JPS6091341A - Variable magnification copying machine - Google Patents

Abstract

PURPOSE:To select a combnation of gears having a gear ratio for transmitting a speed corresponding to copy magnification by providing plural gears capable of idling coaxially with a scan driving shaft for an optical system and engaging them with a gear as a driving source, and operating selectively a means which stops the idling of some gear. CONSTITUTION:The driving shaft 46 is driven by a motor through a belt 48 to rotate. Driving gears 70 and 71 fixed thereupon rotate facing idle gears 72 and 73. Disks 76 and 77 which stop the idling of the idle gears 72 and 73 which idle normally through the operation of a one-way clutch are fixed on a main shaft 53 coupled with a pulley for driving the optical system for scanning, and either of couples of pins and cams 78 and 79, and 80 and 81 are engaged selectively to stop the idling; and the rotation of the driving shaft 46 is transmitted to the main shaft 53 to drive the optical system at a speed corresponding to magnification.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an original scanning type magnification copying apparatus. In contrast, the original is scanned by moving the original placing table.

When the copying magnification is changed, the moving speed (original scanning speed) of the above-mentioned driving optical system or movable document table, in other words, the moving body for document scanning, is changed in accordance with the selected magnification. The magnification of the original image formed on the photoreceptor in the direction of movement of the photoreceptor is adapted to the selected magnification. (The magnification of the document image in the direction perpendicular to the photoconductor movement direction is determined by the imaging magnification of the lens that forms the document light image on the photoconductor.) By the way, in the conventional document scanning moving body drive device, Rotating bodies with different rotational speeds are rotated by a gear train from the same drive source, and this rotation is switched by an electromagnetic clutch and transmitted to another rotating body, and this rotational driving force is used to generate a plurality of document scanning moving bodies. scanning speed was obtained. Since such a conventional document scanning movable body drive device uses an electromagnetic clutch, it depends on the environmental physical properties (temperature, humidity, etc.) and surface shape (roughness, ridges, etc.) of the sliding part within the electromagnetic clutch. etc.) fx It
Therefore, the conditions for attaching and disengaging the clutch differ slightly for each document scan. As a result, if the timing of attaching and disengaging the electromagnetic clutch differs for each document scan, in the conventional document scanning speed switching method, the forward movement start time and backward movement start time of the document scanning movable body will differ for each document scan. , the relative relationship between the angular position of the photosensitive drum, which is rotationally driven at a constant speed, and the position of the document scanning moving body changes.

In other words, there are variations in the angular position of the photosensitive drum when the document scanning movable body returns to the forward movement starting point, and as a result, when the document scanning movable body continues to move back and forth, the image on the photosensitive drum may vary. This causes the inconvenience that the formed area deviates from the previous area. Therefore, the above document scanning movable body driving device is not suitable for copying which requires accurate positional relationship of the copied image with respect to the copying material.

In addition, like color copying machines, multiple originals are scanned and each time a different monochrome developed image is transferred to the same copying material, and each transferred image is accurately transferred to avoid color misregistration. Inconveniences also arise when alignment is required. Normally, in order to make the color shift of the image inconspicuous, the positional shift of each transferred image must be within about 0.1 m. However, when using the above document scanning movable body drive device, the image forming area on the photosensitive drum shifts by about 2 to 3 w1t each time the document is scanned, and if transfer is performed in accordance with the rotation period of the photosensitive drum, Similarly, each transferred image has a deviation of about 2 to 3 times. Therefore,
Conventional document scanning movable drive bag using an electromagnetic clutch (
This method is difficult to use in color (multicolor) copying devices because it causes color shift.

SUMMARY OF THE INVENTION The main object of the present invention is to provide a flexible copying apparatus which can prevent the above-mentioned disadvantages and maintain the relative positional relationship between the document scanning movable body and the photoreceptor in a precise predetermined relationship at all times. do.

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

FIG. 1 is a variable magnification color copy image to which the present invention can be applied. The illustrated apparatus can form a color copy image that is the same size as the original, and a color copy image that is % times the size of the original. In the figure, numeral 1 denotes a drum having a photoconductive layer as an electrophotographic photoreceptor, which rotates at a constant speed in the direction of the arrow. In the illustrated example, drum 1
The rotational speed of is the same speed ■ for any copying magnification.

As the photoreceptor 2 rotates, it is first uniformly charged in a charger 3 and then exposed at an exposure station S to a light image of the original O at a selected magnification and with a selected color of light, thereby An electrostatic latent image is formed. This latent image is then developed by one of the developing devices 4, 5, 6.7, which supplies toner of a color corresponding to the selected color light to the photoreceptor. When the latent image is being developed, the other developing units are in a stopped state.

The developing device 4 supplies the yellow toner, the developing device 5 supplies the maze/red toner, the developing device 6 supplies the seven-color toner of sheer color, and the developing device 7 supplies the black toner to the photoreceptor.

The developed image is transferred to a transfer material 8. The transfer material 8 is conveyed from a supply cassette 9 by supply rollers 10.degree. 11, and is supplied to a transfer material support drum 12 which rotates in the direction of arrow T at approximately the same circumferential speed as the photoreceptor 2. The leading end of the transfer material 8 is gripped by a gripper 13 provided on the drum 12. Then, the transfer material 8 is wrapped around this drum 12 and
rotates integrally with. The drum 12 rotates in synchronization with the photoconductor 2, and the transfer is performed so that the leading edge of the toner image of the original formed on the photoconductor 2 and the leading edge of the transfer material 8 reach the transfer station/S at the same time. Transport materials. In the transfer station S, the developed toner image is transferred onto the transfer material by the action of the transfer charger 14. - When forming a color copy image, the transfer material 8 is the release claw 1 after transfer of the one color image.
The toner image is separated from the drum 12 by a conveyor belt 16 and sent to a fixing device 17, where the toner image is transferred to a transfer material.

When forming a multicolor copy image, the drum 12 rotates a plurality of times, and toner images of a plurality of colors, such as two, three, or four colors, are sequentially superimposed and transferred onto a transfer material. Thereafter, the transfer material is separated from the drum 12 by a separation claw 15 and sent to a fixing device 7 by a belt 16, where the superimposed and transferred toner images of a plurality of colors are fixed onto the transfer material 8.

Incidentally, after the transfer, the transfer material 8 is neutralized by a static eliminator 18.

On the other hand, the toner remaining on the surface of the photoreceptor after one transfer is removed by a cleaning device 19, and the charge remaining on the photoreceptor is eliminated by illumination of the lamp 2o.

The original O is placed on a fixed original table 21 such as a glass plate. The original 0 placed on the stand 21 is a first scanning mirror;
The second scanning mirror is moved in the direction of arrow S parallel to the table 2 at a speed ratio of 2:1 for scanning. The positions of the mirrors 23 and 24 shown by solid lines are the forward movement starting points of the respective mirrors, in other words, the Baum positions. and the dashed line position 23'.

24' is at the forward movement end position of mirrors 23 and 24, respectively.
When the mirrors 23, 24 reach positions 23' and 24', respectively, they move back toward their forward movement starting points.

As is clear from the foregoing, the forward movement speed of the mirror 23 in the direction of the arrow S, that is, the scanning speed of the document, is the speed obtained by multiplying the circumferential speed of the photoreceptor 20 by the reciprocal of the selected magnification m, 17 m. , and the forward movement speed of the i-sea 24 in the direction of the arrow S is V/C2m). The reason why the mirror 23 is moved forward at twice the speed of the mirror 24 is to keep the optical path length between the original f11 lenses constant during document scanning.

During scanning of the original, the original or/i is illuminated by a mirror 22 that moves brightly together with the mirror 23. Then, the light from the original is sequentially reflected by mirrors 23 and 24, and is reflected by lens 25.
After exiting the lens 25, the light is reflected by the mirrors 26 and 27, and reaches the exposure station/SI. When copying an original image at the same magnification, the lens 25 and mirrors 26 and 27 are positioned at the positions indicated by the solid lines in the figure, and project an optical image of the original onto the photoreceptor 2. When copying a reduced image, the lens 25 is at the broken line position @25', and the ξ sea 2
6.2 is placed in position 1 at the dashed line positions 26' and 27'. In this way, mirrors 26 and 27 place 1M: i
f is changed to change the total optical path length between the original and the photoreceptor in accordance with the selected magnification, and the position of the lens 25 is changed to change the optical path length between the original and the lens. This is to change the ratio of optical path lengths between photoreceptors in accordance with the selected magnification. In addition, lens 25. As the means for changing the position of the mirrors 26 and 27, the means described in Japanese Patent Application Laid-Open No. 54-41723 can be used, so a detailed explanation will be omitted here.

28, 29, 30, and 31 are filters constituting a color separation optical system, and are fixed to the rotating shaft 32, respectively. By rotating the shaft 32, a desired color filter is inserted into the original image projection optical path. Here, 28 is a filter that transmits blue light, 29 is a filter that transmits green light, and 30 is a filter that transmits red light, respectively, and 31 is an ND filter that does not have wavelength selectivity. A filter 28 is used when projecting a blue light image of the original onto the photoconductor 2, and a filter 29 is used when projecting a green light image of the original.
However, when projecting a red light image, a filter 30 is maintained in the optical path during each scan of the document. The latent image formed by the blue light image is developed by the yellow color developer 4, the latent image formed by the green light image by the magenta color developer 5, and the latent image formed by the red light image by the cyan color developer 6.

A latent image formed by the light image projected through the ND filter 31 is developed by a black developing device 7.

FIG. 2 shows the light source 22 of the device shown in FIG. This shows a part of the device that reciprocates the mirrors 23 and 24, that is, the moving body for document scanning, and FIG. FIG.

In FIG. 2, a mirror 23 and a light source 22 (not shown in FIG. 2) are fixed to a holder 54 at a predetermined angle. A support portion 55 extending in the moving direction of the mirror 23 is integrally provided on the front side of the holder 54, and a leg portion 55a thereof.

55b is loosely fitted into the straight rail 56, and the holding body 54. The mirror 23 is moved along the rail 56.

The rails 56 are parallel to the original table 21 . Holder 54
A roller 57 is rotatably provided at the other end and placed on the upper surface of a linear guide rail 58 parallel to the rail 56. mirror 24
is attached vertically to the holding body 59. A support part 60 is provided integrally with the holder 59 on the front side thereof in parallel with the rail 56, and both legs 60a of the support part.

The holding body 59 is slid along the rail 56 by loosely fitting the hole 60b into the rail 56. A roller 61 is rotatably provided at the other end of the holding body 59 and placed on the upper surface of the rail 58.

One end of the wire 33 is fixed to a mounting portion 62 fixed to the support portion 55 of the holder 54 with a screw 34 or the like. This wire 3
3 is a turn pulley 3 bearing a bearing at a fixed position on the main body of the device.
5, and then guided to the right, and turned downward by a pulley 36, which is rotatably provided at a fixed position on the main body of the device, and after wrapping it around the drum 37 several times,
After guiding it upward and wrapping it around the pulley 36 in the opposite direction to the front, it wraps it around the turn pulley 38 that is rotatably provided at a fixed position on the main body of the device, and then guiding it to the left, and the stopper 3 along the way.
After it is fixed to the mounting part 62 at 9, it is wound around a pulley 40 that is rotatably supported by a shaft fixed to the support part 60, and then guided to the right and fixed to the main body of the apparatus with screws 112. A spring 43 is provided in parallel with the rail 56 between the stacking arm 41 fixed to the support part 60 and the fixing part 42 of the main body of the apparatus to restore the mirror 23, 24 to the forward movement starting position.

A driving force transmission gear 45 is meshed with a drum gear 44 that is integrally fixed to the photoreceptor 2, and a shaft 4 to which this gear 45 is fixed is connected.
Power is applied from an unillustrated drive source (a motor that rotates only in one direction) to the group 747 fixed to the holder 6 through the belt 48. This drive source applies the total number of copies of the set number of copies after the copy switch is turned on. Another gear 70.71 is fixed to the 0 shaft 46 and operates until the copying process is completed.
are gears 72.7 rotatably attached to the shafts 53, respectively.
3, the photoreceptor 2 and the gears 72 and 73 are
Due to the drive source, the mirrors 23 and 24 always rotate in the direction of arrow B both when moving forward and when moving backward. For winding, the drum 37 is fixed to the shaft 53.

The details will be described later, but when scanning a document, the drum 37 is moved to arrow B.
The lamp 22. mirror 23.24
as described above, at a speed corresponding to the selected magnification, respectively.
Move it forward in the direction of arrow S. At this time, the movement of the holding body 59 stretches the spring 43 and stores elastic force.

When the document scanning movable body completes its forward movement, a return force is applied to the holder 59 by the force of the spring 43, and according to the return force, the holder 59 is moved through the 40° wire 33 to the holder 59. Towing. Since the drum 37 is driven in the direction of force indicated by the dotted line arrow A', the winding drum 37 rotates in the direction of arrow B', which is opposite to that described above. During this return movement, as will be described later, the one-way clutch 821-1 connects the gear 75 and the shaft 83, and the rotation in the direction of the drum 370B' is transmitted to the gears 74 and 75 via the shaft 53. A brake device 61 including a sliding friction member fixed to the shaft 83 regulates the backward movement speed of the document scanning moving body from becoming excessive, and a trap is set to reduce the impact when returning to the forward movement starting point. ing.

To explain in detail with reference to FIG. 3, a pulley 47 is fixed to the shaft 46, and receives driving force from a drive source (not shown) via a belt 48. Gears 70 and 71 are fixed to the shaft 46 at appropriate intervals, and the shaft 46 is connected to the drum gear 44 via a gear 45 as shown in FIG. The shaft 53 has
The wire 33 is wrapped around a drum 371 and a disk 76.
．． 77, and the gear 74 is leaking. Gear 72.
73 is rotatably attached to the shaft 53, and the gear 72
The gear 73 is located at a position facing the disc 76 and meshing with the gear 70, and the gear 73 is located facing the disc 77 and meshing with the gear 71. Incidentally, in this embodiment, it is possible to make a copy at the same size and a copy at a quintuple size. Therefore, the rotational speed of the shaft 53 when the shaft 53 is rotationally driven via the gears 71, 73 is M times the rotational speed of the shaft 53 when the shaft 53 is rotationally driven via the gears 70, 72. t, b Like that, the tooth ratio of gear 70.72,
The tooth ratio of gears 71° and 73 is set.

Now, the pin 79 attached to the disc 76 and the cam 78 fixed to the gear 72 are in a positional relationship that allows them to be engaged, and on the other hand,
The bin 81 attached to the disc 77 and the cam 8o or 80' fixed to the gear 73 are also in a positional relationship that allows them to be held together. The cam 80 and the cam 80' are connected to the shaft 53 as shown in FIG.
They are rotationally symmetrical to each other. When the document scanning movable body is at the forward movement starting point, the cam 78 and the bin 79 are in an engaged state, and at this time, the cam 8o or the cam 80' is engaged with the bin 81 (the third The diagram shows cam 80 and bottle 8
1 is engaged) gear 73, cam 8o, and cam 80
'The rotation angle position has been adjusted. When the light source 22 and the mirrors 23 and 24 move forward, the bins and cams of any one of the sets are selectively engaged, and when the light source 22 and the mirrors 23 and 24 move back, they are disengaged from each other. A gear 75 is held on the shaft 83 via a one-way clutch 82, and this gear 75 matches the gear 74 at 1111 points. As described above, the one-way clutch 82 is activated only when the light source 22 and the mirrors 23 and 24 move back, and the gear 75 and shaft 83 can rotate together. Light source 22. When the mirrors 23 and 24 move forward, the clutch 82 does not operate, and the gear 75 is connected to the shaft 83.
The brake 61 does not act because the motor rotates idly.

In the above, gears 70, 72, disk 76° cam 78.
The mechanism including the bin 79 is involved in original scanning during full-size copying (the original scanning speed at this time is called the first scanning speed), and the gear 7
A mechanism including 1, 73, a disk 77° cam 80, 80', and a bin 81 is involved in document scanning during reduction copying (the document scanning speed at this time is called a second scanning speed). Thus, the gear 72 rotates once per cycle of the reciprocating movement of the document scanning movable body, and therefore the gear 73 makes a false rotation with respect to the above-mentioned 11% period.

Next, the operation of this embodiment will be explained. A driving force is transmitted to the pulley 47 via the driving source and the belt 48, which rotates the shaft 46 and further rotates the gears 70, 71. On the other hand, a drum gear 44 is driven by a gear 45 in FIG. 2 fixed to a shaft 46, and the photoreceptor 2 rotates at a constant speed.

Gears 72 and 73 meshing with gears 70 and 71 always rotate in the direction of arrow B at a rotation speed corresponding to their respective tooth ratios. When the light source 22 and the mirror 23 are moved forward at the first scanning speed, the bin 79 and the cam 78 are engaged, and the rotation at the rotational speed determined by the tooth number ratio of the gears 70 and 72 is transmitted to the disk 76, and the shaft 53, the drum 37 rotates at the same rotational angular velocity as above, winding up the wire 33 to achieve a predetermined scanning speed. At this time, the bottle 81 and the cam 80 or 8
The hold of 0' is released when the document scanning moving body starts forward movement,
The gear 73 freely rotates on the shaft 53, and its rotation is controlled by the shaft 53.
It will not be communicated to.

On the other hand, when the light source and gler move back, the bottle 79 and the cam 78
is disengaged, and the restoring force of the light source 22, the mirrors 23, 24, and the spring 43 starts the retaliation, and the wire 33
During unwinding and winding, the drum 37 rotates in the direction of arrow B'.

On the other hand, when the light source 22 and the mirror 23.24't move forward at the second scanning speed, the bin 81 and the cam 80 or the cam 80
' is engaged, and rotation at a rotational speed determined by the tooth number ratio of the gears 71 and 73 is transmitted to the disk 77, and the winding drum 37 is rotated via the shaft 53 at a rotational speed different from the first scanning speed. to achieve the second scanning speed. When the light source and the mirror move back, the cam 80 or 80' and the bin 81 are disengaged, and the light source 4 and the mirror 6.7 return to the document scanning starting point, as in the previous case.

Below, the cam 78 and the bottle 79, or the cam 80 or 80
The structure and operation of the locking device, which is composed of the related components of the bottle 81 and the bottle 81, will be explained in detail with reference to FIGS. 4 to 7. FIG. 4 shows a holding device on the side that is involved in the first scanning speed when the document scanning movable body consisting of the light source 22 and mirrors 23 and 24 is placed at the forward movement starting point and scans the document at the first scanning speed. FIG. 5 is a plan view showing the state of the moving body for scanning the original, and the position of the holding device on the side involved in the @22 scanning speed when scanning the original at the forward movement starting point V and the second scanning speed. A plan view showing the state, FIG. 6, shows the state of the holding device on the side involved in the first scanning speed when the document scanning moving body moves forward at the first scanning speed and reaches the end point of forward movement. FIG. 7 is a plan view showing the state of the holding device on the side that is involved in the first scanning speed when the document scanning movable body moves backward and reaches the forward movement starting point.

In the engagement device involved in the first scanning speed, the cam 78 is fixed to the gear 72 with a screw 200. 7-mu 201
, 202/l11 fixed to I′i disk 76] 203
It is rotatably mounted on the

A bottle 79 is attached to one end of the arm 201, and a spring 204 is disposed between the other end of the arm 201 and the arm 202. The arm 201 is provided with a counterclockwise rotational force by a spring 205. The counterclockwise rotation of the arm 2020 is restricted by a pin 206 fixed to the disk 76. Therefore, as will be described later, the arm 207 is arm 2
01, the counterclockwise rotation of the arm 201 by the spring 205 in the 8 direction is limited within a predetermined angular range. The arm 207 is rotatably supported by a shaft 216 fixed to the disk 76, a spring 208 applies rotational force in the direction of the hour hand, and a bottle 209 is held at one end and a bottle 217 is held at the other end. The 0 arm 210 is rotatably supported by a shaft 211 located at a fixed position on the main body of the copying apparatus, and a spring 212 applies a clockwise rotational force. However, this clockwise rotation is caused by the stopper 21 located at a fixed position on the main body of the copying machine.
It is limited to 3.

A bottle 214 that acts on the arm 202 is installed at one end of the arm 210. The bin 215 is provided at a fixed capacity 1u of the main body of the copying apparatus.

The arm 220 is attached to a shaft 223 at a fixed position on the main body of the copying machine.
The bin 22 is attached to one end so that it can rotate around the center.
1 is implanted, and there is a capacity of 1iK that can act on the bottle 217 of the arm 207. A spring 222 is attached to the other end of the arm 220, and a rotational force in the counterclockwise IT direction is applied to the arm 220.
25, the arm 220 is attached to one end of the arm 219 by a pin 224, and the other end of the arm 219 is attached to a spiral plunger 218 in a fixed position on the copying machine body. is attached to. When plunger 218 is energized, arm 2
19 is pulled toward the plunger 218, and the arm 22
0 is given clockwise rotation.

In the locking device related to the second scanning speed, a cam 80 and a cam 80' having the same shape are placed on the gear 73 and rotationally symmetrically opposed to each other with respect to the shaft 53.
00. It is fixed with screw 300'. Other bins 8
1. The structural relationship between the gear 73 and the disc 77 is the same as that of the locking device involved in the first scanning speed, and the arms and pins are all in the same relative position with respect to the shaft 53. Fourth
The numbers of other arms, cams, bottles, springs, and plungers that correspond to the figures are shown using three-digit numbers, with only the first digit being 3. (See Figure 5) Next, the operation will be explained. First, the light source 22 at a first scanning speed,
The case where the mirrors 23 and 24 are moved forward is set. In the state shown in FIG. 4, the cam 78 and the pin 79 are engaged. In addition, FIG. 5 shows the side that is not involved in the first document scanning speed.
From the same state as in Figure 4, the light source 22, mirrors 23 and 24
Immediately before starting the forward movement, the granger 318 is energized and the arm 320 rotates clockwise. This rotation of the arm 320 causes the pin 321 to act on the pin 317 of the arm 307, and after the arm 307 rotates counterclockwise, the pin 321 acts on the pin 317 of the arm 307.
09 comes off from the arm 301. Then, the arm 301 is rotated counterclockwise by the spring 305, and the pin 81 is disengaged from the cam 80. When the gears 72 and 73 rotate in the direction of the arrow B in the above state, the pin 79 and the cam 78 are engaged, so the disk 76 is rotated in the direction B, and the winding drum 37 is rotated at the first scanning speed. Rotate at the corresponding rotational speed. When the starting arm 202 rotates the arm 210, the arm gear 72, and the disk 76 rotate by a predetermined angle and the document scanning is completed, the arm 207 collides with the pin 215 in the holding device that is involved in the first scanning speed. The pin 209 is then rotated counterclockwise, and the pin 209 is removed from the arm 201. Then, the arm 201 is rotated clockwise by the spring 205, and the arm 201 is rotated clockwise by the spring 205.
9 comes off from the cam 78. Then, the cam 78 continues to rotate in the direction of arrow B, but the winding is caused by the drum 37 and the disk 7.
6 starts rotating in the direction of arrow B' under the action of spring 43.

On the side that is involved in the second scanning speed, the cams 80, 80' and pin 81 are disengaged before the document scanning starts, and at the same time as the disk 76 on the side that is involved in the first scanning speed rotates in the direction of arrow B'. A disk 77 integrally and fixedly connected to the disk 76 by the shaft 53 also rotates in the direction of arrow B'. During this rotation in the B' direction, the pin 209 is pressed against the a' part of the arm 201 by the action of the spring 208, and the pin 309 is pressed against the a' part of the arm 301 by the action of the spring 3080, but the first scanning speed side is When the arm 202 reaches the position shown in FIG. 7, it collides with the pin 214 and is rotated clockwise, which causes the arm 201 to rotate clockwise as well, causing the pin 209 to fall into the notch in the arm 201, and the pin 79 to move toward the cam 78. Immediately thereafter, the cam 7B re-engages with the bin 79. This makes it possible to scan the document again at the first scanning speed. Similarly, in the locking device involved, the pin 309 is connected to the arm 3.
01, the arm 301 is locked so that the pin 81 is located in the rotation path of the cam 80 or the cam 80', and the document can be scanned again.

In this embodiment, the ratio of the first scanning speed to the second scanning speed is 2:3.
Therefore, the ratio of the rotation speeds of gear 72 and gear 73, which are involved in their respective speeds, is also 2:3. One rotation of the gear 72, which is involved in the first scanning speed, is synchronized with one cycle of the reciprocating motion of the document scanning moving body, but during this period, the gear 73, which is involved in the second scanning speed, makes M rotations based on the ratio of the rotation speeds. , gear 72
It rotates more than the number of rotations compared to. When the cam 80 on the gear 73 and the pin 81 are in an engaged state immediately before scanning the original, the gear 73 shifts by a percentage of the rotation after the scanning of the original, and the cam 80' and the pin 81 are engaged. become. Also gear 7
Since it is interlocked with the shaft 46 through the three-way gear 71, and the shaft 46 is interlocked with the photoreceptor 2, the relative relationship between the predetermined rotational position of the photoreceptor 2 and the starting point of the document scanning moving body can be maintained. On the other hand, the cam 78 and the pin 79 that are involved in the first scanning speed are not engaged each time after the document scanning is completed, and the predetermined rotational position of the photosensitive drum 3 and the starting point of the document scanning moving body are always in a one-to-one relationship. Take action.

Therefore, when the document scanning movable body is at the forward movement starting point, it is easy to switch from the first scanning speed to the second scanning speed or vice versa.

To change the document scanning speed, in the above procedure,
This is possible by reversing the operation of the locking device that is involved in the scanning speed and the locking device that is involved in the second speed.

The above example shows the case where the ratio of the first scanning speed to the second scanning speed is 2:3, but if the speed ratio is 1:2, the gear 72
completes one rotation, the document scanning moving body returns to the forward movement starting point, the cam 78 on the gear 72 and the pin 79 on the disc 76 engage again, and the photoreceptor 2 is moved to a predetermined position. When the angular position is reached, the gear 73 rotates twice and the cam 80
0') and the pier 81 engage with each other, only one cam is required to engage with the bin 81. In addition, if the ratio between the first scanning speed and the second scanning speed is more complicated, the gear 72
and 73 are determined corresponding to this speed ratio, and the rotation speed ratio of bin 8
By arranging a plurality of cams for engaging cams 1 and 1 equally circumferentially on the gear 73 in accordance with their speed ratios, the original scanning speed can be changed instantly, and the rotation of the photoreceptor can be maintained at either speed. It is possible to establish a correspondence between the position and the position of the forward movement starting point of the document scanning movable body.

The above-described embodiment is an example of the original scanning speed switching device for equal-size copying and reduced-size copying, but it can also be applied to the case between equal-size copying and enlarged copying or any variable-size copying. In the former case, the gear ratio of gear 70 and gear 72, gear 7 in FIG.
1 and gear 73, and set the number of cams on gear 72 and gear 73 according to the ratio of the two document scanning speeds as described above. Gear 73° cam 80. The mechanism consisting of the bin 81, the disk 77, etc. is the side that is involved in the document scanning speed during full-size copying, that is, the first scanning speed, and the gear 70. Gear 72° cam 78. The mechanism consisting of the bin 79, the disk 76, etc. is controlled at the original scanning speed during enlarged copying, that is, at the second speed.
As for the side that is involved in the scanning speed, by performing the opposite operation for the first scanning speed and the second scanning speed in the description of the above embodiment, it is possible to switch the original scanning speed during equal-expansion copying and enlarged copying. is possible. On the other hand, in the case of arbitrary variable size copying, the gear ratios related to the respective original scanning speeds are set to predetermined values, and the number of cams on the gears 72 and 73 is set according to the ratio of the scanning speeds of both originals. Then, switching between two arbitrary document scanning speeds is also possible.

Note that the discs 76 and 77 do not necessarily have to be disc-shaped, but may have a shape that receives rotational torque from the opposing gear 76 or 77 and transmits it to the shaft 53. Further, the gear 7o and the gear 72 or the gear 71 and the gear 73 do not need to directly mesh with each other, and it is also possible to adjust the rotational speed via a gear for intermediate change.

In the embodiment described above, the return driving force of the document scanning movable body is obtained by the restoring force of the spring 43 during the return movement, but the driving force is obtained from a drive source that drives the photosensitive drum via a clutch mechanism or from another drive source. A method of transmitting the double-acting drive to the Δ shaft 53 may also be used. The operation will be explained below. When the document scanning movable body is moving forward, the clutch is in a disengaged state and does not transmit the backward drive force, and when the document scanning movable body reaches the end point of forward movement and the engagement between the cam 78 and the bin 79 is disengaged (the clutch is disengaged). (Figure 7) The clutch is in the engaged state and applies a rotational force in the backward movement direction to the shaft 53, causing the document scanning moving body to move backward. Immediately before the end of the backward motion, the positional relationship of the locking devices is as shown in FIG. The gear 72 rotates in the direction B and the engagement devices on the disk 76 rotate in the B' direction until the document scanning moving body reaches the end point of the backward movement, and the clutch mechanism is disengaged at the position where the forward movement starts, and the document scanning starts. The return movement of the moving body and the disc 76 is stopped. At this time, the bottle 79 waits until the cam 78 rotating in the B direction approaches and joins. When cam 78 engages bin 79, scanning of the next document is resumed.

In the document scanning speed switching device having the above-mentioned holding device, the positional relationship in which the bin and the cam engage is determined mechanically, so the moment when the bin and the cam engage, that is, the light source 2
The angular position of the photoreceptor at the time when the light source 22 and the mirrors 23 and 24 start moving forward is constant, and when the light source 22 and the mirrors 23 and 24 are repeatedly moved back and forth, an image is formed at the selected magnification. The areas on the photoreceptor 2 always match.

FIG. 8 is an expanded embodiment of the nine device arrangement shown in FIG. The shaft 46 to which the driving force is transmitted from the driving source has three or more types of gears 90 a with different numbers of teeth spaced at appropriate intervals.
90b, 90c, -- are fixed, and gears 91a mesh with these, respectively.

91b, 91c, . . . are rotatably attached to the shaft 53. Gears 91a, 91b, 91c.

... have forces A 92 a and 92 b, respectively.
, 92c.

... is fixed, and a disk 93a on the side opposite thereto.

93 b, 93 C, ... each have pi/94
a.

94b, 94C, . . . are supported. The opposing pins and cams are in a positional relationship that allows them to be secured, and during the forward movement of the stx document scan, one of the pins and the cam selectively engages, and the shaft 53 and the winding drum 37 are rotated at a predetermined rotational speed. The wire 33 is rotated to wind it up, and the document scanning moving body is moved forward at a speed corresponding to the desired copying magnification. When returning,
All the pins and cams are released, and the document scanning moving body moves backward due to the restoring force of the spring 43, and the wire 33 is rewound, and the winding is performed by moving the drum 37 in a direction different from that when moving forward. The disks 93a, 93 are rotated through the shaft 53.
b, 93C, . . . are returned to the original scanning starting point. Converting the speed during the forward movement of document scanning can be achieved by engaging another pin and a cam, and a gear 90a is fixed to the shaft 46.

90b, 90c, ... and the shaft 53 that meshes with them
Upper rotatable (D gear 91 a, 9 l b, 9
1c.

. . . Further, discs 93 a , 93 b , 93 c , facing the gears 91 a , 91 b , 91 c , . . .
River and gear 91 a, 9 l b, 91 c
, - and disk 93a.

Force A that engages each of 93b, 93c, ...
92a, 92b, 92c, --- and via 94m.

By further increasing the number of combinations of 94b, 94c, . . . , an apparatus capable of converting document scanning speeds into three or more types becomes possible. Therefore, with this single device, it is possible to switch the document scanning speed according to three or more types of copying magnifications, such as copying, same-size copying, reduced copying, and enlarged copying. Note that the double-acting speed control mechanism is omitted in FIG.

In addition, gears 90a, 90b, 90c and gear 91a,
It is not necessary that the gear ratios of 9lb and 91C are all different, but by providing multiple sets with the same gear ratio and changing the position of each cam 92, it is possible to make the same gear ratio as shown in Fig. 5. It is also possible to avoid arranging a plurality of cams on the gear, and to switch the original scanning speed and the rotational position of the photosensitive drum by switching the gear h series to be used. For example, the gear 90a and the gear 91a are gears that are related to the same-size copying, that is, the first scanning speed,
Gear ratio of gear 90b and gear 91b and gears 90c and 91
If the gear ratio of the cam 92b and the cam 92C is the same and the ratio of the first scanning speed and the second scanning speed is 2:3 as both are gear systems involved in the second scanning speed, then the fixed position of the cam 92b and the cam 92C is They are set at 180 degrees different positions on gear 91b or gear 91c, respectively. The gear system involved in the @1 scanning speed is the same as in the previous embodiment; one rotation of the gear 91a is synchronized with one cycle of the reciprocating movement of the document scanning moving body, and the cam 92a and pin 94a are engaged each time the document scanning is completed. become possible.

On the other hand, in the gear system involved in the second scanning speed, when the cam 92b and pin 94b are in the engaged state immediately before scanning the document,
After scanning the original, the gears 92b and 92C rotate 3A, and the cam 92C and pin 94c can now engage. Therefore, the original scanning switching instruction operation can be performed immediately, and the relative positional relationship between the rotational positions of the original scanning moving body and the photoreceptor can always be kept constant. This is because when a complicated magnification ratio is set during variable magnification copying, the number of cams disposed on the gear 73 may increase if the embodiment shown in FIG. This method is particularly effective when it is difficult to arrange a large number of cams.

FIG. 9 shows another embodiment of the present invention, in which pins 100, 101 are supported on both sides of a drum 37, cams 104, 105 are provided on opposing gears 102, 103, and gears 106 and 105 are provided, respectively. It is interlocked with a shaft 46 connected to a drive source via a gear 107. When the document scanning movable body moves forward, the cam 104 and the pin lOO or the cam bin are disengaged, and the movable body moves backward by a second driving source such as the elastic force of a spring. In FIG. 9, when the cam 104 engages with the 0-pi/100, which does not include a backward-speed control mechanism, the forward speed of the moving body is determined by the number of teeth of the gear 102 and the gear 106, The case in which the pin 101 and the cam 105 engage is determined by the number of teeth of the gears 103 and 107, and the forward speed of the moving body can be changed by selecting the pin and cam to engage. In this embodiment, it is possible to downsize the entire device.

In the apparatus shown in FIG. 1, the image formed on the photoreceptor is directly transferred from the photoreceptor to a transfer material such as paper that will become the final copy, but before the image is transferred to the transfer material, Toner images of specific colors are sequentially superimposed and transferred from a photoreceptor to an intermediate transfer medium such as a belt, and the superimposed and transferred toner images are transferred from this intermediate transfer medium to a transfer material such as paper that becomes the final copy. It is also possible to perform batch transfer.

Further, the present invention is particularly useful for multicolor copying machines in that it can prevent color shift and obtain good images, but it can also be applied to monochrome copying machines.

Further, the present invention can be applied to a variable magnification copying machine that scans a document by moving the document table with respect to a fixed YT system, and can also be applied to driving the document table.

As explained above, the copying apparatus according to the present invention is such that the document scanning speed is switched by the alignment device.
Since the positional relationship held by the holding device is determined mechanically, the angular position of the photoreceptor at the starting point of forward movement of the document scanning moving body is constant. Therefore, when the document scanning movable body is continuously moved forward, the areas on the photoreceptor where images of the selected magnification are formed always match, which is the problem that conventional document scanning speed switching devices using electromagnetic clutches have. Problems can be resolved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing a copying apparatus to which the present invention can be applied, FIG. 2 is a perspective view of a reciprocating drive device for a moving body for document scanning, and FIG. 3 is a document scanning apparatus according to an embodiment of the present invention. FIG. 4 is a front view of the main parts of the driving device of the document scanning moving body, and FIG. The figure shows the document scanning moving body at the forward movement starting point, a plan view showing the state of the holding device that is involved in the second speed of document scanning, and the sixth document scanning moving body at the first speed of document scanning. FIG. 7 is a plan view showing the state of the holding device (the side involved in the first speed of the document scanning speed) when the document scanning moving body moves backward and reaches the forward end point. A plan view showing the state of the holding device (the side involved in the first speed of the document scanning speed) when reaching the forward movement starting point, FIGS. 8 and 9 are other embodiments of the document scanning movable body drive device FIG. 22, 23, 24... document scanning moving body, 37.
...first rotating body, 70, 71... second rotating body, 72, 73... third rotating body, 78, 79, 80, 81... engaging means, 43...
a second driving source;

Claims (1)

[Scope of Claims] A movable photoreceptor, an imaging means for forming an image of an original on the movable photoreceptor at a selected magnification, and an original scanning device for scanning the original 11K at a speed corresponding to the selected magnification. A variable magnification copying apparatus comprising: a first rotating body for outputting a driving force to the original scanning moving body; a driving source; and a drive source driven by the driving source. a second rotating body that is rotationally driven in the direction; and a plurality of rotating bodies that are interlocked with the second rotating body, are rotatable with respect to the first rotating body, and are provided independently of each other, and each rotate at a different speed. a third rotating body; provided between each of the third rotating bodies and the first rotating body, the third rotating body is selectively connected to the first rotating body; coupled to the driving force of the driving source,
via the second rotating body and the third rotating body, the first
rotating a rotary body to cause the document scanning movable body to move forward, and when the forward movement is completed, a locking means for releasing the connection; A variable magnification copying apparatus comprising: a drive means for moving the document scanning movable body backward after the connection is released.