JPH0115051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable magnification device for a copying machine that is capable of copying at a plurality of predetermined magnifications, and particularly to a variable magnification device of a type that changes magnification using a zoom lens. The present invention relates to a positioning device.

Conventional magnification changing devices for copying machines include types that use interchangeable single-focal-length lenses with different focal lengths for each magnification, types that change magnification by moving a single single-focal-length lens, and types that use an attachment lens attached to a single-focal-length lens. Variable magnification types are known. However, the first type requires single focus lenses corresponding to the number of set magnification ratios, and also requires a positioning mechanism to position these multiple single focus lenses at predetermined positions, so a large number of magnification ratios can be obtained. It is difficult to do so. In addition, in the second type, the object-image distance changes, so in a copying machine where the document surface and the photosensitive surface are constant, the object-image distance is adjusted between the document surface and the lens or the photosensitive surface of the lens. A mirror and a mechanism for moving it must be provided. Furthermore, with the third type, it is possible to normally change the magnification up to three steps without changing the object-to-image distance, but if you try to change the magnification in more steps than that, you will need another attachment lens. Since attachment/detachment mechanisms must be provided for both attachment lenses, the mechanism becomes particularly complex when increasing the number of variable power stages.

As described above, all three conventional types have complicated structures and are large in size, and cannot meet the recent trends of miniaturization and weight reduction of equipment. In addition, from a productivity standpoint, when manufacturing multiple models with different magnification ratios depending on the specifications of the copier, there are few common parts such as lenses or mechanisms, making it unsuitable for high-variety, low-volume production. be.

A variable magnification device using a zoom lens solves the problems of these conventional devices, and can perform stepless continuous variable magnification without changing the object-to-image distance and without changing lenses or attachments. The biggest feature is that it can be done. Japanese Patent Application No. 55-37841 (Japanese Unexamined Patent Publication No. 56-133756) filed by the present applicant
uses such a zoom lens, and controls its drive and movement position using a numerically controlled motor to enable arbitrary magnification ratios. This device has the advantage that the mechanical structure is simple when considering only the variable magnification device, but the numerical control device is complex and expensive, and when considering the entire copying machine, for example, it rotates by scanning the mirror. In order to enable arbitrary magnification in a copying machine that forms an image of an original on a photoreceptor drum, the mirror scanning speed is continuously changed in accordance with the magnification with respect to the photoreceptor drum, which rotates at a constant speed. Therefore, a high-grade controller such as a numerically controlled motor must be used as a drive motor for mirror scanning. In such a stepless magnification device using a zoom lens, the control system is complicated, sophisticated, and expensive, and therefore it has been difficult to use it in popular models.

However, although it is true that a zoom lens has an important feature of variable magnification in that it is stepless, it is also simple in structure and easy to operate when used only at multiple stages of predetermined magnification. This does not mean that it loses its advantages. When obtaining only such a limited magnification, it is not necessarily necessary to use a high-grade controller such as a numerically controlled motor as a drive source for the zoom lens.

The present invention was made based on such an idea, and includes a magnification changing device for a copying machine that changes the copying magnification by moving the zoom lens between the document surface and the photoreceptor. A stopper plate arranged in conjunction with the stopper plate;
a plurality of contact surfaces corresponding to a plurality of copying magnification positions;
A stopper arm pivotally connected to a zoom lens mount supporting a zoom lens; A stopper roller provided at the free end of this stopper arm; This stopper arm is rotated in a direction in which the stopper roller engages with the abutment surface of the stopper plate. a biasing means for applying force; a lock release plate which is stacked on the stopper plate and is movable in the longitudinal direction of the stopper plate; and a lock release plate formed so as to correspond to an intermediate abutment surface other than both ends of the stopper plate. a holding means that normally holds the lock release plate in a position where the slope release surface does not engage with the stopper roller; and a holding means that normally holds the lock release plate in a position where the slope release surface does not engage with the stopper roller; and the lock release plate is moved on the stopper plate to release the slope lock. The present invention is characterized in that it is provided with a lock release plate drive mechanism that causes the stopper roller to detach from the abutment surface of the stopper plate against the biasing means of the stopper arm.

According to this variable magnification device of a copying machine, the contact surface of the stopper plate allows the zoom lens to be stopped at an accurate copying magnification position, and the lock release plate is driven on the stopper plate to easily and reliably stop the zoom lens. The stoppage can be canceled and the zoom lens can be moved to the next copying magnification position.

The invention will now be described with reference to the illustrated embodiments. Figures 1 and 2 show the principle of an optical system for copying magnification using a zoom lens.
It consists of a lens group 1A and a second lens group 1B. P is the document surface, Q is the photosensitive surface, and FIGS. 1A, B, and C show the positional relationship in the optical axis direction of both lens groups 1A and 1B in the case of enlargement, same-magnification, and reduction, respectively. This figure also shows that when moving the first lens group 1A along straight line A, the second lens group 1A
This shows that B must be moved like curve B.

On the other hand, when positioning a document in a copying machine, it is desirable to be able to place the document in a fixed position regardless of its size or copying magnification. To do this, it is necessary to translate the entire zoom lens 1 in a direction perpendicular to the optical axis by a distance corresponding to the magnification ratio. FIG. 2 shows this relationship. When the magnification ratio changes from enlargement to normal magnification to reduction, the entire zoom lens 1 always has an edge P' of the document surface P and an edge Q' of the photosensitive surface Q. Move on the straight line C connecting the

In order to use the zoom lens 1 to perform copying magnification without changing the object-to-image distance between the document surface P and the photosensitive surface Q and keeping the document set position constant, such a zoom lens 1 is required. It is necessary to combine the movement of the constituent lenses in the optical axis direction and the movement of the entire zoom lens 1 in a direction perpendicular to the optical axis, and the present invention is based on the premise that such a zoom lens 1 is used. There is.

FIGS. 3 and 4 show specific configuration examples in which the zoom lens 1 is caused to move as described above and is stopped at four positions: equal magnification, one step of enlargement, and two steps of reduction. In the third example, assuming that the document surface P is located on the left side of the figure and the photosensitive surface (body) Q is located on the right side, the base 2
A guide rod 3 fixed to is inclined in the direction of straight line C in FIG. 2, and a zoom lens mount 4 is slidably supported on this guide rod 3. The pedestal 4 also rotatably supports a roller 6 that rolls on a guide rail 5 parallel to the guide bar 3, and the pedestal 4 is guided in the direction of the straight line C by both the guide bar 3 and the guide rail 5. be done.

The first lens group 1A of the zoom lens 1 is mounted on the mount 4.
A supporting lens barrel 7 is fixed via a holding member 8. The support barrel 9 of the second lens group 1B is fitted into the first lens group support barrel 7 so as to be slidable in the optical axis direction. Reference numerals 10 and 11 denote guide holes and pins that restrict the rotation of the second lens group supporting barrel 9 and make the sliding direction the optical axis direction. A cam 1 is mounted on the first lens group supporting barrel 7.
2 and a camshaft 14 to which a pulley 13 is fixed are rotatably supported. On the other hand, a roller 16 that comes into contact with the peripheral cam surface of the cam 12 is pivotally supported on a roller mounting member 15 fixed to the second lens group supporting barrel 9 . Reference numeral 17 denotes a tension spring that biases the roller 16 and the cam 12 so that they are always in contact with each other, that is, so that the first lens group 1A and the second lens group 1B approach each other.

A wire 18 whose both ends are fixed to the base 2 is wound around a pulley 13 fixed to a camshaft 14, and fixed at one point in the center. Guide pulleys 19, 19 make the wire 18 coming out of the pulley 13 parallel to the guide rod 3, and are supported on a frame.

As described above, when the mount 4 is moved along the guide rod 3, the entire zoom lens 1 supported by the mount 4 moves on the straight line C in FIG. The cam 12 rotates within one rotation, and the first lens group 1A and the second lens group
The lens group 1B is moved to the positional relationship shown by straight line A and curved line B in FIG. In other words, the second lens group supporting barrel 9 is shaped by the shape of the cam 12 and the roller 16.
The distance between the first and second lens groups 1A and 1B is maintained at an inter-lens distance corresponding to the magnification ratio. Therefore, the magnification change by the zoom lens 1 is stepless as long as the pedestal 4 is moved steplessly.

Accordingly, the present invention uses the zoom lens 1 described above to perform limited magnification change in multiple steps, and the drive source of the zoom lens mount 4 is the motor 20 with a speed reducer. This motor 20 uses a known mechanism such as a worm wheel mechanism as a speed reducer, and has a function of suppressing free rotation of the output shaft when the motor is stopped, but has a position for detecting the rotational position of the output shaft. It does not have a detection function. A pulley 21 located near one end of the guide rod 3 is provided on the output shaft of the motor 20.
and a pulley 2 located near the other end of the guide rod 3.
A wire 23 is stretched between the two. The wire 23 is wound several times around the pulley 21 to prevent it from slipping, and both ends of the wire 23 are wrapped around the pulley 21 with tension coil springs 24.
It is connected to the pedestal 4 via a and 24b. Therefore, when the motor 20 is rotated forward or backward, the pedestal 4 moves along the guide rod 3.

The movement position of the frame 4 is detected by pulleys 21 and 22.
A slit plate 25 fixed to the base 2 parallel to the wire 23 between the wires 23 stretched on the
When pressed by the transmission type sensor 27 supported on the pedestal 4 and the end face 4a of the pedestal 4, which emits a matching signal when the position matches the position detection slits 26A, 26B, and 26C drilled in the slit plate 25. This is done by means of an origin detector 28 consisting of a microswitch that is closed. In this embodiment, the origin detector 28 is located at one end of the movement of the frame 4, that is, when the zoom lens 1 is at the second reduction position (high reduction amount position).
(nearby) is detected, and the slit 26A,
In 26B and 26C, the pedestal 4 is at the reduced position (low reduction amount position) (nearby) and at the same magnification position (nearby), respectively.
It is provided to detect whether the

The mechanical stopper device 30 that receives detection signals from the transmission type sensor 27 and the origin detector 28 to stop the pedestal 4 at each magnification position includes a stopper plate 31 fixed on the base 2, and a stopper plate 31 fixed on the base 2.
A lock release plate 33 is superimposed on the stopper plate 31 and moves on the stopper plate 31 by excitation and demagnetization of the solenoid 32.
It has The stopper plate 31 and the lock release plate 33 are provided parallel to the guide rod 3, and the stopper plate 31 is provided with a mount 4 as shown in detail in FIG.
Abutment surfaces 31A, 31B, and 31C corresponding to the first reduction position, the same magnification position, and the enlargement position are provided, and an abutment surface 31D corresponding to the second reduction position is further provided. These contact surfaces engage with a stopper roller 36 at the tip of a stopper arm 35 that is pivotally supported on the pedestal 4 by a pin 34 to regulate the position of the pedestal 4.
The stopper arm 35 is biased to swing by a tension spring 37 so as to deeply engage with the abutment surfaces 31A to 31D. The abutting surfaces 31A to 31C are all provided to prevent the pedestal 4 from moving to the left in FIG. It is provided to prevent movement in the right direction (towards the photoreceptor).

The lock release plate 33 is an intermediate contact surface 3 excluding the contact surfaces 31C and 31D at both ends of the stopper plate 31.
Inclined lock release surface 33 corresponding to 1A, 31B
A, has 33B. This lock release surface 33A,
33B does not protrude above the contact surfaces 31A and 31B when the release plate 33 is pulled to one sliding end by the tension spring 38 when the solenoid 32 is demagnetized, but when the solenoid 32 is energized. When the release plate 33 is pulled to the other sliding end, the contact surface 31
A, 31B so that the stopper roller 36 at the tip of the arm 35 escapes from the corresponding contact surface 31A, 31B (or the stopper roller 36
A, 31B).

As mentioned above, the contact surface 31A of the stopper plate 31,
31B and 31C are for regulating the moving end of the pedestal 4 on the left side in FIG. 3, so these contact surfaces 31A,
In order to control the position of the pedestal 4 by bringing the stopper roller 36 into contact with 31B and 31C, the pedestal 4 is moved to the right side (photosensitive surface side) from these abutting surfaces. To do this, regardless of the position of the pedestal 4, when the power is turned on, or when the pedestal 4 is detected to the left (original side) of the selected magnification, the pedestal 4 must be moved by its stopper roller 36. It is preferable to return it until it comes into contact with the contact surface 31D (reduction position 2). This return operation is performed by rotating the pulley 21 counterclockwise in FIG. 3 by the motor 20. As shown in the chart of FIG.
It operates x amount before contacting D and turns off the power to the motor 20. The pedestal 4 moves x amount by the inertia of the motor 20 to bring the stopper roller 36 into contact with the contact surface 31D, and the motor 20 moves the wire 23 and the pedestal 4 by an amount x.
The tension spring 24a tensioned between the pulley 21 and the pulley 21 is stretched, and the pulley 21 stops when the tension force of the spring and the force trying to rotate the pulley 21 are balanced.

Thereafter, in order to move the pedestal 4 to the reduced position (abutment surface 31A), the pulley 21 (motor 20) may be rotated clockwise in FIG. 3. Immediately before the stopper roller 36 contacts the abutment surface 31A (x amount before), the transmission type sensor 27 and the position detection slit 26A detect this, turn off the power to the motor 20, and move the pedestal 4 to the reduced position in the same manner as above. Position.

In addition, in order to move the pedestal 4 to the same magnification position (abutting surface 31B) or the enlarged position (31C), the solenoid 32 is energized at the same time as the pulley 21 (motor 20) is rotated clockwise in FIG. The transmission type sensor 27 is connected to the position detection slit 26B or 26
When C is detected, the motor 20 may be stopped and the solenoid 32 may be demagnetized. By energizing the solenoid 32, the release surfaces 33A, 33B of the lock release plate 33 project above the contact surfaces 31A, 31B, allowing the stopper roller 36 to ride over the corresponding contact surfaces 31A, 31B. The sensor 27 turns off the power to the motor 20 and the solenoid 32 just before the stopper roller 36 comes into contact with the contact surface 31B or 31C (x amount before), as in other stop positions.
The frame 4 is stopped at a predetermined position. Furthermore, motor 2
0 has a speed reducer, so that the pulley 21, which is its output shaft, does not spin idly even if it receives the force of the tension springs 24a and 24b, and the pedestal 4 is reliably positioned at each magnification.

Next, FIGS. 7 and 8 show specific examples of control of the magnification changing device. In this example, considering that the 1x position is used most frequently, the zoom lens 1 (mount 4) is unconditionally moved to the 1x position when the power is turned on, and then moved to each set magnification using the selection switch. This is what I did.

() Movement when the power is turned on (1) If the zoom lens 1 (mount 4) is at the second reduction position (origin position), it moves to the same magnification position as shown by line A in FIG.

(2) If the zoom lens 1 is located in a region other than the 1x magnification position, it returns to the original position and then moves to the 1x magnification position, as shown in B and C in the diagram.

() Moving the set magnification When moving the zoom lens 1 from the current position to the document surface side, or when moving to the reduction 2 position (origin position), move the zoom lens 1 directly to the selected magnification position, and then move the zoom lens 1 from the current position to the If it is possible to move closer to the photosensitive surface, the principle is to return to the original position and then move to the selected magnification position.

Therefore, taking as an example the case where the zoom lens 1 is at the same magnification position, (3) it moves directly to the enlargement position and the reduction position as shown in the diagram D and H.

(4) To reduce the position, as shown in the diagram, it returns to the origin position and then moves.

Next, referring to FIG. 9, a block circuit for achieving the above movements () and () will be explained. In the figure, a motor 20, a magnification detector (transmission type sensor) 27, an origin detector 28, and a solenoid 3
2 is the same component as described above, and the detection signal 28A from the origin detector 28 is input to the CPU 41 via the receiver 40. If the zoom lens 1 is at the origin position (reduction position 2) when the power is turned on, the origin detector 28 detects this and inputs it to the CPU 41, and the CPU 41 controls the motor 20 in the clockwise direction (reduction position 2) via the processing circuit 42. Figure 3) At the same time as the rotation signal 20A is issued, the solenoid 32
An excitation signal 32A is generated via the receiver 43. As a result, the mount 4 (zoom lens 1) starts moving to the same magnification position, and when it reaches the same magnification position, the slit detection signal 27A sent from the magnification detector 27 via the receiver 44 causes the CPU 41 to rotate the motor clockwise. Turn off signal 20A and solenoid excitation signal 32A. The CPU 41 counts the number of slits based on the slit detection signal 27A, and detects that the zoom lens 1 has moved to the same magnification position.

If the zoom lens 1 is located in a region other than the same magnification position when the power is turned on, the origin detector 28 issues a non-detection signal 28B, and the CPU 41 uses this signal to issue a counterclockwise rotation signal 20B to the motor 20. , simultaneously issues an excitation signal 32A to the solenoid 32. As a result, the zoom lens 1 moves to the home position, and when the home position detector 28 detects this, the signal 20B turns OFF, and at the same time, the clockwise rotation signal 20A is generated. The subsequent operation is the same as described above, and the zoom lens 1 stops at the same magnification position.

The CPU 41 stores the number of count slits corresponding to each magnification position detected by the magnification detector 27 using the magnification detection slits 26A to 26C, and later sends a magnification change signal 45A to the magnification switch 45 via the receiver 46. When given, the number of set count slits corresponding to each magnification is compared with the number of stored count slits, and a signal is generated.

To simplify the explanation, we will assume that the number of memory count slits and the number of set count slits at the reduced position, normal size position, and enlarged position are ``1'', ``2'', and ``2'', respectively.
If it is set to "3", even if the equal magnification setting switch is pressed when the zoom lens 1 is at the equal magnification position, both count slit numbers are the same and the calculation result is zero, so the motor 20 does not rotate. That is, the zoom lens 1 is maintained at the same position. This also applies to other set magnifications.

If you operate the magnification switch when zoom lens 1 is at the same magnification position, (number of count slits set) -
The calculation result of (memory count slit number) is positive, and as a result, the motor clockwise rotation signal is 20A.
Then, the solenoid excitation signal 32A is generated, and the zoom lens 1 moves to the enlarged position side. When the magnification detector 27 detects the slit 26C, the motor clockwise rotation signal 20A and the solenoid excitation signal 32A are turned OFF, and the zoom lens 1 stops at the enlarged position.

When the magnification change switch is operated from the same magnification position to the reduction 1st position or reduction 2nd position, the above calculation result will be negative, and in this case, the motor counterclockwise rotation signal 20B will cause
The zoom lens 1 is unconditionally returned to the second reduction position (origin position). When the reduction-2 position is selected, the zoom lens stops at this origin position, and when the reduction-position is selected, the motor clockwise rotation signal 20A and the solenoid excitation are triggered by the detection signal from the origin detector 28. A signal 32A is issued, and the zoom lens 1 starts moving toward the document surface again. When the magnification detector 27 detects the position detection slit 26A, the motor signal 20A and the solenoid signal 32A are turned OFF, and as a result, the zoom lens 1 stops at the first reduction position.

The above is a case in which the zoom lens 1 is moved from the same magnification position to each magnification position, but movement between other magnification positions is also performed in the same manner as described above. In the above embodiment, the two reduced positions are set as the origin position, but the enlarged position may be set as the origin position. In this case, the mechanical stopper device may be used with the left and right sides of the figure reversed.

In summary, the present invention provides a copying machine that uses a zoom lens to change the magnification while maintaining a constant distance between objects and images. Since the stopper plate provided along with the stopper roller is provided with an abutment surface that engages with the stopper roller to stop the zoom lens at a predetermined magnification position, the zoom lens can be stopped at an accurate copying magnification position. . Further, a lock release plate having an inclined lock release surface is superimposed on the stopper plate, and when unlocking is necessary, by moving this lock release plate, the stopper roller is moved from the abutting surface by the inclined lock release surface. can be moved to the release position. Therefore, it is possible to smoothly and reliably stop the zoom lens at multiple copying magnification positions and move it from one stop position to the next. Moreover, this movement control requires no expensive numerically controlled motor. does not require

[Brief explanation of drawings]

1 and 2 are lens movement state diagrams showing the optical principle of magnification changing by a zoom lens, FIG. 3 is a plan view showing an embodiment of the magnification changing position of a copying machine according to the present invention, and FIG. 5 is a plan view of the mechanical stopper device, FIG. 6 is a timing chart showing the relationship between the mechanical stopper device and the sensor, and FIG. 7 is a diagram of the copying machine of the present invention. FIG. 8 is a flowchart showing an example of control of the zoom lens, FIG. 8 is a diagram showing an example of the movement locus of the zoom lens, and FIG. 9 is a block diagram of the control circuit. DESCRIPTION OF SYMBOLS 1... Zoom lens, 2... Base, 3... Guide rod, 4... Zoom lens mount, 20... Motor with reducer, 21, 22... Pulley, 23... Wire, 25... Slit plate, 26A, 26B, 26
C...Position detection slit, 27...Transmission type sensor, 28...Origin detector, 30...Mechanical stopper device, 31A, 31B, 31C, 31D...Abutment surface, 32...Solenoid, 33... Lock release plate, 33A, 33B... Inclined lock release surface, 36
...Stopparola, 41...CPU, 45...
Magnification switch.

Claims (1)

[Claims] 1. In a variable magnification device of a copying machine that changes the copying magnification by moving the zoom lens between the document surface and the photoreceptor, a stopper plate arranged along the moving direction of the zoom lens; , a plurality of abutment surfaces corresponding to a plurality of copying magnification positions; a stopper arm pivotally connected to the zoom lens mount supporting the zoom lens; a stopper roller provided at the free end of the stopper arm; a biasing means for rotationally biasing the stopper roller in a direction to engage with the abutting surface of the stopper plate; a lock release plate superimposed on the stopper plate and movable in the longitudinal direction of the stopper plate; a sloped lock release surface formed on the plate corresponding to an intermediate contact surface excluding both ends of the stopper plate; this lock release plate is normally held in a position where the sloped lock release surface does not engage with the stopper roller; a holding means; a lock release plate drive which moves the lock release plate on the stopper plate and uses its inclined lock release surface to separate the stopper roller from the abutment surface of the stopper plate against the biasing means of the stopper arm; A variable magnification device for a copying machine, characterized by comprising a mechanism.