Claims
- 1. A developing device for developing a latent image electrostatically formed on an image carrier in a developing region to thereby produce a corresponding visible image, said device comprising;
- a rotatable developer carrier for carrying a developer to the developing region, and causing said developer to deposit on the latent image, said developer carrier comprising a conductive base and a resistance body which is made of medium resistance bodies and high resistance bodies arranged on a surface of said conductive base, wherein said medium resistance bodies have a resistivity higher than a resistivity of said conductive base while said high resistance bodies have a resistivity higher than the resistivity of said medium resistance bodies; and
- charging means for forming small closed electric fields in the vicinity of said surface of said developer carrier;
- said developer being deposited on said surface of said developer carrier by said small closed electric fields.
- 2. A developing device as claimed in claim 1, wherein at least said high resistance bodies are charged to selectively deposit a charge thereon to thereby form said small closed electric fields between said high resistance bodies and said medium resistance bodies.
- 3. A developing device as claimed in claim 1, wherein said high resistance bodies and said medium resistance bodies are arranged in a regular pattern.
- 4. A developing device as claimed in claim 1, wherein said high resistance bodies and said medium resistance bodies are arranged in an irregular pattern.
- 5. A developing device as claimed in claim 1, wherein said high resistance bodies have a resistivity of 10.sup.9 to 10.sup.15 .OMEGA.cm, while said medium resistance bodies have a resistivity of 10.sup.3 to 10.sup.8 .OMEGA.cm.
- 6. A developing device for developing a latent image electrostatically formed on an image carrier in a developing region to thereby produce a corresponding visible image, said device comprising;
- a developer carrier for carrying a developer supplied thereto on a surface thereof, conveying said developer to the developing region, and causing said developer to deposit on the latent image; and
- charging means for forming small closed electric fields in the vicinity of said surface of said developer carrier;
- said developer carrier comprising a conductive base, and dielectric bodies fixedly buried in recesses formed in said conductive base;
- said dielectric bodies each having a predetermined cross section, which extends in a direction of a line normal to said surface of said developer carrier.
- 7. A developing device as claimed in claim 6, wherein said surface of said developer carrier has a plurality of surface portions arranged in a predetermined pattern, each of said surface portions having a particular characteristic, and wherein small closed electric fields are formed on said surface portions by depositing a charge on at least one of said surface portions whereby a charged developer is carried on said surface portions by use of said small closed electric fields.
- 8. A developing device as claimed in claim 7, wherein said charge is deposited on said at least one of said surface portions by charging said at least one of said surface portions by means of said charging means.
- 9. A developing device as claimed in claim 8, wherein said dielectric bodies are charged by said charging means to selectively deposit a charge on said surface portions.
- 10. A developing device as claimed in claim 9, wherein said small closed electric fields are formed between said dielectric bodies having a charge and said conductive base.
- 11. A developing device as claimed in claim 8, wherein said conductive base has conductive portions and said dielectric bodies have exposed portions, wherein each of said plurality of surface portions has a particular characteristic comprising said conductive portions of said conductive base and said exposed portions of said dielectric bodies, and wherein at least said exposed portions of said dielectric bodies are charged by said charging means to selectively deposit a charge on said surface portions.
- 12. A developing device as claimed in claim 11, wherein said small closed electric fields are formed between said exposed portions of said dielectric bodies having a charge and said conductive portions of said conductive base.
- 13. A developing device as claimed in claim 11, wherein said conductive portions of said conductive base and said exposed portions of said dielectric bodies are arranged in a regular pattern.
- 14. A developing device as claimed in claim 11, wherein said conductive portions of said conductive base and said exposed portions of said dielectric bodies are arranged in an irregular pattern.
- 15. A developing device an claimed in claim 8, wherein said charging means comprises a developer supply member which contacts said plurality of surface portions to charge said at least one of said surface portions each having a particular characteristic and to supply the developer to said surface portions of said developer carrier.
- 16. A developing device as claimed in claim 15, wherein said charging means frictionally charges said at least one of said surface portions to deposit a charge thereon.
- 17. A developing device as claimed in claim 15, wherein said charging means comprises a frictionally charging roller held in contact with said surface portions of said developer carrier which is located downstream of the developing region and upstream of said developer supply member with respect to an intended direction of developer transport for frictionally charging said at least one of said surface portions of said developer carrier.
- 18. A developing device as claimed in claim 15, wherein said charging means comprises a frictionally charging blade held in contact with said surface portions of said developer carrier which is located downstream of developing region and upstream of said developer supply member with respect to an intended direction of developer transport for frictionally charging said at least one of said surface portions of said developer carrier.
- 19. A developing device as claimed in claim 6, wherein at least a part of said surface of said developer carrier has a charge retaining function and wherein said at least a part of said surface is charged to selectively deposit a charge on said surface to thereby form said small closed electric fields on said surface whereby a charged developer is carried on said surface.
- 20. A developing device as claimed in claim 6, wherein a surface of each of said dielectric bodies has a charge retaining function and wherein said surface of said dielectric body is charged to selectively deposit a charge on said surface to thereby form said small closed electric fields on said surface whereby a charged developer is carrier on said surface.
- 21. A developing device as claimed in claim 6, wherein said predetermined cross-section of said dielectric body is generally V-shaped.
- 22. A developing device an claimed in claim 6, wherein said predetermined cross-section of said dielectric body is generally U-shaped.
- 23. A developing device as claimed in claim 6, wherein said predetermined cross-section of said dielectric body is generally rectangular.
- 24. In a developing device for developing a latent image electrostatically formed on an image carrier by supplying a developer from a developer carrier to a developing region at which said developer carrier faces said image carrier, the improvement wherein said developing device comprises a charging means for charging a photoconductive surface of said developer carrier, and illuminating means for selectively illuminating the photoconductive surface to deposit a charge on said photoconductive surface to produce charged portions and non-charged portions on said photoconductive surface and thereby form a great number of microfields on said photoconductive surface whereby charged developer is carried on said photoconductive surface.
- 25. A developing device as claimed in claim 24, wherein said illuminating means comprises a light source device implemented with a great number of fine point light sources.
- 26. A developing device as claimed in claim 24, wherein said illuminating means comprises an array of a great number of light emitting diodes each being capable of flashing.
- 27. A developing device as claimed in claim 24, wherein said illuminating means comprises a cold cathode tube and a transparent film pattern, wherein light issuing from a light source thereon selectively illuminates the photoconductive surface through openings defined in the transparent film pattern.
Priority Claims (4)
Number |
Date |
Country |
Kind |
1-267763 |
Oct 1989 |
JPX |
|
2-15110 |
Jan 1990 |
JPX |
|
2-84992 |
Apr 1990 |
JPX |
|
2-91088 |
Apr 1990 |
JPX |
|
Parent Case Info
This is a continuation of application Ser. No. 07 /874,216, filed on Apr. 27, 1992, now U.S. Pat. No. 5,315,061, which is a continuation of Ser. No. 07/597,881, filed Oct. 12, 1990, abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (7)
Number |
Date |
Country |
2299669 |
Aug 1976 |
FRX |
0036245 |
Apr 1978 |
JPX |
0211172 |
Dec 1983 |
JPX |
0053973 |
Mar 1985 |
JPX |
0214874 |
Aug 1990 |
JPX |
1385966 |
Feb 1972 |
GBX |
1573375 |
Jun 1977 |
GBX |
Continuations (2)
|
Number |
Date |
Country |
Parent |
874216 |
Apr 1992 |
|
Parent |
597881 |
Oct 1990 |
|