JP2938175B2 - Optical writing device - Google Patents

Description

The present invention can be applied to an electrophotographic apparatus that performs recording on a recording medium by an electrophotographic method, such as a printer and a copier facsimile using a laser. More specifically, in such an electrophotographic apparatus, an optical writing device that deflects a laser beam from a laser light source with a deflector to scan on a photoconductor through an anamorphic imaging lens and writes on the photoconductor. About.

2. Description of the Related Art In an optical system such as an optical writing device having a plurality of anamorphic imaging lenses, it is very important to make the generatrix of the imaging lenses parallel. In particular, when the dot density is high, the displacement of the generatrix of the imaging lens significantly affects the change in the beam diameter. Therefore, conventionally,
In this type of optical writing device, a portion where a lens is provided when forming a housing is manufactured with strict dimensional tolerances, and the lens is directly mounted on the housing.

Problems to be Solved by the Invention However, in addition to variations in the dimensions of components such as lenses, and the recent increase in the dot density of optical writing, when the housing is manufactured, the dimensions of the imaging lens mounting part are reduced. It is becoming difficult to manufacture a lens installation part that does not affect the beam diameter by simply increasing the accuracy, and to mount the imaging lens so that the generatrix of the imaging lens is parallel. There was a problem.

For this reason, there has been a configuration in which the imaging lens is supported by an elastic body, and the imaging lens is moved by a screw in the sub-scanning direction against the elastic body so that fine adjustment can be easily performed.

Problems to be Solved by the Invention However, when the imaging lens is supported by an elastic body, there is a problem that, when a long time elapses, a slight shift occurs in the parallelism of the generatrix due to deterioration of the elastic body.

Therefore, an object of the present invention is to prevent the parallelism of the generatrix of the imaging lens from being deviated even after a long time elapses.

Means for Solving the Problems Therefore, the present invention deflects a laser beam L from a laser light source 30 with a deflector 33 to form an anamorphic imaging lens 34.
In the optical writing device 17 for scanning the photosensitive member 15 via 35 and writing on the photosensitive member 15, the imaging lens 35
Is supported by an elastic body such as a coil spring 48 via a support table 49, and an adjusting mechanism using an adjusting screw 50 or the like for moving and adjusting the imaging lens 35 in the sub-scanning direction against the elastic body. And a fixing means for fixing the position of the support table after the adjustment by the adjusting mechanism, for example, using a set screw 54 or the like.

Operation Then, the imaging lens 35 is supported by an elastic body via the support table 49, and the adjusting mechanism is adjusted so that the generatrix becomes parallel, and then the support table 49 is fixed by the fixing means.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 shows a laser printer shown as an example of an electrophotographic apparatus, and shows an overall schematic configuration of an internal mechanism thereof. Symbols in the figure
Reference numeral 10 denotes an apparatus main body. A paper cassette 11 is detachably attached to the right side of the apparatus main body 10 in the drawing. Paper cassette 11
Inside, paper 12 as a recording medium is stacked and stored. The paper 12 is sent out in the direction of arrow A by a paper feed roller 13, guided by a guide plate or the like, conveyed, and the leading end is made up of a pair of registration rollers
Press between 4.14 and stop there. And
A drum-shaped photoconductor 15 serving as an image carrier at a predetermined timing
Send out to.

The photoconductor 15 is driven by a driving device (not shown),
Rotate clockwise in the figure. At that time, the surface is uniformly charged by the charging charger 16, and then the surface is irradiated with laser light L from the optical writing device 17 according to the present invention to form an electrostatic latent image thereon. Thereafter, when passing through the position of the developing device 18, the toner is adhered by the developing device 18 and the electrostatic latent image is visualized. The visible image is transferred by the transfer charger 19 to the sheet 12 sent to the photoconductor 15 at a predetermined timing as described above. The image-transferred sheet 12 is conveyed to a fixing device 20, where it is fixed by applying heat and pressure thereto, and then sequentially discharged through a sheet conveying path 21 to a sheet discharge section 22 in the direction of arrow B.

On the other hand, the photosensitive member 15 after the transfer of the visible image
The residual toner is removed by the cleaning blade 24, and then the charge is further removed by the charge removing brush 25. The toner removed from the photoconductor 15 is sent into a collection tank 27 by a collection roller 26 and collected there.

Incidentally, in the optical writing device 17, specifically, as shown in FIG. 2, a laser beam L emitted from a laser light source 30 such as a laser diode is converted into a parallel beam by a collimating lens 31, and the first cylindrical lens 32 After that, the light enters the mirror surface of the deflector 33 rotating at a constant high speed. The reflected light deflects a predetermined angle range for each surface by rotating the mirror surface, and repeatedly scans the same angle range repeatedly. This laser light passes through long anamorphic imaging lenses 34 and 35, is reflected in a predetermined direction by a mirror 36,
An image is formed on the photoconductor 15 through a second cylindrical lens, that is, a similarly long cylindrical lens 37. The cylindrical lens 37 corrects an optical path shift due to the tilt of each mirror surface of the deflector 33.

The optical writing device 17 is housed in a box-shaped housing, and the imaging lenses 34 and 35 are attached as described below. In FIG. 1, reference numeral 40 denotes a lens cell provided in the housing. Imaging lens on lens cell 40
Positioning projection 41 holding both ends of 34 and 35
・ 41 and 42 ・ 42 are provided. And, for example, lens receiving portions 43, 43 are provided between the protrusions 41, 41 for one lens 34,
Blind holes 44 are provided between the projections 42 for the other lens 35. A screw hole 45 formed in the end face of the lens cell 40 communicates with the blind hole 44.

Then, first, the lens 34 is placed on the lens receiving portions 43, 43 and both ends are held between the protruding portions 41, 41 for positioning.
A holding plate 46 with a is mounted on the protrusion 41 with a set screw 47, and a leaf spring 4
Press and fix the lens 34 with 6a and 46a.

Next, one end of the coil spring 48 is inserted and the other end of the coil spring 48 protrudes from one end.
From the projecting side of the coil spring 48 into the blind hole 44. A flat portion 49a having a constant width over the entire length of the support base 49 is provided on a part of the peripheral surface of the support base 49. And support 4
9 with its upper surface protruding from the blind hole 44 with its flat portion 49a facing the screw hole 45, the other lens 35 is placed on the support 49, 49, and both ends of the lens 35 are placed between the protrusions 42, 42. Hold and position. Next, a holding plate 52 in which an adjusting screw 50 is screwed into a screw hole 51 provided on the plate surface is mounted on the projection 42 with a set screw 53. Then, the lens 35 is supported by the coil spring 48 via the support base 49 and is pressed against the adjusting screw 50.

Then, after adjusting the movement of the lens 35 in the sub-scanning direction orthogonal to the main scanning direction by twisting the adjusting screw 50 against the coil spring 48, the generatrix of the lens 35 is made parallel to the generatrix of the lens 34. The rotation of the adjusting screw 50 is stopped with an adhesive or the like. Then, a set screw 54 is inserted into the screw hole 45 provided in the lens cell 40.
And press it against the flat part 49a of the support
Is fixed. The set screw 54 is stopped by an adhesive or the like.
Accordingly, since the support base 49 of the lens 35 is fixed by the adjusting screw 50 with its generatrix parallel to the generatrix of the lens 34, there is no influence from the temporal change of the coil spring 48.

Effect of the Invention As described above, the present invention supports a lens with an elastic body via a support, and fixes the position of the support after adjusting the generatrix position of the lens, so that fine adjustment is possible. ,
Since the lens is finally fixed by the support stand irrespective of the elastic body, the lens is not affected by the change with time of the elastic body, and the bus parallelism of the imaging lens is maintained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of an optical writing apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing a schematic configuration of the optical writing apparatus, and FIG. 3 is equipped with the optical writing apparatus. FIG. 2 is a schematic configuration diagram of a laser printer. 15 photoconductor, 30 laser light source, 33 deflector, 34
35 ... imaging lens, 48 ... coil spring (elastic body), 50 ...
... Adjustment screw, 54 ... Set screw.

Claims (1)

(57) [Claims] 1. An optical writing apparatus for deflecting a laser beam from a laser light source by a deflector to scan on a photoconductor through an anamorphic imaging lens and to write on the photoconductor, wherein the imaging lens Is supported by an elastic body via a support base,
An optical writing device comprising: an adjustment mechanism for moving and adjusting the imaging lens in the sub-scanning direction against the elastic body; and fixing means for fixing the position of the support table after adjustment by the adjustment mechanism.