Piezo bending transducer drop-on demand print head and method of actuating it

• US 6,460,979 B1
• Filed: 03/14/2000
• Issued: 10/08/2002
• Est. Priority Date: 03/15/1999
• Status: Expired due to Fees

• Current Assignee: Tally Computerdrucker GmbH
• Original Assignee: Tally Computerdrucker GmbH
• Inventors: Ederer, Ingo, Seitz, Hermann, Heinzl, Joachim
• Primary Examiner(s): NGUYEN, THINH H
• Application Number:
  US09/525,438
• Time in Patent Office: 938 Days
• Field of Search: 347/68, 347/70, 347/75, 347/57, 347/10
• US Class Current: 347/68
• CPC Class Codes: B41J 2/04525 reducing occurrence of cross talk
• CPC Class Codes: B41J 2/04581 controlling heads based on piezoelectric elements
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/14282 of cantilever type
• CPC Class Codes: B41J 2002/14354 Sensor in each pressure chamber

Abstract

Disclosed is a piezo bending transducer drop-on-demand print head and a method of actuating it. Each of the piezo bending transducers of a piezo bending transducer drop-on-demand print head is subjected to a sequence, corresponding to the desired print image, of triggering pulses each effecting a drop discharge movement and, assigned to each triggering pulse, each piezo bending transducer neighboring the piezo bending transducer triggered by the triggering pulse is subjected to a compensating pulse deflecting it. The piezo bending transducer drop-on-demand print head has a nozzle plate with nozzles arranged in series. Respectively assigned to each nozzle is a piezo bending transducer which can be subjected to a triggering pulse accompanied by a drop being discharged from the respective nozzle. There is a control device by which each of the piezo bending transducers can be subjected to triggering pulses and compensating pulses in accordance with the method of the invention.

Claims

1. A method of actuating a piezo bending transducer drop-on-demand print head, the print head having a nozzle plate with a plurality of nozzles arranged in series, wherein each of a series of piezo bending transducers is respectively assigned to each of said plurality of nozzles, comprising:

subjecting each of the piezo bending transducers to a sequence, corresponding to the desired print image, of triggering pulses each effecting a drop discharge movement; and

, assigned to each triggering pulse, each piezo bending transducer neighboring piezo bending transducer triggered by the triggering pulse being subjected to a compensating pulse deflecting it wherein the triggering pulse has an amplitude and each of the neighboring piezo bending transducers is subjected to a compensating pulse of a lower amplitude than said triggering pulse amplitude.

2. The method of claim 1 wherein the amplitude of the compensating pulse is lower than the amplitude of the triggering pulse by two thirds.

3. The method of claim 1 wherein the triggering pulse has a duration and each of the neighboring piezo bending transducers is subjected to a compensating pulse of a shorter duration than the duration of the triggering pulse.

4. The method of claim 1 wherein each of the neighboring piezo bending transducers is subjected to the compensating pulse with a time delay, preferably a delay of 80 microseconds, after the assigned triggering pulse.

5. The method of claim 1 wherein each of the neighboring piezo bending transducers is subjected to a compensating pulse by which the neighboring piezo bending transducer is initially deflected in an opposite direction from that of the triggered piezo bending transducer.

6. The method of claim 1 wherein there are neighboring two triggered piezo bending transducers, the piezo bending transducers neighboring the triggered piezo bending transducers are subjected to a compensating pulse of a larger amplitude than when said neighboring transducers are neighboring only one triggered piezo bending transducer.

7. The method of claim 6 wherein the piezo bending transducers are subjected to triggering pulses in a single group and the triggered piezo bending transducers are subjected to different triggering pulses, depending on whether both, one or none of the neighboring piezo bending transducers is/are likewise triggered.

8. The method of claim 7 wherein the piezo bending transducers are subjected to a triggering pulse of lower amplitude when one of the respectively neighboring piezo bending transducers is likewise triggered than if none of the respectively neighboring piezo bending transducers is likewise triggered, and are subjected to a triggering pulse of still lower amplitude if both the respectively neighboring piezo bending transducers are likewise triggered.

9. The method of claim 1 wherein the piezo bending transducers are subjected to triggering pulses in two groups at staggered time intervals, mutually neighboring piezo bending transducers respectively belonging to different groups.

10. The method of claim 1 wherein the neighboring piezo bending transducers are subjected to compensating pulses with a gradually falling edge.

11. The method of claim 1 further comprising a pre-operation trimming process.

12. The method of claim 11 wherein the trimming process comprises:

determining at least one of the amplitude, duration and/or time delay of compensating pulses or closing control pulses for each of the piezo bending transducers by varying the respectively applied compensating pulses or closing control pulses with respect to the respective amplitude, duration and/or time delay for intended setups of triggering pulses, measuring the drop discharge and crosstalk behavior in response to said variation; and

adjusting at least one of said amplitude, duration and/or time delay based on said measuring.

13. The method of claim 12 wherein only the duration and/or time delay of compensating pulses or closing control pulses are varied in the trimming process.

14. The method of claim 12 wherein the piezo bending transducer is used as a sensor in the trimming process, in that voltages which result from the triggering of a piezo bending transducer, the fluid movement brought about as a result and the deflecting of the neighboring piezo bending transducers cause to be induced in the latter are measured and evaluated for optimizing the drop discharge or crosstalk behavior.

15. The method of claim 12 wherein the piezo bending transducers neighboring the triggered piezo bending transducers being subjected during operation in progress to compensating pulses or closing control pulses for which the amplitude, duration and/or time delay are determined, in that voltages which result from the triggering of a piezo bending transducer, the fluid movement brought about as a result and the deflecting of the neighboring piezo bending transducers cause to be induced in the latter are measured and processed.

16. A method of actuating a piezo bending transducer drop-on-demand print head, the print head having a nozzle plate with a plurality of nozzles arranged in series, respectively assigned to which there is a piezo bending transducer of a series of piezo bending transducers wherein each of the piezo bending transducers is subjected to a sequence, corresponding to the desired print image, of triggering pulses each effecting a drop discharge movement and, assigned to each triggering pulse, each piezo bending transducer neighboring the piezo bending transducer triggered subjected to said pulse is subjected to a closing control pulse, by which the neighboring piezo bending transducer is deflected toward the nozzle assigned to it and is held there for a period wherein the triggering pulse has an amplitude and the neighboring piezo bending transducers are subjected to a closing control pulse of an amplitude which is no more than about one sixth of the amplitude of the triggering pulse.

17. A piezo bending transducer drop-on-demand print head, comprising:

a nozzle plate with a plurality of nozzles arranged in series;

a plurality of piezo bending transducers respectively assigned to each of said plurality of nozzles, wherein one or more of said transducers can be subjected to a triggering pulse accompanied by a drop being discharged from the respective nozzle pursuant to a sequence to form a desired print image;

a control device for subjecting each of the piezo bending transducers to a triggering pulse to effect a drop discharge movement and subjecting each piezo bending transducer neighboring each triggered piezo bending transducer to a compensating pulse;

said triggering pulse having an amplitude and said compensating pulse having an amplitude lower by two thirds.

18. The piezo bending transducer drop-on-demand print head of claim 17, which has at least three-pole piezo bending transducers, each with two active layers made of piezoceramic, and a control device, by which the triggering pulses are applied to one active layer and the closing control pulses are applied to the other active layer of the piezo bending transducer.

19. The piezo bending transducer drop-on-demand print head of claim 17 wherein the piezo bending transducers are piezo reed transducers and/or piezo bridge transducers.

20. A piezo bending transducer drop-on-demand print head, comprising

a nozzle plate with a plurality of nozzles arranged in series;

a plurality of piezo bending transducers wherein each of said plurality of said transducers is respectively assigned to each of said plurality of nozzles, said transducer being subjected to a triggering pulse accompanied by a drop being discharged from the respective nozzle, and a control device by which each of the plurality of piezo bending transducers is subjected to a triggering pulse having an amplitude and each transducer neighboring said triggered transducer is subjected to a closing control pulse having an amplitude, said control pulse amplitude being no more than one sixth of the triggering pulse amplitude.

21. The piezo bending transducer drop-on-demand print head of claim 20, which has at least three-pole piezo bending transducers, each with two active layers made of piezoceramic, and a control device, by which the triggering pulses are applied to one active layer and the closing control pulses are applied to the other active layer of the piezo bending transducer.

22. The piezo bending transducer drop-on-demand print head of claim 20 wherein the piezo bending transducers are piezo bridge transducers and/or piezo reed transducers.

23. A method of actuating a piezo bending transducer drop-on-demand print head, the print head having a nozzle plate with a plurality of nozzles arranged in series, wherein each of a series of piezo bending transducers is respectively assigned to each of said plurality of nozzles, comprising:

subjecting each of the piezo bending transducers to a sequence, corresponding to the desired print image, of triggering pulses each effecting a drop discharge movement; and

, assigned to each triggering pulse, each piezo bending transducer neighboring the piezo bending transducer triggered by the triggering pulse being subjected to a compensating pulse deflecting it wherein each of the neighboring piezo bending transducers is subjected to a compensating pulse by which the neighboring piezo bending transducer is initially deflected in an opposite direction from that of the triggered piezo bending transducer.

24. The method of claim 23 wherein the triggering pulse has an amplitude and each of the neighboring piezo bending transducers is subjected to a compensating pulse of a lower amplitude than said triggering pulse amplitude, preferably an amplitude lower by two thirds.

25. The method of claim 23 wherein the triggering pulse has a duration and each of the neighboring piezo bending transducers is subjected to a compensating pulse of a shorter duration than the duration of the triggering pulse.

26. The method of claim 23 wherein each of the neighboring piezo bending transducers is subjected to the compensating pulse with a time delay, preferably a delay of 80 microseconds, after the assigned triggering pulse.

27. The method of claim 23 wherein there are neighboring two triggered piezo bending transducers, the piezo bending transducers neighboring the triggered piezo bending transducers are subjected to a compensating pulse of a larger amplitude than when said neighboring transducers are neighboring only one triggered piezo bending transducer.

28. The method of claim 27 wherein the piezo bending transducers are subjected to triggering pulses in a single group and the triggered piezo bending transducers are subjected to different triggering pulses, depending on whether both, one or none of the neighboring piezo bending transducers is/are likewise triggered.

29. The method of claim 28 wherein the piezo bending transducers are subjected to a triggering pulse of lower amplitude when one of the respectively neighboring piezo bending transducers is likewise triggered than if none of the respectively neighboring piezo bending transducers is likewise triggered, and are subjected to a triggering pulse of still lower amplitude if both the respectively neighboring piezo bending transducers are likewise triggered.

30. The method of claim 25 wherein the piezo bending transducers are subjected to triggering pulses in two groups at staggered time intervals, mutually neighboring piezo bending transducers respectively belonging to different groups.

31. The method of claim 23 wherein the neighboring piezo bending transducers are subjected to compensating pulses with a gradually falling edge.

32. The method of claim 23 further comprising a pre-operation trimming process.

33. The method of claim 32 wherein the trimming process comprises:

determining at least one of the amplitude, duration and/or time delay of compensating pulses or closing control pulses for each of the piezo bending transducers by varying the respectively applied compensating pulses or closing control pulses with respect to the respective amplitude, duration and/or time delay for intended setups of triggering pulses, measuring the drop discharge and crosstalk behavior in response to said variation; and

adjusting at least one of said amplitude, duration and/or time delay based on said measuring.

34. The method of claim 33 wherein only the duration and/or time delay of compensating pulses or closing control pulses are varied in the trimming process.

35. The method of claim 33 wherein the piezo bending transducer is used as a sensor in the trimming process, in that voltages which result from the triggering of a piezo bending transducer, the fluid movement brought about as a result and the deflecting of the neighboring piezo bending transducers cause to be induced in the latter are measured and evaluated for optimizing the drop discharge or crosstalk behavior.

36. The method of claim 33 wherein the piezo bending transducers neighboring the triggered piezo bending transducers being subjected during operation in progress to compensating pulses or closing control pulses for which the amplitude, duration and/or time delay are determined, in that voltages which result from the triggering of a piezo bending transducer, the fluid movement brought about as a result and the deflecting of the neighboring piezo bending transducers cause to be induced in the latter are measured and processed.

37. A piezo bending transducer drop-on-demand print head, comprising:

a nozzle plate with a plurality of nozzles arranged in series;

a plurality of piezo bending transducer respectively assigned to each of said plurality of nozzles, wherein one or more of said transducers can be subjected to a triggering pulse accompanied by a drop being discharged from the respective nozzle pursuant to a sequence to form a desired print image;

a control device for subjecting each of the piezo bending transducers to a triggering pulse to effect a drop discharge movement and subjecting each piezo bending transducer neighboring each triggered piezo bending transducer to a compensating pulse wherein each of the neighboring piezo bending transducers is subjected to a compensating pulse by which the neighboring piezo bending transducer is initially deflected in an opposite direction from that of the triggered piezo bending transducer.

38. The piezo bending transducer drop-on-demand print head of claim 37, which has at least three-pole piezo bending transducers, each with two active layers made of piezoceramic, and a control device, by which the triggering pulses are applied to one active layer and the closing control pulses are applied to the other active layer of the piezo bending transducer.

39. The piezo bending transducer drop-on-demand print head of claim 37 wherein the piezo bending transducers are piezo reed transducers and/or piezo bridge transducers.

40. A piezo bending transducer drop-on-demand print head, comprising

a nozzle plate with a plurality of nozzles arranged in series;

a plurality of piezo bending transducers wherein each of said plurality of said transducers is respectively assigned to each of said plurality of nozzles, said transducer being subjected to a triggering pulse accompanied by a drop being discharged from the respective nozzle, and a control device by which each of the plurality of piezo bending transducers is subjected to a triggering pulse and each transducer neighboring said triggered transducer is subjected to a closing control pulse wherein the triggering pulse has an amplitude and the neighboring piezo bending transducers are subjected to a closing control pulse of an amplitude which is no more than about one sixth of the amplitude of the triggering pulse.

41. The piezo bending transducer drop-on-demand print head of claim 40, which has at least three-pole piezo bending transducers, each with two active layers made of piezoceramic, and a control device, by which the triggering pulses are applied to one active layer and the closing control pulses are applied to the other active layer of the piezo bending transducer.

42. The piezo bending transducer drop-on-demand print head of claim 40 wherein the piezo bending transducers being are piezo bridge transducers and/or piezo reed transducers.