JPS61238013A - Photoscanner - Google Patents

Abstract

PURPOSE:To reduce a photoscanner in size on the whole by arranging a rotary mirror so that its reflecting surface side faces the center of the device and then providing a driving part which rotates the rotary mirror in this rotary mirror. CONSTITUTION:A laser beam irradiated by a laser head 28 is returned by a primary reflecting mirror 30 to strike a reflecting surface 13 again. The return light which is reflected again by the reflecting surface 13 passes through an f0 lens 31 to strike a photosensitive drum 35 through a secondary reflecting mirror 33. In this case, the rotary mirror 12 is rotted by the driving part 14 and then the angle of reflection of the laser beam reflected by the reflecting surface 13 varies to cause an axial shift in the position of incidence on the photosensitive drum 35, thereby forming a scanning line. Consequently, a specific latent image can be formed on the photosensitive drum 35 to attain optical recording. The coil 20 of the driving part 14 serves as a stator and the magnet 21 serves as a rotor; and the coil 20 is fed with electricity to rotate a rotating shaft 19 where the magnet 21 is fixed and the rotary mirror fixed thereupon rotates.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical scanning device that performs optical recording by scanning with a single laser beam.

BACKGROUND OF THE INVENTION Recently, research has been carried out on optical recording by scanning a single laser beam.

An example of this will be explained with reference to FIGS. 6 and 7. A polygon mirror 2 is provided which is driven by a motor 1 to rotate. This polygon mirror 2 has a flat octagonal column shape, and has a mirror 3 on each side. A laser head 4 for irradiating a laser beam is provided on one of the mirrors 3, and a photosensitive drum 7 is provided for receiving the laser beam reflected by the mirror 3 via an FO lens 5 and a reflecting mirror 6. ing.

With such a configuration, the laser beam irradiated from the laser head 4 is reflected by the mirror 3 to become reflected light, and f
It reaches the reflection 1It6 via the o lens 5. Then, the direction of travel is changed by reflection [6, and the light is incident on the photosensitive drum 7. At this time, when the polygon mirror 2 is rotated by the motor 1, the reflection angle of the laser beam on the mirror 3 changes, and the incident position of the laser beam on the photosensitive drum 7 moves in the direction of its axis. Here, a scanning line is formed on the photosensitive drum 7, and a latent image is formed at the position where the scanning line is formed, and is used for optical recording.

Problems to be Solved by the Invention The optical length from the mirror 3 to the reflection IIt6 requires a certain length, and it is difficult to shorten it. For this reason, the overall length of the device is limited by its optical length, forcing it to be longer. However, since the motor 1 and the parabon mirror 2 are also arranged extending in the optical length direction, the entire device becomes even longer.

The present invention has been made in view of the above points, and an object of the present invention is to provide an optical scanning device that can reduce the size of the entire device.

Means for Solving the Problems The present invention provides a rotating mirror having a plurality of reflective surfaces inclined at a predetermined angle with respect to the central axis, and a laser head for irradiating the reflective surfaces with a laser beam. A two-sided reflector is provided, which reflects the laser beam reflected from the reflecting surface at right angles and returns it to the reflecting surface again. A drive unit for rotating the rotating mirror was provided inside the mirror.

When a laser beam is emitted from the laser head, the laser beam is reflected in the order of the reflecting surface, the dihedral reflecting mirror, and the reflecting surface, and is incident on a predetermined position.

When the mirror is rotated once, the reflection angle of the laser beam on the reflecting surface changes, and a scanning line is formed at the laser beam incident position, which is used for optical recording.

On the other hand, the overall size of the device can be reduced by changing the positions of the single-rotation mirror and the drive unit. This is because there is a limit to the shortening of the optical length required to make the laser beam enter a predetermined position from one reflecting surface, but the rotating mirror is arranged so that the length is shortened in the optical length direction. Also, the drive unit is disposed inside the rotating mirror.

Embodiment of the Invention A first embodiment of the present invention will be described based on FIGS. 1 to 4. FIG. A housing-like case 10 is provided, and an umbrella-shaped rotating flt 12 is rotatably attached to a surface 11 on one side of the interior. This rotating jll 12 is made of a plastic member having a shape in which each side of an octagonal prism is inclined at a predetermined angle in the direction of its axis, and reflective surfaces 13 are provided on those sides.
is formed. A drive unit 14 is disposed inside the rotation fi12 to apply a driving force to the rotation #112 to rotate it. That is, a frame 17 is provided that has mounting holes 15 at three locations on the outer periphery and a shaft hole 16 in the center, and a cylindrical rotating shaft 19 is rotatably inserted into the shaft hole 16 via a holding part 18. is inserted into. A plurality of coils 20 are fixed to the frame 17 around the rotating shaft 19, and a doughnut-shaped magnet 21 facing the coils 20 is fixed to the rotating shaft 19 with an adhesive 22. . Here, the rotation i
! t12 has an insertion hole 23 in its center and a space 24 inside. And the rotation 1i12 is.

The coil 20 and the magnet 21 are placed in the space 24.
It is press-fitted into the rotating shaft 19 and fixed thereto until it is covered. Further, the end of the rotation shaft 19 has the rotation #! A pin 25 is installed to prevent removal of 12,
An E-ring 26 is attached to the other end to prevent the rotary shaft 19 from being removed. However, the frame 1
7 is mounted through a hole 15 to the surface 11 via a spacer 27, and therefore, the reflective surface 13 of the rotation #112 is disposed facing toward the center of the case 10.

On the other hand, the mounting inside the case 10 includes a laser head 28°-order reflecting mirror 2 on the side of the surface 11 that irradiates the laser beam.
9. A dihedral reflecting mirror 30 and an fO lens 31 are respectively arranged at predetermined positions. The second-order reflection fi 29 is disposed at a position where the laser beam irradiated from the laser head 28 can be bent at right angles in the traveling direction to be incident on the reflection surface 13. The two-sided reflective mirror 30 has two right-angled mirrors.
It has a right-angled reflective surface 32 composed of two surfaces, and is arranged at a position where the laser beam reflected by the reflective surface 13 can be returned by the right-angled reflective surface 32 and returned to the reflective surface 13 again. The fO lens 31 is arranged at a position where the returned light reflected by the reflective surface 13 can be incident and collected.

A secondary reflecting mirror 33 is disposed on the side facing the mounting surface 11 in the case 10 to receive the laser beam that has passed through the FO lens 31 and bend the traveling direction of the laser beam at an acute angle. has been done.

The case IO is provided with a passage hole 34 for passing the laser beam reflected by the secondary reflection #133 to the outside of the case 10. Furthermore.

Outside the case 10, there is a cylindrical photosensitive drum 3 that ultimately receives the laser beam that has passed through the passage hole 34.
5 is rotatably provided.

In such a configuration, the laser beam irradiated by the laser beam 28 reaches the reflective surface 1 via the -order reflection @29.
3, the light is returned to the dihedral reflecting mirror 30, and then enters the reflecting surface 13 again. Then, the returned light reflected again on the reflective surface 13 passes through the fo lens 31 and is secondary reflected jJi3.
3 and enters the photosensitive drum 35. At this time, when the one-turn mirror 12 is rotated by the drive unit 14, the reflection angle of the laser beam reflected by the one-reflection surface 13 changes, and the incident position on the photosensitive drum 35 moves in the axial direction of the photosensitive drum 35, forming a scanning line. Ru. Here, a predetermined latent image can be formed on the photosensitive drum 35 and used for optical recording. In addition,
In the drive unit 14, the coil 20 serves as a stator,
The magnet 21 serves as a rotor, and by energizing the coil 20, a rotating shaft 19 that fixes the magnet 21 rotates, and a rotating shaft fi12 fixed thereto rotates.

Thus, in the dihedral reflection @30, the laser beam is bent by the right-angled reflective surface 32 and returned to the reflective surface 13. As a result, the incident light and the reflected light on the dihedral reflecting mirror 30 travel in parallel.

The second incident light and the second reflected light on the reflecting surface 13 become parallel. Therefore, even if the reflecting surface 13 is misaligned, the same traveling direction of the laser beam is maintained, and reliable recording is guaranteed.

Here, it becomes possible to form the rotating mirror 12 using plastic, which is difficult to form with high precision.

The weight of the rotating mirror 12 can be reduced. In addition, along with this, the drive unit I4 can also be configured to be small and lightweight, and therefore,
The entire device can be made smaller and lighter.

On the other hand, the overall size of the device is also reduced by the arrangement positions of the rotating mirror 12 and the drive unit 14. That is, 1 reflective surface 1
There is a limit to shortening the optical length from fi 3 to secondary reflection fi 33, and the device has no choice but to become longer in the optical length direction.

Therefore, it is advantageous to shorten the overall length of the device by arranging as few members as possible at positions that extend beyond the optical length.

In this regard, in this embodiment, the U transreader 12 is arranged with the entire surface of the reflective surface 13 facing toward the center of the case 10, and furthermore,
A drive unit 14 is disposed inside the rotating mirror 12.

Therefore, the amount of extension of the member from the optical length is reduced, the overall length of the device is shortened, and the overall device can be miniaturized.6 A second embodiment of the present invention is shown in FIG. explain. The same parts as in the first embodiment are denoted by the same reference numerals and explanations will be omitted. In this embodiment, a groove 3 is provided at the end of one rotation axis I9.
6, and a base 37 on which the rotating mirror 12 is formed at the end thereof was injection molded so as to cover this groove 36. With this,! The two-manufacturing process is simplified, and the device can be manufactured easily and quickly.

Effects of the Invention The present invention includes an umbrella-shaped rotating mirror having a plurality of reflective surfaces, and a two-sided reflective mirror that corrects the traveling direction of the laser beam emitted from the laser head and reflected by the reflective surface. By arranging the rotating mirror so that it faces toward the center of the device, and by arranging the drive section inside this rotating mirror, the entire device can be made more compact, resulting in a more practical device. have an effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a rotating mirror and a drive unit showing a first embodiment of the present invention, FIG. FIG. 5 is a partially cross-sectional front view, and FIG. 5 is a longitudinal cross-sectional side view of a rotating mirror and a drive unit showing a second embodiment of the present invention. FIG. 6 is a side view showing a conventional example, and FIG. 7 is a plan view thereof. l2...Rotating mirror, 13...Reflecting surface, 14...Driving section. 28...Laser head, 30...Double reflecting mirror, 32
...Right angle reflective surface Applicant: Tokyo Electric Co., Ltd. 3" Figure, %Z country, 7) 6 bacteria (Japanese)

Claims (1)

[Claims] A rotating mirror having a plurality of reflective surfaces inclined at a predetermined angle with respect to a central axis is provided, a laser head is provided for irradiating a laser beam onto the reflective surface, and the laser beam irradiated by the laser head and reflected by the reflective surface is A two-sided reflective mirror is provided that reflects the light on a right-angled reflective surface and returns to the reflective surface again, and the rotating mirror is arranged with the reflective surface side facing the center of the device,
An optical scanning device characterized in that a drive unit for rotating the rotating mirror is disposed inside the rotating mirror.