Patent US921975A successfully refreshed from Google Patents.
Patent US4688923A successfully refreshed from Google Patents.
← Back to Patent Explorer
US4688923A Expired / Lapsed US ⏱️ 0.0 years remaining

Developing apparatus

Assignee: Toshiba Corp
•
Filing: 1986-02-14
•
Granted: 1987-08-25
•
Expires: 2006-02-14
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A developing apparatus including an electrostatic latent image holder, a developer carrier for carrying a developer and provided opposite to the electrostatic latent image holder and separated therefrom by a predetermined gap, a developing bias voltage applying section for repeatedly applying to the gap between the electrostatic latent image holder and the developer carrier an alternating current voltage having a plurality of different frequencies in order to form an electric field in the gap sufficient for selectively causing the developer to fly and attach to the electrostatic latent image holder, and a control section for variably controlling application periods of the alternating current voltage having the plurality of frequencies by the developing bias voltage applying section while maintaining a predetermined relationship therebetween.

Inventors

  • 👤 Mitsuaki Kohyama

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 11:45
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/065; G03G15/08; G03G15/0806; G03G15/0813

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 119 words
A developing apparatus for applying a developer to an electrostatic latent image, said apparatus comprising: an image-bearing member carrying the electrostatic latent image; a developer carrier carrying a developer thereon, said developer carrier opposing said image-bearing member, with a clearance therebetween to define a developing zone; means for applying an alternating electric field to said developing zone to produce movement of the developer between said image-bearing member and said developer carrier within said developing zone, said alternating electric field having a first frequency in a first application period and a second frequency, different from the first frequency, in a second application period; and means for varying the length of at least one of said first and second application periods.
Claim 2
Dependent Claim 119 words
A developing apparatus for applying a developer to an electrostatic latent image, said apparatus comprising: an image-bearing member carrying the electrostatic latent image; a developer carrier carrying a developer thereon, said developer carrier opposing said image-bearing member, with a clearance therebetween to define a developing zone; means for applying an alternating electric field to said developing zone to produce movement of the developer between said image-bearing member and said developer carrier within said developing zone, said alternating electric field having a first frequency in a first application period and a second frequency, different from the first frequency, in a second application period; and means for varying the length of at least one of said first and second application periods.
Claim 3
Dependent Claim 19 words
An apparatus according to claim 1, further comprising control means comprising means for changing said first and second frequencies.
Claim 4
Dependent Claim 29 words
An apparatus according to claim 1, wherein the clearance defining said developing zone is set to be larger than a thickness of the developer carried by said developer carrier.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-08-24 1991-02-23 1991-08-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-08-24 1995-02-23 1995-08-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-08-24 1999-02-23 1999-08-25 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag