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EP0147575A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Drop-on-demand ink jet printers

Assignee: JP Morgan Delaware
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Filing: 1984-11-06
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Granted: —
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Expires: 2004-11-06
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Abstract

Abstract An ink jet drop-on-demand printing system comprising an ink jet print head (10) having an ink cavity (23) supplied with a suitable ink. An electromechanical transducer (16) is mounted in mechanical communication with the ink cavity, and a control means (14) is provided to selectively actuate the transducer to produce an ink drop of a selected size. To produce ink drops of a selected size a source of electrical signals comprised in the control means produces electrical drive signals (60a to 60n) each separated by a fixed time delay (τ) which is short with respect to the drop-on-demand drop production rate (T). Each electrical drive signal (60a to 60n) is capable of ejecting a predetermined volume of ink and all ejected the volumes of ink merge to form a single drop prior to the time the ink drops reach the print medium for printing. By selecting groups (e.g. 60a to 60d, or 60a to 60f) from the signals (60a to 60n) the size of the merged drop can be selected.

Inventors

  • 👤 Francis Chee-Shuen Lee
  • 👤 Ross Neal Mills
  • 👤 Robert Nolan Payne
  • 👤 Frank Eberhard Talke

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 17:49
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; B41J2/2121; B41J2/2128; B41J2202/00; B41J2202/01; B41J2202/06

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 204 words
A drop-on-demand ink jet printing system comprising an ink jet head having (10) an ink cavity (22), an orifice (20) communicating with said ink cavity and an electromechanical transducer (16) mounted in mechanical communication with said ink cavity, a source (14) of electrical drive signals repeatable at a predetermined drop-on-demand drop production rate, and means to selectively actuate said electromechanical transducer in response to said electrical drive signals to force a single drop of ink from said orifice; said system being characterised by further comprising; means (52) for selectively producing at least one additional electrical drive signal each with a fixed time delay with respect to the immediately preceding electrical drive signal, said fixed time delay being short with respect tc said drop-on-demand drop production rate; and means (36, 56, 58) to actuate said electromechanical transducer with each of or only selected ones of said additional electrical drive signals to produce a quantity of ink having a predetermined volume from said orifice, said quantities of ink merging into said preceding single drop of ink prior to the time the drop reaches the print medium for printing whereby each ink drop can be produced having a selected one of a plurality of possible drop sizes.
Claim 2
Dependent Claim 204 words
A drop-on-demand ink jet printing system comprising an ink jet head having (10) an ink cavity (22), an orifice (20) communicating with said ink cavity and an electromechanical transducer (16) mounted in mechanical communication with said ink cavity, a source (14) of electrical drive signals repeatable at a predetermined drop-on-demand drop production rate, and means to selectively actuate said electromechanical transducer in response to said electrical drive signals to force a single drop of ink from said orifice; said system being characterised by further comprising; means (52) for selectively producing at least one additional electrical drive signal each with a fixed time delay with respect to the immediately preceding electrical drive signal, said fixed time delay being short with respect tc said drop-on-demand drop production rate; and means (36, 56, 58) to actuate said electromechanical transducer with each of or only selected ones of said additional electrical drive signals to produce a quantity of ink having a predetermined volume from said orifice, said quantities of ink merging into said preceding single drop of ink prior to the time the drop reaches the print medium for printing whereby each ink drop can be produced having a selected one of a plurality of possible drop sizes.
Claim 3
Dependent Claim 43 words
A drop-on-demand ink jet printing system as claimed in claim 1 in which said additional electrical drive signals have a pulse width of L/a where L is the length of said ink cavity and a is the velocity of sound in said ink.
Claim 4
Dependent Claim 45 words
A drop-on-demand ink jet printing system as claimed in claim 1, 2 or 3 in which said fixed time delay is about 1.5 to 2 L/a where L is the length of said ink cavity and a is the velocity of sound in said ink.
Claim 5
Dependent Claim 42 words
A drop-on-demand ink jet printing system as claimed in claim 1, 2 or 3 in which all of said quantities of ink having a predetermined volume merge into a single drop prior to break-off of the ink drop of the selected size.
Claim 6
Dependent Claim 34 words
A drop-on-demand ink jet printing system as claimed in claim 1, 2, 3 or 4 in which the size of said orifice is within the range of from about 30 to about 50 micro-meters.

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