JP2680303B2 - Color inkjet head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color inkjet head in a charge amount control type multi-nozzle color inkjet recording apparatus. 2. Description of the Related Art Generally, in a multi-nozzle color inkjet head having a plurality of colors of ink, since the viscosity coefficient of each ink is different, the cutting phase of the jet flow ejected from the nozzle group of each ink color is different and a good image is obtained. In order to obtain it, there is a drawback that the charging timing of each ink color has to be changed for each ink. In addition, Japanese Patent Laid-Open Publication No. 54-88125 discloses a nozzle in which the lengths of the nozzles arranged at each end of the nozzle row and the nozzles arranged in the center are changed. Is for compensating the speed fluctuation caused by the difference in aerodynamic drag of the ink flow out from the plurality of nozzle rows, and is not intended to make the cutting time of the plurality of color inks uniform. The present invention has been made in view of the above situation, and in a multi-nozzle color inkjet head having ink chambers of a plurality of colors, uniform cutting time for ink droplet generation of a plurality of colors of inkjet is provided, and good printing is achieved. It was made for the purpose of obtaining a photographed image. In order to achieve the above object, the present invention is a color ink jet head having a plurality of ink liquid chambers for ejecting ink of a plurality of colors and nozzles provided corresponding to the ink liquid chambers. Color inkjet head
The multi-nozzle plate is composed of an ink ejecting unit and an ink ejecting unit, and the ink ejecting unit changes the nozzle shape so as to compensate for the non-coincidence of the viscosity coefficients of a plurality of colors of ink, and is formed on one common plate. It is characterized by being. Hereinafter, a description will be given based on an example of the present invention. FIG. 1 is a perspective view for explaining an embodiment of a color ink jet head according to the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIGS. FIG. 3 is an enlarged sectional view of a nozzle plate, in which 10 is a nozzle plate in which nozzle groups 11a to 11d for inks of a plurality of colors, for example, yellow, magenta, cyan, and black inks are arranged in the longitudinal direction, and 20 is the nozzle group. Nozzle substrates 30 provided with ink chambers 21a-d corresponding to 11a-d are manifolds having elongated openings 30 'extending in the nozzle row direction, and ink inflow valves 31a-31a-
Ink inflow passages 32a-d leading to d and ink outflow passages 34a-d leading to ink outflow valves 33a-d are formed, and as shown in FIG. The generator 40 is held by the rubber material 50. Reference numeral 41 denotes a notch formed in the longitudinal direction of the vibration generating section 40 so as to obtain uniform vibration displacement in the nozzle row direction, and 60 denotes an excitation source. FIG. 3A is a cross section of the nozzle plate 10 in which the nozzle lengths L _{11 a} to ₁₁ d are changed for each ink nozzle group _{11 a} to ₁₁ d so as to previously compensate for the difference in the viscosity coefficient of each ink. FIG. 2B is a cross-sectional view when the nozzle diameters D _{11 a} to ₁₁ d are similarly changed for each ink nozzle group _{11 a} to ₁₁ d, and such a nozzle plate has a small difference in diameter and length. From the viewpoint of being integrally formed on one nozzle plate 10, a glass thin tube or an optical fiber having an etchable core portion is preferable. Effects As is clear from the above description, according to the present invention, the nozzle shape is configured to compensate for the difference in the viscosity coefficient of the multi-color ink,
That is, since the nozzle length and the nozzle diameter are changed in advance, it is possible to make the ink cutting time of the plural color inks uniform and obtain a good image.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view for explaining an embodiment of a color inkjet head according to the present invention, and FIG. 2 is a perspective view of FIG.
A sectional view taken along line II-II and FIGS. 3A and 3B are enlarged sectional views of the nozzle plate, respectively. 10 ... Nozzle plate, 11a-d ... Multiple color ink nozzle group, 20 ... Nozzle substrate, 21a-d ... Ink liquid chamber, 30 ...
Manifolds, 31a-d ... Ink inflow valves, 32a-d ...
Ink inflow path, 33a-d ... Ink outflow valve, 34a-d.
Ink outflow path, 40 …… Vibration generator, 41 …… Notch, 50 ……
Rubber material, 60 ... Excitation source.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takuro Sekiya               1-3-6 Nakamagome, Ota-ku, Tokyo               Ricoh Company (72) Inventor Stephen J. Volma               United States California               95131 San Jose Concourse Drive                 2071 Ricoh Systems Inc.               Inside                (56) References JP-A-57-12656 (JP, A)                 JP-A-61-261058 (JP, A)

Claims (1)

(57) [Claims] What is claimed is: 1. A color inkjet head comprising a plurality of ink liquid chambers for ejecting a plurality of colors of ink, and nozzles provided corresponding thereto, the color inkjet head comprising an ink ejecting unit and an ink ejecting unit. The ink ejecting unit is a multi-nozzle plate which is formed on a common single plate by changing the nozzle shape so as to compensate for the non-coincidence of the viscosity coefficients of a plurality of colors of ink. Inkjet head.