Kabushiki Kaisha Suwa Seikosha

Epson Corporation

Shinshu Seiki Kabushiki Kaisha

Seiko Epson Kabushiki Kaisha

Shinshu Seiki Kabushiki Kabushiki Kaisha Suwa Seikosha

Haruhiko Koto

Junichi Okada

Hiroshi Ishii

Kenji Sawada

An ink-on-demand type ink jet printer includes a printer head having at least one nozzle, pressure chamber and means for pressurizing an ink in the pressure chamber so as to effect ejection of an ink droplet from a nozzle to effect printing during a printing operation. The printer further includes a pump for pressurizing an ink in the printer head and a pump driver for driving the pump continuously for a predetermined period of time after the printing operation has ceased during which a small amount of ink is partially ejected from the nozzle. A nozzle cover is provided for selectively covering the nozzle, with the nozzle cover moving to cover the nozzle during the predetermined period of time when the pump driving means is operating while ink is partially ejected from the nozzle to prevent ink clogging during a no-print condition after the printing operation has ceased.

Ink jet printer of the ink-on-demand type

An ink-on-demand type ink jet printer including a printer head and an ink container. The printer head includes nozzles for ejecting ink droplets, pressure chambers for pressurizing ink therein and ink passageways for supplying ink from the ink container to the pressure chambers. The printer head is movable in a linear direction for printing across a sheet of recording paper. The ink container includes a vertical partition with the vertical partition having a wall disposed adjacent to an outlet of the ink container and extending substantially perpendicularly to the direction of movement of the printer head. The ink container includes an interior divided by the vertical partition into a main chamber of a first volume defined between one wall surface of the vertical partition and a wall surface of the ink container and an auxiliary chamber of smaller volume defined between the opposite wall surface of the vertical partition and another wall surface of the ink container. The ink is supplied to the nozzles from the auxiliary chamber with the level of ink in the auxiliary chamber being different than the level of ink in the main chamber.

An ink-on-demand type ink jet printer having a printer head. The printer head includes a substrate having a substantially planar surface and an opposing substantially planar surface and a vibratory plate having a cooperating substantially planar surface. The planar surfaces cooperate to define at least one nozzle, pressure chamber and ink supply passage therebetween. An ink container is integrally joined to the printer head with the ink container having a vent hole in an upper portion thereof. Separate means are provided for pressurizing the ink in the pressure chamber and for preventing air bubbles from entering the ink supply passage. The opposing substantially planar surfaces of the substrate define a wall of the ink container.

An ink-on-demand type ink jet printer includes an ink jet head assembly having a printer head and an ink container integrally joined to the printer head. The printer head includes a pressure chamber and ink supply and ejection flow passages communicating respectively therewith. The ink container includes therein a narrow air-bubble blocking tube opening directly into a lower portion of the interior of the ink container and which connects the ink supply flow passage to the ink container. A vent hole is defined in an upper portion of the ink container. The ink container includes a wall surface with the wall surface not trapping air bubbles, with a surface of the vent hole being coated with a defoaming agent.

An ink-jet printer head comprises a piezoelectric element, a pressurization chamber coupled to the piezoelectric element for containing ink therein, and a nozzle communicating with the pressurization chamber, the piezoelectric element being deformable upon application of a drive voltage V to increase the volume of the pressurization chamber, removal of the driving signal restoring the volume and ejecting ink from the nozzle. The vibratory system including the piezoelectric element has an acoustic capacitance Co selected with respect to the flow passage system including said nozzle, said pressurization chamber and an ink supply passage, so as to minimize the drive voltage V. Drive voltage is related to the capacitance Co, electrical capacitance cp of the piezoelectric element and pressure .psi. as follows: ##EQU1## K is a constant.

Low voltage ink-jet printhead

An on-demand type ink jet recording head. The ink jet recording head includes a substrate having a plurality of pressurization chambers of substantially rectangular configuration disposed thereon. Ink supply passages and nozzles are provided for each pressurization chamber. Each pressurization chamber also has a vibratory plate and a piezoelectric element which cooperate to change the volume of the pressurization chamber to cause ink to be ejected out of the respective nozzles thereof. Each nozzle has an equivalent nozzle length of 1 mm or less. Each pressurization chamber has a width of 1 mm or less and a length of 1 mm or more. The vibratory plate has a thickness of 200 .mu.m or less and the piezoelectric elements have a thickness of 200 .mu.m or less.

Ink jet recording head

An ink jet printing apparatus which ejects ink towards a recording medium. The apparatus includes a nozzle having a plurality of nozzles and a plurality of pressurization chambers. Each nozzle orifice is in fluid communication with one of the pressurization chambers. An ink supply system supplies ink to each of the pressurization chambers. Each pressurization chamber includes first and second transducers which selectively deform the respective pressurization chambers for ejecting ink out of the nozzles. Each first and second transducers are selectively driven by independent driving circuits.

Ink jet printing apparatus

An ink-jet printer comprises a piezoelectric element, a pressurization chamber coupled to the piezoelectric element for containing ink therein, and a nozzle communicating with the pressurization chamber, the piezoelectric element being deformable upon application of a drive voltage V to change the volume of the pressurization chamber for ejecting ink from the nozzle. The vibratory system including the piezoelectric element has an acoustic capacitance Co selected with respect to the flow passage system including said nozzle, said pressurization chamber and an ink supply passage, so as to minimize the drive voltage V. Drive voltage is related to the capacitance Co, electrical capacitance cp of the piezoelectric element and pressure .psi. as follows: ##EQU1## K is a constant.

In a substantially continuous process, solid ink is melted and deposited on a recording roller where it solidifies as a surface coating. Subsequently, heat is applied selectively and locally to portions of the roller to remelt the ink. A recording chart pressed against the moving roller picks up and retains the melted ink, thereby dots or segments of characters are formed on the recording chart. A plurality of heating means may be used so that printing in a dot matrix is made feasible.

Non-impact recording device

A small size ink jet printer includes a cover which presses against the ink nozzle openings when the printer is inoperative. The printer head is electrically driven but operation of the nozzle cover is at least partially performed manually. Particularly, the nozzle covering operation which needs a large force, is often manually performed to conserve energy and reduce component size. Circuits detecting and responding to an inadvertent failure to cover the nozzles are also provided.

Small size ink jet printer

An ink jet print head for projecting droplets of ink on demand includes a pressurization chamber including at least one wall defining a vibratory plate. A nozzle is open to the pressurization chamber and defines a fluid passage through which ink is ejected. A piezoelectric element is operatively coupled to the vibratory plate which is selectively energized to vibrate the wall thereby changing the volume of the pressurization chamber to eject ink through the nozzle. A vibratory system is defined by the piezoelectric element and the vibratory plate with the acoustic capacitance of the vibratory system being less than or equal to 9.times.10.sup.-17 m.sup.5 /N.

Ink jet print head

A small printer for printing characters on a printing medium especially adapted for use in a portable electronic calculator. The printer includes a frame having a carriage slidably mounted thereon for lateral displacement across the printing medium. An ink jet printing mechanism is carried on the carriage for selectively printing characters at predetermined positions along lines of the printing medium. A crank mechanism couples a motor to the carriage so that the printing mechanism can be translated across the printing medium. A printing position control circuit determines when the printing mechanism is in each predetermined printing position and selectively supplies a printing signal to the printing mechanism so that the printing mechanism will print a character at the selected predetermined positions.

Small printer

An ink jet head for a printer for ejecting liquid ink as droplets onto a recording medium, comprises a substrate having a nozzle, pressure chamber and passageway which are defined in a surface thereof, and a vibration plate supporting thereon a piezoelectric element, the substrate and vibration plate being formed of the same or substantially the same synthetic resins. The substrate and vibratrion plate have confronting surfaces fused and bonded together by a solvent, a doped cement, or with heat and pressure, or by ultrasonic welding.

Ink jet printer head

An ink supply system for an ink printer. The system includes an ink cartridge which supplies ink through a conduit to the print head of the printer. A bubble trapping device is disposed along the conduit and includes a porous member which prevents air bubbles from entering the nozzle of the print head. The air bubbles are held in a chamber defined in the bubble trapping device. Fluid passages in the chamber of the bubble trapping device allow for continuous feeding of the ink to the porous member for passage to the nozzle. A bubble detecting device may also be provided in the supply system.

Ink supply system for ink jet printers

A head for an ink-on-demand jet dot printer is highly integrated to provide a large plurality of closely spaced dots by combining more than one head of lesser dot density as components of a single unit. The dots from the separate component heads are interspaced on the print recording medium to provide characters of high quality. Commonality of elements provides for a miniaturized head. In another embodiment independent pressure chambers, channels and nozzles are formed on opposite sides of a common baseplate.

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Shiojiri, Japan

Haruhiko Koto