JPH0392811A - Optical scanner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical scanning device used in an image forming apparatus or the like, and particularly relates to an optical scanning device equipped with a synchronization detection device using an optical fiber.

[Conventional technology]

Generally, in image forming devices such as electrophotographic copying machines, laser printers, high-speed facsimile machines, and large displays, a light beam modulated by an image signal is scanned by a rotating deflector using a polygon mirror, etc., and then An image is formed by adding sub-scanning.

At this time, in order to resolve jitter in the main scanning direction due to angle errors of the polygon mirror, etc., a synchronization detection device is installed that detects the light beam in a predetermined direction on the main scanning line and outputs a synchronization signal immediately before the start of modulation. inputs the image signal after a predetermined time delay after inputting the synchronization signal, and controls the operation of each part so as to start modulating the light beam.

In order to detect a light beam in a predetermined direction, a light receiving element may be provided at a detection point on the main scanning line. Some devices transmit incident light to a provided light-receiving element through an optical fiber to prevent malfunctions due to noise intrusion.

The input end of the optical fiber must be securely fixed to the housing of the optical scanning device, but if it remains fixed, the optical fiber cable will be damaged when the optical scanning device is connected to and removed from the main body of the device during the assembly or repair process. It gets in the way and greatly impairs work efficiency. Therefore, as shown in the cross-sectional view of FIG. 6 and the perspective view of FIG.
is adapted to be removably attached to a mounting portion 6 provided on the housing 5 of the optical scanning device.

The input end 2 of the optical fiber 1 consists of an input surface 1a and a plug portion 2a, and an engagement piece 2b is fixedly provided on the plug portion 2a.

The holding member 3 that also holds the condensing lens 7 has a collar portion 31, a socket portion 32, and an elastic claw 32a that are integrally molded.

The optical fiber 1 is held by the holding member 3 with the plug portion 2a fitted into the socket portion 32 and the engaging collar 2b locked with the elastic claw 3i2a.

The holding member 3 is inserted into a mounting portion (hole) 6 of the housing 5, and its collar portion 31 is screwed into a not-illustrated screw hole of the mounting portion 6, so that it is removably mounted to the housing 5.

[Problem to be solved by the invention]

However, since some looseness inevitably remains in the fitting between the socket portion 32 of the holding member 3 and the plug portion 2a of the input end 2 of the optical fiber 1, force may be applied to the long cable portion of the optical fiber or it may be twisted. If this happens, the optical axis will shift. That is, as shown in FIG. 8(A), it is sufficient that the incident surface 1a of the optical fiber 1 is on the optical axis of the condenser lens 7, but as shown in FIG. 8(B), there is no force on the optical fiber 1. If the incident surface 1a is deflected due to the addition of light, the amount of light that enters the optical fiber 1 may decrease or may not enter at all.

Therefore, it is necessary to securely fix the optical fiber 1 to the holding member 3.

However, if it is not possible to insert a screwdriver and remove the screw due to the mounting position of the optical scanning device on the device body or its relative position with the surrounding area, the optical fiber 1 must be removed from the holding member 3. Therefore, it was not possible to securely fix the optical fiber 1.

This invention has been made in view of the above points, and provides an optical scanning device that has excellent workability during assembly, adjustment, and repair, and that provides stable synchronization timing even when force is applied to the optical fiber cable section. The purpose is to provide the following. [Means for Solving the Problems] In order to achieve the above object, the present invention includes a deflecting means for repeatedly deflecting a light beam modulated by an image signal at a constant angle to perform main scanning with respect to an image forming surface, and a light beam. an optical member for forming an image on an image forming surface; a housing for accommodating the optical member and a deflection means; In an optical scanning device equipped with a synchronization detection device that outputs a synchronization signal for starting modulation, an input end of an optical fiber of the synchronization detection device and a condenser lens that focuses a light beam on the input end are attached to a holding member. An integral or fixed mounting part is provided on the housing for holding and attaching the holding member, and an elastic claw piece is provided on one of the mounting part and the holding member, and an engaging part that engages with the elastic claw piece on the other side. are formed integrally with each other so that the holding member can be removably engaged with and attached to the attachment portion of the housing.

[For production]

With the above configuration, even if the optical fiber is reliably fixed to the holding member and cannot be removed, the holding member can still perform optical scanning through push-fitting between the elastic claw piece and the engaging part. It can be attached and removably engaged with the housing of the device. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

3 and 4 are a plan view and a perspective view of essential parts of an optical scanning device 4 which is an embodiment of the present invention.

This optical scanning device 4 has an L
A D (laser diode) unit 10, a first cylinder lens 11 and a first mirror 12 attached near the center of the bottom surface.
An imaging lens 13, a rotary deflector 16 consisting of a disk-type motor 14 attached to the rear of the bottom, a polygon mirror 15 rotated in the direction of arrow A, a second mirror 17 attached to the front, and a second cylinder lens. 18, a third mirror 20 attached to the bottom side, a condensing lens 7 made of a cylinder lens attached to a side attachment 6, and a holding member 3 for holding the optical fiber 1.

The LD unit 10 includes a laser diode (hereinafter referred to as rLDJ) inside, a collimator lens that converts a diverging beam emitted from the LD into a parallel light beam, and a shape of the light beam that passes through the collimator lens in the scanning direction. In addition to integrally incorporating an aperture member that is shaped to be long and short in the sub-scanning direction, it also includes a printed circuit board 10a that forms part of an automatic output control circuit (APC) that controls the output of the LD. In addition. A monitoring photodiode that receives laser light emitted rearward from the LD is integrated into the LD.

The first cylinder lens 11 functions to shape the parallel light beam emitted from the LD unit 10 in the sub-scanning direction above the photoreceptor drum. The imaging lens 13 converts the parallel light beam reflected by the first mirror 12 into a convergent beam, and further refracts it diagonally upward by about 59 degrees to form a polygon mirror.
15 onto the mirror surface 15a.

The polygon mirror 15 is an R polygon mirror shaped by curved mirror surfaces 15a, and is a post-object type mirror that does not use the fθ lens that was conventionally placed between it and the second mirror 17 (the light beam is convergent light). The rotary deflector 16 is of the type in which a deflector is placed later. The second mirror 17 reflects the light beam (scanning beam) reflected and deflected by the rotary deflector 16 toward the photosensitive drum 19 . The scanning beam reflected by the second mirror 17 passes through the second cylinder lens 18 and is imaged as a sharp spot on the main scanning line 119a on the photosensitive drum 19.

Further, the third mirror 20 is disposed outside the scanning area on the photosensitive drum 19 by the light beam reflected by the rotary deflector 16, and reflects the incident light beam toward the optical fiber 1 side. The light beam reflected by the third mirror 20 and condensed by the condensing lens 7 onto the incident surface 1a of the optical fiber 1 is guided through the optical fiber 1 to a light receiving element consisting of a photodiode (not shown), and determines the scanning start position. It is converted into a synchronization signal to keep it constant. The synchronization detection device consists of these optical fibers 1, holding member 3,
It is composed of a condenser lens 7 and a light receiving element (not shown). In this optical scanning device 4. LD of LD unit 10
A laser beam modulated according to an image signal from a (laser diode) is collimated by an internal collimator lens and emitted as a parallel beam shaped by an aperture member. 1 mirror 1
After being reflected by the polygon mirror 1, it is converted into a convergent beam by the imaging lens 13 and refracted slightly upward.
The light is incident on the mirror surface 15a of No.5.

The convergent beam reflected by the mirror surface 15a of the polygon mirror 15 is further reflected by the second mirror 17, and is imaged as a spot on the photoreceptor drum via the second cylinder lens 18. . At this time, as the polygon mirror 15 rotates in the direction of arrow A, the imaged spot becomes a scanning spot that scans in the direction of arrow B (main scanning) on the main scanning line 19a above the photoconductor drum. , this scanning spot on the photoreceptor drum (main scan) is repeated for each mirror surface 15a of the polygon mirror 15, and at the same time, the photoreceptor drum 19 is moved in a direction perpendicular to the main scanning direction (sub-scanning direction). By rotating the photoreceptor drum, an electrostatic latent image corresponding to the image signal is formed on the photoreceptor drum. In addition, the scanning beam reflected by the polygon mirror 15 is
Before scanning above the photoreceptor drum, the light is reflected by the third mirror 20, enters the optical fiber 1 through the condenser lens 7, and is guided to the light receiving element, thereby controlling the scanning start timing.

In this way, this optical scanning device 4 emits a light beam from an oblique direction onto a line connecting the center position in the width direction of the photoreceptor and the rotation center of the polygon mirror, and then from there toward the rotation center of the polygon mirror. The light beam is reflected and refracted slightly upward so that it enters the mirror surface of the polygon mirror obliquely from below, and the light beam reflected by the polygon mirror is guided onto the photoreceptor through the mirror. In this case, the incident light and the reflected light do not intersect with each other in a so-called three-dimensional intersection with respect to the polygon mirror, so that it is possible to downsize the optical scanning device and improve writing accuracy.

1 and 2 are a cross-sectional view and a perspective view showing a first embodiment of the engaging portion between the holding member 3 and the mounting portion 6, and correspond to the conventional example shown in FIGS. 6 and 7. The same reference numerals are given to the corresponding parts.

Plug portion 2 of input end 2 including entrance surface 1a of optical fiber 1
A is fitted into the socket part 32 of the holding member B, which is made of an elastic or flexible material such as plastic, and whose entrance surface 1a is connected to the condenser lens 7.
The collar 33, which is partially cut out from the outside of the socket part 32, is caulked at a position (in the front-rear direction) that coincides with the focal point of the socket part 32, and is securely fixed. On the incident side of the holding member 3, a condensing lens 7 made of a cylindrical lens (sometimes a spherical lens) is elastically held by a pair of lens holding pieces 34 having a fitting groove.

In this way, the optical fiber 1 (incidence surface 1a) and the condensing lens 7 are each securely fixed to the holding member 3 and their relative positions do not move, so a considerable force is applied to the long cable portion of the optical fiber 1. The optical axis will not shift even if it is applied or twisted. Here, the condensing point of the condensing lens 7 is an optical convergence point, that is, an image point of the light beam reflection point on the mirror surface 15a of the polygon mirror 15 by the condensing lens 7. With this structure, even if optical path deviation occurs in the vertical (double scanning) direction due to the surface tilt of the mirror surface 15a, it is corrected.
The light can be reliably made to enter the entrance surface 1a of the optical fiber 1.

In order to prevent the entire holding member 3 from being installed at an angle with respect to the housing 5 of the optical scanning device 4 or its mounting portion 6, the holding member 3 has a flange portion 31 having a mounting surface 35 orthogonal to the optical axis.
A pair of elastic claws 36 and a position regulating plate 57 protrude from the mounting surface 35 of the collar 31, respectively.

On the other hand, the mounting portion 6 of the housing 5 of the optical scanning device 4 has holes 63 each having a pair of regulating grooves 61 and an engaging edge 62.
The mounting surface 64 is the outer surface of the housing 5.

When the holding member 3 is inserted into the mounting part 6, the position regulation plate 37 and the regulation groove 61 are fitted together to regulate the horizontal and vertical positions and inclination, and the mounting surface 35 and the mounting receiving surface 64 are brought into close contact with each other, so that the front and rear positions are adjusted. be regulated.

Further, the elastic claw piece 36 that has passed through the hole 63 while being bent opens, and the inner slope 36a of the elastic claw piece 36 and the engagement edge 62 which is the engagement part are elastically engaged, and the holding member 3 is attached to the mounting part. It is installed in the correct position relative to 6.

When removing the optical fiber 1 from the housing 5 of the optical scanning device 4, apply force to the support member 3 and pull it out, and the inner slope 5
8a is held by the engagement edge 62, and the elastic claw piece 36 can be removed by passing through the hole 63 while being bent.

FIG. 5 is a cross-sectional view showing a second embodiment of the engagement portion between the holding member 3 and the attachment part 6, and the parts corresponding to the first embodiment shown in FIGS. 1 and 2 are the same. A symbol is attached and the explanation is omitted. This second embodiment is different from the first embodiment in that the mounting part 6 is provided as a separate member fixed to the housing 5, and the elastic claw piece and its latching edge are attached to the mounting part 6 and the holding member 3. They are set in reverse order.

That is, in FIG. 5, the mounting part 6 is a separate member fixed to the housing 5 of the optical scanning device 4, and the mounting receiving surface 6 is made of an elastic or flexible material like the holding member 3.
4. The elastic claw piece 65 and a position regulating member (not shown) are integrally molded 4. On the other hand, the holding member 3 does not have an elastic claw piece, and a part of the flange 31 is attached to the elastic claw piece 65 of the mounting part 6. A locking edge 3, which is an engaging portion that engages with the inner slope 65a, is formed.

The structure and function of the holding member 3 holding and fixing the optical fiber 1 and the condensing lens 7, and the method and function of attaching and detaching the holding member 3 to the mounting portion 6 are the same as in the first embodiment, and their explanations are omitted. do.

In the above, in the first and second embodiments, the explanation has been given as an example of caulking using the partially cut-out collar 33 for fixing the optical fiber 1 to the holding member 3. Any method may be used as long as it is securely fixed to 1a, such as adhesive that cannot be reseparated. Further, although an optical scanning device using a rotating deflector using a polygon mirror has been described as an example, the optical scanning device is not limited to this.

By doing this, the optical fiber can be easily and removably engaged with the housing of the optical scanning device together with the holding member to which the optical fiber is securely fixed and can be securely attached.

〔Effect of the invention〕

As explained above, according to this invention, assembly is possible! ! Il
It is possible to provide an optical scanning device that has excellent workability during maintenance and repair, and that can provide stable synchronization timing even when force is applied to the optical fiber cable section.

[Brief explanation of drawings]

1 and 2 are a sectional view and a perspective view showing a first embodiment of an engaging portion of an optical fiber according to the present invention, FIG. 3 is a sectional view showing a second embodiment of the same, and FIGS. FIG. 5 is a plan view and a perspective view of essential parts of an embodiment of the optical scanning device, FIGS. 6 and 7 are a cross-sectional view and a perspective view of a conventional example of an engaging portion of an optical fiber, and FIG. FIG. 2 is an explanatory diagram showing the state of a light beam incident on an optical fiber. 1... Optical fiber 2... Input end 3...
- Holding member 4... Optical scanning device 5...
Housing 6...Mounting part 7...Condensing lens 16...Rotary deflector (deflection means) 38.85...Elastic claw piece 58.82...Latching edge (engaging part) 1 Fig. 3 Figure 4 Figure 1 z5 Figure b j! 8 Figure 16 Figure 7

Claims (1)

[Scope of Claims] 1. Deflection means for repeatedly deflecting a light beam modulated by an image signal at a constant angle to perform main scanning with respect to the image forming surface, and an optical system for focusing the light beam on the image forming surface. a housing for accommodating a member, an optical member thereof, and the deflection means; a housing for detecting the light beam deflected by the deflection means in a predetermined direction immediately before starting modulation via an optical fiber and generating a synchronization signal for starting modulation; An optical scanning device including an output synchronization detection device, wherein a holding member holds an input end of an optical fiber of the synchronization detection device and a condensing lens that focuses the light beam on the input end, and the holding member An integral or fixed mounting part is provided on the housing for mounting the housing, an elastic claw piece is provided on one of the mounting part and the holding member, and an engaging part that engages with the elastic claw piece is integrated on the other side. An optical scanning device characterized in that the holding member is detachably engaged with and attached to a mounting portion of the housing.