JPS6355069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a release mechanism for a device for preventing rotational deviation of a rotating drum in an electrophotographic copying apparatus having a rotating photosensitive drum.

Conventionally, in this type of electrophotographic copying device, when replacing the sheet-like photoreceptor stretched over a rotating drum, the drum was removed from the device body and the photoreceptor was replaced, which was time-consuming. there was. In addition, a method has been proposed in which the photoreceptor can be replaced without taking the drum out of the device, but in this case, the drum and the pin that drives it are removed in order to prevent a phase shift between the rotation of the drum and the operation of other mechanisms. The drive means, etc., are designed to be integrally connected. Therefore, it is necessary to manually disconnect the connection to remove the load on the drive system, etc., and then reset the photoreceptor to its original state after replacing it. As a result, this reset is often forgotten and the copying There were times when it became impossible.

Furthermore, conventionally, in order to integrate the rotary drum driving means and the rotary drum during driving, it was necessary to engage a pin installed in the drive shaft with an engagement hole provided in the rotary drum, so that when the engagement was released, Since a lever is required for this purpose, a release operation is required separately from the lid opening operation, and since the release lever rotates, the operability of the device is poor and there are problems in making the device more compact.

Further, an additional operation is required to store the lever after the engagement is released. Therefore, in order to prevent the above-mentioned drawbacks of the device, the present applicant proposed in Japanese Patent Application No. 53-104844 (Japanese Unexamined Patent Publication No. 55-32052) that a rotatable drum is pushed from one direction by a cam-shaped driving member. We have proposed a rotating drum drive mechanism that allows the drum to rotate, and therefore, when the drive system is stopped, the drum can be easily rotated manually without being subjected to any load from the drive system, etc. in the direction of rotation. . The application further states that when the drive member is stopped, in order to prevent rotation due to the inertia of the rotating drum and to prevent a phase shift between the rotating drum and the drive system, one end of the drive member is fixed to the drive system side and the other end is substantially fixed. It also has a mechanism that prevents inertial rotation of the rotating drum by tightening the spring when a phase shift occurs between the drive member and the rotating drum, by wrapping a spring that is free in its position around the rotating part of the rotating drum. It is written as follows.

By the way, some electrophotographic copying machines are of a type in which the photoreceptor can be replaced manually by opening the top cover installed almost above the rotating drum and rotating the rotating drum to the desired position. In this case, the rotating drum must be disconnected from the drive system and must be able to rotate freely in either direction. However, in an electrophotographic copying apparatus equipped with the above-mentioned rotary drum drive mechanism, although the drum can be rotated freely in one direction, it cannot be rotated in other directions, which is inconvenient when replacing the photoreceptor.

The present invention has been made in view of the above points, and aims to enable a rotating drum equipped with an inertial rotation prevention mechanism to freely rotate. A blocking member that can take a locked state that prevents displacement when the drum is displaced relative to the driving member and a non-locked state that does not prevent the displacement, and a lid member that can be opened and closed around the rotating drum. The blocking member is configured to be switched between a locked state and a non-locked state in conjunction with the opening/closing operation of the lid member.

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

In order to facilitate understanding of the present invention, first, FIG. 1 schematically shows a transfer type electrophotographic copying apparatus with a movable document table employing the drive member release mechanism of the present invention.

In the figure, an original (not shown) placed on a moving original table 1 is irradiated by an irradiation lamp 2 as the original table 1 moves, and the reflected light from the original is reflected by an optical system consisting of a reflecting mirror 3 and a lens 4. The image is projected onto a sheet-like photoreceptor 6 stretched over a rotating drum 5 through a system. The photoreceptor 6 is uniformly charged in advance by a charging electrode 7, and when reflected light from the original is projected onto the photoreceptor 6 through the optical system, an electrostatic latent image of the original is formed on the sheet-like photoreceptor 6. is formed. The electrostatic latent image is developed into a visible image (toner image) by the developing device 8, and is further transferred by the transfer pole 12 onto the transfer paper fed from the paper feed tray 9 by the feed roller 10 and the paper feed roller 11. Ru. The transfer paper bearing the toner image is separated from the rotating drum 5 by a separation claw, and then transported by a transport device 13 to a fixing device 14, where it is fixed and discharged onto a paper discharge tray 15 as a copy.

In the copying apparatus having the mechanism shown in FIG. 1, both ends of the sheet-like photoreceptor 6 are stretched and fixed on the outer circumferential surface of the rotating drum 5 by means of a mounting plate 16. Various types of this tensioning and fixing mechanism are known. Furthermore, since this is not the gist of the present invention, its explanation will be omitted. The photoreceptor replacement work is normally carried out manually by a user after opening the copying machine top cover 17 provided substantially above the rotating drum and rotating the rotating drum to a desired position.

FIGS. 2 and 3 illustrate in cross section the rotating drum and drive mechanism applied to an electrophotographic copying machine of the type exemplified above, which will be described in detail below. A cylindrical rotating drum 5 having a photoreceptor 6 stretched on its outer peripheral surface by a known method is rotatably supported by a rotating shaft 20 extending in the cylindrical direction through its center. The rotating shaft 20 is supported at one end by a bearing 22 mounted on a frame 21 of the copying machine and at the other end by a bearing 23 mounted on a frame 21' of the copying machine. A pin 2 is attached to one end surface of the rotating drum 5.
The lever 24 with 5 is the mounting screw 2 to the drum.
It is attached so that it can swing around 4a. This pin 25 is connected to a cam surface 26a of a cam plate 26 which is fixed to the rotating shaft 20 and rotated by a known drive source.
The rotating drum is also rotated.

The mechanism for preventing inertial rotation of the drum will be explained with reference to FIG. 2. A hub 19 is fixed to the other end surface of the rotating drum 5, and the outside of the hub 19 has an enlarged head at one end. A sleeve 52 is fixed to the rotating shaft 20. Hub 19 and sleeve 52
A cylinder 51 supported by the ends 19a and 52b of these members is fitted into the outer periphery of the member. A spring 53, which has one end fixed to the sleeve 52 and the other end fixed to the ring 51, is attached to the sleeve 52.
and is wrapped around the hub 19. spring 5
3 refers to a wire with a normal circular cross section or a wire with a rectangular cross section that is tightly wound in a spiral shape around a rotating shaft without any gaps. When turned in the direction of wire winding, the diameter of the spring winding decreases, causing a shape change that tightens the rotating shaft, and when turned in the opposite direction to the wire winding direction, the diameter of the sleeve increases, causing a shape change that loosens the spring. It has the property of occurring. As can be clearly seen from FIG. 4, a locking tooth 51a is formed on the outer periphery of the enlarged head of the ring 51, and a slot 51b is formed at the other end, and as described above, the spring 53 is inserted into this slot 51b.
One end of the two is bent and engaged. On the other hand, a slot 52a is also formed at the other end of the sleeve 52, and as described above, the other end of the spring 53 is bent and engaged with this slot 52a.

Next, the operation of the above mechanism will be explained. Normally, the rotating drum 5 is rotationally driven via a pin 25 pushed by a cam plate 26. At this time, since not only the hub 19 but also the sleeve 52 are rotating together with the rotating drum, the ring 51 is also rotating together with the rotating shaft and the rotating drum. Therefore, the spring 53
9 will never be closed. However, due to its own structural imbalance, the rotating drum 5 tends to rotate ahead of the rotation of the cam plate 26 during rotation, or when the rotating shaft 20 stops, it tends to continue rotating due to inertia. However, at this time, the spring 53 is twisted in the direction of decreasing the radius, and the hub 19
is tightened by this spring 53 and integrally connected to the sleeve 52. In this way, the advance rotation of the rotating drum 5 with respect to the rotating shaft 20 is momentarily suppressed.

The inertial rotation prevention mechanism of the drum, which functioned effectively in this way, becomes a hindrance when replacing the photoconductor.
A mechanism for releasing the mechanism is shown in FIGS. 4 and 5. 4 along with Figures 2 and 5.
The release mechanism according to the present invention will be explained with reference to the drawings.

A pin 27 is installed on the inner surface of the machine frame 21 facing one end surface of the rotating drum 5, and one end of a V-shaped wire spring 28 is wound around the pin 27 several times and hung thereon. The other end of the wire spring 28 is bent into an L-shape to form a hook 28', and the spring is wound about one and a half times in the center to form an engagement hole 28a. One end 2 of a straight wire 29 is provided in this engagement hole 28a.
9' and fold it back, and the other end 29'' hooks and folds back on a locking portion 17' provided on the back surface of the top lid 17 of the main body of the copying apparatus.

In explaining the operation of the release mechanism now, when one copying cycle is completed and the drum rotating shaft 20 stops,
As a result, it is assumed that the rotating drum 5 is integrally connected to the rotating shaft 20 and stopped by the action of the inertial rotation prevention mechanism. In this state, when the upper lid 17 on the top surface of the copying apparatus main body is lifted to replace the photoreceptor on the rotating drum 5, the upper lid 17 is removed from the fourth position.
In the figure, it is opened in the direction of the arrow with point P as the fulcrum. At this time, the locking portion 17' on the back side of the top lid 17
The wire 29, one end of which is locked in the
1a and 51a, the hooking sleeve 51 is rotated counterclockwise. Rotating drum 5 and rotating shaft 20
Since only the sleeve 51 is rotated while the sleeve 51 remains stationary, the spring 53 is biased in a loosening direction, and the rotating drum 5 becomes rotatable with respect to the rotating shaft 20. In other words, the function of the inertial rotation prevention mechanism is canceled.

In this mechanism release operation, since the spring wire 28 and the wire 29 are flexible, the length of the wires 28, 29, the locking position of the wire 29 to the upper cover, or the position between one end of the wire 29 and the engagement hole 28a Regardless of a slight deviation in the engagement position, the hook 28' of the spring wire 28 can be smoothly engaged with the locking tooth 51a. Therefore, manufacturing errors in the lengths of the wires 28 and 29 or the size of the engagement holes, installation errors in the locking portion 17', and the way the operator lifts the top cover 17 have no effect on the release operation. I won't give it. Such an effect can be reliably obtained not only with wire but also with flexible materials such as spring plate materials such as phosphor bronze plates, stainless steel plates, and steel plates, or plastics such as polyacetal and polypropylene.

As described above, according to the present invention, the connection between the rotating drum and the driving member can be severed with a simple configuration, and many effects such as making the device more compact and improving operability can be brought about.

In this embodiment, the drum and drive system are connected using a cam to transmit rotation in one direction, but the mechanism here connects the drum and drive system only when rotating in a predetermined direction; When rotating, the drum may be of any type as long as it can freely rotate, and is not limited to the above method.

Furthermore, the mechanism for preventing inertial rotation of the drum is not limited to that of the embodiment.

[Brief explanation of drawings]

FIG. 1 of the accompanying drawings is a schematic diagram of an electrophotographic copying apparatus to which the present invention is applied, FIG. 2 is a sectional view showing an embodiment of the present invention in the same apparatus, and FIG. 3 is a diagram showing a rotating drum and a drive system. FIG. 4 is a schematic diagram showing an embodiment of a rotating drum drive member release mechanism, and FIG. 5 is a partially cutaway diagram showing an embodiment of the present invention applied to an electrophotographic copying apparatus. FIG. 2 is a perspective view of the copying apparatus shown in FIG. 1... Original table, 2... Irradiation lamp, 3... Reflector, 4... Lens, 5... Rotating drum, 51...
Same cylinder, 51a...locking tooth, 51b, 52a...slot, 52...sleeve, 53...spring, 6...photoreceptor, 7...charging electrode, 8...developing device, 9...paper feed Plate, 10...Feeding roller, 1
DESCRIPTION OF SYMBOLS 1... Paper feed roller, 12... Transfer pole, 13... Conveying device, 14... Fixing device, 15... Paper discharge plate, 1
6...Mounting plate, 17...Top lid, 17'...Locking part,
19...Hub, 20...Rotating shaft, 21...Machine frame,
22, 23... Bearing, 24... Lever, 25, 2
7...Pin, 26...Cam plate, 28...Wire spring, 28'...Hook, 28a...Engagement hole,
29...Wire.

Claims (1)

[Scope of Claims] 1. An electrophotographic copying apparatus comprising a rotatable drum having a photosensitive layer on its surface and a drive member that engages only when rotating in a predetermined direction to rotate the drum. A blocking member that can take a locked state that blocks the displacement when the drum is displaced relative to the driving member and a non-locked state that does not prevent the displacement, and a lid member that can be opened and closed around the drum. . A drive member release mechanism for a rotating drum, characterized in that the blocking member can be switched between a locked state and a non-locked state in conjunction with the opening/closing operation of the lid member. 2. The blocking member is a spring whose one end is fixed to the drive member and wound around the rotating part of the drum, and the other end of the spring is fixed or fixed in conjunction with the opening/closing operation of the lid member. Claim 1, characterized in that the blocking member is switched to a locked state or a non-locked state by forming a free end.
The rotating drum drive member release mechanism described in 2.