US 5,495,270 A · Method and apparatus for producing dot size modulated ink jet printing

Abstract

An ink jet (10) apparatus and method provides high-resolution gray scale printing by providing multiple PZT drive waveforms (100, 110, 120), each having a spectral energy distribution that excites a different modal resonance of ink in an ink jet print head orifice (14). By selecting the particular drive waveform that concentrates spectral energy at frequencies associated with a desired oscillation mode and that suppresses energy at the other oscillation modes, an ink drop (170, 180, 190) is ejected that has a diameter proportional to a center excursion size of the selected meniscus surface oscillation mode. The center excursion size of high order oscillation modes is substantially smaller than the orifice diameter, thereby causing ejection of ink drops smaller than the orifice diameter. Conventional orifice manufacturing techniques may be used because a specific orifice diameter is not required. Jetting reliability and contaminant susceptibility are, thereby, improved by eliminating the need for an unconventionally small orifice. Changing a selected PZT drive waveform amplitude changes drop ejection velocity without changing drop volume. This invention, therefore, provides for selection of ejected ink drop volumes having substantially the same ejection velocity over a wide range of ejection repetition rates.

Claims35

Dependent claims

Apparatus for ejecting a fluid from an orifice having an orifice diameter, comprising:

a pressure chamber coupled to the orifice, the fluid forming a meniscus in the orifice;
and
a transducer driver generating a first energy input that actuates a transducer to excite in the meniscus a first center excursion size in response to the first energy input, the first energy input having a spectral energy distribution that excites the meniscus to eject a first drop of the fluid from the orifice, the first drop having a first drop diameter that is less than the orifice diameter and a first drop ejection velocity, and after the first drop of the fluid is ejected, the transducer driver generates a second energy input that actuates the transducer to excite in the meniscus a second center excursion size in response to the second energy input, the second energy input having a spectral energy distribution that excites the meniscus to eject a second drop of the fluid from the orifice, the second drop having a second drop diameter different than the first drop diameter and a second drop ejection velocity that is substantially equal to the first drop ejection velocity.

Dependencies are inferred from the claim text.

Method and apparatus for producing dot size modulated ink jet printing

Life of this patent

Method and apparatus for producing dot size modulated ink jet printing

Life of this patent

Abstract

Claims35