US 3672764 A
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June 27, 1972 K. HARTWIG ETAL 3,672,764
ELECTROSTATIC COPIER WITH REMOVABLE CLEANING MODULE Filed Dec. 2; 1970 INVENTOR KARL HARTWIG HERBERT ENGEL BY GUNTER SCHNALL All! hul United States Patent O 3,672,764 ELECTROSTATIC COPIER WITH REMOVABLE CLEANING MODULE Karl Hartwig, Unterhacliing, and Herbert Eugel and Gunther Schnall, Munich, Germany, assignors to Agfa- Gevaert Akfiengesellschaft, Leverkusen, Germany Filed Dec. 2, 1970, Ser. No. 94,422 Claims priority, application Germany, Dec. 4, 1969, P 19 60 800.5 Int. Cl. G03g 15/00 US. Cl. 355-15 9 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates generally to copying apparatus, and more particularly to an electrostatic copier. Still more specifically the present invention relates to an electrostatic copier having cleaning means for cleaning surface contaminants from the photoconductive layer of the device.
In electrostatic copiers a photoconductive layer is provided, usually on the outer surface of a rotatable drum, and in such devices residual quantities of the toner powder used in making photostatic copies by the electrostatic process, tend to adhere. This contamination is undesirable as is well known in the art, and for this reason devices have been developed for effecting a cleaning of the photoconductive layer. This involves usually the provision of a cleaning tape or ribbon, usually made of paper, which can be brought into contact with the surface of the travelling layer and which frictionally removes the adhering residual toner. The problem with these prior-art constructions is that they are quite complicated, and in particular it is diflicult to remove and install the cleaning tape. Evidently, when the cleaning tape has become contaminated over its entire length, then it must be removed and it is undesirable that this should be a ditflicult and time-consuming process considering the effort which has gone into developing electrostatic copiers with a view to make the production of copies simple and speedy.
SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to overcome the aforementioned disadvantages.
More particularly it is an object of the present invention to provide, in an electrostatic copier, an arrangement for facilitating the rapid and simple installation and removal of the cleaning tape.
A concomitant object of the invention is to provide such an arrangement which is simple in its construction and reliable in its operation, and which can be produced in inexpensively.
In pursuance of the above objects, and others which will become apparent hereafter, one feature of the invention resides, in an electrostatic copier, in the provision of a combination including support means, a travelling photoconductive layer, and a cleaning module which is con- Patented June 27, 1972 nectable with and disconnectable from the support means in toto. The cleaning module comprises a pay-off roller and a take-up roller, a cleaning tape which is convoluted about the rollers, biasing means biasing increments of the cleaning tape into contact with the travelling layer for frictional removal of surface contaminants, and advancing means for incrementally advancing the tape from the payoff roller to the take-up roller.
It is the gist of the present invention that the cleaning module including the aforementioned components, can be connected with and disconnected from the support in toto, as pointed out before, that is that all components are removed or installed at once. Insofar as the advancing means is concerned it is advantageous if this comprises a gear which is provided on the cleaning module on cooperates with the advancing roller for advancing the same, and which meshes-when the cleaning module is connected with the support means-with a driven gear provided on the support means itself and so positioned as to necessarily move into meshing engagement with the gear on the module when the latter is in connected position.
By resorting to the present invention a removal of the cleaning module in toto from the support means makes the cleaning tape freely accessible for installation or removal. This greatly facilitates these steps. Furthermore, no actuating or other components are provided on the support means itself for cooperation with the biasing means and with the drive of the cleaning tape. Other than the driven gear mentioned above. The coupling with this gear takes place in a very simple manner simply as a result of a connection of the cleaning module in toto with the support means.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING The single figure is a somewhat diagrammatic vertical section through a portion of an electrostatic copier embodying the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing now specifically, it will be seen that reference numeral 1 diagrammatically illustrates a support means of an electrostatic copier. No details of the support means are shown because they can be entirely conventional and are of no consequence for the purposes of the present invention, as long as the cleaning module according to the present invention can be connected with and disconnected from the support means in toto.
Similarly, a copying drum 2 is mounted for rotation in the support means 1 and turns in the direction of the arrow A. This is also conventional, as is the fact that the outer circumferential surface of the drum 2 is provided with the diagrammatically illustrated photoconductive layer 2a. Finally, the support means 1 is further provided with guide portions 3 and 4 which guide the movement of the cleaning module 5 during its connection or disconnection from the support means 1.
The cleaning module 5 is a self-contained unit, as the term module already implies, and has peripheral Walls one of which is provided with an upwardly open upright slot 5a into which a part of the shaft 6 of a pay-01f roller 7 can be inserted from above. Another slot 5b provided in the same wall but spaced from the slot 5a, is downwardly open and permits insertion of the shaft 9 of a take-up roller 10. A cleaning tape or ribbon 8, which may in conventional manner consist of a felt-like (e.g. expendable) paper web or the like, is convoluted about the two rollers, being supplied in form of a coil 7a on the pay-off roller 7 and being windable onto the tape-up roller 10.
The drawing shows clearly that the shaft 9 of the roller 10 would ordinarily have a tendency to fall out of the slot 517. For this reason it is retained in this slot by means of a latch arm 11 which is pivoted on a pivot 12 and which is biased by a tension spring 14 one end of which is connected to the arm 11 and the other end of which is connected to a pin 13 provided on the support means 1 and with which this end of the spring 14 is engaged when the module is connected with the support means 1 in the manner illustrated.
The advancing means for incremental advancement of the tape 8 from the pay-off roller 7 onto the tape-up roller comprises a gear 15 which is fast with the shaft 9 of the take-up roller 10, and which meshes with a driven gear 16 provided on the support means 1 and so positioned that when the cleaning module 5 is connected with the support means 1 by moving along the guide portions 3 and 4, the gears 15 and 16 will move to a position in which they can mesh.
The module 5 further comprises an arm 18 which is pivoted on a pivot 17 and connected with one end of a tension spring 19 the other end of which is hooked over a nose or projection 50 on the walls or housing of the module 5. A shaft 20 carried on the arm 18 journals the pressure roller 21 for rotation, and the pressure roller 21 biases increments of the cleaning tape 8-which is trained about the pressure roller 21 in the manner illustrated-into frictional contact with the photoconductive layer -2a so that, when the latter travels upon rotation of the drum 2, adhering toner residues are frictionally removed from the layer 2a. The cleaning tape 8 is further trained about guide rollers 22 and 23 and is maintained taut by providing a friction device which is inserted into the drive of the take-up roller 10 and a brake which is associated with the pay-off roller 7.
It is advantageous for the gear 16 to be driven from the drive of the copier itself, that is from the drive which rotates the drum 2 in the direction of the roller A, with a step-down gearing being interposed between them in order to assure that the gear 16 turns very slowly so that new increments of the tape 8 are slowly brought into contact with the layer 2a as the tape 8 is gradually unwound from the pay-off roller 7 and wound onto the takeup roller 10.
The cleaning module 5 must of course be releasably connected with the support means. For this purpose the module 5 has a'shaft 24 on which an arm 25 is pivoted which is provided with a grip 25a located exteriorly and accessible to an operator when the module 5 is connected with the support means 1 in the manner illustrated. A cam follower pin 26 is mounted on the arm 25 and moves in an arcuate path when the arm is pivoted about the shaft 24. It abuts against a cam track 27 provided on the support means 1 itself, and it is pointed out that the radius of curvature of the curved cam track 27 is somewhat smaller than the radius of curvature of the arcuate path through which the follower pin 26 moves when the arm 25 is pivoted about the shaft 24. The lower end position of the arm 25 is illustrated in broken lines and the arm 25 will be moved to this position when the module 5 is to be disconnected from the support means. On the other hand, when the module has been inserted in the manner illustrated and is to be releasably connected with the support means 1, the arm 25 is pivoted from the broken-line end position into its upper full-line end position. In so doing, the follower pin 26 engages and moves along the cam track 27; as a result of this the entire module 5 is shifted somewhat in the direction of the arrow b which causes the pressure roller 21 and thereby the increment of the cleaning tape 8 which is trained about it, to engage the photoconductive layer 2 in opposition to the urging of the spring 19. At the same time the gears 15 and 16 move into mesh with one another. As this movement in the direction B takes place, the follower pin 26 moveswith reference to the displacement in the direction of the arrow Bpast a dead-center location so that when the arm 25 is in its upper full-line position, it will be retained in this position by the efiect of the spring 19.
Conversely, when it is desired to disconnect the module 5 from the support means 1, the arm 25 is pivoted to its broken-line lower end position by engagement with the exposed handle or grip 25a. This causes the pressure of the roller 21 against the drum 2 to be terminated, and at the same time the gears 15 and 16 move out of mesh. The follower pin 26 moves out of engagement with the cam track 27 and now the module 5 can be withdrawn from the support means 1 by means of the handle 28; Once this is done, the rollers 7 and 10 are freely accessible for removal of the soiled cleaning tape and for insertion of a new one.
In this manner the present invention greatly facilitates the replacement of soiled cleaning tapes with new ones and thus brings the ease of execution of this important maintenance function into line with the ease of operation of the electrostatic copying device as a whole.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in an electrostatic copier, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:
1. In an electrostatic copier, in combination, support means; a travelling photoconductive layer; a cleaning module connectable with and disconnectable from said support means in toto, said cleaning module comprising a pay-off roller and a take-up roller, a cleaning tape convoluted about said rollers, biasing means biasing increments of said cleaning tape into contact with the travelling layer for frictional removal of surface contaminants, and advancing means including a passive gear on said module for incrementally advancing said tape from said payoff roller to said take-up roller; and a driven gear on said support means positioned for meshing with said passive gear in response to connection of said module with said support means.
2. In a copier as defined in claim 1, said biasing means comprising a spring-loaded pressure roller urging said increments of said tape into contact with said layer.
3. In a copier as defined in claim 1; further comprising releasable arresting means operative for arresting said module in response to connection of the same with said support means.
4. In a copier as defined in claim 3; and release means accessible exteriorly of said copier to an operator, for releasing said arresting means preparatory for disconnection of said module from said support means.
5. In a copier as defined in claim 1, wherein said tape is an expendable paper web.
6. In an electrostatic copier, in combination, support means; a travelling photoconductive layer; a cleaning module connectable with and disconnectable from said support means in toto, said cleaning module comprising a pay-off roller and a take-up roller, a cleaning tape convoluted about said rollers, biasing means biasing increments of said cleaning tape into contact with the travelling layer for frictional removal of surface contaminants, and advancing means for incrementally advancing said tape from said pay-off roller to said take-up roller; and releasable arresting means for arresting said module in response to connection of the same with said support means, including cooperating cam and follower means on said module and support means and operative for displacing said module in direction towards said layer through a predetermined distance preliminary to arresting of said module.
7. In an electrostatic copier, in combination, support means; a travelling photoconductive layer; a cleaning module connectable with and disconnectable from said support means in toto, said cleaning module comprising a pay-off roller and a take-up roller, a cleaning tape convoluted about said rollers, biasing means biasing increments of said cleaning tape into contact with the travelling layer for frictional removal of surface contaminants, and advancing means for incrementally advancing said tape from said pay-off roller to said take-up roller; and re leasable arresting means for arresting said module in response to connection of the same with said support means, including a cam on said support means having a cam track with a predetermined radius of curvature, an arm pivotably mounted on said module, a cam follower engageable with said cam track and positioned for moving during pivoting of said arm in an arcuate path whose radius of curvature is slightly greater than that of said cam track, and a gripping portion on said arm accessible at the exterior of said copier to an operator for effecting pivoting of said arm.
8. In a copier as defined in claim 7, said cam follower being a pin mounted on said arm.
9. In a copier as defined in claim 7, said cam follower being mounted on said arm so as to move to and past a dead-center position in response to movement of said arm in a sense engaging said cam follower with said cam track for arresting said module.
References Cited UNITED STATES PATENTS 3,099,856 8/1963 Eichorn et a1. 35515 X 3,190,198 6/1965 Eichorn 355l5 SAMUEL S. MATTHEWS, Primary Examiner R. L. MOSES, Assistant Examiner US. Cl. X.R. l5256.52; 355-3