JPS59139027A - Copying device - Google Patents

Abstract

PURPOSE:To perform exactly end face matching on a photosensitive drum without moving an imaging lens by providing a pair of parallel plane mirrors between the imaging lens and the photosensitive drum and rotating simultaneously the mirrors according to a variable power thereby varying the spacing between the same. CONSTITUTION:Mirrors 11, 12 for end face matching are provided between an imaging lens and a photosensitive drum. Members 13, 14 of a top plate and a bottom plate are freely slidably superposed. The mirror 11 is attached to the member 13 and two linear grooves 16a, 16b are provided. Two arc groove 15a, 15b are formed to the member 14, and pins 17a, 17b are inserted at the crossed points of both grooves. The mirror 12 is provided inclinedly to said pins. The mirrors 11, 12 are therefore rotated in parallel by moving a lever 20 in an arrow A or B direction, by which the spacing therebetween is adjusted. The end face matching to match the end part of an original with the home position of the drum is thus exactly accomplished without moving the zoom lens in the stage of variable magnification.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying apparatus having a variable magnification function.

In a copying machine, the following several methods can be considered as ways to use the zoom lens' for changing the magnification.

(1) A method in which the distance between the object and image is kept constant and only the zoom lens is moved to change the magnification.

(2) A method in which the distance between the object and the lens is kept constant and the distance between the zoom lens and the image is changed without moving the zoom lens to change the magnification.

(3) A method in which the distance between the zoom lens and the image is kept constant and the distance between the object and the zoom lens is varied without moving the zoom lens to change the magnification.

The present invention utilizes the method (2), particularly (2).
) The advantages of the method are that the distribution of the illumination light source remains constant, that the magnification can be changed by moving a light mirror without moving a heavy zoom lens, and that the scanning mirror is always constant. One example is that it is sufficient to move l/X to l,N.

However, in a copying apparatus that takes advantage of this advantage, end face alignment becomes a problem. When an original image of a size of It is necessary to ensure that the end position of the document image of J- is always at the reference position, and this is called end face alignment.

Even with method (2) mentioned above, it is necessary to move the zoom lens laterally to align the end faces, but as a method for aligning the end faces with the zoom lens completely fixed,
As disclosed in Japanese Patent Application Laid-Open No. 52-154041,
It is known that a pair of parallel plane mirrors is provided between a zoom lens and a photoreceptor, and the optical axis is displaced by rotating these mirrors.

For example, FIG. 1 shows an optical system using this method, and this method will be explained below. In Fig. 1, 1 is a plantain glass plate, 2.3.4.5.6.7 are the first, second, third, fourth, fifth, and sixth mirrors, respectively, and the third mirror is 4. Zoom lens 8 between the fourth mirror 5
is interposed, and a photosensitive tram 9 is disposed below the sixth mirror 7. Here, the J, second, and third mirrors 2
．． 3.4 is used for document platen scanning, and the first mirror 2
scans the document table at a speed of V, the second and third mirrors 3
．． 4 as one body follows the first mirror 2 at a speed of v/2, and the optical path length between the glass plate 1 and the zoom lens 8 is corrected so that it is always constant. The first mirror 2 is a glass plate 1
The second mirror 3 forms an angle of 45 degrees with respect to the glass plate 1.
Similarly, if the angle is set at 45 degrees, and the second mirror 3 and the third mirror 4 are set at 90 degrees, the optical axis of the zoom lens 8 becomes parallel to the glass plate 1. The position of the zoom lens 8 having a variable focus function is fixed, and the focal length can be changed by moving an internal lens or changing the focal length by using an additional lens.

The focal length of the zoom lens 8 is changed by the amount of displacement that can achieve each magnification change when the distance between the document surface of the glass plate 1 and the center of the zoom lens 8 is fixed. That is, assuming that the distance #a between the document surface and the zoom lens 8 is constant (for simplicity, we assume that there is no movement of the principal point), the focal length #f is determined by the magnification β, as follows: f=βa/(1+β) Displaced to. As a result, the distance between the document surface and the zoom lens 8 (the principal point may fluctuate, but this is negligibly small) becomes approximately constant, and the angle used by the zoom lens 8 itself at each magnification change is determined.

At this time, as a matter of course, when changing the magnification, it is necessary to change the distance between the zoom lens 8 and the photosensitive drum 9 according to the displacement of the focal length #f corresponding to reduction/enlargement. There are many known methods for displacing the distance, such as a method (not shown) in which a plurality of movable mirrors are inserted between the zoom lens 8 and the fourth mirror 5, or between the fourth mirror 5 and the fifth mirror 6. . Further, the fourth mirror 5 is arranged at an angle of 45 degrees with respect to the optical axis, and the fifth mirror 6 is arranged at an angle of 9 degrees with respect to the fourth mirror 5.
It is considered to be an angle of 0 degrees.

Here, in order to align the end faces, the fifth mirror 6 and the sixth mirror 7 are parallel plane mirrors, and while maintaining the parallelism of these mirrors 6 and 7, they are moved to the fifth mirror as shown in FIG.
What is necessary is to rotate the light incident on the mirror 6 around the optical axis.

In this case, if the fifth and sixth mirrors 6.7 are in the digits indicated by solid lines, the light rays incident on the surface of the fifth mirror 6 at an angle of 45 degrees will be reflected by the fifth mirror 6. Later, ray L2
This is further reflected by the sixth mirror 7 and the photoreceptor drum 9
It will be incident on the end face E of. Next, in order to align the end faces, the fifth and sixth mirrors 6.7 are rotated by an angle of 0 around the optical axis of the light beam L1 while maintaining their mutual relationship. 5th. The position of the sixth mirror 6.7 is indicated by a broken line. In this case, the ray L
After being reflected by the fifth mirror 6, the light beam L3 is rotated by an angle of 20, becomes a reflected light beam L3, is reflected by the sixth mirror 7, and enters the photoreceptor drum 9. At this time, the position of incidence on the photoreceptor drum 9 is off the end surface E, and this deviation amount d is at a rotation angle of 0.
increases in proportion to. In other words, although it is possible to achieve a level of end face alignment by rotating the fifth and sixth mirrors 6.7, which are parallel plane mirrors, the end face alignment is still approximate and does not result in accurate end face alignment.

An object of the present invention is to provide a copying apparatus that eliminates the above-mentioned drawbacks of the parallel plane mirror and realizes accurate end face alignment. An end face alignment mechanism consisting of two parallel plane mirrors is inserted between them, and 1 nucleus 9; 1! The surface alignment mechanism is characterized by a mechanism that rotates these mirrors while maintaining parallelism and changes the gap between these mirrors in accordance with the magnification change by the imaging optical lens. be.

Next, the present invention will be explained in detail based on the embodiment shown in FIGS. 3 and 4.

In FIG. 3, mirrors 11.12 have the same function as the fifth and sixth mirrors 6.7, and for convenience of explanation, they are shown in a different viewing direction from FIG. 2. . Note that the optical system and photosensitive drum for the light beam L1 to reach these mirrors 11 and 12 are omitted from illustration because they can be considered in the same way as in FIG. 1 and pose no problem.

The mirror 11 is inclined at an angle of 45 degrees to the upper plate member 13-4, and the upper plate member 13 is slidably superposed on the lower plate member 14''. Two arcuate grooves 15a, 15b centered on the optical axis of the light beam L1 are formed in the lower plate M material 14, and further, these arcuate grooves 15a, 15b are formed in the plate member 13.
Two straight grooves 16a and 16b intersect with 5b,
It is provided in a direction perpendicular to the direction in which the mirror J1 is arranged. These arcuate grooves 15a, 15b and straight grooves 16a, 16
Pins 17a and 17b are inserted through the intersections of b, respectively, and the upper plate member 13 transmits the light beam L1 to the lower plate member 14.
The mirror 11 can move in an arc shape centered on the optical axis of the mirror 11, and can also move linearly in a direction perpendicular to the mirror 11. Furthermore, the mirrors 12 are tilted at an angle of 45 degrees on the pins 17a and 17bJ, parallel to the mirror 11, so that the distance between the mirrors 11 and 12 is variable. Further, a rectangular hole 18 is opened between the mirrors 11 and 12 of the upper plate member 3, and a fan-shaped hole 19 is opened in the lower plate member 14.
The rays of light reflected by can pass downward.

Note that 20 is a lever for operating the upper plate member 13 relative to the lower plate member 14.

Since the embodiment according to the present invention has the above-described configuration, when aligning the end faces, the lever 2o is moved in the direction of arrow A to rotate the mirrors 11, 12 about the optical axis of the light beam Ll while maintaining parallelism. Further, the deviation sensitivity d for the end face E shown in FIG. 2 can be corrected by moving the lever 20 in the direction of arrow B and adjusting the distance between the mirrors 11 and 12. Note that the optimum position for the movement of the lever 2o must be determined in advance according to the stage of zooming. As a result, even when the zoom lens is used to change the magnification, the light beam L1 is sequentially reflected by the mirror 11 and the mirror 12, and the rectangular hole 8,
It reaches the end surface E of the photosensitive drum through the fan-shaped hole 19.

It goes without saying that the present invention is not limited to the embodiments described above, and that many modifications can be made within the scope of the claims.

As explained above, according to the copying apparatus according to the present invention, a pair of parallel plane mirrors are distributed between the imaging optical lens and the photoreceptor drum, and the mirrors rotate together, and the interval between them is variable. Therefore, even if the imaging optical lens is changed in magnification, the end faces on the photoreceptor tram can be accurately aligned without moving the imaging optical lens at all.

[Brief explanation of the drawing]

FIG. 1 is an optical configuration diagram of a conventional copying apparatus, FIG. 2 is a functional explanatory diagram of a conventional parallel plane mirror, FIGS. 3 and 4 show an embodiment of a copying apparatus according to the present invention, and FIG. 3 is a perspective view of the parallel plane mirror, and FIG. 4 is a plan view of the upper plate member. 1 is a glass plate, 2 to 7, 11 and 12 are mirrors, 8 is a zoom lens, 9 is a photosensitive drum, 13 is an upper plate member, 1
4 is a lower plate member, 15a, 15b are arcuate grooves, 16a, 16
b is a straight groove, 17a and 17b are pins, 18 is a rectangular hole, 1
9 is a fan-shaped hole and 2° is a lever. Figure 1 Figure 3 Figure 4 132

Claims (1)

[Claims] 1. An end face alignment mechanism consisting of two parallel plane mirrors is inserted between an imaging optical lens having a variable magnification function and a photoreceptor, and the end face alignment mechanism 1. A copying apparatus characterized by having a mechanism that rotates these mirrors while maintaining parallelism and changes an interval between these mirrors in response to a change in magnification. 2. The operation of the end face alignment mechanism is such that one mirror is fixed to the upper plate of two stacked slidable plates, and two circular arc grooves provided on one plate and two circular grooves provided on the other plate are used. intersect each of the straight grooves, insert a pin into each intersection,
2. The copying apparatus according to claim 1, wherein the copying apparatus is configured to perform this by fixing a self-powering mirror on the pin.