Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1999-11-23
2001-07-24
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S048000, C347S065000, C347S067000
Reexamination Certificate
active
06264302
ABSTRACT:
BACK GROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharging head for discharging desired liquid by bubble generation induced by application of thermal energy to liquid, a head cartridge and a liquid discharging apparatus utilizing such liquid discharging head, and more particularly a liquid discharging head having a movable member capable of displacement by bubble generation, and a head cartridge and a liquid discharging apparatus utilizing such liquid discharging head.
The present invention is applicable to an apparatus such as a printer for printing on various recording media such as paper, yarn, fiber, textile, leather, metal, plastics, glass, timber, ceramics etc., a copying machine, a facsimile provided with a communication system, or a word process provided with a printer unit, and also to an industrial printing apparatus integrally combined with various processing apparatus.
In the present invention, the word “record” means not only provision, onto the recording medium, of a meaningful image such as a character or graphics but also provision of a meaningless image such as a pattern.
2. Related Background Art
There is already known an ink jet printing method, so-called bubble jet printing method, which achieves image formation by providing ink with energy such as heat to induce a state change in the ink, involving a rapid volume change (generation of a bubble), discharging ink from a discharge port by the action force based on such state change, and depositing thus discharged ink onto a recording medium. In the printing apparatus utilizing such bubble jet printing method, there are generally provided, as disclosed for example in the Japanese Patent Publication Nos. 61-59911 and 61-59914, a discharge port for ink discharge, an ink flow path communicating with the discharge port, and a heat generating member (an electrothermal converting member) provided in the ink flow path and constituting energy generating means for generating energy for discharging the ink.
Such printing method provides various advantages such as printing an image of high quality at a high speed with a low noise level, and obtaining a printed image of a high resolution, even a color image, with a compact apparatus, since, in the printing head utilizing such printing method, ink discharge ports can be arranged at a high density. For this reason, such bubble jet printing method is being recently utilized, not only in various office equipment such as printers, copying machines and facsimile apparatus but also in industrial systems such as textile printing apparatus.
With such spreading of the bubble jet printing technology into the products of varied fields, there have emerged various requirements to be explained in the following.
For example, for a requirement for improving the efficiency of energy, there is conceived optimization of the heat generating member, such as the adjustment of the thickness of the protective film. This technology is effective in improving the efficiency of propagation of the generated heat to the liquid.
Also for obtaining the image of higher quality, there have been proposed a driving condition for satisfactory liquid discharge, realizing a higher ink discharge speed and stable bubble generation, and an improved shape of the liquid flow path for realizing a liquid discharge head with a higher refilling speed of the discharged liquid into the liquid flow path.
Also for avoiding the loss of discharge energy, resulting from a backward wave which is a pressure wave generated at the bubble generation by the discharge energy generating element in the ink path and transmitted in the direction toward the liquid chamber opposite to the direction toward the discharge port, inventions utilizing a valve mechanism as a fluid resistance element are disclosed in the Japanese Patent Laid-open Application Nos. 63-197652 and 63-199972.
FIGS. 49A and 49B
are respectively an external perspective view and a cross-sectional view showing the liquid path structure of a conventional liquid discharging head.
As shown in
FIGS. 49A and 49B
, a backward wave preventing valve
1010
is provided at the upstream side in the ink flowing direction, namely at the side of a common liquid chamber
1012
, with respect to a heat action area (a space projected from the electrothermal converting member perpendicular to the plane) in the vicinity of a heat generating member
1002
provided in an ink path
1003
for generating bubble. Such backward wave preventing valve
1010
is to prevent the loss of the discharge energy, by so functioning as to prevent the movement of the ink toward the upstream side by the backward wave.
In such configuration, however, the suppression of a part of the backward wave by the preventing valve
1010
is not practical for the liquid discharge, as will be understood by the consideration of a situation of bubble generation in the ink path
1003
containing the liquid to be discharged.
Basically, the backward wave itself does not directly contribute to the liquid discharge. When the backward wave is generated in the ink path
1003
, a portion of the bubble pressure directly relating to the liquid discharge has already rendered the liquid dischargeable from the ink path
1003
as shown in FIG.
49
B. Consequently it will be apparent that the suppression of the backward wave, in particular a part thereof, does not give a significant influence on the liquid discharge.
Therefore, though the above-explained conventional head with the valve mechanism for preventing the backward wave at the bubble generation can improve the liquid discharging efficiency by a certain degree by the prevention of the backward wave propagating toward the upstream side, such configuration only intends to prevent the escape of a portion, toward the upstream side, of the discharging power generated at the bubble generation and is still insufficient in achieving significant improvement in the discharge efficiency and the discharge power.
On the other hand, in the bubble jet printing method, a deposit is generated on the surface of the heat generating member by the scorching or cognation of the ink since heating is repeated in a state where the heat generating member is in contact with the ink, and, depending on the kind of the ink, such deposit is generated in a large amount to render the bubble generation unstable, whereby satisfactory ink discharge may become difficult. For this reason there has been desired a method for achieving satisfactory discharge without denaturing the liquid to be discharged, even in case of a liquid which is susceptible to heat or is incapable of sufficient bubble generation.
In view of the foregoing points, a method of constituting the liquid for generating bubble by heat (bubble generating liquid) and the liquid to be discharged (discharge liquid) by different liquids and discharging such discharge liquid by transmitting the pressure of bubble generation to such discharge liquid is disclosed for example in the Japanese Patent Publication No. 61-59916 and Japanese Patent Laid-open Application Nos. 55-81172 and 59-26270. In these patents, there is employed a configuration of completely separating the ink or discharge liquid from the bubble generating liquid with a flexible membrane such as of silicone rubber thereby avoiding the direct contact of the discharge liquid with the heat generating member, and transmitting the pressure of bubble generation in the bubble generating liquid to the discharge liquid by the deformation of the flexible membrane. It is intended by such configuration to prevent generation of deposit on the surface of the heat generating member and to increase freedom in the selection of the discharge liquid.
However, in a head of the above-explained configuration where the discharge liquid and the bubble generating liquid are completely separated, the pressure of bubble generation, to be transmitted to the discharge liquid by the elongating deformation of the flexible membrane, is considerably absorbed by such flexible membra
Asakawa Yoshie
Imanaka Yoshiyuki
Kashino Toshio
Koyama Shuji
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stephens Juanita
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