Abstract: In control of a recording process in accordance with block driving, the driving timing of a pulse train is avoided from overlapping with each other between blocks, and a load imposed on a power supply during the operation is reduced. To that end, a recording apparatus includes a pulse generating unit for generating a driving pulse train consisted of a number (m) of pulses including a plurality of preheating pulses and one main driving pulse taking part directly in a recording process, the intervals between the (m) pulses being each not less than the total time of pulse widths of the (m) pulses, and a driving unit for dividing a plurality of recording elements into multiple blocks, and driving the recording elements in units of block to perform recording in such a manner that just before the second preheating pulse of the driving pulse train for one block, the first preheating pulse of the driving pulse train for the next block is applied.

Abstract: Energy applied to a heater for ejecting an ink is set to more than bubble generation threshold energy Eth and less than predetermined energy Eo, or to more than the predetermined energy Eo. Thereby, when an image to be printed is one of low ejection duty, an ejection where a bubble communicates with the atmosphere before the ink droplet separates from an ejection port (BTHJ ejection) is performed. On the other hand, when the image is one of high ejection duty, an ejection not communicating with the atmosphere as above (BUBBLE-JET ejection) is performed. As a result, an increase of ink mist due to satellites can be suppressed as a whole even if satellites are increased because of BTHJ ejection. When the ejection duty is high, generation of satellites themselves is reduced, thereby suppressing increase of ink mist.

Abstract: There is disclosed a substrate for use in an ink jet recording head, comprising on a base member an insulating film comprising an insulating material, a bubble-generating heater for generating heat required for bubble generation in ink, and a preheating heater for generating heat to be applied to a recording head for effecting recording on a recording medium, wherein the preheating heater is provided in a layer lower than that of the bubble-generating heater with interposition of the insulating film.

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: A recording method ejects ink by thermal energy produced by a heat generating element of a recording head in response to a drive signal. The method includes the step of controlling an amount of ejection of the ink by a temperature control for the recording head including at least heating of the recording head, when a temperature of the recording head is not higher than a predetermined first temperature. The method further includes the steps of controlling the amount of ejection of the ink by changing a waveform of the drive signal for ejecting ink in accordance with the temperature of the recording head when the temperature of the recording head is higher than the first temperature and not higher than a second temperature, and fixing the waveform of the drive signal when the temperature of the recording head is higher than the second temperature.

Abstract: An ink jet recording method includes supplying a driving signal of a phase, wherein the driving signal comprising at least first and second signal periods with a rest period therebetween; and supplying a driving signal of a phase which is different to provide the first or second signal overlaps with the rest period of the driving signal having the first mentioned phase.

Abstract: An ink jet printing apparatus is provided comprising a print cartridge including at least one resistive heating element in at least one ink-containing chamber having an orifice. The apparatus further includes a driver circuit, electrically coupled to the print cartridge, for applying to the resistive heating element warming and firing pulses separated by a delay period. The warming pulse causes the resistive heating element to warm a portion of the ink adjacent to the heating element and the firing pulse causes the resistive heating element to produce a vapor bubble in the chamber which causes a droplet of ink to be ejected from the chamber orifice.

Abstract: An apparatus and method for heating an ink jet printhead by using pass transistors to generate heat and warm the substrate of the printhead. The ink jet printhead has a plurality of ink jet printhead nozzle. Each nozzle is controlled by a circuit. The circuit includes a drive transistor that is electrically coupled to a heating resistor, an enable transistor and a plurality of pass transistors.

Abstract: A printing device having multiple printheads includes an acquisition device to obtain temperatures of the multiple printheads, a determination device which determines, based on the obtained temperature of one printhead, a target temperature corresponding to each other of the multiple printheads in order to maintain a predetermined output level relationship between an output level of the one printhead and an output level of each other of the multiple printheads, and an adjustment device to adjust the temperature of each other of the multiple printheads to the corresponding target temperature.

Abstract: An ink jet printhead includes a nozzle chamber having at least two fluid ejection apertures defined in a roof of the chamber; a moveable paddle vane located in a region of a first one of the fluid ejection apertures; an actuator mechanism attached to the moveable paddle vane and adapted to move the paddle vane in a first direction so as to cause the ejection of fluid drops out of the first fluid ejection aperture and to further move the paddle vane in a second, alternative direction so as to cause the ejection of fluid drops out of a second fluid ejection aperture. A method of manufacture of such a printhead comprises initially providing a silicon wafer having a circuitry wafer layer including electrical circuitry necessary for the operation of the actuator mechanism on demand. A trough is etched in the wafer to provide for an ink supply channel through a portion of the wafer.

Abstract: An ink jet head supplies an ejection heater arranged in a liquid path with a driving signal to impart heat energy to ink to thereby generate a bubble therein. The bubble is caused to communicated with the atmospheric air, and ink is ejected through an ejection outlet. A heat keeping circuit supplies the ejection heater with a driving pulse having a time width insufficient for causing ink to be ejected during non-printing period in an appropriate duty corresponding to the head temperature condition, thereby causing the ejection heater to generate heat to effect heat keeping on the head, whereby a low-cost thermal ink jet printing system is provided which does not entail a variation in ejection amount during printing.

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: Driving signal generating member for generating a first signal for drawing as meniscus at a nozzle aperture by smaller force as ambient temperature rises, a second signal for contracting a pressure generating chamber and ejecting an ink droplet and a third signal for restoring the contracted pressure generating chamber after an ink droplet is ejected by larger drawing force as ambient temperature rises is provided, speed at which the meniscus is moved toward the nozzle aperture is prevented from decreasing by setting force for drawing the meniscus before an ink droplet is ejected when temperature falls to a large value and the delay of filling the pressure generating chamber with ink is prevented by setting force for drawing the meniscus after an ink droplet is ejected to a small value and damping the residual vibration of the meniscus utilizing attenuation by increasing the viscosity of ink.

Abstract: When an image is to be printed by the so-called multi-scanning method where image data corresponding to one band width is printed by a printhead scanning for a plurality of times, masking is performed on the image data in each of the scanning operation, and an image is printed on the basis of the masked image data. In such manner, pixels printed in each scanning form an image corresponding to one-scanning data (one band width of the data). At the time of printing by multi-scanning, a preliminary pulse is added prior to a driving pulse which drives the printhead so that the density of the image printed by multi-scanning is not decreased. In addition to changing such driving condition of the printhead, the density of the image data outputted to the printhead may be changed.

Abstract: An inkjet printhead having a plurality of ink discharge nozzles that are served by respective ink supply conduits formed within a composite substrate includes ink discharge heaters respective to each of the nozzles, one or more substrate heaters for preheating an ink flow within the supply conduits and a plurality of resistors for monitoring the printhead quality during manufacture. The ink discharge heaters are in circuit with a first energy source connection and a common ground connection. The quality monitoring resistors are in series circuit with a second energy source connection and the common ground connection respective to the ink discharge heaters. At least one substrate heater is in circuit with a third energy source connection and the second energy source connection which, when the printhead is operatively connected for printing, is connected to ground.

Abstract: An ink jet printer having an ink jet head is disclosed. The ink jet head includes a plurality of electrothermal transducers for producing thermal energy used to eject ink from the ink jet head. The ink jet printer has a storing device which stores image data used to drive the electrothermal transducers and a switching device which switches energization periods for the electrothermal transducers in accordance with the image data stored in the storing device. The printer operates so that during a recording operation, when an image datum stored in the storing device instructs recording, the switching device supplies a first drive signal for preliminary ink heating and a second drive signal for ejecting the ink. When the image datum stored in the storing device is datum not instructing recording, the switching device supplies the first drive signal and does not supply the second drive signal.

Abstract: An ink jet recording apparatus records by supplying heat energy according to a drive pulse to an ink to form a bubble based on film boiling and ejecting the ink from a recording head onto a recording medium based on formation of the bubble. The ink jet recording apparatus includes a driver for supplying a pre-driving pulse that does not cause ink ejection and a main driving pulse that causes the ink ejection with a rest period between the two pulses for ejection of one ink droplet, and a rest period controller for controlling the rest period within a range where an amount of the ink ejection increases in accordance with an increase of the rest period. Controlling the rest period controls an amount of the ink ejection, with the rest period based on a temperature of the recording head. Also, a temperature of the recording head is obtained by calculating the energy input to the recording head by the supplied driving pulses.

Abstract: In a jet recording method, a recording material is placed in a path defined by a nozzle leading to an ejection outlet, and then heated by actuating a heater disposed within the nozzle to generate a bubble within the recording material, thus ejecting a droplet of the recording material out of the ejection outlet under the action of the bubble to be attached onto recording paper. As improvement, the recording material is pre-heated by actuating the heater before the heating for generating the bubble, and the generated bubble is caused to communicate with ambience. As a result, the ejection of the recording material droplet is stabilized without causing splash or mist.

Abstract: For each printhead nozzle, nozzle circuitry includes a warming transistor, drive transistor and heating resistor. To maintain a threshold temperature at the printhead, a warming pulse is sent from the warming transistor to the heating resistor of one or more nozzles when the temperature falls below a prescribed temperature. To fire a nozzle a firing pulse is output from the drive transistor to the heating resistor. The warming transistor is laid out as a segmented portion of the drive transistor layout area. No layout penalty is incurred by including the warming transistor for each nozzle. The source of a warming transistor is coupled in common to the source of a drive transistor. The drain of the warming transistor is coupled in common to the drain of the drive transistor. The gates are separate. The gates receive respective warming or firing control signals. The drains are coupled to the heating resistor.

Abstract: In a jet recording method, a normally solid recording material is placed in a heat-melted state within a nozzle and heated to generate a bubble therewithin by applying a bubble-generating heat energy, thereby ejecting droplets of the recording material out of the nozzle onto a recording medium. In the method, the ejection of the recording material droplets can be stabilized by applying prior to the bubble-generating heat energy a preheating energy which decreases continuously or discontinuously.

Abstract: An ink-jet recorder is disclosed which has an arrangement of a plurality of heat-generating elements, drivers for driving the heat-generating elements, and a drive circuit for controlling the drivers according to image data, wherein the drive circuit includes; a split-block drive circuit that divides the plurality of heat-generating elements into a plurality of blocks, and drives the heat-generating elements on a block-by-block basis in a time-sharing manner, and a data retaining circuit for retaining print data; and the split-block drive circuit that; drives each of the blocks of the heat-generating elements at printing operations, using a pre-pulse during which ink is not squirted and a main pulse during which ink is squirted; and drives another group of heat-generating elements differing from the currently-driven group of heat-generating elements, during intervals between the pre-pulse and the main pulse.

Abstract: A method and apparatus for producing a thermal pulse for a drop on demand printer actuator. A varying voltage pulse is applied to a resistance heater forming part of the actuator, which generates time varying power in the resistance heater. The power varies with respect to time in a manner comprising:1) a pre-heating stage, which raises the temperature of the actuator, but is of insufficient total energy to actuate the printing actuator;2) a stage of increased power which rapidly raises the temperature of the actuator to the required temperature for operation;3) a stage of decreased power, which is less than the power in stage (b) but is sufficient to maintain the temperature of the temperature at the required temperature for operation;4) a stage of low or zero power, during which the temperature of the temperature rapidly falls below the required temperature for operation.

Abstract: A liquid recording apparatus ejects droplets of liquid onto a recording medium. The apparatus has multiple liquid emitters whose emissions are activated by multiple power pulses. The power pulses are controlled to maximize the number of emitters which can be simultaneously energized while keeping the instantaneous power usage within prescribed boundaries. The multiple emitters are organized into banks of emitters whose numbers are small enough that all emitters within a bank can receive a correct level of power simultaneously without exceeding capacity of a shared power source. A circuit interleaves the power pulses to the emitters so that no bank of emitters are receiving power at the same instant of time.

Abstract: An ink jet recording apparatus is disclosed in which ink is ejected onto a recording material, the apparatus including a recording head having an energy generating element for producing energy contributable to eject the ink onto the recording material; a recording head driving device for applying drive signals having a waveform to the energy generating element; a temperature detecting device for detecting a temperature relating to the recording head and for producing an output; a changing device for changing the waveform of the driving signals in accordance with the output of the detecting device; and a drive control device for fixing the waveform to a predetermined waveform when the recording material used is an OHP sheet.

Abstract: A print head of this invention has a plurality of heater boards, and each heater board has a plurality of heating resistors, driver circuits corresponding to the heating resistors, one shiftregister for inputting serial data, a data latch circuit for latching print data input from the shift register, a pre-heat data latch circuit for latching selection data of selecting one or several of pre-heat signals input from the shift register, and a pre-heat selection circuit for selecting one or a plurality of pre-heat signals in accordance with the selection data latched in the pre-heat data latch circuit. In a print operation, one or several of the plurality of input pre-heat signals are selected to pre-heat the heating resistors, and when a main heat signal is input thereafter, the heating resistors are driven in accordance with the print data latched by the data latch circuit, thus performing the print operation.

Abstract: A method of and apparatus for compensating printing heads which operate in thermal drop on demand printing modes for the effects of thermal lag includes a counter which provides a number representing the amount of elapsed time during a heater energizing pulse as a proportion of the entire pulse duration. The output of the counter is connected to a device which determines the power supply voltage required at the said elapsed time. This result is used to control a programmable power supply which is connected to the heater power supply of the print head. The device is preferably a lookup table stored in digital memory, containing a pulse waveform calculated using iterated transient finite element analysis of the thermal state of the nozzle during simulated operation.

Abstract: An apparatus having an ink-jet head has a time measuring unit, a recording unit, and a prefiring operation control unit. The time measuring unit is used to measure an elapsed time from execution of prefiring operations for the ink-jet head, and the recording unit is used to record whether or not printing nozzles disposed in the ink-jet head are operated. The prefiring operation control unit determines a number of prefiring operations in accordance with a measurement result obtained by the time measuring unit and operated conditions of the printing nozzles recorded in the recording means, and executes prefiring operations for the ink-jet head. Therefore, the apparatus is capable of executing prefiring operations often enough and sufficient for the actual operated conditions of the printing nozzles disposed in the ink-jet head, and thereby preventing ink from being consumed at enhanced rate by useless prefiring operations.

Abstract: An ink-jet printing apparatus can obtain good image quality and improve reliability by avoiding possibility of failure of the head. A target temperature, at which ejection of ink through an ink-jet printing head becomes the most stable is set. Also, a difference between the target temperature and an actual temperature of the ink-jet printing head is derived. When the difference is positive, the drive signal includes a pre-heating pulse and a main heating pulse having an interval therebetween. The pulse width or the interval is properly set. When the drive signal is negative, only the main heating pulse is included. When the absolute value of the difference is large, the pulse widths are set smaller. At this time, a drive frequency is lowered or a resting period at opposite end positions in the scanning directions is prolonged.

Abstract: For each printhead nozzle, nozzle circuitry includes a warming transistor, drive transistor and heating resistor. To maintain a threshold temperature at the printhead, a warming pulse is sent from the warming transistor to the heating resistor of one or more nozzles when the temperature falls below a prescribed temperature. To fire a nozzle a firing pulse is output from the drive transistor to the heating resistor. The warming transistor is laid out as a segmented portion of the drive transistor layout area. No layout penalty is incurred by including the warming transistor for each nozzle. The source of a warming transistor is coupled in common to the source of a drive transistor. The drain of the warming transistor is coupled in common to the drain of the drive transistor. The gates are separate. The gates receive respective warming or firing control signals. The drains are coupled to the heating resistor.

Abstract: A recording apparatus includes an ink jet recording head having plural ejection outlets and thermal energy generating elements provided for the respective ejection outlets; a limiter for defining a using range of the heat generating elements in accordance with image forming conditions, a recording head driver for supplying to the heat generating elements outside the using range defined by the limiter driving signals insufficient to eject the ink and for supplying to the heat generating elements in the using range defined by the limiter a driving signal sufficient to eject the ink in accordance with an image signal.

Abstract: An ink-jet printer for printing an imaging using an ink-jet head has a heater for holding the temperature of the ink-jet head above a predetermined temperature. The temperature of the ink-jet head is held above the predetermined temperature at the time of a recording operation. When the recording operation ends, elapsed time from the end of recording is measured and, when elapsed time attains a predetermined time, current fed to the header is stopped. From this point onward, the temperature of the ink-jet head is held at a temperature below that which prevails at the time of recording until the next recording operation begins.

Abstract: An ink jet recording apparatus includes a recording head for ejecting ink from ejection unit to cause a change in temperature in a recording period, a temperature keeping unit for maintaining a temperature of the recording head at a predetermined keeping temperature higher than an upper limit of a surrounding temperature range in which recording is possible, a temperature prediction unit for predicting an ink temperature in the ejection unit in the recording period prior to recording, and an ejection stabilization unit for stabilizing ink ejection from the ejection unit according to the ink temperature in the ejection unit predicted by the temperature prediction unit.

Abstract: A technique for controlling print quality in an inkjet printer by delivering synchronized heating, non-printing pulses and printing pulses to the ink firing resistors during print firing operations such as during the printing of a swath. A temperature of the printhead substrate is measured and compared against a reference temperature during printing operations. If the measured temperature is below the reference temperature, then the printhead substrate is heated during the printing operations to bring the substrate up to the reference temperature. The heating is done by delivering synchronized heating non-printing pulses and printing pulses to the ink firing resistors during selected print firing periods, wherein either the heating pulses or the printing pulses, but not both, occur during a selected print firing period. The heating pulses are logically OR-ed with the printing pulses to achieve the synchronization.

Abstract: The heater chip (1) of an ink jet printer (10) has two substrate-heater resistors (3a and 3b) powered by the same power supply (24) as are the nozzle heaters (5) on the chip. Printhead (12) carries chip (1) and moves across paper (16) alternately left-to-right followed by right-to-left. Operation is during the margin periods when the nozzle heaters are not in operation. The power supply is thereby efficiently utilized.

Abstract: When a thermal inkjet print cartridge operates to eject ink, three things happen at once: (1) heating by the heating resistor with flow of heat into the ink chamber; (2) cooling by heat drain toward the reservoir, print cartridge body and to ambient; and (3) cooling by carrying away of heat in the ink drops and replacement by cooler ink from the reservoir. The present invention is a method of detecting a depleted ink supply by monitoring the temperature of the printhead substrate with a temperature sensitive resistive trace on the printhead surface. When the print cartridge is warmed with warming pulses to a temperature higher than its normal operating temperature: and then firing pulses are implemented to eject ink, the temperature measured by the thermal sense resistor will decrease if the print cartridge is ejecting its normal, or nearly normal, amount of ink. If the print cartridge is ejecting less than its normal amount of ink the temperature will decrease less, stay the same, or even increase.

Abstract: A recording apparatus for recording an image on a recording material includes a heat generating element for controlling a temperature of a recording head, a driver for driving the heat generating element to generate heat, and control circuitry for controlling the driver to generate heat from the heat generating element with plural steps with a predetermined heat generating period, after completion of a recording operation by the recording head.

Abstract: Disclosed is a method of determining imminent ink exhaustion in a thermal inkjet print cartridge based on the discovery that ink drop volume falls at a faster rate at high frequency firing rates than at low frequency firing rates as ink supply diminishes. The method includes warming the print cartridge printhead and ink to a predetermined temperature; then operating the print cartridge printhead at a first firing frequency to eject a volume of ink, said operating step including heating the ink and printhead, carrying away heat in the ejected volume of ink, and conveying a volume of cooler ink to the printhead to replace the ejected volume; and monitoring a first temperature change from the predetermined temperature.

Abstract: A preparatory head drive method for an ink jet printer having heads each including a plural number of nozzles. In the method, a discharging, preparatory drive method for effecting the head temperature rise by driving the nozzles so as to discharge ink and a heating, preparatory drive method for effecting the same by driving the nozzles to such an extent as not to discharge ink are alternately executed.

Abstract: The volume of drops ejected from thermal ink jet printheads varies with the temperature of the printhead. The variation in drop volume degrades print quality by causing variations in the darkness in black and white text, the contrast of gray scale images, and variations in the chroma, hue, and lightness of color images. The present invention reduces the range of drop volume variation by reducing the range of printhead temperature variation during the print cycle by keeping the printhead temperature above a reference temperature. When the printhead temperature falls below the reference temperature during a print cycle the printhead is heated with nonprinting pulses.

Abstract: An ink jet recording apparatus wherein a CPU checks the number of recording heads mounted on a carriage, sets a recording mode based on the number of recording heads, determines a combination of a drive frequency and a drive pulse width in accordance with the recording mode, sets drive pulse width data to a head controller, and heats the recording head or heads by a preliminary drive based on the set drive frequency and pulse width.

Abstract: A liquid-discharge recording apparatus such as an ink-jet printer comprises: a liquid-discharge recording unit having an emission energy generating device including an electrothermal energy converting device which can heat a recording liquid such as an ink to form liquid droplets in response to an electrical signal, in which this recording unit emits the liquid droplets and deposits them on a recording paper and thereby recording thereon; a recording unit control circuit which can set and supplies the electrical signal to form the liquid droplets to the emission energy generating device in response to a recording signal; and an emission controller for setting the electrical signal to form the liquid droplets to the recording unit control circuit when a power supply is turned on, thereby allowing the recording unit to and emit the liquid droplets in accordance with an environmental condition such as a temperature of the recording liquid.

Abstract: A method for operating a thermal ink jet printer including a printhead having ink firing heater resistors responsive to pulses provided to the printhead. Warming voltage pulses are applied to the printhead to warm the printhead to a temperature that is at least as high as a temperature that would be produced pursuant to ink firing pulses of a predetermined voltage, a predetermined pulse width, and a predetermined pulse frequency. A continuous series of ink firing pulses are then applied to the printhead, starting with a pulse energy substantially equal to the predetermined reference pulse energy and a pulse frequency equal to the predetermined pulse frequency, and then incrementally decreasing the pulse energy of the ink firing pulses. The temperature of the printhead is repeatedly sampled while the ink firing pulses are applied to the ink firing resistors to produce a set of temperature samples respectively associated with the decreasing pulse energies.

Abstract: An ink jet recording apparatus has a recording head provided with a plurality of ink discharging openings, ink paths leading to the ink discharging openings and an ink chamber commonly connected to the ink paths. Each ink path has a recording thermal energy generating element for causing film boiling of ink in the ink path so as to form a bubble of the ink vapor thereby discharging an ink droplet from the discharging opening. In order to recover from any ink discharging failure caused by bubbles stagnating in the ink paths, the recording thermal energy generating element can be driven in a specific driving condition with a smaller thermal energy input rate than in the recording operation. Tiny bubbles generated in each ink path as a result of the driving form a comparatively large void with which at least a part of the ink in each ink path is replaced so that stagnant bubbles are merged in the void and, hence, extinguished.

Abstract: A temperature control circuit regulates temperature in an ink-jet print head. The control circuit includes a thermal sensor mounted on the print head to measure its temperature and a temperature level detector to determine whether the measured print head temperature exceeds a threshold temperature. The temperature level detector outputs a first signal when the measured print head temperature exceeds the threshold temperature and a second signal when the measured print head temperature does not exceed the threshold temperature. The control circuit also has first logic circuitry to output warming pulses upon receipt of the second signal. The warming pulses have energy insufficient to deposit an ink drop from the print head. Second logic circuitry is configured to output warming pulses to non-selected nozzles of the print head and firing pulses to selected nozzles. In this manner, the print head is automatically warmed via the warming pulses so long as the print head temperature is below a prescribed level.

Abstract: A multiple-orifice phase-change ink-jet print head (28, 44) is heated by a composite laminate heater (29, 58) having multiple heating zones (31-31K, Z1-Z28) spanning the X- and Y-directions of the print head. The print head has multiple rows of ink-jet orifices (34, 46) spread across its face in the Y-direction with the ink in each orifice in each row requiring substantially the same temperature to ensure a uniform jetting velocity from every orifice. In one embodiment, the print head is in fluid communication with a thermally massive multicolor ink reservoir (52) that conducts heat through a region of contact (92) with the print head. A rotating drum (32), spaced across a gap (90) from the print head, draws air through the gap thereby cooling the print head differentially in the Y-direction. Radiation and convection are further thermal transfer mechanisms that contribute to a nonuniform temperature throughout the print heads.