JPH0443858Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a copying apparatus that moves an original to be copied and exposes its image to a photoreceptor, and the invention is a copying apparatus that moves an original to be copied and exposes its image to a photoreceptor. This invention relates to a variable-magnification copying apparatus capable of making copies such as.

<Summary of the invention> The present invention changes the moving speed of, for example, a document table in a variable-magnification copying device by using two simple transmission devices: a transmission gear having a predetermined transmission ratio and coil springs with opposite winding directions. It is characterized by being operated by a clutch.

<Prior Art> In an original table-driven variable magnification copying device with a fixed optical system, in order to change the copying magnification, the imaging magnification of the original projected onto a photoreceptor is changed, and
The speed ratio between the original moving speed and the photoreceptor speed must be changed in accordance with the selected copying magnification. To be more specific, when the document moving speed is υ ₁ and the photoreceptor speed is υ ₂ , the speed ratio m is defined according to the following equation.

m=υ ₂ /υ ₁ , where m is the selected magnification. By changing the speed ratio according to the above equation, the magnification of the copied image in the photoreceptor movement direction, that is, the document copy magnification in the document movement direction, can be set to the selected magnification. Note that the magnification of the copied image in the direction perpendicular to the above direction is changed by changing the projection magnification of the optical image, as described above.

Incidentally, in many devices, the speed ratio is generally changed by changing the document moving speed without changing the photoreceptor speed. There is also a method in which the original is fixed and the original is scanned by a mirror and the image is slit-exposed onto a photoreceptor, but in this case as well, the relationship between the moving speeds described above is the same, and the original moving speed is the mirror's original scanning speed. corresponds to

As for a conventional mechanism for changing the movement of original documents and mirror scanning, for example, there is a transmission mechanism constructed of a large number of gears, as disclosed in Japanese Patent Laid-Open No. 58-68061.

<Problems to be solved by the invention> However, in the conventional mechanism described above, transmission gears corresponding to speed ratios are arranged in parallel, and a predetermined transmission ratio is selected by selectively meshing them according to each magnification ratio. Because of this, it is not only structurally complex, but also takes up a lot of space due to the arrangement of the transmission gears.
There is a drawback that the entire device cannot be miniaturized. Furthermore, since the transmission gears are not always in mesh, there is a possibility that the gears may be damaged during selection.

The present invention has been devised in view of these points, and an object thereof is to provide a variable magnification copying apparatus that has a simple structure, is easy to downsize, and is free from gear damage.

Another object of the present invention is to provide a variable-magnification copying apparatus that can perform variable-magnification copying by adding a transmission and replacing or switching the optical unit with almost no changes to the same-size copying apparatus.

<Means for Solving the Problems> In order to achieve the above object, the present invention, as illustrated in FIG. A variable magnification copying apparatus is used in which the copying magnification of the original 2 is made variable by changing the ratio between the speed of the photoreceptor 6 at which the image is formed, and the original 2 is
Alternatively, the means 32 for moving the photoreceptor 6 and the output shaft of the drive motor 16 can be connected by a clutch 31, and the output shaft of the drive motor 16 and the means 32 can be connected by a transmission 17. The transmission 17 can be connected by a clutch 42, and the transmission 17 is
Transmission gears 2 that mesh with each other and have a predetermined transmission ratio
3 and 25' are respectively attached to the input shaft 19 and the output shaft 20, one not being rotatable and the other being rotatable, and
Transmission gears 2 that mesh with each other and have a predetermined transmission ratio
5 and 23' are respectively attached to the input shaft 19 and the output shaft 20, one rotatably and the other non-rotatably. is both transmission gear 2
A coil spring 26 is disposed in contact with the transmission gears 23 and 25 to connect the transmission gears 23 and 25 by tightening and disconnect them by loosening the transmission gears 23 and 25.
On the outer periphery of the boss portion of 5', both transmission gears 23', 2
A coil spring 27 is disposed in contact with the transmission gear 5' to connect the transmission gears 23' and 25' by tightening and disconnect them by loosening the coil springs 26 and 27, and the winding directions of the coil springs 26 and 27 are opposite to each other. It is further characterized in that it includes a detent gear 28 to which one end of the coil spring 27 is attached, and a plunger pin 29 that can be engaged with the detent gear 28.

<Example> Hereinafter, the example shown in the drawings will be described in detail.

FIG. 1 shows an outline of the invention. Manuscript table 1
The upper original 2 receives light from an illumination lamp 3 and a reflection plate 4, and is exposed onto a photosensitive drum 6 through an optical lens 5, which is an optical variable magnification means selected to have a predetermined magnification. The photosensitive drum 6 charged by the charger 7 is
Due to the above exposure, the document image becomes a latent image in the developing device 8.
Developed with toner. The conveying roller 9 conveys the copy paper 11 at the same speed as the photosensitive drum 6, and the toner image on the photosensitive drum 6 is transferred onto the copy paper 11 by a transfer charger 10 and fixed by a fixing device (not shown). Excess toner on the photosensitive drum 6 is cleaned by a cleaner 12. optical lens 5
For example, this uses a self-occurring lens array (trade name of glass fiber lens array), and three lenses are arranged for reduction magnification, equal magnification, and enlargement magnification. It can be moved to a predetermined optical path.

The moving speed of the document table 1 must be changed depending on the selected magnification, but the optical lens switching device 13 sends a signal from the magnification detection means 14 to the control circuit 15, which detects that a desired lens is in the optical path. The speed of the output of the drive motor 16 is changed by the transmission device 17 in the transmitted and set speed mode, and the document table 1 is moved at a predetermined moving speed. The control circuit 15 drives the photosensitive drum 6, conveyance roller 9, etc.
The drum driving device 18 is actuated and controlled by.

FIG. 2 shows a sectional view of the transmission 17 which is the basis of the present invention. This configuration is a transmission device that has the function of increasing and decelerating the rotational speed of the input shaft 19. The input shaft 19 and the output shaft 20 are arranged at predetermined positions by a holding plate 22 via a bearing 21, and the speed change gears 23, 23' are fixed to the input shaft 19 and the output shaft 20, respectively, with fixing pins 24, 24. There is. The transmission gears 25 and 25' are connected to the input shaft 19, respectively.
and is rotatably attached to the output shaft 20. Then, the speed change gear 23 on the input shaft 19 side and the speed change gear 25' on the output shaft 20 side mesh, and the input shaft 19
transmission gear 25 on the side and transmission gear 2 on the output shaft 20 side
3' are engaged. The coil spring 26 on the input shaft 19 side is left-handed, and is fitted onto the boss portions 23a, 25a of the transmission gears 23, 25 on the input shaft 19 side, and is in contact with the flange portions 23b, 23b with light contact pressure. . Further, the coil spring 27 on the output shaft 20 side is right-handed, and is fitted onto the boss portions 23a', 25a' of the transmission gears 23', 25' on the output shaft 20 side, and is lightly attached to the flange portion 23b'23b'. They are brought into contact with each other with contact pressure, and one end portion 27a thereof is engaged with the detent gear 28. The detent gear 28 is fitted around the coil spring 27, and its rotation is regulated by a plunger pin 29. In addition, the transmission gears 23', 23' and the transmission gears 25', 2
5' is set to the gear ratio according to the magnification ratio, for example, when the magnification ratio is in enlargement mode, from A4 size to B4 size,
If you change from B4 to A4 in reduced mode, from that ratio,
The ratio is 50:39, and the number of teeth should be configured according to that ratio.

FIG. 3 is a state diagram showing the action of each part and the force transmission path during speed increase or deceleration in the configuration of FIG. 2.

Now, if you want to increase the speed, plunger pin 2
9 to the “ON” state, and set the date tent gear 28.
The plunger pin 29 is removed from the input shaft 1 so that the detent gear 28 can freely rotate.
9 is rotated clockwise (CW), the speed change gear 25' on the output shaft 20 side, which is meshed with the speed change gear 23 fixed to the input shaft 19, rotates counterclockwise (CCW). At this time, the output shaft 20
Since the side coil spring 27 is right-handed,
From the contact pressure with the flange portions 23b' and 25b',
The gears 25' and 23' on the output shaft 20 side are in a fixed state, and the output shaft 20 transmits force in the CCW direction at that gear ratio. The transmission gear 25 on the input shaft 19 side receives force from the transmission gear 23 on the output shaft 20 side and rotates in the CW direction, but rotates faster than the transmission gear 23 depending on the gear ratio. At this time, since the coil spring 26 on the input shaft 19 side is left-handed, it becomes loosened and no force is transmitted. On the other hand, in the deceleration mode, the plunger pin 29 is in the "OFF" state, and the rotation of the detent gear 28 is prevented. Therefore,
Even if the speed change gear 25' on the output shaft 20 side rotates in the CCW direction, the coil spring 27, one end of which is held by the detent gear 28, remains in the boss portions 25a', 23.
There is always a gap between it and a', and it never tightens, so there is no transmission of force. In this state, since the coil spring 27 is clockwise wound on the input shaft 19 side, the flange portions 23 of the transmission gears 23 and 25
b, 25b, and the transmission gear 23 and the transmission gear 25 on the input shaft 19 side are tightened by the coil spring 26 to be in a fixed state, and force is transmitted. That is, the input shaft 19
The output shaft 20 that meshes with the transmission gear 25 on the side
Power is transmitted to the side transmission gear 23', and the output shaft 20 is fixed to this transmission gear 23' with a pin 24.
rotates. The rotation of the output shaft 20 is reduced by the gear ratio of the speed change gears 23' and 25.

FIG. 4 shows the driving of the document table 1, but only with the same magnification and without any variable magnification. A clutch 31 and a document 2 are mounted on the output shaft 16a of the drive motor 16.
A document table drive sprocket 32, which is a means for moving the document table, is disposed, and the clutch 31 is operated intermittently by a control circuit 15 shown in FIG. 1 at the timing of the exposure process. Now, when the exposure process begins, the clutch 31 operates as the drive motor 16 rotates, and the output shaft 16a of the drive motor 16 is activated.
The original table driving sprocket 32 is connected to the original table driving sprocket 32, and the original table driving chain 33 moves in the direction of the arrow. Appropriate tension is applied to the document table drive chain 33 by an idler sprocket 34 so that there is no slack. A drive pin 35 is attached to a part of the document table drive chain 33, and this drive pin 35 is engaged with a long hole 36a of a guide plate 36 fixed to the document table 1. Therefore, the original table drive chain 33
Although the document table 1 moves in one direction, the document table 1 can reciprocate between the axes of the sprockets 32 and 34 and by the diameter of their pitch circle. The document table 1 is equipped with a slide bearing (not shown) so that the direction of movement can be regulated and the document table 1 can be smoothly moved.

FIG. 5 is a sectional view showing a structure in which a transmission device 17 of the present invention is added to the drive means for the original table 1 dedicated to the same magnification shown in FIG. This is as explained in the figure.

In Fig. 5, drum system drive sprocket 3
Reference numeral 7 is for driving the photosensitive drum 6, conveyance roller 9, and developing device 8 shown in FIG. It matches. The transmission gear 40 is for transmitting driving force to the transmission device 17 of the present invention, and is fixed to the output shaft 16a of the drive motor 16 with a fixing pin 24 and meshed with the transmission input gear 41. Gear 4 for speed change input
1 is fixed to the input shaft 19 with a fixing pin 24, and transmits driving force. A clutch 42 is coaxially attached to the output shaft 20, and a fixing screw 44 is attached to the clutch plate 48.
A speed change output gear 43 mounted in the above is attached. An idler gear 45 meshes with the variable speed output gear 43 and transmits the driving force of the variable speed output gear 43 to the original table drive gear 47 . moreover,
A clutch 31, a document table drive gear 32, and a document table drive sprocket 32 are coaxially arranged on the output shaft 16a of the drive motor 16.
A clutch plate 48, a document table drive gear 47, and a document table drive sprocket 32, which is a means for moving the document 2, are fixed by fixing screws 44, and are rotatable with respect to the output shaft 16a.

In the above configuration, in the equal magnification mode, the clutch 42 is "OFF", the output shaft 20 and the speed change output gear 43 are not connected, and the clutch 31
is “ON”, and the output shaft 16 of the drive motor 16
A, the original table drive gear 47, and the original table drive sprocket 32 are connected, so that the same effect as in FIG. 4 is obtained.

On the other hand, to set the magnification ratio mode, that is, the reduction or enlargement mode, the clutch 31 is turned "OFF".
and turn clutch 42 “ON”. Then, since the clutch 31 is "OFF", the output shaft 16a of the drive motor 16 and the original table drive sprocket 32 are not connected, and the clutch 42 is not connected.
is “ON”, the output shaft 2 of the transmission 17
In other words, the drive motor 16 is connected to the original table drive sprocket 32 via the transmission 17. In this speed change mode, the selection of reduction or expansion is made by the plunger pin 2 using the plunger coil 30.
This can be done by turning 9 "ON" and "OFF" as explained in FIGS. 2 and 3.

With such a simple mechanism, three desired speeds, ie, reduction, enlargement, and same-size modes, can be selected by electrically controlling two clutches and one plunger pin.

The present invention can also be applied to a copying machine in which the speed of the photoreceptor is changed in accordance with the selected magnification.

The present invention can also be applied to a mirror drive device of a copying machine that scans an original and exposes the image onto a photoreceptor through a slit.

Furthermore, the operation of the plunger pin may be mechanically linked to an optical lens switching mechanism, which will not be described in detail.

<Effects of the Invention> As explained above, the variable magnification copying apparatus according to the present invention can be controlled to three speeds by controlling two clutches and one plunger pin, and operates reliably. Further, since the present invention is mechanically simple, it has an advantage in terms of miniaturization compared to the conventional method. Furthermore, since the transmission gears of the transmission device are always in mesh, the transmission gears are not damaged when selecting the transmission ratio. Furthermore, by adding a speed change device and a lens switching means for variable magnification without making any mechanical changes to the same-size copying device,
The variable magnification copying apparatus of the present invention can be easily constructed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the construction of an embodiment of the variable magnification copying apparatus of the present invention, and FIG. 2 is a sectional view of the main parts of the transmission.
FIG. 3 is an explanatory diagram of the operation of the transmission, FIG. 4 is a diagram showing the driving of a document table with only the same magnification, and FIG. 5 is a structural diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Original table, 2... Original, 5... Optical lens, 6... Photosensitive drum, 13... Optical lens switching device, 14... Magnification detection means, 16... Drive motor, 17... Transmission device, 18...Drum drive device, 19...Input shaft, 20...Output shaft, 23,
23', 25, 25'...speed gear, 26, 27...
...Coil spring, 28...Daytent gear,
29...Plunger pin, 31, 42...Clutch, 32...Document table drive sprocket.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) By changing the ratio between the moving speed of the original 2 and the speed of the photoreceptor 6 on which the optical image of the original 2 is formed via the optical variable magnification means 5, the original The variable magnification copying apparatus is capable of varying the copying magnification of the document 2 or the photoreceptor 6, and the means 32 for moving the original 2 or the photoreceptor 6 and the output shaft of the drive motor 16 can be connected by a clutch 31. The output shaft of the drive motor 16 and the means 32 can be connected by a transmission 17 and a clutch 42, and the transmission 17 has transmission gears 23 and 25' which mesh with each other and have a predetermined transmission ratio. One is attached to the input shaft 19 and the output shaft 20 such that one is not rotatable and the other is rotatable, and transmission gears 25 and 23' having a predetermined gear ratio and meshing with each other are attached to the input shaft 19 and the output shaft 20, respectively. Both transmission gears 23, 2 are mounted rotatably and the other is non-rotatably, and further mounted on the input shaft 19.
On the outer periphery of the boss part of No. 5, both transmission gears 23, 2
A coil spring 26 is disposed in contact with the transmission gears 23 and 25 to connect the transmission gears 23 and 25 by tightening and to disconnect the transmission gears 23 and 25 by loosening them.
On the outer periphery of the boss part of 25', both transmission gears 2 are attached at both ends.
3', 25' and the above-mentioned two transmission gears 23',
A coil spring 27 that connects by tightening and disconnects by loosening is arranged with respect to 25', the winding directions of both the coil springs 26 and 27 are opposite to each other, and the end of one of the coil springs 27 is A variable magnification copying apparatus comprising an attached detent gear 28 and a plunger pin 29 that can be engaged with the detent gear 28. (2) In the variable magnification copying apparatus according to claim 1 of the above utility model registration, the plunger pin 29 of the transmission device 17 is interlocked with the switching device of the optical magnification variable means 5, or is added to the switching device. A variable magnification copying device adapted to be activated by a signal from a magnification detection means.