Method of operating an ink jet printhead within a predetermined temperature range
First Claim
Patent Images
1. A method of operating an ink jet printhead within a predetermined temperature range to print an image, said printhead comprising:
- an array of nozzles formed on a substrate, each nozzle including a nozzle opening, a displaceable thermal actuator for ejecting ink through said nozzle opening and an ink chamber;
an activation unit for each nozzle for controlling operation of said actuator;
at least one temperature sensor attached to said substrate for sensing the temperature of said substrate;
a temperature determination unit connected to said at least one temperature sensor; and
, an ink ejection drive unit coupled to said temperature determination unit and to said printhead;
said method including the steps of;
(a) sensing the temperature of said substrate with said at least one temperature sensor and said temperature determination unit;
(b) said ink ejection drive unit determining if said temperature is below a predetermined threshold;
(c) if said temperature is below said predetermined threshold, performing a preheating step of heating said actuators so that the printhead is heated to a temperature above said predetermined threshold;
(d) controlling said preheating step such that said thermal actuators are heated by pulses of energy that are insufficient to cause the ejection of ink from said printhead; and
, (e) utilizing said printhead to print said image once the temperature of said substrate reaches said predetermined threshold.
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Abstract
A method of operation of an inkjet printhead within a predetermined temperature range to print an image, wherein the printhead temperature is measured and if the temperature is below a predetermined threshold, the printhead is heated by pulses of energy to a desired temperature above the predetermined threshold temperature before printing. The actuators are displaceable thermal actuators and heating is controlled such that the pulses of energy are insufficient to cause ejection of fluid from the printhead.
9 Citations
15 Claims
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1. A method of operating an ink jet printhead within a predetermined temperature range to print an image, said printhead comprising:
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an array of nozzles formed on a substrate, each nozzle including a nozzle opening, a displaceable thermal actuator for ejecting ink through said nozzle opening and an ink chamber;
an activation unit for each nozzle for controlling operation of said actuator;
at least one temperature sensor attached to said substrate for sensing the temperature of said substrate;
a temperature determination unit connected to said at least one temperature sensor; and
,an ink ejection drive unit coupled to said temperature determination unit and to said printhead;
said method including the steps of;
(a) sensing the temperature of said substrate with said at least one temperature sensor and said temperature determination unit;
(b) said ink ejection drive unit determining if said temperature is below a predetermined threshold;
(c) if said temperature is below said predetermined threshold, performing a preheating step of heating said actuators so that the printhead is heated to a temperature above said predetermined threshold;
(d) controlling said preheating step such that said thermal actuators are heated by pulses of energy that are insufficient to cause the ejection of ink from said printhead; and
,(e) utilizing said printhead to print said image once the temperature of said substrate reaches said predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An ink jet printhead comprising:
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an array of nozzles formed on a substrate, each nozzle including a nozzle opening, a displaceable thermal actuator for ejecting ink through said nozzle opening and an ink chamber;
an activation unit for each nozzle for controlling operation of said actuator;
at least one temperature sensor attached to said substrate for sensing the temperature of said substrate;
a temperature determination unit connected to said at least one temperature sensor;
an ink ejection drive unit coupled to said temperature determination unit and to said printhead;
wherein, in use, said temperature determination unit utilizes an output from said at least one temperature sensor to sense a current temperature of said substrate before an ink ejection operation begins, and if said temperature is below a predetermined threshold, said ink ejection drive unit outputs a preheat activation signal to generate pulses of energy to heat each said thermal actuator to an extent sufficient to heat said substrate, while being insufficient for the ejection of ink from said array. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification