×

Recognition of ink expiry in an ink jet printing head

  • US 5,414,452 A
  • Filed: 05/27/1993
  • Issued: 05/09/1995
  • Est. Priority Date: 06/08/1992
  • Status: Expired due to Term
First Claim
Patent Images

1. A method for recognition of expiry of ink in a reservoir (16) of an ink jet printing head in which drops of ink are expelled from a nozzle in response to electrical pulses, comprising the steps of:

  • counting a number of drops progressively expelled in response to the pulses;

    adding to said number a second number of drops (m) equivalent to ink evaporated from the reservoir to obtain a total number of drops; and

    generating an ink expiry signal when the total number of drops is equal to or exceeds a known volume of ink in said reservoir, expressed as a number of equivalent drops (N).

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×