JPS5917406B2 - Copying device with variable copy magnification - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying apparatus with variable copying magnification, and more particularly, to a copying apparatus with variable copying magnification, which is provided with first and second reflecting means that scan an original by traveling at a speed ratio of 1 H. The present invention relates to a copying apparatus.

A copying apparatus is known that optically scans an original to be copied using first and second reflecting means running at a speed ratio of 1:H, and exposes a movable photosensitive member with a light image of the original using a so-called slit. .

The reason why the first and second reflecting means are run at a speed ratio of 1 H is to keep the optical path length between the imaging lens and the document constant during the scanning period. On the other hand, let a be the optical path length between the main plane of the imaging lens and the original, let be the optical path length between the main plane of the imaging lens and the photoreceptor at the exposure position, and let f be the focal length of the imaging lens. In this case, if the formula 1/a+1/b=1/f holds true, an original optical image with a magnification of m is formed on the photoreceptor. Here m
-b/a. If we express a, , b using m and f, then a
=(m+1)f/m, b=(m+1)f. And a+b(m+1)2f/m.

As is clear from the above, when determining the copying magnification, the optical path length A. b, (a+b) must be changed.

For example, when changing the copy magnification from m to Mc, the optical path length A,
．． b, (a+b) is a+△A. b+△b, (a+b)+
It can be changed to Δ(a+b). Here △a: (m-Mc)
f/MmcΔb: (Mcm)f1Δ(a+b)=(Mc
-m)(Mmc-1)f/Mmc. As mentioned above,
In a copying apparatus equipped with a scanning optical system consisting of first and second reflecting means that move at a scanning ratio of 1:%, when converting the copying magnification, it is common practice to change the position of the imaging lens and to change the scanning optical system. The optical path length can be changed by adjusting the optical system.

That is, the optical path length b is changed by changing the position of the imaging lens, and the optical path length a, (a+b) is changed by adjusting the scanning optical system at the same time as the position adjustment of the imaging lens. This brings about a new conjugate relationship between the original and the photoreceptor. For example, when switching from 1x copying to 0.7x copying, optical path length a must be increased by 3f/7, but optical path length b only needs to be shortened by 3f/10. The first one running at a speed ratio of 1:% as described above.
, a second reflecting means, and a variable copying magnification are known.

For example, US Pat.
No. 914044 discloses that the position of the second reflecting means is selected by displacing one end of a wire wound around a movable pulley for causing the second reflecting means to run at a speed that is % of that of the first reflecting means. A copying apparatus is disclosed that can be changed to a position corresponding to a copying magnification.

In such a device, in order to prevent the wire from becoming loose due to displacement of one end of the wire when changing the copying magnification,
It is essential to keep the end of the wire taut at all times with an elastic means such as a spring. Therefore, such devices have a small degree of freedom in device design, and each time the copying magnification is changed, the tension of the spring, etc. applied to the end of the wire changes, which tends to make the scanning of the original unstable. There is a disadvantage that the durability of the device is inferior. The above-mentioned elastic means for preventing the wire from loosening when changing the copying magnification was disclosed in Japanese Patent Publication No. 51-1983.
This is not necessary in the copying apparatus described in Publication No. 34731. However, the apparatus disclosed in the same publication moves a pulley that displaces the second reflecting means to a position corresponding to the selected copying magnification by substantially simultaneously displacing substantially both ends of the wire to the first and second reflecting means. When moving forward or backward for document scanning, a special mechanism is also required to resist the rotational driving force received from the wire and stop the rotation. SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to provide a variable magnification copying device which overcomes the drawbacks of the previously mentioned known devices.

Another object of the invention is to provide a first,
To provide a copying apparatus having a simple mechanism capable of easily and accurately adjusting a document scanning optical system including a second reflecting means when converting copying magnification.

Still another object of the present invention is to provide a copying apparatus equipped with a magnification changing mechanism in which the tension applied to the wire-like member for running the reflecting means does not change even if the copying magnification is changed.

Still another object of the present invention is to provide a variable magnification copying apparatus that can stably scan an original at any copying magnification.

Still another object of the present invention is to provide a variable magnification copying device in which no unreasonable force is applied to the magnification conversion mechanism when moving the first and second reflecting means forward or backward in order to scan a document. It is to be.

Still another object of the present invention is to provide a variable magnification copying apparatus in which the tension applied to the wire member remains unchanged even if the distance between the first and second reflecting means is changed. Still another object of the present invention is to provide a copying apparatus which enables adjustment of an original scanning optical system for copying magnification conversion without displacing the substantial locking end of a wire-like member for running a reflecting means with respect to the main body of the apparatus. The goal is to provide the following.

Further objects, structural features, and effects of the present invention will become clear from the following description.

FIG. 1 shows a copying apparatus to which the present invention can be applied, in which a conductive base layer,
A drum 2 having a photoreceptor 1 on its circumferential surface formed by laminating a photoconductive layer and a transparent surface insulating layer in this order is supported at a predetermined position in the apparatus,
It is rotated at a constant speed in the direction of the arrow by an electric motor (not shown).

The rotational speed of the drum 2 is the same for any copying magnification. The surface of the photoreceptor 1 is first coated with D. C. It is uniformly charged by the corona discharger 3. Next, the photoreceptor 1 is subjected to slit exposure of a light image of the original to be copied by an optical system to be described later, and at the same time, the photoreceptor 1 is subjected to slitting exposure of a light image of the original to be copied. C. Or D. of polarity opposite to that of the discharger 3. C
．． Receives corona discharge from corona discharger 4. The discharge vessel 4 is provided with a slit opening through which the imaging light flux passes. Photoreceptor 1 is then uniformly illuminated over its entire surface by lamp 5, thereby forming a high contrast electrostatic latent image of the document. This latent image is transferred to the photoreceptor 1 by a developing device 6 such as a magnetic brush type.
Developed by supplying toner to. The obtained visible toner image is transferred to a transfer paper 7 that is fed at the same speed as the circumferential speed of the drum 2 while receiving a discharge of opposite polarity to the toner charge on the back side by a corona discharger 8 in order to increase transfer efficiency. . The transfer paper is taken out from a force set (not shown) in synchronization with the rotation of the drum one by one, brought into contact with the photoreceptor 1 via a guide 9, and then peeled off from the photoreceptor by a claw 10. Transfer paper transport mechanisms are well known. The toner image carried on the transfer paper 7 is fixed by a fixing device 11 such as a heating roller type. On the other hand, the toner remaining on the surface of the photoreceptor 1 after the transfer is removed by a cleaning device 12 such as a rubber blade pressed against the photoreceptor, and the photoreceptor 1 returned to a clean surface is again subjected to the image forming process. Injected. The original to be copied 0 is placed in a stationary state on a transparent flat plate-like original table 13.

The document table 13 is fixed to an immovable member 14 such as a side plate of the main body of the copying apparatus, and is immovable. The above original is the first mirror 15, the second mirror
Scanning is performed by a scanning optical system consisting of a mirror 16. That is,
The first and second mirrors 15 and 16 move in the direction of the arrow in synchronization with the rotation of the drum 2 when exposing the photoconductor 1 with a light image of the original.
That is, it travels in a direction parallel to the document table 13. 1st mirror 1
The speed 5 is the speed obtained by multiplying the peripheral speed of the drum 2, that is, the peripheral speed of the photoreceptor 1, by the reciprocal of the copying magnification, that is, the imaging magnification of the imaging lens 17. Therefore, when making a full-size copy (each mirror and lens are arranged at the solid line position in the figure, the lens 17
(When the optical path length from the document side is equal to the optical path length from the lens 17 to the photoconductor side), the first mirror 15 travels at the same speed as the circumferential speed of the photoconductor 1. The speed of the second mirror 16 is half the speed of the first mirror 15. First and second mirrors 15, 16
The speed ratio is 1:%, and by running in parallel in the same direction, the optical path length between the lens 17 and the document is kept constant. When the scanning optical system has finished scanning the document 0 from one end to the other, that is, the mirrors 15 and 16 are 15 and 16 as shown in the figure.
Noi Jun? When reached, mirrors 15 and 16 stop traveling,
Next, it moves in the opposite direction to the original scanning direction and returns to the home position (positions indicated by solid lines 15 and 16).

The home position is the starting position of the mirror when it repeatedly moves back and forth to scan a document, and the position where the mirror starts moving back and stops. The lamp 18 and the concave mirror 19 arranged behind it are supported integrally with the first mirror 15 by a support body (not shown).
It is designed to run together with the 5.

The lamp 18 is turned on only when the first mirror 15 moves forward, and works together with the concave mirror 19 to illuminate the document 0. The light reflected from the original 0 is reflected by the first mirror 15 and then reflected by the second mirror 1.
6, and then reflected by the second mirror 16 in a direction substantially opposite to the direction of incidence and directed toward the imaging lens 17.
The imaging light flux exiting the lens 17 is sequentially reflected by the third and fourth mirrors 20 and 21 fixed at fixed positions, and then enters the photoreceptor 1 as described above. In addition, the lens located at the solid line 17 in FIG.
It is assumed that the image is formed on the top. That is, the optical path length A. Both b are 2f. When converting the copy magnification, the lens 17 is displaced, for example, along the optical axis by an amount corresponding to the selected copy magnification m, and the first
Copy magnification m selected with mirror 15 parallel to document table 13
Displace the amount corresponding to .

That is, the lens 17 and the first mirror 15 are moved to positions corresponding to the selected copying magnification m, and the optical path length A. Let b be (m+1)f/m and (m+1)f, respectively. When m is smaller than 1, that is, when performing reduced copying, the first
As shown in the figure, the first mirror 15 is moved to the position of the broken line 15'', and the lens 17 is moved to the position of the broken line 1r.In other words, both the first mirror 15 and the lens 17 are moved to the position of the second mirror 16''.
They are each displaced by a predetermined amount in the direction away from. In the embodiment of FIG. 1, the third and fourth mirrors 20 and 21 are fixed at fixed positions, so the amount of displacement of the lens 1r is {2f-(m+1)f
}, that is, (1-m)f. Therefore, the first mirror 15
The displacement amount is [(m+1)f/m{2t+(1-m)f}
] That is, (m-1)2f/m.

When m is larger than 1, that is, in an enlarged copying apparatus, the first mirror 15 and the imaging lens 1 are
7 are respectively changed in the direction approaching the second mirror 16 by an amount corresponding to the magnification m. FIG. 2 shows an example of a driving means for driving the first and second mirrors 15 and 16.

Reference numeral 22 denotes a guide rail fixed to a side plate or the like of the main body of the apparatus.

The guide rail 22 is arranged parallel to the document table 13, and the first
, guides the movement of the second mirrors 15 and 16. That is, the first
The mirror 15 and the lamp 18, the leg part 231 of the first support body 23 to which the reflecting mirror 19 is fixed, and the front and rear leg parts 241 and 242 of the second support body 24 to which the second mirror 16 is fixed, respectively. They are slidably fitted into the guide rail 22 so as not to interfere with each other. First support body 23, second support body 24
is made to reciprocate along the guide rail 22 by applying the principle of a movable pulley. Note that the first support body and the second support body can also be supported and guided by separate guide rails. 25 is the second
This is a pulley that is rotatably provided on a shaft 251 fixed to the leg portion 242 of the support and is movable integrally with the second mirror 16 .

26 is a drive pulley fixed to a shaft 261 that receives the rotational force of an electric motor (described later) via a forward rotation clutch or a reverse rotation clutch (described later) to rotate forward or reverse, and does not rotate when both clutches are not in operation. be.

The drive pulley 26 is disposed at a fixed position that is further displaced in the forward movement direction from the end point of the forward movement of the movable pulley 25.
27 is rotatably disposed on a shaft 271 fixed at a fixed position that is further displaced in the forward movement direction than the end point of the forward movement of the point where the wire is fixed to the leg portion of the first support 23 (described later). It's a pulley.

Reference numerals 28 and 29 denote pulleys for variable magnification operation which are independently rotatably provided on the shaft 30, as shown in FIG.

As shown in FIG. 3, the pulleys 28 and 29 are fitted with ball bearings 281 and 2 that are rotatably fitted to the shaft 30, respectively.
91. The shaft 30 is therefore connected to the pulley 28,
29 indicates that no matter where pulley 25 is located, pulley 2
5 and pulley 27, and between pulley 25 and pulley 26. The shaft 30, and therefore the pulleys 28 and 29, are displaced parallel to the guide rail 22 within a predetermined distance range by an amount corresponding to the magnification selected by the magnification conversion operation. When switching from full size copying to m times reduced copying, the pulleys 28 and 29 are displaced by (m-1)2f/2m from the solid line position to the broken line position in the figure.
On the other hand, when switching from reduced copying to full size copying, the pulleys 28 and 29 are displaced from the broken line position to the solid line position. In other words, pulleys 28 and 29 are moved in the same direction by the copying magnification conversion operation and are integrally moved to a position corresponding to the selected magnification. Reference numeral 31 denotes a wire fixing member that is placed at a fixed position on the side opposite to the pulley 26 with respect to the pulley 28, no matter where the pulley 28 is located.

A wire 32 for moving the first and second mirrors 15 and 16 forward for document scanning is fixed at one end to a drive pulley 26 and wound multiple times, and is wound around the second pulley 26 for magnification conversion.
9. It is sequentially suspended by the fixed position pulley 27, the movable pulley 25, and the first magnification conversion pulley 28, and the other end is connected to the fixed position member 31 by a screw 311. And between the pulleys 25 and 27, the wire 32 is connected to the first mirror support 2.
It is fixed to the leg 231 of No. 3 by a fixing member 232. In the example of FIG. 2, wire 32 runs substantially parallel to guide rail 22 between each pulley and between pulley 30 and member 31, and extends substantially parallel to each other to pulleys 28 and 30. It's being pulled from the opposite direction. Photoreceptor 1
When scanning a document to form an electrostatic latent image on the image, the forward rotation clutch described above is operated to rotate the drive pulley 26 at a speed substantially equal to the circumferential speed of the photoreceptor 1 multiplied by the reciprocal of the copying magnification. Then, the pulley 26 winds up the wire 32 at the above-mentioned speed, causing the first and second mirrors 15 and 16 to move forward at the above-mentioned speed.

That is, the wire 32 is caused to run while pulling the first support member 23 through the fixed point, and is pulled while rotating the movable pulley 25 to move the second support member 24 at a speed of % of that of the first support member. Run it with At this time, pulleys 27 and 29 are also rotating, but pulley 28 is not rotating. Pulley 28, 29
The support shaft 30 is stationary at a position corresponding to the set magnification. The following mechanism is used in FIG. 2 to return the first and second mirrors 15 and 16 to their respective starting positions after scanning the original.

That is, one drive pulley 26 is attached to the rotation shaft 261 of the drive pulley.
A pulley 33 with a diameter half that of is fixed. That is, the pulley 33 rotates in the same direction at a peripheral speed that is % of the peripheral speed of the pulley 26. On the other hand, the pulley 34 is rotatably supported by a shaft 341 fixed at a fixed position on the side opposite to the pulley 33 with respect to the pulley 25 . One end of the wire 35 is wound around the pulley 33 in the opposite direction to the direction in which it is wound around the pulley 26, the end is fixed to the pulley 33, and the wire 35 is wound several times, and then it is suspended around the pulley 34, and then the other end is Second support leg 2
42 with a fixing member 243. That is, the wire 35 is stretched from the direction opposite to the direction in which the wire 32 is stretched to the pulley 25 with respect to the second support body 24, and the wire 35 is stretched between the members 243 and 34 so that the wire 35 is substantially connected to the guide rail 22. is parallel to If the drive pulley 26 rotates normally, the pulley 3
3 also rotates in the normal direction to let out the wire 35 that is pulled by the leg 242. When the aforementioned reversing clutch is actuated, the pulley 33 winds up the wire 35 and causes the second support 24 to move back. At this time, the pulley 25 rotates and pulls the wire 32, and the pulley 26 rotates in the opposite direction to feed out the corresponding amount of wire, so that the first support body 23 also moves backward. 1st mirror 15
, the backward movement speed ratio of the second mirror 16 is also 1:%. Note that even when the mirror is moving back, the pulleys 27 and 29 rotate, but the pulley 28 does not rotate, and the shaft 30 remains stationary at a position corresponding to the copying magnification. In FIG. 2, the pulley 33 is provided coaxially with the pulley 26, but the pulley 33 may be provided as a separate shaft so that the rotational force of the shaft 261 is transmitted through a gear train or the like. Alternatively, the pulley 33 may be rotated by a drive means separate from the pulley 26. The key is to unwind the wire 35 at half the speed of the winding and unwinding speed of the wire 32 on the pulley 26, and to rotate the pulley 33 to wind it. When converting the copying magnification from normal to reduced, the shaft 30 and therefore the pulleys 28 and 29 are moved from the solid line position to the broken line position in FIG. 2, as described above.

At this time, the pulley 26 has stopped rotating. Pulley 28,
By displacing 29 as described above, the pulleys 25,
The wire 32 is pulled toward the pulley 27 between the pulleys 27 and 27, and the wire 32 is pulled toward the pulley 25 between the pulleys 25 and 28. The first support 23 and thus the first mirror 15 are therefore displaced in the direction away from the second mirror 16. At this time, pulleys 25, 27, 28, and 29 rotate, and pulleys 26, 33, and 34 do not rotate. The first mirror 16
The amount of displacement is as described above. And pulley 28,
Even after changing the position of the mirror 29, the first and second mirrors 15, 16
The operations of each member for forward and backward movement are as described above, except that the rotational speed of the shaft 261 is converted to a speed corresponding to the selected copying magnification. It should be noted that although the rotational direction of each pulley was not specifically explained in the example shown in FIG. 2 or in the other embodiments, those skilled in the art will understand this from the above or subsequent explanation of the configuration. As described above, the wires are suspended between both ends of the first and second mirror reciprocating wires 32 from substantially opposite directions, and are rotatably provided independently of each other on the same support member. Since the variable magnification operation is achieved by changing the positions of the pulleys 28 and 29, the tension of the wire 32 does not change even with this variable magnification operation.

Further, since the first mirror 15 is displaced by the above-mentioned magnification changing operation, very accurate optical path length conversion can be easily achieved.
FIG. 4 shows an example of a displacement mechanism for the zoom pulleys 28, 29 and the lens 17. A shaft 30 rotatably supporting pulleys 28 and 29 is fixed to a shaft support 301. The shaft support 301 is parallel to the tensioning direction of the wire 32 with respect to the pulleys 28 and 29, so in this case, the mirror guide rail 2
It is slidably supported by a guide rail 302 provided in parallel to 2. On the other hand, the imaging lens 17 is coupled to a lens support 171, and this lens support 17
1 is slidably supported by a guide rail 172 provided parallel to the optical axis of the lens 17, for example. The guide rail 172 may be oriented so that the lens 17 can be displaced in directions having vector components in the optical axis direction and the rotation axis direction of the photosensitive drum 2, respectively. This allows one end of images of various magnifications to be aligned with a fixed position at the end of the photoreceptor. Each of the guide rails 172, 302 has a support 171, 301 at each end thereof in contact with an end of the corresponding support 171, 301.
A convex portion is provided to stop the movement of. Guide rail 172
, 302, corresponding supports 171, 301, respectively.
When they come into contact with each other, the imaging lens 17 and the first mirror 15 are positioned at positions corresponding to the set copying magnification. The lens support 171 and the shaft support 301 have one end fixed to the support 171, 301, and the other end fixed to an immovable member such as a beam of the main body of the apparatus, that is, a tension spring 173 fixed in a fixed position.
303, corresponding guide rails 172 and 302, respectively.
is biased in the direction of overflowing. Furthermore, the lens support 17
1. One ends of wires 174 and 304 are fixed to the side opposite to the spring engagement side of the shaft support 301, respectively. wire 1
74 and 304 are respectively suspended by pulleys 175 and 305 which are rotatably arranged at fixed positions, and each end is connected to the lever 36.
is attached to the end of the The lever 36 is rotatably supported within a predetermined angular range by a shaft 361 fixed at a fixed position, that is, to an immovable member of the main body of the apparatus. Shaft 361 and wire 1
The length of the lever to the fixing point of 74, the shaft 361 and the wire 3
The ratio of the lever length to the fixed point of 04 is (1-m)f:
(m-1)2. f/2m. By rotating the lever 36 about the shaft 361 when changing the copying magnification, the supports 171, 301 and thus the lens 17 and the shaft 30 can be brought to a position corresponding to the selected magnification. This is performed by a cam 363 fixed to a shaft 362 that receives the rotational force of an electric motor 364 activated by the rotation of the lever 36 and makes a half turn at a fixed position for each magnification conversion operation. The cam 363 is in pressure contact with the lever 36. In the state shown in FIG. 4, the lens 17 and first mirror 15 are in the solid line positions in FIG. 1, and therefore the pulleys 28 and 29 are in the solid line positions in FIG.

When the motor 364 is activated and the cam 363 is rotated half a turn, the lever 36 rotates and the supports 171, 301 are pulled by the springs 173, 303, respectively, so that the supports 171, 301 are moved against the rails 172, 30.
2 and move to the specified position. That is, the pulley 28,
29 moves to the dashed line position in FIG. 2, and therefore the first mirror 15
is at the dashed line position 15' in Figure 1, and the lens is also at the dashed line position 17'.
Move to. To displace the lens and the first mirror again, the motor 364 may be operated to rotate the cam 363 by half a turn again. In FIG. 5, MS1, 2, 3, and 4 are micro switches arranged along the mirror guide rail 22. In FIG.

The distance between the microswitches MS1 and MS2 is set to correspond to the maximum width of the document that can be copied. When the first mirror 15 is at the home position for document scanning, the microswitches MSl and MS4 are activated by the actuating member 233 of the support body 23.
, 234, respectively, are microswitches MS.
2 are respectively disposed at positions where the actuating member 233 of the support body 23 comes into contact when the first mirror 15 scans to the end of the document and reaches the folding position. Also micro switch MS
3 is disposed at a position where the operating member 233 of the first support body 23 that moves when the pulleys 28 and 29 are returned from the dashed line position to the solid line position comes into contact. The above micro switch MSl
, 3, and 4 have contacts that close when the support 23 comes into contact with them, while microswitch MS2 opens the contacts when the support 23 comes into contact with them. Before explaining the control circuit, a brief explanation of the embodiment shown in FIG. 5 will be given. By the copying magnification conversion operation, the position of the imaging lens 17 is changed by the means shown in FIG. 4, and the pulley 28, Displace 29.

Now, when converting from a full size copy to a reduced copy, the pulleys 28 and 29 are moved from the solid line position in the direction of arrow A1 to the broken line positions 28' and 29' in FIG. As described above, this causes the first mirror support 23 to move in the direction of arrow A2 from the solid line position to the broken line position 23'. In this embodiment, from this state, by pressing the copy button, the pulleys 26, 33 are rotated in the direction of arrow A3, and the pulley 26, 33 is rotated in the direction of arrow A3.
At the same time, the wire 32 is let out, the wire 35 is wound around the pulley 33, and the first mirror support 23 is moved from the broken line position 23' in the direction of arrow A4, and is once returned to the position where it contacts the micro switch MS1. At the same time, the pulley 25 and therefore the support 24 of the second mirror also move in the direction of arrow A5, and when the support 23 stops, it moves to the position 25'' indicated by the broken line.
, 24'. The amount of displacement of the pulley 25 and the support body 24 in the direction of arrow A5, that is, the amount of displacement of the second mirror 16, is the amount of displacement of the support body 23 in the direction of the arrow circle, that is, the amount of displacement of the first mirror 15. It's half. Note that the support 2
During the displacement to the document scanning start position of 3 and 24, the pulleys 29, 27, 25, and 34 rotate, but the pulley 28 does not rotate. The pulleys 28 and 29 remain stopped at the positions indicated by the broken lines in the figure. Next, when converting to a same size copy after completing the reduced copy, move the pulleys 28 and 29 to the dashed line positions 28' and 29.
' to move in the direction of arrow A6 and displace to the solid line position. At this time, the first support body 23 moves in the direction of arrow A7 along the guide rail 22 and is displaced from the solid line position to the dashed line position 23''5.At this time, the pulley 25 and the second support body 24 are moved to the dashed line position. It is stationary at 25'' and 24'. When the copy button is pressed in this state, the pulleys 26 and 33 are rotated in the direction of arrow A8 by the action of micro switch MS3, and the first support 23 and second support 24 are rotated in the directions of arrows A, A, and O, respectively. Move and return to the solid line position. At this time, pulley 29 rotates, pulley 28 does not rotate, and pulleys 28, 29
does not move from the solid line position. When the first support 23 and the second support 24 return to their respective solid line positions, that is, the home positions, the lamp 18 is turned on by the action of the micro switch MS4, and at the same time, by the action of the micro switch MSl,
The first and second supports 24 then begin to travel for document scanning. By doing the above, the home position of the second mirror 16 changes depending on the copying magnification conversion, but the home position of the first mirror 15, which directly faces the original, can be made the same for any copying magnification. , the alignment position of the scanning start end of the original on the original platen 13 can be made the same for any copying magnification.

However, if the first mirror is displaced by the magnification change operation and returned to the single predetermined home position as described above, in other words, the home position of the second mirror corresponds to the selected copying magnification. When the light is changed, the position of the optical axis of the lens 17, which is sequentially reflected by the second and first mirrors 16 and 15 and enters the document table 13, is displaced, as shown in FIG. In FIG. 6, 16' indicates the home position of the second mirror when the copying magnification is changed from normal to reduced. X1 is the optical axis for full size copying, and X2 is the optical axis for reduced copying. Although there is a distance between X1 and X2, problems caused by this can be easily solved. That is, in general, there is a so-called pre-travel distance between the home position of the first mirror, and therefore the second mirror, and the positions where each mirror optically faces the end of the document on the scanning start side. ing. This is done by causing the first and second mirrors to travel in advance before the start of document scanning, and at the time the document scanning is started, the first and second mirrors are
This is to ensure that the mirrors are stable at their respective predetermined constant speeds, but because this pre-travel section is provided, when the magnification change operation is performed, the first mirror is kept at the same speed. Even if the position of the optical axis is displaced as described above with respect to the home position of , the scanning start side end of the document is not located within the displacement range of the optical axis. Of course, before and after the scaling operation,
Even if the first mirror is moved to the same home position, the distance between the optical axis and the end of the document on the scanning start side changes due to the optical axis displacement. However, this distance variation is required for the optical axis at each copying magnification to move between the position when the first mirror is in the home position and the position when the scan initiator end of the document is reached. This can be easily corrected by changing the timing at which the transfer paper 7 is fed to the transfer section in FIG. 1 in accordance with the time, in other words, the pretravel time of the optical axis facing the set copying magnification. In other words, by changing the timing at which the transfer paper 7 starts contacting the photoreceptor 1 in accordance with the copying magnification conversion, even if the optical axis is displaced as X1 and X2 as described above, the leading edge of the original image can be copied. Inconveniences such as not being transferred or the leading edge of the original image being displaced backward from the leading edge of the transfer paper can be easily solved. In addition to the above-mentioned optical axis displacement, the reason why the forward travel time of the optical axis changes due to the conversion of the copying magnification is the first,
This is also due to the fact that the required running speed of the second mirror is converted in accordance with the copying magnification. The paper feeding timing is set in accordance with each copying magnification by combining these two factors. Such paper feeding timing control may include, for example, a timer, etc., in which a set time length is controlled by a copying magnification setting operation means, and a time point at which the above-mentioned transfer paper conveying means starts operating in accordance with the set time length. This can be achieved by using , but since this is outside the main gist of the present invention, the explanation will be omitted to avoid complication. Or, JP-A-50-134
The above-mentioned problem of optical axis displacement can also be solved using the invention disclosed in Japanese Patent No. 440.

That is, when the copy magnification is converted as described above, the first and second
Since the travel time of the mirror in the forward travel period also changes, in order to always align the leading edge of the copy document image with a fixed position on the photoreceptor, the forward travel start points of the first and second mirrors are shifted slightly in accordance with the copy magnification when scanning the document. The starting time and the time when the above-mentioned fixed position of the photoreceptor reaches the exposure area are made at the same time. The time points at which the forward travel of the first and second mirrors start may be determined in accordance with each copying magnification by adding a shift time corresponding to the displacement of the optical axis to this shift time. This can also be easily accomplished by using a timer and/or microswitches as described above, but the explanation will be omitted to avoid complexity. In this case, although the transfer paper feeding timing is not changed according to the copying magnification, the leading edge of the transfer paper and the leading edge of the copied original image coincide. Incidentally, the second reflecting means supported by the second support body is a reflecting means as described in Japanese Utility Model Publication No. 52-41860, that is, a mirror facing the first mirror, and a mirror facing this mirror and the lens. By using a reflecting means consisting of two mirrors, each tilted at an angle of 45 degrees with respect to the optical axis, the above-mentioned problem of optical axis displacement when converting the copying magnification does not occur, and therefore There is no need to change the paper feeding timing or the start point of forward movement of the reflecting means according to the copying magnification as described above.

FIG. 7 shows an example of a control circuit suitable for an apparatus using the above-mentioned orthogonal two mirrors as the second reflecting means or an apparatus for controlling the sheet feeding timing with respect to the copying magnification as described above.
S is a DC power supply, CB is a copy button, M is a motor, R is a variable resistor for adjusting the input to the motor M in order to rotate the motor M at a rotation speed that is contrary to the copy magnification, and CLF is a motor M. CLB is a clutch that transmits the rotational force of the motor M to the pulley shaft 261 in the reverse direction.

CS is set to 0N by a counter (not shown). 0FF control is performed. This counter has copy button C
It is activated when B is pressed, and a set of operations of the first mirror 15 reaching the turning position and returning from the turning position to the home position is counted as one operation. Therefore, the number of times this counter counts is equal to the number of copies.
The switch CS closes when the copy button is pressed, and opens the contact when the counter counts the preset desired number of copies. Now, it is assumed that the first and second supports 23 and 24 are in their respective home positions indicated by solid lines in the figure, and a full-size copy is to be made.

At this time, microswitches MS1, MS2, and MS4 are all closed. When the desired number of copies is set on the counter and the copy button CB is pressed, relay RC is activated and switches RCl and RC2 are closed. Switch RCl
, the operation of relay RC is maintained until switch CS is opened. Now, since micro switch MS2 is closed, relay R2 is activated and switches R2l, R2
Close 2. On the other hand, since the microswitches MS1 and MS4 are also closed, the relays R1 and R4 are also activated, closing the switches R11 and R41, respectively. Switch Rll, R4l
By closing, the operation of the corresponding relays R1 and R4 is maintained until the switches R21 and R22 are opened, respectively.
The relay R4 controls a switch (not shown) between the lamp 18 and the power source, and when activated, this switch is closed and the lamp 18 is turned on. On the other hand, relay R1 also controls switch Rl2, and the above operation causes switch Rl2 to
Connect to contact F side. This allows the forward rotation clutch CL to
F is activated. Since the motor M is rotating due to the closing of the switch RC2, due to the operation of the clutch CLF,
The first and second supports 23 and 24, and therefore the first and second mirrors 15 and 16, start traveling from their respective home positions toward their respective turning positions at a speed ratio of 1:%.
At this time, the original is illuminated by a lamp 18, scanned by first and second mirrors 15 and 16 moving forward, and slit exposed onto the photoreceptor 1. first and second mirrors 15,
16 finishes scanning the document from one end to the other and reaches each folding position, the first support 23 comes into contact with the micro switch MS2 to open its contact. Then, relay R2 stops operating and switches R2l and R22 open.
When the switch R22 is opened, the operation of the relay R4 is stopped, so that the switch R4l is opened and the lamp switch is also opened, so that the lamp 18 is turned off. On the other hand, switch R2
When 1 is opened, the operation of relay R1 is stopped, switch R11 is opened, and switch R12 is switched to the B side contact. Therefore, the reversing clutch CLB is activated, and the first and second mirrors 15, 16 begin to move back toward their respective home positions. Incidentally, when the first support body 23 starts to move back and leaves the micro switch MS2, this switch MS2 is closed and the relay R2 is activated, and the switch R is closed.
2l, R22 is closed. First and second mirrors 15, 16
However, when the first and second supports 23 and 24 return to their respective home positions, the first support 23 closes the micro switch MSl, so that the first and second mirrors 15 and 16 are turned off again. The forward and backward movements are repeated. In this way, when the first and second mirrors 15 and 16 return to their home positions by reciprocating the number of copies set in the counter, the switch CS is opened. This allows relay R
The operation of motor C is stopped, switch RCl is opened, and switch RC2 is also opened, and rotation of motor M is stopped. That is, the first and second mirrors 15 and 16 stop moving. Next, when switching from full size copying to reduced copying, that is, pulley 2
8, 29 from the solid line position in Fig. 5 to the broken line position 28', 2
9', the support 23 of the first mirror is displaced from the solid line position to the broken line position 23''.

At this time, the second mirror support 24 is stationary. The above displacement of the first support 23 causes the microswitch MS3 to open its contacts. In this state, when the number of copies is set on the counter and the copy button CB is pressed, the relay RC is activated and the switch RC2 is closed, so that the motor M starts rotating.
Since micro switch MS2 is closed, relay R2
operates to close switches R2l and R22, but since microswitches MSl and MS4 are open, relays Rl and R4 do not operate. Therefore, the lamp 18 is in an off state, and the switch Rl2 is connected to the contact B side. Therefore, the reversing clutch CLB is operated, and the first and second mirrors 15 and 16 are moved until the support 23 of the first mirror comes into contact with the macroscopic switch MS4, that is, the first and second mirrors are in the home position. Go backwards until you reach . When the first and second mirrors reach the home position, the micro switch M
Sl is closed, and the first and second mirrors 15 and 16 move forward. At this time, the micro switch MS4 is closed and the lamp 18 is turned on. The rest is the same as above.
, the second mirrors 15 and 16 repeat reciprocating motions, scan the document a number of times corresponding to the set number of copies, and return to the home position, when the switch CS is opened and the rotation of the motor M is stopped. Incidentally, during reduction copying, the variable resistor VR is adjusted to adjust the input to the motor M, so that the pulley 26 is rotated at a peripheral speed that is substantially the reciprocal of the copying magnification multiplied by the peripheral speed of the photoreceptor 1. This is as stated above. Next, after the reduced copying is completed, pulleys 28 and 29 are used to convert to the same size copying.
Returns from the dashed line position to the solid line position.

Then, the second mirror support body remains stationary at the dashed line position 24' in FIG. 5, and the first mirror support body 23 moves from the solid line home position to the dashed line position 23I. This closes the microswitch MS3. Therefore, when the desired number of copies is set on the counter and the copy button CB is pressed, the relay RC is activated as described above and the switch RC is activated.
2 closes and motor M starts rotating, and relay R
3 is activated to close switch R3l. Switch R3
Closing of R1 activates relay R1 even though microswitch MS1 is open. When the relay R1 is activated, the switch R1l is activated and the switch R12 is connected to the F side contact. Therefore, the forward rotation clutch CLF is activated and the first and second mirrors 15 and 16 begin to move forward toward the home position. When the first mirror 16 reaches the predetermined home position and the second mirror 16 reaches the home position for full-size copying, the first support 23 closes the micro switch MS4. The lamp 18 lights up. On the other hand, the micro switch MSl is also closed, but since the relay R1 has already continued to operate due to the closing of the switch R1l, the first and second mirrors 15 and 16 continue to move forward toward the turning position, and the original is scan. Note that when the first support 23 comes into contact with the micro switch MS1, the micro switch MS3 is already open, so the switch R31 is already open. After that, the same operation as in the same-size copying described above is repeated, and when the first and second mirrors 15 and 16 reciprocate for the set number of copies and return to the home position, the switch CS opens and the first and second mirrors are copied.
Mirrors 15 and 16 stop. It goes without saying that when converting from a reduced copy to a full size copy, the variable resistor VR is adjusted to adjust the rotational speed of the motor M as described above.
In the embodiment described above, the first mirror support 23 is fixed to the mirror forward driving wire 32 at a position between the fixed pulley 27 and the movable pulley 25 provided on the second mirror support 24. However, as shown in FIG. 8, it may be fixed at a position a between the second pulley 29 for copying magnification conversion operation and the movable pulley 25. In FIG. 8, compared to the example in FIG. 2, the positions of the drive pulley 26 and the member 31 that substantially fixes the wire end to the apparatus body are reversed. That is, regarding the positions of the first and second pulleys 28 and 29 that are integrally displaceable for the magnification conversion operation,
The driving pulley 26 is arranged on the movable pulley 25 side provided on the second mirror support, and the wire end fixing member 31 is arranged on the fixed pulley 27 side. One end of the wire 32 is fixed to a pulley 26, and this wire 32 is suspended from the pulley 26 to a second pulley 29 for magnification conversion operation, a dynamic pulley 25, a constant pulley 27, and a first pulley 28 for magnification conversion in order. ing. Needless to say, the first and second pulleys 28 and 29 for magnification conversion correction are further fixed pulleys 2 than the end point of forward movement of the fixed point a of the wire 32 to the first mirror support, that is, the turning point.
7 and the member 31. In FIG. 9, 37 is a fixed pulley rotatably supported by a shaft 371 provided at a fixed position within the device.

This pulley 37 is the first pulley for magnification conversion operation that is integrally displaced.
, are arranged on the opposite side from the pulley 27 with respect to the positions of the second pulleys 28 and 29. The first mirror support is then fixed to the wire 32 at point b between the pulleys 37 and 27. One end of the wire 32 is fixed in place by the member 31, and the wire 32 is connected to a movable pulley 25 provided on the second mirror support.
, the first pulley 28 for magnification conversion operation, the constant pulley 37, the constant pulley 27, and the second pulley 29 for magnification conversion operation, and the other end is fixed to the drive pulley 26. It goes without saying that the pulleys 28 and 29 are arranged closer to the pulley 27 and the pulley 26 than the end point of the forward movement of the movable pulley 25, that is, the turning point. In the embodiments shown in FIGS. 8 and 9, as in the embodiment shown in FIG. 2, between adjacent pulleys for wire tensioning, and between the part where the wire end is fixed to a fixed position in the device and the pulley next to it. The wire 32 is connected to the first
It extends substantially parallel to the guide rail of the second mirror support. And also pulleys 26, 27, and 37
each rotates in a fixed position within the device. Further, wires 32 are wound around the first pulleys 28 and 29 for magnification conversion operation from substantially opposite directions. The fact that the pulleys 28 and 29 are overflowing and displaced in the direction in which the wire 32 is stretched to the husband and wife by the copying magnification conversion operation is the same in the example shown in FIGS. 8 and 9 and the example shown in FIG. When converting the copy magnification from normal to reduced, pulleys 28 and 29 are moved from the solid line position to the dashed line position 281 and 29' in the figure without rotating the pulley 26 in FIGS. 8 and 9. . At this time, points a and b move to positions a' and b', respectively.The amount of displacement is % of the amount of displacement of the first mirror, and upon displacement, the first and second pulleys 28 and 29 rotate in the same direction. This is also the same as the example in FIG. When scanning a document, the first and second
To move the mirror forward from its home position, the drive pulley 26 is rotated in the direction of arrow All in FIGS. 8 and 9 at a speed corresponding to the set copying magnification. Then, the fixed point of the first mirror support to the wire 32 travels in the direction of arrow Al2, and the movable pulley 25 travels in the direction of arrow Al3, which is the same direction as arrow Al2, at a speed of % of the fixed point. For the forward movement of the first and second mirrors, the mechanism explained in FIG.
, means for reversing the driving pulleys 26, 33, etc. can be used. In the device shown in FIG. 8, when the first mirror 15 and the second mirror 16 move forward, the pulleys 26, 29,
25 rotates. Pulleys 28, 29, 2 during magnification operation
5 and 27 rotate. In the example shown in FIG. 9, all pulleys rotate when the first and second mirrors 15 and 16 move forward and backward. When changing the magnification, pulleys 28, 29, 27, 3
7 rotates. In both the examples shown in FIGS. 8 and 9, the pulleys 28 and 29 will not be displaced unless a magnification change operation is performed. Further, as is clear from the above description, in the example of FIG. 9, the first and second pulleys 28 and 29 for magnification conversion operation rotate at the same time and in the same direction. Therefore, in the example shown in FIG. 9, as long as the pulleys 28 and 29 have the same diameter, it is not necessary to make them rotatable independently of each other, and they can be fixed relatively immovably with bolts or the like. However, if the diameters are different, the pulleys 28 and 29 can be rotated independently of each other. In other embodiments, the pulleys 28 and 29 may have different diameters. The embodiment shown in FIG. 10 is a partial modification of the example shown in FIG.

As mentioned above, the movable pulley 25 is rotatably supported on the second mirror support 24, and the first mirror support 23 is fixed to the wire 32 at point C between the pulleys 25 and 27. In the embodiment shown in FIG. 10, the diameter of the first pulley 28 for zooming operation is smaller than the diameter of the second pulley 29. The diameter may be reversed. In the embodiment of FIG. 10, the pulleys 28, 2
9 are rotatably supported on separate shafts 306 and 307. However, the two shafts 306, 307 are one support means 3
It is integrally supported by 08. When converting from a full size copy to a reduced copy, the support means 308 is displaced leftward from the solid line position in the figure by % of the displacement amount of the first mirror 15, and the pulleys 28 and 29 are moved to the positions 28'' and 29 indicated by the broken line, respectively. In other words, although the pulleys 28 and 29 are not provided coaxially in this example, both pulleys 28 and 29 are simultaneously displaced in the same direction and by the same distance by the variable magnification operation. In other words, as in other embodiments, the pulleys 28 and 29 are integrally displaced.If the pulleys 28 and 29 are moved to the dashed line positions 28'' and 29'', the point C moves to the position C. In the embodiment, the wire 32 is stretched parallel to the first and second mirror guide rails 22 between adjacent pulleys.

Although this is preferable in terms of downsizing the mechanism, it is also possible to do it as shown in FIG. 11. FIG. 11 shows a partially modified version of the embodiment shown in FIG. Reference numerals 38 and 39 denote fixed pulleys rotatably supported by shafts 381 and 391 respectively installed at fixed positions within the device.

The wire 32 is suspended around a pulley 38 between pulleys 25 and 28 to change its direction, and is suspended around a pulley 39 between pulleys 27 and 29 to change its direction. It goes without saying that the pulley 38 is positioned closer to the pulley 27 than the forward movement end point of the pulley 25. The embodiment shown in FIG. 2 and the embodiment shown in FIG.
The illustrated embodiments are the same. In short, in any embodiment, the first
The wire 32 for driving the second mirror forward is stretched substantially parallel to the guide rail 22 at least within the movement range of the connecting point of the first mirror support 23 at the portion where the connecting point is located. In addition, the part that the movable pulley 25 comes into contact with is the movable pulley 2
The portions stretched on both sides of the movable pulley 25 are stretched substantially parallel to the guide rail 22, at least within the movement range of the movable pulley 25. Furthermore, a wire 32 is hung around the first and second pulleys 28 and 29, which are integrally changed by the magnification changing operation, as follows. That is, the wire 32 is wound around the first pulley 28 from a direction substantially opposite to that of the second pulley 29. and the pulley 28 of the wire 32
The parts stretched on both sides of the pulley 28
are parallel within the displacement range of the wire 32, and the pulley 2 of the wire 32
The parts stretched on both sides of pulley 9 are parallel at least within the displacement range of this pulley 29. That is, the wire portions stretched on both sides of the pulleys 28 and 29 are all parallel to each other. It is desirable to stretch the wire 32 in this manner. In addition, in the embodiments shown in FIGS. 8 and 11, pulley 2
As the displacement mechanisms 8 and 29, those explained in FIG. 4 can be used, and the means shown in FIGS. 5 and 7 can be used to control the traveling of the first and second mirrors.

Furthermore, in the above embodiments, both the first and second reflecting means are each made up of one mirror, but one or both of them can be made up of a plurality of mirrors. For example, two orthogonal mirrors as disclosed in Japanese Utility Model Publication No. 52-41860 can be used as the second reflecting means. Furthermore, when a member or means is referred to herein as being fixed in a fixed position or rotating in a fixed position, reference is made herein to a member or means that is substantially immovable or a member or means of a reproduction apparatus. A means that is fixed at a fixed position, such as a beam, girder, or side wall, or rotated there without being substantially displaced anywhere.

Further, the term "substantially fixed to the main body of the apparatus" refers to the fact that the apparatus is fixed to an immovable member in the copying apparatus as described above in a state where the position does not substantially change. Further, in the embodiment, there are two copy magnifications that can be selected, ie, the same magnification and one reduction magnification, but it is also possible to select three or more copy magnifications. In that case, pulley 28
, 29 may be displaced to three or more positions. Furthermore, in the above embodiments, the speed of the photoreceptor is made the same for any copying magnification, but each time the copying magnification is changed, the circumferential speed of the photoreceptor is changed correspondingly.
It is also possible to keep the forward movement speed of the reflecting means constant regardless of the copying magnification. In this case, if the circumferential speed of the photoreceptor during full-size copying is v, and therefore the forward movement speeds of the first reflecting means and the second reflecting means are v and v/2, respectively, then when the copying magnification is m, the photoreceptor is moved to Mv. Move at a circumferential speed of . Furthermore, in the above embodiments, the lens is displaced together with the first reflecting means by the magnification conversion operation, but the lens may be fixed at a predetermined position within the apparatus for any copying magnification.

In this case, referring to FIG. 1, the third and fourth mirrors may be displaced by the magnification changing operation so as to satisfy the above-mentioned formula. The amount of displacement of the first mirror to satisfy the above-mentioned formula is larger than that in the above embodiments. Note that the wire-like member includes a so-called normal wire formed by knitting a plurality of fibrous materials, a single fiber-like member, a chain, a flat belt-like member,
A belt-like material with perforation can be used, and a chain or belt with perforation can be used as a pulley or pulley, so-called sprocket, and a belt-like material can be called drum. Can be used.

[Brief explanation of drawings]

FIG. 1 shows an electrophotographic copying apparatus to which the present invention can be applied, FIG. 2 shows a main part of an embodiment of the present invention, FIG. 3 shows an example of a pulley for optical path length conversion, and FIG. 4 shows an example of a variable magnification drive means. , FIGS. 5 and 7 illustrate an example of the control means of one embodiment of the present invention, FIG. 6 illustrates the optical axis displacement, and FIGS. 8 to 11 each illustrate still other embodiments of the present invention. This is a diagram for 2 is a photosensitive drum, 13 is an original platen, 15 is a first mirror 1
6 is a second mirror, 17 is a lens, 22 is a guide rail,
23 is a first support body, 24 is a second support body, 25 is a movable pulley,
26 is a first drive pulley, 27 is a fixed pulley, 28 and 29 are displacement pulleys for variable magnification, 32 is a first wire, 33 is a second drive pulley, 34 is a fixed pulley, 35 is a second wire, MSl, 2
, 3 are micro switches, M is a motor, and CLF and B are clutches.

Claims (1)

[Scope of Claims] 1. A document table on which a document is placed with the leading end of the scanning start side aligned in the same position at any copying magnification, a first support supporting a first reflecting means, and a second reflecting means. a supported second support, a movable pulley means provided on the second support, a drive pulley means, and an end wire means having an end fixed to the main body, the first and second a weir means wound around the moving pulley means and the driving pulley means and fixed to the first support body in order to scan the original by moving the reflection means at a speed ratio of 1:1/2; Wire direction changing means for hanging a wire and changing its direction, the wire direction changing means being displaceably provided at a position independent of the first and second supports, the wire means relating to a fixing part to the first support. Wire direction changing means hung from opposite directions on one side and the other side, respectively, and changing the position of this wire direction changing means to a position corresponding to the selected magnification by a magnification changing operation. an optical path length changing means for displacing the first reflecting means to change the optical path length; and after the first reflecting means is displaced by the optical path length changing means and before starting scanning the original, the first reflecting means is configured to scan the original. A copying apparatus having variable copying magnification, comprising a return means for returning to a home position forward of a starting position. 2. The wire direction changing means has a first pulley on which a portion of the wire means is hooked on one side with respect to the fixing portion to the first support and a second pulley on which the other side is hooked. A copying apparatus according to claim 1. 3. The copying apparatus according to claim 2, wherein the first and second pulleys are supported by the same support means and are moved integrally. 4. The wire means is hung on the first pulley between a part fixed to the first support means and a part fixed to the device body, and has a part fixed to the first support means and a part engaged with the drive pulley means. 4. The copying apparatus according to claim 3, wherein the copying apparatus is hung on the second pulley between the first and second pulleys.