Toner content monitoring system for use in a recording head for ink-jet printer

Patent 5905510 Issued on May 18, 1999. Estimated Expiration Date:

September 20, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3494328

3682132

3727065

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Inventors

Assignee

NEC Corporation

Application

No. 718245 filed on 09/20/1996

US Classes:

347/7, Fluid content (e.g., moisture or solvent content, ink refilling, liquid level)399/64Optical detector

Examiners

Primary: Burr, Edgar S.
Assistant: Colilla, Daniel J.

Attorney, Agent or Firm

Sughrue, Mion, Zinn, Macpeak & Seas, PLLC

Foreign Patent References

0571784 EP. 12/13/1993
0597628 EP. 05/13/1994
0661162 EP. 07/13/1995
55-84674 JP 06/13/1980
62-156963 JP 07/13/1987
A 8-90825 JP. 04/13/1996
A 9-1824 JP. 07/13/1997

International Class

B41J 2/1/95

Foreign Application Priority Data

1995-09-21 JP

Abstract

A system for monitoring the toner content in ink. The system comprising a light source and a photo-detector disposed in a ink chamber wall, a controller and a display unit. A content-monitoring voltage V1 and an operation-checking voltage V2 are determined from experiments in advance. V1 and V2 are such light source voltages when a predetermined current Ith is obtained from the photo-detector for the minimum and maximum allowable toner contents, respectively. In usual operation in user site, operation of the system is checked with the light source voltage set for V2 in response to a power-on or a reset. Then, a monitoring of the toner content is started with the light source voltage set for V1. In a toner content monitoring, the sensor current is checked to see if it is equal to or larger than Ith.