JPH05134485A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a transfer member or a destaticizing stylus in an image forming part from being exposed when an opening/closing member against the device main body is opened. CONSTITUTION:The transfer roll 11, the destaticizing stylus 12, and a guide cover 16 are provided on the device main body 1 side, and a photosensitive drum 3 and a pushing lever 9 are provided on the opening member 2 side. When the opening member 2 is moved in the direction R1, the mold lever 20 is inclined in the direction R7 by the pushing lever 9, a guide cover 16 is moved in the right direction of the diagram by having a metal lever 19 rotated in the direction of R2, and carrying of the recording material is guided by a guide cover 16 along with a carrying guide 13. On the other hand, when the opening member 2 is opened, the guide cover 16 is returned to a cover position 16a by restoring force of the mold lever 20, and the transfer member 11 and the destaticizing stylus 12 have their tops covered and protected by this. The movement of the guide cover 16 is carried out automatically, linked with the opening/ closing action of the opening member 2 with the pushing lever 9 protruding from it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer in which an image carrier and a transfer member can be brought into contact with and separated from each other, and more specifically, an image forming unit is opened for clearing a paper jam. In this case, the present invention relates to an image forming apparatus in which a part of the transport guide moves in conjunction with the opening operation to cover the transfer member.

[0002]

2. Description of the Related Art Conventionally, an image carrier and a transfer member that is in pressure contact with the image carrier are provided, and a recording material is passed between the both.
At this time, an image forming apparatus is known in which a bias voltage is applied to a transfer member to transfer a toner image on the image carrier side to a recording material.

In such an apparatus, a roller-shaped member or a belt-shaped member is generally used as a transfer member, and as its material, a conductive filler such as conductive carbon, graphite or metal powder is contained in a rubber or resin matrix. Those whose resistance has been adjusted by dispersion, those whose resistance has been adjusted by adding a plasticizer, a low molecular weight liquid rubber, and a surfactant to a rubber or resin matrix, and JP-A-63-15
A carbon black-containing crosslinked silicon rubber pulverized product as disclosed in Japanese Patent No. 6858 is dispersed in silicon rubber to adjust resistance. In addition to this, there is known a transfer roller having a multilayer structure in which a relatively stable low resistance layer of 10 ⁴ Ωcm or less and a high resistance layer of 10 ¹⁰ Ωcm or more are combined.

FIG. 16 is a schematic side view showing a typical example of such an image forming apparatus.

It has an axis line in the direction perpendicular to the plane of the drawing and has an arrow X in the drawing.
The surface of the cylindrical photosensitive drum (image carrier) 3 rotating in the direction is uniformly charged by the power source 50 through the charging roller (charger) 5, and then the image is written by the image information writing means L. Image information is applied to the charged surface by a modulated laser beam, slit exposure, or the like to form an electrostatic latent image.

Next, toner (developer) is supplied to the latent image by the developing device 6 to form a toner image.

When the toner image reaches a transfer portion which is a nip portion between the transfer roller (transfer member) 11 and the photosensitive drum 3 as the photosensitive drum 3 rotates, the recording material P is timed with the toner image. Also passes the transport guide 13,
Reach this transcription site. At this time, a transfer bias is applied to the transfer roller 11 to apply a charge having a polarity opposite to that of the toner to the back surface of the recording material P, and the toner image on the photosensitive drum 3 is transferred to the recording material P. After that, the excess charge on the back surface of the recording material P is removed by the charge elimination needle 12. Further, the recording material P is conveyed along the conveyance guide 15 to a fixing device (not shown).

In the illustrated apparatus, an OPC photosensitive member is used as the photosensitive drum 3, and the process speed is 23 mm /
sec, the charging roller 5 is pressed against the photosensitive drum 3 to negatively charge the same, and the charging roller 5 to which a superimposed voltage of AC voltage and DC voltage is applied to negatively charge the photosensitive drum 3 is also transferred to the photosensitive drum 3 by pressure. Then, the transfer roller 11 made of the above-mentioned material that gives a positive charge to the back surface of the recording material P was used. The resistance value of the transfer roller 11 is such that the volume resistance is 10 ⁶ Ωcm to 1 in consideration of improvement of transferability in a low humidity environment and prevention of damage to the photosensitive drum 3 due to a transfer electric field.
It is known that a semiconductive region of 0 ¹² Ωcm is preferable.

The image forming apparatus using such a contact transfer system is advantageous in terms of cost because it does not require a high voltage power source, as compared with the one using a corona discharger which has been widely used in the past, and is advantageous in cost. Since there is no need to dispose wires as well, there is no trouble due to dirt on them, there is no generation of ozone or nitrides due to high-voltage discharge, and there is little deterioration of the photosensitive drum or image quality due to these. There are many advantages.

An image forming apparatus in which the photosensitive drum 3, the charging roller 5, the developing device 6, the cleaner 7 and the like are integrally formed into a cartridge and the process cartridge is detachably mounted for use is also widely known. ..

[0011]

However, in the above-mentioned conventional example, the upper door (not shown) of the main body is opened to open the image forming portion when the process cartridge is inserted or the paper jam is handled, so that the insertion, the processing, etc. can be easily performed. However, since the transfer roller 11 and the charge elimination needle 12 are exposed and exposed at this time, there are the following drawbacks. Since the user may touch the transfer roller, the transfer roller must be grounded when the upper door of the main body is opened. The transfer roller with a resistance in the semi-conductive area (10 ⁶ Ωcm to 10 ¹² cm) adjusts the resistance value by dispersing conductive carbon, graphite, metal powder or other conductive filler in a rubber or resin matrix. Moreover, when the user touches the transfer roller and pressurizes it, the positional relationship of the dispersed conductive fillers changes, and the resistance value also changes. Therefore, transfer unevenness occurs and the image deteriorates. When the user's hand touches the transfer roller when the hand is soiled with sweat or oil, the soil adheres to the transfer roller and further adheres to the photosensitive drum, resulting in image unevenness. If the upper side door of the main body is kept open for a long time, dust is accumulated on the transfer roller, causing uneven transfer. If the upper door of the main body is kept open for a long period of time, dust will accumulate on the static elimination needle, resulting in uneven static elimination and defects. The user may get injured by touching the charge elimination needle. And the like.

Therefore, in the present invention, a guide cover that interlocks with the movement (opening and closing) of the moving member (upper door of the main body) is provided,
The guide cover forms a part of the conveyance guide when the moving member is closed, and covers the transfer member (transfer roller) or the like when the moving member is opened. Protects the transfer member,
An object of the present invention is to provide an image forming apparatus that solves the conventional problems.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes an apparatus main body for holding one of an image carrier and a transfer member, and the above-mentioned apparatus for holding the other. A moving member that is movably arranged with respect to the main body,
An image forming position including a conveyance guide that guides a recording material that is conveyed near the transfer member, the moving member abutting the image carrier and the transfer member to form an image, and the image carrier. In an image forming apparatus having a retracted position in which a body and a transfer member are separated from each other and an image forming unit is opened, the image forming apparatus moves between a guide position forming a part of the conveyance guide and a cover position covering the transfer member. A guide cover that is freely arranged and a linkage mechanism that moves the guide cover to the guide position and the cover position, respectively, corresponding to the moving member taking the image forming position and the retracted position. , Is characterized.

In this case, the linkage mechanism is provided on one of the apparatus body and the moving member and is connected to the guide cover, and on the other side, the moving member is moved. Accordingly, a pressing member that engages and disengages with the engaging member may be provided.

Further, the moving member may be a process cartridge.

[0016]

According to the above construction, when the moving member is moved to the image forming position with respect to the main body of the apparatus, the linkage mechanism positions the guide cover at the guide position which constitutes a part of the recording material conveyance guide. On the other hand, when the moving member is moved to the retracted position for clearing a paper jam, for example, the linkage mechanism positions the guide cover at the cover position that covers the transfer member and prevents its exposure. That is, the guide cover operates in conjunction with the moving member via the linkage mechanism, and particularly covers and protects the transfer member when the moving member retracts and the image forming unit is opened.

When the linking member includes the engaging member and the pressing member, which are separately arranged in the apparatus main body and the moving member, the moving member is moved with respect to the apparatus main body to press the engaging member and the pressing member. The member engages with each other to operate the engaging member, whereby the cover member connected to the engaging member performs a predetermined operation of moving between the cover position and the guide position.

Further, when the moving member is the process cartridge, the mounting and demounting of the process cartridge corresponds to the moving operation of the moving member, that is, the mounting and demounting of the process cartridge causes the guide cover to automatically move to the cover position and the guide position. Take and.

[0019]

Embodiments Embodiments will be described below with reference to the drawings.

1 to 5 show a first embodiment of an image forming apparatus according to the present invention, and FIG. 5 shows an outline thereof.

The image forming apparatus comprises an apparatus main body 1 and an opening / closing member (moving member) 2 which can be opened / closed (moved) with respect to the apparatus main body 1.

The opening / closing member 2 has a photosensitive drum 3 as an image carrier, a charger 5 for uniformly charging the photosensitive drum 3, and an exposing means for exposing the photosensitive drum 3 after charging to form an electrostatic latent image ( (Not shown), a developing device 6 for developing an electrostatic latent image with toner (developer), a cleaner 7 for removing residual toner, and the like are provided. A push lever (pressing member) 9 is provided at the lower end of the opening / closing member 2 so as to form a linking mechanism together with a mold lever described later. The opening / closing member 2 as a whole is movable with respect to the apparatus main body 1 about the shaft 10 in the direction of arrow R1 and is retracted to open the image forming unit inside the apparatus main body 1 (solid line in FIG. 5). 2a and an image forming apparatus (two-dot chain line in the figure) 2b that closes the image forming unit.

A transfer roller (transfer member) 11 for sandwiching the recording material P with the photosensitive drum 3 and transferring the toner image on the photosensitive drum 3 to the recording material P is arranged in the apparatus main body 1. Immediately downstream of the transfer roller 11, a charge eliminating needle 12 is arranged to remove an excess charge on the back surface of the recording material P. Guide members 13 and 15 that guide the conveyance of the recording material P from the lower surface side are provided on the upstream side and the downstream side of the transfer roller 11, respectively.
A guide cover 16 is arranged above the transfer roller 11. As shown in FIGS. 1 and 2, the guide cover 16 is formed of a plate-shaped member having a size large enough to cover the transfer roller 11 and the charge elimination needle 12 from above, and the base end portion thereof includes the shaft 17. It is connected to a metal lever 19 which can swing in the directions of arrows R2 and R3 at the center. The metal lever 19 is biased in the R3 direction by a biasing member (not shown), and its position is regulated by a mold lever (engaging member) 20. The mold lever 20 is rotatably supported by a holding member 21 on the apparatus body 1 side, and as shown in FIG.
5 (FIG. 1). Mold lever 20
1 assumes the standing posture shown in FIG. 1 in a natural state, and at this time, the tip of the mold lever 20 is moved to the metal lever 19
The guide cover 16 is held at the cover position 16a shown in FIG. 1 by abutting against and positioning the metal lever 19. On the upper part of the mold lever 20, there is formed an engaging surface 20a having a gently curved surface with which the push lever 9 on the opening / closing member 2 side is in sliding contact. The guide cover 16 is
It is assumed that the metal lever 19 moves in accordance with the rotation of the metal lever 19 in the direction of the arrow R2, but also moves to the guide position 16b shown in FIG. 3 while maintaining a substantially horizontal posture.

Next, the operation of the first embodiment will be described with reference to FIGS. 1, 3 and 5.

For example, when the recording material P is clogged between the transfer roller 11 and the photosensitive drum 3, it is
The opening / closing member 2 is opened to the retracted position 2a (solid lines in FIGS. 1 and 5), the transfer roller 11 and the photosensitive drum 3 are separated from each other, and the image forming unit is opened, so that the recording material P is easily removed. You can At this time, the mold lever 20 is
The metal lever 1 is in the upright posture and is biased in the R3 direction.
9 contacts the tip of the mold lever 20 to regulate its position, and the guide cover 16 occupies the cover position 16a. As a result, the transfer roller 11 and the static elimination needle 12 are covered by the guide cover 16 at the cover position 16a,
There is no fear that a user or the like will carelessly touch the transfer roller or the charge elimination needle during the jam processing.

Subsequently, when the opening / closing member 2 is closed with respect to the apparatus main body 1 and positioned in the image forming apparatus (solid line in FIG. 3, dashed line in FIG. 5) 2b, the push lever 9 on the opening / closing member 2 side is closed.
Engages with the engaging surface 20a of the mold lever 20 on the apparatus body 1 side, and the mold lever 20 is rotated and tilted in the direction of arrow R7. Due to the inclination of the mold lever 20 in the direction of arrow R7, the metal lever 19 abutting on the same is also inclined in the direction of R2, whereby the guide cover 16 at the cover position 16a slides to the guide position 16b. fall back. The guide cover 16 at the guide position 16b faces the conveyance guide 13 and guides the conveyance of the recording material P from above and below in cooperation with the conveyance guide 13. The guide cover 16 covering the transfer roller 11 and the like is retracted, and the photosensitive drum 3 on the opening / closing member 2 side comes into contact with the transfer roller 11 on the apparatus main body 1 side from above, so that the recording material P as a whole is formed.
It is possible to form an image on the.

As described above, the guide cover 16 is interlocked with the opening / closing operation of the opening / closing member 2, and the transfer roller 11 and the charge elimination needle 12 are interlocked.
Since the cover position 16a that covers and protects the sheet and the guide position 16b that forms a part of the conveyance guide can be automatically set, the user or the like mistakenly selects the transfer roller 11, the static elimination needle 12 or the like during the jam processing. It is possible to prevent danger and deterioration of image quality due to touch.

Next, a second embodiment will be described with reference to FIGS. 6 and 7.

In this device, a metal lever 19 and a mold lever 20 are arranged on the downstream side of the transfer roller 11 on the apparatus main body 1 side. The push lever 9 on the opening / closing member 2 side
When engaged with the engagement surface 20a of the mold lever 20, the mold lever 20 is inclined forward (downstream in the traveling direction of the recording material P, that is, on the left side in FIGS. 6 and 7). Due to this inclination, the metal lever 19 also inclines forward, whereby the guide cover 16 moves to the front guide position 16b and constitutes a part of the downstream transport guide.

A third embodiment is illustrated in FIGS. 8-12.

In this example, as shown in FIG. 8, the process cartridge 2 is used as the moving member.

As is well known, the process cartridge 2 is a cartridge in which the photosensitive drum 3, the charging device 5, the developing device 6, the cleaner 7 and the like are integrally formed, and is detachably mounted to the apparatus main body 1 for use. In the mounted image forming apparatus, the photosensitive drum 3 comes into contact with the transfer roller 11 on the apparatus body 1 side (FIG. 11). On the other hand, when the process cartridge 2 is retracted to the retracted position 2a (FIGS. 8 and 9), the transfer roller 11 is exposed.

Therefore, the transfer roller 11 on the apparatus main body 1 side,
An arrow R is provided above the static elimination needle 12 by a guide member (not shown).
A guide cover 16 that is slidable in 9 directions is provided.
The guide cover 16 takes a cover position 16a (FIG. 1) in a natural state by a spring (not shown),
When the push lever 9 protruding from the lower end of the process cartridge 2 is engaged, the push lever 9 slides forward and moves to the guide position 16b.
(Fig. 11) to form a part of the conveyance guide. In this embodiment, the push lever 9 directly moves the guide lever, and both of them constitute a linkage mechanism. When the process cartridge 2 is removed,
The guide cover 16 returns to the cover position 16a and covers the transfer roller 11 and the charge elimination needle 12 from above to effectively protect them.

A fourth embodiment is shown in FIGS. 13 to 15.

In this embodiment, unlike the previous three embodiments, the photosensitive drum 3, the push lever 9 and the like are arranged on the apparatus main body 1 side, and the opening / closing member 2 is opened and closed in the lateral direction (R1 direction).
The transfer roller 11, the guide cover 16 and the like are arranged on the side.

In this case as well, the opening / closing member 2 is replaced by the photosensitive drum 3.
2a where the transfer roller 11 and the transfer roller 11 are separated from each other (FIG. 13)
When the guide cover 16 is movably supported by the rotatable metal lever 19, the guide cover 16 takes the cover position 16a (FIG. 14) that covers the transfer roller 11 and the charge eliminating needle 12, while
When the opening / closing member 2 is in the image forming apparatus in which the photosensitive drum 3 and the transfer roller 11 are in contact with each other, the guide cover 16 takes the cover position 16b (FIG. 15) and serves as a part of the conveyance guide of the recording material P. To be done. 23 and 25 in the figure
Is a registration roller that feeds the recording material P to the nip portion between the photosensitive drum 3 and the transfer roller 11 at a predetermined timing.

In the above-mentioned first to fourth embodiments, the push lever 9 for operating the guide cover 16 is used.
The linkage mechanism such as is not limited to disposing one set in the vicinity of one end of the transfer roller 11, but disposing two sets in the vicinity of both ends of the transfer roller 11 as necessary. You can also

Further, the transfer roller 11 may be arranged on the apparatus main body 1 side or the moving member 2 side. Accordingly, the photosensitive drum 2 may be provided on the member on which the transfer roller 11 is not provided. In this case, the guide cover 16 covering the transfer roller 11 is arranged on the same member side as the transfer roller 11, and the push lever 9 for operating the guide cover 16 is arranged on the other member side. That is, when the moving member (opening / closing member, process cartridge) 2 is retracted from the apparatus main body 1, the transfer roller 1
The image forming portion near 1 is exposed. At this time, the guide cover 1 is interlocked with the retracting operation of the moving member 2.
As long as 6 can cover the transfer roller 11 and the charge elimination needle 12 to effectively protect them, the configuration is not limited to the configurations described in the first to fourth embodiments.

For example, in these embodiments, the guide cover 16 serves both as a cover member for the transfer roller 11 and the like and as a guide member for the recording material. Not limited to, guide cover 1
It goes without saying that 6 may not function as a guide member but may function only as a cover member.

[0040]

As described above, according to the present invention,
A guide cover that can take a guide position that forms a part of the transport guide and a cover position that covers the transfer member and the like;
By disposing the guide cover at the cover position by a retracting operation of the moving member with respect to the apparatus main body and a linking mechanism including a push lever, the moving member is retracted to form an image when, for example, a paper jam occurs. Since the guide cover automatically covers and protects the transfer member etc. when the section is opened, the user etc. can be effectively prevented from touching it during jam processing etc. It is possible to prevent damage to the image and defective images.

[Brief description of drawings]

FIG. 1 is a side view schematically showing the vicinity of a transfer roller according to a first embodiment.

FIG. 2 is a front view of the same.

FIG. 3 is an explanatory diagram of the same operation.

FIG. 4 is a front view of the same.

FIG. 5 is a side view schematically showing the image forming apparatus according to the first embodiment.

FIG. 6 is a side view schematically showing the vicinity of a transfer roller according to a second embodiment.

FIG. 7 is an explanatory diagram of the same operation.

FIG. 8 is a side view showing an outline of an image forming apparatus according to a third embodiment.

FIG. 9 is a side view schematically showing the vicinity of the transfer roller.

FIG. 10 is an explanatory perspective view of the same.

FIG. 11 is an explanatory diagram of the same operation.

FIG. 12 is an explanatory perspective view of the same.

FIG. 13 is a side view showing the outline of an image forming apparatus according to a fourth embodiment.

FIG. 14 is a side view schematically showing the vicinity of the transfer roller.

FIG. 15 is an explanatory diagram of the same operation.

FIG. 16 is a side view showing an outline of a conventional image forming apparatus.

[Explanation of symbols]

 1 Device Main Body 2 Moving Member (Opening / Closing Member, Process Cartridge) 2a Retreat Position 2b Image Forming Device 3 Image Carrier (Photosensitive Drum) 9 Pressing Member (Push Lever) 11 Transfer Member (Transfer Roller) 13, 15 Transport Guide 16 Guide Cover 16a Cover position 16b Guide position 20 Engaging member (mold lever) P Recording material

Claims (3)

[Claims] 1. An apparatus main body that holds one of an image carrier and a transfer member, a moving member that holds the other and is movably disposed with respect to the apparatus main body, and conveys the vicinity of the transfer member. An image forming position at which the moving member abuts the image carrier and the transfer member to enable image formation, and the image carrier and the transfer member are separated from each other. In the image forming apparatus having the retracted position for opening the image forming unit, a guide movably disposed between a guide position forming a part of the transport guide and a cover position covering the transfer member. A cover; and a linkage mechanism that moves the guide cover to the guide position and the cover position, respectively, in response to the moving member taking the image forming position and the retracted position. Image forming device. 2. The linking mechanism is provided on one of the apparatus body and the moving member and is connected to the guide cover, and the other is provided on the other side to move the moving member. The image forming apparatus according to claim 1, further comprising a pressing member that engages and disengages with the engaging member. 3. The image forming apparatus according to claim 1, wherein the moving member is a process cartridge.