JPH0723796Y2 - Electrophotographic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to an electrophotographic apparatus for forming an image by an electrophotographic process such as a copying machine, a printer, a facsimile, and more specifically, an electrophotographic process means. The present invention relates to an electrophotographic apparatus in which one or more process units forming at least a part are detachably attached to an apparatus main body.

“Conventional Technology” Conventionally, an electrostatic latent image formed on a photosensitive drum using a laser beam modulated according to input information or reflected light corresponding to an original image can be formed using a developing device. Electrophotographic devices such as copiers and printers, which transfer images onto recording paper and then form a predetermined image after visualizing, are well known, and in this type of device, assembling at the time of manufacturing, maintenance and consumers are easy. In order to speed up and facilitate the parts replacement at the level, a part of the electrophotographic process means such as a photoconductor drum, an optical system, a developing device, a transfer device, a cleaning member, a static eliminator, a charger and a fixing device, or All of them are unitized, and the unit is configured to be detachable from the main body of the apparatus. Further, from the viewpoint of facilitating toner replacement, durability and cost, a member including a photosensitive drum and a member including a developing device are respectively provided. Uni separately There is an apparatus configured to be detachable (hereinafter, one is referred to as a drum unit and the other is referred to as a developing unit) and can be independently detached from the apparatus main body.

However, due to the construction of the electrophotographic process, the photosensitive drum and the developing roller incorporated in the developing device are arranged in contact with each other or at positions extremely close to each other, so that the drum unit and the developing unit can be independently removed. Then,
When detaching one of the units from the main body of the apparatus, the photosensitive drum is erroneously rubbed against the surface of the developing roller,
It may damage the surface of the photoconductor drum.

Therefore, in such an apparatus, it is often the case that the developing roller is once separated from the photosensitive drum and then any one of the units is removed from the apparatus main body side.

In such a separating device, for example, in a device in which the device body side is divided into an upper body and a lower body, both the units are attached to the upper body side, and at least one of the units is provided with one rotation fulcrum. It is configured so as to be swingable in the direction in which the photosensitive drum and the developing roller are separated from each other around the center, and thereby the unit is separated by opening the upper main body so that the unit is separated from the photosensitive drum and the developing roller. The rotation fulcrum is provided as a means for automatically swinging and separating to a position where there is no risk of contact, allowing easy unit replacement without damaging the photosensitive drum, and as a means for swingably supporting such a unit. A method of cantilever supporting one supporting shaft extending on the axis of the device and inserting the supporting shaft from its free end side, and a pair of supporting portions composed of the supporting shaft or the shaft hole. Provided in the body both ends, the support portions of the unit by using longitudinally opposite ends of the (rotation axial direction of the fulcrum) can be divided into a method for supporting two points of.

[Problems to be Solved by the Invention] However, the former configuration has an advantage that it is easy to attach and detach using the support shaft as a guide because one support shaft extends on the axis of the rotation support point. Since the support shaft is cantilevered, the support shaft itself oscillates, making it difficult to obtain positional accuracy, and as a result, it is difficult to obtain accurate positional accuracy between the developing roller and the photosensitive drum.

On the contrary, in the latter two-point support method, the stability of the position accuracy can be secured, but since the support parts need to be provided in a protruding or concave shape at both ends in the axial direction of the apparatus main body, the support parts are Only by guiding the unit in the axial direction as an obstacle, it is impossible to support the unit to the supporting portion. Therefore, generally, the unit is axially displaced from the position deviated from the axial line in the main body of the apparatus. Or move the unit in a direction orthogonal to the axis to pivotally support the support section,
Alternatively, there is no choice but to adopt a configuration in which the unit is mounted obliquely with respect to the axis, which complicates the configuration.

In view of the drawbacks of the prior art, the present invention adopts the advantages of the one-point supporting method and the two-point supporting method, and achieves both stability of positional accuracy and facilitation of guidance. The purpose is to provide.

[Means for Solving Problems] The present invention relates to an electrophotographic apparatus in which a process unit is mounted on an apparatus main body so as to be swingably supported in a direction orthogonal to a unit attaching / detaching direction. The point is provided with an oscillating frame body supported by the main body of the apparatus so as to be swingable in a direction orthogonal to the unit attaching / detaching direction around one rotation fulcrum, and one side of the process unit is attached to the oscillating frame body. Point that is configured to be positionable and fixable Point on the front side of the frame that is located on the rotation fulcrum axis and that has a support part consisting of a support shaft or shaft hole on the side of the main body of the device. We propose an electrophotographic device that has an indispensable constituent point that it is rotatably supported.

The unit generally includes all process units that are detachably attached to the main body of the apparatus, but especially for a developing unit or a drum unit that needs to be detached in the drum axial direction after being separated in the direction orthogonal to the photosensitive drum. It is practically advantageous to apply.

[Operation] According to the technical means, the frame body shares the rotation fulcrum with the support portion, so that the positioning guide portion between the process unit and the frame body is necessarily provided at a position deviated from the axis. For that reason, there is only one support portion located on the rotation fulcrum axis line on the side of the apparatus main body, and therefore, substantially like one-point support, the guide rail is parallel to the axis line. By arranging, the process unit can be automatically guided and fitted to the supporting portion side only by guiding the process unit along the guide rail, and with the fitting, rotation with the supporting portion can be performed. The process unit can be fixed in position on the frame side that has a common fulcrum.

As a result, one side of the process unit is rotatably supported on the rotation fulcrum via the swing frame body, and the other side of the process unit is rotatably supported on the support portion located on the rotation fulcrum axis of the frame body. Since it is pivotally supported, and the so-called substantially two-point support structure is provided, it is possible to easily secure the stability of position accuracy.

Further, when the process unit is configured as a developing unit, the developing unit can be swung in a direction in which the developing unit separates from and comes in contact with the photosensitive drum about the rotation fulcrum, so that the drum is damaged when the developing unit is attached and detached. In addition, the fear can be completely prevented, and particularly in the case of the main body split type device, the unit is automatically oscillated and separated to a position where there is no fear of contact between the photosensitive drum and the developing roller by opening the split main body. Things are possible.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be 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 to FIG. 3 are main part configuration diagrams of a laser printer according to an embodiment of the present invention, in a plane orthogonal to a photosensitive drum shaft 11a about a rotation fulcrum C provided on a side wall of a sheet feeding side. It is composed of an upper main body A and a lower main body B which can be divided and opened along.

The lower main body B is provided with a sheet feeding roller (not shown), a registration roller, and a transfer device and a fixing device (not shown in the figure except the transfer device 12), which face the lower peripheral surface of the photosensitive drum 11 along the recording paper conveyance path. ) Are arranged, and portions corresponding to the photoconductor drum shafts 11a located at both ends of the transfer unit 12 are provided in a rectangular shape so as to form a support 14 and the upper surface thereof is provided on the photoconductor drum shaft 11a.
A U groove 14a is provided so as to be fittable with a.

On the other hand, the upper main body A is attached / detached along the drum shaft 11a direction (direction orthogonal to the split opening direction) via the guide grooves 31a, 31b and the guide rails 32a, 32b integrally formed with the upper main body A. The developing unit 2 and the drum unit 1, which are freely mounted, are arranged to face each other.

As shown in FIG. 1, the developing unit 2 includes a photosensitive drum 11
The developing roller 21 disposed on the side facing the developing roller 21 is rotatably supported and accommodates a two-component developer at a predetermined mixing ratio. The developing container 22 is replaceably mounted above the developing container 22 via a toner replenishing mechanism 23. As shown in FIGS. 3 and 1, the developing container 22 is provided with rail guides 20a, 20b on both sides in the longitudinal direction, and the front end face of the developing container 22 is in a plane orthogonal to the drum shaft 11a. An arm portion 25 that extends substantially horizontally to a position substantially above the photosensitive drum 11 is provided along with, and a support shaft hole 25a is provided at the tip of the arm portion 25 toward the drum shaft 11a direction. On the rear end surface side of the developing unit 2, a pair of guide pins 27a, 27b protruding on the side of the frame body 4 described later, a connector 26 for supplying power to a toner sensor (not shown), and various bearings are attached. ing.

On the other hand, as shown in FIGS. 3 and 4, a tongue piece 33 is hung on the front end side of the main body ceiling portion substantially above the photosensitive drum 11 in the main body of the apparatus constituting the upper body A. Support shaft 25a
While piercing the support shaft 33a into which is rotatably fitted,
The shaft hole on the upper main body housing A1 that stands upright in the axial direction
The frame body 4 is swingably supported about a fulcrum C provided at a position corresponding to 33a.

The frame body 4 is pivotally supported about the fulcrum C along the split open surface, and is widened from the pivotal support position to the developing container 22 side to form a guide pin on the developing container 22 side.
A pair of guide portions 41a, 41b at positions corresponding to 27a, 27b, a position corresponding to the drive receiving portions 23a 29a, a drive conduction system 43 connected to the DC motor 42, and a socket 44 at a position corresponding to the connector 26. Wear each one.

The pair of guides is provided with a guide pin 27 provided on the developer container 22 side.
A circular hole 41a and a square kerf 41 formed at positions corresponding to a and 27b.
b, the cut groove 41b is opened in the X-axis direction, and the guide pin 27a,
It is configured to be able to absorb the mounting error between 27b.

On the other hand, the drum unit 1 includes a photosensitive drum 11 which is rotatably supported on the right side in the figure, a cleaning member (not shown) and a charger, which are housed in a position facing the drum 11, and both ends of the drum 11. On the drum shaft 11a located on the side, a spacing roller 19 having a diameter slightly larger than the diameter of the photosensitive drum 11 and a drum gear concentric with the spacing roller 19 are provided.
18 is attached and the closing operation of the upper body A causes the drum gear to move.
18 and a drive transmission system (not shown) on the lower body B side.

The drum unit 1 includes a pair of rail guides 17a,
While being guided by the guide rails 32a, 32b on the upper body A side via 17b, it is swingably supported in the direction of the arrow, and a cylindrical recess 16 is provided in the upper body A located above the photosensitive drum 11. Then, the coil spring 15 housed in the recess 12 is configured to be able to urge the elastic force toward the drum unit 1 toward the lower body B side.

Next, the mounting operation of each unit based on such an embodiment will be described. First, in the developing unit 2 which is a main part of the present invention, a pair of guide grooves 3 on the side of the upper main body A via the rail guides 20a and 20b.
If the guide shafts 1a and 31b are inserted into the back side as they are, the support shaft 25a provided on the arm portion 25 extending from the developing container 22 is inserted into the shaft hole 33a on the upper main body A side at the same time immediately before the mounting is completed, and at the same time the unit The guide pins 27a, 27b projecting from the rear end face are accurately fitted to the guide portions 41a, 41b of the rocking frame body 4, whereby the unit 2 is positioned and fixed to the frame body 4, and the guide pins 27a are formed. , 27b as guides, the socket 44 on the frame body 4 side and the drive conduction system 43 are connected to the connector 26 and the drive receiving portions 23a 29a on the developing unit 2 side.

As a result, the developing unit 2 is swingably supported on the upper main body A side about the support shaft 33a, but its swing range is one of the upper main body A side via the rail guides 20a and 20b. Since it is regulated by the guide groove, it is always separated from the photosensitive drum 11 on the drum unit 1 side, and there is no possibility of contact with each other.

Next, the drum unit 1 is mounted along the guide rails 32a and 32b so that the photosensitive drum 11 and the developing roller 21 are swingably supported with the supporting portion of the one guide rail as a fulcrum C. The closing operation of the upper main body A causes the drum unit 1 to rotate after the drum shaft 11a is pivotally supported in the U groove 14a on the lower main body B side and while the elastic force of the coil spring 13 is applied from above the drum unit 1. Is accurately positioned and fixed at a predetermined position, and at the same time, the developing unit 2 is also accurately positioned on the peripheral surface of the spacing roller 19 via the developing roller 21 by its own weight.

Next, when the upper main body is divided and opened, the developing unit 2 swings around the support shaft 25a, and the drum unit 1 swings in a direction in which the photosensitive drum 11 and the developing roller 21 are separated from each other with one guide rail as the fulcrum C. It is possible to split and open while moving, and as a result, it is possible to pull out each unit 1 and 2 without contacting each other.

[Advantages of the Invention] As described above, according to the present invention, the swing frame body that is swingably supported by the main body of the apparatus and the support portion that has a common rotation fulcrum with the frame body are effectively used. As in the case of substantially one-point support, one process unit can be swingably supported and fixed to the apparatus main body side, and after mounting, a so-called substantially two-point support is provided via the swing frame body. Because of the structure, it is possible to easily secure the stability of the position accuracy.

Further, when the process unit is configured as a developing unit, it is possible to completely prevent the risk of drum damage at the time of attaching / detaching the unit, and particularly in the case of a main body split type device, the unit is automatically opened by the split opening of the upper main body. In addition, it is possible to swing and separate the photosensitive drum and the developing roller to a position where there is no risk of contact.

It has various remarkable effects.

[Brief description of drawings]

FIGS. 1 and 2 are configuration diagrams of a main part of a laser printer according to an embodiment of the present invention, and FIGS. 1 and 2 show an arrangement configuration when the upper body is closed and when the division is opened. FIG. 3 is a perspective view of the developing unit and the frame body, and FIG. 4 is a plan view showing the assembled state.

Claims (2)

[Scope of utility model registration request] 1. An electrophotographic apparatus in which one or a plurality of process units constituting at least a part of an electrophotographic process means are detachably attached to an apparatus main body, and a unit attaching / detaching direction is centered around one rotation fulcrum. A swing frame body supported by the apparatus main body so as to be swingable in the orthogonal direction is provided, and one side of the process unit is configured to be positionably fixed to the swing frame body, and the other side of the process unit. The electrophotographic apparatus is configured so that it can be rotatably supported by a support portion provided on the apparatus main body side located on the rotation fulcrum axis line on the front surface side of the frame body. 2. An electrophotographic apparatus, wherein positioning between the process unit and the frame body is performed by a guide portion provided at a position deviated from the rotation fulcrum axis line.