摘要:
Operation of a digital power amplifier for power amplification of a modulated signal is stopped in a period in which a voltage value of a drive signal applied to a capacitive load is constant, to thereby suppress power loss. The power amplification is stopped either when half a period of time when the modulated signal in a first voltage state maintains the first voltage state elapses or when half a period of time when the modulated signal in a second voltage state which is lower in voltage than the first voltage state maintains the second voltage state elapses. Accordingly, when electric current does not flow in a inductor of a low pass filter, it is possible to stop the power amplification. Thus, it is possible to prevent generation of voltage fluctuation in the drive signal due to an electromotive force caused by a self-induction phenomenon of the inductor.
摘要:
A liquid ejection device, includes: a drive waveform signal output circuit which outputs a drive waveform signal to serve as a reference for the drive signal; a modulator which pulse-modulates the drive waveform signal and thus generates a first modulated signal and a second modulated signal having a different phase from the first modulated signal within a range from greater than 90 degrees to smaller than 270 degrees; a first digital power amplifier; a second digital power amplifier a first low pass filter which performs low pass filtering of the first amplified digital signal and thus generates a first demodulated signal; and a second low pass filter which performs low pass filtering of the second amplified digital signal and thus generates a second demodulated signal; wherein the first demodulated signal and the second demodulated signal are combined and applied as the drive signal to the capacitive load.
摘要:
A liquid ejection device includes: a drive waveform generator generating a drive waveform signal; a modulator performing pulse modulation on a signal from the drive waveform generator to provide a modulated signal; a digital power amplifier performing power amplification on the modulated signal to provide an amplified digital signal; a Lowpass Filter smoothing the amplified digital signal to provide a drive signal of an actuator; a compensator advancing the phase of the drive signal to provide a negative feedback signal; and a subtractor providing a differential signal between the drive waveform signal and the negative feedback signal as an input signal to the modulator.
摘要:
A head drive apparatus of an inkjet printer includes nozzles and corresponding actuators that eject liquid drops. A drive unit applies a drive signal to the actuators. The drive unit includes a drive waveform generator that generates a drive waveform signal as a reference of a signal to control drive of the actuators. A modulator pulse modulates a drive waveform signal generated by the drive waveform generator. A digital power amplifier amplifies power of a modulated signal subjected to the pulse modulation. A low pass filter smoothes an amplified digital signal subjected to the power amplification by the digital power amplifier and supplying the signal as a drive signal to the actuators. An inverse filter provided in a subsequent stage of the drive waveform generator corrects at least the frequency characteristics of the filter to predetermined frequency characteristics, independently of the number of the actuators to drive.
摘要:
A fluid ejection device that ejects fluid from an ejection port includes: a drive element that ejects fluid in accordance with a difference between voltages applied to a first terminal and a second terminal; a drive voltage waveform storing unit that stores a drive voltage waveform applied to the drive element; a plurality of power supplies each having a different voltage; and a drive voltage waveform applying unit that applies the drive voltage waveform to the drive element by switching among the plurality of power supplies connected to the first and second terminals of the drive element.
摘要:
A power amplifier includes: a modulator pulse-modulating a drive waveform signal serving as a reference of a drive signal applied to an actuator and outputting a plurality of modulated signals; a digital power amplifier having a plurality of digital power amplifier stages each including a pair of push-pull switching elements, amplifying the power of the plurality of modulated signals, and outputting multi-value amplified digital signals; and a low pass filter smoothing the amplified digital signals and outputting the drive signal, wherein the modulator includes a control section switching one of a state where the same modulated signal is connected to two or more of the digital power amplifier stages and a state where different modulated signals are connected to different digital power amplifier stages to the other.
摘要:
A fluid feed pump is configured, such that a fluid is fed from an outlet channel of the fluid feed pump through an outlet buffer chamber to a fluid channel. The outlet buffer chamber is designed to have a higher compliance than a compliance of a pump chamber. The driving period of the fluid feed pump is set to a shorter period than a time constant defined by the compliance of the pump chamber and a flow resistance between an inlet of the outlet channel and an outlet of the fluid channel. This enables the fluid to be fed with high efficiency by taking advantage of the pressure oscillation occurring between the pump chamber and the outlet buffer chamber.
摘要:
A capacitive load driving circuit that drives an electrical load having a capacitive component, includes: a first power supply generating a first voltage; a second power supply generating a second voltage different from the first voltage; a plurality of charge storage elements charged by the first power supply; a first connection unit that connects the plurality of charge storage elements to the electrical load by switching connections among the charge storage elements; and a second connection unit that connects the second power supply to the electrical load.
摘要:
A liquid jet apparatus according to the present invention includes a drive waveform generator adapted to generate a drive waveform signal, a modulator adapted to execute pulse modulation on the drive waveform signal, a digital power amplifier adapted to power-amplify the modulated signal, on which the pulse modulation is executed by the modulator, with a pair of switching elements push-pull coupled with each other, a low pass filter adapted to smooth the amplified digital signal obtained by the power-amplification of the digital power amplifier, and a modulation period modification circuit adapted to modify a modulation period of the pulse modulation of the modulator based on data of the drive waveform signal.
摘要:
An image processing apparatus includes: an image data acquiring unit that acquires image data formed of plural pixel data having an M-ary (M≧3) gradation value; a grouping unit that divides the image data acquired into J (J≧2) image data areas and sections the J image data areas into K (2≦K≦J) groups; a pixel data selecting unit that selects, for each of the image data areas forming the respective groups, predetermined pixel data out of pixel data included in the image data area; an N-arization processing unit that applies the N-arization (M>N≧2) processing to the pixel data selected on the basis of a predetermined threshold value; and an error diffusing unit that diffuses a difference between a value of the selected pixel data and a value after the N-arization processing for the selected pixel data to pixel data not subjected to the N-arization processing, wherein the error diffusing unit diffuses the difference in directions different from one another in two or more groups of the K groups.