Control apparatus for an on-demand ink jet printing element
US4746937A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1986 |
| Grant date | May 24, 1988 |
| Priority date | — |
| Expiry date | May 23, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/0458
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
In an ink jet printing element in which the drop is expelled by generating a current pulse through the ink in the nozzle, in order to reduce the control voltage, a first pulse (Tr) for heating the ink is generated, followed by a vaporization pulse (Tv) with a delay such as to make the printing position independent of the direction of movement of the element with respect to the paper. The heating pulse (Tr) is generated by a circuit (31) controlled by a temperature sensor (34) so that the duration of the heating pulse has a negative temperature coefficient. The vaporization pulse (Tv) is generated by a circuit (32) manually controlled (potentiometer 39) to determine the pulse duration on the basis of the desired strength of the printing. The delay between the two pulses is controlled by a delay circuit (38), e.g. a monostable circuit. The two pulses are applied to a transformer (35) which generates the voltage between the electrodes. The two circuits (31, 32) may be constituted by one monostable circuit with separate RC networks sequentially enabled for determining the durations of the heating and vaporization pulses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.