JPH0373976A - Copying machine with variable magnification function - Google Patents

Abstract

PURPOSE:To handle optional magnification by comparing the movement set quantity of an optical system corresponding to set magnification with the driving quantity of a driving means and controlling the driving means for an optical system. CONSTITUTION:A signal of the set magnification (m) from an input control circuit 36 is inputted to arithmetic circuits 37 and 38 which outputs a movement quantity according to next magnification of the optical system and thus the magnification (m) is inputted to calculated and output the movement quantity of the optical system. Comparing circuits 39-42 compares set movement quanti ties from the arithmetic circuits 37 and 38 with voltage values regarding the driving quantities of servomotors 32 and 33 which are received from potentiometers 43 and 44 and send comparison outputs for rotating the servomotors 32 and 33 in one direction to base terminals of transistors 45-48 constituting motor driving circuits. Consequently, the optical system can be moved accurately to a position corresponding to optional magnification (m).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Technical Field> The present invention relates to a copying machine equipped with a variable magnification function capable of reducing and enlarging.

<Prior Art> In general, most copying machines perform I:1 copying of original documents, but some copying machines also have a reduction or enlargement function. The reduction or enlargement function may be achieved by moving at least two of the document holder, the optical system, and the photoreceptor to change their positions.

However, the photoreceptor is generally formed into a drum shape and cannot be moved. It is also very difficult to change the position of the document holding section. Therefore, in the past, a copying machine that can be reduced or enlarged has been realized by changing the position of the optical system located between the document holder and the photoreceptor.

<Problems to be Solved by the Invention> A copying machine equipped with a variable magnification function is capable of reducing or enlarging copies by changing the position of the above-mentioned optical system. However, conventionally, when moving an optical system according to a set magnification, a detection means such as a microswitch is placed at a position corresponding to each magnification, and the optical system is moved in response to a detection signal from this detection means. It's in control. For example, this is specified in detail in Utility Model Application No. 163880/1980 (Kokai No. 90225/1983), which is an earlier application of the present invention.

However, detection means such as microswitches are extremely bulky, and while it is sufficient if the number of variable magnifications is small, if there are many, detection means corresponding to the number must be placed at predetermined positions, which is extremely troublesome. Furthermore, it is extremely difficult to arrange a large number of optical systems along the path that moves them according to the magnification due to the problem of bulk. Furthermore, in detection means such as microswitches, there is a problem in their responsiveness, and accurate movement of the optical system cannot be expected.

In view of the above-mentioned problems, the present invention has a variable magnification function that allows the optical system to be accurately moved according to a set magnification without using a detection means such as a microswitch, and can also handle any magnification. It provides copying machines.

<Means for Solving the Problems> A copying machine with a variable magnification function of the present invention moves an optical system disposed between an original and a photoreceptor according to a set magnification, and displays an image of the original on the photoreceptor. A copying machine with a variable magnification function that forms an image according to a set magnification, a driving means for moving the optical system according to the set magnification, and an amount of movement of the optical system according to the set magnification. a movement amount output means for outputting the amount of drive by the drive means; a comparison means for inputting and comparing each output from the movement amount output means and the drive amount output means; The present invention is characterized by comprising a control means for operating the driving means to move the optical system in response to a mismatch output, and stopping the drive means in response to a coincidence output.

<Operation> According to the copying machine of the present invention, the optical system is moved by comparing the amount of movement of the optical system according to the set magnification with the amount of drive of the drive means related to the movement of the optical system. It controls the drive means to make it move.

In other words, the amount of movement of the optical system according to the set magnification is compared with the amount of movement of the optical system by the driving means, and the driving means moves the optical system until a match is found, and responds to the detection of a match. The driving means is stopped. As a result, the optical system is moved to a position corresponding to the set magnification. In this case, it is sufficient to output the amount of movement of the optical system according to the set magnification, and it is possible to correspond to any magnification, and there is no need to arrange a detection means such as a microswitch on the path along which the optical system is moved.

<Example> First, before explaining the present invention in detail, the principle of the reduction or enlargement function will be explained.

Referring to Fig. 1, in this Fig. 1, the subject C has a focal length M
It shows a state in which the magnification is changed to an image having a size e' through a lens L f. The above lens is considered to be a thin lens, the distance between the principal points is zero, and the center of the lens L is O. Then, the distance from the subject Q to the center O of the lens L is a1 The distance from the center O of the lens L to the image Q' is b1 The magnification of the image g' is m, then 1/a+1/b=1/f e a 6 (1) m=Q'
/Q = b/a* e e e e (2) a=f
(1+1/m) $ 6 @ e (3) b=f(
1+m) ... It is already well known that the result is (4).

Therefore, when using a fixed focus lens, changing the magnification m requires changing a and b. Therefore, it will be understood that it is necessary to move two or more elements among the document holder, the optical system, and the document described above.

Therefore, the condition for the minimum a+b is a=b, that is,
In the case of equal magnification (1:1), when reducing or enlarging, it can be seen that a+b increases as the magnification m increases.

Next, with reference to FIG. 2, the relationship between the amount of movement of the optical system and the magnification will be clarified. In the figure, if the reflection mirror 1 and lens 2 are at the positions indicated by solid lines in the case of the same magnification, then the distance Mh from the document surface 3 to the lens 2 via the reflection mirror l, and the distance Mh from the lens 2 to the working surface (photosensitive surface). )4 is in the relationship a=b=2f. Therefore, as shown by the dotted line, lens 2 moves by X to the right, and reflective mirror 1 moves y to the left.
If the distance from the document surface 3 to the lens 3 is increased by x+y, respectively. Therefore, the respective movement amounts X and y of the lens 2 and reflection mirror 1 of the optical system are (3X
4) From formula, x=2f-f(14m)=f(1-m)・(5)y=
a+b-4f = f (1+1/m)+f (14
m) -4f=f/m(m'-2m+1) -f/m(m-1)''...(6).If the desired magnification m is substituted in the above equation, the optical system's The amount of movement in X and y to be moved is calculated.

For example, as the size of the manuscript and paper, B s , A
4.

B4 etc. are most commonly used. Therefore, Table 1 below shows an example of the magnification when copying onto paper of the above-mentioned size.

Table 1 As described above, Table 1 shows the magnification in the relationship between document size and paper size. Although it can be set at any magnification limited to the above-mentioned set magnification, the amount of movement of the optical system according to the set magnification m can be easily determined from equations (5) and (6) above. By moving the optical system according to the amount of movement, it is possible to deal with any magnification m.

The present invention is a copying machine that can perform variable magnification copying, either reduction or enlargement, by utilizing the above-mentioned relationship.

Next, an example of the optical system portion of the present invention will be explained with reference to FIG. In the figure, reference numeral 10 denotes a document holding surface that is cut out from a transparent member that holds a document, and is provided movably, for example. This is a so-called document table moving type copying machine.

Reference numeral 11 denotes a drum-shaped photoreceptor on which an image of a document on a holding surface is formed by an optical system 12, and is rotated in the direction of the arrow.

On the circumferential surface of the photoreceptor 11, an image forming device (not shown) is arranged. That is, the surface of the photoreceptor 11 is uniformly charged before being subjected to image exposure by the optical system 12, and is subjected to image exposure by the optical system t2. As a result, an electrostatic latent image corresponding to the image of the document is formed on the photoreceptor 11. This latent image is visualized as a toner image by a developing device, and this toner image is transferred onto a fed copy sheet by the action of a transfer means or the like. The copy paper onto which the toner image has been transferred is then peeled off from the photoreceptor 11 and sent to a fixing section, where the toner image is fixed as a permanent image and then discharged to the outside of the copying machine. On the other hand, residual toner on the photoreceptor 11 is removed by a cleaning device, and the photoreceptor 11 is prepared for the next image formation.

The optical system 12 for performing the image exposure includes a light source 13 that illuminates the document on the holding surface 10, a reflection mirror 14 that guides the light image from the document to a moving mirror 15, and a photoreceptor 12 that directs the light image from the document to a photoreceptor.
It is composed of a movable lens 16 for forming an image on the photoreceptor 11, and two fixed mirrors 17 and 18 provided between the lens 16 and the photoreceptor 11 for forming an optical image on the photoreceptor 11. In the optical system 12 described above, the movable mirror 15 is moved according to the magnification m.
By moving the lens 16, it is possible to perform reduction or enlargement copying with an arbitrary magnification m. In addition, in the example of Figure 3,
The amount of movement in each x and y is as explained in Fig. 2, but
It is sufficient to take into consideration that the moving lens 16 has an optical axis tilt θ and the moving mirror 15 has a movement amount that is 1/2 that of the reflecting mirror in FIG.

In the above configuration, the present invention detects the size of the document on the holding surface IO, for example, in order to set the magnification, and uses the entire image of the document based on this size detection and the copy paper size to be used. An example will be explained in which the magnification m for copying on copy paper is automatically set.

Therefore, a device for detecting the size of the original may be one shown in FIG. 4, for example. This detection device is provided with a light-receiving element 20 corresponding to each document of different size on a document cover 19 that brings the document into close contact with a document retaining surface 10 provided on the copying machine main body 2. Also, the holding surface lO
A lamp 21 is provided on the lower surface of the holding surface 10 so as not to interfere with the illumination of the document on the holding surface 10 by the light source 13 shown in FIG. Therefore, depending on the light receiving state of each light receiving element 20 provided on the document cover 19, the size of the document held on the holding surface IO can be detected. The lamp 21 is controlled by a microswitch 22 provided opposite to one side edge of the document cover 19, and the lamp 21 is turned on when the document force/(-19 covers the holding surface IO. 2I is configured to be turned off when the light source 13 of the optical system is turned on.The size of the document can be detected as described above.

FIG. 5 (a>(b) is for explaining an example for detecting the size of copy paper. In this figure,
At one end of the copying machine body is a cassette 2 containing copy paper.
3 is detachably attached to the paper feeder 24.

This paper feed port 24 is provided with a microswitch 25 for detecting the size of the cassette 23 when the cassette 23 is attached.

On the other hand, protrusions 26 are provided on the cassette 23 side facing each of the microswitches 25, respectively.

For example, if the cassette 23 stores A4 size copy paper, a protrusion 26-3 is provided, and when the cassette is installed, the microswitch 25- is ONL,
It is detected that the copy paper is A4 size. Also, B
If the size is B, the protrusion 26-8 is provided on the cassette 23, and if the size is B, the protrusion 26-8 is provided on the cassette 23.
-1.26-1 corresponding to each microswitch 25-.
.

25-8 is ONL, which detects copy paper of each size. The size of copy paper is detected as described above, but if each paper has a different width, a microswitch or a photodetector is placed in the paper feed path according to the valley width to detect the paper size. May be detected.

FIG. 6 is a perspective view showing a mechanism for moving the movable mirror 15 and the movable lens 16 described in FIG. 3.

In the figure, 27 and 28 are the movable lens 16 and the movable mirror 15.
This is a guide shaft for moving the movable plates 29 and 30 that are fixedly held. This guide shaft 27°28 is connected to the frame 3
1 and a motor 32 at one end.
, 33 is fixed thereto, through which the rotational forces from the belts 34, 35 are transmitted. In addition, the guide shaft 27.2
8 is threaded, and each movable plate 2 is screwed onto this screw.
9°30 is provided. Therefore, the motors 32, 33
When the rotation occurs, it is transmitted to the guide shafts 27 and 28, and the moving plate 2
9.30 moves. Therefore, the movable lens 16 and the movable mirror 15 fixedly held on the movable plate 29.degree. 30 are moved in the x and y directions. Here, the motor 32 is connected to the movable lens 1
The moving servo motor 6, the motor 33 is the moving mirror 16.
This is a servo motor for movement. Moreover, a potentiometer is connected to the rotating shaft of each servo motor 32, 33 to indicate the amount of rotation of the motor, that is, the amount of drive. That is, the amount of drive of the servo motors 32 and 33 is obtained by adjusting the amount of movement of the movable lens 16 and the movable mirror 15 precisely to the amount of movement of the magnification m by the output from the potentiometer. Although the moving lens and mirror moving mechanism shown in FIG. 6 is moved by rotating the guide shaft, a structure in which the moving plate is pulled by a wire or a belt, etc., and moved may also be used.
The moving mechanism of the present invention is not limited to that shown in FIG.

Furthermore, FIG. 7 is a block diagram showing a circuit configuration for controlling the movement of the optical system shown in FIG. 6. In this figure, 3
Reference numeral 6 denotes an input control circuit that automatically sets a magnification based on each size signal from the document size detection device and paper size detection device described in FIGS. 4 and 5, and outputs the set magnification m. The signal of the set magnification m from the input control circuit 36 is introduced into an arithmetic circuit 37, 39 which outputs the amount of movement according to the magnification of the next optical system. This arithmetic circuit 37
．． 39, by inputting the magnification m, - the above equation (5)
And according to (6), the amount of movement of the optical system is calculated and output. For example, in order to obtain the movement Mix of the moving lens 16, the arithmetic circuit 37 calculates f(1-m
), and the calculation circuit 38 calculates the setting magnification m manually.
i,: In order to output the movement amount y of the movable mirror 15, f/m·(m-1) is calculated. In other words, the above-mentioned control circuit is a movement amount output means that outputs the movement amount of the optical system.

Here, when the lens 16 is tilted by θ with respect to the optical axis as shown in FIG. 3, correction is required in accordance with the tilted angle θ. Further, in the mirror 15, it is necessary to correct the movement amount according to the above formula to 1/2. However, since the method of determining the correction amount is not very relevant to the present invention, its explanation will be omitted. If no correction is required, the optical system may be configured as shown in FIG.

The above calculation circuits 37 and 38 calculate and output the movement amounts X and y of the movable lens 16 and the movable mirror 15, and these output values are input to the positive (+) or negative (=) of each comparison circuit 39 to 42. entered at the end. The other positive (+) or negative (-) input terminal of the comparison circuits 39 to 42 is connected to the servo motor 3.
2. Potentiometer 43 connected to the rotating shaft of 33.
A signal (voltage) from 44 is applied. In other words, the comparison circuits 39 and 40 compare the amount of movement X from the arithmetic circuit 37 with the voltage value related to the amount of drive of the servo motor 32 from the potentiometer 43, and calculate the voltage value for rotating the servo motor 32 in either direction. The comparison output is applied to the base terminal of transistor 45.46 which is a motor drive circuit. Here, as shown in FIG. 8, the potentiometer 43 sets the "0" potential to the position x = 0 of the lens 16, that is, the same magnification position, and the rotation of the motor is determined by the movement amount of the lens 16 and the relationship l:I. This is a drive amount output means that outputs the amount, that is, the drive amount. Note that the same applies to the potentiometer 44.

Therefore, if there is an output (negative) from the comparator circuit 39, the transistor 45 is ONL, and the negative voltage -VM is applied to the servo motor 32.
is added. For example, the lens 16 shown in FIG. 3 is moved to the right. As the motor 32 rotates,
The potential of the potentiometer 43, which is the amount of drive thereof, tends to be negative. Therefore, if the value of the movement fix from the arithmetic circuit 37 and the voltage value from the potentiometer 43 match, the output from the comparison circuit 39 disappears and the rotation of the motor 32 is stopped. That is, the movable lens 16 is moved to a position corresponding to the magnification m and is held at that position. On the other hand, if there is a positive output from the comparator circuit 30 according to the set magnification m, a positive voltage +VM is supplied to the servo motor 32, which rotates in the opposite direction to the above, and the movable lens 16 moves to the left to increase the magnification. It is moved to a position corresponding to m.

On the other hand, the comparison circuits 41 and 42 compare the value of the movement amount y from the arithmetic circuit 38 and the voltage value from the potentiometer 44, and apply the comparison output to the base terminal of each transistor 47 and 48. Therefore, if the value of the moving amount y of the arithmetic circuit 38 is smaller than the value of the potentiometer 44, there is an output from the comparator circuit 41, and the range meta 4f is turned on.

As a result, a negative voltage -VN is applied to the servo motor 33, and the motor 33 rotates in a direction that moves the movable mirror 15 to the right. Then, the difference in human power of the comparison circuit 41 is “
0", the motor 33 stops rotating. That is, the movable mirror I5 moves to a position matching the magnification m and stops at that position. Conversely, the moving amount y from the calculation circuit 38 is
If it is larger than the value of the potentiometer 44, the comparator circuit 4
There is a more positive output than 2. As a result, the motor rotates in the opposite direction to that described above, moves the moving mirror 15 to a position matching the magnification m, and stops.

As described above, the amount of movement of the optical system is output according to the set magnification m, and the motor that moves the optical system is driven and controlled according to the amount of movement, and the optical system is moved to the position corresponding to the magnification m. If it moves and stops, the original surface 10 in FIG.
moves, and an image of the document according to the magnification m is formed on the photoreceptor 11. At this time, the moving speed of the photoreceptor 11 or the document surface 10 is varied according to the above-mentioned magnification m.

Effect> As explained above, according to the copying machine of the present invention, the drive unit outputs the amount of movement of the optical system according to the set magnification m, and moves the optical system according to the amount of movement. Therefore, the optical system can be accurately moved to a position corresponding to the magnification m using a very simple configuration.

In this case, the path for moving the optical system has its magnification m
Accurate movement control can be performed without arranging a detection means or the like at a position corresponding to the position.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams provided to explain the relationship between magnifications of the present invention, FIG. 3 is a sectional view showing details of the optical system portion of the copying machine according to the present invention, and FIG. 4 is a diagram showing document size detection. 5(a) and (b) are cross-sectional views showing a specific example for detecting the cassette size.
a) is a front view showing the cassette mounting part on the copying machine main body side;
b) is a perspective view showing a cassette, FIG. 6 is a perspective view showing an example of an optical system moving mechanism for moving the optical system to vary the magnification of the present invention, and FIG. 7 is a perspective view showing movement of the optical system of the present invention. FIG. 8 is a block diagram showing the configuration of a control circuit for controlling the amount of rotation. FIG. 8 is a diagram showing the movement relationship between a potentiometer indicating the amount of rotation of the motor and the optical system. lO; Original holding surface 11; Photoreceptor 12: Optical system 15
; Moving mirror 16; Moving lens 29; Moving plate 30 holding a moving lens; Moving plate 32 holding a moving mirror; Servo motor 33 for driving a moving lens; Servo motor 36 for driving a moving mirror; Input control for outputting a set magnification Means 37; Arithmetic circuit 38 for outputting the amount of movement of the moving lens; Arithmetic circuits 39 to 42 for outputting the amount of movement of the moving mirror; Comparison circuits 43, 44; Potentiometer

Claims (1)

[Claims of Claims] 1. Variable image forming system in which an optical system placed between the original and the photoconductor is moved according to the set magnification, and the original image is formed on the photoconductor according to the set magnification. In a copying machine with a magnification function, a driving means for moving the optical system according to a set magnification, a movement amount output means for outputting a moving amount of the optical system according to the set magnification, and the driving means a drive amount output means for outputting a drive amount by the drive amount; a comparison means for inputting and comparing each output from the movement amount output means and the drive amount output means; and an optical system for operating the drive means based on the discrepancy output from the comparison means. and control means for moving the driving means and stopping the driving means in response to a coincidence output, the copying machine having a variable magnification function capable of varying the magnification according to an arbitrary set magnification.