JPH0792618B2 - Copier with variable magnification function - Google Patents

Description

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

<Prior Art> Generally, many copiers perform copying in accordance with 1: 1 of a document, but some copiers have a reduction or enlargement function. As the reduction or enlargement function, at least two elements of the document holder, the optical system, and the photoconductor may be moved to change the positions. However, the photoconductor is generally formed in a drum shape and cannot move. It is also very difficult to change the position of the document holder. Therefore, conventionally, a copying machine which can be reduced or enlarged has been realized by changing the position of the optical system located between the document holding portion and the photoconductor.

<Problems to be Solved by the Invention> A copying machine having a variable magnification function enables reduction or enlargement copying by changing the position of the optical system described above. However, conventionally, when the optical system is moved according to the set magnification, a detection means such as a micro switch is arranged at a position corresponding to each magnification, and the movement of the optical system is performed in response to a detection signal of this detection means. Have control. For example, Japanese Patent Application No. 52-163880 (Japanese Patent Application No. 54-9022) which is a prior application of the present invention.
No. 5) clarifies this in detail.

However, the detection means such as a micro switch may have a very small number of variable bulk magnifications, but if it has a large number, the detection means corresponding to the number must be arranged at a predetermined position, which is very troublesome. On the other hand, it is very difficult to dispose a large number of optical systems on the path that moves according to the magnification because of the problem of bulkiness. Further, in the detection means such as a micro switch, there is a problem of its responsiveness, so that 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 can accurately move an optical system according to a set magnification without using a detection means such as a micro switch and can cope with any magnification. A copier is provided.

<Means for Solving the Problem> In a copying machine with a variable magnification function according to the present invention, an optical system arranged between a document and a photoconductor is moved according to a set magnification, and a document image is formed on the photoconductor. In a copier with a variable magnification function that forms an image in accordance with a set magnification, a drive motor that rotates in forward and reverse directions in order to connect the optical system and move it to a position according to the set magnification. A movement amount output means for outputting the movement amount indicating the movement position of the optical system according to the set magnification with reference to the equal-magnification position, and a rotation amount for moving the optical system in a proportional relationship by the drive motor. Rotation amount output means, comparison means for inputting and comparing respective outputs from the movement amount output means and the rotation amount output means, and a non-coincidence output by the comparison means for driving the drive motor in the forward or reverse direction to drive the optical system. Move one A control means for stopping the drive motor in response to the output.

<Operation> According to the copying machine of the present invention, the amount of movement for moving the optical system to the position of the set magnification is output according to the set copying magnification with reference to the position of equal magnification. If this output does not match the output due to the rotation amount of the drive motor that moves the optical system, the direction corresponding to it, for example, the drive motor is normally or reversely rotated. The output corresponding to the amount of rotation by the driving of the motor continues until it matches the amount of movement of the optical system, and then stops. In particular, since the rotation amount of the drive motor is output in proportion to the movement amount of the optical system, the optical system is moved to the set copy magnification position only by stopping the drive motor with the coincidence signal from the comparison means. You can move exactly.

In particular, the same magnification is set as the reference position in the optical system, and the movement amount of each set magnification corresponding to this reference position is output.
When adjusting the output, if the output at the reference position is constant, for example, set to "0", the rotation amount by the drive motor can also be adjusted by initial setting as "0". The adjustment allows for accurate positioning of the optical system thereafter.

<Embodiment> First, before describing an embodiment of the present invention, the principle of the reduction or enlargement function will be described.

Referring to FIG. 1, this FIG. 1 shows a state in which an object 1 is magnified into an image having a size of l ′ through a lens L having a focal length f. Considering that the lens L is a thin lens, the distance between the principal points is zero, and the center of the lens L is O. When the distance from the object 1 to the center O of the lens L is a, the distance from the center O of the lens L to the image l'is b, and the magnification of the image l'is m, 1 / a + 1 / b = 1 / f ... … (1) m = 1 ′ / l = b / a …… (2) a = f (1 + 1 / m) …… (3) b = f (1 + m) …… (4) It is already well known that Has been.

Therefore, when a fixed focus lens is used, it is necessary to change a and b in order to change the magnification m. 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 that the above a + b becomes the minimum is a = b, that is,
In the case of equal size (1; 1), when reducing or expanding,
It can be seen that a + b increases as the magnification m increases.

Next, referring to FIG. 2 for the above relationship, the relationship between the amount of movement of the optical system and the magnification will be clarified. In the case of the same size in the figure, assuming that the reflection mirror 1 and the lens 2 are at the positions shown by solid lines, the distance a from the document surface 3 to the lens 2 via the reflection mirror 1 and the lens 2 to the working surface (photosensitive surface) ) Distance to 4 b
And are in the relationship of a = b = 2f. Therefore, if the lens 2 is moved to the right by x and the reflecting mirror 1 is moved to the left by y as indicated by the dotted line, the distance from the document surface 3 to the lens 3 is increased by x + y. Therefore, the lens 2 of the optical system
And the movement amounts x and y of the reflection mirror 1 are (3)
From the equation (4), x = 2f−f (1 + m) = f (1-m) (5) y = a + b−4f = f (1 + 1 / m) + f (1 + m) −4f = f / m · (m ² −2m + 1) = f / m · (m-1) ² (6) By substituting the desired magnification m in the above equation, the amount of movement of x and y of the optical system to be moved is calculated.

For _{example, B 5, A 4, B} 4 , etc. are most often used as the size of the document and paper. Therefore, Table 1 below shows an example of the magnification when copying to the paper of the above size.

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

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

Next, an example of the optical system portion of the present invention will be described with reference to FIG. In the figure, reference numeral 10 denotes an original holding surface made of a transparent member for holding an original, which is movably provided, for example. This is a so-called manuscript table moving type copying machine. Reference numeral 11 denotes a drum-shaped photosensitive member on which an image of the original document on the holding surface is formed by the optical system 12, and is rotated in the arrow direction.

Although not shown, an apparatus for image formation is arranged on the peripheral surface of the photoconductor 11. That is, the surface of the photoconductor 11 is uniformly charged before the image exposure by the optical system 12, and the image is exposed by the optical system 12. As a result, an electrostatic latent image corresponding to the image of the original is formed on the photoconductor 11. This latent image is visualized as a toner image by the developing device, and this toner image is transferred to the fed copy paper by the action of transfer means or the like. Then, the copy sheet onto which the toner image has been transferred is peeled off from the photoconductor 11 and sent to the 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, the residual toner on the photoconductor 11 is removed by a cleaning device to prepare for the next image formation.

The optical system 12 for performing the image exposure described above includes a light source 13 for illuminating an original on the holding surface 10, a reflection mirror 14 for guiding an optical image from the original to a moving mirror 15, and an optical image from the original on a photoreceptor 11. Moving lens 16 for forming an image, and two fixed mirrors provided between the lens 16 and the photoconductor 11 to form an optical image on the photoconductor 11.
It consists of 17,18. If the moving mirror 15 and the lens 16 are moved according to the magnification m in the above optical system 12,
It is possible to perform reduction or enlargement copying at an arbitrary magnification m.
In the example of FIG. 3, the x and y movement amounts are as described in FIG. 2, but the moving lens 16 has an optical axis inclination θ, and the moving mirror 15 has the reflecting mirror of FIG. It should be taken into consideration that the amount of movement will be 1/2.

In the present invention having the above-described structure, in order to set the magnification, for example, the size of the document on the holding surface 10 is detected, and the entire image of the document is used by this size detection and the copy paper size used. Magnification m for copying on copy paper
An example of automatically setting will be described.

Therefore, as a device for detecting the size of the document, for example, the device shown in FIG. 4 can be considered. This detecting device is provided on a document cover 19 for bringing the document into close contact with a document holding surface 10 provided on the main body of the copying machine, corresponding to the documents of different sizes on which the light receiving elements 20 are mounted. Further, 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,
The size of the document held on the holding surface 10 can be detected according to the light receiving state of each light receiving element 20 provided on the document cover 19. The lamp 21 is controlled by a micro switch 22 provided so as to face one side edge of the original cover 19, and the original cover 19 covers the holding surface 10, whereby the lamp 21 is turned on. The lamp 21 is configured to be turned off by turning on the light source 13 of the optical system. The size of the document can be detected as described above.

FIGS. 5A and 5B are for explaining an example for detecting the size of the copy sheet. In the figure,
A cassette 23 containing copy paper on one end of the copying machine body
Is detachably attached to the paper feed port 24. The paper feed port 24 is provided with a micro switch 25 for detecting the size of the cassette 23 when the cassette 23 is mounted.
On the other hand, protrusions 26 are provided on the cassette 23 side so as to face the microswitches 25. For example cassette 23
The Assuming that A ₄ size copy sheet is accommodated, the projections
26 _-2 is provided with, at the time of mounting of the cassette microswitch 25 _-2 ON, and detects that a copy paper A ₄ size. Further, if the size is B ₄ , the projection 26 _-1 is provided on the cassette 23, and if it is the B ₅ size, the projection 26 _-3 is provided on the cassette 23.
Micro switches 25 _-1 , 25 corresponding to protrusions 26 _-1 , 26 _-3
-3 turns on and detects copy paper of each size. The size of the copy paper is detected as described above, but if the width of each paper is different, the micro switch or the photodetector is arranged according to each width in the paper feed path to detect the paper size. You may.

FIG. 6 shows the moving mirror 15 and the moving lens described in FIG.
FIG. 16 is a perspective view showing a moving mechanism of 16. In the figure, 27 and 28 are movable plates 29 and 30 that fixedly hold the movable lens 16 and the movable mirror 15.
Is a guide shaft for moving. This guide shaft 27,2
The frame 8 is rotatably held by the frame 31, and a pulley to which the rotational force from the motors 32 and 33 is transmitted via the belts 34 and 35 is fixed to one end. In addition, the guide shaft 27,2
8 is threaded and screwed onto this screw to move plate 29,
30 are provided. Therefore, when the motors 32 and 33 rotate, they are transmitted to the guide shafts 27 and 28, and the moving plates 29 and 30 move.
Therefore, the movable lens 16, which is fixedly held by the movable plates 29 and 30,
The moving mirror 15 is moved in the x and y directions. Where motor 3
Reference numeral 2 is a moving servo motor for the moving lens 16, and motor 33 is a moving servo motor for the moving mirror 16. Moreover, a potentiometer is connected to the rotation shafts of the servomotors 32 and 33 to represent the rotation amount of the motor, that is, the driving amount. That is, the drive amounts of the servomotors 32 and 33 are obtained by accurately adjusting the moving lens 16 and the moving mirror 15 to the moving amount of the magnification m by the output from the potentiometer. The moving lens and mirror moving mechanism shown in FIG. 6 is moved by rotating the guide shaft, but the moving plate may be pulled and moved by a wire or belt.
The moving mechanism of the present invention is not limited to that shown in FIG.

Further, FIG. 7 is a block diagram showing a circuit configuration for performing movement control of the optical system of FIG. In this figure, 36
Is an input control circuit for automatically setting the magnification based on the size signals from the document size detecting apparatus and the paper size detecting apparatus described in FIGS. 4 and 5, and outputting the set magnification m. The signal of the set magnification m from the input control circuit 36 is introduced to the arithmetic circuits 37 and 39 which output the movement amount according to the magnification of the next optical system. By inputting the magnification m, the arithmetic circuits 37 and 39 arithmetically output the movement amount of the optical system according to the above equations (5) and (6). For example, a moving lens
In order to obtain the movement amount x of 16, the arithmetic circuit 27 calculates f (1-m) according to the input set magnification m, and the arithmetic circuit 38 calculates the moving mirror 15 of the input set magnification m. The calculation of f / m · (m−1) is performed to output the movement amount y. That is, the arithmetic circuit is movement amount output means for outputting 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 according to the tilted angle θ. Further, in the mirror 15, 1 / the movement amount by the above equation
It is necessary to correct the movement amount to 2. However, the method of obtaining the correction amount is not related to the present invention, and therefore its explanation is omitted. If no correction is required, the optical system may be configured as shown in FIG.

In each of the arithmetic circuits 37 and 38, the moving lens 16 and the moving mirror 1
When the moving amounts x and y of 5 are calculated and output, this output value is input to the positive (+) or negative (−) input terminal of each of the comparison circuits 39 to 42. The other positive (+) or negative (-) input terminals of the comparison circuits 39 to 42 are supplied with signals (voltage) from potentiometers 43 and 44 connected to the rotation shafts of the servomotors 32 and 33. There is. That is, the comparison circuits 39 and 40 are
The movement amount x from 7 is compared with the voltage value related to the rotation amount of the servo motor 32 from the potentiometer 43, and the comparison output for rotating the servo motor 32 by any method is used as a transistor 45, which is a motor drive circuit. In addition to 46 base terminals. Here, the potentiometer 43 sets the “0” potential to the position x = 0 of the lens 16, that is, the equal magnification position, as shown in FIG. 8, and is proportional to the movement amount of the lens 16 and corresponds to the rotation amount of the motor. Rotation amount output means for performing the above output. As shown in FIG. 8, the optical system, that is, the same magnification of the lens position is used as a reference position, and the movement amount at that time is "0" and the rotation amount of the servo motor 32 is "0". Therefore, by performing the output adjustment at the same-magnification position, the adjustment of the initial setting can be set so as to become the predetermined reference value “0”, which is very easy. Moreover, since the rotation amount of the servo motor 32 and the movement amount of the optical system are output in a proportional relationship in accordance with each magnification, the outputs are compared with each other so that the optical position is set to a position corresponding to an arbitrary copying magnification set. The system, that is, the lens, can be accurately positioned. Further, the potentiometer 44 has the same configuration as the potentiometer 43.

Therefore, if the output from the comparator circuit 39 (negative), the transistor 45 is turned ON, the servo motor 32 is the negative voltage -V _M 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 rotation, tends to be negative. Therefore, when the value of the movement amount x from the arithmetic circuit 37 and the voltage value from the potentiometer 43 match, the output from the comparison circuit 39 is lost and the rotation of the motor 32 is stopped. That is, the moving lens 16 moves to a position corresponding to the magnification m and is held at that position. Conversely, if a positive output from the comparator circuit 30 in accordance with the set magnification m, the positive voltage + V _M is supplied to the servo motor 32 rotates in the aforementioned opposite direction, moving the lens 16 in the left direction It is moved to a position according to the magnification m.

On the other hand, the comparison circuits 41 and 42 compare the value of the movement amount y from the arithmetic circuit 38 with the voltage value from the potentiometer 44, and add the comparison output to the base terminals of the transistors 47 and 48. Therefore, if the value of the movement amount y of the arithmetic circuit 38 is smaller than the value of the potentiometer 44, there is an output from the comparison circuit 41 and the transistor 47 is turned on. Thus, the negative voltage -V _M is applied to the servo motor 33, the motor 33 is rotated in a direction to move the movable mirror 15 in the right direction. Then, when the input difference of the comparison circuit 41 becomes “0”, the rotation of the motor 33 stops. That is, the moving mirror 15 moves to a position matching the magnification m and stops at that position. Conversely, if the amount of movement y from the arithmetic circuit 38 is larger than the value of the potentiometer 44,
There is a positive output from the comparator circuit 42. As a result, the motor rotates in the opposite direction to the above, moves the moving mirror 15 to a position matching the magnification m, and stops.

As described above, the movement amount of the optical system is output according to the set magnification m, the motor for moving the optical system is drive-controlled according to the movement amount, and the optical system is moved to the position corresponding to the magnification m. When it moves and stops, the document surface 10 moves in FIG. 3, and an image of the document corresponding to the magnification m is formed on the photoconductor 11. At this time, the moving speed of the photoconductor 11 or the document surface 10 is changed according to the above-mentioned magnification m.

<Effect> As described above, according to the present invention, the rotation amount of the drive motor for moving the optical system and the movement amount of the optical system according to the copy magnification are output in a proportional relationship, and the comparison result is obtained. The motor drive control is performed accordingly, and accurate positioning can be performed without arranging a large number of position detection switches, etc. in the movement path of the optical system.Therefore, the optical system can be placed at a position according to the arbitrarily set copy magnification. It is possible to perform accurate positioning and, for example, to continuously change the copy magnification.

Moreover, by adjusting the output of the movement amount and the rotation amount with the same magnification as the reference position, the positioning adjustment of the optical system can be easily and accurately performed. In particular, since the enlargement and reduction are performed based on the same size, the error can be reduced in any case.

[Brief description of drawings]

1 and 2 are used to explain the relationship of the magnification of the present invention, FIG. 3 is a sectional view showing the details of the optical system portion of the copying machine of the present invention, and FIG. 4 is the original size detection. FIG. 5A and FIG. 5B are sectional views showing a specific example for detecting the cassette size, and FIG. 5A is a front view showing the cassette mounting portion on the copying machine main body side. Figure,
6B is a perspective view showing a cassette, FIG. 6 is a perspective view showing an example of a moving mechanism of an optical system for moving the optical system for varying the magnification of the present invention, and FIG. 7 is an optical system of the present invention. FIG. 8 is a block diagram showing the configuration of a control circuit for controlling the movement amount of the motor, and FIG. 8 is a diagram showing the movement relationship between the potentiometer showing the rotation amount of the motor and the optical system. 10; original holding surface, 11; photoconductor, 12; optical system, 15; moving mirror, 16; moving lens 29; moving plate holding moving lens 30; moving plate holding moving mirror 32; moving lens driving servo Motor 33; Servo motor for driving the moving mirror 36; Input control means 37 for outputting a set magnification; Calculation circuit 38 for outputting the movement amount of the moving lens 38; Calculation circuits for outputting the movement amount of the moving mirror 39 to 42: Comparison circuit 43 , 44; Potentiometer 45 to 48; Transistor for motor drive

Claims (1)

[Claims] 1. A variable magnification function, wherein an optical system disposed between a document and a photoconductor is moved according to a set magnification to form a document image on the photoconductor according to the set magnification. In a copying machine, a drive motor that rotates in forward and reverse directions to move the optical system to a position according to a set magnification and a moving position of the optical system according to the set magnification are shown. A movement amount output means for outputting the movement amount with reference to the 1x position, a rotation amount output means for outputting a rotation amount for moving the optical system in a proportional relationship by the drive motor, the movement amount output means and the rotation amount. A comparison means for inputting and comparing each output from the output means, and a non-coincidence output by the comparison means to drive the drive motor forward or reversely to move the optical system, and stop the drive motor in response to the coincidence output. Control means to Comprising a variable magnification function copier comprising by varying depending on any rate set.