Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Masatoshi Sakata

Shigenori Suematsu

Yutaka Shoji

Kazuo Shimizu

Atsushi Kakuta

Takahiro Yamada

Yasumasa Matsuda

Takuji Torii

Yoshitaka Akiyama

Nobuhiro Noto

Yasuo Takano

Takashi Sekino

Keiji Kunimi

Makoto Yoshino

To eliminate influence of cross-talk in an on-demand multi-nozzle ink jet head, drive pulses to be applied to piezoelectric elements for driving nozzles aligned in a row are individually adjusted so that the nozzles eject ink droplets at the same speed when the nozzles are driven simultaneously. To the piezoelectric elements which are deactuated during printing, a dummy drive pulse having a voltage level in a range from 50 to 75% of a minimum voltage for ejecting an ink droplet is applied, whereby the ejection speed achieved when individual nozzles are driven approaches the ejection speed achieved when all nozzles are driven simultaneously. As such, the print quality is improved.

Drive voltage adjusting method for an on-demand multi-nozzle ink jet head

A solid-ink printing original plate which comprises a substrate and an image comprising ink dots formed on the substrate, and which is produced by a process comprising the steps of: melting a solid ink that is a solid at a room temperature; and jetting the melt of the solid ink onto a substrate to form ink dots, wherein the solid ink has a penetration index of not more than 5 at a room temperature. Also disclosed is a process for producing the solid-ink printing original plate.

Solid-ink printing original plate and a process for producing the same

A piezoelectric type ink recording device has piezoelectric elements for ejecting ink droplets. Variation can exist in characteristics of the piezoelectric elements that results in variation in speed at which the piezoelectric elements eject ink droplets. In order to suppress this variation in ejection speed, the ink recording device has a driver shared by all of the piezoelectric elements and a separate discharge control circuit for each piezoelectric element. The driver shared and the separate discharge control circuits output pulses to the piezoelectric elements in synchronization. Each piezoelectric element starts discharging its charge in synchronization with the falling edge of a drive pulse from the driver. As a result, the piezoelectric elements deform during the falling edge of the drive pulse to increase volume of corresponding ink chambers, thereby drawing ink into the ink chambers. However, each piezoelectric element continues discharging for a time determined by the width of the pulse from the corresponding discharge control circuit. In this way, the amount of charge discharged from each piezoelectric element can be individually regulated by changing the pulse waveform applied to each piezoelectric element by the corresponding discharge control circuit.

Ink jet printer using piezoelectric elements with improved ink droplet impinging accuracy

A solid-ink printing original plate which comprises a substrate and an image comprising an ink dot formed on the substrate, and which is prepared by a process comprising the steps of: melting a solid ink that is a solid at a room temperature; and jetting the melt of the solid ink onto a substrate to form an ink dot, wherein the ink dots that have solidified on the substrate have an ink dot height of at least 5 &mgr;m, and a ratio (aspect ratio) of the ink dot height to the minor axis size of the ink dot of from 0.05 to 0.5. Also disclosed is a process for producing the solid-ink printing original plate.

An ink jet recorder in which ink droplets having different, large and small diameters are produced, only the small diameter ink droplets of the ink droplets are selectively charged and deflected to record dots on a recording medium. The property of the ink employed in the recorder is selected to meet the condition K.ltoreq.N.sup.n .times.T.sup.m (N represents the viscosity of the ink, T represents the surface tension thereof, and n, m and K are positive constants, respectively), thereby maintaining the diameter of the small diameter ink droplets at a substantially constant value in the operation temperature range of the recorder.

Micro-dot ink jet recorder

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Hitachinaka, Japan

Masatoshi Sakata