JPH0596826U - Electrophotographic recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] Regarding the structure of the shutter of the laser scanning unit for forming an electrostatic latent image on an image carrier in an electrophotographic recording apparatus,
A shutter is opened only when an electrostatic latent image is formed to improve the dustproof effect on the laser scanning unit. In an electrophotographic recording apparatus equipped with a laser scanning unit that irradiates a laser beam on the surface of an image carrier to form an electrostatic latent image, it faces a laser beam emission port of a case housing the laser scanning unit. And a shutter control circuit for controlling the shutter to be opened only during recording for emitting the laser light.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of an optical system shutter for forming an electrostatic latent image on an image carrier in an electrophotographic recording apparatus.

Recently, with the expansion of office automation (OA), plain paper can be used and output devices with high printing quality have come to be used. For this reason, copying machines and facsimile machines using electrophotographic recording systems have been realized.However, in these machines, in order to ensure high printing quality, dust such as paper powder and toner on the inside of the machine, especially the optical system, is ensured. To prevent intrusion.

[0003]

[Prior Art]

 As shown in the schematic view of FIG. 4, the electrophotographic recording apparatus to which the present invention is applied includes an image carrier 1 such as a photosensitive drum having a photosensitive layer on the surface thereof which changes its conductivity in response to light, and an image carrier. The developing device 2 that adheres the toner to the drum surface by the potential difference from the surface of the image carrier 1, the charging device 3 that uniformly charges the surface of the image carrier 1, and the image carrier by irradiating and scanning the laser beam. The laser scanning unit 4 that changes the amount of charge on 1 to form an electrostatic latent image, the transfer unit 6 that transfers the toner image on the image carrier 1 onto the paper 5, and the toner image transferred onto the paper 5 A fixing unit 7 including a halogen lamp for heating and fixing is provided.

The laser scanning unit 4 is configured to include a laser light emitter 4a, a plurality of lenses 4b and 4c, and a plurality of reflecting mirrors 4d and 4e, and the whole is housed in a case 8 and integrated. There is.

The laser light emitted from the laser light emitter 4a is reflected by the reflecting mirror 4d through the lens 4b, further reflected by the reflecting mirror 4e through the lens 4c, and then the laser emission port 8a of the case 8 through the dustproof glass 4f. Is ejected toward the image carrier 1.

Further, the laser scanning unit 4 is provided with a shutter 9 facing the laser emission port 8a in order to prevent dust such as paper powder and toner from adhering to the dust-proof glass 4f in order to maintain high printing quality. There is.

The shutter 9 is a member having an L-shaped cross section, has a length that covers the entire width of the laser emission port 8a, and uses a shaft 10 provided in the L-shaped bent portion 9a as a fulcrum of rotation. The one surface 9b serves as a shutter to cover the laser emission port 8a, and the other surface 9c serves as a lever for rotating the shutter.

A torsion spring 11 is provided on the shaft 10 and urges the surface 9b of the shutter 9 to rotate so as to cover the laser emission port 8a. Therefore, the laser emission port 8a is always covered with the surface 9b unless the surface 9c serving as the lever (hereinafter referred to as the lever) is pressed.

The lever 9c is provided at a position where it is pressed by the pressing part 13 when the pressing part 13 provided on the upper cover 12 of the apparatus hangs down, and the upper cover 12 is closed. When the lever 9c is pressed, the lever 9c is pressed by the pressing portion 13 and the surface 9b is rotated upward to open the laser injection port 8a.

On the other hand, when the upper cover 12 is opened so as to be lifted up for replacement of parts or replenishment of toner, the lever 9c is released from the pressing by the pressing portion 13 and the torsion spring is released. The bias of 11 causes the shutter 9 to rotate the surface 9b downward to close the laser emission port 8a.

That is, when the upper cover 12 is opened, the shutter 9 closes the laser emission port 8a, and when the upper cover 12 is closed, the shutter 9 operates to open the laser emission port 8a. ing.

[0012]

[Problems to be solved by the device]

 Although the shutter operates as described above, if the cover is closed for a long time, the shutter remains open for a long time, and the toner or dust such as paper dust floating in the device is scanned by the laser. However, there is a problem in that it adheres to the dust-proof glass of the part and causes deterioration of the performance of the laser scanning part, which deteriorates the recording quality.

The present invention aims to improve the dustproof effect on the laser scanning unit by opening the shutter only when an electrostatic latent image is formed.

[0014]

[Means for Solving the Problems]

 In the present invention, as shown in the side view of FIG. 1, the laser scanning unit 4 is provided so as to face the laser emission port 8a of the case 8 and operates to open and close the laser emission port 8a. The shutter 13 and the shutter control circuit 14 for controlling the shutter 13 to be opened only during recording of emitting a laser beam.

[0015]

[Action]

 Since the shutter is controlled by the shutter control circuit to open only during recording when the laser beam is emitted, the opening time is reduced, and dust such as toner and paper dust floating inside the device is protected from dust in the laser scanning unit. The amount attached to the glass is reduced.

[0016]

【Example】

 In the present invention, as shown in the schematic view of FIG. 1, the laser scanning unit 4 is provided so as to face the laser emission port 8a of the case 8 and operates to open and close the laser emission port 8a. The shutter 13 and the shutter control circuit 14 that controls the shutter 13 to open only when the laser light is emitted.

That is, as shown in the perspective view of FIG. 2, the shutter 13 has a flat plate shape and is slidably mounted on the substrate 15 of the apparatus. The laser scanning unit 4 is accommodated in the lower portion of the substrate 15, and the substrate 15 is provided with a long hole 15a having the same length as the laser emitting port 8a at a position facing the laser emitting port 8a of the laser scanning unit 4. ing.

The shutter 13 slides on the substrate 15 so as to open and close the elongated hole 15a. As the sliding power, for example, the attractive force of the electromagnet 16 is used. The electromagnet 16 is excited according to a command from the shutter control circuit 14 and attracts the attraction piece 17.

Then, the suction piece 17 rotates clockwise around the support shaft 18 and moves the protrusion 17a provided at the other end in the same direction. The protrusion 17a is engaged with the groove of the engaging portion 13a provided upright on the end of the shutter 13, and the shutter 13 also moves in the same direction as the protrusion 17a moves.

Due to the movement, the laser emission port 8a is exposed through the elongated hole 15a, and the shutter 13 is opened. Here, when the excitation of the electromagnet 16 is cut off, the attraction piece 17 rotates counterclockwise around the support shaft 18 by the bias of the torsion bar 19 provided on the support shaft 18, and is provided at the other end. The stem 17a is moved in the same direction.

The shutter 13 also moves in the same direction as the protrusion 17a moves. Due to the movement, the long hole 15a is closed, the laser emission port 8a is closed, and the shutter 13 is closed.

As shown in the flow chart of FIG. 3, the shutter control circuit 14 detects when the upper control unit issues a drive signal for the laser scanning unit 4, delays the start of the laser scanning unit 4 and immediately starts the electromagnet 16. Emits a signal to excite.

Then, it is confirmed that the shutter 13 is opened by a sensor (not shown) or the like, or when a predetermined operation time of the shutter 13 has elapsed, a drive signal is issued to the laser scanning unit 4.

On the contrary, when the completion of the scanning by the laser scanning unit 4 is detected from the signal of the upper control unit, the excitation of the electromagnet 16 is immediately stopped. As a result, the shutter 13 is closed to prevent dust from entering the laser scanning unit 4.

By configuring the shutter 13 in this way, the shutter 13 is opened only during the scanning operation of the laser scanning unit 4, and the opening time is significantly reduced as compared with the prior art. ..

The reduction of the opening time reduces the amount of dust entering the laser scanning unit 4, delays the deterioration of its performance, and maintains high recording quality.

[0027]

[Effect of the device]

 According to the present invention, the time during which the laser scanning unit is closed by the shutter is extended, and the amount of dust entering is reduced.

As a result, it is possible to delay the deterioration of the performance of the laser scanning unit and maintain high recording quality.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electrophotographic recording apparatus of the present invention,

FIG. 2 is a perspective view of a shutter portion in the electrophotographic recording apparatus of the present invention,

FIG. 3 is a flowchart of a shutter control circuit used in the present invention,

FIG. 4 is a schematic view of an electrophotographic recording device to which the present invention is applied,

[Explanation of symbols]

1 image carrier (photosensitive drum), 4 laser scanning unit, 8 cases,
8a Laser emission port, 13 shutters,
13a engagement part, 14 shutter control circuit,
15 substrate, 15a long hole,
16 electromagnets, 17 adsorption pieces,
17a Mouthpiece, 18 support shaft,
19 torsion springs,

Claims (1)

[Scope of utility model registration request] 1. An electrophotographic recording apparatus comprising a laser scanning section (4) for irradiating a laser beam on the surface of an image carrier (1) to form an electrostatic latent image, wherein the laser scanning section (4) A shutter (13) that is provided so as to face the laser emission port (8a) of the case (8) that houses the laser beam and that operates to open and close the laser emission port (8a); An electrophotographic recording apparatus comprising: a shutter control circuit (14) that controls to open only when recording by emitting light.