JPS6323177A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To intercept laser beam with a simple constitution without requiring any excessive space, by providing an intercepting body, which respectively moves by means of its own weight to the outside and inside of the optical path of the laser beam when an upper frame is closed and opened, between a laser beam source and rotary mirror in a case. CONSTITUTION:An intercepting body 32 is fitted to an adaptor plate 37, whose one side is fixed to the inner wall of a case 29 closely to a laser beam source 31, in a state where the body 32 can rotate around a fulcrum 38. Weights 39 are installed to both sides of the lower section of the body 32 so that the body 32 can rotate by means of its own weight. When an upper frame 3 is turned upward, the intercepting body 32 is turned and, when the body 32 reaches a certain inclined state, intercepts laser beam 30 between the light source 31 and a rotary mirror 34. When, for example, the engagement of a clamp is released and the upper frame 3 is turned upward against a lower frame 2 with the purpose of exchanging a photosensitive drum 12, the intercepting body 32 is also turned as the upper frame 3 is turned. As a result, the body 32 enters into the optical path o the laser beam 30 and intercepts the laser beam 30.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention develops an electrostatic latent image formed on a photosensitive drum with a laser beam, and transfers the developed image to a medium such as paper. The present invention relates to an electrophotographic apparatus, and more particularly to a device for blocking laser light of an electrophotographic apparatus.

[Prior Art] In this type of electrophotographic apparatus, there are cases in which the upper frame is opened and the developing section is removed in order to replace, for example, a photosensitive drum constituting the developing section. At this time, normally when the upper frame is opened, a device is installed that detects the opening of the frame using a micro switch or the like and stops the emission of laser light, but as an additional safety device, a device is installed in the case containing the laser light source, etc. There are some devices in which the exit of the emitted laser beam is blocked by a transparent material.

That is, the laser beam is scanned by a rotating mirror, and the light is reflected by a reflecting mirror and enters the developing section. A diaphragm device in which a diaphragm is moved by the bias of a spring is provided at the case exit between the reflecting mirror and the developing section. When the developing section is removed from the upper frame, this closing body closes the exit of the laser beam by the bias of a spring. Then, when the developing section is reattached to the upper frame, a part of the developing section pushes against the slow-closing body against the force of the nonone, so the shielding body that was blocking the exit of the laser beam moves. The laser light enters the developing section.

[Problems to be Solved by the Invention] However, since the above-mentioned transducer device passes the laser beam after scanning, the transparator device itself becomes large. Furthermore, since a spring is used to move the transparent body, the structure is complicated and the operation is uncertain.

The present invention has been made in view of these points, and it is an object of the present invention to provide an electrophotographic apparatus that does not take up much space and can block laser light with a simple configuration.

[Means for solving the problem] An optical unit (T-mounted system) is an optical unit in which an upper frame and a lower frame are connected to each other so as to be openable and closable, and a laser light source that emits a laser beam, a rotating mirror, etc. are housed in a case of the upper frame. Additionally, a blocking body is provided between the laser light source and the rotating mirror in the case, which move by their own weights to the outside of the optical path of the laser beam when the upper frame is closed and into the optical path when opened.

[Function] By rotating the upper frame upward relative to the lower frame when replacing, for example, the photosensitive drum constituting the developing section, the upper frame is tilted, so that the blocking body moves into the laser beam path due to its own weight. to block the laser beam. Therefore, when the upper frame is rotated, even if the emission of laser light is not stopped due to a malfunction of a switch or the like, there is no risk of looking directly into the laser light.

[Embodiment] A first embodiment of the present invention will be described based on the drawings. In FIG. 1, 1 is a housing. This housing 1 has a lower frame 2 and an upper frame 3, and these lower frame 2 and upper frame 3 are rotatably connected around a support shaft 4 as a fulcrum. Further, clamps (not shown) are attached to the front portions of the lower frame 2 and the upper frame 3 so as to be releasably engaged with each other.

At the bottom of the lower frame 2, a cassette case 6 for storing a large number of sheets of paper 5t in a stacked state is removably attached from the front. have. Information board 7
A guide plate 9 that guides the paper 5 in opposition to the guide plate 9 is held by the lower frame 2.

The lower frame 2 also includes a paper feed roller 10 that pulls out the paper 5 in the cassette case 6, and feed rollers 13 and 14 that transport the paper 5 to the photosensitive drum 12 that constitutes the developing section 11.
, a transfer charger 15, and a feed roller 217 that guides the paper 5 that has passed through the transfer charger 15 to the fixing device r1t16. The fixing device 16 includes a pressure roller 218 held by the lower frame 2 and a heating drive roller 19.

Furthermore, the upper frame 3 includes a guide plate 20 that guides the paper 5 that has passed through the fixing device 16, feed rollers 22 and 23 that send the paper 51 to the paper receiver 21, an optical unit 24, an electrostatic charger 25, and a charger 25, which will be described later. An electric appliance 26, a motor 27, and a PC board 28 are provided.

The optical unit 24 attached to the upper frame 3
is a laser light source 31 that emits a laser beam 30 inside the case 29;
and a blocker 32 that blocks the optical path of the laser beam 30,
a rotating mirror 34 rotated by a scanner motor 33 to scan the laser beam 3o onto the photosensitive drum 11;
An imaging lens 35 is arranged so that the laser beam 30 reflected by the rotating mirror 34 is focused on the photosensitive drum 12, and the laser beam 3 emitted from the imaging lens 35t at this time.
It also holds a reflecting mirror 36 that bends the optical path of zero. The inside of the case 29 and the shield 32 are painted black to prevent leakage due to light reflection.

As shown in FIG. 2, the shield 32 is mounted close to the laser light source 31 on a mounting plate 37 with one side fixed inside the case 29 so as to be rotatable about a fulcrum 38t, and at the bottom there is a mounting plate 37 that can be rotated by its own weight. Heavy weights (39t) are provided on both sides so that it can be easily carried out. Then, as the upper frame 3 rotates upward, the blocking body 32 rotates and cuts off five degrees of laser light between the laser light source 31 and the rotating mirror 34 when the upper frame 3 is tilted. A stopper 40 is provided at the end of the mounting plate 37 on the side of the blocking body 32 so that the blocking body 32 remains within the optical path even if the upper frame 3 is tilted beyond a certain level.

In such a configuration, when, for example, the photosensitive drum 12 constituting the developing section 11 is replaced, the engagement of the flang (not shown) is disengaged and the upper frame 3 is rotated upward relative to the lower frame 2. Accordingly, the blocking body 32 also rotates due to its own weight, enters the optical path of the laser beam 30, and blocks the laser beam 30. However, in addition, upper frame 3
Even if the inclination increases, since the shield 32 is fixed by the stopper 40 provided on the mounting plate 32, the laser beam will always be cut off by 30 fCM above a certain inclination.

The embodiments described above are not limited to this,
For example, the following embodiments may also be considered.

A second embodiment will be described based on the drawings.

In the second embodiment, as shown in FIG. 3, the shield 32fc is disk-shaped, and a holder 41 is formed to hold the shield 32 at the top and bottom, rotate it, and stop the movement at both ends. It is installed between the light source 31 and the rotating mirror 34. In this case, the holding body 41 is installed with a slight inclination so that the blocking body 32 moves out of the optical path when the upper frame 3 is closed.

With this configuration, when the upper frame 3 is closed, the blocking body 32 is located outside the optical path, and when the upper frame 3 is opened, the blocking body 32 rolls due to the inclination of the holding body 41 and is fixed in a state blocking the optical path. are doing.

Furthermore, the blocking body 32 may be made into a rectangular shape instead of a disk shape, and may be moved by sliding.

[Effects of the Invention] As described above, this invention blocks the laser beam before it is scanned by the rotating mirror, so the structure of the device itself is smaller than that of the conventional one, and furthermore, it operates by the weight of the blocking body. It has the effect of performing reliable operation with a simple mechanism.

[Brief explanation of the drawing]

The figures show embodiments of the present invention. Fig. 1 is a vertical cross-sectional side view of the housing and optical unit of the first embodiment, and Fig. 2 is the inside of the optical unit of the first embodiment. FIG. 3 is a vertical sectional side view showing a part of the optical unit of the second embodiment in cross section. 2... Lower frame, 3... Upper frame, 4-4
Axis (fulcrum), 24 - Optical unit, 30 Laser light, 31 Laser light source, 32 Blocker, 34
...Rotating mirror.

Claims (1)

[Scope of Claims] An upper frame is connected to a lower frame so as to be openable and closable in the vertical direction around a fulcrum, and the upper frame is provided with an optical unit that includes a laser light source that emits laser light, a rotating mirror, etc. housed in a case. In the electrophotographic apparatus, a blocking body is supported within the case so as to be movable by its own weight in close proximity to the laser light source, and moves out of the optical path of the laser beam when the upper frame is closed and into the optical path when the upper frame is opened. An electrophotographic device characterized by being provided with.