Apparatus for minimizing toner contamination on an image formation member
AssigneeRicoh Company, Ltd.
InventorsTakatsugu Fujishiro, Masami Hiramatsu, Masumi Sato, Hitoshi Ishibashi, Hiroshi Yosinaga, Yukiko Iwasaki
Life of this patent
Estimating the term…
Abstract
To prevent deterioration of charge performance, which is caused by wear of a gap control member that keeps a charge roller into non-contact with the image carrier, the charge roller is brought into contact with a surface of a photosensitive drum via a pair of tape members as the gap control member that contacts with a coat and non-charge portion of the photosensitive drum. A gap G can be formed between an effective charge width portion of the charge roller and the surface of the photosensitive drum.
Claims26
An image forming apparatus, comprising:
- an image carrier configured to include a coat portion configured to form a photosensitive layer and a pair of non-coat portions at both sides thereof, said non-coat portion being formed of a material harder than said coat portion;
- a charge member configured to charge the coat-portion;
- and
- a gap control member configured to contact with a non-charged area of the coat portion;
- wherein said charge member is brought into contact with a surface of the image carrier via the gap control member to form a prescribed gap between the charge member and the surface of the image carrier along with an effective charge width of the charge member.
The image forming apparatus, comprising:
- an image carrier configured to include a coat portion, a non-coat portion and a photosensitive layer;
- a charge member configured to charge the coat portion of the image carrier;
- a gap control member configured to contact the coat portion of the image carrier, and disposed for forming a gap between the charge member and the image carrier by contacting with a non-charged area;
- and
- a cleaning member configured to clean the surface of the image carrier over a prescribed cleaning width by coming into sliding contact therewith, wherein said gap control member is position within the prescribed cleaning width.
An image forming apparatus, comprising:
- a charge member arranged to form at least a prescribed gap between its image forming area and a non-coat portion of a surface of an image carrier;
- and
- a charge unit configured to charge a coat portion of the surface of the image carrier by impressing a voltage between the charge member and the image carrier;
- wherein:
- the following relationship is established when the flatness of the surface of the image carrier is A, that of said charge member facing the image carrier is B, and the prescribed gap is C:
- A+B<C.
An image forming apparatus, comprising:
- a roller-shaped charge member configured to form a prescribed gap in an image forming area between the charge member and the image carrier by bringing the charge member into contact with a non-coat portion of a surface of a cylindrical image carrier via a butt-contact member arranged outside the image forming area;
- and
- a charge unit configured to charge a coat portion of the surface of the image carrier by impressing a voltage between the charge member and the image carrier;
- wherein the following relationship is established when the axial straightness of the surface of the image carrier is D, that of the roller surface of the charge member is E, and the prescribed gap is C:
- D+E<C.
An image forming apparatus, comprising:
- image bearing means for bearing an image, said image bearing means including a coat portion as a photosensitive layer and a pair of non-coat portions at both sides thereof;
- charging means for charging the coat portion;
- and
- gap controlling means for contacting with a non-charged area of the coat portion;
- wherein said charging means are brought into contact with a surface of the image bearing means via the gap controlling means so as to form a prescribed gap between the charging means and the surface of the image bearing means along with an effective charge width of the charging means.
Dependencies are inferred from the claim text.