Printhead and method for controlling print quality using printhead temperature

• US 7,611,220 B2
• Filed: 05/02/2007
• Issued: 11/03/2009
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Do; An H
• Application Number:
  US11/743,659
• Publication Number:
  US 20070222807A1
• Time in Patent Office: 916 Days
• Field of Search: 347/17, 347/19
• US Class Current: 347/17
• CPC Class Codes: B41J 2/04505 aiming at correcting alignment
• CPC Class Codes: B41J 2/04516 preventing formation of satellite drops
• CPC Class Codes: B41J 2/04518 reducing costs
• CPC Class Codes: B41J 2/0452 reducing demand in current or voltage
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04553 detecting ambient temperature
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/04565 detecting heater resistance
• CPC Class Codes: B41J 2/0457 Power supply level being detected or varied
• CPC Class Codes: B41J 2/04571 detecting viscosity
• CPC Class Codes: B41J 2/04585 controlling heads based on thermal bent actuators
• CPC Class Codes: B41J 2/04588 using a specific waveform
• CPC Class Codes: B41J 2/0459 Height of the driving signal being adjusted
• CPC Class Codes: B41J 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2/04593 Dot-size modulation by changing the size of the drop
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/04598 Pre-pulse
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/155 : for line printing
• CPC Class Codes: B41J 2/1623 : bonding and adhesion
• CPC Class Codes: B41J 2/1628 : dry etching
• CPC Class Codes: B41J 2/1629 : wet etching
• CPC Class Codes: B41J 2/1631 : photolithography
• CPC Class Codes: B41J 2/1632 : machining
• CPC Class Codes: B41J 2/1635 : dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1639 : sacrificial molding
• CPC Class Codes: B41J 2/1642 : thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1646 : thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 : Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2002/14491 : Electrical connection
• CPC Class Codes: B41J 25/005 : for serial printing movements superimposed to character- or line-spacing movements
• CPC Class Codes: G06K 15/102 : using ink jet print heads
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

A printhead and method of operation for controlling the print quality using temperature. A sensor senses the printhead temperature before printing begins. The controller compares it to a threshold temperature that represents desired ink drop characteristics. If the printhead temperature is below the threshold, it initiates heating elements and adjusts the heating elements until the threshold temperature has been reached.

Claims

1. A method of printing ink drops with a printhead over a print area, the method comprising the steps of:

receiving a temperature of the printhead before printing begins;

receiving resistivity feedback from the printhead, said resistivity feedback comprising information regarding a resistivity of individual heating elements in the printhead;

comparing the temperature with a predefined threshold temperature;

initiating heating elements if the temperature is below the threshold temperature;

turning off the heating elements when the threshold temperature of the printhead has been reached to produce desired characteristics in the ink drops; and

,

pulsing the heating elements with electrical energy to impart sufficient kinetic energy to ink in the printhead to eject the ink drops with desired characteristics, wherein the temperature of the printhead and the resistivity feedback are together used to determine an amount and timing of electrical energy pulsed to each heating element.

2. A method according to claim 1 wherein predefining the threshold temperature for the ink drops uses ink property data stored in a memory associated with the ink being supplied to the printhead.

3. A method according to claim 2 wherein the data is stored in the form of a look up table.

4. A method according to claim 1 wherein the threshold temperature relates to a predetermined size of the ink drops.

5. A method according to claim 4 wherein the predetermined size of the ink drops is less than 2 pico liters.

6. A method according to claim 4 wherein the predetermined size of the ink drops is between 1 pico liter and 0.7 pico liters.

7. A method according to claim 1 wherein the threshold temperature relates to a predetermined ejection velocity of the ink drops.

8. A method according to claim 7 wherein the predetermined ejection velocity is between 2 meters/sec and 4 meters/sec.

9. A method according to claim 1 wherein the heating elements take less than 50 milliseconds to heat the printhead to the threshold temperature.

10. A method according to claim 9 wherein the threshold temperature is about 30 degrees C. above ambient temperature.