JPH03123380A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the reliability of the device by having a surface of an image carrier and a contact electrifying member not come into contact to interfere each other, in the attaching / detaching operation process of the processing cartridge to the device main body, and after completion of loading, having the contact electrifying member and the image carrier specifically abutted to each other. CONSTITUTION:A cartridge C is loaded without having an outer surface of a cover 4 or the photosensitive body 1 surface parts, which are exposed from first and second openings 4a and 4b, not come into contact and be interfered by the electrifying roll 5 or the transfer roll 8 of the device main body side, and traveled and guided to the direction of extraction. When, loaded, if the photosensitive body 1 and the rolls 5 and 8 come into contact with each other before the tip of the cartridge C is received by a receiving member 105, when further pushed in, the contact pressure is increased, and the photosensitive body 1 and the rolls 5 and 8 are finally abutted to each other at a specified pressuring force. Thus, trouble such as failure to electrify or damaging of the photosensitive body surface, etc., which are caused by contact and interference between rolls 5 and 8 on the main body side can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to image forming apparatuses such as electrophotographic copying machines, laser beam printers, electrostatic recording apparatuses, and the like.

More specifically, the present invention relates to an image forming apparatus that performs image formation by an image forming process means that includes a step of charging the surface of an image bearing member such as an electrophotographic photoreceptor or an electrostatic recording dielectric material.

(Prior Art) In this type of image forming apparatus, a corona discharge device has conventionally been widely used as a means for charging the surface of an image carrier such as a photoreceptor.

A corona discharge device is effective as a means for uniform charging treatment. However, it has problems such as requiring a high-voltage power source (5 to 8 KV DC), generating a relatively large amount of ozone when corona occurs, and being inefficient in terms of electric power.

Therefore, instead of a corona discharge device, contact charging is used as a means of charging the surface of a charged object such as a photoreceptor, in which a voltage is applied or a charging member for frictional charging is brought into contact with the surface of the charged object to perform charging (including charge removal processing). The means are attracting attention.

In particular, charging members to which a bias voltage is applied (roller type, belt type, stationary web type, blade type, rod type, block type,
A contact charging method (or direct charging method) or similar method in which charge is directly transferred (injected) to the surface of the charged object to charge it to a predetermined potential by bringing a pad type, brush type, etc. into contact with the surface of the charged object. The device is capable of reducing the applied voltage required to obtain a desired charging potential on the surface of the charged object, and the amount of ozone generated during the charging process is extremely small, eliminating the need for an ozone filter. Therefore, the configuration of the exhaust system, etc. of the device should be simplified.

It has the advantage of being simple in structure, and many proposals for practical research and development have been made (Japanese Patent Laid-Open No. 1983-1999).
178287-58-104351 @5B-4058
No. 6-58-139158-58-150975, etc.).

The present applicant also applied a direct current voltage to the charging member and an oscillating voltage (voltage whose voltage value changes periodically over time) that is more than twice the charging start voltage of the surface of the charged object for the purpose of uniform charging processing without uneven charging. ), and making the charging member have a multi-layer structure in order to eliminate abnormal discharge and dielectric breakdown from the charging member to the surface of the charged object (Patent Application No. 81). -298419 ・f12-23
No. 0334, etc.).

On the other hand, one of the configurations of an image forming apparatus is a removable process cartridge type. This means that at least an image bearing member such as a photoconductor, generally an image bearing member, some image forming process means such as a charging processing means for the @ carrying member, a developing processing means, a cleaning means for the image carrying member, etc. The cartridge cover (cartridge frame, housing) is assembled in a predetermined arrangement relationship with each other, and these components can be easily and easily attached to and detached from the main body of the image forming apparatus. .

In principle, this removable process cartridge is used to form images for a specified number of sheets (for example, 3,000 to 5,000 sheets) and then is replaced with a new process cartridge, assuming that its useful life has come to an end. Maintenance is free, the operability and handling of the image forming apparatus is improved, and multicolor images can be formed by replacing several process cartridges that contain different colors of developer. Since it has advantages, it has been put to practical use as a configuration of an image forming apparatus such as a personal type small and simple model.

In such an image forming apparatus of the process cartridge removable type, as a means for charging an image bearing member such as a photoreceptor included in the process cartridge, a voltage is applied as described above or a charging member for frictional charging (hereinafter referred to as contact charging) is used. If a means for carrying out charging by bringing a member (referred to as a member) into contact with an image carrier is adopted, a simpler type of image forming apparatus can be constructed than when a corona discharge device is used.

In this case, since the contact charging member itself is a long-life member that is durable and can be used repeatedly over a long period of time, this member is not provided on the process cartridge side, which is a disposable side, but in the image forming device, which is a durable side. Providing the equipment on the main body side can simplify the structure of the process cartridge and is advantageous in terms of cost.

(Problems to be Solved by the Invention) When the contact charging member is provided in the main body of the image forming apparatus as described above, when the process cartridge is installed in the main body of the image forming apparatus, It goes without saying that the apparatus is configured so that the contact charging member and the image bearing member on the side of the installed process cartridge come into contact with each other in a predetermined manner. During the attachment/detachment process, it is necessary to prevent contact interference between the contact charging member and the process cartridge side (the image carrier surface or the outer surface of the cartridge cover).

Such contact interference can occur, for example, due to unnatural contact or abrasion between the contact charging member and the image carrier, such as sharp parts of the contact charging member (
For example, if the contact charging member is a blade type, the image bearing member may be damaged by the tip (edge), or conversely, the contact charging member may be unnaturally bent or dirt may adhere to it, causing charging problems. It is from.

Therefore, it is conceivable to provide an avoidance mechanism for the contact charging member to move and hold the member to a retracted position where there is no contact interference with the cartridge side during the process of attaching and detaching the process cartridge to the main body of the image forming apparatus. When the cartridge is installed, a retraction release mechanism is also required to move the contact charging member from the retracted position to the image carrier surface and bring it into contact with a predetermined position, which is undesirable because it complicates the configuration of the image forming apparatus main body.

The present invention has been devised to prevent contact interference between the contact charging member and the process cartridge side during the process of attaching and detaching the process cartridge to and from the main body of the image forming apparatus with a simpler means configuration.

(Means for Solving the Problems) The present invention is an image forming apparatus that executes image formation by an image forming process means including a step of charging the surface of an image bearing member, and in which at least an image of the image forming process means is The carrier is configured as a process cartridge that can be attached to and detached from the main body of the image forming apparatus.

The means for charging the surface of the image carrier on the process cartridge side is disposed on the image forming apparatus main body side, and when the process cartridge is installed in a predetermined position in the image forming apparatus main body, the image carrier on the process cartridge side is charged. It is a contact charging member that is in contact with the surface of the carrier in a predetermined manner, and during the process of attaching and removing the process cartridge to and from the image forming apparatus main body, the process cartridge or the surface of the image carrier on the process cartridge side comes into contact with the image forming apparatus main body. The process cartridge is attached to and removed from the image forming apparatus main body so that the contact charging member and the image carrier are in a predetermined contact state only when the process cartridge is completely attached to the image forming apparatus main body without contact interference with the charging member. The image forming apparatus is characterized in that it is configured in the shape of a path or a process cartridge.

Further, the present invention relates to the image forming apparatus as described above, in which the contact charging member is of a form in which a certain surface portion is always in contact with the image carrier, and the process cartridge attachment/detachment path of the image forming apparatus main body is connected to the contact charging member. The process cartridge attachment/detachment path of the main body of the image forming apparatus must be located on the side that contacts the image carrier, and the process cartridge attachment/detachment path in the main body of the image forming apparatus is determined by the contact pressure between the contact charging member and the image carrier that come into contact with each other when the process cartridge is attached. The process cartridge is installed in a direction such that the contact pressure increases and the contact pressure decreases with respect to the process cartridge removal direction, and the process cartridge is installed in the image forming apparatus main body in a predetermined state. The image forming apparatus is characterized in that it has an opening at a position corresponding to the contact charging member on the side that allows the contact charging member to come into contact with the image carrier on the process cartridge side.

(Function) By configuring the process cartridge installation/removal path or the process cartridge shape of the image forming apparatus main body as described above, a contact charging member avoidance mechanism evacuation release mechanism that complicates the configuration of the image forming apparatus main body side is provided. With a simple means configuration, contact interference between the contact charging member on the image forming apparatus main body side and the process cartridge side can be prevented during the process of attaching and detaching the process cartridge to the image forming apparatus main body (attachment and detachment movement process), and the process cartridge The contact charging member and the image carrier on the process cartridge side can be brought into contact with each other in a predetermined state only when the attachment to the main body of the image forming apparatus is completed.

Therefore, it is possible to construct a simple, low-cost process cartridge removable/contact charging type image forming apparatus that is durable (long service life) and reliable.

(Embodiments) Embodiment 1 (FIGS. 1 and 2) The image forming apparatus of this embodiment is a transfer type electrophotographic copying apparatus with a movable document table. FIG. 1 is a schematic diagram of the apparatus when a process cartridge is installed in a predetermined position in the main body of the apparatus and a copy is being executed, and FIG. 2 is a diagram showing the same during the process of attaching and detaching the process cartridge.

In FIG. 1, 100 is an exterior case of the copying apparatus main body (image forming apparatus main body), and 12 is a movable document table (transparent plate made of glass-resin, etc.) disposed on the top side of the exterior case. It is driven to reciprocate in the left and right direction. The original 0 to be copied is placed on the original table 12 with the image side to be copied facing downward in accordance with a predetermined placement standard, and the original pressing plate 12a is placed over the original 0 to be set.

The movement of the document table 12 is started based on the copy start signal, and during the movement process, the downward image surface of the set document O on the document table 12 is moved from one end side to the other end by the illumination lamp 15 at the illumination slit opening 101. The illumination is sequentially scanned toward the side, and the light reflected from the document surface of the illumination light is reflected by the imaging element 15a.
An image is formed and exposed on one surface of a rotating drum type photoreceptor as an image carrier. The photoreceptor l is driven to rotate clockwise in the direction of arrow a at a predetermined circumferential speed (process cartridge) in response to a copy start signal, and is charged by a contact charging member 5 on the upstream side of the exposure section in the rotational direction of the photoreceptor. undergoes charging treatment.

The contact charging member 5 of this example is a roller type member (hereinafter referred to as a charging roller) to which a bias voltage is applied.

The charging roller 5 of this example is composed of a metal shaft 5a and a medium resistance resin layer 5b of about 100 cm coated around the outer periphery in the shape of a roller. Both ends of the metal shaft 5a are supported by conductive bearings 6, respectively. Although the bearing 6 is not shown in the figure, it can slide freely to some extent along the guide in the direction toward the photoreceptor 1 and in the opposite direction. Reference numeral 7 designates a conductive pressure spring that constantly urges the bearing 6 to move in the direction toward the photoreceptor 1, and one end of the spring 7 is connected to a stationary member 102 on the copying apparatus main body side.
The other ends are connected to bearings 6, respectively.

The charging roller 5 is pressed against the surface of the photoreceptor 1 at a predetermined level by the pressing force of the pressure spring 7, and rotates counterclockwise as shown by the arrow as the photoreceptor 1 is rotated.

5C is a bias application power source for the charging roller 5;
In this example, a predetermined superimposed voltage of DC voltage and oscillating voltage is applied from this power supply to the charging roller j via the conductive pressure spring 7 → conductive bearing C → gold metal shaft, and the rotating photoreceptor l
The peripheral surface of is charged to a predetermined potential.

The above-described image exposure is performed on the charged surface of the rotating photoreceptor 1, thereby forming an electrostatic latent image corresponding to the exposed image on the photoreceptor surface.

The formed latent image is sequentially developed as a toner image by the developing device 2.

On the other hand, the transfer material 13 introduced into the apparatus from the transfer material inlet 103 is fed to the transfer section between the photoreceptor l and the transfer roller 8 at an appropriate timing by the registration roller pair 9, and the transfer material 13 is The toner images on the first surface of the photoreceptor are sequentially transferred.

The transfer material 13 on which the toner image has been transferred is separated from the surface of the photoreceptor 1 and sent to a fixing device 11 by a conveyor belt 10, where the image is fixed, and is discharged from the apparatus as an image-formed product.

After the image has been transferred, the surface of the photoreceptor 1 is cleaned by a cleaning device 3 to remove adhered contaminants such as residual toner, and is repeatedly used for image formation.

C is a general code for a process cartridge that is attached to and detached from the main body of the copying apparatus. In the case of this example device, three process devices, the photoreceptor 1, the developing device 2, and the cleaning device 3, are assembled in a common cartridge cover 4 in a predetermined arrangement relationship with each other, and can be freely attached to and removed from the copying IT main body. This is a process cartridge C.

4a and 4b are first and second openings provided on the top and bottom sides of the process cartridge C, respectively, and the top and bottom portions of the photoreceptor 1 inside the cartridge are exposed through these openings, respectively. exposed to the outside. When the process cartridge C is installed in the main body of the copying machine in a predetermined manner, the first opening 4a is positioned corresponding to the charging roller 5 as a contact charging member on the main body of the copying machine and the imaging element 15a. contacts the upper surface of the photoreceptor l in a predetermined manner, and the imaging element 1
5a face each other in a predetermined manner. Further, the second opening 4b is positioned corresponding to the transfer roller 8, so that the transfer roller 8 contacts the lower surface of the photoreceptor 1 in a predetermined manner.

Next, the configuration and procedure for attaching and detaching the process cartridge C to the apparatus main body in this example apparatus will be explained.

Reference numeral 104 denotes a cartridge attachment/detachment port of the copying apparatus main body, which is provided in the upper plate surface 7 portion on the right side of the illumination I slit opening 101 of the upper plate of the outer case 100 of the copying apparatus main body.

This cartridge attachment/detachment opening 104 can be exposed by pushing the document table 12 to the left as shown in the second figure.

To install the process cartridge C, insert the process cartridge into the installation/removal port 104 with the side where the cleaning device 3 is placed first, and then insert the cartridge into the cartridge housing inside the copying machine main body so that the tip end of the cartridge is inserted into the receptacle on the copying machine main body side. The member LO5 is fitted into the receiver by sufficiently pushing and moving along an unillustrated guide until it is stopped. To remove the installed cartridge C, contrary to the above, grasp the rear end side of the installed cartridge (the side where the developing device 2 is installed) or grasp the handle provided on that side and pull out the cartridge. It is done by

In this case, during the process of attaching and detaching the process cartridge C to the main body of the copying machine (the process of attaching and detaching the cartridge), the cartridge C is exposed from the outer surface of the cover 4 and the i-th and second openings 4a and 4b. The first surface of the photoreceptor is guided to move in the loading direction or unloading direction within the device main body without contacting or interfering with the charging roller 5 or transfer roller 8 on the device main body side, and the tip of the cartridge C is pushed and moved for mounting. The photoreceptor 1 and the charging roller 5 and the transfer roller 8 come into contact with each other a little before the receiver is fully inserted into the member 105 and the receiver is stopped, and the contact pressure increases with the subsequent pushing movement of the cartridge. Then, when the cartridge C is finally stopped by the receiving member 105, the cartridge attachment/detachment port 104 is opened so that the photoreceptor 1 and the charging roller 511 and the transfer roller 8 are in contact with each other with a predetermined pressing force. The cartridge holder constitutes a cartridge attachment/detachment path (cartridge attachment/detachment movement guide) and a cartridge shape between the member 105 and the cartridge holder.

Therefore, during the installation and removal process of the process cartridge C, charging defects and photoconductor surface caused by contact interference between the outside of the cover 4 on the cartridge side and the photoconductor surface and the charging roller 5 and transfer roller 8 on the copying machine main body side can occur. Trouble such as damage can be prevented by a simple means configuration.

First and second openings 4a* of process cartridge C
4b may be provided with an opening/closing shutter member that closes the opening and protects the surface of the photoreceptor and the inside of the cartridge when the process cartridge is taken out. The shutter member can be configured to automatically open when the cartridge C is attached to the main body of the copying machine, and automatically close when the cartridge C is removed from the main body of the copying machine, or it can be configured to open and close manually. It can also be used as

In this embodiment, the process cartridge C includes three process devices: a photoconductor 1, a developing device 2, and a cleaning device 3; however, other configurations may be used. For example, a cartridge C includes a photoconductor 1 and a cleaning device 3. and developer unit 2-2
It can be of any desired shape, such as a body configuration.

In addition, when the process cartridge C is installed in the apparatus main body, it is mechanically and electrically coupled with the apparatus main body to enable power transmission, power supply, control signal exchange, etc. from the apparatus main body. .

Embodiment 2 (Fig. 3) In the copying apparatus of this embodiment, the outer sieve of the apparatus main body is attached to the lower frame part 100A.
The lower frame part 100B is closed around the hinge shaft part 16 and can be opened and closed freely by the upper frame part 100B, which can be opened and opened freely. Conveyor belt 1O11 fixing device 11 etc. are arranged,
The upper frame portion 100B includes a movable document table 2, an illumination lamp 15, and
An imaging element 15a, a charging roller 5, a cartridge fitting holding member 106 for storing a process cartridge, and the like are provided.

To attach the process cartridge C to the apparatus main body, as shown in the figure, raise and open the upper frame part 100B from the lower frame part 100A to open the inside of the apparatus main body. The distal end side of the cartridge is held first, and the lower surface of the cartridge on the distal end side is received by the upper surface 106a of the bottom plate of the holding member 106, and the upper surface of the bottom plate is used as a guide to push and move the cartridge straight in the direction of arrow A. Part 10
When the cartridge C is inserted into the cartridge 6 and pushed sufficiently until the cartridge tip abuts against the member 106 and the receiver is stopped, the cartridge C's tip fits into the member 106. After that, even if you release your hand from the cartridge C, the cartridge C remains at the member 10.
6 and is stably attached and held.

In this case, the upper surface of the distal end side of the cartridge cover 4 does not contact and interfere with the charging roller 5 during the mounting movement process of the cartridge C, and the charging roller 5 and the photosensitive pair 1 do not come into contact with the charging roller 5 when the mounting of the cartridge C on the member 106 is completed. They come into contact with a predetermined pressing force.

Next, the upper frame portion 100B is closed against the lower frame portion 100A, and as a result of this closing, the lower surface of the photoreceptor l and the transfer roller 8 come into contact with a predetermined pressing force, and the main body of the apparatus becomes ready for copying. Become.

Removal of cartridge C is performed in the reverse order of cartridge installation.

The present invention has a configuration in which the positional relationship between the support position of the contact charging member and the guide of the process cartridge within the image forming apparatus remains unchanged; This can be applied by configuring the photoconductor of the process cartridge and the charging roller to be positioned.

Embodiment 3 (FIG. 4) Similarly to the above embodiment 2 (FIG. 3), the copying apparatus of this embodiment opens and closes the apparatus main body by rotating the upper frame portion 100B relative to the lower frame portion 100A. However, the cartridge storage part is provided on the lower frame part 100A side, and the cartridge C is installed by moving the upper frame part 100B to the lower frame part 100 as shown in the figure.
Raise it from A and open it to open the inside of the device body, and then open the lower frame part 100.
The cartridge C is stored in the cartridge housing section A by fitting the leading end of the cartridge into the receiver 105 and stopping the receiver, and then closing the upper frame part 100B against the lower frame part 100A.

Further, the contact charging member 5 for the photoconductor 1 is connected to the upper frame portion 100B.
In this example, the charging blade is made of an elastic material and has a surface resistance of 10 to 100 cm. A predetermined bias voltage is applied to this charging blade 5 from a power source 5C as in the case of the charging roller 5 described above. Then, the process cartridge C is attached to the lower frame part 100A, and the process cartridge C is attached to the upper frame part 100B.
At the time when the charging blade 5 is closed, the leading edge of the charging blade 5 comes into contact with the upper surface of the photoreceptor 1 with a predetermined pressing force, and the main body of the apparatus becomes ready for copying.

Removal of cartridge C is performed in the reverse order of the above-mentioned cartridge mounting procedure.

In addition, in the devices of Examples 2 and 3, the closed state of the upper frame part 100B with respect to the lower frame part 100A is stably maintained by a locking means (not shown), and by releasing the lock, it is possible to raise and open the upper frame part 100B. Become.

Further, the contact charging member 5 is not limited to the roller type or blade type in the embodiment, but may also be a rod type, block type, Φ pad type, brush type, web type, belt type, etc. It can also be a contact member.

(Effects of the Invention) As described above, according to the present invention, contact interference between the contact charging member on the apparatus main body side and the process cartridge side during the process of attaching and detaching the process cartridge to the image forming apparatus is prevented with a simple means configuration. This makes it possible to construct a durable, reliable, simple, low-cost process cartridge removable/contact charging type image forming apparatus.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the apparatus according to the first embodiment when a process cartridge is installed. FIG. 2 is the same diagram as above during the process of attaching and detaching the process cartridge. FIG. 3 is a schematic configuration diagram of the second embodiment of the apparatus during the process of attaching and detaching the process cartridge. FIG. 4 is the same diagram as above of the device of the third embodiment. 100 is an exterior casing of the main body of the apparatus, 100A-100B are upper and lower frame parts, and C is a process cartridge. 1 is a rotating drum type electrophotographic photosensitive member as an image carrier; 5 is a charging roller or charging blade as a contact charging member;

Claims (4)

[Claims] (1) An image forming apparatus that executes image formation by an image forming process means that includes a step of charging the surface of an image bearing member, and at least the image bearing member of the image forming process means is detachable from the main body of the image forming apparatus. The process cartridge is configured as a flexible process cartridge, and means for charging the surface of the image bearing member on the process cartridge side is provided on the image forming apparatus main body side, and the process cartridge is installed in a predetermined position in the image forming apparatus main body. It is a contact charging member that is in contact with the surface of the image carrier on the process cartridge side in a predetermined state, and during the process of attaching and detaching the process cartridge to the main body of the image forming apparatus, the process cartridge and the image carrier on the process cartridge side are There is no contact interference between the surface and the contact charging member on the side of the image forming apparatus main body, and the contact charging member and the image carrier come into contact with each other in a predetermined state only when the process cartridge has been completely installed in the image forming apparatus main body. An image forming apparatus characterized in that a process cartridge attachment/detachment path or process cartridge shape of an image forming apparatus main body is configured as follows. (2) The contact charging member is of a type in which a certain surface portion is always in contact with the image carrier, and the process cartridge attachment/detachment path of the image forming apparatus main body is on the image carrier contacting surface side of the contact charging member. The image forming apparatus according to claim 1, characterized in that: (3) In the process cartridge attachment/detachment path of the image forming apparatus main body, the contact pressure between the contact charging member and the image carrier that are in contact with each other when the process cartridge is installed increases in the process cartridge attachment direction, and 3. The image forming apparatus according to claim 2, wherein: is provided in a direction such that the corresponding contact pressure decreases. (4) When the process cartridge is installed in the main body of the image forming apparatus in a predetermined manner, the contact charging member and the image on the process cartridge side are placed at a position corresponding to the contact charging member on the main body of the image forming apparatus. 4. The image forming apparatus according to claim 1, further comprising an opening that allows contact with the carrier.