Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-04-12
2002-05-21
Beatty, Robert (Department: 2852)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000
Reexamination Certificate
active
06390604
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge method and a liquid discharge apparatus for discharging a desired liquid by generation of bubble by thermal energy or the like and, more particularly, to a liquid discharge method and a liquid discharge apparatus using a movable separation film arranged to be displaced utilizing the generation of bubble.
It is noted here that “recording” in the present invention means not only provision of an image having meaning, such as characters or graphics, on a recorded medium, but also provision of an image having no meaning, such as patterns, on the medium.
2. Related Background Art
One of the conventionally known recording methods is an ink jet recording method for imparting energy of heat or the like to ink so as to cause a state change accompanied by a quick volume change of ink (generation of bubble), thereby discharging the ink through an discharge port by acting force based on this state change, and depositing the ink on a recorded medium, thereby forming an image, which is so called as a bubble jet recording method. A recording apparatus using this bubble jet recording method is normally provided, as disclosed in the bulletin of Japanese Patent Publication No. 61-59911 or in the bulletin of Japanese Patent Publication No. 61-59914, with an discharge port for discharging the ink, an ink flow path in communication with this discharge port, and a heat-generating member (an electrothermal transducer) as energy generating means for discharging the ink located in the ink flow path.
The above recording method permits high-quality images to be recorded at high speed and with low noise and in addition, because a head for carrying out this recording method can have discharge ports for discharging the ink as disposed in high density, it has many advantages; for example, high-resolution recorded images or even color images can be obtained readily by compact apparatus. Therefore, this bubble jet recording method is used in many office devices including printers, copiers, facsimile machines, and so on in recent years and further is becoming to be used for industrial systems such as textile printing apparatus.
On the other hand, the conventional bubble jet recording method sometimes experienced occurrence of deposits due to scorching of ink on the surface of the heat-generating member, because heating was repeated in a contact state of the heat-generating member with the ink. In the case of the liquid to be discharged being a liquid easy to deteriorate due to heat or a liquid not easy to generate a sufficient bubble, good discharge is not achieved in some cases by formation of bubble by direct heating with the aforementioned heat-generating member.
Against it, the present applicant proposed a method for discharging an discharge liquid by generating a bubble in a bubble-generating liquid by thermal energy through a flexible film for separating the bubble-generating liquid from the discharge liquid, in the bulletin of Japanese Laid-open Patent Application No. 55-81172. The configuration of-the flexible film and the bubble-generating liquid in this method is such that the flexible film is formed in a part of nozzle, whereas the bulletin of Japanese Laid-open Patent Application No. 59-26270 discloses the configuration using a large film for separating the entire head into upper and lower spaces. This large film is provided for the purpose of being placed between two plates forming the liquid paths and thereby preventing the liquids in the two liquid paths from being mixed with each other.
On the other hand, countermeasures for giving a specific feature to the bubble-generating liquid itself and taking bubble-generating characteristics into consideration include the one disclosed in the bulletin of Japanese Laid-open Patent Application No. 5-229122 using a lower-boiling-point liquid than the boiling point of the discharge liquid, and the one disclosed in the bulletin of Japanese Laid-open Patent Application No. 4-329148 using a liquid having electric conductivity as the bubble-generating liquid.
However, the liquid discharge methods using the conventional separation film as described above are the structure of Just separating the bubble-generating liquid from the discharge liquid or simply an improvement of the bubble-generating liquid itself, and they are not at the level of practical use yet.
SUMMARY OF THE INVENTION
The present inventors have researched mainly liquid droplets discharged in discharge of liquid droplet using the separation film and came to the conclusion that the efficiency of liquid discharge based on formation of bubble by thermal energy was lowered because of intervention of change of the separation film, so that it had not been applied to practical use.
Therefore, the present inventors came to study the liquid discharge method and apparatus that achieved the higher level of liquid discharge while taking advantage of the effect by the separation function of the separation film.
The present invention has been accomplished during this study and provides breakthrough liquid discharge method and apparatus that are improved in the discharge efficiency for discharge of liquid droplet and that stabilize and enhance the volume of liquid droplet discharged or the discharge rate.
The present invention can improve the discharge efficiency in the liquid discharge method and apparatus using a liquid discharging head comprising a first liquid flow path for discharge liquid in communication with an discharge port, a second liquid flow path containing a bubble-generating liquid so as to be capable of supplying or moving the bubble-generating liquid and having a bubble-generating region, and a movable separation film for separating the first and second liquid flow paths from each other, and having a region of displacement of the movable separation film upstream of the discharge port with respect to a direction of flow of the discharge liquid in the first liquid flow path.
Particularly, the present inventors found out the following problem. When the space becoming the bubble-generating region is a small space, that is, when the bubble-generating region itself, though being formed on the upstream side of the discharge port with respect to the direction of flow of the discharge liquid, has the width and length close to those of the heat-generating portion, in generation of bubble in the bubble-generating region, the movable film is displaced with generation of bubble only in the perpendicular direction to the direction of discharge of the discharge liquid, so that sufficient discharge rates cannot be attained. This resulted in the problem that the efficient discharge operation was not achieved. Noting that the cause of this problem is that the same bubble-generating liquid is always used repetitively only in the small space closed, the present invention also realizes the efficient discharge operation.
A first object of this invention involves a liquid discharging method for discharging liquid from a discharge port by displacing, using a bubble generated at a bubble generation area for generating the bubble in the liquid, a movable separation film. That film substantially separates from each other a first liquid flow path communicating with the discharge port for discharging the liquid and a second liquid flow path having the bubble generation area. This method includes the steps of generating a bubble in the bubble generation area and displacing the movable separation film substantially without stretch in accordance with the generating step to discharge liquid from the discharge port.
A second object of this invention concerns a liquid discharging apparatus having a first liquid flow path communicating with a discharge port for discharging liquid, a second liquid flow path having a bubble generation area for generating a bubble in the liquid, and a movable separation film substantially separating the first from the second liquid flow paths. The movable separation film is displaced by the bubb
Asakawa Yoshie
Ishinaga Hiroyuki
Kashino Toshio
Kudo Kiyomitsu
Shimazu Satoshi
Beatty Robert
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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