Printer

Patent metadata

Field	Value
Publication number	US-10933668-B2
Application number	US-201716309747-A
Country	US
Kind code	B2
Filing date	Jun 16, 2017
Priority date	Jun 17, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A printer comprising a printhead configured to selectively cause a mark to be created on a substrate. The printer comprises in a stepper motor having an output shaft coupled to the printhead, the stepper motor being arranged to vary the position of the printhead relative to a printing surface against which printing is carried out, and to control the pressure exerted by the printhead on the printing surface. The printer further comprises a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor. The printer further comprises a controller arranged to generate control signals for the stepper motor so as to cause a predetermined torque to be generated by the stepper motor; said control signals being at least partially based upon an output of said sensor.

First claim

The invention claimed is:

1. A printer comprising:
a printhead configured to selectively cause a mark to be created on a substrate and configured to rotate about a pivot that is configured to move along an axis;
a stepper motor comprising an output shaft coupled to a connection on the printhead, the stepper motor being arranged to vary a position of the printhead relative to a printing surface against which printing is carried out, and to control a pressure exerted by the printhead on the printing surface, by pivoting the printhead about the pivot, wherein the stepper motor pivots the printhead about the pivot by moving the connection along the axis relative to the pivot;
a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor; and
a controller arranged to generate control signals for the stepper motor so as to cause a predetermined torque to be generated by the stepper motor; said control signals being at least partially based upon an output of said sensor, wherein when the controller is moving the pivot along the axis the controller is also configured to monitor torque generated by the stepper motor and to control movement of the connection along the axis relative to the pivot to ensure the stepper motor maintains the predetermined torque.

2. A printer according to claim 1 , wherein:
said control signals for the stepper motor are arranged to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between the angular position of the output shaft of the stepper motor, and an orientation of the generated magnetic field; and
said generation of control signals is controlled so as to cause said field angle to have a predetermined value.

3. A printer according to claim 2 , wherein the predetermined value of the field angle is based upon a motor output characteristic.

4. A printer according to claim 3 , wherein the motor output characteristic comprises a maximum torque output.

5. A printer according to claim 2 , wherein the generated magnetic field has a predetermined angular orientation with respect to a housing of said stepper motor.

6. A printer according to claim 2 , wherein the control signals may be generated based upon the signal indicative of the angular position of the output shaft of the stepper motor so as to cause the field angle to have said predetermined value.

7. A printer according to claim 2 , wherein the control signals are generated so as to cause said magnetic field to have a predetermined magnitude.

8. A printer according to claim 1 , wherein the controller is arranged to control the stepper motor so as to cause a predetermined pressure to be exerted by the printhead on the printing surface.

9. A printer according to claim 1 , wherein the controller is arranged to control the stepper motor in first operating mode and a second operating mode, and wherein:
in the first operating mode, the controller is arranged to control the stepper motor so as to cause a predetermined pressure to be exerted by the printhead on the printing surface; and,
in the second operating mode, the controller is arranged to control the angular position of the output shaft of the stepper motor so as to control the position of the printhead relative to the printing surface.

10. A printer according to claim 9 , wherein in the second operating mode the printhead is spaced apart from the printing surface.

11. A printer according to claim 9 , wherein, in the first operating mode, the stepper motor is controlled based upon said output of said sensor.

12. A printer according to claim 9 wherein, in the first operating mode, the controller is arranged to generate control signals for the stepper motor so as to cause said predetermined torque to be generated by the stepper motor;
said control signals being at least partially based upon said output of said sensor.

13. A printer according to claim 9 , wherein said controller is configured to control the stepper motor in the second operating mode to cause the printhead to maintain a position in which it is spaced apart from the printing surface by a predetermined separation.

14. A printer according to claim 9 , wherein said controller is configured to control the stepper motor in the first operating mode to cause the printhead to move from a position in which it is spaced apart from the printing surface towards the printing surface.

15. A printer according to claim 1 , wherein generating the control signals for the stepper motor so as to cause the predetermined torque to be generated by the stepper motor comprises generating control signals for the stepper motor so as to cause a predetermined magnitude of current to flow in windings of the stepper motor.

16. A printer according to claim 1 , further comprising a printhead assembly, the printhead assembly comprising a first arm and a second arm, the first arm being coupled to the stepper motor via the connection, and the printhead being disposed on the second arm, wherein the stepper motor is arranged to cause movement of the first arm, thereby causing rotation of the second arm about the pivot, and causing the position of the printhead relative to the printing surface to vary.

17. A printer according to claim 9 , further comprising a printhead drive mechanism for transporting the pivot along a track extending generally parallel to the printing surface.

18. A printer according to claim 17 , wherein the controller is configured to control the stepper motor in the second operating mode to cause the printhead to maintain a position in which it is spaced apart from the printing surface by a predetermined separation during transport of the printhead along the track extending generally parallel to the printing surface.

19. A printer according to claim 17 , wherein the controller is configured to control the stepper motor in the first operating mode to cause said predetermined pressure to be exerted by the printhead on the printing surface during transport of the printhead along the track extending generally parallel to the printing surface.

20. A printer according to claim 17 , wherein the printhead drive mechanism comprises a printhead drive belt operably connected to the printhead and a second motor for controlling movement of the printhead drive belt; wherein the movement of the printhead drive belt causes the printhead to be transported along the track extending generally parallel to the printing surface.

Assignees

• Videojet Technologies Inc

Inventors

• Pfeffer Gary
• Buxton Keith

Classifications

• B41J2/325

  by selective transfer of ink from ink carrier, e.g. from ink ribbon or sheet · CPC title

• B41J25/312 Primary

  with print pressure adjustment mechanisms, e.g. pressure-on-the paper mechanisms · CPC title

• B41J2/17556

  Means for regulating the pressure in the cartridge · CPC title

• B41J25/316

  with tilting motion mechanisms relative to paper surface · CPC title

• B41J2/035

  by electric or magnetic field · CPC title