JPH08202241A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device which ensures the protection of a photoreceptor in the removal of jam by supporting a carry guide member, used for the guide of transfer paper after transfer, so that whose position is freely changed to open a recording-medium carry path in the lower part of a process cartridge, and allowing the opening of the process cartridge, which a photoreceptor faces, to be opened/closed by means of an image-carrier protection cover while linked with the movement of the carry guide member. CONSTITUTION: A transfer roller 11 is provided on the carry guide member 15 which is swung around a pivot shaft 22 to open the recording-medium carry path. When the carry guide member 15 turns round the pivot shaft 22 together with a transfer guide body 16 in the direction where a transfer roller 11 is separated from the photoreceptor 1, the image-carrier protection cover 31 for covering the lower part of the photoreceptor 1 is so supported by the shaft 1a of the photoreceptor 1 as to pivot on it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has at least an image carrier and a cartridge case in which the carrier is assembled.
The image forming apparatus includes a process cartridge detachably supported by the main body, a transfer device that transfers the toner image formed on the image carrier to a recording medium, and a conveyance guide member that guides the recording medium. The present invention relates to an image forming apparatus in which an opening is formed in the cartridge case so that the image carrier can face the transfer device.

[0002]

2. Description of the Related Art A process cartridge is constructed by incorporating an image carrier alone or together with another image forming process device into a cartridge case, and this process cartridge is detachably supported with respect to the main body of the image forming apparatus. Image forming apparatuses such as copying machines, printers, and facsimiles have been conventionally known. In this type of process cartridge, for example, an opening is provided in a part of the cartridge case, and a part of an image carrier made of, for example, a drum-shaped photosensitive member faces the opening, and the transfer device transfers an image through the opening. It is installed so as to face the carrier.

When the transfer device is a transfer charger, the transfer charger is installed outside the process cartridge so as to face the image carrier of the process cartridge through the opening. In the case of a transfer roller, when the toner image is transferred, the transfer roller is installed such that a part thereof enters the cartridge case through the opening and contacts the image carrier via the recording medium.

By the way, in this type of image forming apparatus, a recording medium such as a transfer paper may be jammed at the transfer portion. In order to facilitate removal of the recording medium having the jam, Displaceably supports the transfer device,
When a jam occurs, the transfer device is retracted in the direction away from the image carrier of the process cartridge, and the transfer device and the image carrier are largely opened. That is,
The recording medium conveyance path between the process cartridge and the transfer device is open.

In the image forming apparatus adopting such a configuration, the recording medium conveying path between the process cartridge and the transfer device is opened to remove the recording medium in which a jam has occurred or to perform a predetermined maintenance work. In this case, a hand, a tool or the like easily comes into contact with the image carrier through the opening of the process cartridge. When a hand or the like comes into contact with the image bearing member, the surface of the image bearing member is scratched, or the oil on the fingers adheres to the surface of the image bearing member, which causes deterioration of image quality. The life of the carrier may be shortened in some cases. Furthermore, when the process cartridge is taken out of the main body of the image forming apparatus by opening the above-mentioned transport path and placing it on the mounting portion, some protrusion on the mounting portion
The image carrier may face the opening of the cartridge case, and even in such a case, the surface of the image carrier may be damaged.

Therefore, a technique in which the opening of the process cartridge is opened and closed by a predetermined cover member has been conventionally adopted, but before the jam processing is performed,
If the user forgets to close the opening, the original protection function of the image carrier by the cover member will not be achieved.
In addition, opening and closing the cover member one by one at the time of jam handling, maintenance work, replacement of the process cartridge, etc. is very troublesome in terms of work.

As a technique related to this type of technique, a technique disclosed in Japanese Patent Laid-Open No. 5-80600 has already been proposed. Another technique has been already proposed by Japanese Patent Laid-Open No. 6-3977, in which a cover member protects a transfer roller provided so as to be in contact with an image carrier.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conveyance guide member for guiding a recording medium after toner image transfer during jam processing, maintenance work,
When the process cartridge is replaced, the recording medium conveyance path between the process cartridge and the transfer device is configured to be freely displaceable so that the image carrying of the process cartridge is performed in conjunction with the movement of the conveyance guide member. An object of the present invention is to provide an image forming apparatus in which an opening facing a body is opened and closed by a protective cover for an image carrier so that protection of the image carrier at the time of jam processing can be guaranteed without fail.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is directed to an image forming apparatus of the type described at the beginning, in which a transfer guide member and a transfer device are opposed to an image carrier. The transport guide member set position positioned at a predetermined position and the transport guide member release position where the image carrier and the transfer device are separated from each other and opened between them are movably supported and transported. In association with the displacement operation of the guide member, the opening of the cartridge case is opened when the transport guide member is in the set position, and the opening of the cartridge case is closed when the transport guide member is in the release position. We propose a configuration in which an image carrier protective cover that displaces to the right is provided as a component of the process cartridge.

At this time, the transfer device is configured as a transfer roller placed at a position in contact with the image carrier via the recording medium at the time of transferring the toner image, and this transfer roller leaves the part on the image carrier side. Of the transfer roller on the side of the image carrier is provided by a transfer roller protection cover that is interlocked with the displacement operation of the image carrier protection cover, and is exposed to the outside when the transport guide member is in the release position. When the transfer guide member is closed so as not to be exposed and the transfer guide member is at the set position, it is effective that the transfer roller protective cover is opened so as to be exposed to the outside by the retracting operation from the closed position.

Further, it is effective that the transfer roller protection cover also serves as a conveyance guide function for the recording medium.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a partial cross-sectional front view showing a transfer guide swinging component provided in an image forming apparatus according to an embodiment of the present invention together with a drum-shaped photosensitive member. In describing such a configuration unit, the outline of the configuration and the like of an image forming apparatus including the configuration unit will be clarified below.

In FIG. 4, reference numeral 1 denotes a drum-shaped photosensitive member which is an example of an image bearing member, and the photosensitive member 1 is rotationally driven in the clockwise direction in the drawing by a driving means (not shown). There is. During this rotation, first, the surface of the photoconductor 1 is set to a reference potential of, for example, about 0 to −150 V by light irradiation by the static elimination lamp 2 which is an example of the static elimination device. Then, the surface of the photoconductor 1 is uniformly charged by the function of the charging device including the charging roller 3. The surface potential of the photoconductor 1 at this time is, for example, −11.
It is around 00V.

After the charging, in the exposure section 4, the laser beam 5 is used to perform writing scanning on the photoconductor 1 in the axial direction, whereby a predetermined electrostatic latent image is formed on the photoconductor 1. It is formed. The surface potential of the photoconductor portion (image portion) irradiated with the image of the laser light is 0 to -290V, and the surface potential of the background portion (non-image portion) on the photoconductor 1 not irradiated with the laser light is about -1100V. There is. A developing device 6 is disposed opposite to the photoconductor 1, and a toner (not shown) is carried and carried on the developing roller 7 of the developing device 6. At this time, a bias voltage of about −800 V is applied to the developing roller 7, and the negatively charged toner conveyed on the developing roller 7 forms an electrostatic latent image (image portion) on the photoconductor 1. By electrostatically transferring, the electrostatic latent image is visualized as a toner image. The developing roller 7 constitutes an example of a developer transport member.

A transfer device is provided below the photoconductor 1. In this example, the transfer device is the transfer roller 11, but instead of this, a transfer charger that performs corona discharge may be used as the transfer device. From the registration roller pair 8, the front end portion of the transfer paper 9, which is an example of a recording medium, is in good contact with the front end portion of the toner image on the photosensitive member 1 at the transfer portion 12 between the photosensitive member 1 and the transfer roller 11. As described above, the transfer paper 9 is fed toward the transfer portion 12 at a timing.

The transfer roller 11 rotates in the direction of the arrow in the figure while contacting the photoconductor 1 via the transfer paper 9, and while the transfer paper 9 passes between the photoconductor 1 and the transfer roller 11, the photoconductor 1 The toner image formed on 1 is transferred to the transfer paper 9. As described above, in this example, the transfer device is configured as the transfer roller 11 which is placed at a position in contact with the photoconductor 1 via the transfer paper 9 when the toner image is transferred. After the transfer roller 11 transfers the toner image, the transfer paper 9 is separated from the surface of the photoconductor 1 by a separating unit (not shown), and after the separation, the transfer paper 9 is sent toward the fixing device 17, and the fixing device 17 is provided. While passing through 17, the transfer toner image on the transfer paper is fixed by heat and pressure. Then, after that, the copy paper is appropriately ejected outside the image forming apparatus. When the transfer paper 9 is fed toward the fixing device 17 after the transfer, the transfer paper 9 is arranged on the downstream side of the transfer unit 12 in the transfer direction of the transfer paper, and the transfer guide member 15 is provided. Guided by.
The configuration of the transport guide member 15 will be specifically described later together with the transfer guide body 16.

On the other hand, after the transfer of the toner image, the toner that has not contributed to the transfer remains adhered on the surface of the photoconductor 1, so that the adhered toner is the cleaning device 1.
It is scraped off by the cleaning blade 14 of No. 3. At this stage, the predetermined copy cycle is completed. The cleaning blade 14 constitutes an example of a cleaning member that removes residual toner on the photoconductor.

Here, in the image forming apparatus of this embodiment, the photoconductor 1, the developing device 6, and the cleaning device 13 are provided.
Are integrally configured as the process cartridge 10 assembled in the cartridge case 18, and the process cartridge 10 is detachably supported on the image forming apparatus main body. It is also possible to construct the process cartridge by assembling only the photoconductor 1 into the cartridge case 18. In short, the process cartridge has at least an image carrier and a cartridge case to which the carrier is assembled.

As described above, the illustrated image forming apparatus is
The process cartridge 10 described above, the transfer roller 11 that transfers the toner image formed on the photoconductor 1 to the transfer paper 9,
After the transfer of the toner image, the transfer paper 9 is fixed to the fixing device 17
An outer frame forming the main body of the process cartridge 10, that is, the cartridge case 1.
8 is open at a position facing the transfer portion 12. An opening 19 is formed in the cartridge case 18 so that the photoconductor 1 can face the transfer roller 11. When the toner image is transferred, the upper portion of the transfer roller 11 enters the cartridge case 18 through the opening 19 and the transfer paper 9 is interposed therebetween. And contacts the photoconductor 1.

Returning to FIG. 1, the transport guide member 15 is constructed with the transfer guide body 16 as shown in FIG.
The transport guide member 15 is arranged inside the transfer guide body 16, and the side plates at the front and rear of the guide member 15, that is, the both side plates located apart from each other in the direction perpendicular to the paper surface of FIG. It is arranged to be covered by. The transport guide member 15, together with the transfer guide body 16, is pivotally attached to a machine side plate 21 (FIG. 1) on the back side in the drawing and a machine side plate (not shown) on the front side opposite to the machine side plate 21 so as to be swingable by a pivot shaft 22. ing.

The transfer guide member 15 includes a transfer roller 11
Is rotatably mounted via a bearing (not shown), and the transfer roller 11 has a portion on the side of the photoconductor 1, in this example, a roller portion that leaves the upper portion of the transfer roller 11 as a conveyance guide. It is stored in the member 15.

As shown in FIG. 1, the transfer roller 11 may be supported rotatably but immovably in position with respect to the transport guide member 15, but the transport guide member 15 is at the position shown in FIG. In a certain state, when the transfer roller 11 is movably supported by the conveyance guide member 15 in a direction in which the transfer roller 11 is moved toward and away from the photoconductor 1, and the toner image transfer operation is not performed, for example, an image forming apparatus is used. The transfer roller 11 is brought to a position separated from the photoconductor 1 by a contacting / separating means (not shown) having a spring or the like provided on the main body side, and when the transfer operation of the toner image is performed, the pressing force by the contacting / separating means is applied. By the action, the transfer roller 11 can be pressed against the photoconductor 1 via the transfer paper.
When the toner image is transferred, the transfer roller 11 is brought into pressure contact with the photoconductor 1 via the transfer paper 9 by the contacting / separating means, and the transfer roller 11 is separated from the photoconductor 1 at a time other than the time when the toner image is transferred. The deterioration of the body 1 and the transfer roller 11 is prevented.

Below the transfer guide body 16, a protective cover opening / closing means 23 for opening / closing an image carrier protective cover 31 described later is provided. This protective cover opening / closing means 23
As shown in FIGS. 1 and 9, a stay shaft 24 extending in parallel with the photoconductor 1 and the transfer roller 11 and a pair of release cams 25, 25 integrally fixed to each end of the stay shaft 24 in the longitudinal direction thereof.
An image carrier protective cover release bar 26 whose base end is fixed to one release cam 25, an operation lever (operation knob) 27 fixed to the other release cam 25, and a pair of rollers 2
8 is mounted, and the legs are composed of a conveyance guide member release bar 29 fixed to the release cams 25, 25. The respective shaft ends of the stay shaft 24 are rotatably fitted to the machine side plate 21 shown in FIG. 1 and the front machine side plate (not shown).

The image carrier protective cover 31 covers the image carrier, in this example, the photoconductor 1, as will be described later. The image carrier protective cover 31 is as shown in FIGS. 1 and 5. , A cover portion 31A having a circular arc-shaped cross section and extending parallel to the photoconductor 1, and arm portions 31B and 31C integrally formed at each longitudinal end of the cover portion 31A. Hole 3 drilled on the tip side of parts 31B and 31C
1B ₁ and 31C ₁ are fitted on the shaft 1a of the photoconductor 1 so as to be relatively rotatable. In this way, the image carrier protection cover 31
Is rotatable about the photoconductor shaft 1a and constitutes a component of the process cartridge 10. The image carrier protective cover 31 can be pivotally supported on other elements of the process cartridge 10, such as the cartridge case 18, so as to be swingable.

Returning to FIG. 1, the arm spring 31B of the image carrier protection cover 31 has a tension spring 3 as an example of a biasing means.
2 is hung on one end, and the other end is cartridge case 1
8 (FIG. 4), the elastic force of the spring 32 urges the image carrier protective cover 31 to rotate in the clockwise direction in FIG. 1 around the photoconductor shaft 1a. Are blocked by the image carrier protective cover release bar 26. Image carrier protective cover release bar 26 shown in FIG.
However, by pressing the bent portion 31D formed on the arm portion 31C of the image carrier protection cover 31, the rotation of the image carrier protection cover 31 is blocked, and the opening 19D is thereby opened.
Is open.

In the state shown in FIG. 1, the conveyance guide member 15
Is pushed up by the rollers 28 of the conveyance guide member release bar 29, and in this state, the transfer roller 11 supported by the conveyance guide member 15 is held at a position facing the photoconductor 1. The cover portion 31A of the image carrier protection cover 31 is located on the right side of the drawing from the transfer portion 12,
That is, it is placed at a position retracted toward the developing device 6 (FIG. 4). In this state, as shown in FIG. 4, the opening 19 of the cartridge case 18 is open.

In the state shown in FIG. 1, as described above, the transfer roller 11 is brought into pressure contact with the photosensitive member 1 via the transfer paper to perform the transfer operation of the toner image. At this time,
The transfer guide member 15 is placed at a transfer guide member set position in which the transfer roller 11 is positioned at a position facing the photoconductor 1 together with the transfer roller 11 which is one configuration example of the transfer device. That is, the transport guide member 15 is
The transfer sheet 9 is held at the position shown in FIG. 4, and at this position, when the transfer sheet 9 that has come out of the transfer section 12 after the transfer is sent toward the fixing device 17, the transfer sheet 9 is guided.

While the image forming process is being performed,
For example, when the transfer paper 9 (FIG. 4) is jammed at the transfer section 12, or when the process cartridge 10 (FIG. 4) is attached to or detached from the image forming apparatus main body while the image forming process is not being performed, Further, when performing maintenance work or the like, the transfer roller 11 can be moved downward. That is, in FIG. 1, the operator grasps the operation lever 27 (FIG. 9) by hand,
When the entire protective cover opening / closing means 23 is rotated counterclockwise in the figure around the center of the stay shaft 24, the conveyance guide member releasing bar 29 gradually tilts to the left side in the figure, and the roller 28 is shown in the figure. Move to the lower left. Along with this, the conveyance guide member 15 supported by the roller 28 pivots around the pivot 22 in the clockwise direction in FIG. 1, and the transfer roller 11 separates from the photoconductor 1. FIG. 2 shows a state in which the transport guide member 15 is being rotated, and the transport guide member 15 overlaps the transfer guide body 16 inside thereof.

At the same time, the image carrier protective cover release bar 26 shown in FIG. 1 is retracted in the direction away from the transfer roller 11, and the image carrier protective cover 31 is moved by the force of the spring 32 to move the photosensitive member 1 of the photoconductor 1 accordingly. It rotates around the shaft 1a, and the cover 31
As shown in FIG. 2, A comes to a portion located in the transfer portion 12 (FIG. 1). In this state, the opening 19 (FIG. 4) of the cartridge case 18 is closed. The transfer guide body 16
2), the conveyance guide member 15 remains held at the initial position shown in FIG. 1 during the above-described turning (when turning from the position shown in FIG. 1 to the position shown in FIG. 2).

The protective cover opening / closing means 23 shown in FIG.
When the stay shaft 24 is further rotated counterclockwise around the center of the stay shaft 24, the roller 28 of the conveyance guide member release bar 29 is separated from the conveyance guide member 15 and is separated from the conveyance guide member 15. While the transfer guide body 16 is both supported by the release cam 25, the transport guide member 15 and the transfer guide body 16 integrally start to rotate around the pivot 22, and the operation lever 27 causes the stopper pin 33 shown in FIG. The conveyance guide member 15 and the transfer guide body 16 are placed at the positions shown in FIG. A spring (not shown), which is a so-called fulcrum crossing spring or a toggle spring, is locked to the protective cover opening / closing means 23, and the spring of the protective cover opening / closing means 23 is shown in FIG. When it is in the open position, it is urged clockwise around the center of the stay shaft 24 in the figure and is held in this position by hitting a stopper (not shown). On the contrary, when the protective cover opening / closing means 23 occupies the position shown in FIG. 3, this means 23 is urged in the counterclockwise direction in FIG. 3 by the spring and hits the stopper pin 33 to cause the opening / closing means 23 to move. Held in position.

Further, the releasing cam 25 has a cam shape so that the transfer guide body 16 can move as described above. Further, as shown in FIG. 3, after the image carrier protective cover 31 is rotated by the force of the spring 32 to the position where the cover portion 31A closes the opening 19, the protective cover 31 is moved to its position by a stopper member (not shown). You can stop at.

With the conveyance guide member 15 placed in the position shown in FIG. 3, the space between the photoconductor 1 and the transfer roller 11 is largely opened. That is, the upper portion of the transport guide member 15 is opened, and the transfer paper transport path is largely opened. In such a state, when the transfer paper is jammed in the vicinity of the transfer portion, when the maintenance work is performed, or when the process cartridge is replaced, the jammed paper is easily removed or the maintenance work is performed. The replacement work of the process cartridge can be easily performed.

Now, tentatively, the photoconductor 1 and the transfer roller 1
1 and the process cartridge 10 is opened.
Assuming that there is no cover member for closing the opening 19 of the, it is possible to remove jammed paper or perform maintenance work.
It becomes easy for a hand, a tool, or the like to come into contact with the photoconductor 1. When the hand or the like comes into contact with the photoconductor 1, the surface of the photoconductor is scratched, or the oil on the fingers adheres to the surface of the photoconductor, which deteriorates the image quality and shortens the life of the photoconductor.

The process cartridge 10 is taken out of the image forming apparatus main body by pulling the process cartridge 10 toward the front side of the image forming apparatus main body or by lifting the process cartridge 10 upward, and the process cartridge 10 is placed on the mounting portion. When there is no cover member for closing the photoconductor, the photoconductor 1 in which some protrusion on the mounting portion faces the cartridge opening
In some cases, the surface of the photoconductor is damaged.

Therefore, an image forming apparatus having a structure in which a predetermined cover member (shutter member) is opened and closed with respect to the opening 19 by a manual operation has been conventionally provided. If the user forgets to close the opening when performing jam processing or the like, the surface of the photoconductor will be inadvertently scratched with a finger. Further, it is very troublesome in terms of work to close the cover member one by one when removing jams or removing process cartridges.

On the other hand, in the present embodiment, the recording medium conveying path below the process cartridge 10 is opened when performing jam processing, maintenance work, or removing the process cartridge 10. However, the conveyance guide member 15 is necessarily displaced, but the image carrier protection cover 31 closes the opening 19 in conjunction with this movement, so that even if a jam process or the like is performed, the hand or the like will be on the surface of the photoconductor. It is possible to prevent the surface from being scratched or scratched. Then, it is not necessary to perform the troublesome work of manually closing the image carrier protection cover 31. In any case, the protection of the photoconductor during jam handling, maintenance work, and process cartridge removal can always be guaranteed.

In FIG. 1, when a jam occurs on the transfer paper at the transfer unit 12, the transfer unit 1 of the transfer paper is
The part extending from 2 to the tip may cling to the peripheral surface of the photoconductor 1 and stick to the peripheral surface. In such a case, the cover portion 31 of the image carrier protection cover 31
When A enters the transfer portion 12, the cover portion forcibly peels off the stuck transfer paper portion from the photoconductor 1. That is, the attached transfer paper portion can be peeled off by the cover portion 31A without touching the photoreceptor 1 with the hand.

As described above, the transport guide member 15
Is a conveyance guide member setting position where the transfer roller 11 is positioned at a position facing the photoconductor 1 as shown in FIG.
The photoconductor 1 and the transfer roller 11 are separated from each other, and the space between them is opened, and the photoconductor 1 and the transfer roller 11 are displaceably supported at respective positions such as the conveyance guide member release position shown in FIG.

Here, when the jam processing, the maintenance work, the loading of the process cartridge into the image forming apparatus, etc. are completed, the conveyance guide member 15 is positioned at the conveyance guide member set position together with the transfer guide body 16. To do so, perform the following operation.

In FIG. 3, when the operator grabs the operating lever 27 by hand and rotates the protective cover opening / closing means 23 around the center of the stay shaft 24 in the clockwise direction in the figure, first, the transfer guide body is first formed. 16 together with the transport guide member 15 is lifted by the release cam 25,
It rotates around 2 in the counterclockwise direction, and they come to the positions shown in FIG. 2, and one transfer guide body 16 stops. Next, the transport guide member 15 is replaced by the transport guide member release bar 2
While being pushed up by the roller 28 of No. 9, it is subsequently rotated counterclockwise and placed at the initial position (transfer paper transport guide position) shown in FIG.

On the other hand, the protective cover opening / closing means 2 shown in FIG.
While rotating 3 around the stay shaft 24 in the clockwise direction, the image carrier protective cover release bar 26 first causes the bent portion 31D of the image carrier protective cover 31 as shown in FIG.
The image-bearing-member protective cover release bar 26 pulls the image-bearing-member protective cover 31 around the photoconductor shaft 1a against the elastic force of the spring 32, and counterclockwise in the figure, the initial stage shown in FIG. Rotate to the position. At the time of such rotation, the cover portion 31A is displaced around the photoconductor 1 from the opening closed position to the opening open position (position in FIG. 1). In this way, the opening 19 of the process cartridge 10 is opened as shown in FIGS. 1 and 4, and the image forming process can be executed. The image carrier protective cover 3
1 is placed at the opening open position shown in FIG. 1 before the transfer roller 11 reaches a position facing the photoconductor 1 as shown in FIG.

As described above, in association with the displacement operation of the transport guide member 15, when the transport guide member 15 is at the set position (transfer paper transport guide position) shown in FIG. 1, the cartridge case 18 of the process cartridge 10 is provided.
3 is opened, and the conveyance guide member 15 is opened in FIG.
When in the release position shown in FIG.
The image-bearing-member protective cover 31 that is displaced so that the opening 19 thereof is closed is provided as a component of the process cartridge. The opening / closing operation of the image carrier protective cover 31 is restricted and executed by the protective cover opening / closing means 23 described above as an example.

The present invention can be applied to an image forming apparatus in which the transfer device is not a transfer roller but a transfer charger that performs corona discharge. Even in this case, the transfer charger is used as the conveyance guide member 15. By providing, the gap between the photoconductor 1 and the transfer charger is largely opened, so that the sham treatment or the like can be easily performed.

By the way, when the transfer roller 11 is used as the transfer device and placed at a position in contact with the photosensitive member via the transfer paper at the time of transfer, the transfer roller 11 is retracted downward as shown in FIG. , Photoconductor 1 and transfer roller 11
If the upper part of the transfer roller 11 is left exposed outside the conveyance guide member 15 in a state where the space between and is opened, it is possible to perform jam processing, maintenance work, and replacement of the process cartridge 10. The hand easily comes into contact with the transfer roller 11.

When a hand or the like comes into contact with the exposed portion of the transfer roller 11, the surface of the transfer roller 11 is easily scratched by a nail or the like, and when the oil of the finger adheres to the surface of the transfer roller, the transfer function is adversely affected. Exert. In any case, the image quality may be deteriorated or the life of the transfer roller 11 may be shortened.

In order to deal with such various points, the upper portion of the transfer roller 11 may be covered with a dedicated cover member. In this case, however, the opening / closing operation of the cover member is forgotten. Sometimes. Therefore, if a transfer roller protection cover is attached to the conveyance guide member 15 or the transfer guide body 16 and the transfer roller protection cover and the image carrier protection cover are configured so as to interlock with each other, the transfer roller protection cover You will not forget to open and close it, and you will not have to perform such troublesome opening and closing operations. In this case, of course, when jamming,
The transfer roller as well as the photoconductor can be protected at the same time.

In FIG. 1, a transfer roller protection cover 34 is pivotally supported by a transfer shaft 16 on a transfer guide body 16 by a pivot shaft 35. The transfer roller protection cover 34 has a cover portion 34A extending in the axial direction of the transfer roller 11,
The overall structure is as shown in FIG. Further, one end of a tension spring 36, which is an example of a biasing means, is locked to the transfer roller protection cover 34, and the other end of this spring 36 is locked to the transfer guide body 16, and by the force of the spring 36, The cover portion 34A is rotationally biased in a direction toward the transfer roller 11. At both ends of the cover portion 34A of the transfer roller protection cover 34, as shown in FIG.
4g and 34g are provided, respectively.

On the other hand, as shown in FIG. 5, the gear portion 31 is also provided at both ends of the cover portion 31A of the image carrier protective cover 31.
g and 31g are provided, and the gear portion 31g and the gear portion 34g of the transfer roller protection cover 34 mesh with each other as shown in FIG. In addition, the gear portion 31
As for g and 34g, illustration of a specific gear configuration is omitted in FIGS. 1 to 3 for convenience.

In FIG. 1, the transport guide member 15 is placed at the set position. In this state, the bias terminal of the transfer roller 11 and the connection terminal (receptacle) (not shown) on the image forming apparatus main body side. Are connected to each other, and a bias voltage for transferring a toner image can be applied to the transfer roller 11. Further, the transport guide member 15
With the set, the gear part 31 of both covers 31 and 34
g and 34g mesh with each other.

As described above, the protective cover opening / closing means 23
1 is rotated from the position shown in FIG. 1 to the position shown in FIG. 2, the image carrier protective cover 31 is rotated clockwise by the force of the tension spring 32. At this time, since the gear portions 31g and 34g are meshed with each other, the transfer roller protection cover 34 is also rotated counterclockwise around the pivot 35 in association with the image carrier protection cover 31, and the transfer roller 11 is rotated. The cover portion 34A on the right side in the drawing enters between the photoconductor 1 and the transfer roller 11 and covers the upper portion of the transfer roller 11 as shown in FIG. That is, the opening 19 of the cartridge case 18 of the process cartridge 10 described above is closed by the image carrier protection cover 31, and at the same time, the transfer roller 1
1 is the cover portion 34A of the transfer roller protection cover 34
Is covered by.

When the protective cover opening / closing means 23 is further rotated to the position shown in FIGS. 2 to 3, the gear portion 34g separates from the gear portion 31g during this period. In the state shown in FIG.
At the same time as the gap between the photoconductor 1 and the transfer roller 11 is wide open, the photoconductor 1 and the transfer roller 11 are separated from each other by the respective protective covers 3
1, 34 respectively protected.

As described above, since the photoconductor 1 and the transfer roller 11 are respectively protected, the photoconductor 1 and the transfer roller 11 are protected from each other during jamming, maintenance work, process cartridge replacement, etc. For both, it is possible to prevent these from getting scratches or oil on the fingers.

When the transport guide member 15 is placed at the set position (transfer paper transport guide position), the protective cover opening / closing means 23 shown in FIG. 3 is rotated clockwise to transfer the transfer guide member 15 and the transfer guide member 15. The guide body 16 is lifted to the position shown in FIG. 2, and then the transport guide member 15 is lifted to the position shown in FIG. 1 by the rollers 28 of the transport guide member release bar 29. During this time, as shown in FIG.
When 4 g meshes with the gear portion 31 g and the rotation operation of the protective cover opening / closing means 23 is continued, the image carrier protective cover release bar 26 pushes the image carrier protective cover 31, and the image carrier protective cover 31 is moved. Rotate to the position shown in FIG. At the same time, the transfer roller protection cover 34 is rotated in conjunction with the image carrier protection cover 31, and the cover portion 34A is placed at the position of FIG. 1 retracted from the position covering the upper portion of the transfer roller 11.

Incidentally, at a stage before the transfer roller 11 faces the photoconductor 1 as shown in FIG.
1 and the transfer roller protective cover 34 are set to have the displacement operation timing of each protective cover so as to end the movement to the retracted position. Can be kept out of contact with.

As described above, the portion of the transfer roller 11 on the side of the photoconductor 1, that is, the upper portion thereof, is the image carrier protective cover 3
When the conveyance guide member 15 is in the release position (FIG. 3), the transfer roller protection cover 34 that is interlocked with the displacement operation of No. 1 is closed so as not to be exposed to the outside, and the conveyance guide member 15 is set to the set position (FIG. 1). At a certain time, the transfer roller protection cover 34 is opened so as to be exposed to the outside by a retracting operation from the closed position (FIG. 3) to the position shown in FIG. In this example, the image carrier protection cover 3
1 and the gear portion 34g provided on the transfer roller protective cover 34 are interlocked with the displacement operation of the image carrier protective cover 31, and the transfer roller protective cover 34 causes the photosensitive member 1 of the transfer roller 11 to move. One example of the interlocking device that operates to open and close the part on the side of is formed. In this way, it becomes unnecessary to perform the troublesome work of opening and closing the cover member by hand to protect the photoconductor and the transfer roller as described above. You will never forget it.

Since the transfer roller protection cover 34 is attached to the transfer guide body 16, the transfer guide body 16 as well as the transport guide member 15 is manufactured by the manufacturer, a service person who performs maintenance work, or a user. However, when the transfer roller 11 is mounted on the main body of the image forming apparatus by covering the upper portion of the transfer roller 11 with the transfer roller protection cover 34, it is possible to prevent the transfer roller 11 from being touched by a hand or other foreign matter.

Further, the transfer roller protection cover 34 may be provided on the conveyance guide member 15, and even in this case, the transfer roller 1 is similarly mounted when the transfer guide body 16 is assembled.
1 can be protected. Further, the transfer guide member 15 itself may be directly moved by the protective cover opening / closing means 23 without using the transfer guide body 16. Further, by the image carrier protection cover release bar 26, the transfer roller protection cover 34 is moved instead of the image carrier protection cover 31.
The image carrier protection cover 31 may be moved by following the transfer roller protection cover 34. It suffices to operate both protective covers 31 and 34 in conjunction with the displacement operation.

In the present embodiment, the transfer guide body 16
However, since the transfer roller protection cover 34 and the transfer roller cover 34 are also pivotally swung, for example, the photosensitive member 1 and the transfer roller 1
When the gap between 1 and 1 is opened, jam processing and the like can be easily performed in a wide open space without being hindered by the transfer roller protection cover 34. On the other hand, if the transfer roller protection cover 34 is provided on the main body of the image forming apparatus, it is impossible to achieve such an effect.

The transfer roller protection cover 34 is placed at the position shown in FIG. 1 at the time of image formation. At this position, the transfer roller protection cover 34 performs the function of guiding the transfer paper before transfer. You can choose to let them do it. As described above, if the transfer roller protection cover 34 is configured to be capable of achieving a guide function in addition to the transfer roller protection function, a dedicated transfer paper transport guide member (transfer paper transport guide used before transfer is used. (Member) becomes unnecessary, and the device configuration can be simplified.

The present invention can be applied without problems to an analog type image forming apparatus of the type in which a document image is formed and projected on a photoconductor, in addition to the digital type image forming apparatus described above. Further, a toner image is transferred from a latent image carrier such as a photoconductor in addition to an image forming apparatus using a belt-shaped photoconductor, a dielectric drum or a dielectric belt as an image carrier, and the toner image is transferred onto a transfer paper. The present invention can also be applied to an image forming apparatus that uses an image carrier that is an intermediate transfer member that is transferred to a sheet.

[0062]

According to the first aspect of the invention, the conveyance guide member is always operated to open the recording medium conveyance path during jam processing, maintenance work, and process cartridge replacement. Since the image carrier protective cover moves in a manner that opens and closes the opening of the process cartridge facing the image carrier, the image carrier can be guaranteed to be protected during jam processing. It is possible to prevent the surface of the image carrier from being scratched. Further, it is not necessary to manually open and close the dedicated image carrier protecting cover member, and it is possible to avoid forgetting to open and close such member.

According to the second aspect of the present invention, in order to open the recording medium conveyance path at the time of jam processing, maintenance work, and process cartridge replacement,
In conjunction with the transport guide member that is always operated, the image carrier protective cover is displaced so as to open and close the opening of the process cartridge facing the image carrier, and at the same time, the upper part of the transfer roller is covered by the transfer roller protective cover. Since it is opened and opened by this evacuation,
During jam processing and the like, not only the image carrier but also the transfer roller can be guaranteed without fail, and the surface of the transfer roller can be prevented from being scratched. Further, it is not necessary to manually open and close the transfer roller protecting cover member together with the image bearing member protecting cover member, and it is possible to avoid forgetting to open and close such a member.

According to the third aspect of the present invention, since a dedicated conveyance guide member for guiding the recording medium is unnecessary, the configuration of the image forming apparatus can be further simplified.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional front view showing a transfer guide body swinging component provided in an image forming apparatus according to an embodiment of the present invention together with a drum-shaped photosensitive member.

FIG. 2 is an operation view from FIG. 1 showing a state where the conveyance guide member shown in FIG. 1 is rotated and the transfer roller supported by the conveyance guide member is separated from the photoconductor, while the conveyance guide member is in the middle of rotation. Is.

FIG. 3 is an operation diagram from FIG. 2 showing a state in which the conveyance guide member shown in FIG. 2 and the transfer guide body have finished rotating and the transfer paper conveyance path is opened.

FIG. 4 is a schematic sectional view of an image forming apparatus including the transfer guide body swinging component shown in FIG.

FIG. 5 is an external perspective view of an image carrier protection cover that protects a photoreceptor.

6 is an external perspective view of the image carrier protection cover shown in FIG. 5 as viewed from another direction.

FIG. 7 is an external perspective view showing a transfer guide body together with a conveyance guide member.

FIG. 8 is an external perspective view showing a transfer guide body together with a transfer roller protection cover displaced to a transfer roller protection position, a conveyance guide member, and the like.

FIG. 9 is a perspective view showing an example of a protective cover opening / closing means.

[Explanation of symbols]

 10 Process Cartridge 11 Transfer Roller 15 Transport Guide Member 18 Cartridge Case 19 Opening 31 Image Carrier Protective Cover 34 Transfer Roller Protective Cover

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 15/02 103 21/00 350

Claims (3)

[Claims] 1. A process cartridge, which has at least an image carrier and a cartridge case in which the carrier is assembled, is detachably supported with respect to an image forming apparatus main body, and the process cartridge is formed on the image carrier. A transfer device for transferring the toner image to the recording medium and a conveyance guide member for guiding the recording medium are provided, and an opening is formed in the cartridge case so that the image carrier can face the transfer device. In the image forming apparatus, the transfer guide member as well as the transfer device is set at a transfer guide member set position where the transfer device is positioned at a position facing the image carrier, and the image carrier and the transfer device are separated from each other. The transfer guide member is displaceably supported at each position of the transfer guide member release position where the space is opened, and the transfer guide member is set in association with the displacement operation of the transfer guide member. Of the process cartridge, the opening of the cartridge case is opened when the transfer guide member is in the open position, and the opening of the cartridge case is closed when the transport guide member is in the release position. An image forming apparatus provided as. 2. The transfer device is configured as a transfer roller which is placed at a position in contact with the image carrier through the recording medium at the time of transferring the toner image, and the transfer roller leaves the part on the image carrier side. The portion of the transfer roller on the image carrier side, which is provided inside the transport guide member, is exposed to the outside when the transport guide member is in the release position by the transfer roller protection cover that is interlocked with the displacement operation of the image carrier protection cover. The image forming apparatus according to claim 1, wherein the image forming apparatus is closed so as not to be exposed, and is opened so as to be exposed to the outside by the retracting operation of the transfer roller protection cover from the closed position when the transport guide member is at the set position. . 3. The image forming apparatus according to claim 2, wherein the transfer roller protection cover also serves as a conveyance guide function for the recording medium.