Claims
- 1. A printerhead comprising:
- a common yoke;
- a plurality of pole pieces extending from said common yoke, said pole pieces being divided into a first group of pole pieces and a second group of pole pieces with the pole pieces in said first group alternating with the pole pieces of said second group;
- a permanent magnet coupled to said common yoke at a position opposite said pole pieces, said permanent magnet establishing a magnetic field in each of said pole pieces;
- a plurality of print hammers each having a first end rigidly coupled to said common yoke at a position adjacent said permanent magnet and a second end retractable against an end of a corresponding one of said pole pieces due to the magnetic field produced by said permanent magnet; and
- driving means, comprising a plurality of release coils which are provided only around pole pieces of said first group, for driving only the print hammers corresponding to said first group of pole pieces by at least substantially cancelling the magnetic field in the pole pieces of said first group to accomplish printing of said characters, wherein the magnetic field in each of the pole pieces of said second group is maintained substantially constant during printing of characters except for minor variations due to stray magnetic flux created when said release coils are driven.
- 2. A printer head comprising:
- a common yoke;
- a plurality of pole pieces extending from said common yoke parallel to one another;
- a permanent magnet coupled to said common yoke at a position opposite said pole pieces;
- a plurality of print hammer each having a first end rigidly coupled to said common yoke at a position adjacent said permanent magnet and a second end retractable against an end of a corresponding one of said pole pieces by a magnetic force produced by said permanent magnet; and
- driving means for driving only alternate ones of said print hammers by at least substantially cancelling the magnetic field in alternate ones of said pole pieces to accomplish printing of characters, said driving means comprising a plurality of release coils, all of said release coils being provided only around alternate ones of said pole pieces, there being no release coils around the other of said release coils.
- 3. The printer head of claim 2, further comprising a front yoke disposed parallel to said hammer elements between said hammer elements and a recording medium printed upon by said hammer elements.
- 4. The printer head of claim 3, wherein each of said print hammers comprise a leaf spring and a print pin, said print pin being disposed near said second end of said print hammer.
- 5. The printer head of claim 4 wherein said leaf spring is elastically deformable.
- 6. A printer of claim 2 further including print pins provided at said second ends of said print hammers only in positions in which the corresponding print hammer is driven.
- 7. The printer head of claim 6, further comprising a front yoke disposed parallel to said hammer elements between said hammer elements and a recording medium printed upon by said hammer elements.
Parent Case Info
This is a Continuation, of application Ser. No. 461,361, filed Jan. 23, 1983, now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
Parent |
461361 |
Jan 1983 |
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