JPH0518087B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable magnification device for a copying machine such as an electrophotographic copying machine.

[Conventional technology]

2. Description of the Related Art There is a copying machine capable of variable magnification, in which an imaging lens is arranged so that its optical axis is oblique to a beam of light reflected from a document surface. When using an in-mirror lens as an imaging lens, the above arrangement is inevitable due to its structure, but even when using a through lens, the same arrangement is required to ensure the optical path length is as long as possible within the scope of compactness. is often arranged.

However, when the imaging lens is arranged as described above, simply moving the lens in the optical axis direction during zooming does not allow the imaging lens to accurately capture the beam of light reflected from the document surface. The reason for this is clear from what is shown in FIG. This figure shows the case of a through lens to simplify the explanation. In the figure, a is an imaging lens, b is an original surface, and c is a photoreceptor surface. Lens a is at the position (solid line) where it captures the beam d of reflected light from document surface b when it is at the same magnification, but moves to the position where it captures the beam d' of reflected light from document surface b' (dotted line) when the magnification is changed. This is necessary. Therefore, in order to move the lens a from the same magnification position to the variable magnification position or from one variable magnification position to another variable magnification position, it is necessary to simultaneously move the lens along the optical axis e in the vertical direction. It becomes necessary.

Of course, if the angle between the beam of light reflected from the document surface and the optical axis of the lens is kept constant each time the magnification is changed, it is possible to say that the lens only needs to be moved in the direction of the beam. There have been problems in that the positional relationship between the original surface and the photoreceptor surface changes each time the magnification is changed, resulting in variable magnification copying with degraded performance, and the control of the positional relationship between the original surface and the photoreceptor surface becoming complicated.

As a means to solve this problem,
Publication No. 57-173862 and Japanese Utility Model Application No. 57-169772 were published. Of these, the former is a distal ring portion of a lens frame in which the imaging lens is rotatably supported on the outer periphery of a bearing tube whose base end is slidable on a guide rail and supported in a non-rotating state. Moreover, since the distal end ring part into which the imaging lens was fitted was in sliding contact with the inclined cam, the lens frame had two parts: the proximal end and the bearing cylinder, and the bearing cylinder and the guide rail. Because it has a bearing part, play is likely to occur, and when moving in the direction of the optical axis of the lens, the tip ring part that makes sliding contact with the inclined cam will be delayed due to sliding contact resistance (first drawback), Since there is no guide in the direction in which the reflected light from the original is captured, there is a problem in that blurring is likely to occur (second drawback).

In addition, the latter has the imaging lens fitted into the central ring part provided in the lens frame supported between the guide rail and the curved cam, so it does not have a double bearing part like the former, and has the first drawback. However, it is true that there is no guide in the direction in which the reflected light from the document is captured, and the second drawback, that is, blurring when moving up and down, is unavoidable.

[Purpose and structure of the invention]

In view of the above points, the present invention arranges an imaging lens such that its optical axis is oblique to the beam of light reflected from the document surface, and moves the imaging lens in the direction of the optical axis of the lens and the direction of the document reflection when changing magnification. In a variable magnification device for a copying machine, which is movable in the direction of capturing light, the imaging lens is mounted on the front surface of a lens base plate that is integrated with a slide frame that can be moved in the direction of its optical axis, and is moved in the plane direction using a hinge pin as a fulcrum. The free end side of the movable plate is movably supported by an arc-shaped long hole and a fixed pin protruding from the surface of the lens base plate, which is loosely inserted into the long hole. When moving, the imaging lens stably moves in the direction of the optical axis of the lens, and eliminates blurring when moving in the direction of capturing the reflected light from the original, increasing accuracy. Furthermore, the lens remains stable at the position where the movement is completed. It is an object of the present invention to provide a variable magnification device for a copying machine that can easily maintain accuracy and maintain accuracy.

〔Example〕

Next, the present invention will be explained based on an embodiment shown in the drawings from FIG. 2 onwards.

Reference numeral 1 denotes a unit frame, and the unit frame 1 is reinforced by two parallel shafts 4 and 5 extending between the front and rear side plates 2 and 3 near both ends thereof. A shape slide frame 6 and a shape slide frame 7 are slidably fitted to one of the shafts 4 so that their groove sides are engaged with each other. Further, on the other shaft 5, the other end of the lens base plate 8 whose one end is fixed to the shaped slide frame 6 and the other end of the mirror frame 9 whose one end is fixed to the shaped slide frame 7 are attached to the roller 1.
0,11.

12 is a first mirror attached to a mirror frame 13 fixed to the rear of the unit frame 1; 14 is a second mirror attached to the rear surface of the mirror frame 9 that moves together with the shaped slide frame 7; 15 is the shaped slide A hinge pin 1 is attached to the front of the lens base plate 8 that is integrated with the frame 6.
This is an in-mirror lens attached to a movable plate 17 provided so as to be movable in the plane direction using 6 as a fulcrum. The free end side of the movable plate 17 is supported by a fixing pin 23 loosely inserted into an arc-shaped elongated hole 22.

The in-mirror lens 15 collects the reflected light from the document surface on the document platen glass surface (not shown) illuminated by a light source lamp (not shown) through the first mirror 12 and the second mirror 14. , a mirror frame 18 that reflects this and is fixed to the front part of the unit frame 1.
unit frame 1 via the third mirror 19 attached to
It is designed so that an image can be formed on a photoreceptor 21 through a through hole 20 provided in the bottom plate. The optical axis e of this in-mirror lens 15 is oblique to the luminous flux d of the reflected light from the document surface.

24 is a roller provided on the free end side of the movable plate 17 to which the in-mirror lens 15 is attached;
is in sliding contact with the curved cam 25, which is fixed to the bottom plate of the unit frame 1 so as to be parallel to the sliding direction of the slide frame 6, by its own weight. Therefore, when the slide frame 6 slides back and forth along the shaft 4 by the running of the wire 26 stretched between the two pulleys 27 and 27', the in-mirror lens 15 follows the curved surface of the curved cam 25. It moves in the vertical direction together with the movable plate 17, which moves up and down.

Reference numeral 28 denotes a spring member inserted so as to expand between the inner frames 6a and 7a of the slide frame 6 and slide frame 7, and the spring member 28 is a coil-shaped member fitted to the shaft 4. The shape slide frame 6 is pressed forward (rightward) and the shape slide frame 7 is pressed backward (leftward). Reference numeral 29 denotes an L-shaped lever rotatably attached to a suitable position on the sliding frame 6 via a shaft rod 30, and the horizontal arm 29a of the L-shaped lever 29 is installed on the bottom plate of the unit frame 1 via a roller 31 at its tip. The vertical arm 29b is in sliding contact with the cam surface of the second curved cam 32, and the vertical arm 29b has a protrusion 34 projecting from the slide frame 7 through its tip roller 33.
It abuts against the rear edge of the spring member 28 against the elastic force of the spring member 28. Therefore, when the slide frame 6 of the in-mirror lens 15 is pulled forward by the wire 26, the protrusion 34 is pushed by the tip roller 31 of the vertical arm 29b of the L-shaped lever 29, so that the second mirror 1
The slide frame 7 in the form of 4 is driven forward against the spring member 28. In this case, since the horizontal arm 29a of the L-shaped lever 29 is rotated counterclockwise by the second curved cam 32 during the movement process, the amount of movement of the shaped slide frame 7 is determined by the amount of rotation of the horizontal arm 29a of the L-shaped lever 29. 6
The amount of movement is smaller than the amount of movement. Also, when the shaped slide frame 6 slides backward from the reference point, the shaped slide frame 7 moves backward due to the elastic force of the spring member 28, but the L-shaped lever 29 moves back to the second curved surface in the backward movement process. The amount decreases by the amount of clockwise rotation by the cam 32. This is to effectively create a difference in the amount of movement required between the in-mirror lens 15 and the second mirror 14 during zooming, since the amount of movement required is different.

Next, the operation of the above embodiment will be explained.

An in-mirror lens 15 and a slide frame are attached via a movable plate 17 to a lever base plate 8 that moves integrally with a slide frame 6 that slides along the shafts 4 and 5 provided between the front and rear side plates of the unit frame 1. The initial position of the second mirror 14 attached to the mirror frame 9, which is movable together with the mirror 7, is set to the same-size copying position, and moves forward or backward from the initial position when changing the magnification. When the copy start button is pressed with the in-mirror lens 15 and the second mirror 14 at the initial positions described above, the document table glass moves together with the document, and the reflected light emitted from the light source lamp and reflected from the document surface is generated. are the first mirror 12 and the second mirror 1
4. The image is formed on the photoreceptor 21 through the in-mirror lens 15 and the third mirror 19. In this case, the roller 24 provided at the free end of the movable plate 17 to which the in-mirror lens 15 is attached is located approximately at the midpoint of the curved cam 25 with which it slides, and directs the luminous flux d of the reflected light onto the optical axis e.
It is viewed obliquely.

Next, when performing variable magnification copying, press the setting button to specify the magnification, and the drive motor is driven to slide the shaped slide frame 6 along the shafts 4 and 5, and the lens base plate integrated with it is driven. 8 and the lens base plate 8
Since the in-mirror lens 15 attached via the movable plate 17 moves in the direction of its optical axis according to the magnification ratio, the movable plate 17 slides against the curved cam 25 via the rollers 24 during this movement. It then moves up and down. When the copy start button is pressed after the in-mirror lens 15 moves in the optical axis direction and the vertical slide frame 6, the document table glass moves together with the document, and the luminous flux of reflected light emitted from the light source lamp and reflected from the document surface. d is accurately captured by the in-mirror lens 15 via the first mirror 12 and the second mirror 14.

Even when the copying magnification is further changed, the same operation as described above is repeated, making it possible to always accurately move the in-mirror lens to the magnification changing position corresponding to the set magnification.

〔Effect of the invention〕

In this way, the present invention arranges the imaging lens so that its optical axis is oblique to the beam of light reflected from the document surface, and adjusts the direction of the lens optical axis and the reflected light from the document when changing magnification. In a variable magnification device for a copying machine, which is provided so as to be movable in the capturing direction, the imaging lens is movable in the plane direction using a hinge pin as a fulcrum on the front surface of a lens base plate that is integrated with a slide frame body that can move in the direction of its optical axis. The free end side of the movable plate is movably supported by an arcuate long hole and a fixing pin that is loosely inserted into the long hole and protrudes from the surface of the lens base plate. During zooming, the imaging lens can stably move in the direction of the lens optical axis together with the lens base plate integrated with the slide frame. Further, the imaging lens is attached to the front surface of the lens base plate to a movable plate that can be moved in the plane direction using a hinge pin as a fulcrum, and the free end side of the movable plate has an arc-shaped elongated hole and the above-mentioned movable plate is loosely inserted into the long hole. Since it is movably supported by a fixed pin protruding from the surface of the lens base plate, it can be moved accurately in the direction of capturing the reflected light of the document without wobbling.
Moreover, the lens can be stably held at the movement completion position, making it easier to achieve accuracy.

Moreover, since the structure is simple, it can be manufactured at low cost, and has various excellent effects.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the movement of the imaging lens from the same magnification position to the variable magnification position, Fig. 2 is a perspective view of an optical system unit showing an embodiment of the present invention, and Fig. 3 is a partially cutaway side cross section. 4 are perspective views of essential parts. 1... Unit frame, 4, 5... Shaft, 6...
... shaped sliding frame, 7... shaped sliding frame, 8...
... Lens base plate, 9 ... Mirror frame, 15 ... In-mirror lens, 16 ... Pin, 17 ... Movable plate, 2
4...Koro, 25...Curved cam.

Claims (1)

[Claims] 1. An imaging lens is arranged so that its optical axis is oblique to the beam of light reflected from the document surface, and the imaging lens is movable in the direction of the lens optical axis and in the direction of capturing the reflected light of the document when changing magnification. In the variable magnification device of a copying machine, the imaging lens is attached to a movable plate movable in the plane direction using a hinge pin as a fulcrum on the front surface of a lens base plate integral with a slide frame body movable in the optical axis direction, A variable magnification device for a copying machine, wherein the free end side of the movable plate is movably supported by an arcuate long hole and a fixing pin loosely inserted into the long hole and protruding from the lens base plate surface.