JPS62144129A - Rotary polygonal mirror unit - Google Patents

Abstract

PURPOSE:To effectively use an air current generated in an internal to cool a semiconductor laser efficiently by providing an air flow passage connecting a partrequiring cooling and a part near a rotary polygonal mirror. CONSTITUTION:A case 8 covers a rotary polygonal mirror 5 and a motor 6 except air supply and discharge holes 9. A ventilation flue 10 leads the air current from one of air supply and discharge holes 9 to a semiconductor laser 1. A hole 11 is provided in the front end of the ventilation flue 10 directed to the part requiring cooling. When the rotary polygonal mirror is rotated, air is flowed in from the air supply hole 9 and passes the ventilation flue 10 and is discharged from the front end of the ventilation flue 10. The semiconductor laser 1 is cooled by this discharged air. As the result, a stable output is obtained from the semiconductor laser 1 and its life is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to facsimiles, printers, and other image recording devices that record characters and images by scanning a recording medium by reflecting a modulated light beam with a reflecting mirror. This invention relates to a rotating polygon mirror unit.

FIG. 3 shows the arrangement of only the main components of the laser scanning system in the conventional LBP. In FIG. 3, a laser beam 32 emitted from a semiconductor laser 31 is converted into parallel light by a spherical lens 33, and converged by a converging lens system 34 toward a rotating polygon mirror 35, which is a beam polarizer. . Here, 36 is a drive motor for the rotating polygon mirror. The laser beam that has reached the rotating polygon mirror 35 is polarized here, passes through the converging lens system 37, and reaches the recording medium 3. As the laser beam is scanned over the recording medium, the recording medium 38 is exposed to light or heat, leaving an image record (or latent image) in a predetermined pattern.

In the laser scanning system as described above, an example of a conventional rotating polygon mirror unit will be described below with reference to the drawings.

FIG. 4 shows a side sectional view of a conventional rotating polygon mirror unit. In FIG. 4, numbers 41 to 46 are the same as those in FIG. 3, and 49 is a case that covers the rotating polygon mirror 45 and the drive motor 46 of the rotating polygon mirror in order to suppress wind noise from the polygons. be. Reference numeral 50 designates a cover made of transparent resin or the like that covers the surface on which the laser is incident and reflected for the same purpose.

51 is a laser 41, lenses 43 and 44, and a rotating polygon mirror 45.
, is a part of the main body board to which the motor 46 is attached. Here, what is shown in FIG. 4 will be referred to as a rotating polygon mirror unit.

Problems to be Solved by the Invention However, in the above configuration, the semiconductor laser 41
The temperature rises during operation. That is, when the semiconductor laser 41 is operated, heat is generated in the active region, and (
The resistance of the element cannot be reduced to zero, and the temperature increases. )
The temperature of the atmosphere around the semiconductor laser 41 also rises, and the temperature of the laser gradually rises. Therefore, when the temperature changes, the following problems occur.

(1) The open current (the current that starts laser oscillation) changes and the output power fluctuates. As a result, the dot diameter is not stable and the wire diameter changes.

(ii) 71! ! As the temperature increases, the emission wavelength becomes softer toward the wavelength side. The spectral sensitivity distribution of the recording medium is Furano 1-
Therefore, the amount of light is equivalently insufficient, and the output image becomes pale. (iii) Semiconductor lasers deteriorate at an accelerated rate at high temperatures.

In view of the above-mentioned problems, the present invention provides a rotating polygon mirror unit that stabilizes both the dot diameter and the output image by keeping the temperature of the semiconductor laser low, thereby extending the life of the semi-four-body laser.

Means for Solving the Problems (1) In order to solve the problems described above, the rotating polygon mirror unit according to the present invention is provided with an airflow passage connecting a portion that requires cooling and the vicinity of the rotating polygon mirror. It is something that

Effect of the Invention With the above-described configuration, the present invention allows the air flow generated by the rotation of the rotating polygon mirror to be applied to a portion that requires cooling, thereby suppressing a temperature rise in that portion.

Example Below, regarding a rotating polygon mirror unit according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 is a front sectional view of an embodiment of the present invention, and FIG. 2 is a plan view thereof. In the drawings, 1 is a semiconductor laser, 2 is a laser beam, 3 is a spherical lens, 4 is a convergent lens system, 5 is a rotating polygon mirror, 6 is a motor, and 7 is a part of the main body substrate. The above components are similar to those of the conventional example. 8 is a case that covers the rotating polygon mirror 5 and the mokuro except for the air intake hole and the exhaust hole 9. IO is a ventilation path that guides air flow from either one end of the large air supply hole or the exhaust hole 9 to the semiconductor laser 1. Reference numeral 11 denotes a hole at the tip of the ventilation path directed toward a portion requiring cooling. 12 is a cover that covers the reflective surface.

In the rotating polygon mirror unit configured as above,
As the rotating polygon mirror rotates, air flows in through the air intake hole 9, passes through the ventilation path 10, and is discharged from the tip of the ventilation path 10. The semiconductor laser 1 is cooled by the discharged air. As a result, a stable output can be obtained from the semiconductor laser 1, and its life can be extended. Note that the same effect can be expected even if the direction of the air flow is reversed.

Further, in the above embodiment, a configuration in which the case 8 covering the rotating polygon mirror 5 and the motor 6 is removed can also produce the above effects, although the efficiency decreases.

Further, instead of cooling the half-quad laser, they may be cooled by directing the end hole of the ventilation path toward the light source of the fixing device or the reading section.

Effects of the Invention As described above, the present invention provides an air flow path that connects the part that requires cooling and the vicinity of the rotating polygon mirror.
Efficient cooling can be achieved by making use of the air flow generated inside the device without providing a special cooling device such as a fan.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a polygon mirror unit according to an embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is a perspective view of main parts of the laser scanning system in L B P, and the fourth part is a conventional one. FIG. 3 is a side sectional view of the rotating polygon mirror unit of FIG. 1... Semiconductor laser, 5... Rotating polygon mirror, 8... Case, 9... Air intake hole,
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Claims (3)

[Claims] (1) A rotating polygon mirror that reflects and scans the beam, a rotating means that rotates the rotating polygon mirror, a cooling unit that is cooled by an air flow generated by the rotation of the rotating polygon mirror, and the cooling unit and the rotating polygon mirror. A rotating polygon mirror unit comprising: a ventilation path for the air flow that connects the vicinity of the polygon mirror; (2) The rotating polygon mirror unit according to claim (1), wherein the cooling section is a semiconductor laser. (3) The rotating polygon mirror unit according to claim (1) or (2), characterized in that an air intake hole or an air exhaust hole is opened inside the means for covering the rotating polyhedron.