Ink jet printing apparatus
AssigneeRicoh Company, Ltd.
InventorHaruhiko Nagayama
Life of this patent
Estimating the term…
Abstract
Ink is recirculated from a reservoir (624) through an ink ejection head (100) and back to the reservoir (624) while it is being heated prior to actual printing to purge air from the ink and prevent erroneous ejection. The heat (100) has a nozzle assembly formed of a thick glass plate (184') and a thin plate (190') of monocrystalline silicone which is bonded to the glass plate (184'). Ink ejection ports (191') are etched through the silicone plate (190') which communicate with an ink chamber of the head (100) through passageways (185') formed through the glass plate (184').
Claims12
An ink jet printing apparatus including an ink ejection head having a chamber therein and at least one ink ejection port communicating with the chamber, an ink reservoir containing ink and pump means for pumping ink from the reservoir to the chamber, characterized by comprising;
- a passageway communicating with the chamber;
- valve means disposed in the passageway, the passageway leading from the chamber to the reservoir;
- and
- control means for opening the valve means at a start of operation of the apparatus to recirculate ink from the reservoir through the pump means, chamber and passageway back to the reservoir and subsequently closing the valve means, the passageway and said at least one ink ejection port being constructed such that, when the valve means is open, ink is not ejected from said at least one ejection port.
An ink ejection head including a block defining therein an ink chamber and being formed with a flat surface having a plurality of ink ejection passageways formed therethrough which communicate with the ink chamber, a thick flat plate being formed with ink ejection passageways therethrough conjugate to the ink ejection passageways of the flat surface, a thin flat plate fixed to the thick flat plate and being formed with ink ejection ports therethrough conjugate to the ink ejection passageways of the thick flat plate and fastener means for fastening the thick flat plate to the flat surface with the respective ink ejection passageways in alignment, a coefficient of thermal expansion of the thick flat plate being equal to a coefficient of thermal expansion of the thin flat plate.
Dependencies are inferred from the claim text.