US 6,629,747 B1 · Method for determining ink drop velocity of carrier-mounted printhead

Abstract

A method for determining ink drop velocity of a printhead located at a gap above a print medium. A first ink mark is printed at a first printhead velocity. A second ink mark is printed at a different (in magnitude and/or direction) second printhead velocity. The ink for the second ink mark is ejected from the printhead at the same print ejection position used for the first ink mark plus a predetermined offset distance (if any). The distance between the ink marks is measured. The ink drop velocity is calculated using the measured distance, the predetermined offset distance, the first and second printhead velocities, and the predetermined gap. In another method, an ink mark is printed, a distance is measured between the ink mark and the ink-ejection position, and the ink drop velocity is calculated using the measured distance, the printhead velocity, and the gap.

Claims20

Dependent claims

A method for determining the ink drop velocity of a carrier-mounted printhead disposed at a predetermined gap above a print medium comprising the steps of:

a) printing a first ink mark on the print medium using the printhead with the printhead carrier moving along a scanning axis at a first printhead velocity, wherein the printhead begins ejecting ink corresponding to the first ink mark at an ink-ejection position along the scanning axis;
b) printing a second ink mark on the print medium using the printhead with the printhead carrier moving along the scanning axis at a second printhead velocity, having a second magnitude and a second direction along the scanning axis, which is different from the first printhead velocity, wherein the printhead begins ejecting ink corresponding to the second ink mark at the ink-ejection position plus a predetermined offset distance, and wherein the second ink mark is spaced apart from the first ink mark;
c) measuring the distance between the first and second ink marks;
and
d) calculating the ink drop velocity using the measured distance, the predetermined offset distance, the first and second printhead velocities, and the predetermined gap.

2 more elements

A method for determining the ink drop velocity of a carrier-mounted printhead disposed at a predetermined gap above a print medium comprising the steps of:

a) printing a first pattern of first ink marks on the print medium using the printhead with the printhead carrier moving along a scanning axis at a first printhead velocity, wherein the printhead begins ejecting ink corresponding to the first ink marks at equally-spaced-apart ink-ejection positions along the scanning axis;
b) printing a second pattern of second ink marks on the print medium using the printhead with the printhead carrier moving along the scanning axis at a second printhead velocity which is different from the first printhead velocity, wherein the printhead begins ejecting ink corresponding to the second ink marks at the ink-ejection positions plus a predetermined offset distance, and wherein the second ink marks are spaced apart from, and interleaved with, the first ink marks;
c) measuring the distance between adjacent and ink-ejection-position-corresponding first and second ink marks using an optical reflective sensor mounted on the printhead carrier;
and
d) calculating the ink drop velocity using the measured distance, the predetermined offset distance, the first and second printhead velocities, and the predetermined gap.

2 more elements

Dependencies are inferred from the claim text.

Method for determining ink drop velocity of carrier-mounted printhead

Life of this patent

Method for determining ink drop velocity of carrier-mounted printhead

Life of this patent

Abstract

Claims20