Thermal printer element tester
AssigneeRimage Corporation
InventorDavid J. Rother
Life of this patent
Estimating the term…
Abstract
A thermal transfer printer has been described that includes a print head integrity tester. The tester measures a resistance of each thermal element of the print head to determine if an element is defective. In one embodiment, the resistance is measured by monitoring a current through the element and comparing to a reference. The printer can also include a power strobe adjustment that automatically adjusts the power applied to the print head elements as the thermal elements age.
Claims19
A thermal transfer printer comprising:
- a thermal print head having a resistive heating element;
- and
- a test circuit coupled to selectively test the resistive heating element by comparing a current conducted through the resistive heating element with a reference.
A thermal transfer printer comprising:
- a receptacle to hold a print media;
- a thermal transfer print head positioned to print an image on the print media using a pigment source, the print head comprises a plurality of resistive thermal elements;
- a strobe circuit to apply power to the plurality of resistive thermal elements;
- a test circuit coupled to the print head to test a resistance of the plurality of resistive thermal elements.
A thermal transfer printer system comprising:
- a compact disc (CD) transporter having a robotic assembly to physically move CD's;
- and
- a thermal transfer printer comprising,
- a drawer to hold a target CD to be printed, wherein the robotic assembly loads and un-loads the CD in the drawer,
- a thermal transfer print head positioned to print an image on the CD using a pigment source, the print head comprises a plurality of resistive thermal elements,
- a strobe circuit to apply power to the plurality of resistive thermal elements,
- a test circuit coupled to the print head to test the plurality of resistive thermal elements, wherein the test circuit checks a resistance of each thermal element, and
- print head controller coupled to the strobe circuit and the test circuit, wherein the print head controller selectively couples the plurality of resistive thermal elements to the strobe circuit and monitors an output of the test circuit, the print head controller provides an indication when a defective resistive thermal element is detected.
A method of testing a thermal transfer printer comprising:
- initiating a test operation;
- measuring a resistive characteristic of a reference thermal element;
- establishing a threshold resistive characteristic;
- measuring a resistive characteristic of a non-reference thermal element;
- and
- comparing the resistive characteristics of then non-reference thermal element to the threshold resistive characteristic.
A method of testing a thermal transfer printer comprising:
- monitoring voltage drop across a test resistor coupled in series to an active reference thermal element;
- measuring a first time period required to develop a voltage drop across the test resistor that is equal to a reference voltage;
- establishing a threshold time period based on the measured first time period;
- substituting a test thermal element for the reference thermal element in series with the test resistor;
- measuring a second time period required to develop the voltage drop across the test resistor that is greater than the reference voltage;
- comparing the second time period to the threshold time period;
- and
- determining if the test thermal element is defective based upon the comparison.
A thermal transfer printer comprising:
- a drawer to hold a compact disc (CD);
- a thermal transfer print head positioned to print an image on the CD using a pigment source, the print head comprises a plurality of resistive thermal elements;
- a strobe circuit to apply power to the plurality of resistive thermal elements;
- a test circuit coupled to the print head to test a resistance of the plurality of resistive thermal elements.
Dependencies are inferred from the claim text.