JPS59123831A - Variable power optical device - Google Patents

Abstract

PURPOSE:To reset easily a scanner even in case when a machine is stopped on the way of scanning by a registration transfer system color copying machine, etc. by providing a one-fixed point claw clutch for a variable power. CONSTITUTION:A desired solenoid 106 is operated by a desired copying variable power push-button, prescribed one-fixed point claw clutches 39-41 are set, gears 42-44 are rotated, a driving shaft 33 is rotated in inverse proportion to a variable power (m), the first mirror and a light source lamp are driven by a pulley 30 by 1/m.V of an unmagnification speed, and the second and the third mirrors are driven at a half speed. In the event of a service interruption in the course of an operation, the solenoid 106 is turned off, a blade driving lever 104 is displaced by a spring 107, the outside diameter of a pawl release blade 103 is expanded, a pawl roller 102b of a hook pawl 102 is pushed up, and an engagement of a pawl 102a and a groove 101a of a wheel 101 is released, therefore, the reset can be executed without any trouble by a scan return servomotor 29.

Description

TECHNICAL FIELD The present invention relates to a variable magnification electrophotographic copying machine, and more particularly to a variable magnification optical device for a color variable magnification electrophotographic copying machine of a three-color separation image overlapping transfer system.

In a conventional color electrophotographic copying machine using a three-color separation image superimposition transfer method, for example, as shown in FIG. is illuminated by the light source 4 through the slit, the first mirror 5, the second mirror 6, the third mirror 7, the imaging lens 8, and the fourth mirror 9, and then onto the photosensitive drum 10! The image is formed at a fixed position and exposed.

As is known, the same-magnification slit exposure using the above-mentioned optical device is performed by integrating the light source 4 and the first mirror 5 into a photoreceptor drum lO.
The second mi.
This is done by moving the mirror 6 and the third mirror 7 as one body in the same direction at a speed of %V.

Between the fourth mirror 9 and the photosensitive drum 10, blue, green,
A color separation filter 11 for three colors of red is provided so as to be switchable and insertable in the forward path. Around the photoreceptor drum 10, following the exposure position, there are three developing units 12, each containing a developer containing toner of three colors: yellow, magenta, and cyan.
1j and 14 are disposed, and the latent images formed by exposure with light beams passed through the front, green, and red color filters are yellow, magenta, and cyan color developers 12, 13, 1, respectively.
4, three color toner images are sequentially formed.

At a position after the three developing devices, a transfer drum 15 is provided in contact with the circumferential surface of the photoreceptor drum 10 and has the same outer diameter as the photoreceptor drum 10, and rotates at the same circumferential speed in synchronization with the rotation of the photoreceptor drum 10. At the contact position, they are rotated at a linear velocity in the same direction. A transfer paper 17 is fed to the transfer drum 15 from a paper feeder 16, and its leading end is clamped to a predetermined length by a mechanical clamper 18, and wound around the drum 15. The toner image is transferred by the transfer charge roller 9 provided inside and rotated three times to produce yellow 1. Three color toner images, magenta and cyan, are transferred in a superimposed manner. Thereafter, the transfer paper 17 is peeled off from the rolling drum 15, fixed by the fixing device 2o, and discharged onto the paper discharge tray 21 to complete a full-size color copy.

Now, in a slit exposure scanning type copying machine, when copying a document by changing the magnification such as same size, reduction and/or enlargement, the lens and mirror of the exposure optical device are displaced according to the copying magnification, and It is necessary to change the document scanning speed.

To explain this in more detail, in an optical device with a fixed document table and a moving scanner, the magnification function is to match the vertical direction (perpendicular to the scanning direction) and horizontal direction (scanning direction) of the document to the required magnification. It is important to When changing the magnification in the vertical direction with an exposure optical system that has the same lens and mirror arrangement as the optical system of the color copying machine shown in Figure 1, the second
As shown in the figure, with the light source 4 and the first mirror 5 fixed at the reference position, the second mirror 6, the third mirror 7, and the lens 8 are moved from the same magnification position shown by the solid line, depending on the magnification ratio. is displaced to the position shown by the chain line in the figure. In that case, the second
The mirror 6 and the third mirror 7 are located at a position further away from the first mirror 5 than at the same magnification (for example, 6') during reduction and enlargement.
, 7'), but the lens 8 is moved closer to the fourth mirror 9, for example, to a position 8', during reduction, and to a position, for example, 8'', closer to the third mirror 7, when enlarged.

FIG. 3 shows an example of a lens and mirror moving device that moves the second and third mirrors 6.7 and lens 8 in relation to each other in accordance with the magnification ratio as described above, and scans an original. FIG. 3(,) shows a lens and mirror displacement mechanism for variable magnification, in which a stepping motor 22 for driving the lens is rotated by a screw shaft 24 via a gear train 23, and a lens bracket 25 to which a lens 8 is fixed is shown. When the lens is moved to the left in the drawing when it is being reduced, and to the right when it is being enlarged by an amount corresponding to the magnification ratio, the cam plate 26 that is integrally attached to the lens bracket 25 is also moved left and right at the same time. An arc-shaped slit cam 26a is formed on the cam plate 26, and a cam follower 28a provided at one end of an L-shaped variable power drive lever 28 that is swingably supported on a fulcrum 27 is engaged with this cam. It matches. The engagement position of the cam 26a at the same magnification is at the most downwardly protruding position in the figure, and the amount of protrusion decreases from there to the left and right. Therefore, even if the lens bracket 25 moves to the left or right during reduction or enlargement, the cam follower 28a is displaced upward in the figure, and the variable power drive lever 28 is accordingly rotated counterclockwise and its upper end is displaced to the left from its original position. As a result, by the arrangement of the rope and pulley shown in Figure 3(b),
When the light source 4 and the first mirror 5 are fixed, the second and third mirrors 6.7 are displaced to the left in the figure. (Note that the arrangement of lenses and mirrors in Fig. 3(b) is reversed from Fig. 2.) In this state, stop the lens drive stamping motor 22 and rotate the scan drive pulley 30. As a result, the light source 4 and the first mirror 5 are moved at a certain speed, and the second, third and third mirrors 697 are synchronously displaced in the same direction at half the speed, thereby performing exposure scanning.

Since the circumferential speed of the photosensitive drum cannot be changed by the process speed, it must be maintained at a constant speed V regardless of the copying magnification. Therefore, the scanning speed of the light source 4 and the first mirror 5 is set to
m % By setting the speed of the second and third mirrors to 772 m, the horizontal magnification of the document is adjusted to m.

For this purpose, the scanning drive pulley 30 shown in FIG. 3(b) is set at a copying magnification of V? : It is necessary to drive at a rotation speed proportional to hardness. Note that the reference numeral 29 in FIG. 3(b) is a scan return servo motor.

The present invention relates to control of the rotational speed of the scan drive pulley 30 and the timing of its start/stop.

Conventionally, as a method for driving a scanner drive pulley according to the copying magnification of the variable magnification optical device of a variable magnification copying machine, (a) gear trains as many as the number of variable magnifications are provided between the drive source and the scanner drive pulley. , is switched and driven via an electromagnetic clutch, etc.

(b) A servo motor or pulse motor is used as the drive source, and the speed is switched and driven by electrical control means.

Such methods are known.

However, both of these methods require a switching step of an electromagnetic clutch or an electric control means, which inevitably causes a shift in the scanning start position every image forming cycle.

In a color electrophotographic copying machine that uses a three-color separation image overlapping transfer method, the most important thing is the alignment of the transferred images, so the variable magnification drive method described above is inappropriate for a color copying machine, and for this reason The reality is that a superimposed transfer type color electrophotographic copying machine with a variable magnification mechanism has not yet been realized. .

Although this is not a variable magnification copying machine, there is one that uses a constant-point meshing latte as an optical scanning drive means that does not cause positional deviation.

By the way, in the fixed point meshing latte conventionally used in the optical system scanning drive device of a copying machine, for example, an engagement groove is provided on a rotary disk that is rotationally driven by a drive source, and the meshing groove is interlocked with the optical system scanning drive pulley. The claw part of the engaging claw is pivotably supported on a rotating member by a spring or the like so as to press against the circumferential surface of the rotating disk, and the engaging groove of the rotating disk is at the position of the claw. When they come, they engage with each other and the clutch is engaged. When the optical scanning is completed, the end of the release pin provided at a predetermined position on the machine is pressed down against the claw part of the 9 engaging claws, against the force of the spring. It was like breaking the connection between the claw and the groove.

Therefore, if the power is turned off due to a power outage or erroneous operation during optical scanning, or if the machine stops operating due to some kind of failure, the clutch's engaging pawl and engaging groove will remain engaged, and the scanner will The reset method becomes very complicated.

Purpose of the Invention In view of the above-mentioned circumstances of conventional variable-magnification copying machines and optical scanning drive clutches, the present invention is applicable not only to monochrome copying machines but also to color copying machines using an overlapping transfer method, in the event of scanning failure. To provide a variable magnification optical device capable of easily resetting a scanner even when the operation of the machine stops midway.

Configuration The present invention will now be described in detail based on embodiments shown in the drawings.

FIG. 4 is a perspective view showing a scanning speed switching unit that enables variable magnification copying in the color electrophotographic copying machine of the type previously explained with reference to FIG. In the embodiment shown in the figure, as an example, the copying magnification m is 3 of l, l'-143,0,7647.
It is possible to switch between types.

The scanning speed switching device section includes an input shaft 31. clutch shaft 32
, three shafts of the drive shaft 33 are provided parallel to the axis of the photoreceptor drum 10 and supported by a side plate (not shown).

The input shaft 31 is provided with an input pulley 35 and two gears 36 and 37, which are driven by a main motor of the copying machine via a timing belt (toothed belt) 34.

The clutch shaft 32 includes a gear 38 that engages with the gear 36 described above to obtain a speed and ratio such that the clutch shaft 32 has the same rotational speed as the photosensitive drum IO, and three fixed-point engagement claw lattes 39 and 40. , 41, and the gear 4 which rotates integrally with the clutch shaft 32 when these clutches are engaged.
2, 43, and 44 are provided.

The other gear 37 provided on the input shaft 31 includes a gear 46 fixed to the shaft 45 of the photosensitive drum IO.
and 38 mesh at the same speed ratio.

A gear provided at one end of the photoreceptor drum 1O meshes with a gear provided at one end of the transfer drum 15, which has the same diameter as the photoreceptor drum 1O, and thereby the photoreceptor drum 1O and the transfer drum 15 are connected to each other. The main motor rotates in synchronization with the clutch shaft 32 at the same rotational speed.

The structure of the fixed point meshing pawl clutches 39, 40, and 41 will be explained with reference to FIGS. 5 and 6.

This clutch includes a wheel lot fixed to the clutch shaft 32 and having an engaging groove 101a around the clutch shaft 32, and
The hook is swingably supported at one point on each side of the gears 42, 43, and 44 and has a hook portion 102a at one end that can be held in the groove 1ota. A claw roller 10 provided near the claw 102a of 102
A claw release blade 103 whose outer diameter is expandable and retractable, and a blade drive lever 104 which switches the outer diameter of the claw release blade 103 between an enlarged state and a contracted state, are engaged with each other. Claw 10 in groove 101a
A release pin 10 that releases the engagement of the catch claw 102 rotated together with the gear at a predetermined position when 2 & is engaged.
It consists of 5 and more.

The claw V-IJ-zbund 103 has a unit blade toaa having a rotation center 103c at the l end and a blade roller 103d at the other end as shown in FIG. 6(e).
), two discs are rotatably attached to each side of a disc 103b that is immovable with respect to the machine frame through a rotation center to3c'i pin. Blade driven leno<-
Unit blade 103a provided on the surface opposite to 104
The mounting hinge and blade roller 103d pass through the oblong relief holes 103e and 103f provided in the unit blade 103a on one side of the blade drive lever to drive the blade.
It stands out towards 4.

As shown in FIG. 6(f), the blade drive lever 104 has four grooves 10 around which the blade rollers 103d engage.
4a and one arm protruding semi-radially 04b
A plunger of a renoid 106 and a spring 107 are connected to the tip of the arm 104b.

Therefore, when the renoid 106 is energized, the arm 104b of the blade drive lever 104 is pulled, and the blade drive lever 104 is rotated by a certain angle, and the groove 1
The blade roller 103d that engages with 04B is the clutch shaft 3
2, the outer periphery of the pawl release blade 103 changes from the position shown by the chain line to the position shown by the solid line as shown in FIG. As shown in FIG. 6(a)vc, the claw roller 102b is pushed out by the outer periphery of the claw release blade 103, and the claw tip 102a is retracted from the outer periphery of the wheel 101, so that even when the wheel 101 rotates, the claw 10 is not caught.
2 is stationary together with the gear supported by this shaft, but when the outer diameter of the pawl release blade 103 is reduced,
), the claw roller 102b of the claw 102 approaches the wheel 101, the claw tip 102a slides on the outer peripheral surface of the wheel 101, and when the groove 101a rotates, it engages with the groove 101a. Gear 42, j3 with a box attached
Or 44 rotates integrally with the wheel 101. In other words, the clutch engages.

When the claw 102 rotates by a predetermined angle, the end of the hook 102 on the opposite side of the hook is pushed down into the release bin 105, and the hook 102 is inserted into the groove Iota between the claw 102a and the wheel 101.
The clutch is disengaged and the clutch is disengaged.

As described above, as the clutch shaft 32 rotates, the wheels 101 of each clutch rotate in synchronization with the photosensitive drum 10 at the same rotational speed. Photosensitive drum I of the pawl engagement groove 101a of the clutch wheel for each copying magnification m
As shown in FIG. 7, the deviation angle θm from the reference position of the wheel corresponding to the reference position of O is set as follows in proportion to the copying magnification m.

Each port 101a of the wheel 101 of each clutch is connected to the photoreceptor drum 10 via each shaft 4s, 31, 32' [fixed gears: 46, 37, 36, 38, respectively]. Since each groove 101a always corresponds to a certain position on the photosensitive drum, the wheels 101 of the photosensitive drum IO tok latch always rotate in synchronization. On the other hand, the winter melons 102 that engage with each of the clutch wheels 101 wait for their respective home positions to be at positions corresponding to their respective magnification ratios with respect to the starting point on the document table. The declination angle from the reference position of each port 101a of the wheel 101 is the same for each magnification ratio m, and the declination angle θm is the next gutter.

Copy magnification (→ θm 1 14.324°0.76
47 1.0.953°1.143
16.372° As shown in FIG. 4, gears 47 and 48 mesh with gears 42 and 43° 44, which are connected to the clutch shaft 32 by the clutches 39 and 40° 41, respectively.
, 49 are provided integrally with the drive shaft 33. gear 42
The gear ratios of 47.43, 8.44 and 49 are set as follows.

Gear Copy magnification (m) Gear ratio 42, 47
1 1 43.48 1.143 1/1.14344
．． 49 0.7647 110.7647 That is, the gear ratio of each gear train is inversely proportional to the copying magnification m.

A scanning drive IJ 30 is fixedly attached to the drive shaft 33, and the mirror drive wire shown in FIG. 3(b) is wound around it. This drive wire is also wound around a pulley provided on the shaft of the scan return servo motor 29.

The operation of the variable magnification drive device configured as described above will be explained below.

When the copying machine is turned on and a desired copying magnification is selected using a push button switch, etc., the renoids 106 corresponding to the selected magnification are turned on, and the above-mentioned action causes the fixed point engagement pawl corresponding to that magnification to be turned on. When the latte 39, 40 or 41 is engaged, the gears 42, 43 and 44 rotate integrally with the clutch shaft. In this case, the drive shaft 33 rotates at a rotation speed inversely proportional to the copying magnification m, and the wire rope wrapped around the scanning drive boot 930 moves the first mirror and the light source lamp at a scanning speed V at the same magnification. The mirror is driven at l/rri, and the second and third mirrors are driven at half that speed. In this way, scaling of the document in the lateral direction (scanning direction) is achieved.

Generally, when the scanner starts scanning, it is unavoidable that the scanner vibrates.
The reference end position of the photosensitive drum IO is shifted from the starting position and placed on the contact glass 2, and the starting position of the photosensitive drum IO is shifted by LDm from the image forming reference position, as shown in FIG.

In this example, Lg is set to 15th tone,
When copying at the same size, LDm = Ls = 15 cabinets.

Copy magnification m = l Xm = 0.7647, m =
Clutch wheel 1 corresponding to each of 1.14.3
．． The position of the engaging groove 101a provided on 01 is as described above with respect to m = 1, θm = 14.324゜m = 0.7647〃 θm = 10.95
3゜m = 1.143 II θm = 16
．． The diameter of the photosensitive drum IO and the diameter of the scanning drive boob I730 are both 12 (1 mm).
It is set to nine. Photosensitive drum IO and clutch shaft 32
Since it rotates at the same rotational speed in synchronization with
is as follows for each magnification.

"Dm = 15 tan X (θm / 14.3
24°) Copy magnification (→ LDm 1 15 ■0.764
7 11.47 Earthquake 1.143
17.154 songs, LDm
is proportional to the magnification m.

However, since the scanning drive pulley 30 rotates at a speed inversely proportional to the magnification m, Ls = LDm/m9, and Ls is always maintained at a constant value of 15 mm. Therefore, the distance L8 between the scanner start position and the document reference edge position does not need to be changed depending on the magnification, and the image leading edge position (reference position) on the photosensitive drum remains the same regardless of the magnification.

Since the present invention employs a constant-point engagement pawl latte as the variable magnification clutch, the timing at which the clutch engages is extremely accurate for the selected magnification, and the leading edge of the image on the photoreceptor drum never misses the position. Therefore, not only monochrome copying but also color copying using the three-color separation image overlay system can be made at variable magnification.

Now, when the clutch corresponding to the selected magnification is engaged and the gear corresponding to the clutch rotates by a predetermined angle, the tail of the hook 102 is released as described above.
tc is pressed, the engagement with the wheel IoI groove 101a is disengaged, and the rotation of the drive shaft 33 and scanning drive boob IJ30 is stopped. At this time, the catch claw 102 turns on a microswitch (not shown) to turn on the scan return servo motor 29, and drives the mirror drive wire rope in the opposite direction to the scan direction to return the scanner to the scan start position.

If there is a power outage or the power is accidentally turned off during the scanning operation, the renoid 106 is turned off, the blade drive lever 104 is pulled by the spring 107 and displaced, and the outer diameter of the pawl release blade 103 is expanded. The hook pushes up the claw roller 102b of the claw 102 and connects the claw 102a with the wheel /l/10
Since the engagement with the groove 1O1L of No. 1 is disengaged, the reset by the scan return servo motor 29 is performed without any problem.

Effects As described above, according to the present invention, it is possible to reliably prevent positional misregistration on the photoconductor during variable magnification copying, so it is possible not only for monochromatic copying but also for colors where the occurrence of misregistration is the most problematic. By being able to perform variable magnification copying even for color electrophotographic copying machines using the separation image superimposition method, it is possible to obtain color copies without any color shift, and in the unlikely event of an accident such as a power outage or erroneous operation during scanning. Even if the machine stops, you can easily reset the scanner.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the schematic configuration of a known color separation image superimposition type color electrophotographic copying machine, and FIG. A schematic diagram illustrating the variable power system. FIG. 3(a) is a side view showing the main parts of the lens and mirror drive system of the variable power system shown in FIG. 2, and FIG. 3(b) is a diagram showing the entire mirror drive wire system. FIG. 4 is a perspective view schematically showing the configuration of the variable magnification scanning drive section of the present invention, and FIG. 5 is an exploded perspective view showing an example of a constant-point engagement pawl clutch used in the device of the present invention. 6 is an exploded view showing its constituent members, and FIG. 7 is a schematic view showing an example of the position of the pawl of the clutch and its engaging groove.
FIG. 8(,) is a schematic diagram showing the relationship between the scanner start position and the document placement reference position in the present invention, and FIG. 8(b) illustrates the corresponding relationship between the image forming reference position of the photoreceptor drum and the start position. 30...Scanning drive pulleys 39, 40, 41...Constant point engagement clutch 42
, 47 ; 43 , 48 : 44 , 49... Gear train 101... Wheel 102... Catch is pawl 103... Pawl release blade 104... Blade drive lever 105... Release pin 106...・Nrenoid Figure 6 (e) (f) Figure 7 (a) Special I [Applicant'AJi]
Mme 1 installment) Name (674) Ricoh Co., Ltd. 4 Agent fi Address: Tokyo Kogyo; [2-32-4 Nishi-Shimbashi, Miyako Minato-ku
No. Kaji Kogyo Building Telephone (433) 45'64" Postal code 1056, Drawing subject to amendment 7, Attached sheet with amendment details

Claims (1)

[Claims] In the variable magnification optical device of a variable magnification electrophotographic copying machine, the optical scanner is moved in the scanning direction by a single scanning drive pulley via a shear wire rope at a speed inversely proportional to the copying magnification to change the magnification in the scanning direction. A number of gear trains corresponding to the number of variable magnifications are provided between the power source and the above-mentioned scanning drive pulley, and fixed point meshing lattes are provided that connect and disconnect each of these gear trains and the above-mentioned drive source, respectively. and the constant point engaging clutch is connected by energizing the renoid, which connects the engaging pawl provided on the rotating member interlocked with the scanning drive pulley and the fixed point of the member that is rotated by the drive source. 1. A variable magnification optical device characterized in that the zooming is performed by engagement with a meshing groove, and the engagement is disengaged when power to the lensoid is cut off.