JPS61151670A - Laser recording device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of the unevenness of the density of a picture due to reflected light by installing the surface of a transparent body for sealing provided in a through hole that leads laser light to a sensitive body so as to incline the surface to the vertical plane of the optic axis of laser light. CONSTITUTION:The laser light from an oscillator passes through a lens, a light modulator arranged along the optic axis and arrives at a mirror 9. The rays of light are reflected by the mirror 9 and made incident on a dust proof glass 12 and arrives at a photosensitive drum 10 through the through hole. In such a case, even when a part of light 15 is reflected by the surface of the glass 12, reflected light 15a is deviated from the optic axis of light 15 by an angle 2phi and hardly enters a rotary polyhedral mirror again. Further, even when light 15 reflected by the surface of the drum 10 is reflected again by the back of the glass 12, reflected light 15b is deviated from the optic axis by an angle 2phi and hardly irradiated again to the drum 10. Accordingly, the occurrence of unevenness of the density of a picture on the drum 10 due to lights 15a, 15b can be prevented.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a laser recording device.

[Prior art]

Generally, as shown in FIG. 2, the exposure optical system in a laser recording apparatus includes a beam expander lens 2, an optical modulator 3, and a beam expander lens 4 along the optical axis of a laser beam output from a laser oscillator 1. , a cylindrical lens 5, a rotating polygon mirror 6, an fθ lens 7, and a cylindrical lens 8 are arranged in this order.

A horizontal synchronous photodetector 11 that determines the starting position for recording an image on the surface of the photoreceptor drum 10 is provided outside the image area in the same plane as the image forming surface of the photoreceptor drum IO, and an exposure optical system and the photosensitive drum 10,
A dust-proof glass 12 is provided around a part of the photosensitive drum IO to prevent the exposure optical system from becoming dirty due to scattering of toner or the like in a developing system (not shown).

In such a laser recording device, conventionally, the dustproof glass 12 is equipped with an exposure optical system (part of which is shown by a rotating polygon mirror 6, an fθ lens 7, a cylindrical lens 8, and a mirror 9), as shown in FIG. , the optical axis of the laser beam 15 guided from the mirror 9 to the photoconductor drum IO is inserted into a passage hole 14 for the laser beam 15 formed in an optical bench 13 that separates the photoconductor drum 10 from a developing system (not shown) provided around the photoconductor drum 10. It was mounted perpendicular to the

However, in such conventional methods, the fourth
As shown in the figure, the laser beam 15 that enters the dust-proof glass 12 from the mirror 9 is partially reflected by the surface of the dust-proof glass 12, and this reflected light 15a (indicated by a dashed line) is transmitted to the rotating polygon mirror 6.
Since the laser beam re-enters the photosensitive drum 10 and scans the photosensitive drum 10 again, uneven density of the image occurs, and the laser beam reflected on the surface of the photosensitive drum IO is reflected again on the back surface of the dustproof glass 12, and this reflected light 15b (indicated by a broken line) had the disadvantage that 4-degree unevenness of the image occurred because the photoreceptor drum 10 was irradiated again.

In addition, some conventional products have anti-reflection films coated on both the front and back surfaces of the dustproof glass 12 in order to minimize the reflected light 15a and 15b, but anti-reflection film coatings are expensive and cost increases. It had the disadvantage of being unavoidable.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the conventional devices as described above, and to provide a laser recording device that can prevent density unevenness in images due to reflected light without coating with an antireflection film. shall be.

[Structure of the invention]

The present invention provides a laser recording apparatus that scans and exposes a photoreceptor with laser light and develops the exposed photoreceptor.
A transparent body for sealing is installed in a passage hole that guides the laser beam to the photoreceptor in order to separate the exposure optical system and the development system,
Its surface is relative to a plane perpendicular to the optical axis of the laser beam.
Jm has a configuration in which it is installed diagonally.

[Embodiments of the invention]

An embodiment of the invention shown in the drawings will be described below.

FIG. 1 shows the main parts of an embodiment of a laser recording apparatus according to the present invention, and FIG. 2 shows the general configuration.

This laser recording device has an exposure optical system and a development system.
The exposure optical system includes a laser oscillator 1, a beam expander lens 2, a luminous intensity II device 3, a beam expander lens 4, a cylindrical lens 5, a rotating polygon mirror 6, and an fθ
It consists of a lens 7, a cylindrical lens 8, and a mirror 9 disposed at the rear thereof, and a developing system is a part (not shown) provided around the photosensitive drum IO.

Further, the exposure optical system and the development system are separated by an optical bench 13, and the optical bench 13 has a hole 1 through which the laser beam 15 passes.
4 is provided, and this passage hole 14 is provided with a dustproof glass 1.
2 is mounted at an angle φ with respect to a plane perpendicular to the optical axis of the laser beam 15 guided from the mirror 9 side to the photoreceptor drum IO.

Next, the operation of the above will be explained.

First, the laser beam 15 output from the laser oscillator l is transmitted through a beam expander lens 2 disposed along the optical axis.
The light passes through the optical modulator 3, beam expander lens 4, cylindrical lens 5, rotating polygon mirror 6, fθ lens 7, and cylindrical lens 8, reaches the mirror 9, and is reflected by the mirror 9 onto the dust-proof glass 12. The light enters the photosensitive drum 10 through the passage hole 14.

In this case, even if the laser beam 15 that enters the dust-proof glass 12 from the mirror 9 is partially reflected by the surface of the dust-proof glass 12, the reflected light 15a is at an angle of 2
Since the laser beam is shifted by φ, it does not enter the rotating polygon mirror 6 again, and even if the laser beam 15 reflected on the surface of the photoreceptor drum 1O is reflected again on the back surface of the dustproof glass 12, this reflected light 15b is at an angle of 2 from the optical axis of the laser beam 15.
Since the light is shifted by φ, the photosensitive drum 10 is not irradiated again, and therefore the reflected light 15a, 15
b, there is no possibility that density unevenness will occur in the image on the photoreceptor drum 10.

Note that in order to prevent the laser light reflected from the photoreceptor drum IO from being reflected again on the back surface of the dust-proof glass 12 and reaching the photoreceptor drum 10, it is necessary to direct the laser light toward the center of the photoreceptor drum 10. , the distance from the back of the dustproof glass 12 to the center 0! , when the radius of the photosensitive drum is R, j! It is preferable that s in2φ≧R.

〔Effect of the invention〕

By having the above-described structure, the present invention can reliably prevent the occurrence of density unevenness in images due to the reflected light of the laser beam, even if the reflected light of the laser beam occurs on the front and back surfaces of the transparent body for sealing. Furthermore, since the anti-reflection film does not need to be inked at the corners, it has excellent effects such as being able to prevent the occurrence of density unevenness in images without increasing costs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of essential parts showing an embodiment of a laser recording device according to the present invention, FIG. 2 is an explanatory diagram showing the official configuration of the laser recording device, and FIG. 3 is an explanatory diagram showing an example of a conventional one. , FIG. 4 is an explanatory diagram showing the operation of the device shown in FIG. 3. 1... Laser oscillator 2.4... Beam expander lens 3...
...Light modulator 5.8 ... Cylindrical lens 6 ...
... Rotating polygon mirror 7 ... fθ lens 9 ... Mirror lO ... Photosensitive drum 11 ... Horizontal synchronization photodetector 12 ...・Dust-proof glass 13... Optical bench 14... Passing light 15... Laser light 15aS15b... Reflected light Fig. 1 Fig. 2 Fig. 3 Fig. 4 figure

Claims (4)

[Claims] (1) In a laser recording device that scans and exposes a photoreceptor with laser light and develops the exposed photoreceptor, the laser beam is guided to the photoreceptor in order to separate the exposure optical system and the development system. A laser recording device characterized in that a sealing transparent body installed in the hole is installed so that its surface is inclined with respect to a plane perpendicular to the optical axis of the laser beam. (2) The laser recording apparatus according to claim 1, wherein the scanning of the laser beam is performed using a rotating polygon mirror. (3) The laser recording device according to claim 1, wherein the photoreceptor is formed into a drum shape. (4) The laser recording apparatus according to claim 1, wherein the transparent body is made of dust-proof glass for preventing the exposure optical system from becoming dirty due to scattering of toner or the like in the developing system.