Printer having variable hammer release drive
US4280404A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1979 |
| Grant date | Jul 28, 1981 |
| Priority date | — |
| Expiry date | Oct 3, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J9/52
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
In a dot matrix line printer in which selected ones of a plurality of hammers mounted on a reciprocating hammer bank are released in response to successive sets of serial data to print dots on a paper, the changing hammer release characteristics which are caused by different numbers of hammers being released with each new set of serial data are compensated for by an arrangement providing a varying hammer release signal in accordance with the number of hammers being released. The variable release signal is provided in the form of a variation in the time interval during which the drive amplifiers associated with hammer release coils are turned on, thereby effectively varying the length of a current pulse provided to each coil in direct proportion to the number of hammers to be released. A counter is preset, then counted down from the preset value in accordance with the number of hammers to be released as represented by a set of serial data being provided to a shift register. When the shift register is loaded, latches associated with the various stages of the shift register containing hammer release signals are set so as to turn on associated ones of the drive amplifiers. The counter …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.