JPH04171435A - Lens unit holding mechanism for optical system - Google Patents

Abstract

PURPOSE:To simplify the adjustment of optical path length and the balance adjustment of resolving power by fitting a lens unit to a lens unit fitting member in such a way that its angle can be changed into the rotating axis direction of a sensitized body, around an axis orthogonal to an optical axis in the vicinity of the principal point of the lens unit. CONSTITUTION:A lens unit fitting member 27 is provided at a base 26 on the device body side in such a way that its position can be changed into a document scanning direction (the optical axis direction of a lens unit 24), and the lens unit 24 is fitted to the lens unit fitting member 27 in such a way that its angle can be changed into the rotating axis direction of a sensitized body 4 to form lens unit holding mechanism 25. The adjustment of only the optical path length of the lens unit 24 and the balance adjustment of only the resolving power to the surface of the sensitized body 4 can be performed simply and exactly both in the desirable state of work performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens unit holding mechanism for an optical system that forms a latent image of an original on the surface of a photoreceptor.

[Conventional technology]

In order to adjust the optical path length and balance the resolving power in the direction of the rotation axis of the photoconductor, the lens unit that forms a latent image of the original image on the surface of the photoconductor is moved in the optical axis direction and the angle is adjusted in the direction of the rotation axis of the photoconductor. It is configured to be changeable.

Specifically, as shown in FIG.
Two screw holes j are formed on both sides of the upper surface of the case 32 with the optical axis interposed therebetween, and a long hole n is formed for inserting a screw m to be screwed into the screw hole j. It is formed on the lens unit cover 33 of the optical system with its long axis direction facing the optical axis direction of the lens unit 31, so that the movement of the lens unit 31 in the optical axis direction within the range of the elongated hole n causes the optical path. The resolving power balance is adjusted by adjusting the length and changing the angle of the lens unit 31 in the direction of the rotation axis of the photoreceptor based on the clearance between the long hole n and the screw m. I try to make it possible.

[Problem to be solved by the invention]

However, because of the configuration in which the movement of the lens unit 31 in the optical axis direction and the angle change in the rotation axis direction of the photoreceptor are performed simultaneously, it is necessary to adjust only the optical path length of the lens unit 31 or only the resolving power of the lens unit 31. It is very difficult to adjust the balance between the two, and it also causes the lens unit 31 to shift in position at the middle of the long hole n, which leads to a shift in the position of the latent image area on the surface of the photoreceptor. However, the workability of adjusting the optical path length and resolving power balance was very poor, and the work involved was enormous, which was particularly inconvenient in terms of mass production of image forming apparatuses equipped with the above-mentioned optical system. .

The present invention achieves the following through an extremely simple and rational improvement technique.
It is an object of the present invention to enable adjustment of optical path length and balance adjustment of resolution to be easily performed separately and with simple effort.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a lens unit holding mechanism for an optical system that latently images an image of a document on the surface of a photoreceptor, in which a lens unit mounting member is positioned in the optical axis direction with respect to a base on the apparatus main body side. The lens unit is attached to the lens unit attachment member so as to be freely changeable, and the lens unit is attached to the lens unit mounting member so as to be able to change the angle in the direction of the rotation axis of the photoreceptor around an axis perpendicular to the optical axis near the principal point of the lens unit. has.

[Effect]

According to the above characteristic structure, adjustment of only the optical path length of the lens unit and lens unit and balance adjustment of only the resolving power can be achieved separately.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an electrostatographic copying machine as an example of an image forming apparatus.
A photoreceptor 4 is mounted horizontally on a copying machine main body 3 which has a document table 1 and a document holder 2 on the top, and a charging device 5, a developing device 6, a transfer device 7, and a paper separation device 8 are installed around the photoreceptor 4. ,
A cleaning device 9 is disposed, and an exposure device 1O with a movable optical system is provided in the space below the document table 1.
A paper feed transport device 12 transports the paper in the cassette case 11 to the transfer device 7, a paper discharge transport device 14 transports the separated paper to the fixing device 13, and a paper discharge transport device 14 transports the paper after fixing to the tray 15. A pair of paper discharge rollers 16 are provided.

The optical system movable exposure device 10 includes a first optical traveling body 19 that includes a light source 17 that emits light onto the document on the document table 1 and a first mirror 18 that re-reflects the light reflected from the document table 1. , a second optical traveling body 22 including second and third mirrors 20.21 that twice reflects the light reflected from the first mirror 18 is provided so as to be movable back and forth in the document scanning direction; A fourth mirror 23 is provided to reflect the light reflected by the mirror 21 toward the surface of the photoreceptor, and the third mirror 23 is provided.
A lens unit 24 for imaging is provided in the optical path from the mirror 21 to the fourth mirror 23, and the first optical traveling body 19 is moved back and forth in the document scanning direction at twice the speed of the second optical traveling body 22. Drive of known configuration (not shown)
It consists of

The principal point P of the lens unit 24 is located at the midpoint of the optical path length from the document surface on the document table 1 to the photoreceptor surface, and the image of the document placed on the document table 1 is at the same magnification. The latent image is formed on the surface of the photoreceptor.

FIG. 1 shows a holding mechanism 25 for the lens unit 24. As also shown in FIGS. 3 and 4, this lens unit holding mechanism 25 is attached to a lens unit mounting member attached to a base 26 on the apparatus main body side. 27 is provided so as to be freely changeable in its position in the document scanning direction (the optical axis direction of the lens unit 24), and the angle of the lens unit 24 with respect to this lens unit mounting member 27 can be freely changed in the direction of the rotational axis of the photoreceptor 4. It is attached to.

More specifically, the lens unit mounting member 27 is a bent steel plate product, and forms two mounting plate portions 27a for the base 26 and a mounting plate portion 27b for the lens unit 24. forming a long hole a in the optical axis direction in each of the mounting plate portions 27a;
A screw hole C for screwing the screw b inserted into the long hole a is screwed into the base 26, and the width of the short diameter of the long hole a is larger than the outer diameter under the neck of the screw b. The mounting plate portion 27b is set slightly inward, and as the position of the lens unit attachment member 27 relative to the base 26 is changed, the mounting plate portion 27b
The lens unit 24 attached to the lens unit 24 is configured so that its position can be changed only in the optical axis direction.

On the other hand, on the lower surface of the case 28 of the lens unit 24,
A circular protrusion d around the axis P1 passing through the principal point P of the lens unit 24 and perpendicular to the optical axis is protruded, and a protrusion insertion hole e having a slightly larger diameter than the circular protrusion d is provided in the mounting plate. Two screw insertion holes f are formed in the part 27b and in the case 28 portions corresponding to both sides of the optical axis with the principal point P as the center, and the diameter of the screw insertion hole f is adjusted so that the hole is inserted into Set it to be larger than the outer diameter under the neck of screw h,
Further, a screw hole i for screwing the screw h inserted into the hole f is screwed into the mounting plate portion 27b, and the lens unit 24 is attached to the lens unit mounting member 27.
The angle can be changed around the principal point P only in the direction of the rotation axis of the photoreceptor 4.

In addition, in FIG. 3, 29 in the figure is a lens unit cover.

According to the above configuration, by changing the position of the lens unit mounting member 27 in the optical axis direction, the original platen 1
Optical path length adjustment is achieved in which the principal point P of the lens unit 24 is positioned at the midpoint of the optical path length from the upper document surface to the photoreceptor surface.

On the other hand, by changing the angle of the lens unit 24 around the principal point P in the direction of the rotation axis of the photoreceptor 4, balance adjustment of the resolving power on both sides of the photoreceptor surface in the rotation axis direction can be achieved.

In other words, only the optical path length of the lens unit 24 and the resolving power balance adjustment for the photoreceptor surface can be adjusted separately. For example, by adjusting the resolving power balance after adjusting the optical path length, the original image can be exposed to light. The body surface can be imaged exactly at the same magnification.

In the embodiments, the target image is one in which the image of the original is imaged at the same magnification on the surface of the photoreceptor. Alternatively, the present invention may be applied to an optical system in the form of a variable magnification latent image in which the lens unit 24 has a zoom function.

〔Effect of the invention〕

As explained above, the lens unit holding mechanism of the optical system according to the present invention has the function of moving the lens unit only in the optical axis direction and the function of changing the angle only in the direction of the rotation axis of the photoreceptor, respectively. This makes it possible to easily and precisely balance only the optical path length of the lens unit and the resolving power on the surface of the photoreceptor, while also adjusting the latent image area on the surface of the photoreceptor. Misalignment can now be avoided, and as a whole, it has become possible to provide a lens unit holding mechanism that is convenient, especially in terms of mass production of image forming apparatuses equipped with optical systems.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a lens unit holding mechanism, and FIG. 2 is a vertical sectional side view of an electrostatic photocopier as an example of an image forming apparatus.
FIG. 3 is a perspective view showing the lens unit holding mechanism with the lens unit cover removed, and FIG. 4 is a sectional view of the lens unit holding mechanism. FIG. 5 is a perspective view of a conventional lens unit holding mechanism. 4...Photoconductor, 24...Lens unit, 26...
・Base, 27...Lens unit mounting member, P
...Main point, P. ...axis line. Applicant: Sanda Kogyo Co., Ltd. Representative: Patent Attorney: Hideo Fujimoto 24...Lens unit 27...Lens unit mounting member P...Principal point Pl...Axis line in Figure 1 Oni 24...Lens unit 26... ... Base 27 ... Lens unit mounting member P ... Upper point Pl Axis line Fig. 4 Fig. 5

Claims (1)

[Claims] This is a lens unit holding mechanism for an optical system that latently images an image of a document on the surface of a photoreceptor, in which a lens unit mounting member is provided with respect to a base on the apparatus main body side so that its position can be freely changed in the optical axis direction, and the lens unit is mounted. A lens unit holding mechanism for an optical system, characterized in that a lens unit is attached to a member in the vicinity of the principal point of the lens unit so that the angle can be freely changed in the direction of the rotational axis of a photoreceptor around an axis perpendicular to the optical axis. .