JPS60165634A - Original scanning device - Google Patents

Abstract

PURPOSE:To vary an original scanning speed securely and smoothly with simple constitution by switching gears having different gear ratios to an output side gear selectively by using a specific positioning means when copy magnifications are changed. CONSTITUTION:Support plates 11 and 12 are supported rotatably on a shaft 31 to which the turning force of a driving motor 20 is transmitted and gear groups 3-6 which have different gear ratios and correspond to magnifications m1-m4 are arranged concentrically. Raised claws 441-444 corresponding to the magnifications m1-m4 are provided to the control ring 42 of the spring clutch 41 of the shaft 31. When a desired copy magnification is set, the support plates 11 and 12 rotate to control the selected raised claw with a control stopper and also engage the specific gear group with the output-side gear 2, locking the support plates 11 and 12. Then, the turning force is transmitted to a pinion 112 to drive an original platen at a desired speed. Thus, original scanning speeds are changed securely with the simple constitution.

Description

[Detailed description of the invention] The present invention relates to a document scanning device.

In a copying apparatus or the like in which the original image forming magnification is variable, the original scanning means changes the magnification in accordance with the selected magnification. For example, if a movable photoreceptor is used and the speed of this photoreceptor is V, then
When the selected magnification is m, the document scanning speed is set to V/m.

By the way, in the above variable speed document scanning device, in order to move the document scanning means at a desired speed by the driving force from the drive source, conventionally an electromagnetic clutch is used to select a gear train corresponding to a desired speed ratio. Transmission devices that actuate the transmission are often used, but such devices require the same number of electromagnetic clutches as the number of selectable speed ratios, resulting in larger and more expensive devices.

On the other hand, the transmission disclosed in Japanese Unexamined Patent Publication No. 57-83749 does not require electromagnetic clutches, or even if they are used, the number of them can be reduced. They are arranged on one shaft, and the output side gears are also arranged on one shaft, so they can be selected.As the number of gear ratios increases, the shaft length increases, and the driving torque increases. If it is too large, the intermediate part of the shaft will be deflected, making it difficult for the gears to mesh smoothly, causing wow and flutter, and causing distortion and distortion in the formed image, deteriorating the image quality. Put it away.

SUMMARY OF THE INVENTION An object of the present invention is to provide a document scanning device that can overcome the drawbacks of the above-mentioned conventional devices.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 and FIG. 2 are explanatory diagrams of examples of electrophotographic copying apparatuses to which the present invention can be applied. However, the present invention is not limited to this, and may be an endless belt 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 optical image is formed onto the photoreceptor 101 by the zoom lens 103. The zoom lens 103 is then displaced to a position corresponding to the magnification selected by the magnification changing operation by known means, and changed to a focal length corresponding to the selected magnification in conjunction with the movement. be done.

In the figure, P and -P4 are the positions of the zoom lens 103 when the document image forming magnification is m1 to m4, respectively. A light beam from the document exiting the lens 103 is reflected by a 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 photoconductor 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 original 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. A latent image of the original is formed. When the document scanning is completed, the document table 110
moves backward in the direction of arrow B and returns to the starting point of movement in the direction of arrow B.

A rack 111 is fixed to the document table 110.

A pinion 112, which will be described later, is engaged with this rack 111, and by rotating the pinion 112 in the direction of arrow C (normal rotation direction), the document table 110 is moved in the direction of arrow A.
Further, by rotationally driving in the direction of the arrow (reverse direction), the document table iio is moved in the direction of the arrow B. 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 as described above. That is, the table 110 is moved in the direction indicated by the arrow at a speed equal to the moving speed of the circumferential 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. The pinion 112 is therefore driven in rotation in the direction of the arrow C at a speed corresponding to the selected magnification and moves the platform 11.1 at said speed in the direction of the arrow.

The moving speed of the table 111 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 rotation speed of the pinion 112 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 the driving force may be transmitted to the document table using a wire, a pulley mechanism, etc. instead of the rack and hinion mechanism described above. In the apparatus shown in FIG. 2, the document table 110' is fixed at a fixed position. The original is scanned by moving the mirror.

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

The above-mentioned mirror 113 and mirror 114. 115 is moved at a speed ratio of 2:1 in order to keep the optical path length between the original and the lens constant, and the drive mechanism, which is also often used in this case, uses the principle of a movable pulley. That is, 118 is M2
It is a pulley (moving pulley) rotatably attached to the mirror unit 117.

Reference numeral 119 is a wire for transmitting driving force, and after locking one end 119' to the main body of the device, it is hung on the pulley 118 and folded back, hung on a boo 17120 provided at a fixed position and folded back again, and once connected to a drive boo 11J121, which will be described later. After wrapping it several times, it is hung on a pulley 122 provided at a fixed position and then folded again.
Then, after it is hung on the booth IJ 118 and folded back, the other end 11 (1") is locked to the main body of the apparatus. The first mirror 116 is fixed to the wire 119 between the booth IJ 118 and 120. In order to scan, drive IJ1
21 is rotated in the direction of arrow C (normal rotation direction), the mirror 113° lamp 109' and the mirror 1.14. 115
moves in the direction of the arrow at a speed ratio of 2:1. At this time, the light flux from the oak 1a illuminated by the lamp 109 is reflected by the mirror 113.
, 114° and 115 in order, and the zoom lens 1
The photoreceptor 101 is exposed through the 03° mirror 104 as described above to form an electrostatic latent image of one document. When scanning of the original is completed, the drive IJ121 is rotated in the direction of the arrow (reverse direction), and the mirror 113, lamp 109' and mirror 1 are rotated.
14. 115 moves back in the direction of arrow B at a speed ratio of 2:l and returns to the starting point of movement in the direction of each arrow. Therefore, the moving speed of the mirror 113 in the arrow direction (original set feeding speed)
is changed in accordance with the document image formation magnification selected as described above.

That is, the mirror 113 and the lamp 109' are therefore
6 is moved in the direction indicated by the arrow at a speed obtained by dividing the moving speed of the circumferential surface of the photoreceptor 1010 by the selected image forming magnification. Therefore, the drive boolean 17121 is rotationally driven in the direction of the arrow C at a speed corresponding to the selected magnification, and rotates the table 116 and thus the mirror 113.

The ramp 109 is moved in the direction indicated by the arrow at the above speed.

of the pedestal 116 and hence the mirror 113 . The moving speed 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 speed at which the drive pulley 121 rotates in the direction indicated by the arrow may be the same for any magnification, or may be changed depending on the selected magnification. Note that even if the speed of the mirror 113 is changed, , mirror 114. 115 moves at a speed of % 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 is also applicable to those using a custom document feeder that scans a document by conveying the document through a position. Therefore, in this specification, the document scanning means is a general term for those that move for document scanning, such as the OT moving document table, movable optical members such as a movable mirror, and the document conveyance roller or belt.

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

FIG. 3 is an explanatory diagram of a main part of an embodiment of the present invention, and to avoid complexity, each gear is shown with its own pitch circle. Fourth
The figure is an explanatory diagram of a part of the apparatus seen in the &-A direction of Figure 43. In each figure, 1 is an input gear located at a fixed position, 2 is an output gear located 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 3 and 4°5' respectively
, 6' and second gear 3. 4. 5. 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 l, but there is no need to limit it to this.

In any case, the gear ratio of the first gear and the second gear of gear group 3 is the original image forming magnification m, that of gear group 4 is m, that of gear group 5 is m, and that of gear group 6 is m4, respectively. Still Figure 3,
In the example shown in FIG.

The first gear and second gear of each gear group 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.
1.12 supported shaft 7. 8. It is rotatably supported at 9°10. Axis 7, 8. .

Reference numeral 9.10 is a common shaft for the first and second gears supported by each, but on the other hand, support plates 11.12 are integrally and fixedly connected at intervals that accommodate each gear. It also serves as a connecting member. Here, the support plates 11, 12 are rotatable in the direction of arrow R in FIG. 3 (or in the opposite direction) by a mechanism to be described later, and the gear groups 3, 4, 5.
6 indicates support plates 11 and 12 at intervals in the rotation direction.
supported above. The above-mentioned intervals can be set arbitrarily as long as the gear groups do not interfere with each other, but in the illustrated example, the shafts 7, 8, 9.10 of each gear group are sequentially attached to the support plate 11.12 at intervals of 90 degrees. Fixed.

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

The pitch circles 4', 5', and 6' circumscribe one common virtual circle C1. In the illustrated example, the circle C2 is the pitch circle of the input gear l. On the other hand, the second gear 3 of each gear group.
4. 5. The pitch circle of 6 is another common virtual circle C
2, and the pitch circle of the output gear 2 is circumscribed to this circle C7.

The imaginary circles C, , C, are concentric circles, and the support plates 11.12 rotate around the axis located at the center of the imaginary circles C, , C,. Thus, the first gear 3 of each gear group. 4', 5', and 6' are always in mesh with the input side gear l no matter what rotational position the support plate 11.12 is stopped at, and even when the support plate 11.12 is rotating. It revolves around the axis of the support plate 11, 12 while meshing with the gear 1. and the second gear 3 of each gear group. 4. 5. 6 meshes with the output side 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 transfers the driving force from the input gear l to the output side gear through the first gear and then the second gear. to communicate. 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. .

Now, in FIG. 4, the input side gear 1 is fixed to the shaft 13. This shaft 13 is rotatably supported by a device frame plate 15 via a bearing 16.

The shaft 13 is still fitted into a bearing 17 provided on the support plate 12 of the gear group, and is rotatable relative to the support plate 12. Numeral 18 is a toothed pulley fixed to the shaft 13, and is rotationally driven by a toothed bell (19) which is rotated by a driving force from a drive motor 2o such as a DC motor. When the motor 20 operates, the gear l becomes a bell) 19. Pulley 18. It is rotationally driven through the shaft 13, and this rotational driving force is transmitted to the output side gear 2 through the driving force transmission gear group in the operating position. Each gear group 3. 4. 5.6 has different gear ratios for the first gear and the second gear as described above, so even if the input gear 1 is rotated at a constant speed, the output gear 2 is rotated by the gear group in the operating position. It is rotated at a speed corresponding to the gear ratio of the first gear and the second gear. Therefore, the gear 2 is connected to the device frame 1.
4.15 is fixed to a shaft 23 which is rotatably supported via bearings 21 and 22, and this shaft 23 has the aforementioned pinion 112 (Fig. 1) or drive boolean IJ 121 (Fig. 2). Fixed. Thus, when the gear 2 rotates, the binion 112 or the pulley 121 also rotates, and the document scanning speed is a speed corresponding to the selected document image forming magnification.
In other words, it is driven at a speed corresponding to the gear ratio of the first gear and second gear of the gear group in the operating position.

In the apparatus shown in FIG. 4, the document table 110 shown in FIG. 1 is used.

To move the mirrors 113, 114, and 115 in FIG. 2 in the direction indicated by the arrow, the motor 20 is driven to rotate in the forward rotation direction, while to move the mirrors 113, 114, and 115 in the direction of arrow B, the motor 20 is rotated in the reverse direction. Therefore, if the apparatus shown in FIG. 44 is used, the document table 1101 mirrors 113, 114,
The speed of movement in the direction of arrow B of 115 will also change in accordance with the selected magnification, but in order to quickly return the above-mentioned member to the starting point of forward movement after scanning the original, the speed in the direction of arrow B is changed. It is desirable that the rotation speed of the motor 20 in the reverse rotation direction be greater than the rotation speed of the motor 20 in the forward rotation direction, such that the rotation speed of the motor 20 is greater than the speed in the direction of the arrow.

As shown in FIG. 4, the support plate 11 of the gear group is
A shaft 2 rotatably supported by the frame 14 via a bearing 26
It is fixed at 5. The shaft 25 is rotationally driven by a pulse motor 24.

This pulse motor 24 operates when changing the rotational speed of the output side gear 2, that is, when changing the original scanning speed, and rotates the support plates 11 and 12 to correspond to the selected original image forming magnification. bring the gear group into operating position. A brake 27 operates when the gear group corresponding to the selected document image forming magnification comes to the operating position, when the motor 24 stops and the shaft 25 is fixed, and the gear group corresponding to the selected magnification is activated. When transmitting the driving force from gear 1 to gear 2, the position of this gear group is reliably prevented from changing. However, the brake 27 is not necessary when there is no risk of displacement of the gear group during operation, such as when the rotational load on the support plates 11, 12 is large. Further, instead of the brake 27, a positioning mechanism as in the embodiment described later may be used.

Fig. 5 shows the drive motor 2 when changing the output speed.
FIG. 6 is a partial explanatory view of an embodiment in which the support plate 11° 12 is rotated by a driving force from 0 to save the number of driving sources. This embodiment also includes a mechanism for selectively rotating the output shaft 23 in two directions while rotating the motor 20 in only one direction. In other words, the motor 20 is rotated in only one direction, and the scanning means is moved in both the entry direction and the B direction. In addition, in this example, the arrangement of the various means 1 to 6 is the same as the third one.
This is similar to that shown in FIG. In the following figures, members and means having the same functions as those shown in FIGS. 3 and 4 are given the same reference numerals, and explanations thereof will be omitted unless particularly necessary.

In FIG. 5, the input gear l is supported by the frame 15 via a bearing 29, and is fixedly connected to the gear 3° by a connecting pipe 28 passing through the hole 12' of the support plate 12. ing.

The gear 1.3o is integrally rotatably supported by a shaft 31 rotatably supported by the device frame 14.34 via bearings 32, 33. And gear 3o is gear 35
It meshes with the The gear 35 is fixed to the shaft 13 via a loose spring clutch 36 having a model wheel 37.
8. That is, when the control pawl 58 (FIG. 6) engages with the mold wheel 37 and the spring clutch 36 is activated, the gear 35 rotates integrally with the gear 38, and the control pawl 58 engages with the mold wheel 37.
When the spring clutch 36 becomes inactive due to separation from the
The connection between 8 and 35 is broken, and even though 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 controlled by the gears: (5, 30, 1
The signal is further transmitted to the gear 2 via the gear group (group 4 in the case of FIG. 5) corresponding to the selected document image forming magnification among the gear groups 3, 4, 5, and 6, and the output shaft 23 is transmitted to the gear 2. However, the pinion 112 or the output IJ 121 is driven to rotate in the forward rotation direction (direction C) at a speed corresponding to the selected magnification.

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 pinion 112 or pulley 121 will not rotate in the normal rotation direction. Note that 39 is a bearing that rotatably supports the shaft 13 and is fixed to the frame 15.

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 43 provided on a control ring 42. .

437.431.434.441.442.441,4
When the control pawls 59 (FIG. 6), 60 (FIG. 9) are not engaged with any of the gears 38, 44, the spring clutch 41 operates to fixedly connect the gear 40 to the shaft 31, and the gears 38, 46, . The driving force from the motor 20 transmitted through the shaft 47 is transmitted to the shaft 31 to rotate the support plate 11.12 supporting the gear group 3°4.5.6. On the other hand, if the control claws 59 and/or 60 are engaged with any of the above-mentioned vertical claws, the spring clutch 41 is deactivated, the gear 40 idles around the shaft 31, and no rotational force is transmitted to the shaft 31. .

The reference numeral 45 is a tightening type spring having one end locked to the control ring 42 and the other end locked to the shaft 31. (The mechanism for rotating the support plates 11, 1.2 by the rotation of the shaft 31 will be described later.) As shown in FIG. A gear 46 is meshed with the gear 46, and a gear 47 rotatably supported on a shaft 49 fixed to the frame 15.34 is meshed with the gear 46. 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 501C is a slack type spring clutch 5 having a type wheel 55.
A gear 53 is connected via 4. That is, when the control pawl 61 (FIG. 6) engages with the mold wheel 55, the barb clutch 54 is activated, causing the gear 53 to rotate integrally with the gear 50, and the mold wheel 55 is rotated integrally with the gear 50.
When the control pawl 61 is separated from the clutch 54, the spring clutch 54 becomes inactive, and even if the gear 50 is rotating, the gear 53 does not rotate, or can rotate in the opposite direction to the 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 transferred to the shaft 23 through the gears 38, 46, 47L 50, 53, 56.
The shaft 23 and therefore the pinion 112 or pulley 121 rotate in the reverse direction (direction D). on the other hand,
When the spring clutch 54 is inactive and the spring clutch 36 is activated, the shaft 23 rotates in the normal rotation direction at a speed corresponding to the selected original image forming magnification as described above. By alternately switching the spring clutches 36, 54 between the activated and non-activated states in this manner, the document scanning means can be moved in two directions, the A direction and the opposite B direction. However, in this embodiment, the speed of movement in the direction B is one and cannot be changed, but the speed change has a plurality of gear groups on the rotatable support plate as described above between the gears 53 and 56. A mechanism can be provided to switch the speed of the shaft 23 in the reverse direction and thus also the speed of movement of the document scanning means in the B direction. Note that 57 is a bearing that rotatably supports the shaft 23 on the frame 34.

Now, in FIGS. 7, 8, and 9, the support plate 11.1
The rotational drive and its positioning will be explained. This support plate 11.12 is rotatably mounted relative to the shaft 311C1. 62 is a drive plate fixed to the shaft 31 and rotates in one direction (arrow R).

A pin 63 is fixed to this drive plate 62. This bottle 63 passes through an elongated hole 64 provided in the support plate 11 and long in the direction of rotation of the support plate 11.

On the other hand, a bottle 65 is fixedly planted on the support plate 11. A spring 66 is hung between the pins 63 and 65.

Therefore, when the spring clutch 41 is activated and the shaft 31 rotates, the drive plate 62 stretches the spring 66 within the range regulated by the longitudinal end of the elongated hole 64 even when the support plate 11 has stopped rotating. support plate 11 while accumulating elastic force.
It is possible to move relative to .

The support plate 11 is provided with grooves 67, 68, and 69 degrees 70 corresponding to the gear groups 3 and 4 degrees 5,6, 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. Therefore, the groove 67 is connected to the pin 7.
Gear group 3 is engaged when A68 is engaged with pin 71, gear group 4 is when groove 69 is engaged with pin 71i, and running gear group 5 is when groove 70 is engaged with pin 71. Gear groups 6 are each positioned in said 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 a pin 75 provided at a fixed position, and this biases the lever 72 counterclockwise to keep the stopper pin 71 constantly on the support plate 1.
It is elastically biased in one direction.

The driving plate 62 is provided with four protrusions 76, 77, 78° 79 corresponding to the four grooves of the support plate 11. The front portion of each protrusion has a slope 76 in the direction of rotation.
, 77, 78.79'. by this,
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 pin 71 that is engaged with the groove of the support plate 11, the stopper pin 71 moves along the slope. Due to the cam action, it is pushed up from the groove against the elastic force of the spring 74, and can be retracted out of the groove. In this way, the stopped state of the support plates 11, 12 is released and they can rotate in the direction of arrow R about the shaft 31. On the circumference of the control ring 42 of the spring clutch 41, the gear group 3. 4. 5. Claw 441 corresponding to 6
, 442-44s, 444 are provided at intervals in the direction of the rotation axis of the control ring 42.

The shafts 7, 8, 9.10 of said gear group are connected to the support plate 11.
12 at 90 degree intervals, so the claws 441 to 4
44 are also provided on the ring 42 at approximately the same intervals, that is, at approximately 90 degree intervals, but if the installation interval of the shafts 7 to 10 is other than the above-mentioned angle, the installation interval of the claws 441 to 444 should also correspond to that. . The same thing can be said about the grooves 67 to 77 provided on the support plate 11 and 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. ~4
44 abuts against the control stopper 60, the rotation of the control ring 42 is stopped. The rotation of the control ring 42 stops +h
The tightened barb 45 loosens, so the gear 40 and shaft 31
The connection between the drive plate 620 and the drive plate 620 is broken, and the rotation of the drive plate 620 is also stopped.

In addition, when gear group 3 is in the operating position, the pawl 441 is
When gear group 4 is in the operating position, pawl 44. However, when gear group 5 is in the operating position, pawl 44. However, when the gear group 6 is in the operating position, the pawls 444 are in contact with the respective stoppers 60.

As shown in FIG. 9, the control stopper 60 is mounted on a lever 80 rotatably supported on a shaft 81 provided at a fixed position within the device.

The lever 80 is provided with an operation knob 82, 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. can. 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 original image forming magnification.

Incidentally, scales 831 to 834 are carved along the movement path of the knob 82. Scale 83. ~832 are the claws 441 respectively
to 444 (winter melons 441 to 444 correspond to original image forming magnifications of 4 to m4, respectively). (Therefore, they correspond to gear groups 3 to 6, respectively.) Therefore, if the knob 82 is moved from the position of the scale 832 corresponding to the magnification m2 to the position of the scale 83 corresponding to the magnification m, the stopper 60
is claw 44. It is displaced from the position where it was engaged with the claw 44 to a position where it can be engaged with the claw 44.

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.
When the control ring 42 is released from any of the claws and displaced to a position corresponding to the desired document image forming magnification, and the claw 59 (described later) is separated from the claws 431 to 434 of the control ring 42, the spring 45 causes
The driving force from the motor 20 is transmitted to the driving plate 62. At the same time, the control ring 42 rotates. The rotation continues and stopper 6
When one of the control ring claws 441 to 444 corresponding to the selected magnification engages with the gear 40, the spring 45 loosens and the gear 40
The transmission of driving force from the shaft 31 to the shaft 31 is cut off, and the rotation of the driving plate 620 stops. This completes the speed change 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. Then, one of the protrusions provided on the drive plate 62 engages with the pin 71, and as the drive plate 620 rotates, the protrusion kicks the pin 71 out of the groove of the support plate 11. The elongated hole 64 has a length sufficient to enable movement of the drive plate 620 or more, but the pin 63°6
If the spring 66 is arranged only in the space between the drive plate 62 and the support plate 110, and the spring 66 is supported within this space, the elongated hole 64 is naturally unnecessary.

In any case, when the stopper pin 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 pin 71
rides on the circumferential portion 11' 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 is connected to the drive plate 62 via a spring 66 as shown in FIG.
As the rotation continues further, the next groove of the support plate 11 comes to a position where it engages with the pin 71, and the pin 71 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. For this reason, the driving force transmission from the gear 40 to the shaft 31 is not cut off yet, and the driving plate 62 is rotated by the spring 66 against the stopped support plate 11.
Continue rotating while stretching. Therefore, if the stopper 60 is located in the rotation path of the next pawl on the control ring, the pawl will move before the protrusion next to the drive plate 620 kicks out the stopper pin 71 from the groove of the support plate 11. stopper 60
, 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. If the newly selected gear group is one gear group next to the previously selected gear group in the direction opposite to 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 pin 71 falls into the groove 11, the operation of the spring clutch 41 does not stop, and the driving plate 62 continues to rotate, and the next protrusion kicks the pin 71 out of the groove. In this way, the above operation is repeated until the control ring pawl corresponding to the gear group corresponding to the newly selected magnification comes into contact with the stopper 60 and the spring clutch 41 is stopped.

As described above, by positioning the support plate 11, and therefore the gear group, before stopping the operation of the spring clutch 41, even if the accuracy of the stop positioning of the shaft 31 by the spring clutch 41 itself is low, The selected gear group can be accurately and reliably held in the operating position, and the desired document scanning speed can be obtained smoothly and with high precision.

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 change operation described above is not performed.

That is, in FIG. 6, the control ring 42 of the spring clutch 41 has:
Said mold 44. -444, corresponding to each of the gear groups 3-6, respectively, are provided with claws 43. -434 are provided. The pawls 431 to 434 are arranged on the same circumference of the ring 42 so that they follow 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
33, pawl 434 when gear group 6 is in the operating position.
1c.

The claws 59 are adapted to engage with each other.

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 8o. 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 8o is biased to the right by a spring 87. Therefore, the 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 8°, and when the plunger 88 is actuated, the claws 59 and 58 move against the elastic force of the spring 87 to open 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. Then, in a state where 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 4o is transmitted to the shaft 31, If the pawl 59 is engaged with any of the pawls 43□ to 434, the stopper 60 is not engaged with any of the pawls, the main spring clutch 41 does not operate, and the driving force of the gear 40 is transferred to the shaft 31. is not transmitted. Further, when the pawl 58 is retracted from the mold wheel 37, the spring clutch 36 stops operating and the motor 2o
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 the mold wheel 37, the barb clutch 36 is activated, and the shaft 23 starts rotating in the forward direction. Rotate in the direction.

On the other hand, a control pawl 6 that can be engaged with a control type wheel 55 of a spring clutch 54 for transmitting rotational driving force in the reverse direction to the shaft 23
1 is provided on a lever 89 rotatably supported on a shaft 90 provided at a fixed position, and the pawl 61 is attached to a spring 9
1, the ratchet wheel 550 is urged in the direction of leaving the rotation path. And the lever 89 has an electromagnetic plunger 92.
are connected, and when the plunger 92 operates, the claw 6
1 is engaged 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 model wheel 55 by the spring 91, and the operation of the spring clutch 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 forward direction, and the document scanning means is moving in the direction indicated by the arrow, the pawl 59 is controlled. Ring claw 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 the control ring comes off from the pawl, if the pawl 60 is displaced while the scanning means is moving in the input direction, or if the pawl 60 is displaced while moving in the direction of arrow B, the spring clutch 41 is activated and the shaft is 31 begins to rotate, thereby bringing the gear group corresponding to the selected document image forming magnification to the operating position.0 Also, with both plungers 88 and 92 deenergized, a forward rotational driving force is applied to the pick shaft 23. In a state where the reverse rotational driving force is not transmitted and the document scanning means is at the starting position of movement in the inward direction, the pawl 59 does not move either of the pawls 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 incoming direction movement, the speed switching operation of the incoming direction movement is performed.

In FIG. 5, 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 groove 94 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. 5, the variable resistor 96 is interposed between the power source 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. Also, the amount of exposure of the original light image to the photoreceptor is made to be substantially constant.

Further, the above signal can be used, for example, to display the set document image forming magnification, or as a control signal for a servo motor that displaces the zoom lens 103 to a position corresponding to the set 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. Signals corresponding to the gear groups positioned in the actuated position can also be obtained by other means, such as by fixing the couplers in their respective positions and actuating each microswitch or photocoupler with each cam or light shield.

In FIG. 10, the driving force of the cam 93 is applied to the zoom lens 10.
3 to displace the lens 103 to a position corresponding to the selected magnification, and set the lens focal length to a value corresponding to the selected magnification.

In FIG. 1O, 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 pin 126 provided on a focal length adjusting lens element in a zoom lens is engaged with a long hole 125 provided in a protruding piece of this ring 124.

This pin is inserted into a cam hole 127 provided in the lens barrel 123. Therefore, if the ring 124 is rotated, the pin 126
moves relative to the lens barrel 123 in the lens optical axis direction, thereby changing 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 130, 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 t32 is a sliding bearing fixed to the lens stand 128, and the lens stand 128, which is slidably fitted to the rail 131, has a bearing K in a direction intersecting (for example, perpendicular to) the moving direction of the lens stand 128. A long hole 133 is provided, and a long hole 1 with
A pin 136 provided at the tip of a lever 135 rotatably supported by a shaft 134 provided at a fixed position is inserted into the pin 33 . There is a 0-shaped groove 137 at the base of the lever 136.
A lever 13 rotatably supported on a shaft 138 provided in a fixed position is provided in this O-shaped groove 137.
One end portion of 9 is slidably fitted. 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.
Since the U-shaped groove of the lever 135 is pushed at one end of the lever 135, the lever 135 rotates about the shaft 134 as shown by the arrow. The pin 136 provided at the tip of the lever 135 pushes the υ lens stand 128, and the lens stand 128 and therefore the lens 103 move along the rail 131, and in conjunction with this movement, the lens focal length changes. also changes.

The cam groove 94 has the respective gear groups 3, 4, 5.
．． Four positioning parts 94, 94.9 corresponding to 6, respectively.
411.944 (only 94. is shown in the figure). The tip of the lever 139 is connected to the positioning portion 94. When engaged with 94., the lens 103 is at the P1 position. When engaged with 941, it is positioned at the P1 position, when engaged with 941, it is positioned at the P4 position, and when it is engaged with 944, it is positioned at the P4 position, and the focal length of the lens 103 is set at each position where the lens is positioned. will be changed accordingly. Each positioning portion 94 of the cam groove 94. ~944 is the movement direction of the cam (
In this case, they are parallel to the rotation direction), and each has a required length in the cam movement direction. Each part 94. ~
The above-mentioned length of 944 is determined by taking into consideration the positioning error of the shaft 32 by the spring clutch 41, and even if the maximum error occurs than the one corresponding to the selected magnification, the lever 139 will not fit in the cam groove 94. It is preferable that the length is sufficient to prevent displacement from the position corresponding to the selected magnification. (It is desirable to provide the above-mentioned parallel groove portions 94. to 944 in the cam groove 94 in FIG. 5.) In any case, as described above, the operation is linked to the operation of changing the document scanning speed of the document scanning means. Then, using the driving force of the motor 20, the position and focal length of the zoom lens are changed to correspond to the selected magnification.

Alternatively, the cam cylinder 93 may not be used, but a pinio may be provided on the shaft 32, a linearly moving rack may be engaged with the pinio, and the cam plate may be fixed to this rack to drive the lever 139.

Furthermore, in the example shown in FIG. 5, instead of directly fixing the drive plate 62 to the shaft 31, the rotational driving force of the shaft 31 may be transmitted to the drive plate 62 via a gear train. In this case, each first gear of the driving force transmission gear group is always in mesh with the input side gear. Although this is preferable in terms of smooth gear shifting operations, it is not always necessary.

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, 14 indicated by two-dot chain lines in Figure 7
2.143 are a microswitch, a timer, and an electromagnetic plunger, respectively, and the microswitch 141 is connected to the drive plate 6.
2 is acted on by the protrusions 76 to 79 provided corresponding to the gear groups 3 to 6. Therefore, in this case, the protrusions 76 to 79 are switch operating members and are not pin kicking members, so the pin 71 It is provided so that it moves to a position where it does not come into contact with the The microswitch 141 operates at a stage when the spring 66 is slightly stretched after the spring clutch 41 is activated and the drive plate 62 starts rotating in the direction of arrow R.
Among the projections 76 to 79, a projection corresponding to one of the grooves 67 to 70 of the support plate 11 into which the bottle 71 was fitted acts and closes. 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 143 is mechanically connected to the lever 72, and when activated, rotates the lever 72 clockwise against the elastic force of the barb 74, retracting the pin 71 from the groove, thereby supporting the plunger 143. Plate 1] is opened and rotation is started in the same manner as above. Support plate 1
1, the groove in which the pin 71 was engaged moves from the engagement position with the bottle 71, and the timer 142 is deenergized before the next groove comes to the engagement position with the pin 7. , the operation of the plunger 143 is stopped.

As a result, the pin 71 is pressed against the peripheral surface 11 of the support plate 11 by the elastic force of the spring 740. When the groove according to the method described above comes to the engagement position with the pin 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.

Incidentally, instead of the micro switch 1.41, the drive plate 6
arranged so that the optical path between them is blocked by each protrusion of 2,
A photocoupler or the like consisting of a light-emitting element and a light-receiving element facing each other may also be used.

Furthermore, in the above embodiment, the pitch circle of the input gear 1 is inscribed in the circle C1, and the pitch circle of the output gear 2 is circumscribed in the circle C2, but the pitch circle of the output gear 2 is also inscribed in the circle C2. (In this case, the pitch circle of each second gear is circumscribed to the virtual circle C7.) Alternatively, the pitch circle of input gear 1 may also be circumscribed to the circle CI (In this case, the pitch circle of each first gear is circumscribed to the virtual circle C7. The circle is inscribed in the virtual circle C0). An example of the former is shown in FIG. 11, and an example of the latter is shown in FIG. 12. In any case, the support plates 11 and 12 of each gear group are located at the common center X of the circle C1°C2.
Rotates around the axis.

Incidentally, in the above embodiment, an ideal example was shown in which the virtual circles C, C7 and the pitch circles of the first gear and the second gear of the gear group are inscribed or circumscribed, respectively. It is not necessary for the pitch circles of the two gears to be strictly inscribed or circumscribed in each of the virtual circles, and the pitch circle of the input gear is also not required to be strictly inscribed or circumscribed with the virtual circle C3. The pitch circle of the side gear also needs to be strictly circumscribed or inscribed in the virtual circle C7. When each gear group comes to the operating position, the first gear of that gear group becomes the input side gear, and the second gear becomes the output side gear. It suffices if it is in a relationship that engages with the side gear. In other words, the input side gear is located inside, outside, or outside the movement path of the first gear of each gear group when the support plate 11, 12 rotates, and does not prevent the above movement of each first gear. meshes with the first gear of the gear group that has come to the 1 operating position, and - the force output side gear is positioned outside or inside the movement path of the second gear of each gear group when the support plate 11° 12 rotates. Although it does not prevent the movement of each second gear, it is sufficient if the position is such that it meshes with the second gear of the gear group that has come to the operating position. In combination with the arrangement state of each gear as described above and the state in which the gears are strictly internally and externally connected as described above, each first gear and each second gear.

An imaginary circle C in which the pitch circles of the input side gear and the output side gear are concentric,
, C, can be said to be substantially inscribed or circumscribed.

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

The driving force is still transmitted from the drive source 20 to the shaft 13, and the shaft 2
The driving force is transmitted from 3 to the document scanning means by a toothed belt,
Toothed pulley mechanism, chain.

It goes without saying that mechanisms such as sprocket mechanisms and gear trains may also be used.

In addition, the selectable original image forming magnification is 3 or 4 in the 1''J, -t example, but may be 2, or 5 or more.

Further, 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 a corresponding electric signal, and uses the formed electric signal to generate an image. It can also be used as a document scanning device for devices that form images.

As described above, according to the present invention, the document scanning speed of the document scanning means can be changed with a simple configuration, and the document scanning means can still be driven reliably and smoothly to form a high quality document image.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a variable magnification electrophotographic copying machine to which the present invention can be applied, FIG. 3 is an explanatory diagram of main parts of an embodiment of the present invention, and FIG. 4 is an illustration of the A-A arrow in FIG. FIG. 5 is also a partial explanatory view of another embodiment shown by the arrows A-A in FIG. FIG. 10 is an explanatory diagram of an example of a lens drive mechanism, and FIGS. 11 and 12 are explanatory diagrams of main parts of other embodiments of the present invention. ■ is the input IUtl gear, 2 is the output side gear, 3. 4°5.6 is a driving force transmission gear group, 11. 12 is a support plate, 110 is a movable document table, 113, 114, 115
is a movable mirror. Applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) Document scanning means that is moved at a speed corresponding to the selected document image forming magnification, and each of which has a first gear section and a second gear section, and the first gear section and the second gear section. a plurality of drive force transmission means each having a different gear ratio; a rotatable support means supporting the plurality of drive force transmission means at intervals in the direction of rotation; an input side gear that is disposed inside or outside the movement path of each of the first gear sections when the support means is rotated, and receives a driving force from a drive source; Disposed outside or inside the movement path of each of the second gear parts. an output side gear for transmitting a driving force to the document scanning means; and a driving force transmitting means corresponding to the selected speed ratio for rotating the support means when changing the document scanning speed to be connected to the input side gear and the output side. a first gear portion of the selected driving force transmission means, comprising: a switching means for bringing the first gear into an operating position between the gear and the gear;
A document scanning device that transmits a driving force from the input side gear to the output side gear via a second gear section, and moves the document scanning means at a speed corresponding to a selected document image forming magnification. (2) The switching means transmits the driving force from the driving source to the supporting means via the clutch means when changing the document speed, and the supporting means is rotated by the driving force from the driving source. Original scanning device 0 according to claim 1