Back to results
US 4,901,088 AGranted
Method and apparatus for high resolution ink jet printing
OwnerCarl H. Hertz, Bo A. Samuelssoninventors
Life of this patent
Estimating the term…
Abstract
A coincidence-preventing circuit prevents the graininess of image which results form coincidental arrival of a clock pulse and a load pulse at a circuit, such as a down counter, the output from which controls the timing and density of the image produced on a recording medium by an ink jet.
Claims8
An ink jet printing method wherein a record is produced by applying varying amounts of ink on a plurality of pixel locations of a record medium, said method comprising the steps:
- (a) generating an ink jet directed towards said record medium, said ink jet breaking up into a series of drops with a predetermined drop formation rate,
- (b) applying an electric charge of predetermined magnitude to selected drops,
- (c) deflecting each charged drop as a function of its charge to determine whether the drop travels along a recording path to reach said recording medium or is intercepted,
- (d) producing relative transverse movement between said drop path and said recording medium,
- (e) generating a first signal indicative of the drop formation rate,
- (f) generating a second signal from said relative movement, the second signal being indicative that pixel position on the record medium is aligned with said drop path,
- (g) deriving a density value for the aligned pixel position in response to said second signal,
- (h) generating a print pulse signal of predetermined length between leading and trailing edges in response to said derived density value and said first signal, said density value controlling the length and said first signal controlling the time of occurrence of the leading edge of said print pulse signal,
- (i) controlling said charging step (b) by means of said print pulse signal, the improvement consisting in
- (j) combining said first and second signals to establish a non-coincidental time relationship between the time at which said density value deriving step (g) occurs and the time when the leading edge of the print pulse occurs.
7 more elements
An ink jet printing apparatus wherein a record is produced by applying various amounts of ink on a plurality of pixel locations of a record medium, said apparatus comprising:
- (a) means (10) for generating an ink jet (16) directed towards said record medium (20), said ink jet breaking up into a series of drops (18) with a predetermined drop formation rate,
- (b) means (24, 53) for selectively charging said drops (18),
- (c) means (28) for applying a deflecting force to each charged drop as a function of its charge to determine whether the drop travels along a recording path to said record medium (20) or is intercepted by intercepting means (26),
- (d) means (21) for producing relative movement between said path and said record medium (20),
- (e) means (34) for generating a first signal indicative of said drop formation rate,
- (f) means (40) for generating a second signal depending on said relative movement, the second signal being indicative that a pixel position on said record medium is aligned with said path of said drops which reach said record medium,
- (g) means (36) for deriving a density value for the aligned pixel in response to said second signal,
- (h) means (44) for generating a print pulse signal having a predetermined length between leading and trailing edges in response to said derived density value and said first signal, said density value controlling the length and said first signal controlling the time of occurrence of the leading edge of said print pulse signal, the improvement consisting in
- (i) means (54) for combining said first and second signals to establish a non-coincidental time relationship between the time at which said density value is derived and the time at which the leading edge of said print pulse signal occurs.
6 more elements
Dependencies are inferred from the claim text.