JPH1124531A - Writing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a writing device whose structure is simpler than the conventional one, where the number of parts is reduced, whose assembly is facilitated and which can surely intercept a laser beam as necessary so that the laser beam may not be emitted to the outside of the device. SOLUTION: When an opening/closing cover 2 is closed, a coil spring 5 provided on the cover 2 is inserted inside the writing device through an aperture part and abuts on the rear surface of a reflection mirror 11. At such a time, the mirror 11 is pressed by the spring 5 and turned in the direction of an arrow B, so that it is pressed to both positioning members. After the laser beam L from an Fθ lens 10 is reflected by the mirror 11, it is emitted to the outside through an emitting window 12. Meanwhile, when the cover 2 is opened, the mirror 11 is turned to the side of an arrow A as the spring 5 is restored to original shape, and separated from both positioning members. In such a state, the laser beam L reflected by the mirror 11 is intercepted because it is radiated to a spot turned aside from the aperture part 12 on the base of a structural body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image by an electrophotographic process, and more particularly to a writing device for writing an electrostatic latent image pattern by irradiating a laser beam to a photosensitive member surface after charging. It is.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a digital copying machine, a laser printer, a laser facsimile, etc., which has a writing device using a laser beam, mechanical troubles such as paper jams and replacement of process cartridges, toners, etc. Therefore, precautions have been taken to prevent the laser beam from accidentally entering the user's eyes when the device cover is opened. FIG. 6 is a schematic perspective view showing the entire structure of such a conventional image forming apparatus, and is a device main body 2.
1 is provided with a cover 22 that can be opened and closed by a user in the event of a paper jam or replacement of a process cartridge. When the cover 22 is opened, the main body 24 of the writing device 23 in the main body 21 is exposed. I have. An opening 24a is formed near the right end of the front surface of the main body 24 of the writing device 23, and a projection 25 is provided on the rear surface of the cover 22 in accordance with the position of the opening 24a. In a normal state, that is, when the cover 22 is closed, the projection 25 is inserted into the main body 24 of the writing device 23 through the opening 24a,
When the cover 22 is opened, the projection 25 is pulled out from the opening 24a.

FIG. 7 is a perspective view showing the internal structure of the writing device 23. Structure 26 forming body 24 of writing device 23
, An LD unit 27, a lens 28, a polygon mirror 29, an Fθ lens 30, and a mirror 31 are attached. The laser beam L emitted from the LD unit 27 is first irradiated on the polygon mirror 29 through the lens 28, and is irradiated on the mirror 31 through the Fθ lens 30 while being swung right and left by the rotation of the polygon mirror 29. An emission window 32 is opened at the bottom of the structure 26 in parallel with the longitudinal direction of the mirror 31, and the laser beam L is reflected by the mirror 31 and then emitted to the outside of the writing device 24 through the emission window 32. . A mirror 3 is provided on the inner bottom surface of the structure 26 in order to keep the position and angle of the mirror 31 constant.
1 and a pair of positioning members 33, 3
3 is fixed. The positioning members 33, 33 are mirrors 3.
The mirrors 33, 33 are formed by a pair of leaf springs 34, 34 attached to the inner bottom surface of the structure 26, and the taper surfaces 33a of the two positioning members 33, 33 are formed. It is held in a state of being pressed against.

[0004] A shutter member 35 is provided on the optical path of the laser beam L from the Fθ lens 30 to the mirror 31. A pair of support bases 36, 36 for supporting both end portions of the shutter member 35 are provided on the inner bottom surface of the structure 26.
Are fixed, and the shutter member 35 is attached to both support bases 36,
It is supported by the mirror 36 and is held parallel to the mirrors 33 and 33 so as to be rotatable back and forth (in the directions indicated by arrows A and B in FIG. 8). It has a structure. At one end of the shutter member 35, a contact portion 37 with which the tip of the projection 25 of the cover 22 contacts is formed. At the other end, a spring 38 that constantly urges the shutter member 35 in the direction of arrow B, that is, so that the shutter member 35 blocks the optical path, is attached. One end of the spring 38 is hooked on the shutter member 35, and the other end is held by the support base 36.

FIGS. 8A and 8B show the movement of the shutter member 35 when the cover 22 is opened and closed. First, in FIG. 8A, since the cover 22 is closed, the protrusion 25 provided on the cover 22 is
The shutter member 35 is inserted into the writing device 23 through a. At this time, the shutter member 35 is pushed by the projection 25 and pivots in the direction of arrow A, and is in a state of being lifted out of the optical path of the laser beam L. In this state, since the laser beam L from the Fθ lens 30 is not blocked by the shutter member 35, the laser beam L is reflected by the mirror 31, is emitted outside through the emission window 32, and is irradiated on the photoconductor 15. On the other hand, when the cover 22 is open as shown in FIG.
5 is pulled back to the arrow B side by the force of the spring 38, and the shutter member 35 blocks the optical path of the laser beam L. At this time, since the laser beam L is not emitted from the emission window 32 or the opening 24a, there is no danger that the laser beam L will enter the user's eyes when the cover 22 is opened.

[0006]

However, the laser beam blocking mechanism in the above-described conventional writing device has a shutter member 35 for blocking the laser beam and a shutter member in the original configuration of the writing device. Since this is realized by adding a spring 38 for urging the 35, the structure of the entire writing device is complicated, it takes time to assemble the device, and the manufacturing cost is disadvantageously increased. Therefore, the problem to be solved by the present invention is that the structure is simpler than in the past, the number of parts is small, assembly is easy, and the laser beam is reliably emitted as necessary so that the laser beam does not exit the apparatus. An object of the present invention is to provide a writing device that can be shut off.

[0007]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 comprises a laser light source, a rotating mirror for oscillating a laser beam emitted from the laser light source in a scanning direction, and A reflector for guiding the laser beam from the rotating mirror to the outside of the device is disposed in a housing made of a light-shielding material, and the laser beam from the reflector is passed through the exit window opened at a predetermined position of the housing to the outside of the device. In a writing device configured to emit light to the mirror, holding means for holding the reflecting mirror at an angle variably, and an opening formed in the housing facing a surface different from the mirror surface of the reflecting mirror, for example, a back surface Part, an insert inserted into the housing from the opening to press the reflecting mirror, and when the pressing by the insert is released, the laser beam reflected by the reflecting mirror is Exit window To vary the angle of the reflecting mirror so as to irradiate the location is characterized by comprising a biasing means for constantly urging said reflector. According to the first aspect of the present invention, when the insertion body is inserted into the housing from the opening, the reflection mirror is pressed by the insertion body, and the reflection mirror is pressed against the urging force of the urging means. The laser beam is rotated until a predetermined angle is reached, and the laser beam reflected by the reflecting mirror is emitted from the emission window to the outside of the device. On the other hand, when the pressing by the insertion body is released, the reflecting mirror is rotated by the urging force of the urging means until the reflecting mirror reaches another predetermined angle, and the laser beam reflected by the reflecting mirror is turned on. The laser beam is blocked by the housing because the light is irradiated to a position deviating from the emission window in the housing. As described above, the angle of the reflecting mirror for guiding the laser beam to the outside of the apparatus is held variably, and the angle of the reflecting mirror is changed so that the laser beam is blocked by the housing. Since the provided shutter member and the like are not required, the number of parts can be reduced, assembling can be facilitated, and the laser beam can be reliably shut off as necessary so that the laser beam is not emitted out of the apparatus. . According to a second aspect of the present invention, in the writing apparatus according to the first aspect, a member having both a function as the holding unit and a function as the urging unit, for example, a leaf spring or a coil spring is used. By doing so, the number of parts can be further reduced.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a schematic perspective view showing the overall structure of an image forming apparatus provided with a writing device of the present invention. The apparatus main body 1 of the image forming apparatus can be opened and closed by a user when a paper jam or a process cartridge is replaced. An opening / closing cover 2 is provided, and when the cover 2 is opened, the main body 4 of the writing device 3 in the apparatus main body 1 is exposed. An opening 4a is formed in the center of the front surface of the main body 4 of the writing device 3,
A coil spring 5 as an insert is provided on the back surface of the opening / closing cover 2 in accordance with the position of the opening 4a. And
Normally, that is, when the cover 2 is closed, the coil spring 5 is inserted into the main body 4 of the writing device 3 through the opening 4a, and when the cover 2 is opened, the coil spring 5 is pulled out from the opening 4a. It has become. FIG. 2 is a perspective view showing the internal configuration of the writing device 3. A housing 6 forming a main body 4 of the writing device 3 includes an LD unit 7, a lens 8, a polygon mirror 9 as a rotating mirror, an Fθ lens 10,
And a reflecting mirror 11. LD unit 7
Is emitted to the polygon mirror 9 through the lens 8, and is irradiated to the reflecting mirror 11 through the Fθ lens 10 while being swung right and left by the rotation of the polygon mirror 9. A reflecting mirror 11 is provided at the bottom of the housing 6.
An emission window 12 is formed in parallel along the longitudinal direction of the laser beam L. The laser beam L is reflected by the reflecting mirror 11 and then emitted to the outside of the writing device 3 through the emission window 12. The reflecting mirror 11 is provided at a position where the coil spring 5 comes into contact with and is pressed against the back surface when the opening / closing cover 2 is closed. That is, when the opening / closing cover 2 is closed, the reflecting mirror 11 is constantly urged toward the mirror surface (the arrow B side) by the coil spring 5.

On the inner bottom surface of the housing 6, a pair of leaf springs 13, 13 bent in a V-shape, which are both holding means and biasing means for the reflecting mirror 11,
A pair of positioning members 14, 14 for regulating the angle and the position of the reflecting mirror 11 when is closed are fixed. The positioning members 14 and 14 are formed with tapered surfaces 14a and 14a corresponding to the inclination angle of the mirror 13. With the above configuration, the reflecting mirror 11 includes the two leaf springs 13,
The laser beam reflected by the reflecting mirror 11 is applied to a position deviating from the exit window 12 on the fixed surface inside the housing 6 when both ends are held by the coil 13 and the pressing by the coil spring 5 is released. In order to change the angle of the reflecting mirror 11 as described above, the reflecting mirror 11 is always urged by the two leaf springs 13. When the cover 2 is closed, the reflecting mirror 11 is pressed by the coil spring 5 from the back side.
Both ends of the mirror surface are tapered surfaces 1 of both positioning members 14, 14.
It is held in a state pressed against 4a and 14a. In this case, the pressing force (rotational power to the arrow B side) by the coil spring 5 is F ₁ , and the urging force (arrow A) by both leaf springs 13, 13 is applied.
When a rotational force) to the side and F _2, the relationship between the two, for example F
₁ > 2F ₂ and the coil spring 5
Is twice as strong as the force of the two leaf springs 13, 13. Therefore, when the opening / closing cover 2 is closed, the reflecting mirror 11 turns to the arrow B side against the force of the two leaf springs 13, 13. Then, the positioning members 14 and 14 are positioned in contact with each other.

FIGS. 3A and 3B show the opening / closing cover 2.
Shows the movement of the reflecting mirror 11 due to the opening and closing of. First, FIG.
5A, since the open / close cover 2 is closed, the coil spring 5 provided on the open / close cover 2 is connected to the opening 4.
a, and is inserted into the writing device 3 and is in contact with the rear surface of the reflecting mirror 11. At this time, the reflecting mirror 11 is
To rotate in the direction of arrow B, and the positioning members 14, 1
4 is pressed against the tapered surfaces 14a, 14a. In this state, the laser beam L from the Fθ lens 10 is reflected by the mirror 11, is emitted outside through the emission window 12, and is irradiated on the photoconductor 15. On the other hand, when the opening / closing cover 2 is open as shown in FIG. 3B, the reflecting mirror 11 turns to the arrow A side by the return of the coil spring 5 to the original shape, and the two positioning members 14 and 14. In this state, the laser beam L reflected by the reflecting mirror 11 is applied to a position deviated from the opening 12 on the bottom surface of the structure 4, so that the laser beam L is not emitted outside the writing device 3. Absent.
Further, since the opening 4a is behind the reflecting mirror 11, the laser beam L is not emitted from the opening 4a.
In the above example, the coil spring 5 is used as an insertion member for pressing the reflecting mirror 11 when the opening / closing cover 2 is closed, but the leaf spring 16 as shown in FIG.
Other elastic materials such as rubber may be used, and need not be elastic. In the above example, the reflection mirror 11 is used.
, A pair of V-shaped leaf springs 13,
13, for example, as shown in FIG.
The lower end of the reflecting mirror 11 is hingedly connected to the bottom surface of the structure 4 so that the reflecting mirror 11 can rotate in the directions of arrows A and B.
A pair of coil springs may be provided between the two mirror-side ends and the bottom surface of the structure 4 so as to urge in the direction of arrow A.

[0011]

As described above, according to the present invention, the following excellent effects can be exhibited. According to the first aspect of the present invention, the reflecting mirror for guiding the laser beam to the outside of the writing device is held at a variable angle, and the laser beam is blocked by the housing of the writing device by changing the angle of the reflecting mirror. This eliminates the need for a shutter member or the like provided in a conventional writing device, so that the number of parts can be reduced, assembly can be facilitated, and laser beams can be emitted outside the device as necessary. The laser beam can be reliably shut off. According to the second aspect of the present invention, since a member having both the function as the holding means and the function as the urging means is used, the number of parts can be further reduced as compared with the case of the first aspect. Therefore, assemblability can be further improved and assembling cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating an overall structure of an image forming apparatus including a writing device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an internal configuration of the writing device shown in FIG.

FIGS. 3A and 3B are explanatory views showing the movement of the reflecting mirror of the writing apparatus according to the present invention when the opening and closing cover of the image forming apparatus is opened and closed.

FIG. 4 is a schematic perspective view showing a general structure of an image forming apparatus including a writing device according to another embodiment of the present invention and an enlarged view of a main part.

FIG. 5 is a perspective view showing an internal configuration of a writing device according to another embodiment of the present invention.

FIG. 6 is a schematic perspective view showing the entire structure of an image forming apparatus including a conventional writing device.

FIG. 7 is a perspective view showing an internal configuration of the writing device shown in FIG. 7;

FIGS. 8A and 8B are explanatory views showing the movement of a reflecting mirror of a conventional writing device by opening and closing an opening and closing cover of an image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body, 2 opening / closing cover, 3 writing apparatus, 4 writing apparatus main body, 4a opening, 2 opening / closing cover, 5 coil spring, 7 LD unit, 8 lens, 9 polygon mirror (rotating mirror) 10 Fθ lens, 11 reflector, L laser beam, 12 emission window, 13 leaf spring (holding means, biasing means), 14 positioning member.

Claims (2)

[Claims] 1. A laser light source, a rotating mirror for oscillating a laser beam emitted from the laser light source in a scanning direction, and a reflecting mirror for guiding the laser beam from the rotating mirror to the outside of the apparatus, from a light shielding material. In a writing device arranged in a housing and configured to emit a laser beam from the reflecting mirror to the outside of the device through an emission window opened at a predetermined position in the housing, the reflecting mirror is held at a variable angle. Holding means, an opening formed in the housing facing a surface different from the mirror surface of the reflecting mirror, an insert inserted into the housing from the opening to press the reflecting mirror, When the pressing by the body is released, the reflecting mirror is changed to change the angle of the reflecting mirror so that the laser beam reflected by the reflecting mirror is irradiated to a position deviating from the exit window in the housing. Always attached And biasing means for,
A writing device comprising: 2. The writing device according to claim 1, wherein a member having both a function as said holding means and a function as said urging means is used.