JPS59229549A - Variable power type copying machine - Google Patents

Abstract

PURPOSE:To correct the length of an optical path accurately and simplify the constitution of a copying machine by moving the 2nd mirror by a means which couples a movable support member for a projection lens moved according to variation in copy magnification with the 2nd mirror mechanically. CONSTITUTION:A wire 30 between a pulley 42 and the fixation point 36 of the lens support member 7 for the wire 30 is extended straight in unmagnification copying operation, and a correcting member exerts no influence upon the wire 30. The lens support member 7 is moved to left in enlargement copying operation, and the wire 30 comes into slide contact with the projection curved surface 38a of the correcting member 39a according to the extent of movement. In this case, the contour of the projection curved surface 38a corresponds to the amount of optical path correction necessary for the enlargement copying operation, so the extent of movement of the 2nd mirror is specified according to the variation in copy magnification, correcting the optical path lenght properly. The lens support member is moved to right in reduction copying operation and a correction is made as well as in the enlargement copying operation. Thus, the optical path length is corrected accurately through the simple constitution.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a variable magnification type copying machine capable of changing the copying magnification for enlarged copying and copying. The present invention relates to a variable magnification type copying machine in which copying magnification is changed by moving a disposed projection lens.

[Prior Art] In general, an exposure optical system of a variable magnification copying machine of a moving mirror type has a configuration as shown in principle in FIG. A first mirror M1 fixedly fixed on the first scanning member 4 together with a lamp 3 for illuminating the original surface is placed on the first scanning member 4 with respect to the surface 2 of the document placed on the transparent document mounting table 1. is provided to scan the document surface as it moves parallel to the document surface 2,
In order to optically couple the first mirror M1 to the projection lens L disposed in the optical path between the document surface 2 and the photosensitive surface 5 of the photosensitive drum D, the first mirror M1 and the projection lens L are connected.
A second mirror M consisting of two mirrors M2a, M, and h arranged at right angles to each other in the optical path between the
2 is fixed to a second scanning member 6, and this second scanning part shrine 6 is configured to move together with the second mirror M2 as the first scanning part paulownia 4 moves. .

In this case, when the moving distance of the first scanning member 4, that is, the moving distance of the first mirror M, is t, the second scanning section'
The material 6 moves the first scanning member 4 along with the second mirror M2 a distance of ``At'' at the speed of the rod equal to the moving speed of the first scanning member 4.
By moving in the same direction as the third mirror Ms, while keeping the optical path length between the document surface 2 and the projection lens L constant.
(fixed) to project the original Ω slit image onto the photosensitive aperture.

Furthermore, a fixed focus lens is generally used as the projection lens L, and in the case of full-size copying, the optical path length between the document surface 2 and the projection lens L and the optical path length between the projection lens L and the photosensitive surface 5 are as follows. When the focal length of the projection lens L is f, both are selected to be 2f, so the total path length is 4f. When changing the copying magnification, the lens support member 7 carrying the projection lens L is moved left and right in accordance with the change in the copying magnification prior to copying to perform enlarged or reduced copying.

Incidentally, in the variable magnification type copying machine as described above, it is necessary to correct the total path length between the document surface 2 and the photosensitive surface 5 in accordance with a change in the copying magnification. Now, the optical path length between the document surface 2 and the projection lens L is a1 The optical path length between the projection lens L and the photosensitive surface 5 is b1 The total optical path length is X, ? jfIf the magnification ratio is m, the total optical path length It is necessary to make a correction to extend the near f distance. For this reason, variable magnification copying machines have been proposed that are equipped with an optical path length correction device associated with a mirror moving mechanism, as shown in FIGS. 2 and 3, for example. ing.

In FIGS. 2 and 3, the first mirror M1 is fixed on the first scanning member 4 at an angle of 45° with respect to the document surface 2, and a run plate 3 for illuminating the document surface is placed beside it.
and a reflective shade 11 are attached respectively. One side of the first scanning section 4 is loosely inserted into the guide shaft 12, and a roller 14 that rolls on the guide shaft 13 is attached to the other side.

two mirrors M2a arranged at right angles to each other;
A second mirror M2 made of M2b is fixed.
One side of the scanning member 6 is also fitted into the guide shaft 12,
A roller 15 that rolls on the kite shaft is provided on the other side. A pulley 16 is rotatably supported on one side of the second scanning member 6, and an endless wire 16 is connected to the pulley 18→
Pulley 16 → Zo-ri 19 → Goo-ri 20
→A9-ri 16 →Pulley 21 →Guri 18 are stretched in this order, and the wire 17 is further connected to pulley 16 and pulley 2.
It is fixed to the first scanning member 4 at a point between 1 and 1, and is wound around the optical path length correction rotating shaft 22 between the pulley 19 and the pulley 20.

This rotating shaft 22 is normally kept in a fixed state, so when the pulley 18 is rotated clockwise by the motor 23, the first scanning member 4 is moved to the first position.
However, since the wire 17 is wrapped around the optical path length correction rotating shaft 22 and is fixed at the position of the rotating shaft 22, the pulley 16 moves according to the principle of a pulley. The second scanning member 6 is moved to the right while rotating clockwise, and the second scanning member 6 is moved together with the second mirror M2 at a speed of 40μ of the first scanning member.

Next, if the optical path length correction rotation shaft 22 is rotated clockwise in the same state without rotating the pulley 18, the first scanning member 4 will not move or the pulley 16 will rotate one rotation clockwise. Since the second scanning member 6 moves to the left together with the second mirror M2, the second scanning member 6 moves to the left while
and a second mirror M1. The distance between the M2 openings is widened, and therefore the optical path length is changed to become longer. Conventionally, the optical path length can be corrected by changing the optical path length by a sufficient amount corresponding to the change in the copying magnification. As shown in FIG. 3, a drive motor 26 is connected to the optical path length correction rotation shaft 22 via, for example, a gear shifter 24 and a cam mechanism 25, and the cam plate 27 is rotated by the motor 26. By this movement, the rotation shaft 22 is rotated clockwise in accordance with the change in copying magnification, thereby correcting the optical path length.

However, since the optical path length correction opening is non-linear with respect to the copying magnification m as described above, the design of the cam mechanism 25 is not easy, and when the enlargement and reduction magnifications are large, the optical path length correction Therefore, it was necessary to use a cam mechanism 25 with an amplification mechanism as shown in the figure, or to use a cam plate with a large diameter. Further, since a separate motor 26 was required to drive the cam mechanism 25, the mechanism for rotating the optical path length correction rotation shaft 22 became complicated and expensive. There were drawbacks.

In addition, conventionally, a drive mechanism has been proposed in which the rotation of the rotation shaft 22 is not driven by a motor, but uses a solenoid. Correction is not possible.

Furthermore, in variable magnification type copying machines, it is considered desirable to adjust the optical path lengths individually on both the magnification side and the spring and small sides due to variations in the focal length of the projection lens L. With conventional optical path length correction devices, it has been impossible to individually adjust the optical path length on the enlargement side and reduction side.

``Object of the Invention'' The present invention has been made in view of the above-mentioned points, and provides a variable magnification type copying machine equipped with an optical path length correction device that can accurately correct the optical path length when changing the magnification with an extremely simple configuration. The purpose is to provide.

The composition of the invention! Therefore, in the present invention, the lens support member supporting the projection lens L during zooming is centered at the position at the first copy of the same magnification.
Focusing on the movement B to the right in accordance with the copying magnification, means for mechanically coupling this lens support member to the second mirror M2, and movement of the second mirror M2 are controlled by the mechanical coupling means. Optical path long-sleeved formal attire consisting of a means of regulating in cooperation with
The f4J achieved the above objectives.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 4 and 5.

FIG. 4 shows a vertical portion of the optical path length correction device in the variable magnification type copying machine according to the present invention. In addition, in FIG. 4, overlapping parts with FIG. 3 are omitted, and FIGS.
Me with the figure 1 +? The same symbols are attached to V and minutes.

Also in FIG. 4, the wire 1 is attached to the rotation shaft 22 for optical path length correction.
7 is wound around it, and its rotation moves the pulley 16 to move the second mirror M2 independently of the first mirror M1, thereby changing the optical path length. In FIG. 4, a separate wire 30 having one end fixed to the pivot shaft 22 is wound around the pivot shaft 22, and the other end of the wire 30 is wound around the pivot shaft 22. is fixed at point 31 to the lens support member 7 carrying the projection lens L. Like the conventional one, the lens support member 7 is fitted onto the kite shaft 32 and fixed at a point 36 to an endless wire 35 stretched between pulleys 33 and 34H. (By rotation of the motor 37 in the clockwise or counterclockwise direction, the lens support member 7 is moved left and right together with the projection lens L, and the copying magnification is changed.

As will be clearer from FIGS. 5A to 5C, above the lens support member 7, there is a wire that passes through the fixing point 31 of the wire 30 to the lens support member 7 during full-size copying and is perpendicular to the guide shaft 32. A pair of correction portions U'39a and 39b are provided, each having convex curved surfaces 38a and 38b having a predetermined contour shape and facing each other across a plane, and the upper ends of these convex curved surfaces 38a and 38b facing each other , both correction members 39a and 39b have an extremely narrow gap 4.
The correcting members 39a and 39b face each other with an angle of .degree. between them, and the distance between the correcting members 39a and 39b increases continuously toward the bottom. Both correction parts 39a and 39b are supported by shafts 41a and 41b, respectively, in the vicinity of the gap 40, and can be rotated by a slight angle around 111141a and 41b during adjustment.

A wire 30 whose one end is fixed to the optical path length correction rotation shaft 22
first extends over the goo 942 to reach above the gap 4o, then extends downward through the gap 40, and has its other end fixed to the lens support member 7 at a point 31. A torsion spring 43 is wound around the one-way moving shaft 22 to bias the rotating shaft 22 counterclockwise to keep the wire 30 under tension at all times.

Lens support member 7 and correction member 39a during same-size copying
, 39b and the wire 30 are shown in FIG.
Therefore, the correction members 39a and 39b are in a state where they do not substantially affect the wire 30.

FIG. 5B shows the relationship between each component during enlarged copying, and as the lens support member 7 is moved to the left, the wire 30 is moved to the convex curved surface 38a of the correction member 39a in accordance with the movement i1JS=. The length of contact of the wire 30 with the convex curved surface 38a increases continuously as the lens support member 7 moves leftward. Therefore, the rotation 1i 1122 is pulled by the wire 30 and rotated clockwise, but the correction member 39
The contour of the convex curved surface 38a of a is necessary for enlarged copying) 1;
By compensating the path length, the convex curved surface 38a regulates the amount of movement of the rotary cover of the rotary shaft 22, and thus the second mirror M2, so that it can be changed in accordance with the change in copying magnification, and the desired optical path is adjusted. Long correction can be achieved.

FIG. 5C shows the relationship between each component during reduction copying. In this case, as the lens support member 7 is moved to the right, the wire 30 is moved to the correction section, Ifl' 39b, according to the amount of movement. It is clear that the rotary shaft 22 is brought into sliding contact with the convex curved surface 38b of the lens support member 7, and the rotating shaft 22 is rotated clockwise corresponding to the amount of movement of the lens support member 7, as in the case of an enlarged object.

Since the contour of the convex curved surface 38b of the correction member 39b is out of shape after reduction, the amount of movement of the second mirror M2 is regulated to be changed in accordance with the change in the copying magnification, and the desired θF is Optical path length correction can be achieved. Therefore, variations in the focal length of the projection lens L are corrected by the correction unit 39a.

39b to lN] by slightly rotating it around 41a and 41b.

"Effects of the Invention" As explained above, according to the present invention, the movement of the second mirror M2 for optical path length correction required when changing the copying magnification is moved in accordance with the change in the object magnification. Since the movable support portion of the projection lens L is moved by means of mechanically connecting it to the second mirror M11, it is not necessary to separately provide a special drive means as in the case of the optical path length correction device in a conventional variable magnification type copying machine. There is no need to provide the optical path length correction device, and the cost of the copying machine can be reduced by simplifying the installation of the optical path length correction device.

/- Also, the movable lens support member 7, such as the correction members 39a and 39b in the embodiment shown in FIGS.
and the second mirror M2 in cooperation with the mechanical coupling means of the second mirror M2.
Since a correction means for regulating the movement of mirror M2 is provided,
Optical path length correction that requires non-linear correction can be performed accurately and continuously. Furthermore, by using independent correction means for the enlargement side and the reduction side, the design of the optical path length correction device becomes easy, and adjustment for variations in the focal length of the projection lens L becomes extremely easy. It has advantages.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the principle of the exposure optical system in a mirror-moving double-magnification type copying machine, FIG. 3 is a perspective view of the device in No. 2131, FIG. 4 is a perspective view of the main part of the optical path length correction device in the variable magnification type copying machine VC according to the present invention, and FIGS. 5A to C are the device in FIG. 4. FIG. 4 is an explanatory diagram showing the state LIA at the time of equal-size tL copying, enlargement reproduction, and reduction copying. Ml...first mirror, M2...second mirror, L
...projection lens, D...photosensitive drum, 1...document mounting table, 2...document surface, 4...first scanning section cover,
5... Photosensitive surface, 6... Second scanning section, 7... Lens support member, 16... Moving pulley, 17... Wire, 22... Rotating shaft for optical path length correction , 30... Wire, 31... Wire fixing point, 38 a, 38 b-
Convex curved surface, 39 a, 39 b ・= correction member, 40
...Gap, 41a, 41b...Shaft, 42...Boo'1, 43...Torsion streak ring. ■゛1 (Method) Commissioner of the Patent Office 1, thing! Indication of i 1988 Special Patent F [i No. 91129 (j 2, Name of the invention: Variable-magnification type copying machine 3, Person making the amendment I! Relationship with 1: Patent applicant Fuji U-Rocks Co., Ltd. 4, Agent ( 104) Gin PL', Chuo-ku, Tokyo = 2-11-2
No. August 10, 1981 [1 (Shipping date: August 30, 1982)

Claims (1)

[Claims] A first mirror for scanning the document surface, a second mirror optically coupled to the first mirror, and a projection lens are disposed in the optical path between the document surface and the photosensitive member, and the copying magnification is In the variable magnification type copying machine, the projection lens is moved in accordance with the change in the projection lens so that the second mirror is moved in accordance with the movement of the projection lens.
means for mechanically connecting the second mirror to the second mirror, and correction for regulating movement of the second mirror in cooperation with the second mirror so as to change the length of the optical path in accordance with changes in the copying magnification. A variable magnification type copying machine characterized by being equipped with a path length correction device (consisting of means).