Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-01-14
2001-09-18
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06290347
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for delivering ink, more particularly to a print head for an ink jet printer, provided with a series of ink delivery nozzles which can be actuated selectively when printing a sheet of paper or the like. The present invention also relates to an ink jet printer provided with such a device.
One known device of this kind has a substantially triangular base plate, the apex of which is directed towards the sheet for printing, and the oblique sides of which are provided with a number of ink ducts covered by a foil and extending to near the bottom or head end of the base plate, where they extend in the form of ink tunnels through the base plate towards the head surface. There the nozzles of the ink tunnels are covered by a nozzle plate, possibly in the form of a foil, in which a hole is made for each ink passage. Piezo-electric elements are disposed at the location of the foil over the ducts on the oblique sides and can be actuated selectively in order to briefly press on the foil above a duct and thus create a pressure pulse in the ink there, so that a droplet is delivered from the associated nozzle.
U.S. Pat. No. 4,364,067 discloses a print head attachment having a substantially rectangular base plate, the top of which is provided with an ink inlet connected to an ink reservoir and terminating in an ink distribution chamber to which are connected a number of ducts formed in the two sides. These ducts converge with an arc in the plane of the associated side to a number of downwardly directed ink delivery nozzles provided in a nozzle plate disposed in the base plate head surface situated transversely of the sides. The ink delivery nozzles form a Y-shaped duct, the branches of which extend to ducts on the opposite sides of the base plate.
The ducts themselves are covered by a vibrating plate on which an electrode is mounted. Provided on the electrode, at the location of the pressure chambers, are piezo-electric elements, which are also provided with an electrode. Selective actuation of the piezo-electric elements causes the vibrating plate to be pressed in locally and the volume of the pressure chamber in the required duct is reduced so that a specific quantity of ink is propelled through said duct to the associated ink delivery nozzle.
A disadvantage of the known printer heads is that the ink-tight layers adjoin one another at an angle so that sealing may be locally inadequate.
SUMMARY OF THE INVENTION
From one aspect, the object of the present invention is to provide an improvement in this respect.
To this end, the present invention provides a device for delivering ink to a sheet of paper or the like, comprising a body with sides and a head end disposed at an angle to the sides and containing an inlet for the ink originating from a reservoir. A plurality of ink delivery nozzles are provided at the head end, and a plurality of ink passages extend between the inlet and the ink delivery nozzles and are located on that side of the body as the ink passages in the form of ducts where ink propulsion means, e.g. piezo-electric elements selectively operate. An ink-tight layer, such as a suitable foil, extends between the piezo-electric elements and the ducts, whereby the ends of the ink passages situated at the ink delivery nozzles are covered by an ink-tight layer in which the ink delivery nozzles are formed.
The body between the head end and the adjoining side in which the ink passages are provided is formed with a curved transition zone. The presence of the curved transition zone makes it possible to continue the ink-tight layer at the location of the head surface and/or at the location of the ducts in the side or sides, at least as far as providing a smooth connection between the ink-tight layer of respectively one side or head surface, without the layer having to extend over a gap such as a sharp angle, where the layer may be permanently deformed due to kinking and thus would not provide adequate sealing.
In the known print head attachments, separate covers are used at the location of the ducts at the piezo-electric elements and at the location of the delivery nozzles. The manufacture of the print head attachments thus requires a double operation which has to be carried out with great accuracy. From a further aspect, the object of the present invention is to provide improvement in this respect. To this end, according to the present invention, the ink-tight layer at the location of the ink propulsion means forms a unit with the ink-tight layer at the location of the ink delivery nozzles. Thus a single ink-tight layer is sufficient for the head surface and side. The manufacture of the print head attachment is thus greatly simplified and more easily controlled.
This advantage is enhanced if the body is provided with two opposite sides in which the ink passages are provided, a curved transition zone being provided at both sides, wherein the ink-tight layer extends as a unit over both sides and over the head end.
As a result of the curved shape of the transition zones it is also possible to continue the ducts in a simple manner as far as the ink delivery nozzles. Advantageously, the associated side and the adjoining head end of the body are covered by the same ink-tight layer, so that this layer can also serve outside the piezo-electric elements as a boundary of the ink passages.
Preferably, the ink-tight layer continues over the inlet where it is provided with one or more filter passages by means of which the ink-tight layer, i.e., at least that object, is given a further function and a filter can also be provided in one operation.
Advantageously, the ink-tight layer upstream of the ink propulsion means is provided with filter passages for passing and filtering ink to the ink ducts, so that the ink is filtered at the upstream end of the ink ducts.
Preferably, the ink ducts are continued in the upstream direction as far as the location of the filter passages and the ink-tight layer performs the function of outer boundary over the complete length of the ducts, from the inlet to the delivery nozzles.
REFERENCES:
patent: 4364067 (1982-12-01), Koto et al.
patent: 5604522 (1997-02-01), Miura et al.
patent: A1-2340855 (1975-02-01), None
patent: A2-0721839 (1996-07-01), None
patent: A1-0854038 (1998-07-01), None
English language abstract of Japanese reference 55/067476, K. Hiromichi, “Ink Jet Head”, May 21, 1980.
Hollands Peter Joseph
Stolk Hendrik Jan
Birch & Stewart Kolasch & Birch, LLP
Le N.
Nghiem Michael
Oce--Technologies B.V.
LandOfFree
Ink jet array does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet array, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet array will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2483230