JPH06202239A - Link mechanism of optical system - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a device by providing a cam member for a link which inputs the driving power from a cam surface via a first cam arm then via a second cam arm to a moving frame for optical path length adjustment when a lens unit is displaced. CONSTITUTION:A link mechanism 373 interlockingly displaces the moving frame 3C for optical path length adjustment along an optical path PS 1 in correspondence to the displacement of the lens unit 37A. This link mechanism 373 has the cam surface 374 and the cam member 375 for the link. The cam member 375 is a L-shaped resin molded article integrally having the first cam arm 375a and the second cam arm 375b. The first cam arm 375a is slidably engaged with the cam surface 374 via a projection a1 provided at its longitudinal front end. The second cam arm 375b is engaged with an input member C1 of the moving frame 3C at its longitudinal front end. Since a large interlocked moving distance can be taken by the lever ratio of the first cam arm 375a and the second cam arm 375b, the dent quantity D of the cam surface 374 is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system link mechanism, and more particularly to an optical system link mechanism for changing the magnification of a document image to form an image.

[0002]

2. Description of the Related Art Generally, an optical system of this type uses a fluorescent lamp for illuminating a document and a first mirror for guiding light reflected from the document to a predetermined optical path as an illumination scanning moving frame for illuminating and scanning the document. And a second moving frame having the second and third mirrors fixed thereto are arranged so as to be able to reciprocate in parallel with the original. Then, the original is illuminated and scanned by moving the moving speed of the first moving frame at a speed of a predetermined ratio with respect to the moving speed of the second moving frame (1/2 speed in the case of equal magnification). (For example, JP-A-1-31
5775 gazette).

On the other hand, the lens of the lens unit is arranged in the optical path from the third mirror of the second moving frame to the fourth mirror fixed to the third moving frame for adjusting the optical path length.
The lens unit is configured to be relatively displaceable with respect to the second moving frame along the above-mentioned optical path, and the optical path length from the lens to the image forming section is different from the optical path length from the document to the lens. Is set to a predetermined ratio (1/2 for equal magnification) so that the original image is formed on the image forming unit at a desired magnification.

In order to relatively displace the lens unit,
A drive wire is fixed to the lens unit, and the drive wire is configured to be driven in a predetermined direction by an optical system motor. On the other hand, the lens unit and the third moving frame are connected via a link mechanism, and the optical path from the lens to the image forming unit is linked by interlocking the third moving frame according to the displacement of the lens unit. I was adjusting the length.

Specifically, the drive wire for driving the lens unit is wound around the outer circumference of the cam pulley, and a part of the drive wire is fixed to the third moving frame. Then, the cam pulley is moved to the third position corresponding to the displacement of the lens unit.
In order to displace the moving frame, the center of rotation is eccentric with respect to the center of the outer peripheral surface around which the drive wire is wound.

[0006]

In order to popularize the image forming apparatus employing the optical system having the above-mentioned configuration for home and personal use, it is preferable to make the size and weight as small as possible. However, in the above-described conventional optical system link mechanism, since the cam pulley whose center of rotation is eccentric with respect to the center of the outer peripheral surface around which the drive wire is wound is adopted, the interlocking distance of the third moving frame is reduced. In order to set a large value, it is necessary to set the outer diameter of the cam pulley and the eccentricity amount to a considerably large value. As a result, the lens unit itself becomes large, which makes it impossible to reduce the size and weight of the apparatus. In particular, in order to set a large range of changeable magnification, it is necessary to set a large range in which the third moving frame is interlocked with each other, resulting in further increase in size. This greatly limits the range of the enlargement value and the reduction value of the document image in the conventional image forming apparatus developed for home use and personal use.

The present invention has been made in order to solve the above-mentioned problems, and aims to reduce the size of the lens unit itself,
Not only can the size and weight of the entire apparatus be reduced, but the range of the enlargement value and reduction value of the original image of the image forming apparatus developed for home and personal use can be set widely. The purpose is to provide a link mechanism.

[0008]

In order to solve the above-mentioned problems, the link mechanism of the optical system of the present invention provides a moving frame for adjusting the optical path length in correspondence with the displacement of the lens unit when the magnification of the original image is changed. In a link mechanism of an optical system to be interlocked, a cam surface formed integrally with a lens unit and smoothly recessed in a direction substantially orthogonal to a displacement direction of the lens unit, and a longitudinal end portion thereof are engaged with the cam surface. The first cam arm to be joined and the first cam arm from the longitudinal base end portion of the first cam arm to the first cam arm.
Second cam arm extending in a direction substantially orthogonal to the cam arm and having its longitudinal end engaged with the moving frame, and is provided at a substantially intersecting portion of both cam arms to pivotally support both cam arms. A link cam member that includes a fulcrum member and that inputs a driving force from the cam surface to the moving frame from the first cam arm through the second cam arm when the lens unit is displaced. There is.

[0009]

According to the link mechanism of the optical system of the present invention having the above-mentioned structure, when the lens unit is displaced along the optical path when the magnification of the original image is changed, the cam surface is also displaced integrally with the optical path. Thereby, the first cam arm is rotated around the fulcrum member. As a result, the second cam arm also has the first
Since the driving force is input to the moving frame by rotating integrally with the cam arm, the link cam member can displace the moving frame along the optical path in response to the movement of the lens unit.

Here, in the link mechanism of the optical system of the present invention, the second cam arm is extended from the longitudinal base end portion of the first cam arm in a direction substantially orthogonal to the first cam arm. In addition, since a fulcrum member is provided at the substantially intersection of both cam arms, depending on the lever ratio of the first cam arm and the second cam arm,
As a result of the large interlocking distance in the optical path direction, the amount of depression of the cam surface can be set small.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic bottom view showing an essential part of this embodiment at the same magnification, and FIG. 2 is a schematic bottom view showing an essential part of this embodiment at an enlargement.
FIG. 1 is a schematic diagram showing an internal configuration of a copying machine as an image forming apparatus adopting this embodiment.

First, referring to FIG. 3, in the copying machine of this embodiment, the original placed on the original placing plate 2 is illuminated and scanned inside the main body 1 of the copying machine, and the reflected light from the original is reflected. And an optical system 3 for guiding the photosensitive drum 42 to the photosensitive drum 42, and an electrostatic latent image formed on the photosensitive drum 42 is visualized by the developing device 41 and then transferred to a sheet. Image part 4
A fixing unit 54 for fixing the toner image transferred to the paper is arranged in the middle, and the paper is pulled out from the paper feed tray 61 of the paper storage unit 6 by a paper feed roller 51 having a half-moon shape. A sheet conveying unit 5 for ejecting to a discharge tray 56 in the copying machine main body 1 through the image forming unit 4 is provided.

The optical system 3 illuminates an original with a fluorescent lamp 39 having a reflecting plate 38 fixed to the first moving frame 3A, and reflects light from the original on the first moving frame 3A. 1 mirror 31, the second fixed to the second moving frame 3B
Mirror 32 and third mirror 33, lens 37, fourth mirror 34 and fifth mirror 3 fixed to third moving frame 3C
5 and the sixth mirror 36 fixed to the main body 1 of the copying machine in order to lead to the photosensitive drum 42.

The lens 37 is arranged in the optical path PS1 from the third mirror 33 to the fourth mirror 34, and is configured to be displaceable along the optical path PS1 via the lens unit 37A. To describe in more detail with reference to FIGS. 1 and 2, the lens unit 37A includes a third lens unit 37A.
A rack gear 371 made of resin is provided that extends along the optical path PS1 from the mirror 33 to the fourth mirror 34. The rack gear 371 is slidably supported by an optical bar 1b fixed to the optical frame 1a of the copying machine main body 1. The pinion gear 372 meshing with the rack gear 371 is rotationally driven in a predetermined direction when the magnification of the original image is changed, so that the lens unit 37A is moved relative to the second moving frame 3B. On the other hand,
The lens unit 37A and the third moving frame 3C are connected via a link mechanism 373, and the lens unit 37A
The optical path length from the lens 37 to the image forming unit 4 (see FIG. 3) can be adjusted by interlocking the third moving frame 3C corresponding to the displacement of A. In other words, the link mechanism 373 configures the third moving frame 3C as a moving frame for adjusting the optical path length.

The link mechanism 373 is integrally formed on the back surface of the rack gear 371 of the lens unit 37A and is substantially orthogonal to the displacement direction of the lens unit 37A (left and right direction in FIGS. 1 and 2). By engaging the cam surface 374 that is smoothly recessed in the front and the cam surface 374, it is possible to correspond to the movement of the lens unit 37 </ b> A to the third surface.
A link cam member 375 for displacing the moving frame 3C along the optical path PS1 is provided.

The link cam member 375 is a resin-molded product having a first cam arm 375a and a second cam arm 375b which are integrally provided and which are substantially L-shaped in a plan view. First cam arm 375a
Is always slidably engaged with the cam surface 374 through a projection a1 provided at the tip in the longitudinal direction. Then, from the longitudinal base end portion of the first cam arm 375a,
The second cam arm 375b is extended. The second cam arm 375b extends in a direction substantially orthogonal to the first cam arm 375a, and its longitudinal end portion is engaged with the input member C1 of the third moving frame 3C. This input member C
Reference numeral 1 denotes a projecting member that hangs integrally from the lower surface of the third moving frame 3C. One end of the surface opposite to the surface with which the second cam arm 375b is engaged is one end of the copying machine main body 1 Is urged by a compression coil spring SP fixed to a standing piece 11a standing on the optical frame 1a.

The link cam member 375 is formed integrally with the fulcrum member 375c. Fulcrum member 375
c is provided substantially at the intersection of the cam arms 375a and 375b, and is rotatably supported by the bottom plate of the optical frame 1a to pivotally support the cam arms 375a and 375b. According to the link mechanism 373 of the optical system of the present embodiment having the above configuration, when the magnification of the original image is changed, the lens unit 37A is displaced along the optical path PS1 from the position shown in FIG. 1 to the image enlargement position shown in FIG. Then,
The cam surface 374 is also displaced leftward in the figure integrally with the cam surface 374. As a result, the cam surface 374 causes the first cam arm 375a to pivot clockwise around the fulcrum member 375c in FIGS. As a result, the second cam arm 375b also resists the urging force of the compression coil spring SP, and thus the first cam arm 3 can be prevented.
Since the driving force is input to the third moving frame 3C by rotating integrally with 75a, the link cam member 375 moves the third moving frame 3C along the optical path PS1 in response to the movement of the lens unit 37A. Can be displaced to the right side of the figure.

Here, the link mechanism 3 of the optical system of the present embodiment.
In the reference numeral 73, the second cam arm 375b extends from the base end portion in the longitudinal direction of the first cam arm 375a in a direction substantially orthogonal to the first cam arm 375a, and both cam arms 375a, 375b. Since the fulcrum member 375c is provided substantially at the intersection, the first cam arm 375a and the second cam arm 37
With the lever ratio of 5b (about 1: 1 in this embodiment), a large interlocking distance can be obtained in the optical path PS1 direction, and as a result, the depression amount D (35 mm in this embodiment) of the cam surface 374 is set small. be able to.

As described above, according to the link mechanism 373 of the optical system of this embodiment, the lever ratio of the first cam arm 375a and the second cam arm 375b allows a large interlocking distance in the optical path PS1 direction. Since the cam surface 374 having a relatively small recess amount D can be adopted, not only the lens unit 37A itself can be downsized and the overall size and weight of the device can be reduced, but also for home and personal use. The remarkable effect is that the range of the enlargement value and the reduction value of the original image of the image forming apparatus developed as can be set wide.

The above-described embodiment is merely an example of the preferred embodiment of the present invention. For example, the fulcrum member 375.
It goes without saying that various design changes can be made within the scope of the claims, such as c being formed of a member (preferably a metal member) different from the first and second cam arms 375a and 375b.

[0021]

As described above, according to the link mechanism of the optical system of the present invention, the lever ratio of the first cam arm and the second cam arm provides a large interlocking distance in the optical path direction, Since a cam surface having a relatively small amount of depression can be adopted, not only can the lens unit itself be downsized and the overall size and weight of the device can be reduced, but it can also be developed for home and personal use. The remarkable effect is that the range of the enlargement value and the reduction value of the original image of the image forming apparatus can be set wide.

[Brief description of drawings]

FIG. 1 is a schematic bottom view showing a main part of the present embodiment at the same magnification.

FIG. 2 is a schematic bottom view showing the main part of the present embodiment at the time of enlargement.

FIG. 3 is a schematic diagram showing an internal configuration of a copying machine as an image forming apparatus adopting this embodiment.

[Explanation of symbols]

 1 Copier main body (image forming apparatus) 3 Optical system 3C Third moving frame 37 Lens 37A Lens unit 373 Link mechanism 374 Cam surface 375 Link cam 375a First cam arm 375b Second cam arm 375c Support point member

Claims (1)

[Claims] 1. A link mechanism of an optical system for interlocking a moving frame for adjusting an optical path length corresponding to a displacement of a lens unit at the time of changing the magnification of an original image, the mechanism being integrally formed with the lens unit, A cam surface that is smoothly recessed in a direction substantially orthogonal to the displacement direction, and a first cam arm whose longitudinal tip engages with the cam surface.
A second cam arm extending from the base end portion in the longitudinal direction of the first cam arm in a direction substantially orthogonal to the first cam arm, the distal end portion in the longitudinal direction engaging with the moving frame; and both cams. It includes a fulcrum member that is provided substantially at the intersection of the arms and pivotally supports both cam arms, and when the lens unit is displaced, the driving force from the cam surface is moved from the first cam arm through the second cam arm. A link mechanism for an optical system, comprising: a link cam member for inputting to a frame.