Patent ID: 7837315

Claim:
A cavity unit for use in an ink-jet recording head, comprising: a plurality of plate members which are stacked on each other and which have (a) an ink-introducing passage which introduces an ink, (b) a filter portion which removes foreign matters from the introduced ink, (c) a first communication chamber and a second communication chamber, which are provided on either side of the filter portion and communicate with each other through the filter portion, (d) a plurality of nozzles, each of which ejects a droplet of the ink, (e) a plurality of individual ink chambers, each of which outputs the ink to a corresponding one of the nozzles, and (f) a common ink chamber which temporarily stores the ink to be supplied to said each individual ink chamber and comprises the first communication chamber disposed downstream with respect to an ink-flow path along which the ink flows from the ink-introducing passage to said each nozzle, the plate members including: an individual-ink-chamber plate having the individual ink chambers; a nozzle plate having the nozzles; a filter plate including the filter portion; and a guide-passage plate which is provided adjacent to one of opposite surfaces of the filter plate and which has, on an upstream side of the second communication chamber with respect to the ink-flow path, a guide passage which causes the introduced ink to flow, before the ink flows into the second communication chamber, in a first direction along said one of the opposite surfaces of the filter plate, wherein the plurality of plate members are stacked on each other, such that the filter plate and the guide-passage plate are provided between the individual-ink-chamber plate and the nozzle plate and wherein the plate members have a plurality of said ink-introducing passages which are provided in a staggered manner along a plane parallel to the plate members stacked on each other, such that a first group of said ink-introducing passages and a second group of said ink-introducing passages are arranged along a first straight line and a second straight line, respectively, which are parallel to each other and intersect the first direction, and the filter plate has a plurality of said filter portions which are distant from the ink-introducing passages, respectively, in the first direction, and which include a first group of said filter portions arranged along the first straight line, such that the filter portions of the first group are alternate with the ink-introducing passages of the first group, and a second group of said filter portions arranged along the second straight line, such that the filter portions of the second group are alternate with the ink-introducing passages of the second group.