Abstract: A problem that occurs with inkjet printers having a microelectromechanical thermal inkjet printhead is that the dot print size during the initial operation of the printer is inconsistent with the dot print size produced after the printer has reached an equilibrium temperature. In order to address this problem a method is described that involves applying a number of heating pulses to nozzles of the printhead before commencing a print job. The heating pulses are of sufficient duration to warm ink within the nozzles but are limited so that they do not cause ink ejection.

Abstract: An inkjet recording apparatus has a structure in which, when a recording-interruption operation of a recording head such as discharge-recovery processing is performed during an image-forming operation, a recording downtime is measured, and the recording head is heated in accordance with the length of a recording downtime so as to prevent occurrence of differences in optical densities and colors of an image before and after the recording-interruption operation.

Abstract: To provide a liquid discharger and a method to discharge liquid in which lowering of the precision of the assembly and the discharge accuracy of the high-viscosity liquid caused by thermal deformation, such as thermal expansion, is suppressed when the discharge heads of the inkjet apparatus are heated to accurately discharge the high-viscosity liquid, a liquid discharger having discharge heads to pressurize functional liquid contained in cavities communicating with nozzles and discharge the functional liquid from the nozzles, a mounting plate having openings to mount the discharge heads, a tank to contain the functional liquid discharged from discharge heads, and a liquid supply channel to supply the functional liquid from the tank to the discharge heads, the discharge heads mounted to the openings of the mounting plate at a same temperature as the temperature the functional liquid is discharged from the discharge heads.

Abstract: An inkjet printer includes a microelectromechanical printhead under the control of a printer processor. A plurality of feedback lines emanate from each of a number of segments of the printhead. Signals from the feedback lines are selectively conveyed to the processor by a tri-state bus. One of the feedback signals that is monitored by the processor is indicative of printhead temperature which is a parameter that affects ink viscosity and hence print quality. In response to variations in printhead temperature the processor is programmed to adjust the ink drop firing pulses that are delivered to the printhead in a compensatory manner.

Abstract: Disclosed is a liquid jetting device which includes: a liquid chamber for containing a liquid to be jetted out; an energy generation element for imparting energy to the liquid in the liquid chamber; and a nozzle for jetting out the liquid in the liquid chamber as a droplet by the energy generation element. In the liquid jetting device, a plurality of the nozzles are arrayed to constitute a head, and a plurality of the heads are arrayed in a direction orthogonal to the array direction of the nozzles to constitute a head array. In addition, the droplet jetted out from each of the nozzle in the head array is deposited on a recording medium to form a dot. Further, the jetting direction of the droplet jetted out from the nozzle can be deflected by controlling the manner in which the energy is imparted to the liquid by the energy generation element. Furthermore, an error in the deposition position of the dot due to an error in the position of the head in the head array is corrected.

Abstract: A droplet-jetting device having high jetting ability, which includes an actuator featuring a liquid chamber and a heater and a controller. The liquid chamber has an aperture for jetting droplets of an operation liquid which the liquid chamber accommodates. The heater provides thermal energy to the operation liquid and forms bubbles for droplet-jetting. The controller controls a driving signal, which is inputted to the heater. The driving signal includes a preparatory heating pulse signal, which corresponds to a preparatory heating energy for preparatory heating of the operation liquid, and a trigger pulse signal, which corresponds to a jetting thermal energy for bubble creation and growth. A power supplied by the preparatory heating pulse signal is smaller than a power supplied by the trigger pulse signal, and a heating duration by the preparatory heating pulse signal is longer than a heating duration by the trigger pulse signal.

Abstract: An inkjet printer for jetting ink of the optimal viscosity for image-recording during recording operation. The inkjet printer includes: a temperature sensor for detecting a temperature of the ink in a recording head; a heater for heating the ink in the recording head by generating heat; and a control unit for controlling the heater based on a result detected by the temperature sensor. In the control unit, a set value for defining a heating temperature of the heater is stored, and first factors including movement speed of a carriage and the number of times of movement of a carriage, and a first correction value corresponding to the first factors are stored as a first data table. The control unit specifies the first correction value from image information, corrects the set value based on the first correction value, and controls the heater for generating heat according to the corrected set value.

Abstract: A recording head comprises a plurality of recording elements for performing recording; a driving circuit for driving the plurality of recording elements; and a predetermined voltage generating circuit for generating a predetermined voltage to be applied to the plurality of recording elements from voltage supplied from outside. With the head thus structured, a desired voltage is generated in the interior of the head by use of the predetermined voltage generating circuit for performing recording, thus making it possible to prevent the voltage drop which may take place if the voltage is supplied from outside through a cable, as well as to prevent the durability of the heat generating elements from being damaged due to noises. It also becomes possible to set the voltage to be applied to the recording elements at an optimal value corresponding to the discharge voltage, hence stabilizing ink discharges efficiently.

Abstract: A printer comprising an inkjet printhead having an array of nozzles is provided. Each nozzle comprises a chamber for storing ink to be ejected, an aperture defined in a wall of the chamber, a thermal bend actuator for ejecting ink from the chamber through the aperture, a MEMS temperature sensor and drive circuitry for operating the thermal bend actuator. The drive circuitry is operable in two modes: a normal mode wherein drive signals to each actuator ejects ink from the corresponding chamber, and a preheat mode wherein drive signals to each actuator heats ink in the corresponding chamber but does not eject ink from the chamber. The preheat mode is selected by the printer if the MEMS temperature sensors sense that the ink is below a predetermined temperature threshold.

Abstract: This invention relates to a printer whereby ink is printed by being discharged as dots from a plurality of nozzles by means of pulses. To ensure high quality printed images it is necessary to ensuring that the size of all dots is consistent. Therefore there is provided a method and apparatus whereby before printing of any dots, the temperature of the ink in each nozzle is sensed by Tsense, and a pulse insufficient to fire the ink from the nozzle, yet sufficient to heat up the ink, is fired to each nozzle in the same sequence as the standard print cycle, and the temperature of the ink is sensed. This process is repeated until the required temperature of the ink is reached, and printing is then inititated.

Abstract: The present invention relates to an ink jet printing apparatus which sufficiently heats a head even in a low-temperature environment, which enables a proper image to be printed by stably ejecting ink, and which can be inexpensively and simply constructed. According to the present invention, if the detected temperature of a printhead is lower than a first heating threshold temperature, a heating mode in which the printhead can be heated is set before a printing operation. Further, when the heating mode is set and the detected temperature of the printhead is lower than a second heating threshold temperature, a heating unit heats the printhead. Consequently, even in a low-temperature environment, the heating operation keeps ink in a desired condition suitable for printing.

Abstract: A method of operation of an inkjet printhead within a predetermined temperature range to print an image, wherein the printhead temperature is measured and if the temperature is below a predetermined threshold, the printhead is heated by pulses of energy to a desired temperature above the predetermined threshold temperature before printing. The actuators are displaceable thermal actuators and heating is controlled such that the pulses of energy are insufficient to cause ejection of fluid from the printhead.

Abstract: An inkjet printhead with thermal bend actuators for ejecting ink from the nozzle apertures and drive circuitry for operating each thermal bend actuator in a normal mode wherein drive signals to the actuator ejects ink from the chamber, or a pre-heat mode wherein drive signals to the actuator heats ink in the chamber but does not eject ink from the chamber. The invention uses the drive signal to the bend actuator to generate heat to raise the temperature of the ink in the chamber, but controls the signal so that the actuator will not respond in a manner that will eject ink. After a brief pre-heat cycle, the drive circuitry can switch to normal operating mode and the bend actuators will eject ink for printing. With the ink temperature and viscosity within normal operating range, the print quality is not compromised.

Abstract: This invention provides an image printing apparatus in which, when the printhead temperature rises in driving the printhead at a high speed, the ink discharge amount is optimized in accordance with the temperature rise to achieve high-quality, high-efficiency printing. For this purpose, in an image printing system using a time division simultaneous driving method of grouping a predetermined number of printing elements into a plurality of blocks every predetermined number of printing elements and driving printing elements belonging to the same block at the same driving timing, if the printhead falls within a predetermined temperature range, droplets are discharged using all blocks to print an image. To the contrary, if the printhead reaches the predetermined temperature or higher, blocks to be used are restricted in accordance with the printhead temperature, the total number of droplets is decreased, and the amount of one droplet is increased to print an image.

Abstract: An ink/print media discriminating portion discriminates kind of ink to be used in an apparatus on the basis of information of kind of the ink or a printing medium input by a user. The discrimination information is fed to a thermal energy generation amount control portion. The thermal energy generation amount control portion sets a driving condition, such as a pulse width of a drive pulse or the like corresponding to the kind of the ink represented by the discriminated information, is set in a head driving portion.

Abstract: A method of operation of a fluid ejection printhead within a predetermined thermal range to print an image, wherein the printhead temperature is measured and if the temperature is below a predetermined threshold, the printhead is heated by pulses of energy to a desired temperature above the predetermined threshold temperature before printing. Where thermal bend actuators are used in the printhead, heating is controlled such that the pulses of energy are insufficient to cause ejection of fluid from the printhead and their duration is tuned in accordance with the fluid composition.

Abstract: In a liquid ejecting device having a head formed by a liquid ejecting portion or liquid ejecting portions arranged in parallel, the direction of ejected liquid is controlled for each liquid ejecting portion. In the head of the liquid ejecting device, heating resistors which are connected in series to one other in a liquid cell are arranged in parallel in a predetermined direction. The liquid ejecting device includes a main operation controller which performs control for ejecting liquid by supplying equal amounts of currents to the connected heating resistors, and a sub operation controller including a current-mirror circuit connected to a junction of heating resistors and its switching element. By using the current-mirror circuit and the switching element to allow a current to flow into or from a junction of the heating resistors, the amounts of currents supplied to the heating resistors are controlled and the direction of ejected liquid is controlled (changed).

Abstract: A series of enable trains are designed to provide a predetermined increment of heat to the heating element of a thermal ink jet printer printhead. The enable trains are stored in tabular form in memory according to printhead temperature. The printhead temperature is sensed during the printing cycle and read by the printhead controller. The controller selects a enable train from the table and applies it to the heating element. When subsequent cycles call for a change in the enable train, the current enable train is blended with the new enable train to provide an average increment of heat.

Abstract: A method of operation of a fluid ejection printhead within a predetermined thermal range to print an image, wherein the printhead temperature is measured and if the temperature is below a predetermined threshold, the printhead is heated by pulses of energy to a desired temperature above the predetermined threshold temperature before printing. Where thermal bend actuators are used in the printhead, heating is controlled such that the pulses of energy are insufficient to cause ejection of fluid from the printhead.

Abstract: Prompt ink-temperature control can be performed without increasing the capacity of a power supply. In an ink-jet recording apparatus performing recording by causing an ink-jet recording head for performing recording by discharging ink to perform scanning on a recording medium, the temperature of ink is raised to a predetermined temperature by applying a pulse so short as not to cause ink discharge to a discharge heater for discharging the ink, and using a sub-heater for heating the ink. Parameters (short-pulse conditions) of a short pulse to be applied to the discharge heater are changed in accordance with the states of operations of a carriage motor for causing the recording head to perform scanning, and a sheet feeding motor for conveying the recording medium.

Abstract: In an ink-jet printing apparatus which includes a plurality of printing heads each having an array of ink discharging elements, preliminary discharge of driving the elements of at least one printing head is performed a predetermined number of times as a unit in performing preliminary discharge of discharging ink irrelevant to printing. The printing head for which the preliminary discharge is to be performed is switched in a predetermined cycle. In performing the preliminary discharge and switching of the printing head are so controlled as to perform preliminary discharge a desired number of times for all the elements of the printing heads by repeating the cycle.

Abstract: A method of operation of a fluid ejection printhead within a predetermined thermal range to print an image, wherein the printhead temperature is measured and if the temperature is below a predetermined threshold, the printhead is heated by pulses of energy to a desired temperature above the predetermined threshold temperature before printing. Where thermal bend actuators are used in the printhead, heating is controlled such that the pulses of energy are insufficient to cause ejection of fluid from the printhead and their duration is tuned in accordance with the fluid composition.

Abstract: A driving circuit drives an ink jet print head in a printing device. The ink jet print head has ink jet cells and heating elements corresponding to the ink jet cells. The driving circuit has a driving signal generator that provides two different driving signals to heat the ink jet cells. The first driving signal heats cells intended for jetting ink with sufficient energy so that they do jet ink. The second driving signal heats cells not intended for jetting ink with insufficient energy so that they are heated without jetting ink.

Abstract: An jet recording apparatus, which records on a recording medium by discharging ink form a recording head, is provided with at least two electrothermal converting elements each having different amount of heat generation, and driven each individually, which are arranged in the ink flow path communicated with the discharge port of the recording head along the ink flow path each in different distance to the discharge port, and when the pre-discharge is performed without participating in recording, driving signals needed for discharging ink are supplied to the electrothermal converting element on the side near to the discharge port subsequent to being supplied to the electrothermal converting element on the side away from the discharge port.

Abstract: A method of operation of a fluid ejection printhead within a predetermined thermal range so as to print an image, wherein the printhead temperature is measured and below a predetermined threshold, the printhead is heated to a desired temperature before printing. Where thermal bend actuators are used in the printhead, heating is controlled so as to be insufficient to cause ejection of fluid.

Abstract: A print head apparatus capable of temperature sensing is provided. The print head apparatus includes an ink ejector coupled to an enabling signal and a selection signal for selecting the ink ejector. The ink ejector includes a nozzle, a heating module for selectively heating ink in the ink ejector so that ink droplets are ejected from the nozzle, and a temperature sensing module for selectively producing a measured temperature signal indicative of a temperature of the ink in close proximity to the nozzle. When the enabling signal is active, and the selection signal is active and indicates that the ink ejector is selected, the heating module heats up the ink in the ink ejector so that the ink droplets are ejected from the nozzle. When the selection signal is active and indicates that the ink ejector is selected, the temperature sensing module outputs the measured temperature signal indicative of the temperature of the ink in close proximity to the nozzle.

Abstract: A printing head has a plurality of heater boards, each of which includes a shift register to which printing data and selection data for selecting preheating pulse signals are applied as inputs, a latch circuit for latching the printing data, a selection-data latch circuit for latching the selection data, a selection circuit for selecting any one of a plurality of preheating pulse signals inputted in accordance with the latched selection data, and a plurality of heating resistors driven by the printing data or preheating pulse signals. Correction data, obtained by a head correcting apparatus, for performing printing at an average density by correcting the characteristics of each heater board is stored in a memory of the printing head. A printing apparatus decides the selection data in accordance with the correction data and sets the selection data in the selection-data latch circuit.

Abstract: The invention relates to an inkjet temperature regulation controller that includes a time base circuit adapted to generate a clock signal and a head temperature sampler adapted to generate head temperature data by sensing print head temperature responsive to the clock signal. A preheat data generating circuit is adapted to translate the head temperature data into head preheat temperature data. A preheat data delivering circuit is adapted to provide the preheat temperature data to at least one preheating element. A monitor circuit is adapted to generate statistical data according to the head temperature data. The preheat data generating circuit receives updated head preheat temperature data responsive to the statistical data.

Abstract: A signaling method for a pen driver circuit interface is embodied in a signal interface between a controller circuit and a pen driver circuit for a printer. At least one signal of the interface is omitted; and the pen driver circuit is modified to process a combination of signals including at least one of the signals on the signal interface to provide information pertaining to the at least one omitted signal. According to a preferred method, the combination of signals are processed when data is not being transferred via the signal interface to provide a pen firing control signal for the printer such as a warm enable signal or a fire enable signal.

Abstract: The present invention includes an embodiment for optimizing the temperature operating range for a thermal inkjet printhead using ink over large print swaths. In general, this embodiment includes receiving the temperature of a digital temperature sensor (DTS) before printing begins, comparing this temperature with the set point for printing, initiating heating elements if the temperature is below the printing threshold, and turning off those heating elements when the threshold temperature of the die has been reached. The method and process minimizes thermal excursions, either above or below the set point for the production of ink droplets, and maintains an approximate isothermal environment for operation.

Abstract: A printer having storing means storing time information indicating the time at which cleaning operations were last performed, with the initial value of time information stored in the storing means being set to a time later than the shipment of the printer. Elapsed time between the time information stored in the storing means and the current time is calculated when a user gives the printer an instruction to start printing operations. The printer performs suitable cleaning operations for a case wherein the calculated value of the elapsed time is negative.

Abstract: A method and apparatus prevents banding defects caused by drop mass variations in an ink jet printer. The ink jet printer uses different pre-pulse sequences for drop ejection depending on print head temperature. Each of the different pre-pulse sequences is associated with a corresponding temperature range. Boundaries between adjacent temperature ranges are separated by critical temperatures. A determination is made as to whether a change in the print head temperature constitutes, or is part of, a temperature change that exceeds a predetermined threshold change amount, prior to determining whether to change the pre-pulse sequence.

Abstract: An inkjet printhead having a series of nozzles for the ejection of ink wherein each said nozzle has a rim formed by the deposition of a rim material layer over a sacrificial layer and a subsequent planar removal of at least said rim material layer so as to form said nozzle rim.

Abstract: In a normal record mode, a non-heat mode such that a non-ejecting pulse for heating is not supplied when the image recording is not executed is set. In a continuous magnify-record mode, a heat mode such that the non-ejecting pulse for heating is supplied when the image recording is not executed is set. Thus, a non-uniformity of an image density at the start and end of the recording can be suppressed and a reduction of the life of the head can be minimized.

Abstract: A recording control method and a recording apparatus in which high accuracy in the position of a discharged liquid droplet is obtained irrespective of changes in the temperature of a recording head are provided. In a liquid discharging method in which a bubble is generated by supplying ink (a liquid) with thermal energy, and the generated bubble is caused to communicate with the atmospheric air, by controlling a driving signal so that a discharging state in which a part of the ink to be discharged falls even if the temperature of the recording head changes, the direction of ink discharge can be stabilized.

Abstract: An ink jet recording apparatus includes an ink jet recording head provided with a discharge port for discharging ink, an ink flow path communicating with the discharge port, and at least two heat generating elements provided in the ink flow path along the direction thereof, wherein the ink is pigment-based ink and the recording head comprises drive signal supply means for varying the supply timing of drive signals to the plural heat generating elements for ink discharge in such a manner that the drive signal is at first given to the heat generating element at the side of the discharge port at room temperature and the supply timings to the plural heat generating members become simultaneous or closer thereto with an increase in the temperature of the recording head.

Abstract: A recording head records data by correcting a variation among recording elements without significantly increasing a size of a substrate of the recording head. The recording head includes a plurality of heat generating elements and a circuit for energizing the heat generating elements in accordance with record data to record data. Selection information for selecting one of a plurality of pre-heat pulse signals is non-volatilly stored in a ROM and one of the pre-heat signal pulses applied to an input terminal is selected in accordance with the selection information stored in the ROM to pre-heat the heat generating elements.

Abstract: An ink jet recording apparatus includes an ink jet recording head provided with a discharge port for discharging ink, an ink flow path communicating with the discharge port, and at least two heat generating elements provided in the ink flow path along the direction thereof, wherein the ink is pigment-based ink and the recording head comprises drive signal supply means for varying the supply timing of drive signals to the plural heat generating elements for ink discharge in such a manner that the drive signal is at first given to the heat generating element at the side of the discharge port at room temperature and the supply timings to the plural heat generating members become simultaneous or closer thereto with an increase in the temperature of the recording head.

Abstract: An ink jet recording apparatus is disclosed in which a bubble is created in ink by thermal energy generated in response to a drive signal applied to a heater, and the ink is ejected onto a recording material by expansion of the bubble. The recording apparatus includes a driving device and a changing device. The driving device applies a plurality of driving signals to the heater for each ink droplet ejection. The driving signals include a first driving signal for increasing a temperature of the ink adjacent the heater without creating the bubble, and a second driving signal after the first drive signal for ejecting the ink. An interval is provided between the first and second drive signals. The changing device changes a width of the first drive signal to adjust an amount of ejected ink. The interval is not shorter than 2.6 microseconds and the second drive signal has a constant width.

Abstract: This present invention is embodied in a printing system having a printhead assembly with a warming circuit for controlling the temperature of an inkjet printhead. The printing system includes a controller, a power supply and a printhead assembly having a memory device and a distributive processor integrated with an ink driver head. The distributive processor, the warming circuit and a sensor on the printhead assembly can regulate the temperature of the printhead assembly based on sensed and predefined operating information to maintain the printhead assembly within a desired temperature range.

Abstract: A method and apparatus for controlling the volume of ink droplets ejected from printhead nozzles over a larger printhead operating temperature range. Each nucleating electrical pulse applied to the heating elements in the printhead to eject an ink droplet is preceded by a plurality of non-nucleating pre-pulses. Based upon the printhead temperature sensed, a controller selects the pre-pulse width and time width between pre-pulses from a look-up table.

Abstract: A signaling method for a pen driver circuit interface is embodied in a signal interface between a controller circuit and a pen driver circuit for a printer. At least one signal of the interface is omitted; and the pen driver circuit is modified to process a combination of signals including at least one of the signals on the signal interface to provide information pertaining to the at least one omitted signal. According to a preferred method, the combination of signals are processed when data is not being transferred via the signal interface to provide a pen firing control signal for the printer such as a warm enable signal or a fire enable signal.

Abstract: An ink jet print head is formed of a silicon substrate that includes integrated circuits formed therein for controlling operation of the print head. The silicon substrate has a series of ink channels formed therein along the length of the substrate. An insulating layer or layers overlying the silicon substrate has a series of nozzle openings or bores formed therein along the length of the substrate and each nozzle bore communicates with a respective ink channel. A primary heater element is associated with each nozzle bore for asymmetrically heating the ink in the nozzle bore. A secondary heater element is provided upstream of the primary heater element and formed in the insulating layer to preheat ink just prior to entry of the ink into the nozzle bores.

Abstract: A printing head has a plurality of heater boards, each of which includes a shift register to which printing data and selection data for selecting preheating pulse signals are applied as inputs, a latch circuit for latching the printing data, a selection-data latch circuit for latching the selection data, a selection circuit for selecting any one of a plurality of preheating pulse signals inputted in accordance with the latched selection data, and a plurality of heating resistors driven by the printing data or preheating pulse signals. Correction data, obtained by a head correcting apparatus, for performing printing at an average density by correcting the characteristics of each heater board is stored in a memory of the printing head. A printing apparatus decides the selection data in accordance with the correction data and sets the selection data in the selection-data latch circuit.

Abstract: A control circuit for driving a print head of a printing apparatus is disclosed. The print head has a plurality of heating elements and a plurality of ink chambers. Each ink chamber stores ink and has a nozzle. The control circuit includes a thermometer for measuring a temperature of the ink chambers, and a processor for generating a heating signal according to printing data transmitted from the printing apparatus to drive heating elements to heat ink chambers corresponding to nozzles which will jet ink. The processor also generates a pre-heating signal to drive the heating elements according to the temperature measured by the thermometer. When necessary, the processor will generate the pre-heating signal in addition to generating the heating signal so as to provide additional energy to drive the heating elements corresponding to the nozzles which will jet ink.

Abstract: The invention relates to an inkjet temperature regulation controller that includes a time base circuit adapted to generate a clock signal and a head temperature sampler adapted to generate head temperature data by sensing print head temperature responsive to the clock signal. A preheat data generating circuit is adapted to translate the head temperature data into head preheat temperature data. A preheat data delivering circuit is adapted to provide the preheat temperature data to at least one preheating element. A monitor circuit is adapted to generate statistical data according to the head temperature data. The preheat data generating circuit receives updated head preheat temperature data responsive to the statistical data.

Abstract: A printhead with a comparatively simple construction, which contributes to reducing the cost of the entire system and development work, effectively utilizes essential constituent devices of a logic circuit of the printhead such as a shift register, while omitting control on the printing apparatus side, and individually performs stable print operation, while suppressing variation of energy inputted to heat generators due to voltage drop by parasitic resistance. A printing apparatus incorporates the printhead. The printhead has a counter which counts the number of simultaneously-driven heat generators, which always changes in accordance with image data, based on externally-inputted image data and block selection signal, and a modulator which modulates the pulse width of a drive signal applied to the simultaneously-driven heat generators based on a value obtained from counting by the counter.

Abstract: A printing head has a plurality of heater boards, each of which includes a shift register to which printing data and selection data for selecting preheating pulse signals are applied as inputs, a latch circuit for latching the printing data, a selection-data latch circuit for latching the selection data, a selection circuit for selecting any one of a plurality of preheating pulse signals inputted in accordance with the latched selection data, and a plurality of heating resistors driven by the printing data or preheating pulse signals. Correction data, obtained by a head correcting apparatus, for performing printing at an average density by correcting the characteristics of each heater board is stored in a memory of the printing head. A printing apparatus decides the selection data in accordance with the correction data and sets the selection data in the selection-data latch circuit.

Abstract: An ink jet recording apparatus, in which thermal energy is applied to ink in accordance with a driving signal applied to a heater to produce a bubble, by which ink is ejected onto a recording material, includes a driver for applying a plurality of driving signals to the heater for one ejection of one ink droplet. The driving signals comprise a first driving signal not ejecting the ink and a second driving signal for ejecting the ink, the second driving signal being applied after a rest period after the first driving signal. The apparatus further includes a controller for changing an amount of ink ejected by changing a length of the rest period and changing the first driving signal. The controller effects its changing operation in a first changing region in which the rest period is changed without changing the first driving signal and in a second changing region in which a length of the first drive signal is changed.

Abstract: A method and apparatus of warming a printhead with a heat sink using prepulsing is provided. A temperature of the printhead may be measured and then using predetermined data, an amount of prewarming of the printhead may be determined based on the measured temperature. The printhead may be prewarmed by prepulses based on the determined amount of prewarming prior to printing a swath of data. The swath of data may then be printed and the temperature of the printhead may again be measured to determine a subsequent temperature and amount of prewarming. The printhead may again be prewarmed prior to printing subsequent swath by applying prepulse signals which are determined based on the subsequent temperature of the printhead. The thermal mass of the heat sink may be used for the advantage of minimizing the amount of required prewarming, and therefore, maximizing the productivity, when the ambient temperature is low.