct D by the exhaust action of the propeller fan F. To do.

Therefore, the photosensitive drum 10 and the exposure optical system
No. 12 will prevent excessive temperature rise and will always be kept in an appropriate temperature range where the performance can be fully exhibited.

Since the dust and the like are filtered by the filter f1 provided in the air intake hole 30W1 of the cartridge 30, the air flow sucked into the photosensitive drum 10 also has the effect of cleaning the self-ox lens 12B. There is.

On the other hand, in the example shown in FIG. 3, the flange 10A is provided with a plurality of intake holes 10W2 around the shaft portion, and the side surface of the cartridge 30 opposed to the flange 10A is slightly smaller than the intake holes 10W2. Large multiple air intake holes
30W2 is opened.

Further, the supporting member 20 has an axial center of a hollow portion 20A.
The exposure optical system 12 described above is provided on the peripheral surface of the hollow portion 20A.
Exhaust hole that protrudes the LED 12A of the
A propeller fan F2 is installed behind 40W2.

The propeller fan F2 is rotated by a signal of a sensor for detecting the temperature inside the support member 20 and sucks the air outside the cartridge 30 into the intake hole 10W2 through the air intake hole 30W2 by its suction action. Support member 20
An air flow in the drum axial direction is formed in the hollow portion 20A.

The air flow passes through the inside of the exposure optical system to directly cool each LED 12A and absorb the heat quantity thereof, and the exhaust action of the propeller fan F2 causes the exhaust hole 40W2 of the substrate 40 to outside the apparatus. Is discharged.

In order to further enhance the cooling effect by the air flow, each of the LEDs 12A is provided with a heat radiation fin.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS.

The exposure optical system 12 in each figure is shown by a cross section in the direction of the arrow in FIG.

In the example shown in FIG. 4, the support member described above is used.
Reference numeral 20 designates an axis of the hollow portion 20A, and the LED 12A of each of the exposure optical systems 12 is projected on the peripheral surface of the hollow portion 20A.
A propeller fan F3 is installed behind the intake hole 40W3 that opens.

The propeller fan F3 is rotated by a signal of a sensor for detecting the temperature inside the support member 20 and sucks air outside the substrate 40 into the hollow portion 20A through the suction hole 40W3 by its suction action. , An air flow in the axial direction of the drum is formed inside the supporting member 20, and further collides with the flange 10A to reverse the direction, and the inner surface of the photosensitive drum 10 and the supporting member
Similarly, an air flow opposite to the drum axis direction is formed in a cylindrical space between the outer surface of the substrate 20 and the outer surface of the substrate 20, and then the air is discharged to the outside of the apparatus through a plurality of exhaust holes 40W4 formed in the substrate 40.

The air flow formed in the hollow member 20A of the support member 20 directly cools the LED 12A of each exposure optical system 12, while the air flow formed in the space between the photoconductor drum 10 and the LED 12A is the amount of heat on the inner surface of the drum. At the same time, the self-ox lens 12B of each exposure optical system 12 is also cleaned.

In order to further enhance the effect of cooling and cleaning by each air flow, each LED 12A is provided with a heat radiation fin, and the intake hole 40W3 is provided with a dustproof filter f3. Is attached.

On the other hand, in the example shown in FIG. 5, the supporting member 20 has an axial center as a hollow portion 20A whose one end is closed, and the peripheral surface of the hollow portion 20A is provided with the exposure optical systems 12 described above. L
Exhaust hole 40W protruding from ED12A and further opening substrate 40
A through cylinder P through which 5 is inserted is housed inside.

The through-cylinder P is provided with a propeller fan F4 at the end portion on the substrate 40 side, and a predetermined space is formed between the outer periphery of the propellant fan F4 and the inner surface of the support member 20 to form the space through the exhaust hole.
It is connected to 40W5.

The propeller fan F4 rotates the temperature inside the support member 20 in response to a signal from a detection sensor and sucks air outside the substrate 40 into the communicating cylinder P by its suction action, and at the end of the support member 20. Support member by reversing direction
It is sent into the above-mentioned space on the inner surface to form an air flow in the axial direction of the drum.

The air flow formed on the inner surface of the support member 20 directly cools the LED 12A of each exposure optical system 12 and absorbs the heat quantity thereof, and the exhaust action of the propeller fan F4 causes the exhaust hole 40W5 to be opened in the substrate 40. Is discharged to the outside of the device.

In order to further enhance the cooling effect by the air flow, each LED 12A is provided with a heat radiation fin.

In each of the above embodiments, an apparatus using a drum-shaped image forming body has been described. However, the present invention uses a belt-shaped image forming body, and each image exposing means is housed inside. It can also be applied to an apparatus, and the same cooling effect can be obtained.

[0052]

According to the present invention, the image exposing means is prevented from overheating even when an image is formed for a long time, so that the inside of the image forming body is always kept within an appropriate temperature range. Therefore, a color image forming apparatus capable of continuously forming high-quality images without deterioration or change in resist is provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing a color image forming apparatus of the present invention.

FIG. 2 is a sectional view showing a cooling means (first) inside the photoconductor according to the first embodiment.

FIG. 3 is a sectional view showing cooling means (No. 2) inside the photoconductor according to the first embodiment.

FIG. 4 is a cross-sectional view showing a cooling means (first) inside the photoconductor according to the second embodiment.

FIG. 5 is a sectional view showing cooling means (No. 2) inside the photoconductor according to the second embodiment.

[Explanation of symbols]

 10 Photosensitive drum 10A, 10B Flange 11 Charging device 12 Exposure optical system 12A LED 12B Self-ox lens 13 Developing device 14A Transfer device 14B Static eliminator 15 Paper feed cassette 16 Timing roller 17 Fixing device 19 Cleaning device 20 Supporting member 20A Hollow part 30 Cartridge 40 board F propeller fan f filter P through cylinder

Claims (8)

[Claims] 1. An image forming body is repeatedly charged by a charging means, image exposing by an image exposing means, and developing by a developing means to form toner images on the image forming body in a superimposed manner, and then collectively transferred to a transfer material. In the color image forming apparatus, the image exposing unit is included in the image forming body and is cooled by an air flow passing through the image forming body. 2. The color image forming apparatus according to claim 1, wherein the image exposure unit is cooled by an air flow passing through the outside of the image exposure unit. 3. The color image forming apparatus according to claim 1, wherein the image exposing unit is cooled by an air flow passing through the inside of the image exposing unit. 4. The color image forming apparatus according to claim 1, wherein the image exposing unit includes a heat radiation fin. 5. A toner image is superposed on the image forming body by repeating charging of the image forming body by a charging means, image exposure by an image exposing means, and development by a developing means, and then batch transfer to a transfer material. In the color image forming apparatus, the image exposing unit is enclosed in the image forming body and is cooled by an air flow circulating in the image forming body. 6. The color image forming apparatus according to claim 5, wherein the image exposing unit is cooled by an air flow circulating inside and outside the image exposing unit. 7. The color image forming apparatus according to claim 5, wherein the image exposing unit is cooled by an air flow circulating inside the image exposing unit. 8. The color image forming apparatus according to claim 5, wherein the image exposing unit includes a fin for heat dissipation.