The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 2002
Filed:
Feb. 04, 2000
Toshiyuki Asaka, Tokyo, JP;
Hideaki Ishimizu, Tokyo, JP;
Shigeru Tsunoda, Tokyo, JP;
Toshiro Suemune, Tokyo, JP;
Oki Data Corporation, Tokyo, JP;
Abstract
An apparatus for driving a printhead has a timer, a power supply, and a controller. The power supply applies a drive voltage to the printhead to eject ink drops from the printhead. The timer counts an elapsed time during which the printhead does not eject ink drops. The controller performs an ejection test where the drive voltage drives the printhead a plurality of times to eject a plurality of ink drops. The controller drives the power supply to increase the drive voltage in accordance with a length of the elapsed time. The ejection test is performed at a predetermined length of the elapsed time, the drive voltage and the predetermined length of the elapsed time are selected in accordance with a decrease in an ejection speed of the ink drops. The controller controls the drive voltage such that the surface of meniscus of ink in the orifice is subjected to fine vibration before the ink drop is ejected. The surface of the meniscus is subjected to fine vibration prior to either a printing operation or an ejection test. When the ejection test is performed, the controller determines the drive voltage by adding a first correction voltage to a drive voltage required for a printing operation. When the surface of meniscus is subjected to fine vibration, the controller determines the drive voltage by adding a second correction voltage to the drive voltage.