JPH066368Y2 - Electrophotographic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to an electrophotographic apparatus that functions as a copying machine, a printer, a facsimile, or a composite machine of these, in which an upper body and a lower body can be divided and opened. In particular, the present invention relates to an electrophotographic apparatus in which a process unit in which a plurality of electrophotographic process means including a photosensitive drum are unitized is attached to an upper main body side.

“Prior Art” Conventionally, for example, a device is known in which an upper body and a lower body can be divided and opened along a recording material conveyance path to further facilitate jam processing or maintenance. In order to facilitate the opening of the conveying path, the apparatus of (1) is equipped with a photosensitive drum, an exposing unit, a developing unit, a cleaning member, a charging unit, etc. which are generally located above the recording material conveying path on the upper main body side. On the other hand, a sheet feeding unit, a registration roller, located below the recording sheet conveyance path or sandwiching the conveyance path,
In many cases, a transfer unit, a fixing unit, etc. are arranged on the lower main body side.

However, if such a structure is adopted, the member that rotates by receiving the driving force from the driving source is divided into the upper body and the lower body, and accordingly, the drive transmission system is correspondingly arranged to the upper body. It must be divided into a main body and a lower body,
As a result, it becomes difficult to accurately fit the drive transmission systems divided into the two main bodies.

Particularly in the case of a photoconductor drum, the photoconductor drum must be rotated in synchronism with the scanning speed of the optical scanning means for forming a latent image on the drum and the timing of inserting the recording paper of the registration means, respectively, in synchronization with each other. There is uneven pitch in the latent image formed on the sheet, and the transfer position between the recording sheet and the toner image is deviated, which is extremely problematic in image formation.

On the other hand, since the photosensitive drum bearing the toner is generally disposed on the upper main body side, the toner scattering occurs due to the impact caused by the difference between the opening and closing operations of the upper main body, and the above-mentioned optical scanning means and other optical systems. There is also a problem that the image becomes unclear due to contamination of the.

In order to eliminate such drawbacks, for example, as shown in JP-A-61-279872, the photosensitive drum and process means disposed around the photosensitive drum may be unitized,
Only the lightweight unit such as the unitized process unit and other static elimination lamps is attached to the upper main body side to reduce the size and weight of the upper main body side, and the process unit is accurately attached to the upper main body side by using the guide means. The drive transmission system is attached to the lower main body side so as to connect to the drive receiving portion arranged on the upper main body side to operate the process unit. Since the process unit is accurately positioned on the upper main body side without being divided into the main body, the drive receiving portion of the process unit and the drive transmission system on the lower main body side are opened by opening the upper main body. It is possible to accurately connect, and it is possible to prevent the above-mentioned pitch unevenness, image shift, and the like due to poor fitting accuracy of the drive transmission system.

[Problems to be solved by the invention] However, in the above device, the cover body formed on the lower main body side and the opening / closing cover on the upper main body side are in contact with each other. Due to the structure for positioning and supporting the main body, even if the upper main body is made lightweight, a large impact force will naturally be generated if the upper main body is roughly closed, and the drive transmission system and the drive receiving portion to be connected. The accuracy of fitting with the deviation occurs, and the toner is more likely to scatter from the exposed portion such as the peripheral surface of the inner photosensitive drum of the process unit.

Further, the connection between the rigid bodies may be out of precision due to long-term use, and also in the process unit, since it is positioned and supported only by the guide means on the upper body side, the position of the rigid body is also misaligned due to a large number of rotation operations of the upper body. Is likely to occur.

In view of the above-mentioned drawbacks of the prior art, the present invention has the advantage that even when the upper main body is divided and opened a large number of times, it is most sensitive to image irregularities such as pitch unevenness and image shift due to deviation of fitting accuracy of the drive transmission system. An object of the present invention is to provide an electrophotographic apparatus capable of performing stable positioning with stable fitting accuracy between a drive receiving portion of a body drum and a drive transmission system and always with high accuracy.

Further, another object of the present invention is to make it possible to softly close the upper main body by providing a cushioning effect even when the upper main body is roughly closed, and to provide an impact between the drive transmission system and the drive receiving portion. It is an object of the present invention to provide an electrophotographic apparatus in which the possibility of toner scattering and the like can be minimized without the need for mechanical fitting.

Another object of the present invention is to provide an electrophotographic apparatus capable of accurately setting a gap between a photosensitive drum provided on an upper main body side and a transfer device provided on a lower main body side, thereby preventing uneven transfer. The purpose is to do.

[Means for Solving the Problems] In order to achieve the technical problem, the present invention is a developing unit in which a developing roller is incorporated in an electrophotographic apparatus in which an upper body and a lower body can be divided and opened. And a process unit (hereinafter referred to as a drum unit) including a photoconductor drum having a drive receiving portion mounted concentrically with the drum shaft, are individually mounted on the upper main body side, and the developing unit is positioned on the upper main body side. At the point of attachment, the drum unit is swingably supported toward the lower main body side where the photosensitive drum and the developing roller are separated from each other.
A point at which an elastic member is connected between the drum unit and the upper main body, and a casing including a support for rotatably supporting the drum shaft is provided on the lower main body side, and a drive receiving unit for the photosensitive drum is provided on the casing. We propose an electrophotographic device whose essential constituent element is that the drive transmission system connected to the unit is rotatably supported.

That is, more specifically, the drum shaft support and the developing unit are positioned and mounted on the respective main body sides, and the drum unit located therebetween is supported so as to be swingable in the direction in which the photosensitive drum and the developing roller are separated from each other. The elastic member is connected between the drum unit and the upper main body to provide a cushioning effect.

In this case, it is preferable that a transfer device is arranged below a support member that supports the drum shaft, and that the support member sets the distance between the photosensitive drum and the transfer device.

[Operation] The present technical means provides the swing accuracy of the drum unit between the support member and the developing unit, which are positioned and fixed, so that the gap accuracy between the support member and the photosensitive drum shaft and the photosensitive drum and the developing roller can be improved. Positioning and mounting can be performed while maintaining high accuracy, and a soft landing is performed when the unit is mounted on the support side because an elastic member is connected between the swingably supported drum unit and the upper body to provide a cushioning effect. The feature of the present invention is that the drum unit is positioned while being pressed and held.

That is, by closing the upper main body to the lower main body side, a drum unit swingably connected to the upper main body side via an elastic member is provided between the elastic member provided on the upper main body side and the support provided on the lower main body side. By the cooperative action, in other words, the elastic force of the elastic member is urged toward the support body to reliably position it on the support body, so the positional accuracy of the drum unit is independent of the upper body side, It is determined by the position accuracy of the support body, and even when the upper body is opened and closed many times, it is possible to position extremely accurately and stably as long as the support body on the lower body side does not wear. Become.

At the same time, the drum unit can be swung even between the developing units that are positioned and fixed, so that the positioning and mounting between the two can be performed accurately.

Even when the drum unit is positioned through the drum shaft, it is not abutted impactally but is pressed and held in a soft landing manner by the cushioning effect of the elastic biasing force of the elastic member. The risk of body wear is extremely low.

Further, the soft landing positioning due to the cushioning effect of the elastic biasing force of the elastic member naturally reduces the impact force when the upper body is closed, and the toner is scattered by the impact and rattling of various members. Is unlikely to occur.

Moreover, since the elastic member is urged by the elastic force in the direction of opening the upper main body, the opening operation thereof becomes easy.

Further, the drive transmission system formed on the lower main body side and a casing forming the support body are integrally supported by a shaft, and the drive receiving portion of the photosensitive drum connected to the drive transmission system is directly supported on the support body. Since it is concentrically attached to the drum shaft to be supported, the fitting accuracy of the drive transmission system and the drive receiving portion can be equal to or higher than the positioning accuracy of the process unit. Therefore, even when the upper body is divided and opened many times,
The fitting accuracy between the drive receiving portion of the photoconductor drum and the drive transmission system can be stably and always positioned with high accuracy, and as a result, the fitting accuracy of the drive transmission system of the photoconductor drum is incorrect. It is possible to completely prevent image distortion such as pitch unevenness and image shift.

Further, according to the present invention, a transfer device is arranged below the support, and the support is used to set the distance between the photoconductor drum and the transfer device. It is possible to accurately set the interval between the transfer devices provided on the side of the lower main body and the transfer unit, and it is possible to prevent uneven transfer due to the deviation of the interval setting.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be exemplarily described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but merely illustrative examples. Nothing more than.

FIG. 1 shows a laser printer according to an embodiment of the present invention, in which an upper main body A and a lower main body B which can be divided and opened substantially along a recording paper conveyance path around a rotation fulcrum C provided on a side wall of a paper feed side.
Consists of.

The upper body A is composed of an upper frame body 1 that supports various members described below in a fixed or detachable manner, and an upper cover body 2 that substantially conceals the space above the frame body 1, and the upper cover body 2 is A discharge tray formed by forming a concave arc-shaped upper discharge guide surface 2a forming a part of a discharge unit 28, which will be described later, on the discharge-side side wall surface and forming a concave slope on the outlet side of the discharge guide surface 28. The part 2b is provided.

Further, the frame body 1 has an optical scanning means 37 on the upper surface of the paper feed side.
However, a developing unit 4 which is detachably fixed at a predetermined position by a pair of guide grooves 1a and 1b formed in the frame body 1 in the central portion on the lower surface side, and a developing roller incorporated in the unit 4 A process unit 3 swingably supported by the frame body 1 is detachably attached to the side facing the developing roller 4a, and the photosensitive drum 5 is attached to the process unit 3 on the side facing the developing roller 4a. A part of the electrophotographic process means such as the cleaning member 6 and the charger 7 is housed on the peripheral surface. As shown in FIG. 2, a gear 11 as a drive receiving portion having a diameter slightly larger than the diameter of the photosensitive drum 5 is attached to both ends of the photosensitive drum 5 concentrically with the drum shaft 5a. There is. Incidentally, 19 shown in FIG.
Is a static elimination lamp attached to the frame body 1 on the upper surface side of the process unit 3.

Next, the supporting structure of the process unit 3 and the frame body 1 will be described in detail.
On the side of the upper surface of the process unit 3 that is close to the photoconductor drum 5, a cylindrical portion 12 is provided as a recess, and a coil spring 13 is housed in the cylindrical portion 12, and the coil spring 13 directs the process unit 3 toward the lower main body B. Apply elastic force.

A spherical projection 14 is provided on the rear wall surface of the process unit 3 opposite to the photoconductor drum 5, and the projection 14 is fitted into a spherical recess 15 provided on the facing frame body 1 side.

As a result, the process unit 3 is moved in the direction in which the photosensitive drum 5 and the developing roller 4a are separated from the frame body 1 while the elastic force is urged by the coil spring 13 toward the lower main body B with the spherical projection 14 as a fulcrum. It will be swingably supported.

On the other hand, on the lower main body B side, along the recording paper conveyance path, the recording paper storage stand 21, the paper feed roller 22, and the friction plate 23a on the free end side of the tip end are provided.
A paper feed separator 23 that presses the friction plate 23a onto the peripheral surface of the paper feed roller 22 by a leaf spring; a registration roller 24 that guides the recording paper fed by the separator 23 to a transfer position at a predetermined timing; A transfer device 25 arranged to face the lower peripheral surface of the body drum 5, a conveyance roller 29, a conveyance guide 26 formed on the upper surface side of the lower frame body 1, a fixing device 27 for thermally fixing an unfixed toner image, and the fixing device 27. The paper discharge unit 28 provided on the downstream side is incorporated.

As a result, the paper feed roller 22 and the registration roller 22 which operate by receiving the rotation of the drive transmission system 31 connected to the motor drive source M
24, the transport roller 29, the fixing roller 27a, and the drive roller 28b attached to the guide member 28a of the paper discharge unit 28 are located on the lower main body side. Even if it is arranged only on the side, no problem will occur, and the rotational force can be smoothly applied without causing a gear meshing error or a meshing failure.

The drive source M and the drive transmission system 30 are, as shown in FIG. 2, various electrophotographs arranged on both sides in the lateral direction of the frame body 1 constituting the lower main body B, in other words, on the recording paper conveyance path. The process means is rotatably supported on the inner wall surface side of one casing 32 formed upright on both shaft end sides and is capable of imparting a rotational force to the various process means connected to the drive transmission system 30. Is configured. A supporting body 31 protruding in a rectangular shape is provided at a portion of the casings 32, 33 located on both sides in the axial direction corresponding to the photosensitive drum 5 axis, and its upper surface can be fitted with the photosensitive drum 5 axis U. The groove 31a is recessed.

According to such an embodiment, when the engagement member 9 provided on the end side of the frame body 1 is disengaged and the upper main body A is divided and opened, the process unit 3 supported by the frame body 1 has the spherical projections. With the fulcrum 14 as a fulcrum, the coil body 13 swings in a direction in which the photosensitive drum 5 and the developing roller 4a are separated from each other with the elastic force being urged toward the lower body B side. Therefore, even if the developing unit 4 and the process unit 3 are detached in this state, various accidents that occur during the detaching operation can be prevented without rubbing or contacting between the developing roller 4a and the photosensitive drum 5.

On the other hand, by rotating the upper main body A to the lower main body B side, the U-groove-shaped support 31 in which the drum shaft 5a is provided on the lower main body B side 31
, And by further rotating in the state of closing the upper body A in that state, the elastic force of the coil spring 15 is urged toward the support body 31 side, and the process unit 3 is securely supported by the support body 31. It can be positioned on the U groove 31a.

The gear 11 provided concentrically with the axis of the photosensitive drum 5 by the positioning support forms the casings 32, 33 forming the support.
A drive transmission system 30 which is rotatably supported on the photosensitive drum 5 is accurately fitted to the photosensitive drum 5 so that a rotational force can be smoothly applied.

Further, by accurately positioning the shaft of the photosensitive drum 5, the developing roller fixed on the upper frame 1 side also abuts on the peripheral surface of the photosensitive drum 5 through the sleeve with an appropriate pressure contact force, and It can be rotated in synchronization with the rotation of the drum 5.

[Advantage of the Invention] As described above, according to the present invention, the support, the photosensitive drum shaft, and the photosensitive drum are provided by disposing the swingable drum unit between the positionally fixed support and the developing unit. And the developing roller can be positioned and mounted while maintaining a high precision, and an elastic member is connected between the swingably supported drum unit and the upper body to provide a cushioning effect. Since it positions the drum unit while pressing and holding it like a soft landing when it is mounted on, the upper body is closed to the lower body side, so that the upper body side is swingably connected via an elastic member. The drum unit is made to cooperate with the elastic member provided on the upper body side and the support body provided on the lower body side, in other words, the elastic member Since the elastic force is urged to the support side to surely position it on the support, the positional accuracy of the drum unit is determined by the positional accuracy of the support on the lower body side, regardless of the upper body side. Even when the main body is opened and closed many times, the lower main body side can be positioned extremely accurately and stably as long as the support body does not wear.

At the same time, the drum unit can be swung even between the developing units that are positioned and fixed, so that the positioning and mounting between the two can be performed accurately.

Even when the drum unit is positioned through the drum shaft, it is not abutted impactally but is pressed and held in a soft landing manner by the cushioning effect of the elastic biasing force of the elastic member. The risk of body wear is extremely low.

Even when the upper main body is divided and opened many times, the drive receiving portion and the drive transmission system of the photoconductor drum, which are most affected by image irregularity such as pitch unevenness and image shift due to incorrect fitting accuracy of the drive transmission system It is possible to perform stable positioning with stable fitting accuracy between the two.

Further, according to the present invention, even when the upper body is roughly closed, the upper body can be softly closed because the elastic member has a cushioning effect at the time of closing the toner. It is possible to minimize the risk of scattering.

Further, according to the preferred embodiment of the present invention, it is possible to accurately set the gap between the photoconductor drum provided on the upper body side and the transfer device provided on the lower body side, thereby preventing transfer unevenness.

Has various remarkable effects.

[Brief description of drawings]

1 and 2 show a laser printer according to each embodiment of the present invention, FIG. 1 is an overall sectional view showing a divided and closed state of an upper body A and a lower body B, and FIG. 2 is a process unit. It is a principal part perspective view which shows the positioning support part. A: upper body, B: lower body, 5a: drum shaft 11: drive receiving portion (gear), 5: photoconductor drum 3: process unit, 13: elastic member 31: support body, 32, 33: housing, 30 : Drive transmission system, 25: Transfer device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-62-170993 (JP, A) JP-A-62-192771 (JP, A) JP-A-60-8856 (JP, A) JP-A-62-1 115470 (JP, A)

Claims (2)

[Scope of utility model registration request] 1. An electrophotographic apparatus having an upper main body and a lower main body which can be opened separately. A developing unit having a developing roller incorporated therein and a photosensitive drum having a drive receiving portion concentric with a drum shaft. The process unit including the above is individually attached to the upper main body side, and the developing unit is positioned and mounted on the upper main body side, while the process unit is swingable toward the lower main body side where the photosensitive drum and the developing roller are separated from each other. A housing including a support body that supports the drum unit and rotatably supports the drum shaft is provided on the lower body side while supporting the process unit and the upper body, and the photosensitive drum is provided on the housing. An electrophotographic apparatus characterized in that a drive transmission system connected to a drive receiving portion of the vehicle is rotatably supported. 2. An electrophotographic apparatus according to claim 1, wherein a transfer device is arranged below the support, and the space between the photosensitive drum and the transfer device is set by the support.