CLEANING UNIT IN ELECTROPHOTOGRAPHIC COPIER

Abstract: A cleaning unit for an electrophotographic copier is provid­ ed to remove toner and developing material from a photo-sensitive material from which a developed image has been transferred and includes a housing (21) having an opening (21a) facing the photo-sensitive material (10a). A main blade member is provided in the housing of the cleaning unit and has an upper portion (22) which abuts against the photo-senstive material through an opening of the housing to scrape the toner and developing materials off the photo-sensitive material. The cleaning unit further includes a receiving blade (23) covering the lower portion of the opening, and having an upper end portion abutted against the photo-sensitive material to allow the toner and developing material scraped off by the main blade to fall into the opening and a film-shaped reinforcing member bonded to the surface of the receiving blade facing the inside of the housing to prevent deformation of the receiving blade.

Description: This invention relates to a cleaning unit in an electrophotographic copier according to the preamble of claim 1. In an electrophotographic copier, a predetermined electrostatic latent image is formed on a photo-sensitive material provided on a rotating photo-sensitive drum. The latent image is then developed with toner, and the developed image is transferred onto a transferring sheet to obtain a copied image. In general, after the developed image has been transferred onto the transferring sheet, the toner and developing materials remain on the photo-sensitive material necessitating removal from the photo-sensitive material with a cleaning unit. A cleaning unit for removing the toner and the developing materials from the photo-sensitive surface of the drum is described in the JP-A-60 170 880. Said cleaning unit is provided with a cleaning member, which abuts against the photosensitive material, and with a receiving blade having an upper end portion abutted against said photosensitive material. This receiving blade being made of several layers, one of which can be considered as a film shaped reinforcing member. Another conventional cleaning unit, such as that shown in Figs. 6, 7, and 8, has a housing 51 with an opening 51a. The opening 51a faces a photo-sensitive material 10a provided on the outer cylindrical wall of a photo-sensitive drum 10. A cleaning member, namely, a main blade 52 is disposed in the upper part of the housing 51 in such a manner as to touch the surface of the photo-sensitive material 10a in order to scrape the remaining toner and developing material off the surface of the photo-sensitive material 10a. A receiving blade 53 of thermo-plastic polyurethane rubber or similar material is provided in such a manner as to cover the lower portion of the opening 51a of the housing 51. The upper edge of the receiving blade 53 abuts against the photo-sensitive material 10a so that all of the toner and developing materials scraped off with the main blade 52 fall positively into the housing 51 without scattering therefrom. If the electrophotographic copier is shipped out of the factory with the upper edge of the receiving blade 53 abutted against the surface of the photo-sensitive material 10a, then the surface of the photo-sensitive material 10a can deteriorate during transportation. The photo-sensitive material 10a is especially sensitive to deterioration when the copier is transported over a long distance with the environmental conditions changing greatly. In order to overcome this difficulty, a method has been employed in which the electrophotographic copier is shipped out of the factory with the receiving blade 53 held away from the photo-sensitive material 10a. For instance, as shown in Fig. 9, the receiving blade 53 is coupled to a support 54 which can be detachably secured to the housing 51 of the cleaning unit, and when the copier is shipped out of the factory, the support 54 is disconnected from the housing 51 (as indicated by the two-dot chain line in Fig. 7). Accordingly, during the transportation of the copier, the receiving blade 53 does not contact the photo-sensitive material 10a and the photo-sensitive material 10a is less likely to be deteriorated. This method is nevertheless disadvantageous because the receiving blade 53 is liable to be deformed. After transportation of the copier, the support 54 is coupled to the housing 51 so that the receiving blade 53 abuts the photo-sensitive 10a. However, the end portion of the receiving blade 53, being abutted against the photo-sensitive material 10a, is bent inwardly of the housing 51, thus forming a gap between the blade and the photo-sensitive material 10a as shown in Fig. 10. If a gap is formed, then when the toner is scrapped off with the main blade, it will drop through the gap, thus smudging the transferring sheet conveying path or some other part of the copier which extends below the housing 51. SUMMARY OF THE INVENTION The object of the invention is to provide a cleaning unit for an electrophotographic copier in which the receiving blade is prevented from being deformed when abutted against the photo-sensitive material. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. Said object of the invention will be solved by the features according to the characterizing portion of claim 1. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention. Fig. 1 is cross-sectional diagram illustrating the electrophotographic copier with a cleaning unit constructed in accordance with the present invention; Fig. 2 is an enlarged sectional view of the cleaning unit shown in Fig. 1; Fig. 3 is an enlarged diagram illustrating the components of the cleaning unit of Fig. 2; Fig. 4 is a perspective view illustrating the components of the cleaning unit of Fig. 2; Fig. 5 is a view taken in the direction of arrrow V-V from Fig. 3; Fig. 6 is a cross-sectional diagram illustrating a conventional cleaning unit; Fig. 7 is an enlarged diagram illustrating the components of the cleaning unit shown in Fig. 6; Fig. 8 is a view taken in the direction of arrow VIII-VIII in Fig. 7; Fig. 9 is a perspective view illustrating the components of the conventional cleaning unit of Fig. 6; and Fig. 10 is a sectional view illustrating a receiving blade in the conventional cleaning unit of Fig. 6. DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings in which like reference characters refer to corresponding elements. A cleaning unit according to the invention is used, for example, in an electrophotographic copier such as shown in Fig. 1. The copier has a photosensitive drum 10 which is turned in the direction of the arrow A, the axis of rotation being located at the center of the drum 10. A photo-sensitive material 10a is provided on the outer cylindrical surface of the photo-sensitive drum 10. While the drum 10 is rotated in the direction of the arrow A, the photo-sensitive material 10a is uniformly charged by a charging unit 11. Then, a predetermined image is projected onto the photo-sensitive material 10a by an exposing unit 12, so that a latent image is formed in the photo-sensitive material 10a. The latent image is developed with toner by a developing unit 13. Then, the developed image is transferred onto a transferring sheet by a transferring unit 14. The transferring sheet is separated from the photo-sensitive material 10a by a separating unit 15. After the developed image is set by a fixing unit 16, the sheet is discharged out of the copier. The toner and other developing materials are then removed from the photo-sensitive material 10 by the cleaning unit 20 according to the present invention. As shown in Fig. 2, the cleaning unit 20 of the present invention includes a housing 21 with an opening 21a; a cleaning member, namely, a main blade 22 for scraping the remaining toner and developing materials off the surface of the photo-sensitive material 10a; a receiving blade 23 for causing the toner and developing materials that are scraped off by receiving blade 23 to drop into the housing 21; and a reinforcing member 24 attached to the receiving blade 23. An opening 21a of the housing 21 is located between the separating unit 15 and the charging unit 11 facing the photo-sensitive material 10a of the photo-sensitive drum 10. The main blade 22 is pivotally supported in the upper portion of the housing 21. More specifically, when the main blade 22 is pivoted in one direction, its end portion 22a protrudes outside the housing through the opening 21a to contact the surface of the photo-sensitive material 10a; and when the main blade 22 is pivoted in the other direction, the end portion 22a is moved away from the photo-sensitive material 10a. The receiving blade 23 is made of thermo-plastic polyurethane rubber or similar material. The receiving blade 23 covers the lower portion of the opening 21a as illustrated more clearly in Fig. 3. The upper end portion of the receiving blade 23 abuts against the photo-sensitive material 10a sustantially over the entire axial length. As shown in Figs. 4 and 5, a reinforcing member 24, of polyester film or similar material, is bonded to the rear surface of the receiving blade 23 facing the inside of the housing 21. The reinforcing member 24 has a cut in its upper end portion facing an image-forming region which is defined on the photo-sensitive material 10a by both end regions in the axial direction. The cut of reinforcing member 24 is arcuate at its corners. Therefore, it is not necessary to bond reinforcing member 24 to the rear surface of the receiving blade 23 which abuts against the image-forming region of the photo-sensitive material 10a. Therefore, the receiving blade 23 is not pushed against the image-forming region of the photo-sensitive material 10a by the reinforcing member 24. Seal members 25 are disposed inside the housing 21 facing the two end portions, or the two non-image-forming regions, of the photo-sensitive material 10a. Each of the seal members 25 is formed by sticking soft fibers on the housing 21. The upper and middle portion of each of the seal members 25 abut against the photo-sensitive material 10a through the opening 21a, and the lower portion of each seal members 25 abuts against the reinforcing member 24. Accordingly, the seal members 25 and the reinforcing member 24 push the receiving blade 23 against the non-image-forming regions of the photo-sensitive material 10a in the axial direction of the photo-sensitive material 10a. Therefore, the toner and other developing materials which are scraped off with the main blade 22 will never be scattered outside of the housing. As shown in Fig. 2, a conveying roller 27 is arranged above a support 26 which is engaged with the housing 21 at the lower end. Therefore, the toner and other developing materials that drop into the housing 21 are conveyed by the conveying roller 27 into a used toner recovering unit 28 which is disposed on the other side of the housing 21 opposite to the side where the photo-sensitive drum 10 is arranged. Before the electrophotographic copier with the cleaning unit of the present invention is shipped out of the factory, a support 26 is removed from the housing 21 so that the receiving blade 23 is held away from the photo-sensitive material 10a. Therefore, before operation of the copier, the support 26 must be engaged with the housing 21 so that the upper end portion of the receiving blade 23 abuts against the photo-sensitive material 10a of the photo-sensitive drum 10. After the support 26 has been coupled to the housing 21, as described above, the copier is operated in the conventional electrophotographing method. That is, a toner image is formed on the photo-sensitive material 10a, and the toner image thus formed is transferred onto a transferring sheet, providing a copied image. As the drum 10 rotates, the part of the photo-sensitive material 10a from which the toner image has been transferred is moved to the cleaning unit 20 according to the present invention. In the cleaning unit 20, the blade 22 abuts against a rotating photo-sensitive material 10a and scrapes the remaining toner and other developing materials off the photo-sensitive material 10a. The toner and other developing materials that are scraped off are allowed to fall down the receiving blade 23, abutted against the photo-sensitive material 10a, into the housing 21. The scraped off material is then conveyed by the conveying roller 27 into the used toner recovering unit 28. In the cleaning unit of the present invention, the reinforcing member 24 is bonded to the receiving blade 23 in the manner described above. Therefore, the cleaning unit overcomes the problem that occurs when the receiving blade abuts against the photo-sensitive material, i.e., deformation of the receiving blade causing a gap to be formed between the receiving blade and the photo-sensitive material. Thus, the toner which is scraped off the photo-sensitive material will not scatter upon dropping through the gap onto the transferring sheet conveying path. It will apparent to those skilled in the art that various modifications and variations can be made in the cleaning unit of the present invention without departing from the scope of the invention as claimed. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims: A cleaning unit in an electrophotographic copier, adapted to remove toner and developing material from a photo-sensitive drum having photo-sensitive material disposed thereon from which a developed image has been transferred, said cleaning unit comprising: a cleaning member (22) having an end portion (22a) which abuts against said photo-sensitive material (10a) to scrape the toner and developing material off said photo-sensitive material (10a), and a receiving blade (23) being made of a plurality of layers having an upper end portion abutted against said photo-sensitive material (10a) to lead off said toner and developing materials scraped off by said cleaning member, characterized in that a housing (21) is provided with an opening (21a) facing said photo-sensitive material; a film-shaped reinforcing member (24) is bonded to the rear surface of said receiving blade (23) facing the inside of said housing (21); and in that said reinforcing member (24) covering the lower portion of the opening (21a) is arranged on the rear surface of the receiving blade (23) at a portion where the receiving blade (23) abuts against a non-image-forming region of the photo-sensitive material (10a). The cleaning unit as claimed in claim 1, wherein said receiving blade (23) to which said reinforcing member (24) has been bonded is detachably coupled to said housing (21). The cleaning unit as claimed in claim 1, wherein said cleaning member is pivotally supported in said housing (21) such that when said cleaning member is pivoted in one direction, said end portion (22a) protrudes outside said housing through said opening (21a) to contact the surface of said photo-sensitive material (10a), and when said cleaning member is pivoted in another direction, said end portion (22a) is moved away from said photo-sensitive material (10a). The cleaning unit as claimed in claim 1, further including a plurality of seal means (25) for pushing said receiving blade (23) against an end portion of said photo-sensitive material (10a) in an axial direction. The cleaning unit as claimed in claim 1, further including a used toner recovering unit means (28), disposed on said housing opposite to said photo-sensitive drum, and a conveying means (27) for carrying the scraped off toner and developing material to said used toner recovering unit means (28). The cleaning unit as claimed in claim 1, wherein said reinforcing member (24) has a cut in its upper end portion at a position facing a portion of said receiving blade (23) where said receiving blade (23) abuts against the image forming region on the photosensitive material (10a).

Inventors: ISHIGURO, YASUYUKI C/O MITA INDUSTRIAL CO. LTD., OGIRI, TADAKAZU C/O MITA INDUSTRIAL CO. LTD.
Applicants: MITA INDUSTRIAL CO. LTD.
Application year: 1987
Main classification: G03G21
IPC codes: G03G21