JPH079532B2 - Copier optical device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a copying machine to which a variable magnification function is added, in order to perform variable magnification projection on a recording medium for an original image using a fixed focus lens for varying magnification. Optical device.

<Prior Art> In an electrophotographic copying apparatus, when an image of an original is formed on a recording medium (for example, a photoconductor whose surface is composed of a light-conductive layer), an optical device including a large number of mirrors and lenses is used. In the case of forming an equal-magnification image on a recording medium, this optical device has a mirror and an optical path length a between the document surface and the lens so that the optical path length b between the lens and the recording medium surface is a = b. The lens is properly arranged. In this case, a and b are set to be 2f, where f is the focal length of the fixed focus lens. That is, for the focal length f of the lens, a
And b In the case of the same magnification, since a = b, a and b should be set to 2f.

Here, the magnification m projected on the recording medium is In the case of enlarging and projecting onto the recording medium, the lens may be moved closer to the original surface side (left side in FIG. 3), and in the case of reducing and projecting the lens onto the recording medium side. Just go near. Therefore, when performing variable-magnification copying, it is necessary to move the lens. Further, in order to compensate the optical path length (a + b) corresponding to each magnification at the same time as the movement of this lens, it is necessary to move the mirror arranged in the optical path. Conventionally, the movement of the lens and the mirror is moved in association with each other according to the magnification.

<Problems to be Solved by the Invention> Conventionally, if a fixed focus lens is used, the configuration for moving the lens and the mirror in accordance with the projection magnification requires a very complicated and large space. For example, there is a method in which the lens and the mirror are moved by using different drive systems.
In this case, the cost increases, but since the drive systems of both are driven in association with each other, it is necessary to improve both of them with high precision, which further increases the cost.

Further, Japanese Patent Application Laid-Open No. 59-69749 “Optical device for electrophotographic copying machine” discloses a system in which a lens and a mirror are moved according to a magnification by one driving system. In this method, a lens is moved by using a wire driven by a motor in accordance with a magnification change ratio, and a mirror is moved by a plane cam connected to a motor through a connecting means by a required distance. In this example, if the variable power range is wide (stepless variable power or a large number of variable powers), the flat cam or the like tends to be complicated and large.

In addition, in Japanese Utility Model Publication No. 59-39690 (US Pat. No. 4,397,544), a cylindrical cam is provided when the main lens having a fixed focus is moved to a target magnification position according to the copy magnification. It is disclosed that the main lens is moved to a desired position by rotating the cylindrical cam. In connection with the movement of the main lens, an auxiliary lens is rotatably provided so as to overlap the main lens, and a cam plate separate from the cylindrical cam for selectively rotating the auxiliary lens is provided. ing. Therefore, the auxiliary lens is rotated along the cam plate in accordance with the movement of the main lens, and the auxiliary lens is selectively superposed on the optical axis of the main lens. In this case, the number of auxiliary lenses corresponding to each magnification is prepared in advance, each auxiliary lens is rotatably provided, and a plurality of cam plates corresponding to each auxiliary lens are separately provided.

From the above, since it is necessary to provide a cam plate or the like along with the lens movement along the lens movement path along with the movement of the lens, the arrangement space becomes large, and as the zooming factor increases, the cam plate becomes larger. Not only the size of the plate becomes large, but also a configuration such as preparing the number of cam plates corresponding to the number is required, and the entire optical device becomes very large in order to secure the arrangement space. Therefore, it has been a general idea to use the variable magnification to a certain extent when variable magnification copying is performed using a fixed focus lens. Therefore, when setting multi-step copy magnification,
It was impossible to use a very inexpensive fixed focus lens, and there was no choice but to use a very expensive zoom lens.

Therefore, it is an object of the present invention to provide an optical device using a fixed focus lens which has a simple structure and is suitable for stepless zooming. Particularly, the present invention is an optical device capable of moving a lens and a mirror by one driving system.

<Means for Solving Problems> In order to solve the above-mentioned problems, the present invention connects a cylindrical cam rotated by a driving force of a motor or the like and a mirror holding member that holds a mirror and is movable. The lens holding member holding the lens is further moved by a driving force for rotating the cylindrical cam via a moving means such as a wire.

<Operation> According to the optical device configured as described above, since the rotational force of the drive source such as the motor directly drives the moving means such as the cylindrical cam and the wire, the connecting means for moving the mirror. Is simplified, and the mirror can be moved steplessly and accurately according to the rotation of the cylindrical cam.

<Embodiment> FIG. 1 is a plan view showing a lens and mirror moving mechanism of an optical device according to the present invention, FIG. 2 is a perspective view showing details of a mirror moving mechanism according to the present invention, and FIG. It is a side view which shows the whole structure of an apparatus.

First, in FIG. 3, reference numeral 1 is a document, 2 is a cylindrical recording medium on which a document image is projected, and 3 is an optical device arranged between the document and the recording medium for projecting an optical image. The optical device 3 according to the present invention is, for example, a first reflection mirror 30, which receives and reflects a reflected light image from an original,
Second and third reflection mirrors 31, 32 for inverting the optical path of the reflected light image from the first reflection mirror 30, a projection lens 33 having a fixed focal length f, and a reflected light image passing through the lens 33. It comprises a fourth and fifth reflecting mirrors 34 and 35 for reversing the optical path and a fixed reflecting mirror 36 for directing the reflected light image from the fifth reflecting mirror 35 onto the surface of the recording medium 2. In order to optically scan the entire length of the manuscript 1, the optical device 3 moves the manuscript 1 itself, and in addition to the first manuscript, the first reflecting mirror 30 and the second and third reflecting mirrors 31 with respect to the fixed manuscript. , 32
Are moved parallel to the original 1 at the speeds of v and v / 2. However, v changes according to the copy magnification m, and the scanning speed vm of the reflecting mirrors 31 and 32 at the time of zooming is vm = v / m.

Further, in the optical device 3, the lens 33 and the fourth and fifth reflecting mirrors 34, 35 are moved in the arrow direction according to the projection magnification. The lens 33 is fixed and held on the lens holding member 4 as shown in FIG. The fourth and fifth reflection mirrors 34 and 35 are attached to the same mirror holding member 5. The lens holding member 5 is a guide rail 6 for moving the lens.
The mirror holding member 5 is slidable with respect to the rail 8 via a slide member 7 for holding the mirror.
It is provided so that it can slide along. The slide member 7 is fixed to the mirror holding member 5 and slides along the slide rail 8.

Next, a configuration for moving the lens and the mirror holding members 4 and 5 according to the magnification will be described below. A wire 9 is fixed to the lens holding member 4, and the wire 9 is stretched around three pulleys 10, 10 and 11. Pulley 10
Is rotatably provided, and the pulley 11 is a drive gear 12
Are coaxially fixed and drive the wire 9. Further, the gear 12 meshes with a gear 13 directly connected to a rotating shaft of a motor (not shown), and the rotational force of the motor is transmitted to drive the wire 9. The above is the configuration of the mechanism for moving the lens 33. The guide rail 6 is inclined, but this is for projecting onto the recording medium 2 with one side of the original 1 as a reference.

Then, the mirror 3 that is moved in conjunction with the movement of the lens 30
The moving mechanisms 4 and 35 include a rack 15 that meshes with a pinion gear 14 that is directly connected to a gear 13 of the rotating shaft of the motor. The rack 15 is rotatably provided around a shaft 16, and the shaft 16 is provided with a cylindrical cam 17 that rotates simultaneously with the rack 15. The rack 15 is fixed to or integrally formed with the cylindrical cam 17, and can directly transmit the rotation of the motor or the like to the cylindrical cam 17 without the need for transmitting the rotation to the cylindrical cam 17. In this case, in the conventional case, the rotational force of the motor is generally transmitted to a rotating shaft such as a cam via another transmitting means, and the influence of backlash of the shaft of the cam and the transmitting means is affected. The rotation of the motor etc. was not transmitted accurately. However, since the cylindrical cam 17 is integrally formed or fixed to the rack 15 to which the rotational force of the motor is directly transmitted as in the present invention, the cylindrical cam 17 can be accurately rotated according to the rotation of the motor.

A shaft 16 which is rotatably provided with a member integrally forming the rack 15 and the cylindrical cam 17 is attached to a cylindrical cam holder 18. E-rings 19 are fixed to both ends of the shaft 16,
The holder 18 is prevented from falling off. The E-ring 19 _-1 provided on the shaft 16 is used for positioning the cylindrical cam 17, and the rack 15 is further moved by the urging force of the spring 20 interposed between the cylindrical cam 17 and the holder 18. Is restricted, and the cylindrical cam 17 is positioned. This cylindrical cam 17
A guide 21 is formed on the circumference of the circle for moving the mirror holding member 5 according to the magnification. Guide 21
It is calculated and set in advance so as to match each magnification. That is, Is well known, and the original 1 and the recording medium 2 at the same size are
And the total optical path length L of L and L are in the relationship of L = a + b = 4f.
Here, a is the optical path length from the surface of the original 1 to the lens 33, b is the optical path length from the lens 33 to the recording medium 2, and f is the fixed focal length of the lens 33, as described above. And in the case of scaling Becomes It should be noted that m is a magnification in variable magnification. As a result, the total length Lm of the optical path during zooming is From equation (1) Becomes Therefore, at the time of zooming, the mirror holding member 5 may be moved in order to secure the entire optical path length Lm as shown in the expression (2). However, according to the embodiment shown in FIG. 1, since the two mirrors of the fourth and fifth reflecting mirrors move at the same time, the movement amount x of the holding member 5 is calculated from the equation (2). Becomes Therefore, the guide 21 of the cylindrical cam 17 is formed so as to obtain the movement amount x of the mirror. That is, x is Becomes

In order to move the mirror holding member 5 with respect to the guide 21 of the cylindrical cam 17 formed as described above, the guide crimping mechanism 22 attached to the slide member 7 on the mirror holding member side that constitutes the mirror moving mechanism is provided. It is provided. The guide crimping mechanism 22 includes a holding member 2 for holding the crimping rollers 24, 25 at the tip of a shaft 23 whose one end is fixed to the slide member 7.
6 is rotatably provided. The pressure roller 24 is rotatably provided on the shaft 27 attached to the holding member 26, and the pressure roller 25 is moved to the holding member 26 in the direction of the pressure roller 24 with a considerable distance from the pressure roller 25. Is rotatably provided at the tip of the attached shaft 28.
The shafts 27, 28 attached to the holding member 26 are biased by the spring 29, and the shaft 28 is biased in the direction of the shaft 27. Therefore, each pressure roller 2 at the tip of the shaft 27, 29
Since 4,25 are arranged so as to sandwich the guide 21 of the cylindrical cam 17, the guides 21 are pressed by both sides of the spring 29 with moderate pressure. Therefore, when the cylindrical cam 17 rotates via the rack 15 in accordance with the rotation of the motor, the mirror holding member 5 is moved along the guide 21 by the crimping mechanism 22.

According to the optical device configured as described above, the motor for moving the lens and the mirror is normally or reversely rotated according to the copy magnification m, and the rotation angle at this time is determined according to the copy magnification. When the motor rotates, the wire 9 is driven and the lens holding member 4 is moved according to the copy magnification m. Therefore, the lens 33 is moved by the distance corresponding to the magnification m. The moving distance y at this time is y = f (1-m) (4). That is, if the magnification m is reduced, the lens 33 is moved to the right by the equation (4) in FIG. On the contrary, in the case of enlargement, the lens 33 is moved leftward. However,
This is the case where the position of the lens 33 shown in FIG. 3 is the same magnification position.

On the other hand, simultaneously with the movement of the lens 33, the fourth and fifth reflection mirrors 34 and 35 are moved to the right according to the magnification m. At this time, since the cylindrical cam 17 is directly transmitted from the motor to the rack 15 to rotate, the configuration becomes very simple. Further, since the cylindrical cam 17 is rotated to move the fourth and fifth reflecting mirrors 34 and 35, not only can a wide zoom range be secured by changing the shape of the guide 21 provided on the peripheral surface of the cylindrical cam 17. ,
The overall shape of the cam does not become complicated and the space does not become wide.

Although the holding member 4 of the lens 33 is moved by the wire 9 according to the embodiment of the present invention, the present invention is not limited to this, and it may be moved by providing a belt, a chain, gears, a pinion, a rack, or the like. Good. Further, the rack 15 directly fixed to the cylindrical cam 17 may be a normal gear,
On the other hand, a pinion 14 attached to the rotary shaft of the motor
Should be replaced with a normal gear.

<Effect> According to the optical device of the present invention, the mirror and the lens can be simultaneously moved by one driving source according to the magnification. In this case, only by forming a guide for deciding the mirror position corresponding to the copying magnification on the peripheral surface of the cylindrical cam, a mechanism for connecting the mirror moving portion to the guide is provided, and the mirror can be moved by a very simple structure, which is small in size. And cost reduction. Moreover, by simply rotating the cylindrical cam, the transmission efficiency from the drive source is increased and the mirror can be accurately moved.

Particularly, by fixing or integrally forming a gear, which is a transmission member directly connected to the drive source, to the cylindrical cam, the rotation and the like from the drive source can be accurately transmitted.

[Brief description of drawings]

1 is a plan view showing a mechanism for moving a lens and a mirror of an optical device according to the present invention, FIG. 2 is a perspective view showing details of a mechanism for moving a mirror shown in FIG. 1, and FIG. 3 is an optical system according to the present invention. It is a side view showing an example of the whole composition of a device. 1: Original, 2: Recording medium, 3: Optical device, 33: Lens, 34, 35:
Fourth and fifth reflection mirrors, 4: mirror holding member, 5: lens holding member, 6: guide rail, 8: slide rail, 9: wire, 14: pinion, 15: rack, 17: cylindrical cam, 21: Guide, 22: Crimping mechanism

Claims (2)

[Claims] 1. An optical device (3) for projecting an image of a document on a recording medium, wherein a focus fixing lens (33) constituting the optical device is moved in accordance with a set copy projection magnification. In order to secure an optical path length according to the magnification, a mirror (34, 35) is movably provided in the optical path direction, and is moved to a position according to the copying projection magnification. A cylindrical cam (17), which is rotated by transmitting the rotational force of a drive source (13) for moving it to a position according to a set copy projection magnification, and the copy projection on the rotating peripheral surface of the cylindrical cam. A guide (21) formed in a shape that moves the mirrors (34, 35) to a position corresponding to the magnification, and a guide (21) connected to the guide and corresponding to the set copy projection magnification from the original to the recording medium. Movable to secure the entire optical path length The mirrors mirror moving mechanism for moving the (34, 35) by the guide (22,7,23)
An optical device for a copying machine, characterized by comprising: 2. A copying machine according to claim 1, characterized in that means (15) for transmitting the rotational force of a drive source for rotating the cylindrical cam is directly fixed to or integrally formed with the cylindrical cam. Optical device.