JPS6027972B2 - Copy machine variable magnification optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable magnification optical device for a copying machine capable of variable magnification copying.

The optical device of a copying machine having a variable magnification function is generally configured by a combination of the following exposure methods m to {4' and variable magnification mechanisms (a}, 'b}.

That is, the exposure method is {1} document platen scanning slit exposure;
[2' Mirror scanning slit exposure, '3' Lens scanning slit exposure, '4' Full exposure, and in the variable magnification mechanism, the {a} mirror is moved to change the optical path length between the original and the imaging surface, and the magnification is reduced to 4. {b) One that moves the lens unit to a predetermined position in order to correct the image formation position, {b) Changes the focal length of the lens unit without changing the optical path length between the original and the image formation surface, and corrects the image formation position during reduction In order to do this, there is a method to move the unit to a predetermined position, and it is a combination of the above. In these combinations, (1) platen scanning slit exposure and (2) mirror scanning slit exposure require a large scanning distance and are unsuitable for high speed, and (2) full-scale exposure has drawbacks such as the overall size of the machine. In addition, in the variable magnification mechanism (b) that changes the focal length of the lens unit, the mechanism of the lens unit becomes complicated, making adjustment difficult and expensive.Therefore, the remaining combination, namely the exposure An optical device is used in a copying machine, which employs a leg lens scanning slit exposure system and a magnification changing mechanism in which the optical path length is changed by moving a mirror (a).

One of the known optical devices of this type is such that the entire lens unit moving mechanism for moving the lens unit to a predetermined variable magnification position also performs movement for scanning an original.

That is, a variable power motor is installed in a fixed part separately from the main motor,
The rotational force of this variable magnification motor is transmitted to the lens unit moving mechanism using a flexible intermediate member so that the moving mechanism can be moved to a predetermined variable magnification device. It uses wires or cams and bars to enable scanning movement by the main motor, and in order to determine the optical path during reduction, a detector is installed directly at each point where the optical elements such as the lens unit and mirror unit should be stopped. They are being reassigned. However, in the above-mentioned apparatus, since the entire lens moving mechanism section scans, the scanning weight becomes large, and therefore a large driving force is required for movement, and the scanning speed cannot be increased.

In addition, since scanning is performed while the lens unit moving mechanism and the variable magnification motor are connected, the curved state of the flexible intermediate member that connects them changes with the scanning movement of the lens unit moving mechanism, and the lens unit It is difficult to perform stable scanning because the force applied to the object is unstable. Such a flexible intermediate member has a problem in terms of durability because one side of the flexible intermediate member remains stationary and the other side swings, and also requires a mechanism for correcting the curved state. Furthermore, in the above device, it is necessary to connect the movement mechanism of the optical element other than the Shinnzunit with a drive source and a clutch, etc., and adjustment is difficult because a detector is used for each stop position of the optical element. There is a drawback. As described above, conventional optical remounting has a large number of parts, is complex in construction, and is therefore expensive. SUMMARY OF THE INVENTION An object of the present invention is to provide a variable magnification optical device that can be used in a variable magnification high speed copying machine, which has a light scanning weight and can provide a stable scanning speed.

Another object of the present invention is to enable lens scanning drive and control with easy speed changes when changing magnification.

The present invention will be explained below with reference to the illustrated embodiments.

FIG. 1 schematically shows a copying machine capable of double-sided copying and variable-magnification copying, and has a variable optical section IA on the left side of the figure and a copying section IB on the right side. In the variable magnification optical section IA, a document loading plate 2 is fixed to the copying machine housing 1 at the upper part thereof, and illumination devices 3 and 3' are arranged below the document loading plate 2 on both sides of the document loading table 2, respectively. .

Both illumination devices 3, 3' include light sources 4, 4', swinging mirrors 5, 5' that reflect the light from the light sources to the original teaching layer plate 2,
Reflector shades 6, 6' are used to direct the light from the light source to the swinging mirror, and the swinging mirrors 5, 5' are rotated back and forth within a predetermined angular range, so that the light on the document platen plate 2 is It is comprised of a drive device (not shown) and a control device (not shown) for illuminating and scanning a document (not shown). The alignment and rotational movement of the swinging mirrors 5 and 5' allows the irradiated light from the illumination devices 3 and 3' to coincide with each other on the manuscript board 2, and to maintain that state, so that the irradiated light does not overlap the manuscript board 2. It is controlled to run on the layered plate 2 at a constant speed. By doing so, the document surface is illuminated and scanned without the amount of light decreasing near both sides of the document surface. A lens moving device 8 including a lens 7 is disposed in the middle of the variable magnification optical section. This lens moving device 8 will be explained in detail later, but
A guide rod 12 that guides the lens 7 in the scanning direction (horizontal direction in FIG. 1) parallel to the document surface as shown by the arrow x in FIG.
A rod carrier (first carriage) 10 including a rod carrier (first carriage) 10, and a support guide that allows the first carriage 10 to be movable in a direction perpendicular to the document surface (vertical direction 8 in FIG. 1) as shown by arrow Z in FIG. and a carrier bracket (second carriage) 20 that can move in the Y direction as a whole, that is, in a direction parallel to the document surface and perpendicular to the scanning direction (perpendicular to the plane of the paper in FIG. 1). When making a reduced copy, the first carriage 10 is guided by the second carriage 2 and lowered to a position a certain distance away from the original teaching plate 2, so that the lens 7 moves, for example, to the position indicated by the chain line in FIG. Take. Further, during this downward movement, the second carriage 20 moves in a direction perpendicular to the paper plane of FIG. 1, so that the position of the lens 7 is slightly shifted. The reason will be explained later. A mirror unit 9 having two mirrors 66 and 67 oriented in a V-shape with respect to each other is arranged at the lower part of the metamorphosis optical section IA, and the position is as shown by the chain line in FIG. 1 during reduction copying. Change.

This is to change only the optical path length while keeping the angle of incidence on the photosensitive drum 100 in the copying section IB unchanged. Therefore, the direction P in which the mihuunit 9 moves is a direction that is shifted by an arbitrary angle with respect to the optical axis of the lens 7. The image of the document irradiated by the illumination devices 3, 3' and scanned by the swinging mirrors 5, 5' and the lens 7 passes through the mirror unit 9, and then passes through the photoreceptor drum 1.
It is projected and imaged onto 00. Prior to this, the surface of the photoreceptor drum 100 is uniformly charged by a charging device 101, so that a static exposure latent image of the original is formed on the photoreceptor drum 100. This latent image is then visualized by the developing device 102. The developed toner image on the photoreceptor drum 100 is superimposed on the transfer paper fed at an appropriate timing from the paper feeder 103 or 103', and is transferred onto the transfer paper by passing through the transfer device 104. transcribed.
After passing through the transfer device 104, the transfer paper with the toner image transferred thereto is separated from the photosensitive drum 100 by a separation conveyance device 105, and then sent to a fixing device 106. The transfer paper on which the toner image has been fixed by the fixing device 106 is transferred to the 9E paper tray 10 according to the switching position of the tray selection guide 107.
8 Moshi< is sent to the double-sided copying tray 109. The tray selection guide 107 is controlled by a control drive device (not shown) depending on the copy mode selected by the copy mode specifying means (not shown), that is, single-sided copying or double-sided copying.
It is designed to switch to the tray 108 or 109 side. The transfer paper on the double-sided copying tray 109 is sent out again from the double-sided paper feeder 11 to the common conveyance path with the above-mentioned paper feeders 103 and 103', and after undergoing the above-described copying operation, is sent to the paper output tray 108. It will be done. After the transfer, the photosensitive drum 100' is neutralized and cleaned by a cleaning device 111. The reduction ratio of the reduction copy of the above-mentioned copying machine cannot be selected steplessly, but one of several reduction ratios prepared in advance can be selectively selected by a variable magnification mode means (not shown). is now specified.

When the reduction ratio is specified by this variable magnification mode means, the first
The carriage 10 therefore moves the lens 7 to a position away from the document stacking plate 2 by a corresponding distance in the Z direction, and the mirror unit 9 moves the photosensitive drum 100 in the P direction tilted by an arbitrary angle with respect to the optical axis of the lens. and fixed to maintain optical relationship. Furthermore, the optical axis of the second carriage 20 and hence the lens 7 is slightly shifted in the Y direction.
The reason is that if the lens 7 is simply moved downward without shifting the position of the optical axis of the lens 7,
As shown in Fig. 2, the image formation position on the original surface 2a is as shown in 2b, and the image formation point on one edge A of the original is shifted by an amount △ from the image formation point B at the same magnification, and becomes B'. It is. Therefore, in order to ensure ease of handling of originals for the copying machine user, some copying machines are designed to align the original with the negative edge of the original stack plate 2, that is, with A in FIG. It is important to correct the positional deviation of the copy image on the transfer paper caused by the deviation of this Δ amount. To make this correction, it is necessary to shift the position of the transfer paper relative to the toner image on the photosensitive drum 100, or to shift the position of the lens 7 in the Y direction in FIG. In the former case, possible means include sliding the transfer paper while it is being conveyed to the photoreceptor drum 100' or changing the stock position of the transfer paper. However, configuring the copying machine in this manner is not appropriate as it increases the risk of problems such as paper jams. Therefore, in the optical device of this embodiment, the latter correction method of shifting the position of the lens 7 is adopted. However, this amount of correction, that is, the amount of shift of the lens optical axis, does not necessarily have to make the image forming position B' at the time of reduction match the image forming position B' at the same magnification, but it is necessary to reduce the deviation △ between B and B by an arbitrary amount. By correction, it is also possible to create a binding margin with a width sufficient to increase a desired width, for example, punch holes, in the reduced copy. FIG. 3 shows details of the lens moving device 8. As shown in FIG. In FIG. 3, a first carriage 1 is cantilevered by a vertical support rod 21 provided on a second carriage 20 so as to be movable up and down.

In order to prevent the first carriage 10 from rotating around the vertical support rod 21, the second carriage 20 is provided with an auxiliary rod 22 parallel to the vertical support rod 21, while the first carriage This auxiliary rod 22
Hatanai contacting from both sides in the diametrical direction. 15, 15' (FIG. 8) are provided.

This assembly of both first and second carriages is located between the two side plates 41, 42 of the optical section IA. Between the side plates 41 and 42 of the metamorphic optical section IA, a guide rod 43 passes through the upper part and a guide rod 44 passes through the lower part in the above-mentioned Y direction.
It is fixed at 2.

The second carriage 20 is slidably supported on this upper guide rod 43 by means of its two ears 23, 23'. In order to prevent rotation of the assembly about the guide rod 43, the second carriage 20' is provided with guide rollers 24 that are in contact with the lower guide rod 44 and roll on this rod. Thereby, the vertical support rod 21 of the second carriage is held vertically, ie in the above-mentioned Z direction. The first carriage is cantilever-supported and guided by the vertical support rod 21 of the second carriage 20 and extends from the rod 21.
The carriage 10 has a generally rectangular closure 11 on its side near the side plate 42 .

The carriage portion 10a forming the closing opening 11 has two parallel guide rods 1 extending in the X direction inside the closing opening 11.
2, 12' are fixed. This guide rod 12,1
A lens holder 13 to which a lens 7 is attached is slidably supported at 2'. That is, the guide rod 12 passes through one side of the lens holder 3, and the other side of the lens holder 13 is supported by guide rollers 14, 14' that run oppositely to the guide rod 12' from both sides in the diametrical direction. A so-called linear motor that functions as a scanner motor 80 is provided in a portion 10a of the first carriage 10 on the side plate 41 side, so that the lens holder 3 and hence the lens 7 can perform scanning motion in the X direction. There is. In FIG. 3, the second carriage 20 has a vertically long opening 25 in a portion where the vertical support rod 21 is present. A stop pin 16 fixed to the boss portion 10c of the first carriage 10 protrudes beyond this opening 25, and the second carriage 20
The stop lever 27 is adapted to engage with the gourd portions 27a and 27b of the stop lever 27, which is rotatably suspended from the back surface 20a of the stop lever 27, that is, the surface 20a on the side where the first carriage is not present. That is, the pin 16 of the first carriage engages with the uppermost gourd part 27a during full-size copying, and engages with the lower gourd part 27b at the first reduced copying position, and is held at that position by its own weight. There is. A stopper 28 whose height can be adjusted is provided at the bottom of the second carriage 20, and the boss portion 10c of the first carriage comes into contact with this stopper 28 at the second reduced copying position and comes to rest. Stop lever 2
7 is always rotated in the direction opposite to the pin 16 by the spring 32, but can be rotated in the direction away from the pin 16 by the solenoid 301 via the arm 31. Reference numeral 29 is a limiter that determines the range of movement of the lever 27.

On the side of the side plate 41 of the second carriage 20, another vertically long entrance or notch 33 is provided, and through this notch 33, a carriage slide roller 17 fixed to the first carriage 1 protrudes. . Further, a cam plate 45 for a carriage slide is attached to the side plate 41 at a position where it can be opposed to the rollers 17 so as to be adjustable later. and the second
A sliding spring 34 is provided between the carriage 20 and the side plate 41, and the roller 17 is constantly pressed against the cam plate 45 by the force of this spring. Therefore, when the first carriage 10 moves in the vertical direction along the vertical support rod 21 of the second carriage, the rollers 17 slide along the cam plate 45, which causes the second carriage 20 and therefore the lens 7 of the first carriage to Slide in the direction. The roller 17 is on the cam surface 45a at the same-size copying position, on the cam surface 45b at the first reduced copying position, and on the second cam surface 45a.
At the reduction copying position, it comes on the cam surface 45c and corrects the imaging position of the lens during reduction as explained in FIG. As mentioned above, when changing the copying magnification, the guide rod 12 for scanning,
12' is moved parallel to the document surface to change the scanning position of the lens.

Therefore, only the minimum number of objects, such as the lens 7 and lens holder 13, need to be moved for scanning, and it is possible to reduce the weight of the moving object and increase the scanning speed.
The vertical movement of the first carriage 10 relative to the second carriage 20' is controlled by a wire suspended in a U-shape from pulleys 35, 18, and 36, one end of which is fixed to the side plate 41 with a screw 46, and the other end is connected to an idle pulley. This is done by a drive wire 39 fixed to a drive pulley 38 via a wire 37.

The pulley 18 is a working pulley attached to the boss portion 10c of the first carriage and located on the back side 20a of the second carriage through the closing opening 25, that is, a pulley that moves up and down together with the first carriage 10. The pulleys 35 and 36 are fixed pulleys provided on both sides of the upper part of the opening 25 on the back surface 20a of the second carriage. The drive pulley 38 is connected to the side plate 42
The idler pulley 37 therefore functions to change the direction of the drive wire 39. The drive pulley 38 is rotationally driven by a variable power motor 4 attached to the side plate 42 via an L-shaped plate 46'. That is, as can be clearly seen from FIG.
worm gear 4 fixed on the shaft of the same gear.
8. Rotate the worm wheel 49 to drive the drive pulley 38. This worm mechanism prevents the first carriage 20 from freely falling even if the power is momentarily turned off or other situations occur. FIG. 4 shows the principle of separating the vertical movement and lateral movement of the first carriage using the wire and pulley.

Now, with the drive pulley 38 stationary, the second key
Try moving the carriage 20 along the guide rod 43. At this time, if the relative positional relationship of the pulleys 35, 18, and 36 does not change, even if the whole moves from the solid line position to the broken line position in FIG. 4, the height position of the moving pulley 18 in the Z direction or the horizontal wire There is no change in the distance d from 39. In other words,
The distance d is related only to the amount of winding of the drive pulley 38. Therefore, the vertical movement and lateral movement of the first carriage 10 can be controlled separately and independently. Therefore, when performing vertical movement or lateral movement, there is no need to re-correct the other position, making the movement mechanism simple and easy to control.
In FIG. 5, an inverted V-shaped lever 50 that is rotatable about a shaft 51 is provided on the back surface 20a of the second carriage.
It is located at a higher position than the wire 39 stretched between the wire 5 and the wire 39.

A pulley 52 is attached to one arm of the lever 50.
The pulley rides on wire 39. The other arm of the lever 50 is subjected to a rotational behavior by a spring 54 in the direction in which the pulley 52 pushes down the wire 39. The lower end 55 of the other arm of the lever 50 functions as a feeler portion capable of shielding light between the light emitting and receiving elements of the variable magnification sensor 56. That is, the lever 5 is a feeler and tension lever, and the first carriage 10 stops at a predetermined position and the wire 3
9 is loosened, the lever 50 is rotated by the spring 54 from the dotted line position to the solid line position in FIG. ing. In FIG. 6, the side plate 42
The drive pulley 3 is rotated by a variable power motor 40.
A drive sprocket 57 is fixed to 8, and sprockets 58 and 59 are provided below this drive sprocket 57, and these sprockets 57, 58,
A chain 60 is wound around the chain 59.

A fan-shaped feeler 61 is attached to the sprocket 58, and around the feeler 61 are two variable magnification sensors 62 and 63 consisting of photointervals that detect the feeler and turn it on. , are placed apart from each other. Sprocket 59 is attached to a rod 65' having a millilift cam 64. Third
In the figures and FIG. 6, two mirrors 66 and 67 of the mirror unit 9 are fixed to a mirror bracket 68 in a V-shape.

This mirror bracket 68 needs to move diagonally up and down along the P direction in FIG. For this purpose, side plates 41,4
2, four mirror guides 69 (the side plate 41 side is not shown) are attached along the P direction in FIG. 1, that is, along a line inclined at an arbitrary angle with respect to the Z direction. be. These mirror guides 69 have guide grooves 70 inside. The mirror bracket 69 is provided with a guide roller (not shown) that protrudes through a hole (not shown) in the side plate, and this guide roller is inserted into the guide groove 70 of the mirror guide.
I am able to drink alcohol inside my body. Therefore, the mirror bracket 68 is slidably guided at a predetermined angle by the guide rollers and the guide groove 70, and the mirror bracket 68 is slidably guided by the guide rollers and the guide groove 70.
It is held by its own weight on the mirror lift cam 64 by the mirror IJ foot roller 65 fixed to 8. The mirror lift cam 64 moves with the drive pulley IJ 38 via the chain 60, rotates in accordance with the amount of vertical movement of the first carriage 10, and moves the mirror bracket 68 to a predetermined position. Next, the operation when changing the actual copy magnification will be explained with reference to FIGS. 5 to 7.

When the main switch (not shown) is turned on, the variable magnification position of the first carriage 10 is detected by the variable magnification sensors 56, 62, and 63. If the magnification change position of the first carriage 10 is not at the same magnification position as shown in FIG. (not shown), the first carriage 10 is returned to the same magnification position.
0 is assumed to be at the same magnification position.

Now, when the reduction ratio is designated by the magnification designation means (not shown), the variable power motor 40 temporarily rotates in the direction to wind up the drive wire 39 (hereinafter referred to as "normal rotation").

As a result, the lever 50 is placed in the dotted line position shown in FIG. 5, and the abnormality sensor 56 is turned off. The first carriage rises one level, and the stop pin 16 of the first carriage separates from the outer part 27a of the stop lever 27 of the second carriage. On the other hand, the fan-shaped feeder is connected to the variable power motor via a chain 60.
The roller 61 also rotates in the direction of the arrow E in FIG. The fan-shaped feeler 61 is located at the position shown in FIG. 6 at the same magnification, and the variable magnification sensor 6
2 and the feeler tip 61A is very small.
Therefore, the variable power sensor 62 is turned on as soon as the pin 16 is separated from the claw portion 27a of the stop lever by one or two bars. When the change sensor 62 is turned on, the solenoid 30 is turned on, the stop lever 27 is rotated counterclockwise in FIG. 5 via the arm 31, and at the same time, the variable power motor 40 is reversed.

That is, the four-way motor rotates in a direction that loosens the wire 39, and the working pulley 18 and therefore the first carriage 10 descend. The instantaneous position of the descending first carriage 10 depends on the amount of rotation of the drive pulley 38, that is, the feeler 61.
It is detected by a combination of the on/off states of the variable magnification sensors 62 and 63 depending on the position of the magnification sensor 62, 63.

For example, when both magnification sensors 62 and 63 are OFF, it is the timing to turn off the solenoid 30 when you want to move the first carriage 10 to the first reduction position, and when the magnification sensor 63 is OFF and only 62 is ○N. When the second
It is determined that it is the timing to turn off the solenoid 30 regarding the reduction position hawk. The rotation of the feeler 61 and the rotation amount of the drive pulley 38, that is, the position of the first carriage 10, are detected by the variable magnification sensors 62 and 63, and the specified stripe 4.
The solenoid 30 turns O at each timing depending on the rate.
It will be FF.

Therefore, the stop lever 27 returns to its original position due to the balance between the spring 32 and the stop lever itself. The first carriage 10 continues to descend, and its stop pin 16 supports the lower claw portion 27b of the stop lever 27 that has returned, or
Or, it will hit the stopper 28 of the lowest layer.

However, the variable magnification motor continues to reverse rotation, and for this reason,
The drive wire 39 begins to loosen, and the V-shaped lever 50 is rotated counterclockwise in FIG. 5 by the spring 54, turning on the variable power sensor 56. The variable power motor 40 is turned off at this point. To do this, the first carriage 1
By loosening the drive wire 39 even after 0 has reached the predetermined contracted position, the first carriage 10 can be stably set at the predetermined position by its own weight, and the influence of overrun etc. on the predetermined position due to acceleration during movement can be avoided. This is to eliminate it. Also, the cam surface 45 of the cam 45 for the first carriage slide
A to 45c are formed as flat portions to eliminate the above-mentioned error. As the first carriage 10 moves from the isometric position to the first or second contraction position 4, the sliding roller 1
7 also transitions from the cam surface 45a of the sliding cam plate 45 to 45b or 45c.

Therefore, both the first and second carriages 10, 20 are connected to the spring 34.
5 to the left in FIG. 5, and the image forming position of the lens 7 described in FIG. 2 is corrected. Further, the mirror lift cam 64 is rotated by the chain 6 in accordance with the amount of descent of the first carriage 10, and moves the mirror placket 68 to a predetermined contracted position. The mirror lift cam 64 also has a flat cam surface at a predetermined reduced position to eliminate overrun errors. In other words, the amount of overrun is preset in the mirror lift cam 64 in anticipation of the amount of overrun. The change from the first reduced position to the second reduced position is also the same as above, and the variable magnification motor 40 is
After raising the stop pin 16 slightly to separate it from the claw portion 27b, the solenoid 30 is turned on and the variable power motor 40 is reversed. As a result, the first carriage 10 is brought to a predetermined lower position from above, and is fixed at a predetermined position by turning on the variable magnification sensor 56 and turning off the variable magnification motor 40. After a certain period of time has passed after the end of the reduction copy, when specifying the same size, or after turning on the main switch, the first carriage 10
And the mirror bracket 68 returns to the same magnification and directness.

In this case, the variable power motor 4 rotates forward and the feeler 61 rotates forward.
is the position where the abnormality sensor 62 is turned on, that is, the stop pin 16
is above the uppermost claw portion 27a of the stop lever 27.
It continues to rotate in the normal direction until it reaches the position of the second rib, and then rotates in the reverse direction and stops when the variable magnification sensor 56 turns on. As mentioned above, the drive pulley 38 and the mirror soft cam 64 are connected by a chain 60' and are configured to maintain a given optical position relative to each other.

Therefore, the positions of the first carriage 10 and the mirrors 66, 67 are simply determined by the feeler 6 which is interlocked with the drive pulley 38.
It is only necessary to detect the rotation angle position of 1. Therefore, control of the lens moving device 8 and the mirror unit 9 is very simple. Changes in the magnification positions of the lens moving device 8 and the mirror unit 9 are performed under program control using a microcomputer including a central processing unit CPU.

In FIG. 7, reference numeral 71 denotes a program control unit that performs magnification variable drive control during normal operation, and this program control unit 71
and the forward rotation output section 72 and the reverse rotation output section 7 of the variable power motor.
3, there is a program control section 7 due to noise etc.
In order to prevent runaway of 1, a safety circuit 7 consisting of a logic circuit is installed.
4 is provided. In this example, the safety circuit 74 is composed of a register consisting of inverters 75 and 76 and NOR gates 77 and 78. Normally, variable power drive control is performed by inverters 75 and 75 based on commands from the program control section 71.
Or through 76, the register is set or reset and the forward or reverse rotation output sections 72, 73 are turned on and off, but when the variable magnification sensor 62 is turned on, the forward rotation output section 72 is turned OFF,
Also, when the variable power sensor 56 is turned on, the reverse rotation output section 73 force F
F. In this way, by providing the safety circuit 74 that functions depending on the output state of the variable magnification sensors 56 and 62,
It is possible to prevent the program control unit from running out of control, thereby providing redundancy and performing safer and more reliable control. Naturally, the magnification change drive is not performed in the dark when the copying machine is in the print cycle. Next, the lens scanning section in the first carriage will be explained.

In FIG. 8, the scanner motor 80 includes a partial piece 81a having a concave portion of a slot 82 fixed to a portion 10b on the side plate 41 side of the first carriage 10, and a square bar-shaped partial piece 81.
b, a yoke 81 that can be divided into two parts, a plate-shaped permanent magnet 83 attached to the upper yoke piece 81a within the slot 82 of this yoke 81, and a bobbin with a coil wound thereon, and a slot below the magnet 83. 82 and a scanner motor bobbin portion 84 positioned around the lower yoke portion 81b with an appropriate clearance.

The scanner motor bobbin portion 84 is connected to the above-mentioned lens holder 13 via a bracket 85 located below the yoke portion 81b. The scanner motor bobbin section 84 is placed in the gap of the magnetic path including the magnet 83 and the yoke 81. Therefore, by passing a current through the bobbin section 84, the bobbin section 84 moves along the x direction in FIG. The lens holder 13 is moved through the bracket 85 by receiving thrust in the direction shown in FIG. The exit 11 provided in the first carriage must be shielded from light so that no light enters through the lens 7, no matter which position the lens holder 13 moves to.

Therefore, on the lower surface of the first carriage 10, shield curtains 86 extend from both sides of the lens holder 13 when seen in the moving direction of the lens holder 13, and the other ends of these shield curtains are connected to the green ends of the Sekiguchi 11. It is wound around shield drums 87, 87' which are rotatably held in shield holders 88, 88' provided nearby. Therefore, the area of Sekiguchi 11 other than the lens holder 13 is covered by this shield curtain 86. Also shield drum 87
, 87' are each provided with a toothed pulley 89, and a timing belt 90 whose both ends are fixed to the lens holder 13 is stretched around the both toothed pulleys 89. When the lens holder 13 moves, this timing belt 90
The shield drums 87, 87' rotate synchronously,
The shield drum on one side operates the shield curtain and the shield drum on the other side winds up the shield curtain. Therefore,
During the scanning movement, the force applied from the shield curtain 86 to the lens holder 13 is approximately constant, the scanning speed is stable, and high scanning accuracy is obtained. As before, the shield drum 87,
In the case where the 87' itself has a mainspring or the like and then always applies a force in the winding direction to the shield curtain 86 by return force, the force applied to the lens holder 13 varies depending on the scanning position of the lens holder 3, and the scanning accuracy It is inconvenient to increase the In order to detect the instantaneous scanning position of the scanner motor pobbin section 84, a rotary encoder 91 is attached to the side surface 81' of the yoke 81 opposite to the side plate 41. It is configured to rotate according to the amount of movement of the scanner motor pin section 84.

That is, the wire 92 is stretched between pulleys 93 and 94 located near both ends of the slot 82 on the side surface 81' of the yoke 81, and a pulley (not shown) of the encoder 91, and is connected to the bracket 85. There is. Although the pulley 93 is fixed, a pulley 94 is attached to one end of a lever 95 that is pivotally connected to the yoke side surface 81', and a spring 96 provided between the lever 95 and the yoke side surface 81' applies a constant tension to the wire. It is given to 92 people. In FIG. 9, lens position and speed detection means 91', which is comprised of a lens position signal from an encoder 91 and a circuit that processes the position signal and generates a speed signal, rotates as the lens 7 scans and generates a corresponding signal. and sends it to the lens scanning control section 97.

The control section 97 sends this signal to the photosensitive drum speed detection means 98.
control the output current to the bobbin section 84 of the scanner motor 80 so as to maintain the rotation of the photosensitive drum 100 at a predetermined speed corresponding to each specified magnification given from the lens speed specifying means 99; Therefore, lens 7
The scanning speed is controlled, and the scanning distance predetermined by each magnification is also controlled by the lens position signal. The lens holder 3 is designed to return to a predetermined position except when the machine is executing a print cycle, and a sensor (not shown) is provided on the first carriage 10 to detect the returned position. be. As mentioned above, the fact that the lens holder 13, which is the lens scanning means, is directly connected to the scanner motor 80, which is the driving means, makes it easy to control the lens scanning speed and also to change the lens scanning speed due to changes in magnification. Make it extremely easy. In the variable magnification optical device of the present invention, since the scanner motor 80 serving as a lens driving means is mounted on the first carriage 10, when changing the magnification, the scanner motor 80 and the lens scanning guide rods 12, 12
' are integrated and move together, greatly simplifying the drive mechanism for lens scanning.

This effect is the same even when a DC servo motor, step motor, or other device is used as the lens driving means. However, especially when using a linear motor, the bobbin section 8
4 can be directly connected to the lens holder 13. Therefore, stable scanning control can be achieved without causing a time lag between the motor operation and the lens operation, which would occur if gears, wires, etc. are used in between. can get.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a copying machine equipped with the variable magnification optical device of the present invention, Fig. 2 is an explanatory diagram of correction of the lens position with respect to the imaging position during reduction, and Fig. 3 shows the entire variable magnification optical device from the rear. This is a perspective view as seen from the side with a part cut away. Figure 4 is an explanatory diagram of the separation principle of lateral movement and vertical movement of the first carriage using wires and pulleys. Figure 5 is a variable magnification optical system. 6 is an enlarged view of the side plate of FIG. 3, FIG. 7 is a block diagram of the variable power drive control device, and FIG. 8 is a partially cutaway view of the device. FIG. 9 is a perspective view showing a portion of the carriage, and FIG. 9 is a block diagram of the lens scanning control device. IA... variable magnification optical section, IB...
・Copy section, 2...Manuscript layer board, 3,3
′...Lighting device, 7...Lens, 8.
・・・・・・Lens moving device, 9……Miffunit, 1
0...First carriage, 12, 12'...Guide rod,
13... Lens holder, 16""" Stop pin, 17
“””Slide roller, 18...Pu-IJ, 20...Second carriage, 21...Vertical support rod, 25
...Sekiguchi, 27...stop lever, 27a,
27b...Claw portion, 28...Stopper, 30...Solenoid, 33...Slice, 34...Sliding spring, 35, 36...Pulley, 38...Drive pulley, 39 ...Drive wire, 40...
...Variable power motor, 41, 42...Side plate, 43,
44... Guide rod, 45... Slide cam plate, 48... Worm gear, 49... Worm wheel, 50... V-shaped lever, 52, 53... Pulley,
54... Spring, 55... Feeler section, 56...
Variable power sensor, 57... Drive sprocket, 58...
Filler sprocket, 59...mirror sprocket,
60...Chain, 61...Fila, 62,63...
...Variable power sensor, 64...Mirror lift cam, 65...Mirror lift co. , 66, 67... Kofu, 69... Mirror guide, 71... Program control section,
72...Forward rotation output section, 73...Reverse rotation output section, 74...Safety circuit, 80...Scanner mode controller, 8
1...Yoke, 82...Slot, 83...Permanent magnet, 84...Scanner motor bobbin section, 85...
...Bracket, 91...Rotary socoder, 97...
... Lens scanning control section, 98 ... Drum speed detection means, 99 ... Lens speed designation means, 1
00...Photosensitive drum. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 5 Figure 6 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1. A variable magnification optical device for a copying machine that forms an original image on a photoreceptor driven by a drive motor via a lens and a mirror, the lens being positioned on the surface of the original. a first carriage having a guide rod that guides the guide rod so as to be linearly reciprocating in a direction defined as a scanning direction in a plane parallel to the first carriage;
a second carriage that supports and guides the carriage perpendicularly to the document surface and is movable in a direction parallel to the document surface and perpendicular to the scanning direction; a lens driving means that moves the lens along the guide rod; a lens scanning control device for controlling the lens driving means and scanning the lens at a predetermined speed; and a variable magnification motor for moving the first and second carriages and the mirror to predetermined positions when changing the copying magnification. and a means for controlling the variable magnification motor, wherein a dedicated scanner motor is mounted on the first carriage as the lens driving means, and the scanner motor moves together with the first carriage when the copying magnification is changed. None, the scanner motor is a linear motor consisting of a magnetic circuit including a permanent magnet and a yoke, and a coil provided in a gap in the magnetic circuit,
A variable magnification optical device characterized in that a lens is connected to a coil of this linear motor. 2. The lens scanning control device includes a photoreceptor speed detection means and a lens position/speed detection means, and based on the electric signals from both detection means, it controls the coil of the linear motor according to the speed fluctuation of the photoreceptor. 2. A variable magnification optical device according to claim 1, characterized in that the supplied current is controlled.