US 12,011,923 B2
System and method for generating pre-fire pulses during a printing pause
Markus Keller, Schrobenhausen (DE); Martin Wilhelm, Maitenbeth (DE); Martin Stockmar, Poing (DE); Florian Hitzlsperger, Poing (DE); and Christoph Rummelsberger, Poing (DE)
Assigned to Canon Production Printing Hodling B.V., Venlo (NL)
Filed by Canon Production Printing Holding B.V., Venlo (NL)
Filed on Nov. 11, 2021, as Appl. No. 17/524,224.
Claims priority of application No. 102020129905.2 (DE), filed on Nov. 12, 2020.
Prior Publication US 2022/0143974 A1, May 12, 2022
Int. Cl. B41J 2/045 (2006.01)
CPC B41J 2/04573 (2013.01) [B41J 2/04581 (2013.01); B41J 2/04596 (2013.01); B41J 2/04598 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A controller for a print head of an inkjet printing device the print head including one or more nozzles configured to fire ink droplets onto a recording medium to print a print image, the controller comprising:
a memory that stores executable instructions;
a processor that is configured to execute the instructions to:
determine that the printing device is within a time-limited printing pause with a stationary recording medium;
generate, during the printing pause, a virtual timing signal independent of a movement of the recording medium; and
produce pre-ejection pulses of the one or more nozzles without ejection of ink during the printing pause, based on the virtual timing signal,
wherein the print head is installed immobile or fixed such that the print head is a stationary print head in the printing device and the printing device is configured for the recording medium to be directed past the stationary print head with a defined transport velocity;
the printing device comprises a sensor that is configured to generate a basic cycle signal based on the transport velocity of the recording medium, the sensor being formed as a rotary encoder comprising an encoder roller that is driven by the recording medium moving in the transport direction with said recording medium; and
during a printing operation of the printing device with a moving recording medium, the processor is further configured to execute the instructions to:
generate a line timing based on the basic cycle signal;
based on the line timing: produce ejection pulses of the one or more nozzles with ejection of ink to print a print image, and/or produce pre-ejection pulses of the one or more nozzles;
reduce the transport velocity of the recording medium, starting from an operating transport velocity in preparation for the printing pause; and
determine that the printing device is within a time-limited printing pause with a stationary recording medium in response to a detection that the transport velocity of the recording medium is less than or equal to a predefined velocity threshold, and/or in response to a detection that a printing pause mode has been activated by a user.