Inkjet printer with dot alignment vision system
View Patent ↗Image processing of printed patterns of arrays of dots generated by an array of inkjet heads uses a vision system, including an HD color camera that can be a fixed focus or include autofocus and zoom capabilities. Pattern recognition techniques are used to analyze as many patterns as necessary to perform multiple alignment functions, such as dot size, shape, and integrity; unidirectional, bidirectional, and step alignments; physical position and straightness of jet packs; flatness of platen or media belt; mapping imperfections in rods and rails of guiding systems; and checking jet alignments from a reference jet to all other jet packs. From such image analysis, correction values are generated that are used to effect manual or automatic adjustment of the inkjet heads physical position, voltage, temperature, and firing pulse timing and/or duration; and to position the printed dots fired from the nozzles in the inkjet heads in the appropriate position.
1. An apparatus for aligning a printer having at least one inkjet head comprising:
said printer having said at least one inkjet head;
an enclosure that houses a vision system and pattern recognition module;
a shutter attached to said enclosure operable to protect said vision system;
wherein said enclosure is retrofitted to said printer and said vision system is retrofitted to or embedded in said printer for capturing printed information produced by said at least one inkjet head;
a processor communicably coupled to said vision system and to said printer,
said processor configured to cause said printer to print a pattern of an array of dots using said at least one inkjet head,
said processor configured to analyze said printed pattern information captured by said vision system with said pattern recognition module and to generate control signals for performing any of multiple alignment functions on said printer with said pattern recognition module,
said processor configured to automatically adjust said at least one inkjet head based at least in part on said control signals; and
wherein said shutter is operated when said vision system is not in use to protect said vision system.
2. The apparatus of claim 1 , said alignment functions comprising any of:
dot size, shape, and integrity;
unidirectional, bidirectional, and step alignments;
physical position and straightness of jet packs;
flatness of platen or media belt;
mapping imperfections in rods and rails of guiding systems;
checking jet alignments from a reference jet to all other jet packs; and
compensation for missing dots from disabled nozzles in one or more inkjet.
3. The apparatus of claim 1 , said control signals comprising:
correction values that are generated to effect manual or automatic adjustment of any of said inkjet heads' physical position, voltage, temperature, firing pulse timing and/or duration, and adjustments to the dot laydown pattern, and to accordingly position printed dots fired from said printer inkjet heads nozzles.