JPH11202581A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an electrophotographic device main body much smaller in size in a state that the standby space of the cover member of a process cartridge and ventilation space around the process cartridge are secured in the device main body. SOLUTION: This process cartridge 18 is constituted by integrally providing an image carrier 12, an electrifying device 13, a developing device 15 and a cleaning device 17 in one cartridge case 19. The cover member 33 opened/closed when the process cartridge is attached to/detached from the device main body is attached to the cartridge 18. Plural apertures 33a are formed on the cover member 33. When the cartridge 18 is attached to the device main body, the cover member 33 is opened and set at a standby position where it retreats to expose the image carrier (12) in an open state, and the flow of air passing through the aperture 33a is formed by a fan so as to cool the periphery of the cartridge 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus for recording an image on a recording medium such as a sheet of paper, such as a copying machine, a printer, a facsimile, and a multifunction peripheral thereof. In particular, among these, images are sequentially formed on the image carrier by repeating charging, writing, development, transfer, cleaning, and the like, and the images are sequentially transferred to a recording medium, and the transferred image is fixed, whereby the recording medium is fixed. The present invention relates to an electrophotographic apparatus for recording an image thereon.

[0002]

2. Description of the Related Art Conventionally, this type of electrophotographic apparatus includes:
For the purpose of size reduction and maintenance convenience, an image carrier and a developing device are integrally provided in one cartridge case to constitute a process cartridge, and the process cartridge is attached to the main body of the electrophotographic apparatus. Some are detachable.

In such an electrophotographic apparatus, a cover member is provided on the process cartridge, and when the process cartridge is mounted on the apparatus main body, the main body cover of the apparatus main body is closed in conjunction with the mounting operation or after mounting. Opening in conjunction with the operation, the image carrier is opened and exposed, and the cover member is retracted to a position where it does not hinder the conveyance of the recording medium, and waits.

On the other hand, when removing the process cartridge from the apparatus main body at the time of jam clearance or the like, the cover member is interlocked with the operation of opening the main body cover of the apparatus main body to remove the process cartridge, or with the operation of removing the process cartridge. The image carrier is closed and covered with the cover member to protect the image carrier so that the image carrier is not stained or damaged when the process cartridge is stored.

However, in this type of electrophotographic apparatus, for example, an image carrier and a fixing device are arranged close to each other due to a demand for miniaturization in recent years. However, when the image carrier and the fixing device are arranged close to each other, there is a problem that the heat around the image carrier condenses due to the heat emitted from the fixing device.

For this reason, a fan provided in the apparatus main body is driven to send outside air taken into the apparatus main body to around the process cartridge through a duct, and to discharge heat inside the apparatus main body to the outside. It did not affect the periphery of the carrier.

[0007]

Therefore, in the above-described conventional electrophotographic apparatus, one side of the electrophotographic apparatus is provided inside the apparatus main body.
It is necessary to secure a standby space in which the cover member opened during use does not hinder the conveyance of the recording medium, and on the other hand, it is necessary to secure a ventilation space through which air flows around the process cartridge. There has been a demand, and there has been a limit in realizing miniaturization of the apparatus main body to meet those demands.

SUMMARY OF THE INVENTION It is an object of the present invention to further reduce the size of the electrophotographic apparatus main body while securing a standby space for the cover member and a ventilation space around the process cartridge.

[0009]

According to the present invention, an electrophotographic apparatus is provided, for example, by providing at least an image carrier 12 as in an embodiment described with reference to the following drawings. A process cartridge 18 detachably provided to the electrophotographic apparatus main body 10, a fan for creating an air flow around the process cartridge 18 in the apparatus main body 10, and a process cartridge 18 provided in the process cartridge 18. When attached to the apparatus main body 10, the image carrier 12 is opened to expose the image carrier 12, and is retracted to a position where it does not hinder the conveyance of the recording medium, and waits. A cover member 33 for covering and protecting the image carrier 12, and when the cover member 33 is opened, An opening 33a for passing the flow of that air,
It is characterized by being formed on the cover member 33.

[0010] In the first aspect of the present invention,
When the process cartridge 18 is mounted on the apparatus main body 10, the cover member 33 is opened, the image carrier 12 is exposed, and the image carrier 12 is retracted to a position where the conveyance of the recording medium is not hindered and waits. At the time of use, the fan is driven to
The air taken into the inside is sent around the process cartridge 18 to create a flow of air passing through the opening 33 a of the cover member 33, and the heat around the process cartridge 18 is discharged to the outside.

According to a second aspect of the present invention, in the electrophotographic apparatus according to the first aspect, a plurality of openings 33a are formed as in an embodiment described with reference to the following drawings. And

In the invention according to claim 2,
In use, a flow of air is generated through the plurality of openings 33a of the cover member 33, and heat around the process cartridge 18 is discharged to the outside.

According to a third aspect of the present invention, in the electrophotographic apparatus according to the second aspect, for example, according to an embodiment which will be described with reference to the following drawings, according to the arrangement position of the fan in the apparatus main body 10. , The opening area of the opening 33a,
It is characterized in that it is different in the length direction of the image carrier 12.

In the invention according to claim 3,
In accordance with the position of the fan, the opening area of the opening 33a is reduced near the fan in the length direction of the image carrier 12, and is increased near the fan.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall schematic configuration of a laser copying machine which is an example of an electrophotographic apparatus according to the present invention. In the figure, reference numeral 10 denotes a copying machine main body.
The apparatus main body 10 is provided with a drum-shaped image carrier 12.

Around the image carrier 12, a charging device 13 that charges the image carrier 12 uniformly by approaching or in contact with the surroundings, and irradiates a laser beam onto the image carrier 12 to form an electrostatic latent image thereon. An optical writing device 14 for forming an image, a developing device 15 for developing an electrostatic latent image into a toner image, a transfer device 16 for transferring the toner image to a recording medium, and cleaning for removing residual toner on the image carrier 12 The apparatus 17 includes an unillustrated static elimination lamp and the like for removing residual charges on the image carrier 12.

As described above, the image carrier 12, the charging device 13, the developing device 15, and the cleaning device 17 are connected to each other in order to reduce the size and facilitate maintenance.
A process cartridge 18 as shown in FIG. 2 is formed by being housed in one cartridge case 19 and integrally provided, and the process cartridge 18 is made detachable with respect to the copying machine main body 10.

As shown in FIG. 2, the developing device 15 of the process cartridge 18 includes stirring screws 20 and 21, a developing sleeve 22, a doctor blade 23, and a toner density sensor 24. The developing device 14 is supplied with toner from a toner supply device (not shown).

Then, as the image carrier 12 rotates counterclockwise in the figure, first, a static elimination light a is irradiated with a static elimination device (not shown) to set the surface potential of the image carrier 12 to a reference potential of 0 to -100V. Average. Next, it is charged by the charging roller 13 to make the surface potential -1100V.

Subsequently, laser light b is irradiated by the optical writing device 14 so that the surface potential of only the irradiated part is 0 to -290.
V, an electrostatic latent image is formed on the image carrier 12. After that, toner is adhered by the developing sleeve 22 to which a bias potential of about -800 V is applied, and the electrostatic latent image is developed to form a toner image on the image carrier 12.

Next, with the subsequent rotation of the image carrier 12,
The recording medium is fed from the paper feeder 25 shown in FIG. The toner image on the body 12 is transferred to the recording medium.

The recording medium after the transfer of the toner image is
Separated from the image carrier 12 and sent to the fixing device 27,
Then, the transferred toner image is fixed by applying heat and pressure, and then discharged onto the discharge stack unit 28.

On the other hand, the image carrier 12 after the transfer of the toner image
Is the cleaning blade 29 of the cleaning device 17
To remove residual toner remaining on the surface. Thereafter, the charge is removed again by irradiating a charge removing light a with a charge removing device (not shown) to prepare for the next image formation.

The residual toner scraped off by the cleaning blade 29 is conveyed in the axial direction by a toner conveying coil 30 shown in FIG. 2 and put into a conveying pipe 31 shown by a two-dot chain line in FIG. Free fall and developing device 15
Recycle to use.

The developing sleeve 22 has a fixed shaft in which five-pole magnets are arranged, and is formed by covering the outer peripheral surface with a non-magnetic pipe material. When the pipe member rotates, the developer moves on the developing sleeve 22.

The developer is of a two-component type consisting of a small iron ball called a carrier and a toner.
By circulating while stirring at 0.21, the toner is charged and adheres to the carrier, carried to the surface of the image carrier 12 and adheres to the surface of the image carrier 12 by the action of electrostatic force.

Since the toner adheres to the image carrier 12 and is consumed, it is necessary to replenish the toner as appropriate. In addition, if the supply amount of the developer to the image carrier 12 is not constant, image density defects and density unevenness occur. Therefore, the doctor blade 23 regulates the inflow amount of the developer.

The cartridge case 19 of the process cartridge 18 used in the above-described laser copying machine has a window 19a for exposing a part of the image carrier 12 to be exposed, as can be seen from FIG. Then, a cover member 33 is provided on the window 19a by being attached to the cartridge case 19.

As shown in FIG. 3, the cover member 33 has an elongated plate shape, a plurality of round holes 33a of equal size are provided at equal intervals in the length direction, and a support shaft 33b is provided on one side. That is, it is curved in accordance with the curvature of the peripheral surface of the image carrier 12.

When the process cartridge 18 is mounted on the apparatus main body 10, the apparatus main body 1 is linked to the mounting operation by a known means or after the mounting.
The cover member 33 is opened in conjunction with the operation of closing the body cover (not shown), and the image carrier 12 is opened and exposed as shown in FIG. .

In use, the toner image on the image carrier 12 is transferred to the sent recording medium by the transfer device 16, and after image transfer, the toner image is separated from the image carrier 12 and fixed to the fixing device 27. Then, heat and pressure are applied between the nip between the fixing roller 35 and the pressure roller 36 of the fixing device 27 to fix the transferred toner image, and then the sheet is discharged onto the sheet discharge stack unit 28.

At this time, a fan (not shown) provided in the apparatus main body 10 is driven to send cool air taken into the apparatus main body 10 around the process cartridge 18 and pass through the opening 33a of the cover member 33 as shown in FIG. The air around the process cartridge 18 is discharged to the outside by creating a flow of air.

On the other hand, when the process cartridge 18 is taken out of the apparatus main body 10 at the time of jam clearance or the like, the main body cover (not shown) of the apparatus main body 10 is opened by a known means in order to take out the process cartridge 18.
Alternatively, the cover member 33 is closed in conjunction with the removal operation of the process cartridge 18, and the image carrier 12 is covered and protected by the cover member 33 as shown in FIG. Or get dirty,
The image carrier 12 is not damaged.

In the illustrated laser copying machine described above, the opening 33a of the cover member 33 has a round hole shape, but is not limited to the round hole shape, but may have a long hole shape, other hole shapes, a lattice shape, or a groove shape. .

The opening area of the opening 33a is changed according to the position of the fan in the apparatus main body 10.
0, and the opening area of the opening 33a is
In the length direction of the image carrier 12, it is good to make it small near the fan, and to make it large away from the fan.

For example, when a fan is provided on the back side in the apparatus main body 10, the flow rate of air passing around the process cartridge 18 increases on the back side and decreases on the front side. Therefore, the opening area of the opening 33a is increased on the back side,
When it is reduced on the front side, the flow rate of air passing around the process cartridge 18 can be made equal in the length direction of the image carrier 12.

Similarly, when the fan is provided at an intermediate position in the longitudinal direction of the image carrier 12, if the opening area at the intermediate position is reduced and the opening areas at the back and front sides are increased, the image carrier 12 Can be uniformly cooled in the longitudinal direction.

[0038]

As described above, according to the present invention, when the process cartridge is mounted on the apparatus main body, the cover member is opened to expose the image carrier, and the image carrier is retracted to a position which does not hinder the conveyance of the recording medium. Then you can wait. In addition, during use, the fan is driven to send air taken into the apparatus main body around the process cartridge, and the air around the process cartridge is created through the opening of the cover member to discharge heat around the process cartridge to the outside. The temperature rise in the body can be suppressed.

The standby space for the cover member and the ventilation space around the process cartridge are also used, so that the standby space for the cover member and the ventilation space around the process cartridge are secured in the main body of the electrophotographic apparatus. Can be further reduced in size.

According to the second aspect of the present invention,
In use, the air flows through the plurality of openings of the cover member to create air, and the heat around the process cartridge is discharged to the outside. Therefore, the strength of the cover member can be increased as compared with the case where one opening having the same opening area is provided. At the same time, ventilation can be performed in the entire area of the image carrier in the longitudinal direction.

According to the third aspect of the present invention, in addition to the above, according to the position of the fan, the opening area of the opening is made smaller near the fan in the length direction of the image carrier, and is separated from the fan. Since the size is increased in the vicinity, the flow rate of the air flowing in the length direction of the image carrier can be equalized, and the area around the process cartridge can be cooled uniformly.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of a laser copying machine as an example of an electrophotographic apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram around a process cartridge used in the laser copying machine.

FIG. 3 is a perspective view of a cover member used in the process cartridge.

FIG. 4 is a schematic configuration diagram of a process cartridge in a state where a cover member is closed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Apparatus main body 12 Image carrier 18 Process cartridge 19 Cartridge case 19a Window 33 Cover member 33a Opening 33b Support shaft

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Ohkaji 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kenzo Tatsumi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Hiroshi Mizusawa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Hideki Zennami 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Mayumi Ohori 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (3)

[Claims] 1. A process cartridge provided with at least an image carrier and detachably attached to an electrophotographic apparatus main body, a fan for creating an air flow around the process cartridge in the apparatus main body, and When the process cartridge is mounted on the main assembly of the apparatus, the process cartridge is opened to expose the image carrier, retracted to a position where the conveyance of the recording medium is not hindered, and waited, then removed from the main body of the apparatus. A cover member that is closed to cover the image carrier and protects the image carrier. When the cover member is opened, an opening through which air flows by the fan is formed in the cover member. apparatus. 2. The device according to claim 1, wherein said plurality of openings are formed.
An electrophotographic apparatus according to claim 1. 3. The electrophotographic apparatus according to claim 2, wherein an opening area of the opening is made different in a length direction of the image carrier in accordance with an arrangement position of the fan in the apparatus main body.