JPH0534623A - Scanning optical device - Google Patents

Abstract

PURPOSE:To provide the scanning optical device having an optical vessel which is not influenced by internal heating and heat from the outside, in a containing vessel for containing a laser light source, a collimating optical system, a rotary mirror, and an image forming optical system. CONSTITUTION:A semiconductor laser unit (not shown in the figure), a collimating optical system (not shown in the figure), a rotary mirror 4, an image forming lens 9, and a motor 5 are contained in a containing vessel 1, and the ceiling part is covered with a cover 11 being an air filter having gas permeability. The motor 5 consists of a rotor 6, a stator coil 7, and a circuit board 8 for forming a chassis of the motor 5, and also, being a cooling body, and the rotary mirror 4 is fixed coaxially to a rotor 6. When an operation is started, air flows A, B are generated by a rotation of the rotor 6, and the inside of the containing vessel is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device for forming an image by scanning a laser beam modulated by an image signal on a photosensitive drum.

[0002]

2. Description of the Related Art Conventionally, a scanning optical device has been used in a laser beam printer and is easily deteriorated by the influence of heat. Therefore, the scanning optical device is arranged away from a heat source such as a fixing device of the laser beam printer, and the housing thereof. The container was molded with a material having a small thermal expansion, glass lenses were used for all the lenses, and the container was sealed to prevent dust from entering the optical system.

[0003]

The above-described conventional scanning optical device is made of a material which is kept away from the heat source and has a small thermal expansion in order to avoid the influence of heat. In recent years, however, the laser beam printer has been downsized. Along with this, the arrangement of the scanning optical device is limited, and the scanning optical device is arranged in the vicinity of the fixing device and the power source which are heat sources. Further, due to cost reduction, there is a tendency to use a plastic lens as the imaging lens. However, when a plastic mold lens is used as the imaging lens, the temperature rise is limited to about 10 ° C. On the other hand, since the container is in a sealed state or a structure close to it, the rotating mirror is driven even if the outside is cooled. Since the heat generated inside the motor is large, the heat stays inside the container and exceeds the limit temperature, causing the lens to expand and significantly impairing the imaging performance, which causes the problem that the laser beam printer cannot be downsized. ing.

An object of the present invention is to provide a scanning optical device having a container which is not affected by internal heat generation or external heat.

[0005]

A scanning optical device according to the present invention comprises at least a laser light source, a collimating optical system, and
The rotating mirror and the imaging optical system are housed in a single container, and the ceiling of the container has air permeability.

Characters and figures may be printed on the outer surface of the air-permeable ceiling portion.
The ceiling may be made of a conductive material.

[0007]

The laser light source, the collimating optical system, the rotating mirror, and the imaging optical system are housed in a container whose ceiling has air permeability, and the rotation of the rotating mirror allows the inside of the container to be ventilated by outside air. The rise in temperature inside the container is prevented.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view showing the scanning optical device according to the first embodiment of the present invention with the cover removed, FIG. 2 is a perspective view of the housing 1 shown in FIG. 1 with a cover 11 attached, and FIG. It is a longitudinal cross-sectional view including the axis of the rotating mirror 4.

This scanning optical device comprises a container 1, a semiconductor laser unit 2 and a collimating lens (not shown).
, Cylindrical lens 3, rotating mirror 4, motor 5
And the imaging lens 9. The container 1 is an optical container that houses the semiconductor laser unit 2, a collimator lens (not shown), a cylindrical lens 3, a rotating mirror 4, a motor 5, and an imaging lens 9, and a removable cover 11 is always attached as a ceiling part. Has been. The motor 5 is the rotor 6
And a stator coil 7 and a circuit board 8. The rotating mirror 4 is fixed to the rotor 6 of the motor 5 with the same axis and rotates at about 8,000 rpm. Reflect to. The imaging lens 9 is fixed to the side wall on the light exit side of the container 1, and images the laser beam reflected by the rotating mirror 4 on the photosensitive drum 10 for imaging. The circuit board 8 is a single metal board on which the motor driver IC and the laser driver IC are mounted, and forms the chassis of the motor 5. Therefore, the circuit board 8 has both an electric shield effect and a heat dissipation effect, and the stator coil 7 which is a heating element,
The heat from each driver IC is efficiently dissipated. Further, since the circuit board 8 has a configuration that spreads around the rotor 6,
The airflow generated by the rotation of the rotary mirror 4 easily flows on the surface, further enhancing the cooling effect. The cover 11 is an air filter in which the fineness is hardened at a constant density, and has dustability of 5 microns or more and has air permeability.

Next, the cooling operation of the first embodiment will be described.

When the operation of this scanning optical device is started,
The rotating mirror 4 rotates clockwise by about 8,0 by the rotation of the motor 5.
Rotate at 00 rpm. Due to the rotation of the rotary mirror 4, an airflow is generated through the cover 11 as shown by arrows A and B in FIG. 3, and heat generated from the stator coil 7, the laser driver IC, and the motor driver IC of the housing container 1 is made of metal. The circuit board 8 is cooled by heat conduction. The area of the circuit board 8 promotes heat dissipation of each driver IC and the stator coil 7, but when continuously energized in a closed space, the temperature rises and is a limit temperature inside the housing container 10. It exceeds ℃. The air flow A from the outside air sucked through the cover 11 flows along the surface of the circuit board 8 following the air flow B generated by the rotation of the rotating mirror 4 and the rotor 6 and flowing out of the container to cool the circuit board 8. In addition, it is possible to suppress a slight temperature rise.

Further, on the outer surface of the cover 11, for example, laser cautions, symbols and the like specified in safety standards can be directly printed. In the past, a printed label was pasted on the cover, but in order to maintain air permeability, direct printing is preferable rather than sticking the label.

The second embodiment of the scanning optical device of the present invention is configured such that the material of the cover 11 shown in FIG. 1 is a conductive fine material of an air filter structure. By connecting this conductive filament to the ground, the radiation of RFI noise can be shielded and prevented, and at the same time, the air cooling effect can be achieved.

FIG. 4 is a vertical sectional view including the axis of the rotary mirror 4 of the third embodiment of the scanning optical apparatus of the present invention.

In this scanning optical device, a partition plate 12 is fixed to the inner surface of a cover 11, is provided at an angle along the air flow generated by the rotation of the rotating mirror 4 and the rotor 6, and the air inside the container 1 is It is possible to avoid confusion with the inflowing outside air and to efficiently suck the outside air into the container 1.

[0017]

As described above, according to the present invention, the cover of the container is made of the air permeable material, and the outside air is sucked into the container by the air flow generated by the rotation of the rotary mirror to store the optical container. It has the effect of increasing the cooling effect inside, the use of plastic molded lenses, the effect of downsizing the scanning optical device, and the effect of shielding the electrical noise by making the breathable material of the cover conductive. There is also.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a cover of a scanning optical device according to a first exemplary embodiment of the present invention is removed.

FIG. 2 is a perspective view when a cover 11 is attached to the storage container 1 of FIG.

FIG. 3 is a vertical cross-sectional view including the axis of the rotary mirror 4 of FIG.

FIG. 4 is a vertical cross-sectional view including an axis of a rotary mirror 4 according to a third embodiment of the scanning optical device of the present invention.

[Explanation of symbols]

 1 Storage Container 2 Semiconductor Laser Unit 3 Cylindrical Lens 4 Rotating Mirror 5 Motor 6 Rotor 7 Stator Coil 8 Circuit Board 9 Imaging Lens 10 Photosensitive Drum 11 Cover 12 Partition Plate

Claims (3)

[Claims] 1. A scanning optical device having a laser light source that emits laser light modulated by an image signal, a collimating optical system, a rotating mirror, and an imaging optical system, at least a laser light source, a collimating optical system, and A scanning optical device in which a rotating mirror and a ceiling of a container in which an imaging optical system is housed in one container have air permeability. 2. The scanning optical device according to claim 1, wherein characters and figures are printed on the outer surface of the ceiling portion having air permeability. 3. The scanning optical device according to claim 1, wherein the air-permeable ceiling portion is made of a conductive material.