Developing apparatus for electrostatic image
AssigneeCanon Kabushiki Kaisha
InventorsNagao Hosono, Koichi Kinoshita, Toru Takahashi
Life of this patent
Estimating the term…
Abstract
A developing device for electrophotography includes a developer supporter faced to an image bearing member with a constant space maintained therebetween at a developing station, a developer supply and an elastic developer limiting member maintained in predetermined pressure contact with the developer supporter between the developer supply and the developing station to limit the thickness of developer supported on the supporter to a value not causing contact of the developer with the non-imaged area on the image bearing member.
Claims50
[1. A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in facing relationship with an image carrying means in a developing station for developing a latent image carried on the image carrying means, said supporting member being separated from the image carrying means by a predetermined distance;
- means for supplying powder developer to said supporting member;
- and an elastic developer limiting member having a free end upstream of the developing station, with respect to the direction of movement of the developer, which is maintained in predetermined pressure contact with said developer supporting member at a position between said developer supply means and the developing station.]
[2. An apparatus according to claim 1, wherein said elastic limiting member has a hardness of 70 degrees and applies a pressure of between 0.4 and 40 grams per centimeter.]
[3. A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in a developing station in facing relationship with the surface of an image carrying member and separated therefrom by a predetermined distance;
- means for supplying powder developer to said movable developer supporting member;
- a first developer layer limiting member provided between said supply means and the developing station and separated from said developer supporting member by a predetermined distance;
- and
- a second developer layer limiting member provided between said first limiting member and the developing station, said second limiting member being composed of elastic material and having a free end system of the developing station, with respect to the direction of movement of the developer, maintained in predetermined pressure contact with said developer supporting member.]
[4. A developing apparatus according to claim 3, wherein said first limiting member is a rigid member.]
[5. A developing apparatus for developing with powder developer, comprising:
- a movable developer supporting member provided in a developing station in facing relationship with the surface of an image carrying member and separated therefrom by a predetermined distance;
- means for generating a magnetic field in the developing station;
- magnetic developer supply means for supplying magnetic powder developer to said developer supporting member;
- and
- an elastic developer layer limiting member provided at a position between said developer supply means and the developing station and having a free end upstream of the developing station, with respect to the direction of movement of the developer, maintained in predetermined pressure contact with said developer supporting member.]
[6. A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in a developing station in facing relationship with the surface of an image carrying member and separated therefrom by a predetermined distance;
- magnetic developer supply means for supplying magnetic powder developer to said developer supporting member;
- and
- an elastic developer limiting member provided at a position between said developer supply means and the developing station and having a free end upstream of the developing station, with respect to the direction of movement of the magnetic developer maintained in predetermined pressure contact with said developer supporting member.]
[7. A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in a developing station in facing relationship with the surface of an image carrying member and separated therefrom by a predetermined distance;
- means for generating a magnetic field in the developing station;
- magnetic developer supply means for supplying magnetic powder developer to said developer supporting member;
- an elastic developer limiting member at a position between said developer supply means and the developing station and having a free end system of the developing station, with respect to the direction of movement of the magnetic developer, maintained in predetermined pressure contact with said developer supporting means;
- and
- means for generating a magnetic field where said elastic limiting member is in contact with said developer supporting member.]
[8. A developing apparatus according to claim 7, wherein said means for generating a magnetic field in the developing station and said means for generating a magnetic field where said elastic limiting member is in contact with said developer supporting member are composed of the same magnet.]
[9. A developing apparatus according to claim 7, wherein said elastic limiting member is a rubber plate.]
[10. A developing apparatus according to claim 9, wherein said rubber limiting plate is maintained in pressure contact in the forward direction with respect to the moving direction of said developer supporting member.]
[11. A developing apparatus according to claim 9, wherein said rubber limiting plate is maintained in pressure contact in the reverse direction with respect to the moving direction of said developer supporting member.]
[12. A dry developing apparatus for developing latent images, comprising:
- developer supporting means upon which dry developer may be moved to a developing zone at which said developer supporting means faces a latent image carrying member;
- means for supplying dry developer to said developer supporting means;
- and
- an elastic thickness limiting member having a free end upstream of the developing zone, with respect to the direction of movement of the developer, which bears on said developer supporting means between the position where developer is supplied onto said developer supporting means and the developing zone, so as to limit the thickness of the developer layer which moves on said developer support means toward the developing zone.]
[13. A developing apparatus according to claim 12, wherein said developer supporting means comprises a member arranged for movement to carry the developer to the developing zone.]
[14. A developing apparatus according to any one of claims 12 or 13, including a further thickness limiting member which is positioned upstream of said elastic thickness limiting member with respect to the direction of movement of the developer so as to limit the thickness of the developer layer moving toward the elastic thickness limiting member and which is separated from the surface of said developer supporting means carrying the developer.]
[15. A developing apparatus according to claim 14, wherein said first thickness limiting member is a rigid member.]
[16. A developing apparatus according to claim 14, including a magnet member for producing magnetic fields in the developing zone and in the regions of each of said thickness limiting members.]
[17. A developing apparatus according to claim 13, wherein said developer supporting means comprises a cylindrical sleeve, said supplying means being arranged to supply developer onto the peripheral surface of said sleeve.]
[18. A developing apparatus according to claim 17, wherein said sleeve is rotatable about its longitudinal axis to cause movement of the developer.]
[19. A developing apparatus according to claim 13, wherein said developer supporting means comprises an endless belt arranged to rotate about a plurality of rollers.]
[20. A developing apparatus according to claim 12, including means for producing a magnetic field at the developing zone.]
[21. A developing apparatus according to claim 12, including means for producing a magnetic field in the region of contact between said elastic thickness limiting member and said developer supporting means.]
[22. A developing apparatus according to claim 12, including a magnet member which produces a magnetic field at both the developing zone and in the region of contact between said elastic thickness limiting member and the developer support means.]
[23. A developing apparatus according to claim 22, wherein said magnet member is stationary so that said magnetic fields produced thereby are stationary.]
[24. A developing apparatus according to claim 22, wherein said magnet member is movable to cause movement of said magnetic fields.]
[25. A developing apparatus according to claim 12, wherein said elastic thickness limiting member is in the form of a resilient plate.]
[26. A developing apparatus according to claim 25, wherein said resilient plate is arranged with a gap between it and said developer supporting means tapering toward the region of pressure contact in the direction of movement of the developer.]
[27. A developing resilient plate is arranged with a gap between it and said developer supporting means tapering toward the region of pressure contact in a direction opposite to the direction of movement of the developer.]
[28. A developing apparatus according to claim 12, wherein said elastic thickness limiting member is a roller.]
[29. A developing apparatus according to claim 12, wherein at the developing zone the gap between said developer supporting means and the latent image carrying member is such as to avoid contact between the developer supported on said developer supporting means and the portion of the latent image on the latent image carrying member which is not to be developed.]
[30. A developing apparatus according to claim 12, including means for vibrating said elastic thickness limiting member to cause said thickness limiting member to oscillate in a direction transverse to the direction of movement of the developer, thereby to avoid the coagulation of developer between said developer supporting means and said thickness limiting member.]
A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in facing relationship with a image carrying means in a developing station for developing a latent image carried on the image carrying means, said supporting member being separated from the image carrying means by a predetermined distance;
- means for supplying powder developer to said supporting member;
- and
- an elastic developer limiting member having a free end upstream of the developing station, with respect to the direction of movement of the developer, which is maintained in predetermined pressure contact with said developer supporting member at a position between said developer supply means and the developing station to regulate a thickness of a layer of the developer particles supplied by said supplying means, wherein said limiting member includes an elastic plate having a surface including a contact portion which is in surface press-contact with said developer supporting member counter-directionally with respect to a movement direction of the developer supporting member, and an extension surface portion which extends toward the downstream direction from the contact portion and which is faced to said developer supporting member, wherein said plate and said developer supporting member cooperate to form a nip, in the contact portion, through which the developer particles are passed so that the thickness of the developer layer is regulated, and wherein the elastic plate has an end portion in the developer particles.
A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in facing relationship with an image carrying means in a developing station for developing a latent image carried on the image carrying means, said supporting member being separated from the image carrying means by a predetermined distance;
- means for supplying powder developer to said supporting member;
- and
- an elastic developer limiting member having a free end upstream of the developing station, with respect to the direction of movement of the developer, which is maintained in predetermined pressure contact with said developer supporting member at a position between said developer supply means and the developing station to regulate the thickness of a layer of the developer particles supplied by said supplying means, wherein said limiting member includes a plate having rubber elasticity, wherein the plate has a surface including a contact portion which is in surface press-contact with said developer supporting member counter-directionally with respect to a movement direction of the developer supporting member, and an extension surface portion which extends toward the downstream direction from the contact portion and which is faced to said developer supporting member, and wherein said plate and said developer supporting member cooperate to form a nip, in the contact portion, through which the developer particles are passed so that the thickness of the developer layer is regulated.
A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in facing relationship with an image carrying means in a developing station for developing a latent image carried on the image carrying means, said supporting member being separated from the image carrying means by a predetermined distance;
- means for supplying powder developer to said supporting member;
- and
- an elastic developer limiting member having a free end upstream of the developing station, with respect to the direction of movement of the developer, which is maintained in predetermined pressure contact with said developer supporting member at a position between said developer supply means and the developing station wherein said limiting member is an electrically conductive and elastic plate having a surface including a contact portion which is in surface press-contact with said developer supporting member co-directionally with respect to a movement direction of the developer supporting member, and an extension surface portion which extends toward the upstream direction from the contact portion and which is faced to said developer supporting member, and wherein said plate and said developer supporting member cooperate to form a nip, in the contact portion, through which the developer particles are passed so that the
- thickness of the developer layer is regulated.
A developing apparatus for developing with a powder developer, comprising:
- a movable developer supporting member provided in facing relationship with an image carrying means in a developing station for developing a latent image carried on the image carrying means, said supporting member being separated from the image carrying means, by a predetermined distance;
- means for supplying powder developer to said supporting member;
- and
- an elastic developer limiting member having a free end upstream of the developing station, with respect to the direction of movement of the developer, which is maintained in predetermined pressure contact with said developer supporting member at a position between said developer supply means and the developing station wherein said limiting member is an electrically conductive and elastic plate having a surface including a contact portion which is in surface press-contact with said developer supporting member counter-directionally with respect to a movement direction of the developer supporting member, and an extension surface portion which extends toward the downstream direction from the contact portion and which is faced to said developer supporting member, and wherein said plate and said developer supporting member cooperate to form a nip, in the contact portion, through which the developer particles are passed so that the thickness of the developer layer is regulated.
Dependencies are inferred from the claim text.