Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-06-17
2002-05-07
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S045000
Reexamination Certificate
active
06382777
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid jet recording head used for a liquid jet recording apparatus that records on a recording sheet by discharging ink from the discharge ports of the orifice plate thereof.
2. Related Background Art
The liquid jet recording apparatus performs its recording on a recording sheet by discharging ink (recording liquid) as liquid droplets from the discharge ports arranged for the orifice plate of the liquid jet recording head. In accordance with the driving signals transmitted from the main body of the liquid jet recording apparatus, ink in each of the liquid flow paths is heated by each of the discharge energy generating elements which is arranged in each of the liquid flow paths so as to create the changes of state of ink for the formation of bubbles. Then, on the basis of the voluminal changes at the time of the bubble formation, ink is discharged from each of the discharge ports.
More specifically, as the discharge energy generating elements, the electrothermal transducing devices are used to generate heat when energized in accordance with the recording signals. The discharge energy generating elements are formed on a silicon substrate by the application of the thin film formation technologies and techniques in semiconductor field.
In general, the liquid jet recording head comprises a substrate having a plurality of discharge energy generating elements on it, and a ceiling plate that covers the upper part of the substrate. The ceiling plate comprises an orifice plate having the liquid flow paths (nozzles) that face the discharge energy generating elements, respectively, and the ink discharge ports; an ink liquid chamber for supplying ink to each of the liquid flow paths; and ink supply port through which ink is supplied to the ink liquid chamber.
The orifice plate is a sheet-type member of several tens to several hundreds of &mgr;m. For this sheet type member, a number of fine holes are formed as ink discharge ports. Then, as the method to form these fine holes efficiently in high precision, there are utilized a laser processing, an electroforming, a precision press work, a precision molding, or the like.
On the other hand, each liquid flow path (nozzle) is formed by means of a groove having a width of several tens of &mgr;m and a depth of several tens of &mgr;m. Many numbers of such grooves are formed at pitches of several tens of &mgr;m. In order to arrange these fine grooves to face the discharge energy generating elements in high precision, respectively, there is used for the manufacture thereof, precision molding, such as an injection molding, a transfer molding, an compression molding, an extrusion molding, an injection mold, ceramics injection; the fine laser processing, such as the excimer laser, the YAG laser; or the semiconductor thin film formation technologies and techniques, such as the silicon anisotropic etching, the photolithography, among others.
The ceiling plate is formed by means of the precision processing as described above. Particularly, the method that adopts the precision molding is extremely effective in that the member can be manufactured at lower costs, and in that the complicated configuration can be molded easily. So far, the ceiling plates are formed in various modes.
As the molding resin material, the resin material used, such as polysulfone, polyether sulfone, polyphenylene sulfide, denatured polyphenylene oxide, polypropylene, polyimide, or liquid crystal polymer (LCP) has an excellent resistance to ink.
For the molding of the ceiling plate, the most difficult techniques are to fill in the thinner thickness portion of the orifice plate, and transfer the fine portions of the liquid flow path walls stable as well. Therefore, the highly precise molding of the ceiling plate is performed by adopting various simulation techniques, such as the flow analysis or the precise mold machining techniques, at the same time, using a precise high-speed injection molding machine or a material having the high flowability for that purpose.
The injection molding is the most popular precision formation method. However, it is possible to implement the molding of a precise ceiling plate by the adoption of this method with the thorough control of the injection molding condition, such as the injection speed, the injection pressure, the dwell, the temperature adjustment of the metallic molds, the temperature adjustment of the resin, as well as with the structural devices of the metallic molds, such as degassing, the adjustment of dowel positions, or gate configuration, and further, by the positive utilization of the modern injection molding techniques, such as the pressure control in the interior of the metallic molds, the localized heating of the metallic molds, the vibration molding by use of the ultrasonic waves, or the injection molding using the compression in the interior of the metallic molds.
In this respect, the orifice plate may be molded integrally with the ceiling plate or molded separately from the ceiling plate. The structure of the ceiling plate in these cases may be selected arbitrarily depending on the component structure of the entire body, the structure of assembling apparatus, the method of laser processing, or the like. In either case, however, it is required to adopt a highly precise molding technique.
For example, the most difficult part of the ceiling molding is the filling of the molding resin into the fine portions such as the flow path walls. It is generally impossible to perform the sufficient filling in this portion just by the adoption of the injection processing step. In other words, for the injection processing step, the resin viscosity is made lower by the utilization of the temperature adjustment or sealing heat generation, and the flowability of the resin is enhanced. Then, before the resin is cooled down, it is filled in the metallic molds as quickly as possible. At this juncture, however, the condition of resin filling is still incomplete in the location where the resin flow is stagnated or at the corners, in the minute portions, or the like. Then, if the process proceeds to the step of dwelling, the pressure thus dwelled tends to act upon all the places in the interior of the metallic molds, and the transfer is performed to the portion where the filling has been insufficient in the injection step. As a result, if the filling is insufficient in the injection step, the pressure thus held tends to be concentrated on the locations where the filling is not sufficient, hence making it impossible to allow the pressure thus held to act upon the entire area of the interior of the metallic molds.
FIG. 1
is a view which schematically shows the conventional liquid jet recording head as described above. In
FIG. 1
, this liquid jet recording head comprises the substrate (hereinafter referred to as a heater board)
100
having the ink discharge pressure generating elements arranged on it, and the ceiling plate
500
having the irregular portion which constitutes the ink liquid chamber
600
that contains recording liquid (hereinafter referred to as ink) and the liquid flow paths (nozzles)
700
when the ceiling plate is bonded to the heater board
100
. Then, above the ink liquid chamber
600
, the ink supply port
1000
is arranged to be communicated with the ink liquid chamber
600
.
Also, in front of the liquid flow paths (nozzles)
700
, the orifice plate
400
having the ink discharge ports on it for discharging ink is integrally formed with the ceiling plate
500
or bonded to or coupled with the ceiling plate
500
so that the ink discharge ports are communicated with the liquid flow paths
700
.
The heater board
100
is adhesively fixed to the supporting substrate (hereinafter referred to as a base plate)
300
by the application of the bonding agent
306
or the like. The ceiling plate
500
is positioned and bonded so that the liquid flow paths (nozzles)
700
of the ceiling plate
500
are in agreement with the heater units
100
a
of the ink d
Naganuma Keizou
Watanabe Syunichi
Yamaguchi Yukuo
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Mouttet Blaise
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