Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-05-16
2003-05-20
Hsieh, Shih-Wen (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S030000
Reexamination Certificate
active
06565186
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to an ink jet head, an ink jet apparatus and a method of recoverably activating in the apparatus.
In the case that the ink jet apparatus is kept unused for a long time or in the case that some specific ejecting ports among a plurality of ejecting ports is rarely used compared with other ejecting ports, there sometimes arises a malfunction that ink is improperly ejected from the ejecting ports. The reason why the foregoing improper ink ejection occurs consists in that water in ink is evaporated from the ejection ports or water in ink is evaporated from an ink chamber communicated with the ejection ports. In addition, there arises another malfunction that some ink droplets, some water droplets or dust particles adhere to the ejection surface of an ink jet head having a plurality of ejecting ports formed thereon, causing each ejected ink droplets to be pulled by the adhered foreign materials with the result that the ejecting direction is deviated from a predetermined one.
To prevent the foregoing malfunction from arising, a conventional ink jet apparatus is equipped with means as noted below to serve as a so-called ejection recovering system. This ejection recovering system is exemplified by e.g., preliminary ejecting means for discharging ink having an increased viscosity in a predetermined ink receiving medium prior to each recording operation, ink sucking means for removing some adhered materials from ejecting ports and a common ink chamber by sucking ink therefrom, ink sucking means for removing air bubbles introduced in ink at the time of ink reservoir replacement, and capping means for preventing water in ink from being vaporized from ejecting ports.
However, the conventional ejection recovering system has some following problems. Specifically, the ink jet apparatus is unavoidably fabricated at an increased cost attributable to necessity for disposing the preliminary ejecting means, the ink sucking means or the capping means. In addition, it is practically difficult to design and construct the ink jet apparatus with small dimensions because of necessity for reserving a space required for disposing the preliminary ejecting means, the ink absorbing means or the capping means. Additionally, it is necessary that an ink reservoir, a suction pump and associated pipings are arranged for executing preliminary ejection or ink suction, and moreover, accumulatively store waste ink in a certain container.
With respect to an ink jet apparatus capable of recording colored images, development works have been hitherto conducted for providing an ink jet apparatus including an ink jet head having plural groups of ejecting ports for black ink, yellow ink, magenta ink and cyan ink formed thereon, ink reservoirs independently disposed corresponding the groups of ejecting ports, a recovering cap common to the ejecting ports, and an ejection recovering unit. This kind of ink jet apparatus is often designed and constructed to record an image colored with two or three kinds of colors other than black. In this case, when a quantity of color ink per one dot is equalized to that of black ink, the diameter of a printed dot recorded on a recording medium is excessively enlarged. In view of the foregoing fact, when each dot is recorded with color ink, the diameter of each injecting port is reduced or the cross-sectional area of an injection nozzle is reducibly varied. To practice a so-called bubble jet recording system for ejecting liquid droplets by heating electrothermal transducers, a measure is taken such that a surface area of each heating elements is reduced or a distance between the heat generating element and an ejection orifice is changed to another one.
An ink jet apparatus using plural kinds of inks each having a different color and/or different depth of color employed therefor includes an ink jet head or an ink jet head unit having plural groups of ejecting ports formed therein, and the nozzle cross-sectional area of each ejecting port among a group of ejecting ports and the diameter of the same each varies from plural groups of ejecting ports. In addition, this ink jet apparatus includes an ejection recovering unit but this ejection recovering unit has the following shortages. Specifically, in the case that a magnitude of resistance against flowing of ink differs from each of plural groups of ejection ports and a sucking operation is achieved by a common recovering cap, a quantity of ink sucked by a single recovering operation each varies from plural groups
23
of ejecting ports. Consequently, a large quantity of ink is sucked by each ejection port among a group of ejecting ports having a large flow rate coefficient but a small quantity of ink is sucked by each ejection port among a group of ejecting ports having a small flow rate coefficient. If a quantity of ink sucked by each ejecting port during each sucking operation each varies from plural groups of ejecting ports, ink should be sucked from plural groups of ejecting ports in such a manner as to match with the quantity of ink sucked by the group of ejecting ports where a magnitude of resistance against flowing of ink is maximized, in order to remove air bubbles introduced in ink at the time of ink reservoir replacement or discharge ink having an increased viscosity in an ink path. For this reason, a quantity of ink in excess of a required quantity is sucked from other groups of ejecting ports and then uselessly wasted therefrom.
A flow rate coefficient of plural groups of ejection ports adapted to eject plural kinds of inks each having a different kind of color and/or different depth of color is substantially determined depending on a sum of the cross-sectional area of each ejecting ports involved in each of plural groups of ejecting ports. Obviously, the sum of the cross-sectional area of all the ejecting ports is determined based on the cross-sectional area of each ejecting port and the number of ejecting ports. Thus, in the case that plural groups of ejecting ports each having a different flow rate coefficient are subjected to ejection recovering treatment by utilizing the pressure in the fully capped state in consideration of the current technical tendency for reducing the number of components constituting the ink jet apparatus and simplifying the structure of the ink jet apparatus, the aforementioned malfunctions are liable to arise.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the aforementioned background.
An object of the present invention is to provide an ink jet head for an ink jet apparatus which assures that a quantity of uselessly consumed ink when the ink jet head is recoverably activated can be reduced.
Another object of the present invention is to provide an ink jet apparatus in which an ink jet head of the foregoing type is installed.
Further object of the present invention is to provide a method of recoverably activating an ink jet apparatus of the foregoing type.
According to a first aspect of the present invention, there is provided an ink jet head including plural groups of ejecting ports each having a different flow rate coefficient, wherein a capacity of an ink path communicated with a group of ejecting ports having a small flow rate coefficient is smaller than that of an ink path communicated with a group of ejecting ports having a large flow rate coefficient.
In addition, according to a second aspect of the present invention, there is provided an ink jet apparatus having an ink jet head of the foregoing type installed therein, wherein the ink jet head includes plural groups of ejecting ports each having a different flow rate coefficient in such a manner that a capacity of an ink path communicated with a group of ejecting ports having a small flow rate coefficient is smaller than that of an ink path communicated with a group of ejecting ports having a large flow rate coefficient, and sucking means is arranged for sucking ink from the plural group of ejecting ports in the state that the
Hattori Yoshifumi
Kaneko Mineo
Tosaka Yoichi
Tsutsumi Takayoshi
LandOfFree
Ink jet head, ink jet apparatus and method of recoverably... 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 head, ink jet apparatus and method of recoverably..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet head, ink jet apparatus and method of recoverably... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3083154