Electrophotography – Having particular structure – Modular or displaceable
Utility Patent
2000-03-14
2001-01-02
Grimley, Arthur T. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
C399S105000, C015S256500
Utility Patent
active
06169867
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toner-guiding sheet mounted in a cleaning apparatus for cleaning toner removed from the surface of an image carrying member in an electrophotographic method, a cleaning apparatus for cleaning the surface of an image carrying member, serving as a member to be cleaned, a process cartridge having the cleaning apparatus as at least one process means, and an image forming apparatus having the process cartridge.
2. Description of the Related Art
In general, in an image forming apparatus which uses a rotating-drum-type image carrying member having a photoconductive photosensitive layer on its outer circumferential surface, and which repeats the process of forming an electrostatic latent image on the photosensitive member while rotating the image carrying member, developing the electrostatic latent image using toner, and transferring the obtained toner image onto a transfer material, toner particles and other adhering matter remaining on the surface of the image carrying member are sufficiently removed by a cleaning apparatus after completing one image forming process and before starting the next image forming process. The cleaning apparatus includes a cleaning blade for scraping off toner particles remaining on an image carrying member while contacting the surface of the image carrying member, a toner-guiding sheet which is provided below the cleaning blade in a state of contacting the surface of the image carrying member in order to scoop the scraped toner particles, and a waste-toner reservoir for storing the scraped waste toner particles. The cleaning blade and the toner-guiding sheet are provided so as to contact the surface of the image carrying member. The toner-guiding sheet is mounted at a predetermined position (hereinafter termed a “mounting surface”) of the waste-toner reservoir using a pressure sensitive adhesive double coated tape.
However, since the toner-guiding sheet is made of a monolayer polyethylene terephthalate (PET) film and always contacts the image carrying member, the toner-guiding sheet is subjected to creep deformation so that the distal end of the toner-guiding sheet leaves the image carrying member. Furthermore, since the toner reservoir is formed from a resin material, the mounting surface moves due to a temperature rise of the main body of the apparatus when consecutive image printing operations are performed. As a result of the above-described two types of deformation, when consecutively printing images in a state of a large temperature rise of the main body of the apparatus, there is the possibility that toner particles scraped off by the cleaning blade cannot be assuredly scooped because the distal end of the toner-guiding sheet does not completely contact the image carrying member.
Japanese Patent Laid-Open Application (Kokai) No. 6-195006 (1994) provides a proposal that, after bonding a toner-guiding sheet in a state in which a toner-guiding-sheet bonding surface is curved, the bonded state is released to provide a tension in the longitudinal direction, so that undulation of the distal end of the toner-guiding sheet is prevented, and toner particles scraped off by the cleaning blade can be assuredly scooped because the toner-guiding sheet tightly contacts the surface of the photosensitive member.
However, although the toner-guiding sheet bonded in the above-described manner excellently operates at first, the above-described problem, that the distal end of the toner-guiding sheet is deformed so as to leave the image carrying member when consecutively printing images in a state of a large temperature rise of the main body of the apparatus, is still present. Furthermore, since the distal end of the toner-guiding sheet contacts the surface of the photosensitive member in a state of always being applied with tension in the longitudinal direction, creep deformation of the toner-guiding sheet tends to occur in a shorter time period. Hence, further improvement is desired in order to achieve higher durability.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a toner-guiding sheet in which the above-described problems are solved, a cleaning apparatus having the toner-guiding sheet, a process cartridge having the cleaning apparatus, and an image forming apparatus having the process cartridge.
It is another object of the present invention to provide a toner-guiding sheet whose distal end is made of a material which is hardly subjected to creep deformation, in order to assuredly scoop toner particles, a cleaning apparatus having the toner-guiding sheet, a process cartridge having the cleaning apparatus, and an image forming apparatus having the process cartridge.
It is still another object of the present invention to provide a toner-guiding sheet which can assuredly scoop toner particles a larger number of times even when a temperature rise occurs according to consecutive image forming operations, a cleaning apparatus having the toner-guiding sheet, a process cartridge having the cleaning apparatus, and an image forming apparatus having the process cartridge.
According to one aspect, the present invention that achieves these objectives relates to a toner-guiding sheet for guiding toner removed from an image carrying member. The sheet comprises a free end portion for contacting a surface of the image carrying member, and a fixed-portion, fixable on a fixing member, for fixing the toner-guiding sheet in a state in which the free end portion contacts the image carrying member. The toner-guiding sheet comprises a film having a creep-deformation resisting property such that, when the film, fixed on a fixing member so that a distance &bgr; from a central portion in a longitudinal direction of the fixed portion of the sheet to a central portion in a longitudinal direction of the free end portion of the sheet is substantially 3.86 mm, is brought in contact with a surface of a contact member under conditions such that a distance &agr; from the central portion in the longitudinal direction of the fixed portion of the sheet to a central portion in the longitudinal direction of a contact portion of the free end portion on the surface of the contact member is substantially 1.86 mm, an amount of penetration &dgr; of the central portion in the longitudinal direction of the contact portion of the sheet with respect to the contact member is substantially 2.0 mm, and an amount of charge &xgr; of the central portion in the longitudinal direction of the contact portion with respect to the contact member is substantially 0.74 mm, a change in the amount of penetration &dgr; when leaving the toner-guiding sheet in an environment of a temperature of substantially 45° C./a humidity of substantially 60% RH for substantially 30 days is equal to or less than substantially 0.43 mm.
The toner-guiding sheet also comprises a laminated film having at least a creep-deformation resisting layer between polyester films, a laminated film having at least a creep-deformation resisting layer between polyethylene terephthalate films, or a polyethylene sulfide film. The sheet can have a thickness of substantialy 35-45 &mgr;m. In addition, the toner-guiding sheet is fixed in a state in which a tension is applied at least in the longitudinal direction of the free end portion. Also, the toner-guiding sheet can be fixed in a state in which a tension smaller than the tension applied in the longitudinal direction of the free end portion is applied, or a tension is not applied, in the longitudinal direction of the fixed portion. In addition, the toner-guiding sheet can be fixed in a state in which a tension is applied at least in the longitudinal direction of the free end portion, by fixing the fixing member in a curved state and then releasing the curved state. Further, the toner-guiding sheet is fixed so that the amount of penetration with respect to the image carrying member is larger at the central portion in the longitudinal direction of the image carrying member and the sheet than at two
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grimley Arthur T.
Ngo Hoang
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