Abstract: A method of ink jet printing using an ink jet imaging device including a plurality of nozzles arranged for expelling droplets of an ink by actuation of an ink channel includes the steps of: a) providing a bit map of a spit pattern comprising an arrangement of refresh dots to be printed by each of the plurality of nozzles; and d) printing the bitmap of the spit pattern. The spit pattern includes a plurality of clusters of refresh dots, each cluster including at least two sequential refresh dots expelled from a single nozzle. A spit pattern for use in such a method is disclosed.

Abstract: A method of ink jet printing wherein liquid ink is supplied to a plurality of nozzles via a common ink supply passage, and actuators associated with the nozzles are controlled to cause ink droplets to be expelled from the nozzles in accordance with image information to be printed, characterized by the steps of detecting a situation where a number of the nozzles which are connected to the common ink supply passage and are presently active but stop printing within a given time interval is larger than a given maximum number; if that situation is detected, activating at least one actuator associated with one of the nozzles that stop printing with sub-threshold agitation pulses which cause an agitation of a meniscus in the nozzle without a droplet being expelled.

Abstract: A method of ink jet printing, wherein liquid ink is supplied to a plurality of nozzles via a common ink supply passage, and actuators associated with the nozzles are controlled to cause ink droplets to be expelled from the nozzles in accordance with image information to be printed, characterized by the steps of: detecting a situation where a number of the nozzles which are connected to the common ink supply passage and are presently active but stop printing within a given time interval is larger than a given maximum number; if that situation is detected, activating at least one actuator associated with one of the nozzles that stop printing with sub-threshold agitation pulses which cause an agitation of a meniscus in the nozzle without a droplet being expelled.

Abstract: In a method for operating an inkjet print head for generating a droplet of a liquid, the inkjet print head comprises a number of ejection units, each ejection unit comprising a piezo-electric actuator having a signal electrode, a common electrode and a piezo-electric layer interposed between the signal electrode and the common electrode. The method comprises providing a non-jetting pulse signal on a common electrode, wherein the non-jetting pulse signal is adapted to generate a pressure wave in the liquid in the corresponding ejection unit without expelling a droplet of the liquid. The method further comprises providing a jetting pulse signal on a signal electrode, wherein the jetting pulse signal is adapted to generate a pressure wave in the liquid in the corresponding ejection unit such that a droplet of the liquid is expelled. Further, an inkjet print head assembly comprising an inkjet print head and a control circuitry is provided.

Abstract: A printing system for printing a fluid includes a print head for ejecting droplets of the fluid; a first fluid storing section for storing a first amount of the fluid; a second fluid storing section for storing a second amount of the fluid, the second fluid storing section being in fluid communication to the pressure chamber in a power down situation; and a pre-tension device configured for arranging the second amount of the fluid in a pre-tension state in the second fluid storing section, thereby providing a positive fluid pressure on the nozzle in a power down situation, which positive fluid pressure is selected such that a third amount of fluid passes through the nozzle in response to said positive fluid pressure and forms a film on the nozzle plate. The printing system according to the invention supports the recovery of the print head after a power down situation.

Abstract: A printing system for printing a fluid includes a print head for ejecting droplets of the fluid; a first fluid storing section for storing a first amount of the fluid; a second fluid storing section for storing a second amount of the fluid, the second fluid storing section being in fluid communication to the pressure chamber in a power down situation; and a pre-tension device configured for arranging the second amount of the fluid in a pre-tension state in the second fluid storing section, thereby providing a positive fluid pressure on the nozzle in a power down situation, which positive fluid pressure is selected such that a third amount of fluid passes through the nozzle in response to said positive fluid pressure and forms a film on the nozzle plate. The printing system according to the invention supports the recovery of the print head after a power down situation.