Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-03-05
2002-08-27
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06439705
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an opening/closing mechanism provided for a liquid path for a liquid or a gas, and relates in particular to a liquid path opening/closing mechanism that can control the movement of a small quantity of liquid.
The following explanation will be given for a liquid path opening/closing mechanism that is used for the ink supply path of an ink-jet recording apparatus, such as an ink-jet printer, a facsimile machine or a copier. However, the present invention is not limited to this field, and pertains to a liquid path opening/closing mechanism that can also be employed for pharmaceuticals (including liquids, liquids in which powder has been dispersed, and gases), or for liquids having a high degree of purity (e.g., super pure water).
Furthermore, the liquid path opening/closing mechanism can also be used for air or other liquids (detergents, juice, spices or seasonings). Since the liquid path opening/closing mechanism is safe and light because in operation little pressure is required, and since power consumption is low, this mechanism is especially preferable for small toys (toy robots), a market that it is predicted will expand.
2. Related Background Art
For the following explanation, an ink-jet recording field is employed.
There are two types of ink-jet recording apparatuses: a continuous type and an on-demand type.
An ink-jet recording apparatus of a continuous type sequentially ejects ink through nozzles at high pressure, and changes the ink ejection direction on the fly en route to perform printing or to form images.
In a recording apparatus, an opening/closing mechanism is provided along an ink channel that supplies and halts the supply of ink at the start and at the end of printing. A large high pressure opening/closing mechanism, i.e., about 20 mm wide, 30 mm high and 20 mm long, is constructed of a strong material, such as metal, and has a complicated internal arrangement.
As is disclosed in Japanese Patent Application Laid-open No. 3-101944, since an on-demand ink-jet recording apparatus is designed for the ejection of ink droplets by an ink-jet ejection device, high pressure need not be exerted on the ink, and ink need only be supplied from an ink tank to an ink-jet head. Further, ink is supplied from the ink tank to the ink-jet head under a slight negative pressure (by using a head difference or providing a negative pressure exertion mechanism for the ink tank), so that ink leakage at the ink-jet head is prevented.
Therefore, for an on-demand arrangement, an ink channel that connects an ink tank to an ink-jet head need not be opened or closed to supply ink, but rather, all that is required is that a pipe be permanently provided, so that the ink-jet head can use head difference to suck up the necessary amount of ink. Either this, or merely an ink cartridge method is required in which an ink absorption member is stored as a negative pressure exertion member in an ink tank and ink is retained in and supplied from the member.
However, in recent applications wherein ink-jet recording apparatuses are employed to record high-resolution images, such as photo images, instead of simply supplying black and three other colors, Y (yellow), M (magenta) and C (cyan), six or seven different ink colors, including dark and light shades, and a special color or a processing liquid are required.
In addition, since the number of prints increases in consonance with an increase in the printing speed, a large amount of ink is required, and accordingly, a large ink tank is a necessity, while the current trend, in accordance with popular demand, is for recording apparatuses to be reduced in size, and for, in the arrangement of the components in the recording apparatus, the ink tank to be located higher than the ink-jet head, although conventionally such an arrangement is not employed.
Furthermore, according to one method, ink is stored separately from the ink-jet head in a large ink container, and a pipe is employed to carry the ink from the container to the ink-jet head.
According to this method, there is a need for ink to be stored in the liquid state at a location higher than the ink-jet head, and to be supplied as needed.
However, a small ink flow controller and associated parts are required, so that the configuration can cope with a small ink-jet head and seven colors of ink, for example.
A practically sized controller for this purpose is one that is about 15 mm in height, 15 mm in length and 15 mm in width, or smaller.
When a large amount of ink stored in an ink tank is to be supplied along a tube or a pipe to an ink-jet head, the ink flow controller must be located at the outlet port of the ink tank or along the route followed by the ink flow.
However, since in this configuration the ink-jet head is fixed, for the following reasons it is not always preferable for this configuration to be employed for a serial printing system in which the ink-jet head is moved horizontally.
Due to the inertia when an ink-jet head is moved horizontally, pressure fluctuation occurs such that more ink is supplied than is necessary and a negative pressure is generated on the suction side thereby making the ejection of ink from the ink-jet head unstable. It was found that no particular problem arose during the conventional printing of letters or characters, but that when a high-resolution image, such as a photo image, was printed, a slight variance or deterioration in printing quality was noted.
This problem is disclosed in detail in Japanese Patent Application Laid-open No. 7-251507. According to the disclosed configuration, an opening/closing device for controlling the flow of ink is located on the side of an ink-jet head, adjacent to the outlet of a pipe. For this configuration, it is preferable that the opening/closing device for controlling the ink flow be light and compact, and that it exhibit a superior response property. However, the valve of the opening/closing device in Japanese Patent Application Laid-open No. 7-251507 is opened or closed either in the same direction as or in the opposite direction to the flow of ink, although the structure of the opening/closing device is not described. Further, according to this publication, when the size of the opening/closing device is increased the size of the recording apparatus is also increased.
The objective of the invention is to provide an opening/closing device for an ink flow path that resolves the above problem.
Thus, the present inventor purposely searched for an ink joint having an opening/closing device that would satisfy the above described requirements, but found none. And then, because they had to prepare a conventional ink joint, the present inventors examined available conventional techniques that could be used for the production of an ink joint, but again, could not find a desirable technique.
Conventional techniques applied for the production of opening/closing devices are disclosed in Japanese Patent Application Laid-open No. 9-089146, No. 7-243542 and No. 5-026262. However, none of the devices described in these publications is an ink joint, equipped with an opening/closing device, that is small and light enough for four to seven of them to be mounted on an ink-jet head.
In
FIG. 5
is shown a conventional, comparatively simply structured opening/closing device that is disclosed in Japanese Patent Application Laid-open No. 7-243542, and in
FIG. 6
is shown another conventional, comparatively simply structured opening/closing device that is disclosed in Japanese Patent Application Laid-open No. 9-089146.
In
FIG. 5
, the opening/closing device is employed as a valve for preventing backflow in a water pipe, etc., and as is shown in
FIG. 5
, the valve comprises: a case
68
, a spring
62
, a moving core
63
, a coil
61
, a valve rod
70
, an operating valve body
71
, and a coil support member
72
.
In
FIG. 6
, the opening/closing device is a solenoid valve used for an oxygen cylinder for continuously supplying an adequate volume of oxygen to a hospital war
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