Minolta Camera Kabushiki Kaisha

Silver Seiko Ltd.

Sr Technos Ltd.,

Masayuki Mutoh

Toshihiro Hayashi

Shozo Kaieda

Kuniaki Kamimura

Shinji Kamiyama

Takanobu Ishidoh

An ink jet recording apparatus with ink drop registration control adjusts the timing of the ink drop or drops that form each pixel to compensate for time-of-flight differences that are a function of the number of ink drops that form a pixel and as a function of the ink drops that constitute one or more immediately preceding pixels. A pixel buffer stores successive pixel data in a first-in first-out (FIFO) manner so that the timing of the ink drop for a current pixel can be adjusted, in part, as a function of the number of ink drops of at least one next successive pixel.

Ink jet recording apparatus with ink drop registration control

The optimum excitation frequency for forming successive ink drops in an ink jet printer is determined by forming a sequence of ink drops at a plurality of different drop-formation frequencies and phases thereof and integrating a detected current representative of the value of the charge on the ink drops as a function of time for each the plural frequencies and phases thereof to create a corresponding plurality of waveforms. The frequency of the optimum waveform, which minimizes the undesired formation of satellite ink drops and undesired drop dispersion, is then selected for use during the next print mode. The optimum waveform is characterized by a single maxima and minima separated in phase by a value no greater than a predetermined maximum value.

Method and apparatus for determining optimum ink drop

An ink jet recording apparatus wherein ink drops can be controlled individually to assure high quality printing and adjustment in registration of ink nozzles in a drum circumferential direction can be performed at a sufficiently high resolution. The ink jet recording apparatus has a plurality of nozzles arranged such that drops of ink may impinge in an overlapping relationship at a location on a record medium supported on a rotary drum, and adjustment in registration of the nozzles in a drum circumferential direction is performed by a registration adjusting system by which such adjustment is performed using a registration adjusting clock signal having a frequency higher than a picture element recording signal. An optimum phase between disintegration of an ink jet and a recording pulse signal is determined in accordance with current values detected by a current detector connected to an electrically isolated conductive drop catcher.

Optimum phase determination based on the detected jet current

An ink jet recording apparatus wherein ink drops can be controlled individually to assure high quality printing and adjustment in registration of ink nozzles in a drum circumferential direction can be performed at a sufficiently high resolution. The ink jet recording apparatus includes a plurality of nozzles arranged such that drops of ink may impinge in an overlapping relationship at a location on a record medium supported on a rotary drum, and adjustment in registration of the nozzles in a drum circumferential direction is performed by a registration adjusting system by which such adjustment is performed using a registration adjusting clock signal having a frequency higher than a picture element recording signal. An optimum phase between disintegration of an ink jet and a recording pulse signal is determined in accordance with current values detected by a current detector connected to an electrically isolated conductive drop catcher.

Ink jet recording apparatus having drop-registration adjusting system

An ink jet recording apparatus of the continuous jet type wherein the position of an ink jet jetting axis or nozzle axis can be detected readily with a simplified construction. The ink jet recording apparatus comprises test signal generating means which generates a controlling signal which varies continuously. Switch means selectively couples one of recording signal generating means and the test signal generating means to a controlling electrode of charging means provided for charging an ink drop. An electrically isolated conductive drop catcher catches an ink drop which has passed by separating means for forming an ink jet, and current detecting means detects electric charge carried to the conductive drop catcher by charged ink drops as an electric current. Relative position detecting means measures a relative positional relationship between an ink jet flying axis and the separating means from a controlling voltage outputted from the test signal generating means and an output of the current detecting means.

Ink jet recording apparatus of the continuous jet type

A continuous ink jet recording apparatus which can record an image always with an appropriate density on any of various record media. A vibrating element driver drives a piezoelectric vibrating element in response to a disintegrating frequency signal from an oscillator to disintegrate a jet of ink from a nozzle. A multiplier multiplies picture element data of a line buffer by a density coefficient, and a pulse width modulator converts the picture element data from the multiplier into a charging controlling signal of the pulse width which increases in proportion to the number of ink drops per picture element. The charging controlling signal is applied via a high voltage switch to a controlling electrode, by which the in drops are charged in accordance with the charging controlling signal. A deflecting electrode deflects the charged ink drops. A frequency divider and a frequency converter frequency divides the disintegrating frequency signal by a gradation number and the density coefficient to obtain a picture element recording frequency signal, and a drum motor controlling circuit drives a drum motor to rotate a rotary drum at a speed in accordance with the picture element recording frequency signal.

An ink jet printer in which a plurality of ink jet generators are moved in unison with one another and relative to a record medium for recording. Each of the ink jet generators comprises a nozzle for continuously ejecting an ink, a charge electrode for applying a pulse voltage to the ink to selectively charge droplets of the ejected ink, a deflector electrode for producing a deflection electric field for deflecting a row of charged droplets and permitting a row of uncharged droplets to proceed straight, an oscillation controller, an oscillator for oscillating the nozzle to control ink droplet formation in response to clock pulses output by the oscillation controller, a pulsewidth modulator for controlling a pulsewidth of the pulse voltage to be applied to the charge electrode according to a dot size to be recorded, a delay circuit for delaying the pulse voltage from the pulsewidth modulator, and a phase synchronizing circuit for outputting the pulse voltage of the delay circuit to the charge electrode in phase with the clock pulses output by the oscillation controller. This construction is capable of adjusting dot position displacement among the nozzles over a wide range without injuring control of the ink to a row of ink droplets, thereby to record images with high resolution and high tone reproduction.

Tone reproducible ink jet printer

There is disclosed an ink jet printer of Hertz type. An ink jet is continuously forced out from a nozzle and broken into minute droplets. The droplets are selectively charged by applying pulse voltage. A row of charged droplets is removed and a row of uncharged droplets proceeds to the record medium and forms a dot thereon. The pulse width is controlled in order to allow a number of droplets included in one row of droplets, so that the diameter of dot is altered. The ink jet printer is able to produce high degree of tones by alteration of number of uncharged droplets in combination of the dot pattern moduration method or the dither method.

A liquid tank structure for reducing hydrostatic pressure at an outlet thereof. The structure has a liquid container having an outlet at its lower portion, and a capillary member within the liquid container for exerting a force on a liquid therein in a direction opposite to the hydrostatic pressure of the liquid at the outlet for reducing the hydrostatic pressure at the outlet.

Liquid tank

In order to take advantage of an ink jet generating unit for preparing hectographic printing masters, solid ink is proposed. The solid ink is prepared by dispersing dye stuff of more than 10 percent by weight in a hydrocarbon of the thermally dissoluble type. Various types of apparatuses each incorporating the ink jet generating unit are also provided.

Process for preparing hectographic printing masters

An ink jet recording apparatus which effects non-impact recording by the application of a jet of ink to a recording medium while the amount of ink to be jetted towards the recording medium is controlled to render it proportional to the recording velocity. For this purpose, the ink jet recording apparatus is provided with a feed-back loop system through which an electrical signal indicative of the pressure acting on the ink within an ink tank is fed back to a comparator to control operation of a compressed air source from which the pressure is applied to compensate for reduction in static pressure of the ink within the ink tank resulting from consumption of the ink. For maintaining the amount of the ink jetted proportional to the recording velocity, various arrangements are disclosed.

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Machida, Japan

Masayuki Mutoh