An ink jet printing apparatus is provided which can suppress defective ejection of ink from the nozzles. An element array with a plurality of print elements arranged therein is divided into a plurality of groups of print elements. For each of the plurality of groups, the apparatus determines whether any area undergoes a failure to perform a normal printing operation. If the apparatus determines, for any of the plurality of groups, that any area is likely to undergo the failure, when the print medium is printed based on the print data corresponding to the area, control is performed in such a manner that a first amount of energy supplied to drive one print element is greater than a second amount of energy supplied to drive one print element immediately before the print medium is printed based on the print data corresponding to the area.

An inkjet printing system includes a drop ejector array module having a temperature sensor and a logic circuit for sequentially selecting one or more drop ejectors in the array. The system also includes an image data source for providing an image data signal, a memory for storing a temperature correction factor, and a memory for storing at least one drop ejector correction factor. The system includes a fire pulse generator configured to receive signals corresponding to the temperature sensor, the temperature correction factor and the at least one drop ejector correction factor and to output a fire pulse waveform. Also included is a heating pulse generator configured to receive signals corresponding to the temperature sensor and the temperature correction factor and to output a heating pulse waveform. A waveform selector is provided for selecting either a fire pulse waveform or a heating pulse waveform based on the image data signal.

According to an example, in a method for enhancing temperature distribution uniformity across a printer die, in which the printer die includes a plurality of drop generators arranged in a plurality of columns, a warming map that identifies the drop generators of the plurality of drop generators that are to be supplied with warming pulses to enhance temperature distribution uniformity across the printer die may be accessed. The warming map may identify a non-uniform distribution of the drop generators across a column of the plurality of columns. In addition, the warming map may be implemented to supply the drop generators identified in the warming map as the drop generators that are to receive the warming pulses.

Disclosed is a liquid discharge method of discharging liquid with a liquid discharge head having a heating surface that contacts and heats the liquid and a discharge port that faces the heating surface and discharges the liquid. The method includes heating the liquid through the heating surface to generate a bubble such that the bubble communicates with an atmosphere, thereby discharging the liquid. The liquid that is being discharged from the discharge port includes a trailing portion. The trailing portion moves toward the heating surface in response to a reduction in volume of the bubble and contacts the heating surface. The method further includes heating the trailing portion through the heating surface while the trailing portion is in contact with the heating surface, thereby generating a bubble.

A printing apparatus comprises: a plurality of printing elements; driving circuits that have at least one source follower transistor and correspond to each of the plurality of printing elements; and a control unit configured to, in a case where a number of printing elements driven simultaneously does not exceed a predetermined number, perform a first control for driving the at least one source follower transistor by a fixed pulse width irrespective of the number of printing elements driven simultaneously, and, in a case where the number of printing elements driven simultaneously exceed the predetermined number, perform a second control for changing a pulse width to drive the at least one source follower transistor based on the number of printing elements driven simultaneously.

According to an example, in a method for enhancing temperature distribution uniformity across a printer die, in which the printer die includes a plurality of drop generators arranged in a plurality of columns, a warming map that identifies the drop generators of the plurality of drop generators that are to be supplied with warming pulses to enhance temperature distribution uniformity across the printer die may be accessed. The warming map may identify a non-uniform distribution of the drop generators across a column of the plurality of columns. In addition, the warming map may be implemented to supply the drop generators identified in the warming map as the drop generators that are to receive the warming pulses.

In an a method to stabilize the ink meniscus at a nozzle opening of a nozzle of a print head including the nozzle and one or more adjacent nozzles to the nozzle, the nozzle can be induced to generate a signal pulse at an activation time. The signal pulse can be a pre-fire pulse (e.g. a negative pressure reduction pulse), where, for example, no ink is ejected. The inducement to generate the pulse can depend on the number of adjacent nozzles that eject ink at the activation time. The negative pressure in the nozzle can then be reduced, and nozzle failures due to air suction may be avoided.

A driving pulse to be applied is changed when an overlapped level of invert timing of driving pulse is large.

A liquid ejection method includes ejecting liquid from an ejection opening, using a liquid ejection head including a heating surface configured to heat the liquid and the ejection opening corresponding to the heating surface, by heating the liquid with the heating surface to produce a bubble communicating with air through the ejection opening such that at least a part of the heating surface is exposed to the air through the ejection opening, wherein the liquid is heated with the heating surface for 0.5 microseconds or shorter to produce a bubble communicating with the air through the ejection opening such that at least a part of the heating surface is exposed to the air through the ejection opening, in order to eject the liquid from the ejection opening.

An inkjet printing system includes at least one drop ejector array module having an array of drop ejectors disposed on a substrate. A primary temperature sensor is located near a first set of drop ejectors. At least one secondary temperature sensor is located near a second set of drop ejectors. Temperature comparison circuitry on the substrate is configured to compare signals from the primary temperature sensor and the at least one secondary temperature sensor. Pulse modification circuitry on the substrate is electrically connected to the temperature comparison circuitry and is configured to modify an input pulse waveform. The inkjet printing system also includes a controller that is electrically connected to the primary temperature sensor via a temperature output pad and to the pulse modification circuitry via a pulse waveform input pad.