JPS61246733A - Lens moving mechanism for copying machine - Google Patents

Abstract

PURPOSE:To move a lens frame accurately on a position corresponding to the variable power of copying and to improve the response of start at the time of movement by moving the lens frame to a fixed position by a click mechanism. CONSTITUTION:A guide block 30 is united with the lens frame 28 in which an image formation lens 10 is included, and when the block 30 is moved while being guided by a guide plate 33 fixed on a base plate, the lens 10 is moved forward and backward in the direction of an optical axis 16. The block 30 is provided with a supporting plate 34 united with the lens frame 28, a click lever 37 to be vibrated around a shaft 36 in a recessed part formed on the supporting plate 34 and a spring 38 for providing energizing force to the lever 37. A plate 33 is inserted into the recessed part. When the block 30 is moved in accordance with the plate 33, a roller 42 is pressed against the edge of the plate 33, rotated and engaged with any one of click grooves 40a-40c, so that the lens frame 28, i.e. the image formation lens 10, can be positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens moving mechanism for a copying machine for accurately moving an imaging lens to a predetermined position according to a copying magnification.

[Conventional technology]

In a copier that can change the copying magnification, at least a part of the imaging lens installed between the document and the recording surface of a photosensitive drum, etc. is attached to a lens frame that is movable in the direction of the optical axis. The lens frame is moved to a position corresponding to the copying magnification. For example, inexpensive copying machines use a fixed-focus imaging lens, and the lens frame that holds the entire imaging lens is moved to a position corresponding to the copying magnification. .

By the way, as a conventional method for moving the lens frame in the optical axis direction as described above, a female thread is formed in the lens frame, and the above-mentioned screw is attached to the feed screw extending in the optical axis direction of the imaging lens. There is one in which the female threaded portion is screwed together and the lens frame is moved forward and backward by rotating this feed screw with a servo motor or the like. In addition, there are also known devices in which a motor is used as a drive source, and an interlocking mechanism using a rack or pinion, or an interlocking mechanism using a belt and a helicoid is provided between the lens frame and the lens frame to move the lens frame forward and backward in the optical axis direction. There is.

[Problem that the invention seeks to solve]

However, when moving the lens frame as described above, the lens frame is always connected to the motor via an interlocking mechanism such as a feed screw, so even if you try to control the stop of the motor with high precision, However, it is difficult to accurately stop the lens frame at a target stop position due to the influence of the inertia of the motor, the interlocking mechanism connected thereto, the lens frame, etc.

Furthermore, since the lens frame and the motor for moving the lens frame are always in a connected state, there is a drawback that the load upon starting the motor is large and the response upon starting is poor.

1 The present invention has been made in order to eliminate the drawbacks of the above-mentioned prior art, and it is a method of accurately moving a lens frame holding a lens that is moved for magnification to a fixed position according to the copying magnification. It is an object of the present invention to provide a lens moving mechanism that can move a lens frame and has improved responsiveness at startup when moving a lens frame.

[Means for solving problems]

In order to achieve the above object, the present invention moves a lens frame holding a variable power lens to a predetermined position using a feeding mechanism, and then further feeds the lens frame in the same direction using a click mechanism. , the lens frame is positioned at a fixed position set according to the copying magnification. When the lens frame is moved to a certain position by the click mechanism, the connection between the lens frame and the feeding mechanism is severed. Note that the lens held in the lens frame may be the entire imaging lens or a part thereof, as long as it is a lens that is moved for zooming. be.

According to a preferred embodiment of the present invention, the lens frame is formed with a guide part, and the movement of the lens frame in the optical axis direction is correctly guided by interaction with the guide plate that engages with the guide part. It has become. By providing the click mechanism between the guide portion and the guide plate, the click mechanism not only positions the lens frame but also guides the lens frame.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the attached drawings.

〔Example〕

In FIG. 6 showing the optical system of a copying machine using the present invention,
Place the original 2 with the original surface facing down on the original placing surface 1 made of a glass plate or the like, and when the original placing surface 1 is moved in the direction of arrow 3, the image of the original illuminated by the light source 4 will be reflected in the slit. 5, it is scanned as a line-shaped image. Then, this line-shaped image is transmitted to the photosensitive drum 1 via the mirror 6.7.8, the imaging lens 10, the mirrors 11, 12.13.
The image is formed on 4. Since the photosensitive drum 14 rotates around the shaft 15 while maintaining a constant relationship with the movement of the document placement surface 1, an image of the entire surface of the document 2 can be recorded on the photosensitive drum 14.

The imaging lens 10 is composed of a lens with a fixed focus, but by changing the optical path length from the original 2 to the photosensitive drum 14 and moving the imaging lens 10 along the optical axis 16, it is possible to perform copying. In addition to the same magnification, 1.224
It is possible to change it to 0.817 times or 0.817 times. First, in order to obtain the same copying magnification, when the focal length of the imaging lens 10 is f, the total optical path length Lo from the original 2 to the photosensitive drum 14 is 4f, and then from the original 2 to the image forming The imaging lens 10 may be moved to a position such that the object-side optical path length La from the imaging lens 10 to the photosensitive drum 14 and the image-side optical path length Lb from the imaging lens 10 to the photosensitive drum 14 are each 2f.

In addition, when increasing the magnification to 1.224 times, move the imaging lens 10 to a position where the object side optical path length La is (1+0.817)f and the image side optical path length Lb is (1+1.224)f. let In this case, the mirror holder 17 holding the mirrors 11 and 12 is moved in the direction of the arrow 18, and the total optical path length Lo becomes 4.041f, which is longer than when the image is at the same magnification.

Furthermore, the magnification is 0, 81, which is the reciprocal of the above 1.224 times.
When obtaining a 7x reduction magnification, the total optical path length Lo is 4.041f, which is the same as when obtaining a 1.224x magnification.
, and move the imaging lens 10 in the direction of the arrow 20, that is, closer to the photosensitive drum 14 side. At this time, the object side optical path length La becomes (1+1.224)f, and the image side optical path length Lb becomes (1+0.817)f.

In this way, if the reciprocal of the enlarged copy magnification of N times is set to 1/N times as the reduced copy magnification, two types of magnification can be obtained while keeping the total optical path length the same, which is very effective. It's convenient.

FIG. 1 shows an imaging lens 10 and the mirror holder 17.
It shows the mechanism for moving the. A guide block 30 is integrated into the lens frame 28 in which the imaging lens 10 is incorporated, and this guide block 30 is connected to the substrate 3.
The imaging lens 10 moves forward and backward in the direction of the optical axis 16 by being guided by a guide plate 33 fixed to the optical axis 2 . Note that the guide plate 33 is arranged obliquely with respect to the optical axis 16, and as the imaging lens 10 is advanced or retreated along the optical axis 16 when changing the copying magnification, the optical axis of the imaging lens 10 is 16 is moved in parallel so that it is directed to the center of the screen corresponding to the copying magnification.

As is clear from FIG. 2 showing the structure on the bottom side and FIG. 3 showing the cross section, the guide block 30 includes a support plate 34 that is integrated with the lens frame 28, and a recess formed in the support plate 34. The click lever 37 is provided with a click lever 37 that swings around a shaft 36 within the click lever 35, and a spring 38 that applies a biasing force to the click lever 37. Further, a guide plate 33 is inserted into the recess 35 .

The guide plate 33 has V-shaped click grooves 40a and 40b for positioning the lens frame 28, that is, the imaging lens 10, at a position corresponding to the copying magnification.
, 40 c are formed. When the guide block 30 is moved along the guide plate 33, the click lever 3 is biased by the spring 38.
The roller 42 provided at 7 is pressed by the edge of the guide plate 33 and rolls, and engages with any of the click grooves 40a to 40c to close the lens frame 28, that is, the imaging lens 10.
positioning.

Note that reference numerals 39a and 39b are guide cam surfaces 33a formed on the guide plate 33, respectively.

The guide piece that comes into contact with the guide plate 33b is shown.
It is used to eliminate backlash when the guide block 30 moves along the guide block and to obtain accurate guiding action. Also,
The raised portion 35a formed in the recessed portion 35 prevents the guide block 30 from wobbling in the surface direction of the guide plate 33.

In order to move the guide block 30, a fork portion 43 consisting of protrusions 43a and 43b is formed on the side surface of the guide block 30, and a groove 46 through which the wire 45 passes is provided in the protrusions 43a and 43b. The wire 45 has
The outer shape is 1 to fit between the protrusions 43a and 43b.
An actuating piece 47 larger than the width of l146 is fixed.

The wire 45 forms a loop and is hung on a pulley 50 via an intermediate roller. Large diameter portion 51 of pulley 50
A drive wheel 53 driven by a motor 52 fixed to the lower surface of the base plate 32 is in pressure contact with the base plate 32 . By driving the motor 52, the wire 459 actuating piece 47. The guide block 30 moves via the fork portion 43. motor 5
The second stop control is performed using a light shielding piece 55 fixed to the lens frame 28.
This is done by photosensors 57a to 57c that detect.

An opening 60 is formed in the substrate 32. This opening 60
Inside is a mirror 11.1 that deflects the optical axis 16 by 180@.
2 (see FIG. 6) is installed. Rollers 61 that are pivotally attached to both sides of the mirror holder 17 ride on the edges of the opening 60, so that the mirror holder 17 can move forward and backward within the opening 60 along the direction of the optical axis 16.

A mirror drive stand 63 is positioned and screwed onto the substrate 32. Since the spring 64 is applied between the mirror drive stand 63 and the mirror holder 17, the mirror holder 17 is always biased to the right.

A cam 66 is rotatably attached to a pair of shafts 65 implanted in the mirror driving table 63, respectively. These cams 66 include, as shown in FIG.
Two circumferential surfaces 67.6 with different radii centered on the axis 65
8 is formed. Also, a pin 7 is provided on the top surface of the cam 66.
0 is formed, and this pin 70 is connected to the link lever 71.
It is inserted into a hole formed in the.

At one end 71a of the link lever 71, there is an oval opening lower part 2.
is formed. During this time, a disk 73 fixed to the upper surface of the large diameter portion 51 of the pulley 50 is fitted into the lower 2 .

Since the disk 73 is formed at an eccentric position with respect to the shaft 74 which is the rotation center of the pulley 50, when the pulley 50 is rotated, it moves to the position shown by the solid line in FIG.
That is, a position where the link lever 71 is slid to the left and a position shown by a chain double-dashed line where the link lever 71 is slid to the right are taken.

If the disc 73 is screwed onto the upper surface of the pulley 50 after adjusting the position N, when the disc 73 reaches the solid line position in FIG. 4, the cam 66 is rotated via the pin 70.
The small radius circumferential surface 68 is brought into contact with the back surface 17a of the mirror holder 17, and when the disk 73 comes to the position shown by the two-dot chain line, the large radius circumferential surface 67 of the cam 66 comes into contact with the rear surface 17a of the mirror holder 17. It can be made to abut against the back surface L7a. As mentioned above, since the mirror holder 17 is urged backward by the spring 64, by determining the rotational position of the cam 66, the mirror 11 can be moved along the optical axis 16.
It becomes possible to perform 12 positionings. Also, cam 6
Each of the circumferential surfaces 67 and 68 of the cam 66 is formed within a certain angular range, so in order to control the amount of rotation of the cam 66, it is sufficient to keep the circumferential surfaces 67 and 68 within that angular range at each position. .

The effects of the above configuration will be explained below.

In the state shown in FIG. 1, that is, when the click lever 37 in the guide block 30 is engaged with the click groove 40b of the guide plate 33 and positioned, the imaging lens 10 of focal length f is moved from the original 2 to the photosensitive The lens frame 28 is positioned so as to be located at the center of the total optical path length 4f up to the drum 14. Further, the link lever 71 is in an upwardly slid position, the mirror holder 17 is positioned by the circumferential surface 67 of the cam 66, and the mirrors 11 and 12 are positioned such that the total optical path length is 4f. .

When an operation for changing the copy magnification is performed, a signal from the magnification setting section 80 shown in FIG. 5 is input to the controller 82, and the motor 52 is driven via the motor drive circuit 83.

When increasing the copy magnification to 1,224 times, the motor 52 rotates the pulley 50 counterclockwise.

As a result, the lens frame 28 moves forward along the optical axis 16 via the wire 4s and the piece a 47. When the lens frame 28 advances and the light shielding piece 55 is detected by the photosensor 57a, the controller 82 receives this detection signal and the drive of the motor 52 is stopped. At this time, the roller 42 provided on the click lever 37 moves into the click groove 40a.
Since the motor is set to reach the slope of
Even when the lever 2 is stopped, the biasing force of the spring 38 causes the click lever 37 to fall to the bottom of the click groove 40a.
The guide block 30 moves forward slightly and then stops.

That is, regardless of the feeding by the wire 45, the guide block 30. The lens frame 28 is moved and the actuating piece 4
7 is located at a position away from the end surface of the protrusion 43a.

As a result, the lens frame 28 has a Boo IJ50. wire 45
, furthermore, the object side optical path length La from the predetermined enlarged copying position, that is, the original 2 to the imaging lens 10 in a state separated from the drive system consisting of the actuating piece 47, is (1+0.8
17) Positioned at position f. Therefore, even if the stopping positions of the boolean 1J50 and the wire 45 are slightly shifted due to the inertia of the motor 52 or other influences, the position of the imaging lens 10 can be determined accurately. In order to obtain this effect, as shown for the click groove 40c in FIG. It is necessary to set the distance between the protrusion 43a and the protrusion 43b so that the distance s can be large.

Moreover, regarding the click groove 40b, the click lever 3
Considering that 7 engages from both sides, the protrusion 43
In order to do the same with the margin length s2 between b and the actuating piece 47, it is sufficient to set s, +s', ≧l.

As described above, when the lens frame 28 is moved to the enlarged copy magnification position, the disk 73 fixed to the top surface of the IJ 50
is sent to the position shown by the solid line in FIG. and,
Since the link lever 71 is at the position where it is most drawn toward the pulley 50, there is a
A small radius circumferential surface 68 of the cam 66 comes into contact. As a result,
The mirror holder 17 moves backward on the optical axis 16, and the mirror 11.
12 is positioned at a position away from the imaging lens 10. As a result, the total optical path length Lo from the document 2 to the photosensitive drum 14 shown in FIG. 6 is set to 4.041f, which is the length for obtaining an enlargement factor of 1.224 times.

On the other hand, when reducing the copy magnification from the same copy magnification to 0.817 times, the controller 82. The motor 52 is driven via the motor drive circuit 83, but contrary to the above case, the motor 52 is
J50 is rotated clockwise. And the lens frame 28
When the light shielding piece 55 fixed to is detected by the photosensor 57c, the motor 52 is stopped. but,
At this point, the roller 42 of the click lever 37 has reached the slope of the click groove 40c, so even after the feeding of the wire 45 has stopped, as in the case of magnification,
Guide block 30. The lens frame 28 is sent to a predetermined position. When the click lever 37 falls into the bottom of the click groove 4°C of the guide plate 33, the movement of the lens frame 28 is stopped, and the lens frame 28 is moved toward the optical axis 1.
The imaging lens 10 is positioned at a predetermined reduction magnification position that is set back from 6, that is, at a position where the object side optical path length La becomes (1+1.224)f.

In this case as well, the disc 73 is rotated together with the pulley 50, but its stopping position is the position shown by the solid line in FIG. 4, that is, the total optical path length LO is 4 The position will be .041f. therefore,
The position of the mirror holder 17, that is, the mirror 11.12 is 1.
．． While setting the same position as when 224 times, 0.817
It becomes possible to obtain a double copy magnification.

Note that, for example, as shown in FIG. 2, when the lens frame 28 is positioned at the same magnification position, there is an allowance length SI, s! on both sides of the actuating piece 47. Therefore, when the motor 52 is started, only the wire 45 is fed by the allowance length S or s2, so the load at the moment the motor 52 is started is considerably reduced and responsiveness is improved.

〔Effect of the invention〕

As explained above, according to the lens moving mechanism of a copying machine using the present invention, the lens frame that has been sent to a predetermined position by the feeding mechanism driven by the motor is further moved in the same direction by the click mechanism, It is separated from the feeding mechanism and positioned at a fixed position depending on the copying magnification. Therefore, it is not affected by the inertia of the motor or the feeding mechanism connected to it.
It becomes possible to accurately position the lens frame at a fixed position according to the copying magnification. Furthermore, when the lens frame is positioned at a certain copying magnification position, the action of the click mechanism allows some time for the driving force from the feed mechanism to be transmitted to the lens frame, so that the motor cannot be started. It also reduces the time load and improves operational responsiveness.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention. FIG. 2 is a bottom view of the guide block used in the apparatus shown in FIG. 1. FIG. 3 is a sectional view taken along line AA in FIG. 2. FIG. 4 is a plan view of the mirror holder moving mechanism used in the apparatus shown in FIG. 1. FIG. 5 is a block diagram of a circuit configuration used in the apparatus shown in FIG. 1. FIG. 6 is a schematic diagram showing the optical system of a copying machine using the present invention. 10... Imaging lens 14... Photosensitive drum 17... Mirror holder 28... Lens frame 30... Guide block 33... Guide plate 37... Click levers 40a to 40C... Click groove 45... Wire 47... Operating piece 50...Pulley 52...Motor 66...Cam 71...
- Link lever 72... Opening 73... Disc. Procedural amendment September 4, 1985

Claims (3)

[Claims] (1) A feeding mechanism driven by a motor in a copying machine that changes copying magnification by moving a lens frame holding at least a portion of an imaging lens in the optical axis direction, and a feeding mechanism driven by a motor. a transmission means that engages with the lens frame to transmit driving force to the lens frame and moves the lens frame to a predetermined position corresponding to the copying magnification; and a moving direction of the lens frame that has been moved to the predetermined position by the feeding mechanism. and a click mechanism for positioning the lens frame at a predetermined position set by the copying magnification, and by moving the lens frame to the predetermined position by the click mechanism, the communication between the transmission means and the lens frame is provided. A lens moving mechanism for a copying machine, characterized in that the lens is disengaged. (2) The click mechanism engages a click lever swingably provided on the lens frame and a guide portion formed on the lens frame, and serves as a guide when the lens frame is moved in the optical axis direction. Claim 1 comprising a substantially V-shaped click groove formed in the guide plate.
The lens moving mechanism of the copying machine described in . (3) The feeding mechanism is a wire that is loosely inserted into a wire insertion part provided in the lens frame and is sent by a motor, and the transmission means is fixed to the wire and moves the insertion part as the wire is fed. 3. The lens moving mechanism for a copying machine according to claim 2, wherein the mechanism is an actuating piece that moves the lens frame by pressing an end.