Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-07-27
2003-10-28
Hilten, John S. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06637865
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head for discharging liquid and the driving method therefor, and a cartridge formed integrally with a liquid tank retaining liquid to be supplied to the liquid discharge head. The invention also relates to an image forming apparatus to form images on a printing medium. The invention is not only applicable to the printing apparatuses generally in use, but also, to a copying machine, a facsimile equipment provided with communication systems, and an apparatus having a printing unit, such a word processor, as well. Further, the invention is applicable to an industrial recording system having various processing apparatuses complexly combined therein, and also, to a textile printing apparatus and a processing apparatus such as to perform etching or the like.
Here, the term “printing” or “recording” used for the specification hereof means not only the formation of meaningful information, such as characters, graphics, but also, it is meant to include, in a broad sense, images, designs, patterns, or the like formed on a printing medium, as well as to include processes such as etching, irrespective of being meaningful or meaningless, or being apparent to be visually recognizable by eyesight. Also, the term “printing medium” means not only the paper sheet that is usually used for a printing apparatus in general, but also, it means cloth, plastic film, metallic plate, glass, ceramic, wood, leather, or the like, which is capable of receiving ink. The printing medium may be a sheet, a three-dimensional object, such as a spherical or cylindrical one, among some others. Further, the term “liquid” should also be interpreted in a broad sense as in the definition of the “printing (or recording)” as described above, and it is meant to include the one used for a printing medium to form images, designs, patterns, or the like, or used for etching process of a printing medium or ink processing (such as coagulating or insolubilizing coloring materials in ink to be used for a printing medium).
2. Related Background Art
An ink jet printer is the printing apparatus of the so-called non-impact printing type, which is capable of performing printing at higher speeds on various kinds of printing mediums. Therefore, with its feature that almost no noises are generated when printing, the ink jet printer is widely adopted as an apparatus that operates a printing mechanism for a word processor, a facsimile equipment, or a copying machine.
As the typical ink jet method, there is known the one that uses the electrothermal transducing elements that generate thermal energy as energy for discharging liquid, namely, ink droplets, such as processing liquid (hereinafter, these are collectively called “ink” for convenience sake in the specification hereof) which is used for adjusting the printability of ink with respect to ink itself or a printing medium. The ink jet method makes it possible to discharge small ink droplets from extremely fine discharge ports for printing on paper or some other printing medium.
Generally, the ink jet head uses electrothermal transducing elements comprising a driving system to form ink droplets, and a supply system to supply ink to the driving system. This head has the electrothermal transducing elements in a pressurized chamber. Then, the electric pulses which become printing signals are applied to them so that thermal energy is given to ink, and the abrupt changes occurring in the phases of ink at that time, that is, the bubbling pressures generated by vaporization, are utilized for discharging ink droplets.
Also, for the ink jet head using electrothermal transducing elements, there are known an edge shooter type where ink is discharged from the surface of the base plate in the arrangement direction of the electrothermal transducing elements, and a side shooter type where ink is discharged vertically from the surface of the base plate having the electrothermal transducing elements arranged thereon.
FIG. 48
is a view which shows the external appearance of an ink jet head of side shooter type in accordance with the background art hereof.
FIG. 49
is a view which schematically shows the structure thereof. FIG.
50
and
FIG. 51
are cross-sectional views which illustrate the structure thereof, taken in line
50
—
50
and line
51
—
51
in
FIG. 49
, respectively. In other words, for each of the heat generating base plates
12
where electrothermal transducing elements
11
are arranged at specific intervals, there are formed a plurality of discharge ports
13
for discharging ink, plural ink chambers
14
having these discharge ports
13
open therefrom, and a long and narrow ink supply port
15
for supplying ink to each of these ink chambers
14
. The ink supply port
15
which extends in the arrangement direction of electrothermal transducing elements
11
is generally cut and provided for the heat generating base plate
12
by means of sand blasting, anisotropic etching, or laser processing. Also, the electrothermal transducing elements
11
are connected with a wiring base plate
16
and each heat generating base plate
12
through the TAB (tape automated bonding) method for the application of electric signals for discharging ink. Further, each heat generating base plate
12
is fixed to a supporting member
17
, respectively.
In recent years, along with the significant reduction of costs and higher performance of a personal computer, the use of color printers has been promoted more. The printing head of a color printer of the kind should use ink of many colors, and it is arranged in plural numbers. For example, four heads are provided to use four colors, such as yellow, magenta, cyan, and black, and also, in order to make the apparatus smaller, each of the electrothermal transducing elements
11
is arranged on the heat generating base plate
12
at as smaller intervals as possible. For a highly precise printer having an ink jet head capable of performing at 600 dpi or 1,200 dpi, for example, it is required to form each of the discharge ports
13
and ink chambers
14
with an extremely high uniformity. As a result, it is generally practiced that each ink chamber positioned on either edge in the arrangement direction of the discharge ports
13
is regularly made a dummy ink chamber
14
d
, and that each of such dummy chambers is discriminated from the ink chambers
14
which are used for the actual printing operation.
Conventionally, as an ink jet head, there has been known the one which drives the driving elements, such as piezoelectric elements or electrothermal transducing elements, to discharge, liquid by the application of pressure or by means of bubble generation. Since an ink jet head of the kind deals with liquid, the arrangement is made to exhaust the liquid which has become overly viscous outside the head from the interior thereof. For this purpose, a suction recovery mechanism that uses a cap is arranged, and the pre-discharge (that is, idle discharges without any relations to printing signals) is performed to drive the driving elements, or a cleaning mechanism is provided for the ink jet printer to clean the surface of the discharge ports.
For an ink jet printer of the kind, a mode is adopted so that the “suction recovery”, “cleaning”, or “pre-discharge” is performed as the operational sequence therefor or a mode is adopted so that the “pre-discharge” is performed only after the “cleaning” is executed.
Meanwhile it has been known to make a color printer available by installing a plurality of ink jet heads thereon. However, irrespective of the case where a plurality of color ink jet heads are integrally formed or where these heads are individually arranged, liquids of different colors or different properties may be mixed between a plurality of ink jet heads in some cases.
Various means have been introduced in order to overcome these drawbacks. Particularly, as-among such means, a technique has been disclosed in the specification of Japanese Patent Application Laid-Op
Edamura Tetsuya
Hirosawa Toshiaki
Kawamura Shogo
Murakami Shuichi
Murata Takayuki
Feggins K.
Hilten John S.
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