JPH03103871A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent an elecrifier and an image carrier from generating a scratching mark even when a press-contact type electrifier is used for the image carrier assembled in a process cartridge by providing a support mechanism of an electrifying means with a means for separating the electrifying means from the image carrier interlocked with the attaching / detaching of the process cartridge. CONSTITUTION:An electrifying roller 12 is supported on the side of a device main body 1; usually the electrifying roller 12 is pressed against a photosensitive drum 10 in the process cartridge 14; when the process cartridge 14 is removed from the device main body 1, the electrifying roller 12 is separated from the process cartridge 14 by the pressing part 34 of the process cartridge 14, the bent part 31d of a roller supporting plate 31, etc. Thus, when the process cartridge 14 is removed from the device main body 1, the electrifying roller 12 and the photosensitive body 10 do not rub against each other. Therefore, in the attaching / detaching of the cartridge 14, the occurrence of the scratching mark, which results from the rubbing of the electrifying means against the image carrier, is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus such as a laser printer or an electrophotographic copying machine, and particularly to an image forming apparatus having a type of charging means that presses against an image carrier.

(Prior art) An image forming apparatus such as a copying machine uses an image carrier (photosensitive tram),
In many cases, process equipment such as a cleaning device or developing device is housed in a cartridge container, and the process cartridge is integrally attached to and removed from the main body of the device. In some cases, when the process cartridge runs out or the consumables (for example, toner in the developing machine) are used up, the entire process cartridge is replaced to facilitate maintenance.

Further, chargers such as a primary charger and a transfer charger are arranged around the photosensitive drum to apply various charges to the photosensitive drum. Types of such chargers include non-contact type corona chargers that utilize corona discharge, and roller type charging rollers that are used in contact with the photosensitive drum.

Here, when Corona Teidenki is used as the primary charger,
Since the corona charger is used without contacting the photosensitive tram, even if this primary charger is supported on the apparatus main body side outside the process cartridge, will there be no inconvenience when the process cartridge is attached to and removed from the apparatus main body?
This corona charger generates harmful ozone during corona discharge, so an ozone filter is required inside the device itself, which increases costs and increases the size of the device.

If a charging roller is used as a primary charger for the corona charger described above, it has the advantage of almost no ozone generation, but since the charging roller is in pressure contact with the photosensitive tram, the charging roller cannot be used outside the process cartridge. If the process cartridge is supported on the apparatus main body side, the photosensitive drum and charging roller will rub against each other when the process cartridge is attached to and removed from the apparatus main body, causing scratches on the surface of the iriko tram and {1 shi electric roller, which will adversely affect the formed image. There were some inconveniences such as being short. Therefore, when a Teiden roller is used as the primary Teiden device, the charging roller needs to be incorporated into the cartridge container of the process cartridge in order to prevent unnecessary friction between the charging roller and the photosensitive tram.

(Problem to be solved by the invention) However, when a primary charger is incorporated into a process cartridge, the primary charger can be used almost permanently, whereas other process devices in the process cartridge can be used relatively permanently. Due to the short lifespan, when replacing the process cartridge, the primary charger, which still has sufficient life left, has to be replaced, resulting in waste.

In addition, if the process cartridge is used for a long time after it is manufactured, the charging roller will continue to press the photosensitive tram at the same location, resulting in pressure marks on the charging roller and the photosensitive tram, which may cause image distortion. There were some inconveniences.

The present invention has been made in view of the above-mentioned problems, and its purpose is to prevent the charger from discharging even if a pressure-contact type Vi'f electric device is used for the image bearing member incorporated in the process cartridge. An object of the present invention is to provide an image forming device that does not cause rubbing marks or pressure marks on the image bearing member or the image carrier.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a process cartridge having at least an image carrier, which is disposed in a main body of an image forming apparatus, and in which the image carrier is arranged around the image carrier. In an image forming apparatus equipped with a pressure-contact type charging means,
The 4+F charging means is supported on the side of the image forming apparatus main body outside the process cartridge, and when the process cartridge is attached to and removed from the image forming apparatus main body, the support mechanism of the charging means is connected to this {{
The present invention is characterized in that a separating mechanism is provided to separate the IF electric means from the image carrier.

(Function) Even if the charging means is supported on the side of the image forming apparatus main body outside the process cartridge, and this charging means is of a type that presses against the image bearing member inside the process cartridge, the process cartridge cannot be connected to the image forming apparatus main body. Since the charging means is separated from the image carrier through a separation mechanism when the process car 1 is attached to and detached from the image carrier, the charging means and the image carrier rub against each other, causing the charging means and the image carrier to rub against each other. No scratches are generated on the image carrier.

(Example) An example of the present invention will be described below with reference to the accompanying drawings, taking a laser printer as an example of an image forming apparatus.

First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

First, an overview of the image forming apparatus will be explained with reference to FIG.
The reference numeral 10 is a photosensitive drum having an image holding member, and around the photosensitive drum 10 there is a cleaning device 11 and a primary charger l.
2. Process equipment such as the developing device 13 is disposed, and in the device body 1 below these equipment, on the feeding side of the transfer paper P,
Paper feed tray 20, paper feed roller 21, registration roller 22
A conveyor belt 24, etc. are arranged on the paper discharge side of the transfer paper P,
A fixing device 25, a paper discharge roller 26, etc. are provided, and a transfer charger 23 is provided below the photosensitive drum 1O.

That is, the image light L is emitted from a laser scanner unit (not shown) onto the photosensitive drum 10, which is uniformly charged by the primary charger 12.
When exposed to light, an electrostatic latent image is formed on the photosensitive drum 10, and as the photosensitive drum 10 rotates, the electrostatic latent image is sent toward the developing device 13, and the developing device in the developing device 13 is transferred. The electrostatic latent image is visualized through the agent (toner) t and converted into a toner image. This toner image is then transferred onto the transfer paper P via the transfer charger 23, and after the transfer, the photosensitive drum 10 is cleaned of residual toner by the cleaning device 11 and placed on standby for the next image formation.

On the other hand, the transfer paper P in the paper feed tray 20 is taken out one by one via the paper feed roller 21 and conveyed toward the registration rollers 22. The toner image on the photosensitive drum 10 is transferred onto the transfer paper P by being conveyed between the photosensitive drum IO and the transfer charger 23 in synchronization with the image. The transfer paper P carrying the toner image is sent to the fixing device 25 via the conveyor belt 24, and when the toner image is fixed as a permanent image by the fixing device 25, it is transferred via the paper ejection roller 26. It is stacked on the tray 27.

Now, the photosensitive tram lO, the cleaning device 11. The developing device 13 is incorporated in a cartridge container 14a, and is detachably disposed integrally with the apparatus main body 1 as a process cartridge 14. When the waste toner container 11a in the cleaning device 11 becomes full of waste toner t. When the toner t in the developing device 13 is used up, or when the life of the photosensitive drum 10, the developing device 13, etc. has expired, the process cartridge 14 can be easily maintained by replacing the entire process cartridge 14. The goal is to As shown in FIG.
5 in the axial direction of the photosensitive drum 10 (X, Y in FIG.
It is designed so that it can be attached to and detached from the device body 1 in a horizontal state back and forth in the direction (direction).

Also, is the primary charger l2 a type of charging roller that is used in pressure contact with the photosensitive drum 10?
2 is supported on the device main body L side, and the process cartridge L
The photosensitive tram 1 is inserted into the process cartridge 14 through the insertion hole 14b of the cartridge container 14a of No. 4.
It is pressed to 0. When the process cartridge l4 is attached to and removed from the main body 1 of the apparatus, the primary charger l2 releases pressure on the photosensitive drum lO and separates from the photosensitive drum.
By attaching and detaching the photosensitive drum 10 and the primary charger l2 to and from the apparatus main body 1, the photosensitive drum 10 and the primary charger l2 are prevented from rubbing against each other.

Here, the support mechanism of the primary charger l2 and its operation will be explained with reference to FIG. 2 and the like. In addition, the following is the primary charger l
2 shall be called a charging roller.

As shown in FIG. 3, the support shaft 30 is attached to the wooden frame l in parallel with the axial direction of the photosensitive drum 10 of the process cartridge 14.
A roller support plate 31 is rotatably supported on the support shaft 30 . A charging roller l2 is rotatably supported on the lower side of the right end portion 31a of the roller support plate 31, which is parallel to the support shaft 30. That is, support portions 3lb, 3lb (only one is shown in FIG. 3) project downward from the front and rear ends of the right end portion 31a of the roller support plate 3l, and guide grooves 3lb-1. 3lb-1, shaft portions 12a, 12a at both ends of the charging roller l2 are pivotally supported. And the enlarged diameter portion 12b of the shaft portions 12a, 12a at both ends of the charging roller l2.
, 12b and the lower surface of the right end portion 3lb of the roller support plate 12 (only one side is shown in FIG. 3).
b, 3lb is pressed downward in the guide groove 3lb-1.31bl.

Further, the right end portion 31c of the roller support plate 3l is a bent portion 31d that is bent downward from its front end, and the lower end portion 31d-1 of the bent portion 31d is inclined downward sequentially from the front to the rear. It has a shape. Further, the upper surface side of the right end portion 31a of the roller support plate 3l is lifted up by a spring member 33 hanging down from the apparatus main body 1, and the roller support plate 3l is supported in a substantially horizontal state around the support shaft 30.

On the other hand, when the process cartridge l4 is installed in the apparatus main body l, this process cartridge 14 is inserted in a horizontal state below the roller support plate 3l positioned in the horizontal state, but the right end of the roller support plate 31 is Part 31
A roller insertion hole 14b is located in the cartridge container 14a below the charging roller 12 supported by a, so that the electricity saving roller l2 can approach the photosensitive drum 10 of the process cartridge 14. Also process cartridge l4
Cartridge container 14a in the direction of attachment and detachment to the device main body l of
A pressing portion 34 is provided on the upper front portion of the roller support plate 31 and has a shape that rises toward the front and engages with a lower end 31d-1 of a bent portion 31d provided on the left end 31c of the roller support plate 31.

When the process cartridge l4 is removed from the apparatus main body 1l, since the roller support plate 31 is positioned in a substantially horizontal state, the process cartridge l4 is inserted into the cartridge insertion hole 15 at the front of the apparatus main body l.
Therefore, even when installed in the apparatus main body 1, the roller support plate 3l and the charging roller 12 attached to the roller support plate 31 do not become an obstacle to the installation of the process cartridge l4.

When the process cartridge l4 is almost installed in the apparatus main body 1, the pressing part 34 of the cartridge container 14a engages with the lower end 31d-1 of the bent part 31d of the roller support plate 3l. rotates clockwise in FIG. 3 against the elastic force of the spring member 33, and its right end 31a is pushed downward. Therefore, charging roller l2
is inserted into the cartridge container 14a through the roller insertion hole 14b of the process cartridge 14, and is pressed against the photosensitive drum IO. In this case, charging roller 1
Even if the charging roller 12 is moved toward the photosensitive drum 10 by an excessive amount, the charging roller 12 escapes upward through the spring members 32, 12 32 and the guide holes 3lb-1.3lb-1, so that the charging roller 12 and the photosensitive drum 10 Appropriate pressure is applied. Therefore, when forming an image, the photosensitive drum 10 is properly and uniformly charged by the charging roller 12 {12
Electricity will be applied.

In addition, when removing the process cartridge l4 from the apparatus main body l, first pull the process cartridge 14 forward slightly (in this case, the friction between the iF electric roller l2 and the photosensitive tram 10 is negligible). ), the engagement between the pressing part 34 of the cartridge container 14b and the bent part 31d of the roller support plate 31 is released, and the roller support plate 3l is rotated counterclockwise in FIG. 3 by the elastic force of the spring member 33. The charging roller l2 is connected to the cartridge container 14a.
The process cartridge 1 is inserted through the roller insertion hole 14b of the
4, and the roller support plate 3l is positioned in a substantially horizontal state. Therefore, after this, process cartridge l4
can be easily taken out of the mounting body.

As is clear from the above explanation, even if the charging roller 12 is supported on the apparatus main body l side and the charging roller 12 is normally pressed against the photosensitive tram lO in the process cartridge l4, the process cartridge 14 can be moved away from the apparatus main body l. When removing the process cartridge 14, the charging roller l2 is separated from the process car 1 and the ridge l4 by the pressing part 34 of the process cartridge 14 and the bending part 31d of the roller support plate 3l. When taking out the charging roller 12 and the photosensitive drum 1
0 will not rub against each other. Also, when installing the process cartridge l4 into the apparatus main body 1, the Teiden roller l2 is spaced apart from the process cartridge l4, so it does not become an obstacle to installing the process cartridge l4 into the apparatus main body 1, and the process cartridge 1
Since the charging roller 12 is inserted into the process cartridge 14 and pressed against the photosensitive tram 10 just after the installation of the process cartridge 4 into the apparatus main body 1 is completed, the charging roller 12 and the photosensitive tram 10 do not rub against each other. .

Furthermore, since the charging roller 12 is disposed outside the process cartridge 14, even if the process cartridge 14 is not used for a long period of time, the charging roller 12 continues to press the photosensitive tram 10, and the photosensitive tram 10 and the charging roller 12
There will be no pressure marks on the surface.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In the first embodiment, the process cartridge 14 was attached to and removed from the apparatus main body 1 from the front side of the apparatus main body 1 in the axial direction of the photosensitive drum 10, that is, in the front-rear direction (x, y direction). In the embodiment, the process cartridge l
4 in the left-right direction (fourth direction) perpendicular to the axial direction of the photosensitive drum 10.
It is designed to be attached to and detached from the device main body l in the direction (R, Q direction in the figure). Even in such a case, when the process cartridge 14 is attached to and removed from the apparatus main body l, the charging roller 12 is spaced 15 degrees apart from the process cartridge l4.

That is, as shown in FIG. 4, the process cartridge 14 is supported by a portion of the upper cover 1a of the apparatus main body 1, and in order to attach or remove the process cartridge 14 to the apparatus main body 1, the upper cover must be opened as shown in FIG. Open the section 1a upward using one end as a fulcrum, and then move the process cartridge 14 in the direction shown by the arrow R.
, Q directions to attach and detach the device to and from the main body 1.

As shown in FIG. 5, the roller support plate 3l is
The left end 31c of the support shaft 30 is supported on the side, and the right end 31a of the roller support plate 3l has a support portion 3lb for supporting the charging roller l2 or its both end shaft portions 12a, 12a, as in the first embodiment. , 3lb guide groove 3lb = 1.3lb-1
It is pivoted and supported within. and roller support plate 3
1, a bending engagement part 4l protrudes to the right through a thin connection part 40, and the bending retention part 4l is connected to the connection part 40.
The bent l 6 engaging portion 4l is bent downwardly in an arc shape, and due to the spring action of the connecting portion 40, the bent l 6 engaging portion 4l can be vertically displaced. Further, a spring member 35 from the mounting main body 1 side is attached to the roller support plate 3l, and the right end portion 31a of this roller support plate 31 is in a state where it is sufficiently pressed downward by the spring member 35.

Also, the cartridge container 14 of the process cartridge l4
A guide plate 42 is attached to the front end of a, and the lower surface of the bending retaining portion 4l of the roller support plate 3l is slidably engaged with the upper surface of the guide plate 42. Notch portion 42a having the same shape as hIi curved engagement portion 4l
is formed.

When installing the process cartridge l4 into the apparatus main body l with the facing facing the The plate 3l rotates around the support shaft 30, and the charging roller l2 supported by the right end portion 31a is positioned in the installation path of the process cartridge l4 below. The iF electric roller l2 may be considered to be an obstacle to mounting the process cartridge 14, or the left end of the process cartridge l4 may be attached to the charging roller 12.
In order to push up the left end portion 42b of the guide plate l4 or the bending engagement portion 4l of the roller support plate 3l against the elastic force of the spring member 35, the roller support plate 3l It rotates counterclockwise in the figure and pushes up the charging roller l2. Therefore, the process cartridge 14
can be easily installed inside the main body l of the device. In this case, the bending engagement portion 4l of the Teiden roller l2 slides on the upper surface 42c of the guide plate 42 of the process cartridge l4, and is finally positioned on the notch 42a of the guide plate 42, so that the roller support plate The charging roller l2 on the roller 3l is inserted into the process cartridge l4 through the roller insertion hole 14b of the cartridge container 14a, and is pressed against the photosensitive drum 10 by the elastic force of the spring member 35.

Further, when removing the process cartridge l4 from the apparatus main body 1, the operation completely opposite to the above is repeated. As a result, the process cartridge 14 can be separated from the process cartridge l4 and taken out of the apparatus main body 1 without causing friction between the charging roller l2 and the photosensitive drum 10.

As described above, the same effects as in the first embodiment can be obtained in this embodiment as well.

(Effects of the Invention) As is clear from the above description, according to the present invention, even when the charging means of the type that presses against the image carrier is disposed outside the process cartridge, the process cartridge can be attached to the main body of the image forming apparatus. Since this charging means is separated from the image carrier in the process cartridge, the charging means and the image carrier rub against each other when the process cartridge is attached and detached, leaving scratch marks on them. will not occur.

Furthermore, since this charging means is disposed outside the process cartridge, no pressure marks will be produced between the charging means and the image carrier 1 9 even if the process cartridge is not used for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of the image forming apparatus according to the first embodiment, FIG. 2 is a perspective view of the image forming apparatus with a process cartridge installed, and FIG. 3 is a view of the area around the charging roller of the image forming apparatus. FIG. 4 is a side sectional view of the image forming apparatus according to the second embodiment, and FIG. 5 is a perspective view of the area around the charging roller of the image forming apparatus. l... Apparatus main body (image forming apparatus main body), 10... Photosensitive drum (image carrier), 12... Primary charger (charging means), 31... Roller support plate (support mechanism), 31d・
...Bending portion (separating mechanism), 34... Pressing portion (separating mechanism), 4l... Bending retaining portion (separating mechanism), 42... Guide plate (separating mechanism).

Claims (1)

[Claims] In an image forming apparatus in which a process cartridge having at least an image bearing member is disposed within an image forming apparatus main body, and a charging means of a type that presses the image bearing member is disposed around the image bearing member, the charging means is supported on the side of the image forming apparatus main body outside the process cartridge, and when the process cartridge is attached to and removed from the image forming apparatus main body, the charging means is separated from the image carrier in conjunction with the attachment and detachment of the process cartridge to the support mechanism of the charging means. An image forming apparatus characterized by being provided with a separating mechanism for causing