JPH01261663A - Image forming device - Google Patents

Abstract

PURPOSE:To easily, surely and quickly attach and detach a development device by providing a lever with a plate spring engaged with a part of the development device to be freely turned on the upper part of the development device. CONSTITUTION:When a top frame 11 is closed against a bottom frame 12, a link 27 shifts in the direction shown by an arrow D, and since the lever 23 with the plate spring 22 is pulled and turned by such shift, the development device 15 engaged with the plate spring 22 shifts to the side of a photosensitive drum 14 and the device 15 is opposingly positioned with a certain interval, and it is automatically locked by the spring force of the plate spring 22. Contrary, when the top frame 11 is opened against the bottom frame 12, the link 27 shifts in the push back direction, and the lever 23 with the plate spring 23 is also pushed back, and the development device 15 engaged with the plate spring 22 is easily separated from the photosensitive drum 14 side. Thus, the development device 15 is easily and quickly removed and installed from the top frame 11 without damaging the plane of the photosensitive drum 14.

Description

[Detailed Description of the Invention] [Summary] This invention relates to an attachment/detachment mechanism for a developing device that is arranged facing a photosensitive drum with a predetermined gap in an electrophotographic image forming apparatus, and that automatically attaches and detaches each developing device as the upper frame opens and closes. The purpose of this invention is to make it possible to lock the developing device away from the photosensitive drum or close to it with a predetermined gap, thereby facilitating the attachment and detachment of the developing device. On the other hand, in a device configuration in which an upper frame including a photosensitive drum and a developing device disposed opposite to the drum with a predetermined gap can be opened and closed in the vertical direction by a hinge portion, the developing device can be moved toward the photosensitive drum by a supporting portion. A lever with a leaf spring is rotatably provided above the developing device and engages with a part of the developing device, and the lever with the leaf spring is attached above the lower frame portion near the hinge portion. The links provided in the frame are connected via a support shaft provided in the frame, and when the upper frame is closed, the leaf spring-equipped lever is pulled by the link and the developing device is moved to the photosensitive drum accordingly. The developing device is fixed at a predetermined gap position, and when the frame is opened, the developing device is moved away from the photosensitive drum by pushing back the link and rotating the leaf-spring lever.

[Industrial application field]

The present invention relates to improvements in electrophotographic image forming apparatuses, and more particularly to a mechanism for easily attaching and detaching a developing device, which is disposed facing a photosensitive drum with a predetermined gap, in the image forming apparatus.

In recent years, electrophotographic image forming apparatuses such as laser printers and copying machines have been required to have a structure that facilitates paper jam removal in the paper travel path and maintenance of developing devices, photosensitive drums, etc. Accordingly, in these devices, a lower frame having a paper cassette storage section, etc., and an upper frame having a photosensitive drum, a developing device, etc., are divided into two by a main paper running path that communicates with each of these paper running paths. This problem is solved by configuring the upper frame to be openable and closable with respect to the so-called lower frame, and furthermore, it is possible to easily attach and detach the developing device, which is disposed opposite to the photosensitive drum with a predetermined gap, during maintenance. Equipment configuration is required.

[Conventional technology]

A conventional electrophotographic image forming apparatus in which an upper frame can be opened and closed with respect to a lower frame 1/-, as shown in the conceptual schematic diagram of FIG. A developing device 15 is disposed facing the developing device with a predetermined gap therebetween.
An upper frame 11 including a fixing device 16 and the like is configured to be openable and closable via a hinge portion 13 with respect to a lower frame 12 having a paper cassette accommodating portion 17, a paper running path 18, and the like.

[Problem to be solved by the invention]

By the way, in the conventional electrophotographic image forming apparatus as described above, when the developing device 15 disposed opposite to the photosensitive drum 14 is attached or detached, for example, when the developing device 15 is removed, the process shown in FIG. 4 is performed. First, face the upper and lower frames 12
The upper frame 11 is inserted through the hinge part 13 in the direction of arrow A.
After opening the developing device 15 upward and unlocking the locking portion 19 of the developing device 15, the developing device 15 is temporarily moved away from the opposing photosensitive drum 14 in the direction of arrow B and removed. Furthermore, when installing the developing device 15, after opening the upper frame 11, the developing device 15 is temporarily attached to a position spaced apart from the photosensitive drum 14, and then, the developing device 15 is mounted so as to face the photosensitive drum 14 with a predetermined gap. Since the developing unit 15 is positioned and locked and operated with the upper frame 11 closed, the operation of attaching and detaching the developing unit 15 must be performed in 2 to 3 operations, which is complicated and makes it difficult for the operator to save money. The drawback was that it was difficult to put on and take off.

In addition, with such a detachable structure, it is easy to forget to lock the developing device 15 and close the upper frame 11 (this poses a problem of causing malfunction of the device).

In view of the above-mentioned conventional problems, the present invention has been designed to automatically move the developing device away from the position facing the photosensitive drum and to automatically lock the developing device in the facing position when the upper frame is opened and closed. It is an object of the present invention to provide a new electrophotographic image forming apparatus in which the developing unit can be easily and quickly attached and detached.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention connects a lower frame having a paper cassette accommodating section and a paper running path to an upper frame provided with a photosensitive drum and a developing device disposed facing the drum with a predetermined gap, by means of a hinge section. In the apparatus configuration that can be opened and closed in the vertical direction, the developing device is disposed so as to be movable toward the photosensitive drum by a supporting portion, and a lever with a temporary spring that engages with a part of the developing device is rotated above the developing device. The lever is freely provided and has a structure in which a lever with a temporary cough spring is connected to a link disposed in the upper frame from a lower frame portion near the hinge portion through a support shaft.

[For production]

In the electrophotographic image forming apparatus of the present invention, when the upper frame is closed, the leaf spring-equipped lever is pulled by the link, and the developing unit is accordingly moved toward the photosensitive drum and automatically moves to a predetermined gap position. It is fixed in the locked state.

Further, when the supranuclear frame is opened, the developing device is automatically unlocked by rotating the leaf-spring lever by pushing back the link, and is easily separated from the photosensitive drum.

Therefore, the operation of attaching and detaching the developing device is easier, more reliable, and
And it can be done quickly. As a result, malfunctions of the apparatus due to forgetting to lock the developing device, etc., are eliminated.

〔Example〕

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

FIG. 1 is a schematic side view of essential parts conceptually showing an embodiment of an electrophotographic image forming apparatus according to the present invention. Note that parts having the same functions as those in FIG. 3 are given the same reference numerals.

In the figure, in this embodiment, the developing device 15 is connected to the engaging support portion 21.
The photosensitive drum 14 is movably arranged as shown by an arrow C with respect to the photosensitive drum 14. Further, a plate spring 22 is provided near the rear side of the developing device 15 and engages with a part of the developing device 15.
A lever 23 with an attached lever 23 is rotatably provided on a first support shaft 24 .

Furthermore, a portion of the lever 23 with the leaf spring 22 is connected via a third support shaft 26 provided in the upper frame 11 than the second support shaft 25 of the lower frame 12 near the hinge portion 13, as shown in the figure. The installed link 27 is connected.

When the upper frame 11 is closed with respect to the lower frame 12 as shown in FIG. The developing device 15 engaged with the leaf spring 22 moves toward the photosensitive drum 14, and is placed facing the photosensitive drum 14 with a predetermined gap therebetween, and is automatically locked by the spring force of the leaf spring 22. This eliminates the conventional problem of forgetting to lock.

On the other hand, when the upper frame 11 is opened with respect to the lower frame 12, the link 27 moves in the push-back direction shown by arrow E. At this time, the lever 23 with the leaf spring 22 is also pushed back, and the developing device 15 engaged with the leaf spring 22 is easily separated from the photosensitive drum 14 side.

Therefore, the developing device 15 can be easily and quickly removed from and attached to the upper frame 11 without damaging the surface of the photosensitive drum 14.

〔Effect of the invention〕

As is clear from the above description, according to the electrophotographic image forming apparatus according to the present invention, the developing device is automatically separated from the photosensitive drum or attached to the photosensitive drum simply by opening and closing the upper frame relative to the lower frame. The developing device can be disposed facing and locked against the upper frame, and the developing device can be easily and quickly attached to and detached from the upper frame.

Therefore, malfunctions of the apparatus caused by forgetting to lock the developing device are eliminated, and maintenance of the developing device and the photosensitive drum becomes easy, which provides excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of essential parts conceptually showing an embodiment of an electrophotographic image forming apparatus according to the present invention, and FIG. 2 is a schematic side view of a main part of an electrophotographic image forming apparatus according to the present invention. FIG. 3 is a schematic side view of the main parts to explain the operation of the conventional electrophotographic image forming apparatus. FIG. 4 is a schematic side view of the main parts of the conventional electrophotographic image forming apparatus. FIG. 2 is a schematic side view of the main part for explaining the problem. 1 and 2, ]l is an upper frame, 12 is a lower frame, 13 is a hinge, 14 is a photosensitive drum, 15 is a developing device, 16 is a fixing device, 1
7 is a paper cassette storage section, 18 is a paper travel path, 21 is a retaining support section, 22 is a leaf spring, 23 is a lever, 24 is a first support shaft, 25 is a second support shaft, 26 is a third support shaft, 27 each indicate a link. Figure 1 Figure 2

Claims (1)

[Claims] Paper cassette storage section (17) and paper travel path (18)
The lower frame (12) has a photosensitive drum (14).
) and a developing device (15) disposed opposite to the drum (14) with a predetermined gap. 15) is disposed so as to be movable toward the photosensitive drum (14) by means of an engagement support portion (21), and is connected to the developing device (15).
A lever (23) with a leaf spring (22) that engages with a part of the developing device (15) is rotatably provided above the developing device (15);
The hinge portion (
13) The upper frame (
A link (27) provided in the upper frame (11) is connected via a support shaft (26) provided in the leaf spring (2).
2) is pulled by the link (27), and the developing device (15) is moved to the photosensitive drum (14).
the upper frame (1) and fix it at a predetermined gap position.
1) When opened, the developing device (15) is separated from the photosensitive drum (14) by rotating the lever (23) with the leaf spring (22) by pushing back the link (27). Features of the image forming device.