JPS60165633A - Forming device for original image of variable magnification - Google Patents

Abstract

PURPOSE:To position a gear accurately even when a spring clutch is used by positioning the gear which is selected during variation in copy magnification by the spring clutch and a means which controls the clutch position. CONSTITUTION:The clutch 41 is provided to a shaft 31 and claws raised 441- 444 are formed on a control ring 42 corresponding to copy magnifications; and gear groups 3-6 corresponding to the magnifications m1-m4 are provided to support plates 11 and 12 concentrically with the shaft 31 and a control stopper 60 is fitted to a lever 80. When a desired magnification is set, the shaft 31 and support plates 11 and 12 rotate to engage the stopper 60 with one of the raised claws 441-444 and also select and engage the gear group corresponding to the specific magnifiction with an output side gear 2, thereby locking the support plates 11 and 12 with a pin 71. Consequently, the selected gear is positioned accurately even when the positioning precision of the spring clutch is low.

Description

[Detailed description of the invention] The present invention relates to a variable magnification original iron forming apparatus.

In a variable magnification original image forming device, in order to change the magnification of projecting an original image onto a photoconductor, the position of optical members such as lenses and mirrors that make up the projection optical system is changed, or in an original scanning type In order to change the speed of the document scanning means in accordance with the selected magnification, it is necessary to change the gear position of the transmission means. In order to change the document image forming magnification, a spring clutch is used to continue the transmission of the driving force from the drive source to the various members that are moved to positions corresponding to the magnification. Using this method simplifies the mechanism and reduces manufacturing costs, making it useful in practice. However, when the driving force for moving the movable body to a position corresponding to the selected magnification is transmitted via a spring clutch, if the movable body is positioned to stop based only on the disengagement of the spring clutch, the stop position will vary.

This is because, due to variations in the precision of the individual springs used, the point at which the locking member is engaged and disengaged from the control ring and the point at which the driving force is actually disconnected or connected may vary slightly between individual clutches. It is from. Therefore, if such variations occur,
If the moving object is the above-mentioned optical member, the original image on the photoreceptor may be blurred or the magnification may be out of order.If the moving object is a variable speed gear of a transmission for the original scanning means, the original scanning means may not move smoothly. First, inconveniences such as blurring of the image occur.An object of the present invention is to solve the above-mentioned inconveniences. The present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are explanatory diagrams of examples of electrophotographic copying apparatuses to which the present invention can be applied. In both figures, 101 is a drum-shaped electrophotographic photosensitive member that rotates in the direction of the arrow, but the electrophotographic photosensitive member 101 is not limited to this, and may be an endless belt-like member having a linear movement section. Photoreceptor 101 is first uniformly charged by charger 102, and then exposed to a light image of original 100 scanned by an original scanning device. This light beam is projected by a zoom lens 103 onto the photoreceptor 101 at a selected magnification. The zoom lens 103 is then displaced to a position corresponding to the magnification selected by the magnification changing operation by a known means or by means described later, and is moved to a position corresponding to the selected magnification in conjunction with the movement at this time. The focal length is changed to In the figure, P and ~P are the positions of the zoom lens 103 when the original image forming magnification is m and ~, respectively. A light beam from the document exiting the lens 103 is reflected by the fixed mirror 104 and directed toward the photoreceptor 101 . Note that when a fixed focus lens is used as the lens 103, the magnification changing operation displaces the lens to a position corresponding to the selected magnification, and also displaces the mirror 104 and the like, thereby changing the total optical path length between the original and the photoreceptor. It changes according to the selected magnification.

The latent image formed on the photoreceptor 101 by the above-mentioned photoimage exposure is developed by a developing device 105 using toner. The toner image obtained by this development is transferred by a transfer device 106 onto a transfer material 107 that is conveyed in the direction of the arrow. After the transfer, the toner image is transferred to the transfer material 107 by a fixing device (not shown).
Meanwhile, the photoreceptor 101 after the transfer is cleaned by a cleaning device 108.

Now, in FIG. 1, 109 is a document illumination lamp fixed at a fixed position. The document 100 is placed on a document table 110, and in order to scan the document, the document table 110 moves in the direction of the arrow through a position illuminated by a lamp 109 under the guidance of a known guide means. Original table 11 in the arrow direction
0, the light from the document illuminated by the lamp 109 is reflected by the mirror 111 fixed at a fixed position, passes through the zoom lens 103 and mirror 104, and is exposed to the photoreceptor as described above. As described above, a latent image of the original is formed. When the scanning of the original is completed, the original table 110 moves back in the direction of arrow B and returns to the starting position of movement in the direction of arrow A.

A rack 111 is fixed to the document table 110. A binion 112, which will be described later, is engaged with this rack 111, and by rotationally driving this binion 112 in the direction of arrow C (normal rotation direction), the document table 110 is moved in the direction of arrow A, and in the direction of arrow (#). The document table 110 is moved in the direction of arrow B by being rotationally driven in the reverse direction). The moving speed (original scanning speed) of the document table 110 in the direction of arrow A is changed in accordance with the selected document image forming magnification. That is, the table 110 is moved in the direction indicated by the arrow at a speed that is the moving speed of the peripheral surface of the photoreceptor 101 divided by the selected image forming magnification. As a result, the magnification of the original image formed on the photoreceptor in the direction of movement of the photoreceptor is set to the selected magnification. Therefore, the pinion 112 is rotationally driven in the direction of arrow C at a speed corresponding to the selected magnification,
The table 111 is moved in the direction of arrow A at the above speed. 1 unit
The moving speed of 11 in the direction of arrow B may be the same speed for any magnification, or may be changed depending on the selected magnification. Therefore, the speed at which the pinion 112 is rotated in the direction indicated by the arrow may be the same for any magnification, or may be changed in accordance with the selected magnification. Note that, instead of the rack and pinion mechanism described above, a wire, a pulley mechanism, etc. may be used to transmit the driving force to the document table.

In the apparatus shown in FIG. 2, the document table 110' is fixed at a fixed position, and the document is scanned by moving the mirror and mirror.

That is, 113 is a mirror fixed to a first movable mirror 116, and 114 and 115 are mirrors fixed to a second movable mirror 117. The tables 116, 117 are guided parallel to the document table 110' by known guiding means. In addition, unit 1
A document illumination lamp 109' is also fixed to 16 and moves integrally with the mirror 113.

The mirror 113 and the mirrors 114 and 115 are moved at a speed ratio of 2:1 in order to maintain a constant optical path length between the original and the lens, and the most commonly used driving mechanism uses the principle of a movable pulley. It was there. That is, 118 is a pulley (moving pulley) rotatably attached to the second mirror unit 117. 119 is a wire for transmitting driving force, one end of which is 1.
After locking 19' to the main body of the device, wrap it around the above-mentioned pulley 118, fold it back, hang it around the pulley 120 set at a fixed position, fold it back again, and wrap it around a drive pulley 121 (described later) one or more times, then set it. After hanging it on the pulley 122 provided at the position and folding it back again, and hanging it on the pulley 118 and folding it back,
The other end 119'' is locked to the main body of the apparatus. The first mirror unit 116 is fixed to a wire 119 between pulleys 118 and 120.
1 is rotated in the direction of arrow C (normal rotation direction), mirror 113. Lamp 109' and mirrors 114, 115 are 2:
It moves in the direction of arrow A at a speed ratio of 1. At this time lamp 10
The light beam from the original illuminated by 9' is reflected by mirror 113.11.
The photoreceptor 101 is exposed to light as described above through the zoom lens 103 and the mirror 104, forming an electrostatic latent image of the document. When scanning of the original is completed, the drive pulley 121 is driven to rotate in the direction of the arrow (reverse direction), and the mirror 113, lamp 109' and mirrors 114, 1
15 moves back in the direction of arrow B at a speed ratio of 2:1 and returns to the starting point of movement in the direction of each arrow. The moving speed (original scanning speed) of the mirror 113 in the direction of arrow A is changed in accordance with the selected original image forming magnification as described above.

That is, the mirror 113 and the lamp 109' are therefore
6 is moved in the direction of arrow A at a speed obtained by dividing the moving speed of the circumferential surface of the photoreceptor 101 by the selected image forming magnification.

So drive boo! 7121 is rotationally driven in the direction of arrow C at a speed corresponding to the selected magnification, and moves the table 116, therefore the mirror 113, and the lamp 109' in the direction of arrow A at the above speed.
move in the direction. of the pedestal 116 and therefore the mirror 113;
The speed of movement of the lamp 109' in the direction of arrow B may be the same speed for all magnifications, or may be changed depending on the selected magnification. Therefore, the rotation speed of the drive pulley 121 in the direction indicated by the arrow may be the same for any magnification, or may be changed in accordance with the selected magnification. Note that even if the speed of the mirror 113 is changed, the mirror 11
4,115 moves at 1/2 the speed of mirror 113.

In the above, the document was scanned by moving the document table in FIG. 1 and the mirror in FIG. The present invention can also be applied to a device using a so-called document feeding device that scans a document by conveying the document through a position. Therefore, in this specification, the document scanning means is a general term for the movable document table, the movable optical members such as the movable mirror, the document conveying roller or the belt, and other components that move for document scanning.

Next, the drive mechanism for the binion 112 and pulley 121 will be explained.

FIG. 3 is a partial explanatory diagram of an embodiment to which the present invention is applied, and in order to avoid complexity, each gear is shown with its own pitch circle. FIG. 4 is an explanatory diagram of a part of the apparatus seen in the direction AA in FIG. 3.

In each figure, 1 is the input gear located at a fixed position, 2
is an output side gear arranged at a fixed position, and 3°4, 5.6 is a gear group for transmitting driving force. Each gear group 3.4
．． 5.6 are first gears 31, 41°5', 6' respectively
and second gears 3', 4'', 5'', and 6'. The gear ratio of the first gear and second gear of each group, that is, the ratio of the number of teeth of the first gear to the number of teeth of the second gear, differs for each group. In this embodiment, the gear ratio between the first gear and the second gear of gear group 3 is 1, but there is no need to limit it to this.

In addition, in the embodiments shown in FIGS. 3 and 4, the first
The gear and the second gear are fixed to each other, so that when the first gear rotates, the second gear also rotates integrally with it.

The first gear and the second gear of each gear group are connected to the support plate 1, respectively.
It is rotatably supported on shafts 7, 8, and 9 degrees 10 supported by 1.12. The shafts 7, 8° and 9.10 are common shafts for the supported first gear and second gear, respectively, but on the other hand, the support plates 11 and 12 are arranged so that the spacing for housing each gear is the same. It also serves as a connecting member for integrally fixed connection.

Here, the supporting plates 11 and 12 are rotatable in the direction of arrow R in FIG. 3 (or in the opposite direction) by a mechanism to be described later.
The gear groups 3, 4, 5, 6 are supported on support plates 11, 12 at intervals in the rotational direction. The above interval can be set arbitrarily within a range where each gear group does not interfere with each other, but in the illustrated example, the axis 7 of each gear group
, 8゜9.10 are placed on the support plate 1 at 90 degree intervals in order.
It is fixed at 1.12.

In FIG. 3, the first gear 3' of each gear group.

The pitch circles 4', 5', and 6' circumscribe one common virtual circle C8. In the illustrated example, this circle C8 is the pitch circle of the input gear 1. On the other hand, the second
The pitch circles of gears 3'', 4', 5', and 6' are different from 1.
This circle C2 is inscribed in the two common virtual circles, and the pitch circle of the output gear 2 is circumscribed in this circle C2.

The imaginary circles c, lc are concentric circles, and the support plates 11, 12 rotate around an axis located at the center of the imaginary circles C, , C2. In this way, the first gears 3', 4', 5', and 6' of each gear group always mesh with the input side gear 1 and provide the input gear no matter what rotational position the support plates 11, 12 are stopped at. , and support plate 1
1.12 revolves around the axis of the support plate 11.12 while being engaged with the input gear 1 during rotation. The second gears 3', 4', 5', and 6' of each gear group mesh with the output gear 2 when the gear group to which it belongs comes to the operating position. In Fig. 3, gear group 4 is in the operating position, but in any case, the gear group that has reached the operating position receives the driving force from the input gear 1 through the first gear and the second gear in order. , and is transmitted to the output gear at a speed corresponding to the gear ratio of the second gear. The axes of the gear groups that have reached the operating position are aligned on a straight line connecting the input gear axis and the output gear axis.

As shown in FIG. 4, in this embodiment, when changing the output speed, the support plates 11 and 12 are rotated by the drive force from the drive motor 20, thereby saving on the number of drive sources. There is. In this embodiment, the output shaft 23 is selectively
It also has a mechanism that rotates it in the direction.

In FIG. 4, the rotational driving force of a motor 20 rotating in one direction is rotatably supported by a shaft 15 via a toothed belt 19. The input gear 1 is supported by a frame 15 via a bearing 29, and is fixedly connected to a gear 30 by a connecting pipe 28 passing through a hole 12' of the support plate 12. The gears 1 and 30 are integrally connected to the device frames 14 and 34.
A shaft 31 rotatably supported via bearings 32 and 33 in
is rotatably supported. The gear 30 meshes with the gear 35. The gear 35 is connected to a gear 38 fixed to the shaft 13 via a loose spring clutch 36 having a ratchet wheel 37 . That is, when the control pawl 58 (FIG. 5) engages with the ratchet wheel 37 and the spring clutch 36 operates, the gear 3
5 rotates integrally with the gear 38, and when the control pawl 58 separates from the ratchet wheel 37 and the spring clutch 36 becomes inactive, the connection between the gears 38 and 35 is severed, even if the gear 38 is rotating. Gear 35 does not rotate. Therefore, when the motor 20 is operating and the shaft 13 is rotating, when the spring clutch 37 is operating, the rotation of the shaft 13 is caused by the gear 35°30.
1, and then a gear group (4th
In the case of the figure, the signal is transmitted to the gear 2 via the group 4), and the output shaft 23 is supported to rotate in the positive direction at a speed corresponding to the selected magnification. Alternatively, the drive pulley 121 is fixed.

Therefore, if the shaft 23 rotates in the normal rotation direction, the above-mentioned pinion 1
12 or the drive pulley 121 rotates in the direction of arrow C (normal rotation direction) shown in FIGS. 1 and 2. The document scanning means thus moves in the direction of arrow A at a speed corresponding to the selected imaging magnification. Note that the pinion 112 or the drive pulley 121 is not directly connected to the shaft 23, but may be connected via a gear train or chain sprocket mechanism.

On the other hand, even if the motor 20 is operating and the shaft 13 is rotating, if the spring clutch 36 is not operating, the gear 35 will not rotate, so the shaft 23 will not rotate in the normal rotation direction. Therefore, the document scanning means does not move in the input direction, and the document is not scanned.

A speed switching gear 40 is rotatably fitted on the shaft 31 with play. This gear 40 is connected to the shaft 31 by a spring clutch 41, and has a vertical pawl 43I provided on a control ring 42.

43,. 43s, 434, 44. ．． 44. ．． 44. ．． 4
4. When the control pawls 59 (FIG. 5) and 160 (FIG. 8) are not engaged with either of them, the spring clutch 41 operates to fixedly connect the gear 40 to the shaft 31, and the gears 38, 46, 47 The driving force from the motor 20 transmitted through the shaft 31 is transmitted to the shaft 31 to fully rotate the support plates 11, 12 supporting the gear groups 3, 4, 5, 6. On the other hand, if the control pawls 59 and/or 60 are engaged with any of the above-mentioned vertical pawls, the spring clutch 41 is deactivated, and the gear 40 idles around the shaft 31, so that no rotational force is applied to the shaft 31. Not communicated. Incidentally, 45 is a spring type spring having one end locked to the control ring 42 and the other end locked to the shaft 31. (By the rotation of the shaft 31, the support plate 11,
(The mechanism for rotating the frame 15 will be described later.) As shown in FIG.
This gear 46 meshes with a gear 47 rotatably supported by a shaft 49 fixed to the frame 15.34.

Since the gear 47 meshes with the gear 40, the gear 40 always rotates in the direction of the arrow R when the shaft 13 rotates.

On the other hand, the gear 47 meshes with a gear 50 fixed to a shaft 51 rotatably supported by the frame 15.34 via bearings 52.53.

Therefore, the gear 50 also constantly rotates while the shaft 13 is rotating. This gear 50 has a slack type spring clutch 54 having a type wheel 55.
A gear 53 is connected via. That is, when the control pawl 61 (FIG. 5) engages with the mold wheel 55, the barb clutch 54 operates, causing the gear 53 to rotate integrally with the gear 50, and when the control pawl 61 separates from the mold wheel 55, the barb clutch 54 operates. 54 is inactive, and even if gear 50 is rotating, gear 53 does not rotate, or can rotate in the opposite direction to gear 50. A gear 56 fixed to the output shaft 23 meshes with the gear 53. Therefore, when the spring clutch 36 is inactive and the spring clutch 54 is activated, the rotational driving force from the shaft 13 is transmitted to the shaft 23 through the gears 38, 46, 47, 50, 53, 56, and the shaft 23 is rotated in the reverse direction. Rotate to .

On the other hand, the spring clutch 54 is inoperative, and the spring clutch 36
When actuated, the shaft 23 rotates in the above-mentioned straight direction at the selected speed. Therefore, the binion 112 or the drive pulley rotates in the direction of the arrow. By alternately switching the spring clutches 36 and 54 between the activated and non-activated states in this way, the document scanning means can be moved in two directions: in the direction of arrow Ajj and in the opposite direction of arrow B. . However, in this embodiment, the speed of movement in the direction B is one and cannot be changed;
．． If a speed change mechanism having a plurality of gear groups is provided on the rotatable support plate 56 as described above, it is possible to change the speed in the reverse direction of the shaft 23 and therefore also the speed of movement in the B direction of the document scanning means.

Now, in FIGS. 6, 7, and 8, the support plate 11.1
The rotational drive and its positioning will be explained. This support plate 11.12 is mounted on the shaft 31 so that it can rotate relative to this shaft. 62 is a drive plate fixed to the shaft 31 and rotates in one direction (arrow R). A bottle 63 is formed on this drive plate 62 . This bottle 6
3 passes through an elongated hole 64 provided in the support plate 11 and long in the rotation direction of the support plate 110.

On the other hand, a bottle 65 is firmly planted on the support plate 11. A spring 66 is hung between the bottles 63 and 65. Therefore, if the spring clutch 41 operates and the shaft 31 rotates, the drive plate 62 will move even when the support plate 11 has stopped rotating.
The support plate 1 is stretched while accumulating elastic force by stretching the spring 66 within the range regulated by the longitudinal end of the elongated hole 64.
It is rotatable relative to 1.

The support plate 11 is provided with grooves 67, 68 and 69 degrees 70 corresponding to the gear groups 3 and 4 degrees 5 and 6, respectively. A stopper pin 71 can be depressed into each of the grooves, and when the pin 71 falls into and engages the groove, the rotation of the support plate 11.12 is stopped. So Jiang 67 is Bin 7
When the groove 68 is engaged with the pin 71, the gear group 4 is;
When #I70 engages with pin 71, gear group 5 is positioned at the operating position, and when #I70 engages with pin 71, gear group 6 is positioned at the operating position.

The bin 71 is mounted on a lever 72 that is supported so as to be swingable about a shaft 73 provided at a fixed position.

A spring 74 is applied between the lever 72 and the bin 75 provided at a fixed position, and this biases the lever 72 counterclockwise to keep the stopper bin 71 constantly on the support plate 1.
It is elastically biased in one direction.

The drive plate 62 has four protrusions 76 , 77 , 78 corresponding to the four grooves of the support plate 1104.

79 are provided. The front portion of each protrusion in the rotational direction R is sloped 76', 77', 78, 79.
'. As a result, when the drive plate 62 rotates in the direction of arrow R with the support plate 11 fixed and the slope of the protrusion comes into contact with the stopper bin 71 engaged with the groove of the support plate 11, the stopper bin 71 is rotated. The cam action of this slope causes it to be pushed up from the groove against the elastic force 740, allowing it to escape outside the premises. Thus the support plate 11°12
The stopped state of is released and it becomes possible to rotate about the shaft 31 in the direction of arrow R.

On the outer periphery of the control ring 42 of the spring clutch 41, there is a pawl 44t corresponding to the gear group ",'s"r6Vc.
44t, 44m+444 are provided at intervals in the direction of the rotation axis of the control ring 42. Since the shafts 7+8+9+10ij of the gear group are provided at 90 degree intervals on the support plates 11 and 12, the claws 44. -444 are also provided on the ring 42 at the same intervals, approximately 90 degrees apart, but if the above-mentioned shafts 7-10 are installed at intervals other than the above-mentioned angle, the installation intervals of the pawls 441-444 are also set at the same intervals. Make it correspond. Similar to this, the groove 67 provided in the support plate 11
70, the same can be said of the protrusions 76 to 79 provided on the drive plate 62. In any case, the spring clutch 41 is activated to connect the gear 40 and the shaft 31, and when the shaft 31 rotates, the control ring 42 also rotates. Therefore, the claw 44. -444 comes into contact with the control stopper 60, the control ring 42
rotation is stopped. Although the barbs 45 that stop the rotation of the control ring 42 are loosened, the connection between the gear 4° and the shaft 31 is severed, and therefore the rotation of the drive plate 62 is also stopped. Note that when gear group 3 is in the operating position, the pawl 441 is in the operating position, and when gear group 4 is in the operating position, the pawl 44. However, when the gear group 5 is in the operating position, the pawl 443 is in contact with the stopper 60, and when the gear group 6 is in the operating position, the pawl 444 is in contact with the stopper 60.

As shown in FIG. 8, the control lever 60 is provided on a lever 80 rotatably supported on a shaft 81 provided at a fixed position within the device. The lever 80 has an operation knob 8
2 is provided, and by moving this knob 82 in the direction of the arrow, the operator can rotate the lever 80 in the direction of the arrow and displace the position of the stopper 60 in a substantially parallel direction. In this way, the operator can move the stopper 60 to a position where it can be engaged with a claw corresponding to the selected document f-image forming magnification.

Note that along the moving path of the knob 82 there is a scale, 983. ~834
is engraved. Scale #) 831 to 832 are claw 4 respectively.
4, ~444 (6 claws 44.~444 are original image forming magnification m
1 to m4). (Therefore, they correspond to gear groups 3 to 6, respectively.) Then, the knob 82 is set to a scale 83. which corresponds to the magnification m, for example. The scale 83. corresponds to the magnification m3 from the position. If it is displaced to the position, the stopper 6
0 is a displacement from the position where it was engaged with the claw 442 to the position where it can be held with the claw 443. Next, the operation of the above mechanism will be explained.

The control stop 60 is removed from the control ring 42 with which it was engaged.
, and displace it to a position corresponding to the desired document 1 tearing magnification, and the claw 59 described below controls the control R42.
Nail 43. 434, the spring 45 transmits the driving force from the motor 20 to the drive plate 62. At the same time, the control ring 42 rotates. The rotation continues and the control ring pawl 44. When one of gear ratios corresponding to the selected speed ratio is engaged, the spring 45 is loosened, the transmission of driving force from the gear 40 to the shaft 31 is cut off, and the rotation of the drive plate 62 is stopped. This quickly completes the changing operation.

On the other hand, when the gear group corresponding to the desired magnification is located at the operating position, the state is as shown in FIG. Start rotating in the direction. However, the support plate 11 cannot rotate yet because the stopper pin 71 is engaged with the groove. Meanwhile, the drive plate 62 continues to rotate while stretching the spring 66. Next, one of the protrusions provided on the drive plate 62 engages with the bottle 71, and as the drive plate 62 rotates, the protrusion pushes the bottle 71 out of the groove of the support plate 11. The elongated hole 64 has a length sufficient to enable the above-mentioned movement of the drive plate 62,
5 is arranged only in the opposing gap between the drive plate 62 and the support plate 11, and the spring 66 is supported within this opposing gap, the elongated hole 64 is naturally unnecessary.

In any case, when the stopper bottle 71 is kicked out of the groove of the support plate 11, the support plate 11 rotates in the direction of arrow R due to the elastic force stored in the spring 66, and the bottle 71
rests on one circumferential portion of the support plate 11. At this time, the gear group that was in the operating position is removed from the operating position. The support plate 11 continues to rotate in the direction of arrow R by the drive plate 62 via the spring 66, as shown in FIG. As the rotation continues, the next groove of the support plate 11 comes to a position where it engages with the bottle 71, and the bottle 7
1 falls into the groove due to the action of the spring 74, and the support plate 11,
The rotation of 12 stops. This positions the next gear group in the operating position, but the pawl on the control ring 42 has not yet reached the position where it engages the stopper 60. Therefore, the driving force transmission from the gear 40 to the shaft 31 is not cut off yet.
The drive plate 62 continues to rotate with respect to the stopped support plate 11 while stretching the spring 66. Then stopper 6
0 is located in the rotation path of the next pawl on the control ring, the pawl engages with the stopper 60 before the protrusion next to the drive plate 620 kicks out the stopper pin 71 from the groove of the support plate 11. Then, the spring 45 is loosened, the transmission of driving force from the gear 40 to the shaft 31 is cut off, and the rotation of the drive plate 620 is stopped. If the newly selected gear group is one gear group next to the previously selected gear group in the direction opposite to the arrow R, the speed switching operation ends as described above.

However, if the newly selected gear group is different from the gear group described above, the stopper 60 is not in the rotation path of the control ring pawl corresponding to the newly selected gear group, so the stopper bin 71 is Even if the bottle 71 falls into the groove 11, the operation of the spring clutch 41 does not stop, the drive plate 62 continues to rotate, and the next protrusion kicks the bottle 71 out of the groove. The above operation is repeated until the control ring pawl corresponding to the newly selected gear group comes into contact with the stopper 60 and the spring clutch 41 stops operating.

In this way, by positioning the support plate 11 and thus the gear group before stopping the operation of the spring clutch 41, it is possible to prevent the shaft 31 by the spring clutch 41 itself.
The selected gear group can be accurately and reliably held in the operating position even if the stop positioning accuracy is low.
A desired document scanning speed can be obtained smoothly and with high precision.

In the above example, the drive plate 62 is directly fixed to the shaft 31, but the rotational driving force of the shaft 31 may be transmitted to the drive plate 62 via a gear train or the like.

In the above embodiment, the output shaft 23 can be rotated in both forward and reverse directions, and the rotational speed in the forward direction can be changed. Therefore, in this embodiment, when the shaft 23 rotates in the forward direction, even if the lever 83 is operated to change the position of the stopper 60, the speed changing operation described above is not performed.

That is, in FIG. 5, the control ring 42 of the spring clutch 41 has the following:
Said claw 44. ~44. At a position apart from the claws 43., corresponding to each of the gear groups 3 to 6, respectively. ~434 are provided. These pawls 43° to 434 are arranged on the same circumference of the ring 42 so as to pass through the same path when the ring 42 rotates, and when the gear group 3 is in the operating position, the pawls 43 , when gear group 4 is in the operating position, pawl 43. When gear group 5 is in the operating position, pawl 4
3. When gear group 6 is in the operating position, pawl 434
The claws 59 are adapted to engage with the respective ones.

The pawl 59 is provided on a lever 84 that is rotatably supported on a shaft 85 provided at a fixed position. This lever 8
4 is rotatably pivoted to the link plate 80. A lever 86 is also rotatably pivoted to the link plate 80. This lever 86 has a control type wheel 37 of the spring clutch 36.
A control pawl 58 is provided which engages with the control pawl 58 and is rotatably supported on a shaft 87 provided in a fixed position.

The link plate 80 is urged rightward by a spring 87. Therefore, this spring 87 moves the pawls 59 and 58 to the control ring 4.
The pawl of No. 2 is biased in the direction of separating from the pawl of the mold wheel 37. On the other hand, an electromagnetic plunger 88 is connected to the link plate 80, and when the plunger 88 is activated, the pawls 59 and 58 resist the elastic force of the spring 87 and move the control ring 42. The pawl enters in conjunction with the position in the rotation path of the pawl of the mold wheel 37. When the plunger 88 is deenergized, the claw 59
．． 58 are respectively retracted out of the above-mentioned path. When the pawl 59 is retracted out of the above-mentioned path and the stopper 60 is not engaged with any pawl, the spring clutch 41 is connected and the driving force of the gear 40 is transmitted to the shaft 31. , the claw 59 is the same as the claw 43. 434, the spring clutch 41 will not operate even if the stopper 60 is not engaged with any pawl, and the driving force of the gear 40 will not be transmitted to the shaft 31. Further, when the pawl 58 is retracted from the model wheel 37, the spring clutch 36 stops operating and the motor 20
The transmission of the driving force from the drive force to the gear 35 is cut off, and the forward rotation of the shaft 23 is stopped. Conversely, when the pawl 58 engages with the mold wheel 37, the spring clutch 36 is activated, and the shaft 23 is rotated in the forward direction. Rotate to.

10,000, a control type wheel 55K of a spring clutch 54 for transmitting rotational driving force in the reverse direction to the shaft 23;

The lockable control pawl 61 is mounted on a lever 89 which is rotatably supported on a shaft 90 provided in a fixed position, and the pawl 61 is directed by a spring 91 in the direction of withdrawal from the rotation path of the mold wheel 55. is energized by An electromagnetic pusher 92 is connected to the lever 89), and a plunger 9
2 is activated, the pawl 61 engages with the mold wheel 55 against the elastic force of the spring 91, and the spring clutch 54 is activated. On the other hand, when the plunger 92 is deenergized, the claw 61 is separated from the mold wheel 55 by the spring 91, and the operation of the spring 2-touch 54 is stopped. In other words, the rotation of the shaft 23 in the reverse direction also stops.

As described above, when the plunger 88 is energized, the plunger 92 is deenergized, the shaft 23 is rotated in the normal rotation direction, and the document scanning means is moving in the direction of arrow A, the pawl 59 is activated by the control ring. Nail 43. 434, even if the lever 8o is operated to change the position of the stopper pawl 60, the spring clutch 41 will not operate, and therefore the gear group support plate 11, 12 will not rotate. However, when the plunger 88 is energized from the above state, the plunger 92 is deenergized, the rotation direction of the shaft 23 is changed to the reverse direction, and the document scanning means is moved in the direction of arrow B, the claw 59 is Since it comes off from the control ring pawl, if the stopper pawl 60 is displaced while the scanning means is moving in the inward direction, or if the stopper pawl 60 is displaced while moving in the direction of arrow B, the spring clutch 41
is actuated and the shaft 31 begins to rotate, thereby bringing the gear group corresponding to the selected transmission ratio into the operating position.

In addition, when both the plungers 88 and 92 are deenergized, neither the forward rotational driving force nor the reverse rotational driving force is transmitted to the tab shaft 23, and the document scanning means is at the starting position of movement in the A direction, the claw is 59 is either claw 43. 434, so when the lever 80 is operated to change the position of the stopper 60, the gear group corresponding to the folded position of the stopper 60 is brought to the operating position as described above.

In this manner, in this embodiment, when the document scanning means is moving in the B direction or stopped at the starting point position of the backward movement, the speed switching operation for the A direction movement is performed.

In FIG. 4, reference numeral 93 denotes a cam ring which is fixed to the shaft 31 and rotates in conjunction with changes in the positions of the gear groups 3-6. The cam 93 may be connected to the shaft 31 via a gear train or the like. In any case, the shape of the cam n94 of the cam 93 corresponds to the respective positions of the gear groups 3 to 6. Therefore, the position of the cam follower 95 engaged with this cam groove 94 is
For example, a sliding variable resistor 96 connected to this follower,
When detected by a plurality of microswitches arranged along the moving direction of the follower 95, a signal corresponding to the gear group positioned at the operating position, and thus corresponding to the selected original image forming magnification, can be generated. can.

In FIG. 4, the variable resistor 96 is interposed between the power supply 97 and the document illumination lamp 109 or 109', and the output of the lamp 109 or 109' is changed in accordance with the selected document image forming magnification; The amount of exposure of the original light image on the photoconductor is made to be substantially constant for any magnification.The above signal may be used, for example, to display the set original image forming magnification, or to change the setting of the zoom lens 103. It can also be used as a control signal for a servo motor that moves the signal to a position corresponding to the magnification. In addition, as a means for forming the above signal, a cam or a light shielding piece is provided on the support plate 11 or 12 at a position corresponding to each gear group, and - a micro switch or a photo shield corresponding to the cam or light shielding piece is provided. Obtaining the signal corresponding to the gear group positioned in the operating position also by other means, such as fixing the couplers in their respective positions and activating each microswitch or photocoupler with each cam or light-shielding piece. I can do it.

In FIG. 9, the driving force of the cam 93 is applied to the zoom lens 103.
An example has been shown in which the lens 103 is mechanically transmitted to a position corresponding to the selected magnification, and the lens focal length is set to a value corresponding to the selected magnification.

In FIG. 9, the zoom lens 103 is provided within a lens barrel 123. A zoom ring 124 having a helical tooth pinion carved on its outer periphery is fitted into the lens barrel 123 so as to be rotatable relative to the lens barrel 123 . A long hole 125 provided in a protruding piece of the ring 124 is engaged with a pin 126 provided in a focal length adjusting lens element in a zoom lens. This bottle is inserted into a cam hole 127 provided in the lens barrel 123. Therefore, if the ring 124 is rotated, the bottle 12
6 moves relative to the lens barrel 123 in the lens optical axis direction;
This changes the focal length of the lens.

The lens barrel 123 is fixed to a lens stand 128. A hole 129 is provided in a part of the base 128, and the helical tooth pinion of the zoom ring 124 meshes with the helical tooth rack 130 fixed to the base 140 through the hole 129. Therefore, when the stand 128 is moved along the guide rail 131 fixed to the base 131C, the rack 1
The reaction of 30 causes the binion and therefore the zoom ring 1
24 rotates, and the focal length of the lens changes as described above. Note that 132 is a sliding bearing fixed to the lens stand 128, and is slidably fitted to the rail 131.

A long hole 133 is provided in the lens stand 12B in a direction intersecting (for example, perpendicular to) the direction of movement thereof, and a lens is rotatably supported in the long hole 133 by a shaft 134 provided at a fixed position. The bottle 1 provided at the tip of the lever 135
36 is inserted. A U-shaped groove 137 is provided at the base of the lever 136, into which one end of a lever 139 rotatably supported on a shaft 138 provided in a fixed position is slidably fitted. are combined. The other end of the lever 139 is attached to the shaft 31 and therefore engages in a cam groove 94 of a cam cylinder 93 that rotates when rotating the support plate 11.12 of the gear group. Therefore, when the cam cylinder 93 is rotated, the lever 139 is rotated as shown by the arrow around the shaft 138. At this time, one end of the lever 139 presses the U-shaped groove of the lever 135, so that the lever 135 rotates around the shaft 134. Rotate around the center as shown by the arrow.

The lens stand 128 is pushed by the pin 136 provided at the tip of the lever 135, and the lens stand 12B and therefore the lens 103 move along the rail 131, and in conjunction with this movement, the lens focal length also changes. do.

The cam groove 94 has each gear group 3°4.5.
4 positioning portions 94m corresponding to 6, respectively.

There are 94t t 94s + 944 (only 94□ is shown in the figure). The tip of the lever 139 is connected to the positioning portion 94. When the lens 103 is engaged with the above-mentioned P.

In position, 94. When engaged, it is in the P7 position, 94. When engaged with Fip, in position 94. P when engaged.

and the focal length of the lens 103 is changed corresponding to each position at which the lens is positioned. Each positioning portion 94 of the cam groove 94. -944 are parallel to the movement direction of the cam (rotation direction in this case), and each have a required length in the cam movement direction. Each part 94. The above length of ~944 is determined by taking into account the positioning error of the shaft 32 by the spring clutch 41, and is determined by the amount of rotation of the shaft 32 when positioning the gear group corresponding to the selected magnification at the operating position. The lever 139 has a length sufficient to prevent the lever 139 from shifting from the position corresponding to the selected magnification of the cam groove 94 even if a maximum error occurs due to an operating error of the spring clutch 41. It is preferable that (The cam groove 94 in Fig. 4
Parallel groove portions 941 to 94 above. (It is desirable to provide a will be changed to correspond to the magnification.

Alternatively, the cam cylinder 93 may not be used, and the lever 139 may be driven by providing a pinion on the shaft 32, engaging a rack that moves linearly with the pinion, and fixing a cam plate to this rack.

In the above example, all the first gears of the driving force transmission gear group are always in mesh with the input side gear. Although this is preferable in terms of smooth gear shifting operations, it is not always necessary.

In the embodiment shown in FIG. 9, the zoom lens is driven by a cam 93 fixed to the shaft 31.
The zoom lens may be driven by a cam (which starts and stops at the same time as the support plate 11 starts and stops, and moves at a speed that is a constant ratio to the movement speed of the support plate 11 during movement). For example, as shown in FIG. 4, the support plate 12 that rotates integrally with the support plate 11 is a cylindrical cam, and a cam groove (94) is provided around the cylindrical cam. Then, the lever 139 shown in FIG. 9 is engaged with this cam groove (94). This lever 139 is used to move the zoom lens and change the focal length through a mechanism similar to that shown in FIG. Note that a gear may be provided on the outer periphery of the support plate 12, and the zoom lens may be driven by a cam that is synchronously interlocked with this gear via a gear train. In any case, since the support plate 11 is accurately positioned in accordance with the selected magnification, the parallel cam grooves 94, such as those provided in the cam 94 shown in FIG. ~94
4 may not be provided.

Further, when a fixed focus lens is used as the lens, when changing the document image projection magnification, it is necessary to change the optical path length between the document and the lens in addition to changing the position of the lens. At this time, it is common to change the position of a mirror (for example, 104 in FIG. 1.2) constituting the projection optical system, but the above mechanism can also be used to change the position of such a mirror.

For example, attaching a mirror to the stand 128 in FIG. 9. Alternatively, cams as described above may be provided for lenses and mirrors, respectively, and the positions of the lenses and mirrors may be changed.

Further, in the above-mentioned embodiment, the pin 71 shown in FIGS.
The protrusions 76 to 79 provided in the grooves 67 to 7 of the support plate 11
Although the pin 71 is kicked out from zero, the pin 71 may be pulled out from the groove by other means such as an electromagnetic plunger. For example, 141, 142 shown by two-dot chain lines in Figure 6
, 143 are a microswitch, a timer, and an electromagnetic plunger, respectively, and the microswitch 141 is connected to the drive plate 62.
is acted on by projections 76 to 79 provided corresponding to each of the gear groups 3 to 6. Therefore, in this case, the protrusion 7
Reference numerals 6 to 79 are switch actuating members, not bottle kicking members, so they are provided so as to move to a position where they do not come into contact with the bottle 71. In the microswitch 141, after the spring clutch 41 is activated and the drive plate 62 starts rotating in the direction of arrow R, the pin 71 of the protrusions 76 to 79 is fitted when the spring 66 is slightly stretched. The opening is actuated by a projection corresponding to one of the grooves 67 to 70 of the support plate 11 and is closed. A signal from the switch 141 at this time is applied to a timer 142, and the timer 142 operates the electromagnetic plunger 143 for a predetermined time from the time when the switch 141 is closed.

This plunger 143H is mechanically connected to the lever 72, and when activated, the lever 72 is rotated clockwise against the elastic force of the spring 74, and the bottle 71 is retracted from the groove, thereby causing the support plate 11 and start rotating in the same manner as above. Due to the rotation of the support plate 110, the groove in which the bottle 71 was engaged moves from the engagement position with the bottle 71, and before the next groove comes to the engagement position with the bottle 71, the timer 1 is activated.
42 is deenergized, causing the plunger A1430 to stop operating. As a result, the bottle 71 is pressed against the surface lr of the support plate 110 by the elastic force of the spring 740. When the next groove reaches the position where it is engaged with the bottle 71, the bottle 71 falls into this groove and the rotation of the support plate 11 is stopped.

As described above, the selected gear group is positioned at the operating position, the locking pawl 60 comes into contact with the control ring protrusion (44, to 444) corresponding to the group, and the spring clutch 42 is turned off. repeated until the force is applied.

In addition, the drive plate 62 is attached to the micro switch 1410 9.
It is also possible to use a photocoupler or the like consisting of a light-emitting element and a light-receiving element facing each other, arranged so that the optical path between them is blocked by each protrusion.

Furthermore, in the above embodiment, the pitch circle of the input gear 1 is inscribed in the circle CI, and the pitch circle of the output gear 2 is circumscribed in the circle C1, but the pitch circle of the output gear 2 is also inscribed in the circles CI. (in this case, the pitch circle of each second gear circumscribes the virtual circle C2), or the pitch circle of input gear 1 may also circumscribe the circle C1 (in this case, the pitch circle of each gear 1 circumscribes the virtual circle C2). The circle is inscribed in the virtual circle CI). An example of the former is shown in FIG. 10, and an example of the latter is shown in FIG. 11. In any case, the support plates 11 and 12 of each gear group are located at the common center X of the circles C1jC2.
Rotates around the axis.

In addition, although the above embodiment has shown an ideal example in which the pitch circles of the first gear and the second gear of the gear group are inscribed or circumscribed, respectively, with the virtual circle C, C, each first gear, There is no need for the pitch circle of the second gear to be strictly inscribed or circumscribed in each virtual circle, and there is no need for the pitch circle of the input side gear to be strictly coincident with, or inscribed or circumscribed with, the virtual circle C. Furthermore, the pitch circle of the output gear does not need to be strictly circumscribed or inscribed with the virtual circles, and when each gear group comes to the operating position, the first gear of that gear group becomes the input gear, and the second gear It suffices if the gear is engaged with the output gear. That is, the input side gear is in the position and does not prevent the movement of each first gear, but meshes with the first gear of the gear group that has come to the operating position, while the output side gear is in the support plate 11° 12 It is located outside or inside the movement path of the second gear of each gear group when it rotates, and does not prevent the movement of each second gear, but the second gear of the gear group that has come to the operating position It only needs to be in a position where it meshes with the gear. Together with the arrangement of each gear and the strictly inner and circumscribed states described above, the pitch circles of each first gear, each second gear, input side gear, and output side gear are concentric virtual circles. It can also be said that it is substantially inscribed or circumscribed in C.

Further, in each of the above embodiments, 1 is the input side gear and 2 is the output side gear, but these may be replaced so that 2 is the input side gear and 1 is the output side gear.

In this case, the gear designated as the first gear in each gear group is read as the second gear, and the gear designated as the second gear is read as the first gear. In this case, the same means as described above can be used as the means for transmitting the driving force to the first gear and the means for outputting the driving force from the second gear.

Furthermore, only the position of the optical member may be changed via a spring clutch, or only the position of the gear group of the transmission mechanism may be changed.

In addition, the selectable document image formation magnification is 3 or 4 in the above example.
However, it may be 2, or 5 or more.

Furthermore, the present invention does not only use an electrophotographic photoreceptor, but also uses a photoelectric conversion element such as a so-called CCD as a photoreceptor, which converts an optical image into an electric signal corresponding to the image, and uses the formed electric signal to generate an image. It can also be used in the document scanning device of the forming device.

In any case, according to the present invention, although the movable body for changing the document image forming magnification is driven via a spring clutch, the movable body can be accurately positioned, so that a good document image can be obtained at the selected magnification. can be formed.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of an example of a copying apparatus to which the present invention can be applied, FIG. 3 is a partial explanatory diagram of a document scanning speed changing mechanism, and FIG.
The figure is a partial explanatory diagram of the arrow A-A in Figure 3, FIG. 5 is a partial explanatory diagram of the arrow in FIG. 7 is a perspective view of the portion shown in FIG. 7, FIG. 9 is an explanatory view of an example of a lens drive mechanism, and FIGS. 1O and 11 are explanatory views of other examples of a speed switching mechanism. 3.4, 5.6 are drive power transmission gear groups for speed change, 11
is a support plate, 20 is a drive motor, 41 is a spring clutch, 6
2 is a drive plate, 71 is a stopper pin, 94 is a cam groove, t
Oa is a lens.

Claims (6)

[Claims] (1) In a variable magnification image forming device that forms a document image at a selected magnification, a movable body that is moved to a position corresponding to the selected magnification in order to change the magnification of the document image to be formed; a drive member that drives the movable body; a spring clutch means that transmits a driving force from a drive source to the drive member when changing the document image forming magnification; a spring clutch control means for selectively connecting/disconnecting the clutch means; and a spring clutch control means for selectively engaging and disengaging the clutch means, while the driving force from the drive source is being transmitted to the drive member via the spring clutch means, for controlling the movable body to correspond to a selected magnification. A variable magnification document image forming apparatus, comprising: a positioning means for stopping at a certain position. (2) The positioning means has a retaining member elastically biased to the movable body, and the movable body has a retainer that stops its movement when the engaging member engages therewith. The driving member has a mating member locking portion, the driving member is connected to the movable body via an elastic member, and when changing the position of the movable body, the driving member is disconnected from the retaining member locking portion of the movable body. The variable magnification original image forming apparatus according to claim 1, further comprising a kick-out portion for kicking out the mating member. (3) The positioning means has a retaining member elastically biased to the movable body, and the movable body has a retainer that stops its movement when the engaging member engages therewith. a mating member locking portion, the driving member is connected to the movable body via an elastic member, and the positioning means further moves the engaging member to the movable body when changing the position of the movable member. The variable magnification original image forming apparatus according to claim 1, further comprising means for removing the retaining member from the retaining member of the body. (4) The control ring of the spring clutch has a plurality of retaining portions corresponding to respective positions at which the movable body can be positioned, and the spring clutch control means is capable of engaging and disengaging from the engaging portion. The variable magnification original image according to claim 1, comprising a locking portion and means for engaging the locking portion with a control ring engaging portion corresponding to a selected positioning position of the movable body. Forming device. (5) The variable magnification according to any one of claims 1 to 4, wherein the movable body is connected to a speed change gear means of a speed change means for driving the document scanning means at a speed corresponding to a selected magnification. Original image forming device. (6) The variable magnification original image forming apparatus according to any one of claims 1 to 4, wherein an optical member constituting an optical system for projecting an original image onto a photoreceptor is connected to the movable body.