Abstract: An image reading apparatus includes an image reading unit and a computational unit. The image reading unit includes a reference reflecting member that acts as a color reference, an illuminating unit that illuminates a part of the reference reflecting member and a sheet being transported in proximity thereto, a line sensor that reads an image formed on the sheet and the part of the reference reflecting member in proximity to the sheet in the sheet width direction, and a spectroscope that measures the spectral distribution of each of multiple patches for correcting color tones formed on the sheet and arranged in the sheet transport direction. The computational unit generates color tone correction data by performing computations based on the spectral distribution of each patch measured by the spectroscope, and the read values of the reference reflecting member obtained by the line sensor.

Abstract: An image reading apparatus includes an image reading unit and a computational unit. The image reading unit includes a reference reflecting member that acts as a color reference, an illuminating unit that illuminates a part of the reference reflecting member and a sheet being transported in proximity thereto, a line sensor that reads an image formed on the sheet and the part of the reference reflecting member in proximity to the sheet in the sheet width direction, and a spectroscope that measures the spectral distribution of each of multiple patches for correcting color tones formed on the sheet and arranged in the sheet transport direction. The computational unit generates color tone correction data by performing computations based on the spectral distribution of each patch measured by the spectroscope, and the read values of the reference reflecting member obtained by the line sensor.

Abstract: A capacitive load driving circuit including: a filter including an inductor to which an analog driving signal is input, and a capacitor with a fixed capacitance where one electrode is connected the inductor and other electrode grounded; a plurality of capacitive loads connected in parallel to the capacitor, and driven in accordance with the analog driving signal; a conversion section converting a load voltage to a digital signal; a signal processing section generating a predetermined signal for driving the capacitive load, deriving a signal that represents a magnitude of an electric current flowing to the capacitive load from the digital signal and a digital driving signal, subtracting the signal from the predetermined signal, and outputting the subtracted signal as the digital driving signal; and a switching section generating the analog driving signal by performing switching based on the digital driving signal, and outputting the analog driving signal.

Abstract: There is provided a capacitive load driving circuit which applies a driving signal to a capacitive load. The driving circuit includes: an operational amplifier outputting a difference signal between signals from an inverting input terminal and a non-inverting input terminal, and setting a loop gain; a pulse width modulator pulse-width-modulating the difference signal outputted by the operational amplifier, and outputting resultant digital signal; a digital voltage amplifier amplifying a voltage of the digital signal; a first filter smoothing a digital signal from the digital voltage amplifier, and supplying a smoothed signal to the capacitive load as the driving signal; an impedance converting circuit converting an impedance of an output signal of the first filter; and a first feedback circuit feeding-back the driving signal, which is outputted from the first filter, to the inverting input terminal of the operational amplifier via the impedance converting circuit.

Abstract: The present invention provides an inspection device for a piezoelectric head. The piezoelectric head includes: a pressure chamber filled with liquid, a liquid supply channel that supplies the liquid to the pressure chamber, a nozzle at which droplets are jetted from the pressure chamber, and a piezoelectric element that applies pressure to the pressure chamber. The inspection device includes: a detection component that, when the piezoelectric element is driven on the basis of a predetermined detection signal, outputs a signal corresponding to behavior of an acoustic vibration system of the piezoelectric head; and a judgment component that, on the basis of the detection signal and the signal outputted by the detection component, judges for a cause of defective ejections at the piezoelectric head.

Abstract: There is provided a capacitive load driving circuit which applies a driving signal to a capacitive load. The driving circuit includes: an operational amplifier outputting a difference signal between signals from an inverting input terminal and a non-inverting input terminal, and setting a loop gain; a pulse width modulator pulse-width-modulating the difference signal outputted by the operational amplifier, and outputting resultant digital signal; a digital voltage amplifier amplifying a voltage of the digital signal; a first filter smoothing a digital signal from the digital voltage amplifier, and supplying a smoothed signal to the capacitive load as the driving signal; an impedance converting circuit converting an impedance of an output signal of the first filter; and a first feedback circuit feeding-back the driving signal, which is outputted from the first filter, to the inverting input terminal of the operational amplifier via the impedance converting circuit.

Abstract: There is provided a capacitive load driving circuit which applies a driving signal to a capacitive load. The driving circuit includes: an operational amplifier outputting a difference signal between signals from an inverting input terminal and a non-inverting input terminal, and setting a loop gain; a pulse width modulator pulse-width-modulating the difference signal outputted by the operational amplifier, and outputting resultant digital signal; a digital voltage amplifier amplifying a voltage of the digital signal; a first filter smoothing a digital signal from the digital voltage amplifier, and supplying a smoothed signal to the capacitive load as the driving signal; an impedance converting circuit converting an impedance of an output signal of the first filter; and a first feedback circuit feeding-back the driving signal, which is outputted from the first filter, to the inverting input terminal of the operational amplifier via the impedance converting circuit.

Abstract: An ink non-ejection detecting circuit device for an inkjet recording apparatus is disclosed which comprises a bridge circuit including a piezoelectric head having a piezoelectric element, a first resistor connected in series to the piezoelectric head, a capacitor provided outside the piezoelectric head, and a second resistor connected in series to the capacitor. A differential voltage that appears between the piezoelectric head and the first resistor and between the capacitor and the second resistor is amplified, so that the acoustic-system admittance of the piezoelectric head can be detected with a high SN ratio.

Abstract: A capacitive load driving circuit includes: a phase lead compensator, advancing a phase of an output signal of a filter; a series compensator, determining an error between a driving signal and an output signal of the phase lead compensator; a stabilization compensator, performing a derivative action on an output signal of the filter; a voltage comparison unit, comparing a differential voltage between a signal output from the series compensator and a signal output from the stabilization compensator, with a voltage of a predetermined triangular waveform, and outputting a pulse width modulation signal; a voltage amplification unit, amplifying the voltage of the pulse width modulation signal output, and supplying the amplified pulse width modulation signal to the input terminal of the filter; and plural capacitive loads each connected in parallel to the capacitor. A droplet ejection apparatus includes the capacitive load driving circuit.

Abstract: A capacitive load driving circuit including: a filter including an inductor to which an analog driving signal is input, and a capacitor with a fixed capacitance where one electrode is connected the inductor and other electrode grounded; a plurality of capacitive loads connected in parallel to the capacitor, and driven in accordance with the analog driving signal; a conversion section converting a load voltage to a digital signal; a signal processing section generating a predetermined signal for driving the capacitive load, deriving a signal that represents a magnitude of an electric current flowing to the capacitive load from the digital signal and a digital driving signal, subtracting the signal from the predetermined signal, and outputting the subtracted signal as the digital driving signal; and a switching section generating the analog driving signal by performing switching based on the digital driving signal, and outputting the analog driving signal.

Abstract: The present invention provides an inspection device for a piezoelectric head. The piezoelectric head includes: a pressure chamber filled with liquid, a liquid supply channel that supplies the liquid to the pressure chamber, a nozzle at which droplets are jetted from the pressure chamber, and a piezoelectric element that applies pressure to the pressure chamber. The inspection device includes: a detection component that, when the piezoelectric element is driven on the basis of a predetermined detection signal, outputs a signal corresponding to behavior of an acoustic vibration system of the piezoelectric head; and a judgment component that, on the basis of the detection signal and the signal outputted by the detection component, judges for a cause of defective ejections at the piezoelectric head.

Abstract: The present invention provides an inspection device for a piezoelectric head. The piezoelectric head includes: a pressure chamber filled with liquid, a liquid supply channel that supplies the liquid to the pressure chamber, a nozzle at which droplets are jetted from the pressure chamber, and a piezoelectric element that applies pressure to the pressure chamber. The inspection device includes: a detection component that, when the piezoelectric element is driven on the basis of a predetermined detection signal, outputs a signal corresponding to behavior of an acoustic vibration system of the piezoelectric head; and a judgment component that, on the basis of the detection signal and the signal outputted by the detection component, judges for a cause of defective ejections at the piezoelectric head.

Abstract: A driving circuit of a droplet ejection head which, by supplying analog driving signals to driving elements, ejects droplets from nozzles which are provided in correspondence with the driving elements. The driving circuit includes a driving signal generation unit, a pulse modulation unit, a switching signal generation unit, an amplification unit and a frequency-setting unit. The driving signal generation unit selectively outputs a first and a second analog driving signal. The pulse modulation unit pulse-modulates the analog driving signal and outputs a digital signal. The switching signal generation unit generates a switching signal. The amplification unit amplifies the digital signal by switching in accordance with the switching signal, and supplies the amplified digital signal to the driving elements. The frequency-setting unit sets a switching frequency of the switching signal in accordance with a frequency selection signal, which corresponds to the analog driving signal.

Abstract: A capacitive load driving circuit includes: a phase lead compensator, advancing a phase of an output signal of a filter; a series compensator, determining an error between a driving signal and an output signal of the phase lead compensator; a stabilization compensator, performing a derivative action on an output signal of the filter; a voltage comparison unit, comparing a differential voltage between a signal output from the series compensator and a signal output from the stabilization compensator, with a voltage of a predetermined triangular waveform, and outputting a pulse width modulation signal; a voltage amplification unit, amplifying the voltage of the pulse width modulation signal output, and supplying the amplified pulse width modulation signal to the input terminal of the filter; and plural capacitive loads each connected in parallel to the capacitor. A droplet ejection apparatus includes the capacitive load driving circuit.

Abstract: An ink non-ejection detecting circuit device for an inkjet recording apparatus is disclosed which comprises a bridge circuit including a piezoelectric head having a piezoelectric element, a first resistor connected in series to the piezoelectric head, a capacitor provided outside the piezoelectric head, and a second resistor connected in series to the capacitor. A differential voltage that appears between the piezoelectric head and the first resistor and between the capacitor and the second resistor is amplified, so that the acoustic-system admittance of the piezoelectric head can be detected with a high SN ratio.

Abstract: An ink non-ejection detecting circuit device for an inkjet recording apparatus is disclosed which comprises a bridge circuit including a piezoelectric head having a piezoelectric element, a first resistor connected in series to the piezoelectric head, a capacitor provided outside the piezoelectric head, and a second resistor connected in series to the capacitor. A differential voltage that appears between the piezoelectric head and the first resistor and between the capacitor and the second resistor is amplified, so that the acoustic-system admittance of the piezoelectric head can be detected with a high SN ratio.

Abstract: The present invention provides an inspection device for a piezoelectric head. The piezoelectric head includes: a pressure chamber filled with liquid, a liquid supply channel that supplies the liquid to the pressure chamber, a nozzle at which droplets are jetted from the pressure chamber, and a piezoelectric element that applies pressure to the pressure chamber. The inspection device includes: a detection component that, when the piezoelectric element is driven on the basis of a predetermined detection signal, outputs a signal corresponding to behavior of an acoustic vibration system of the piezoelectric head; and a judgment component that, on the basis of the detection signal and the signal outputted by the detection component, judges for a cause of defective ejections at the piezoelectric head.

Abstract: A driving circuit of a droplet ejection head which, by supplying analog driving signals to driving elements, ejects droplets from nozzles which are provided in correspondence with the driving elements. The driving circuit includes a driving signal generation unit, a pulse modulation unit, a switching signal generation unit, an amplification unit and a frequency-setting unit. The driving signal generation unit selectively outputs a first and a second analog driving signal. The pulse modulation unit pulse-modulates the analog driving signal and outputs a digital signal. The switching signal generation unit generates a switching signal. The amplification unit amplifies the digital signal by switching in accordance with the switching signal, and supplies the amplified digital signal to the driving elements. The frequency-setting unit sets a switching frequency of the switching signal in accordance with a frequency selection signal, which corresponds to the analog driving signal.

Abstract: A capacitive load driving circuit which includes an operational amplifier, a pulse width modulator, a digital power amplifier, a first filter, a first feedback circuit and a second feedback circuit. The operational amplifier outputs a differential signal between a signal fed back to the inverting input terminal and an input signal inputted to the non-inverting input terminal. The pulse width modulator pulse width-modulates output from the operational amplifier and outputs a digital signal. The digital power amplifier amplifies power of the digital signal. The first filter smooths output of the digital power amplifier and inputs the smoothed signal to the capacitive load as the driving signal. The first feedback circuit feeds back the driving signal outputted from the first filter to the inverting input terminal of the operational amplifier.

Abstract: There is provided a capacitive load driving circuit which applies a driving signal to a capacitive load. The driving circuit includes: an operational amplifier outputting a difference signal between signals from an inverting input terminal and a non-inverting input terminal, and setting a loop gain; a pulse width modulator pulse-width-modulating the difference signal outputted by the operational amplifier, and outputting resultant digital signal; a digital voltage amplifier amplifying a voltage of the digital signal; a first filter smoothing a digital signal from the digital voltage amplifier, and supplying a smoothed signal to the capacitive load as the driving signal; an impedance converting circuit converting an impedance of an output signal of the first filter; and a first feedback circuit feeding-back the driving signal, which is outputted from the first filter, to the inverting input terminal of the operational amplifier via the impedance converting circuit.