Inkjet Printing Apparatus with Ink Ejection Timing Correcting Function

Content Provider	The Lens
Abstract	An inkjet printing apparatus includes: a roller configured to rotate in synchronization with the print medium being conveyed; an encoder configured to output a pulse signal depending on a rotation angle of the roller; and a controller. The controller is configured to: perform an off-center information obtaining processing of driving the inkjet head to print a test pattern including dots arranged in a conveyance direction of the print medium and calculating an off-center information of the roller based on positions of the dots in the printed test pattern; and in the printing operation, correct the ejection timing of the ink by the inkjet head determined based on the pulse signal outputted from the encoder, based on the off-center information calculated in the off-center information obtaining processing.
Related Links	https://www.lens.org/lens/patent/010-208-934-774-997/frontpage
Language	English
Publisher Date	2019-10-03
Access Restriction	Open
Content Type	Text
Resource Type	Patent
Jurisdiction	United States of America
Date Applied	2019-03-19
Applicant	Riso Kagaku Corp
Application No.	201916357859
Claim	An inkjet printing apparatus comprising: an inkjet head configured to print an image on a print medium being conveyed by ejecting an ink to the print medium; a roller configured to rotate in synchronization with the print medium being conveyed; an encoder configured to output a pulse signal depending on a rotation angle of the roller; and a controller configured to control an ejection timing of the ink by the inkjet head in a printing operation, based on the pulse signal outputted from the encoder, wherein the controller is configured to perform an off-center information obtaining processing of driving the inkjet head to print a test pattern including dots arranged in a conveyance direction of the print medium and calculating an off-center information of the roller based on positions of the dots in the printed test pattern, and in the printing operation, correct the ejection timing of the ink by the inkjet head determined based on the pulse signal outputted from the encoder, based on the off-center information calculated in the off-center information obtaining processing. The inkjet printing apparatus according to claim 1 , further comprising a second roller separated from the roller and configured to rotate in synchronization with the print medium being conveyed, wherein the encoder is installed in the roller, the roller has an outer diameter different from an outer diameter of the second roller, and in the off-center information obtaining processing, the controller is configured to: generate an inter-dot distance data indicating a distance between adjacent ones of the dots in the conveyance direction in the printed test pattern; extract a rotation frequency component of the roller from the generated inter-dot distance data; and calculate the off-center information based on the extracted rotation frequency component. The inkjet printing apparatus according to claim 1 , comprising a plurality of the inkjet heads, wherein in the off-center information obtaining processing, the controller is configured to: drive at least two of the plurality of the inkjet heads to print the test patterns; and calculate the off-center information based on positional relationships of the dots between the test patterns printed respectively by the at least two of the plurality of the inkjet heads different from each other. The inkjet printing apparatus according to claim 3 , further comprising a second roller separated from the roller and configured to rotate in synchronization with the print medium being conveyed, wherein the encoder is installed in the roller, the roller has an outer diameter different from an outer diameter of the second roller, and in the off-center information obtaining processing, the controller is configured to: generate a positional relationship data indicating the positional relationships of the dots between the test patterns printed respectively by the at least two of the plurality of the inkjet heads different from each other; extract a rotation frequency component of the roller from the generated positional relationship data; and calculate the off-center information based on the extracted rotation frequency component.
CPC Classification	Typewriters;Selective Printing Mechanisms; I.E. Mechanisms Printing Otherwise Than From A Forme;Correction Of Typographical Errors
Extended Family	019-682-406-988-241 010-208-934-774-997 100-955-098-121-908 106-190-579-415-524 108-998-549-208-051
Patent ID	20190299604
Inventor/Author	Takemoto Kazuhiro
IPC	B41J2/045 B41J2/21
Status	Active
Owner	Riso Kagaku Corporation
Simple Family	019-682-406-988-241 010-208-934-774-997 100-955-098-121-908 106-190-579-415-524 108-998-549-208-051
CPC (with Group)	B41J11/008 B41J29/38 B41J2/04573 B41J2/04586 B41J2/2135 B41J2029/3935
Issuing Authority	United States Patent and Trademark Office (USPTO)
Kind	Patent Application Publication