Epson Corporation

Kabushiki Kaisha Suwa Seikosha

Shinshu Seiki Kabushiki Kaisha

Seiko Epson Kabushiki Kaisha

Junichi Okada

Haruhiko Koto

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 for printing dots on demand on a recording medium has ink flow paths formed in a substrate. The ink paths include a pressure chamber, supply path and nozzle for discharging ink droplets, the nozzle terminating in an external front face of the printer head. A piezoelectric element acting on the pressure chamber to reduce chamber volume, causes an ink droplet to be ejected. Ink flow in the paths is perpendicular to the displacement of the piezoelectric element. The front face of the printer head is adapted to contour the ink layer which forms on the front face at rapid printing rates to assure that the droplets are ejected along a line which is a linear, parallel extension of the longitudinal nozzle axis. The design principles are applicable to printer heads having single or double rows of nozzles.

Ink jet printer head

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.

Growing community of inventors

Shiojiri, Japan

Junichi Okada