Abstract: The present invention relates to an ink jet recording apparatus including a recording head including a plurality of energy generation elements configured to generate thermal energy. The ink jet recording apparatus includes a specification unit and a control unit. The specification unit specifies a pulse width upper limit value of a prepulse during a recording operation based on a minimum pulse width by which ink is discharged by applying a drive pulse to the energy generation elements and a temperature of the recording head during the recording operation. The control unit controls the energy generation elements to be driven using a drive pulse of a prepulse with a pulse width equal to or less than the pulse width upper limit value.

Abstract: A capacitive load drive circuit includes first and second capacitive loads, first and second connection path selection sections, and a voltage generation section. The first capacitive load and the second capacitive load are configured to charge and discharge in accordance with a drive signal. The first connection path selection section is configured to selectively supply a plurality of voltages to the first capacitive load, the first connection path selection section being arranged so as to correspond to the first capacitive load. The second connection path selection section is configured to selectively supply a plurality of voltages to the second capacitive load. The second connection path selection section is arranged so as to correspond to the second capacitive load. The voltage generation section is configured to generate and supply the voltages shared by the first connection path selection section and the second connection path selection section.

Abstract: An image forming apparatus includes: and a unit that electrically shuts off a pressure generating unit corresponding to a nozzle ejecting no droplet, from a drive waveform generating unit for a period of a time Tb satisfying a relation Tb?T2, and that applies, at a time after the shutoff, a voltage of a potential V1 to the pressure generating unit, where a potential serving as a reference for the drive waveform is denoted as V1, a minimum potential difference from the potential V1 required to displace a pressure generating unit to vibrate a meniscus with ejecting no liquid droplet from a nozzle is denoted as ?V2, a time required for a potential to drop by the potential difference ?V2 due to self-discharge after a pressure generating unit is charged to a predetermined potential is denoted as T2.

Abstract: A method of producing droplets from a nozzle provided on a material layer, the method comprising the steps of supplying liquid to an inner end of an array of nozzles, the nozzles being split into M groups of one or more nozzles, generating one or more firing signals, each firing signal causing sufficient movement of a group of nozzles relative to the liquid such that liquid is projected as droplets from the outer face of the respective nozzles, generating one or more sub-firing signals associated with each group of nozzles, the one or more sub-firing signals causing movement of the group of nozzles which is insufficient to project liquid from the nozzles, the sub-firing signals of adjacent groups having a non-zero phase relationship, wherein the sub-firing signal(s) of at least one group of nozzles is independent of the firing signal(s) associated with that group.

Abstract: The power supply includes a transformer for generating a first output voltage by a first secondary winding, and a superimposing voltage by a second secondary winding, and a driver. Furthermore, the circuit includes first and second rectifying and smoothing circuits for respectively rectifying and smoothing the first output voltage and superimposing voltage, and an adder for adding the rectified and smoothed superimposing voltage on the rectified and smoothed first output voltage to output a second output voltage. The first and second output voltages are fed back respectively by DC coupling, the fed-back first and second output voltages are respectively adjusted by first and second feedback factors, and the adjusted feedback components are combined and amplified to be applied to the driver for PWM-control.

Abstract: An object of the present invention is to provide a liquid ejection head capable of suppressing the capture of bubbles into the liquid ejection head including ejection ports having different opening areas so as to satisfactorily fill a liquid channel and the ejection ports with liquid. In order to achieve the object, the liquid ejection head according to the present invention includes a liquid supply port communicating with a plurality of kinds of ejection ports, and further, a defoaming opening communicating with another ejection port except an ejection port having a large opening area out of the plurality of kinds of ejection ports via a defoaming channel.

Abstract: Provided are an inkjet printing apparatus, whereby pulse drive periods and a pause period can be adjusted so as to fall within predetermined periods, while the volume of ink to be ejected is ensured, and a heat generating element driving method therefor. For the inkjet printing apparatus, a pulse signal drive period for a pulse driven previously, a pulse signal drive period for a pulse driven subsequently and a pause period are set to perform ejection of ink droplets one time. When the ejection period exceeds the threshold value, the pulse signal drive period for the pulse driven subsequently and the pause period are reduced to adjust the ejection period to be equal to or lower than a threshold value.

Abstract: An image forming apparatus includes a head drive control unit configured to generate a drive waveform including drive pulses in time series, select one or more drive pulses from the drive waveform according to a droplet size, and provide the selected drive pulses to a pressure generation unit configured to generate a pressure for pressurizing a liquid in a liquid chamber. The drive waveform includes a pulling-in waveform element to be selected first. The pulling-in waveform element allows the individual liquid chamber to expand to an expanding state smaller than before start of contraction for droplet ejecting. The drive pulse includes an expanding waveform element that allows the liquid chamber having expanded in the pulling-in waveform element to expand to the expanding state before start of contraction for droplet ejecting, and a contracting waveform element that allows the liquid chamber to contract.

Abstract: There is provided a printing apparatus comprising: a printhead; a recovery mechanism for the printhead; a jetting failure detector; an operation history memory; a detection condition memory, the jetting failure detector; and a controller. The controller in configured to control the printing apparatus to: determine whether or not the operation history of the printhead conforms to the first condition value; determine whether or not the jetting failure is present, in a case that, the operation history conforms to the first condition value; cause the recovery mechanism to perform the recovery process, in a case that, the jetting failure is present; and cause the detection condition memory to store the second condition value smaller than the first condition value as a new first condition value, in a case that the jetting failure is present.

Abstract: An image forming apparatus includes: a liquid droplet discharge head; a pressure generator; and a driving waveform generator configured to generate a driving waveform including a plurality of pulse units for driving the pressure generator for discharging a liquid droplet. The pulse unit includes one or more first pulses, and one or more second pulses arranged after the first pulses for discharging a liquid droplet. The second pulse has a pulse width that is set in advance to generate a resonance with the liquid droplet discharge head. The first pulse has a pulse width different from the pulse width of the second pulse.

Abstract: There is provided an ink jet recording method for printing a pigment in which a pigment printing ink composition including at least pigment as a colorant is discharged from a nozzle opening as an ink droplet having an amount of the ink of the ink droplet of 9 ng or less with an average discharging speed V of 5 m/s or greater at a distance in the range of 0.5 mm to 1.0 mm in the direction from the nozzle opening to cloth, and whereby the pigment printing ink composition is adhered to the cloth.

Abstract: A liquid ejecting apparatus includes a piezoelectric element, a nozzle that ejects a liquid in association with the driving of the piezoelectric element, a driving signal generation unit that generates a driving signal for driving a plurality of the piezoelectric elements, and a residual vibration detection unit that detects residual vibration generated by the driving of the piezoelectric element. The driving signal includes an ejection pulse for ejecting a liquid, a first vibration damping pulse that suppresses residual vibration generated by the ejection pulse, a second vibration damping pulse which is a pulse different from the first vibration damping pulse and suppresses residual vibration generated by the ejection pulse, and an inspection pulse for detecting the residual vibration signal.

Abstract: An inkjet recording apparatus includes a head driving section that includes a drive pulse generator and a selector. The drive pulse generator generates, as the waveforms of drive voltage to be applied to the piezoelectric elements, a plurality of drive waveforms that includes an ink-ejection drive waveform defined according to the number of times of ink ejection to be made from the corresponding nozzle, and a reset waveform which causes greater drawing of the meniscus in the corresponding nozzle than by the ink-ejection drive waveform. With respect to each nozzle, the selector selects to apply which of the drive waveforms generated by the drive pulse generator or not to apply any of the drive waveforms to the corresponding piezoelectric element.

Abstract: A printer controller outputs plural drive signals including respective series of drive pulses, the timing points of which are different from one another, to a head control unit side, and outputs a multiplexed signal resulting from multiplexing change signals corresponding to the respective drive signals to a head control unit side, and the head control unit includes a control signal demultiplexing unit which demultiplexes the multiplexed signal into the change signals corresponding to respective nozzle rows, and an actuator control unit which, on the basis of each of the demultiplexed change signals, selects one of the drive pulses included in one of the drive signal which corresponds to the demultiplexed change signal, and applies the selected drive pulse to a piezoelectric element included in one of the nozzle rows which corresponds to the drive signal corresponding to the demultiplexed change signal.

Abstract: A printing apparatus includes a control unit configured to perform control so as to apply a first driving voltage to a heat generation element to discharge ink from an orifice and then apply a second driving voltage to the heat generation element so as not to cause bubbling or discharging of ink. In this case, the control unit performs control to apply the second driving voltage before detection of a feature point on the waveform of a signal representing temperatures in a temperature drop process detected by the temperature detection element after application of the first driving voltage and along with the application of the first driving voltage based on a temperature detected by a temperature detection element.

Abstract: An ink jet head includes a plurality of nozzles and a piezoelectric member provided with driving channels for storing ink. Each of the driving channels communicates a respective one of the nozzles. Dummy channels are alternately arranged with the driving channels. First side walls between the driving and dummy channels include a first driving channel side surface and a first dummy side surface. Second side walls between the driving channels and the dummy channels include a second driving channel side surface and a second dummy channel side surface. When a voltage is applied to electrodes on the first dummy channel side surfaces, the corresponding first side wall is deformed. When a voltage is applied to electrodes on the second dummy channel side surfaces, the second side wall is deformed.

Abstract: Each of M head units of a print head includes a driving signal generator and a plurality of piezoelectric elements. A common control signal is supplied from a control signal supply portion of a control unit to the respective driving signal generators of the M head units. The driving signal generator of each head unit generates a driving signal from the control signal according to characteristics (for example, relationship of a deformation amount with respect to an applied voltage) of each latter stage piezoelectric element and supplies the driving signal to each piezoelectric element.

Abstract: In accordance with one embodiment, an ink jet head comprises a driving signal generator configured to apply rectangular waveform electric field pulse to a partition wall forming a pressure chamber for ejecting ink; wherein the driving signal generator applies, to a second partition wall adjacent to a first partition wall forming the pressure chamber for ejecting ink and a third partition wall adjacent to the second partition wall, electric field pulse including at least one rectangular waveform which is a rectangular waveform opposite to the electric field pulse applied to the adjacent first partition wall and has a pulse width determined based on the electric field pulse at the timing corresponding to the electric field pulse applied to the first partition wall, in a case of ejecting ink from any of the plurality of pressure chambers.

Abstract: A printing apparatus that is an inkjet printing apparatus includes a print head that includes a plurality of nozzles that eject liquid droplets, and prints output data onto a recording medium in a plurality of scans, a storage unit including number of storage areas, the number being determined based on a scheme of the scans, an intermediate data generating unit that generates intermediate data corresponding to an image to be output in each of the scans of the print head from input image data, an intermediate data storing processing unit that stores the intermediate data in different storage areas of the storage unit corresponding to the respective scans of the print head, and an output data converting unit that converts the intermediate data stored in the storage unit into the output data, and sends the output data to the print head.

Abstract: A method for operating an inkjet printer includes forming a printed mark with a plurality of inkjets in a printhead, generating scanned image data of the printed mark, and modifying an image data correction parameter and firing signal waveform parameter for one of the inkjets to correct a process direction registration error between the locations of ink drops from the one inkjet and the location of the printed mark. The image data correction parameter modifies the location of ink drops from the one inkjet by an integer number of pixels and the firing signal waveform parameter modifies the location of ink drops from the one inkjet by a fractional pixel to enable registration of the inkjet.

Abstract: To provide an ink jet recording apparatus in which the residual vibration of any ink can be prevented to avoid the spread of the ink at an opening portion and to perform the continuous discharge of the ink stably. An ink-jet recording apparatus includes a recording head including a pressure chamber and a nozzle, the pressure chamber containing ink, the nozzle communicating with the pressure chamber and having an opening portion formed therein to discharge the ink, a piezoelectric element forming part of the pressure chamber, and a driving signal producing section producing a driving signal to be input to the piezoelectric element to change the volume of the pressure chamber.

Abstract: A liquid discharge apparatus is provided, comprising a channel structure; a piezoelectric actuator which has a plurality of individual electrodes, a common electrode, and a piezoelectric layer sandwiched between the individual electrodes and the common electrode; and a driving device which drives the piezoelectric actuator. The driving device outputs an individual driving signal which causes a change of an electric potential of the individual electrode, to the individual electrode corresponding to the nozzle for discharging the liquid. Further, the driving device outputs a common driving signal which causes a change of an electric potential of the common electrode in synchronization with the change of the electric potential of the individual electrode into which the individual driving signal is inputted, to the common electrode.

Abstract: A recording apparatus includes a recording head, a roller configured to convey a recording medium, an acquisition unit configured to acquire information about a conveyance amount for conveying the recording medium per a predetermined rotation amount of the roller, a recording timing generation unit configured to generate a plurality of timing signals for performing recording for one raster line according to a rotation of the roller during one rotation thereof, and a drive signal generation unit configured to generate a drive reference signal for performing the recording for the one raster line on the recording medium at a predetermined interval based on the conveyance amount information and the timing signal.

Abstract: A recording apparatus includes a recording unit configured to record a first dot and a second dot having a diameter smaller than that of the first dot on a recording medium, and a scanning unit configured to move the recording unit in a scanning direction. A recording resolution of the second dot in the scanning direction is lower than a recording resolution of the first dot in the scanning direction.

Abstract: An inkjet head includes a plurality of pressure chambers, each in communication with an ink supply, a plurality of piezoelectric members configured to deform to vary the volume of the pressure chambers, and drive unit that applies a driving signal to each of the piezoelectric members. The driving signal includes, in order, a first negative voltage over a first period having a predetermined length, a first positive voltage followed by a zero voltage over a second period having the same length, a second positive voltage over a third period having the same length, the zero voltage followed by a second negative voltage over a fourth period having the same length, and the zero voltage over a fifth period having the same length. The predetermined length is a half of an inherent vibration cycle of ink that is within the pressure chamber.

Abstract: An ink jet recording apparatus includes a liquid-ejecting head including a pressure-generating chamber filled with a photocurable ink composition containing a polymerizable functional group-containing compound and water, a nozzle communicating with the pressure-generating chamber and ejecting a droplet of the photocurable ink composition, and a pressure-generating member causing a pressure change in the pressure-generating chamber; and an ejection pulse-generating unit generating an ejection pulse for driving the pressure-generating member.

Abstract: An ink jet recording device includes an ink jet recording head including a pressure chamber communicating with an ink ejection orifice, and a piezoelectric actuator pressurizing ink in the pressure chamber. A drive signal generating unit generates a drive waveform having multiple drive pulses. A pulse supplying unit selects one or more of the drive pulses from the drive waveform depending on a size of an ink drop to be ejected and supplies the selected drive pulses to the piezoelectric actuator. The drive pulses in the drive waveform include ejection pulses to eject the ink drop from the orifice and a non-ejection pulse to suppress residual oscillations of the ink. The pulse supplying unit is configured to select one or more of the ejection pulses and the non-ejection pulse when an ink drop having a maximum size is to be ejected.

Abstract: A minute vibration driving signal is configured to include a first signal section which generates a plurality of minute vibration driving pulses, and a second signal section which maintains potential to a constant level without generating the minute vibration driving pulse, and can select a first mode in which duration of the second signal section is set to T2 which is longer than duration T1 of the first signal section, and a second mode in which duration of the second signal section is set to T4 which is longer than T2.

Abstract: According to one embodiment, the inkjet head of an application example includes a pressure chamber for charging the ink, an actuator for changing the volume of the pressure chamber, a nozzle for discharging the ink inside the pressure chamber when the volume of the pressure chamber is changed, and a controller that, in the formation of one pixel by discharging ink drops from the nozzle, when the elapsed interval from discharging ink drops last time by the nozzle is less than the specified interval, outputs the discharging waveform corresponding to the ink drop number determined for the formation of the pixel, and when the elapsed interval is more than the specified interval, increases the number of ink drop discharge cycles above the number determined for the formation of the pixel.

Abstract: A method, apparatus, and system are described herein for driving a droplet ejection device with multi-pulse waveforms. In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a multi-pulse waveform with a drop-firing portion having at least one drive pulse and a non-drop-firing portion to an actuator of the droplet ejection device. The non-drop-firing portion includes a jet straightening edge having a droplet straightening function and at least one cancellation edge having an energy canceling function. The at least drive pulse causes the droplet ejection device to eject a droplet of a fluid.

Abstract: An inkjet printing apparatus includes a printhead including a temperature sensor and an element array formed by arraying a plurality of heat generation elements each of which generates a thermal energy required to discharge an ink in response to application of a driving pulse, a specifying unit configured to specify a portion used in printing of the element array, and a selection unit configured to select a driving pulse to be applied to the respective heat generation elements based on the portion specified by the specifying unit and a temperature of the printhead measured by the temperature sensor.

Abstract: A liquid discharge apparatus includes first and second discharge sections, first and second connection paths and a voltage generation section. Each of the first and second discharge sections has a nozzle configured and arranged to discharge a liquid, a pressure chamber in communication with the nozzle, and a piezoelectric element. The first connection path selection section is arranged so as to correspond to the first discharge section and configured to selectively supply a plurality of voltages to the first discharge section. The second connection path selection section is arranged so as to correspond to the second discharge section and configured to selectively supply a plurality of voltages to the second discharge section. The voltage generation section is configured to generate and supply the voltages shared by the first connection path selection section and the second connection path selection section.

Abstract: An image forming apparatus includes: a recording head including multiple nozzles and multiple piezoelectric elements that generate pressure for causing droplets to be ejected from the nozzles; a driving-waveform generating unit that generates a driving waveform to be applied to the piezoelectric elements; first switching devices each disposed between the driving-waveform generating unit and respective one of the piezoelectric elements; second switching devices each disposed between a predetermined voltage and respective one of the piezoelectric elements; and a slight-vibration control unit. The slight-vibration control unit causes slight vibrations to be applied to a non-ejection nozzle by placing the second switch device for the non-ejection nozzle in a conduction state, and, when a predetermined period of time has elapsed after shift to the conduction state, placing the second switch device in a non-conduction state and the first switch device for the non-ejection nozzle in a conduction state.

Abstract: An image forming apparatus includes a liquid ejection head including a pressure generation unit configured to generate a pressure for pressurizing a liquid in an individual liquid chamber communicating nozzles; and a head drive control unit configured to generate a drive waveform including pulses in time series, select one or more pulses from the drive waveform according to a droplet size, and provide the selected drive pulses to the pressure generation unit. The drive waveform includes a first pulse not including a waveform component that suppresses ejection bending, and allowing a droplet to be ejected, and a second pulse including the waveform component that suppresses ejection bending, and allowing a droplet to be ejected. An amount of the droplet ejected in the second pulse is larger than in the first pulse, and a speed of the droplet ejected in the second pulse is higher than that in the first pulse.

Abstract: Disclosed is a driving device of a liquid-jet head having a piezoelectric device arranged for each of nozzles and having mutually facing electrodes. The driving device includes switching devices connected in parallel to each other, one of the electrodes being connected to first ends of the switching devices for selectively ON/OFF controlling the switching devices while the other electrode is connected to a reference potential, a driving signal source to generate a driving signal connected to second ends of the switching devices, and a control unit to switch the driving signal to ON or OFF control the switching devices. At least one of the switching devices has electrically conducting properties for not ejecting a liquid drop from the nozzle with a driving signal being applied to the switching device in an ON-controlled status, and the switching devices are all ON-controlled for causing the nozzles to eject liquid drops.

Abstract: An embodiment of this invention relates to an element substrate that implements size reduction of the element substrate and simplification of the arrangement as well as a highly-reliable print operation, a printhead using the same, and a printing apparatus including the printhead. In the element substrate according to this embodiment, the slope of a ramp wave is changed to generate a plurality of pulses using one reference voltage. The slope of the ramp wave can be changed by changing the mirror ratio or the capacitance of a comparator as well as by changing the resistance of a DAC.

Abstract: A device for driving a recording head comprises select data input elements, a waveform signal selector, and a drive signal supplier. To the select data input elements, select data sets corresponding to recording elements included in the recording head are inputted in a serial manner. Each one of the select data sets indicates which one among waveform signals is to be employed for a corresponding recording element in a single printing cycle. The waveform signal selector selects, for each of the recording elements, one among the waveform signals on the basis of a corresponding one among the select data sets inputted to the select data input. The drive signal supplier supplies, based on the selected waveform signal, a drive signal to each of the recording elements. The number of the select data input elements is greater than the number of bits included in each of the select data sets.

Abstract: Described herein is a method, apparatus, and system for driving a droplet ejection device with multi-pulse waveforms. In one embodiment, a method for driving a droplet ejection device having an actuator includes applying a first subset of a multi-pulse waveform to the actuator to cause the droplet ejection device to eject a first droplet of a fluid in response to the first subset. The method includes applying a second subset of the multi-pulse waveform to the actuator to cause the droplet ejection device to eject a second droplet of the fluid in response to the second subset. The first subset includes a drive pulse that is positioned in time near a beginning of a clock cycle of the first subset. The first droplet has a smaller volume than the second droplet.

Abstract: In an inkjet printer, for forming a large dot on a recording paper in the course of image recording, a second ejection pulse (721) and a first ejection pulse (713) are selected from a basic waveform (70), as a driving signal. For forming a medium dot, a first minute pulse (711) and the first ejection pulse (713) are selected. For forming a small dot, a third ejection pulse (722) is selected. At the time of non-ejection, a second minute pulse (712) is selected. As a result, by adjusting the waveform of the first minute pulse (711), it is possible to form high-quality dots of respective sizes while shortening a driving cycle with the use of the first ejection pulse (713) for forming a large dot and a medium dot.

Abstract: An encoder sensor is mounted on a printhead and optically reads an encoder film. And a number of pulses of a pulse signal proportional to a moving amount of a printhead is counted and stored as a count value in a memory within multiple ICs. The count value stored in the memories is reset while the pulse signal outputted from the encoder sensor is blocked by a gate or while a region other than near a boundary between a penetration region and a non-penetration region of the encoder film is being read.

Abstract: An image forming apparatus includes: a liquid droplet discharge head; a pressure generator; and a driving waveform generator configured to generate a driving waveform including a plurality of pulse units for driving the pressure generator for discharging a liquid droplet. The pulse unit includes one or more first pulses, and one or more second pulses arranged after the first pulses for discharging a liquid droplet. The second pulse has a pulse width that is set in advance to generate a resonance with the liquid droplet discharge head. The first pulse has a pulse width different from the pulse width of the second pulse.

Abstract: A method of ejecting a drop of fluid includes providing a fluid ejector. The fluid ejector includes a substrate, a MEMS transducing member, a compliant membrane, walls, and a nozzle. The substrate includes a cavity and a fluidic feed. A first portion of the MEMS transducing member is anchored to the substrate. A second portion of the MEMS transducing member extends over at least a portion of the cavity and is free to move relative to the cavity. The compliant membrane is positioned in contact with the MEMS transducing member. A first portion of the compliant membrane covers the MEMS transducing member, A second portion of the compliant membrane being anchored to the substrate. Walls define a chamber that is fluidically connected to the fluidic feed. At least the second portion of the MEMS transducing member is enclosed within the chamber. A quantity of fluid is supplied to the chamber through the fluidic feed.

Abstract: A drive signal generating unit that generates a drive signal applying, in one pixel period, at least one drive waveform for causing ink droplets to be discharged can generate two types of drive waveforms, a large droplet waveform and a small droplet waveform. The large droplet waveform includes an expansion pulse expanding the volumes of pressure chambers and a contraction pulse making the volumes of the pressure chambers contract. The expansion pulse width of the large droplet waveform is 2.8 AL or longer but 3.4 AL or shorter. The small droplet waveform includes an expansion pulse, a pause period, and a contraction pulse, and the expansion pulse width of the small droplet waveform is 0.8 AL or longer but 1.2 AL or shorter, where AL represents a half of an acoustic resonance period of a pressure wave in the pressure chamber.

Abstract: A liquid ejecting apparatus includes a reference drive signal generation section that generates a reference drive signal, a signal modulation section that modulates the reference drive signal to generate a modulation reference drive signal, a signal amplification section that amplifies the modulation reference drive signal using switching elements to generate a modulation drive signal, a signal conversion section that converts the modulation drive signal to a drive signal, a piezoelectric element that deforms in response to the drive signal, a pressure chamber that expands or contracts due to the deformation of the piezoelectric element, and a nozzle opening portion that communicates with the pressure chamber. A period of alternating current components contained in the modulation drive signal are shorter than a duration of a maximum voltage or a minimum voltage, and is longer than a total time of turn-on delay times and turn-off delay times of the switching elements.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: A time from a start end of a contraction portion of a first middle dot drive pulse of a first drive signal to a start end of the contraction portion of a second middle dot drive pulse of a second drive signal is set to Tc/2 or more and Tc or less in the same unit period. In addition, a time from a start end of a preliminary portion of a first small dot drive pulse to a start end of a preliminary portion of a second small dot drive pulse is set to Tc or more. Thus, while a piezoelectric vibrator corresponding to the other side of adjacent nozzles is driven by the second drive signal, a piezoelectric vibrator corresponding to one side of adjacent nozzles is driven by the first drive signal.

Abstract: An inkjet printhead includes an array of resistive heaters; an array of nozzles associated with the array of resistive heaters; a heater voltage input for providing a heater voltage; a fire control pulse input for providing a fire control pulse having a first pulsewidth for controlling a length of time that current from the heater voltage input is allowed to pass through at least one of the resistive heaters; and a protective circuit configured to receive the fire control pulse from the fire control pulse input, and to override the fire control pulse if the first pulsewidth is greater than or equal to a predetermined length of time.

Abstract: A method of operating an inkjet printing system includes turning a heater voltage power source providing drop generation power to an inkjet printhead on or off under direction of a controller; providing a fire control pulse for setting a duration of passage of current from the heater voltage power source through one or more resistive heaters for generation of one or more drops of ink under direction of the controller; inputting the fire control pulse into a protective circuit; and overriding the fire control pulse in the setting of the duration of passage of current from the power source through the one or more resistive heaters if the pulsewidth of the fire control pulse is greater than or equal to a predetermined length of time.

Abstract: A power supply section includes a switching regulator. A plurality of linear regulators is provided for respective ones of a plurality of driving sections. The linear regulators step down a source voltage to respective driving voltages of the driving sections and supply the respective driving sections with the driving voltages. A head-temperature sensor measures temperature of a liquid ejecting head. A controller determines the source voltage and the driving voltages based on the temperature, and controls the power supply section, the linear regulators, and the driving sections to stop at least one of outputting of the source voltage by the power supply section, supplying of the driving voltages by the linear regulators, and driving of the driving sections, when a voltage difference is larger than or equal to an acceptable value. The voltage difference is a difference between the source voltage and a minimum voltage of the driving voltages.

Abstract: A liquid ejecting apparatus includes a drive signal generation section which generates a drive signal and a liquid ejecting head. The drive signal is a periodic signal. One period of the drive signal has two durations of (i) a droplet ejection duration with a waveform part used to eject the droplet from the nozzle and (ii) a droplet non-ejection duration without the waveform part used to eject the droplet from the nozzle, and the droplet non-ejection duration is equal to or longer than the droplet ejection duration.