Claims
- 1. A method of developing a latent image formed on a latent image bearing member by latent image forming means, comprising the steps of:
- providing a developer carrying member, movable along an endless path, for carrying a non-magnetic developer for deposit on the latent image bearing member;
- disposing a magnetic member adjacent to a surface of the developer carrying member so as to allow the non-magnetic developer to be fed from a developer container containing a mixture of the non-magnetic developer and magnetic particles while confining the magnetic particles within the container using a magnetic field;
- disposing a gate electrode adjacent to and upstream of the magnetic member with respect to a movement direction of the developer carrying member to control the passage of the developer;
- substantially uniformly applying the non-magnetic developer onto that section of a surface of the developer carrying member which corresponds to a section of the latent image bearing member to be developed and directly and substantially uniformly preventing the application of the developer onto that section of the surface of the developer carrying member which corresponds to a section of the latent image bearing member not to be developed by operation of the gate electrode; and
- developing the latent image on the latent image bearing member with the developer carrying member carrying the thus applied developer so as to prevent the developer from being deposited on the latent image bearing member at the non-development section.
- 2. A method according to claim 1, wherein said applying step and said preventing step occur alternately with movement of the developer carrying member.
- 3. A method according to claim 1, wherein said applying step and said preventing step occur substantially simultaneously at longitudinally different portions on the developer carrying member.
- 4. A method according to claim 3, wherein said development section is determined in accordance with the size of a transfer material to which the developed image is transferred.
- 5. A method according to claim 1, wherein in said developing step, an alternating electric field is formed between the latent image bearing member and the developer carrying member for moving the developer therebetween.
- 6. A method according to claim 1, wherein in said developing step, an alternating electric field is formed between the latent image bearing member and the developer carrying member for moving the developer therebetween, and wherein the developed image is transferred onto a transfer material.
- 7. A method according to any one of claims 1 to 6, wherein said applying step is effected by applying to the gate electrode a voltage of a polarity the same as that of the developer, wherein said preventing step is effected by applying to the gate electrode a voltage of a polarity opposite to that of the developer, and wherein the polarity of the applied voltage is controlled in accordance with the boundary between the development section and the non-development section.
- 8. A method according to claim 7, wherein said magnetic field is formed by providing the magnetic member adjacent the outlet of the developer container and a stationary magnetic field producing means 5-50 degrees upstream of the confining member with respect to the movement direction of the developer carrying member.
- 9. A method of developing a latent image formed on a latent image bearing member by latent image forming means, comprising the steps of;
- providing a first developing carrying member, movable along an endless path, for carrying a first non-magnetic developer for deposit on the latent image bearing member;
- disposing a first magnetic member adjacent to a surface of the first developer carrying member so as to allow the first developer to be fed from a first developer container containing a mixture of the first non-magnetic developer and magnetic particles while confining the magnetic particles within the first container using a magnetic field;
- disposing a first gate electrode adjacent to and upstream of the first magnetic member with respect to a movement direction of the first developer carrying member to control passage of the first developer;
- substantially uniformly applying the first developer onto that section of a surface of the first developer carrying member which corresponds to a first development section of the latent image bearing member to be developed and directly and substantially uniformly preventing the application of the first developer onto that section of the surface of the first developer carrying member which corresponds to a first non-development section of the latent image bearing member not to be developed by operation of the first gate electrode;
- developing the latent image on the latent image bearing member with the first developer carrying member carrying the thus applied first developer so as to prevent the first developer from being deposited on the latent image bearing member at the first non-development section;
- providing a second developer carrying member, movable along an endless path, for carrying a second non-magnetic developer for deposit on the latent image bearing member;
- disposing a second magnetic member adjacent to a surface of the second developer carrying member so as to allow the non-magnetic developer to be fed from a second developer container containing a mixture of the second non-magnetic developer and magnetic particles while confining the magnetic particles within the second container using a magnetic field;
- disposing a second gate electrode adjacent to and upstream of the second magnetic member with respect to a movement direction of the second developer carrying member to control passage of the second developer;
- substantially uniformly applying the second developer onto that section of a surface of the second developer carrying member which corresponds to a second development section of the latent image bearing member and directly and substantially uniformly preventing the application of the second developer onto that section of the surface of the second developer carrying member which corresponds to a second non-development section of the latent image bearing member not to be developed by operation of the second gate electrode; and
- developing the latent image on the latent image bearing member with the second developer carrying member carrying the thus applied second developer so as to prevent the second developer from being deposited on the latent image bearing member at the second non-development section.
- 10. A method according to claim 9, wherein the first development section and the second development section are different, and wherein the first developer and the second developer are different.
- 11. A method according to claim 9, wherein the first developer and the second developer are different in color, and the sections developed by said two developing steps are simultaneously transferred onto a transfer material.
- 12. A method according to any one of claims 9 to 11, wherein each applying step is effected by applying to the associated gate electrode a voltage of a polarity the same as that of the developer in the associated container, wherein each preventing step is effected by applying to the associated gate electrode a voltage of a polarity opposite to that of the developer in the associated container, and wherein the polarity of such voltage is controlled in accordance with the boundary between the associated development and non-development sections.
- 13. A method according to claim 12, wherein each magnetic field is formed by providing the associated magnetic member adjacent the outlet of the associated container and a stationary magnetic field producing means 5-50 degrees upstream of the magnetic member with respect to the movement direction of the associated developer carrying member.
- 14. An apparatus for developing a latent image formed on a latent image bearing member by latent image forming means, comprising:
- a developer carrying member, movable along an endless path, for carrying a non-magnetic developer for deposit on the latent image bearing member;
- a developer container for containing the developer;
- means for applying the developer onto a surface of the developer carrying member, said applying means including a magnetic member disposed adjacent to a surface of said developer carrying member so as to allow the non-magnetic developer to be fed from a developer container containing a mixture of the non-magnetic developer and magnetic particles while confining the magnetic particles within the container using a magnetic field and a gate electrode disposed adjacent to and upstream of said magnetic member with respect to a movement direction of said developer carrying member to control the passage of the developer;
- control means for controlling said gate electrode to apply substantially uniformly the developer onto that section of the surface of said developer carrying member which corresponds to a section of the latent image bearing member to be developed, but to directly prevent substantially uniform application of the developer onto that section of the surface of said developer carrying member which corresponds to a section of the latent image bearing member not to be developed; and
- means for effecting development of the latent image on said latent image bearing member with said developer carrying member carrying the thus applied developer.
- 15. An apparatus according to claim 14, wherein said development section is interposed between the non-development section in the direction of movement of said developer carrying member.
- 16. An apparatus according to claim 14, wherein the non-development section is adjacent to the development section, in the longitudinal direction of said developer carrying member.
- 17. An apparatus according to claim 16, wherein said development section corresponds to the size of a transfer material to which the developed image is transferred.
- 18. An apparatus according to claim 14, wherein said gate electrode includes a plurality of electrodes to which a voltage is supplied, the voltage being selectively the same as or opposite to a polarity of the developer which is electronically charged when mixed with the magnetic particles, and wherein the voltage of the same polarity is applied when the developer is to be applied to the surface, and the opposite polarity is applied when the developer application is to be prevented.
- 19. An apparatus according to claim 18, wherein said magnetic member is adjacent an outlet of said container, said apparatus further comprising magnetic field generating means disposed across said developer carrying member from said magnetic member and upstream of said magnetic member with respect to the movement direction of said developer carrying member.
- 20. An apparatus according to claim 14, wherein said developer carrying member, developer container, applying means and developing means form a first developing unit utilizing a first developer, and wherein said apparatus further comprises another developer carrying member, developer container, applying means and developing means forming a second developement unit utilizing a second developer.
- 21. An apparatus according to claim 14, wherein the surface of said developer carrying member is an insulating layer having 10.sup.7 -10.sup.12 ohm.cm resistance.
Priority Claims (1)
Number |
Date |
Country |
Kind |
58-108078 |
Jun 1983 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 619,113 filed June 11, 1984, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (1)
Number |
Date |
Country |
49-130844 |
Nov 1974 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
619113 |
Jun 1984 |
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