A printing apparatus includes a printhead having a nozzle to eject liquid and an actuator associated with the nozzle. A controller is provided to activate a recovery sequence including heating the printhead without firing drops in a first phase, activating the actuator to fire 1000 drops or more from the nozzle in a second phase after the first phase, and heating the printhead and applying pressure to expel liquid from the nozzle in a third phase after the second phase

A method is provided for determining, in a liquid ejection apparatus, a state of a liquid ejection from an ejection port. The liquid ejection apparatus includes the ejection port configured to eject a liquid, a substrate comprising an electrothermal conversion element configured to generate heat for ejecting the liquid from the ejection port, and a temperature detection unit configured to detect temperature information on the substrate. The method includes performing a first comparison process to compare the temperature information on the substrate detected at a first timing by the temperature detection unit with a first threshold value, and performing a second comparison process to compare the temperature information on the substrate detected at a second timing by the temperature detection unit with a second threshold value.

Staggered fluid ejection dies may include first, second and third fluid ejection dies, each of the dies having fluid feed passages between first and second long edges. And electrical interconnect may extend from a location proximate the first long edge of each of the fluid ejection dies. A temperature sensor may be supported proximate the second long edge of each of the fluid ejection dies. Each of the fluid ejection dies may omit temperature sensors proximate the first long edge.

A liquid ejection head has a plurality of nozzles and has a plurality of drive elements configured to cause the plurality of nozzles to eject liquid. A temperature sensor is configured to detect a temperature of the liquid ejection head. A heat generator generates heat when the plurality of drive elements is driven. A controller is configured to: perform a determining process of determining, based on a particular parameter indicative of a temperature difference, whether the printer is in a first state where the temperature difference is constant or in a second state where the temperature difference varies with time, the temperature difference being a temperature difference between the temperature detected by the temperature sensor and an actual temperature of the liquid ejection head; and control the plurality of drive elements based on a determination result in the determining process.

A liquid injection device includes a driving signal correction circuit correcting a reference driving signal based on a temperature detected by a temperature sensor. The driving signal correction circuit includes a first correction circuit that corrects injection pulses excluding a liquid drop injection speed-controlling injection pulse when the temperature detected by the temperature sensor is lower than or equal to a predetermined reference temperature, and a second correction circuit that corrects all of the injection pulses when the temperature detected by the temperature sensor is higher than the predetermined reference temperature.

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.

An embodiment of the present invention provides an ink jet printing apparatus including: a print head including a printing element array provided with printing elements each configured to generate thermal energy required to eject an ink, a supply flow channel provided along the printing element array and configured to supply the ink to the respective printing elements, an opening provided to the supply flow channel and configured to cause the ink to flow in, and heating units provided along the supply flow channel and configured to heat the ink inside the supply flow channel; and a heating control unit configured to carry out heating control of the heating units based on a heating pattern determined based on heating intensity distribution, the heating intensity distribution representing heating intensities corresponding to the respective heating units and representing the heating intensities corresponding to positions in a direction of the printing element array.

A drive signal may be determined to drive a printhead to a series of target temperatures during respective portions of a print pass by the printhead. Each of the target temperatures may be the greater of a temperature of the printhead caused by printing a quantity of printing fluid to be printed during the respective portion and a predetermined threshold temperature. A drive signal may be provided to warm the printhead to the series of target temperatures during the respective portions of the print pass.

Staggered fluid ejection dies may include first, second and third fluid ejection dies, each of the dies having fluid feed passages between first and second long edges. And electrical interconnect may extend from a location proximate the first long edge of each of the fluid ejection dies. A temperature sensor may be supported proximate the second long edge of each of the fluid ejection dies. Each of the fluid ejection dies may omit temperature sensors proximate the first long edge.

A drive signal may be determined to drive a printhead to a series of target temperatures during respective portions of a print pass by the printhead. Each of the target temperatures may be the greater of a temperature of the printhead caused by printing a quantity of printing fluid to be printed during the respective portion and a predetermined threshold temperature. A drive signal may be provided to warm the printhead to the series of target temperatures during the respective portions of the print pass.