US4118710A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic printing apparatus comprising improved printing electrode head
Assignee: Ricoh Co Ltd
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Filing: 1976-12-20
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Granted: 1978-10-03
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Expires: 1996-12-20
Abstract
Abstract Liquid or dry developing substance comprising charged particles is applied to a base electrode in the form of a rotary cylinder. A sheet of recording paper is fed in contact with the cylinder. A printing head comprises at least one bias electrode to which is applied a bias voltage of a polarity to repel the charged particles against the cylinder. At least one shaping electrode which extends closer to the recording sheet than the bias electrode is selectively applied with a voltage of a polarity and magnitude to overcome the bias voltage and attract only the charged particles immediately adjacent to the shaping electrode to the recording sheet for printing.
Inventors
- 👤 Satoru Tomita
- 👤 Tamio Ohori
- 👤 Shuichi Karasawa
- 👤 Wasaburo Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:09
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/34; G03G15/344; G03G15/348
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
134 words
An electrostatic printing apparatus comprising in combination: a base electrode; means for applying a developing substance including charged particles onto the base electrode; means for positioning a recording sheet in contact with the base electrode; a printing head including at least one shaping electrode and at least one bias electrode disposed closely adjacent to the base electrode with the recording sheet disposed between the base electrode and the printing head; means for applying a first voltage between the base electrode and the bias electrode to urge the charged particles against the base electrode; and means for selectively applying a second voltage to the shaping electrode to overcome the first voltage and attract only those charged particles in an area of the base electrode adjacent to the shaping electrode to the recording sheet for printing.
Claim 2
Dependent Claim
134 words
An electrostatic printing apparatus comprising in combination: a base electrode; means for applying a developing substance including charged particles onto the base electrode; means for positioning a recording sheet in contact with the base electrode; a printing head including at least one shaping electrode and at least one bias electrode disposed closely adjacent to the base electrode with the recording sheet disposed between the base electrode and the printing head; means for applying a first voltage between the base electrode and the bias electrode to urge the charged particles against the base electrode; and means for selectively applying a second voltage to the shaping electrode to overcome the first voltage and attract only those charged particles in an area of the base electrode adjacent to the shaping electrode to the recording sheet for printing.
Claim 3
Dependent Claim
24 words
An apparatus as in claim 1, in which the shaping electrode is in the form of a rod oriented perpendicular to the base electrode.
Claim 4
Dependent Claim
24 words
An apparatus as in claim 2, in which the bias electrode is in the form of a cylinder coaxially disposed around the shaping electrode.
Claim 5
Dependent Claim
22 words
An apparatus as in claim 3, further comprising a pair of bias electrode plates disposed on opposite sides of the bias electrode.
Claim 6
Dependent Claim
20 words
An apparatus as in claim 4, further comprising an insulator disposed between the bias electrode and the bias electrode plates.
Claim 7
Dependent Claim
21 words
An apparatus as in claim 3, further comprising a cylindrical insulator coaxially disposed between the shaping electrode and the bias electrode.
Claim 8
Dependent Claim
47 words
An apparatus as in claim 2, in which the bias electrode is in the form of a block formed with a hole, the apparatus further comprising a cylindrical insulator disposed in the hole and being formed with a bore, the shaping electrode being disposed in the bore.
Claim 9
Dependent Claim
22 words
An apparatus as in claim 2, in which the bias electrode comprises two plates disposed on opposite sides of the shaping electrode.
Claim 10
Dependent Claim
19 words
An apparatus as in claim 1, further comprising an insulator disposed between the shaping electrode and the bias electrode.
Claim 11
Dependent Claim
19 words
An apparatus as in claim 1, in which the base electrode is in the form of a rotary cylinder.
Claim 12
Dependent Claim
21 words
An apparatus as in claim 1, in which the shaping electrode extends closer to the recording sheet than the bias electrode.
Claim 13
Dependent Claim
109 words
An apparatus as in claim 1 wherein said means for applying the first voltage between the base electrode and the bias electrode comprises applying the first voltage to cause the charged particles to be repelled against the base electrode and away from the recording sheet, and said means for selectively applying a second voltage to the shaping electrode comprises applying the second voltage of a polarity opposite to the polarity of the first voltage to overcome the first voltage and thereby attract charged particles substantially only in the area underlying the shaping electrode to the recording sheet for printing, whereby printing of high resolution and high contrast is effected.
Claim 14
Dependent Claim
28 words
An apparatus according to claim 1 wherein the application of said first and second voltages causes the creation of an electric field in the form of a funnel.
Claim 15
Dependent Claim
28 words
An apparatus according to claim 1 wherein the application of said first and second voltages causes the creation of an electric field in the form of a column.
References Cited (Backward Citations)
US2918580A
Cited
US3428025A
Cited
US3611419A
Cited
US3638610A
Cited
US3618118A
Cited
US3981268A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-02 | 1982-04-03 | 1982-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-02 | 1986-04-03 | 1986-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-02 | 1990-04-03 | 1990-10-03 | $7700.00 | Window Closed / Lapsed |