US4339702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stepping motor drive apparatus
Assignee: Ricoh Co Ltd
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Filing: 1980-09-08
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Granted: 1982-07-13
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Expires: 2000-09-08
Abstract
Abstract A stepping motor (31) drives a load (33) such as an ink ribbon in a printer which exerts reverse torque on the motor shaft (32) thus displacing the shaft (32) slightly in the reverse direction when a low hold current is applied to a motor phase. Prior to switching the motor (31) to a next phase for rotation, a high drive current is applied to the present phase. After a certain length of time which is sufficient for the shaft (32) to be moved to the correct present position, the phases are sequentially switched while the high drive current is applied for rotating the shaft (32) and load to a new position.
Inventors
- 👤 Shigeyuki Araki
- 👤 Hideyasu Yamanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:55
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/04; H02P8/08; H02P8/24
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
91 words
A motor drive apparatus comprising a multi phase motor having a shaft and drive means for sequentially energizing the motor phases with a high drive current for rotating the shaft and for energizing a present motor phase with a low hold current for holding the shaft in a respective present position, characterized in that, prior to energizing a next motor phase for rotating the shaft away from the present position, the drive means is constructed to energize the present phase with the high drive current for a predetermined length of time.
Claim 2
Dependent Claim
91 words
A motor drive apparatus comprising a multi phase motor having a shaft and drive means for sequentially energizing the motor phases with a high drive current for rotating the shaft and for energizing a present motor phase with a low hold current for holding the shaft in a respective present position, characterized in that, prior to energizing a next motor phase for rotating the shaft away from the present position, the drive means is constructed to energize the present phase with the high drive current for a predetermined length of time.
Claim 3
Dependent Claim
24 words
An apparatus as in claim 1, further comprising a load which is driven by the shaft and exerts a reverse torque on the shaft.
References Cited (Backward Citations)
US3893012A
Cited
US4262240A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-12 | 1986-01-11 | 1986-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-12 | 1990-01-11 | 1990-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-12 | 1994-01-11 | 1994-07-13 | $7700.00 | Window Closed / Lapsed |