Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-06-12
2002-12-31
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S049000, C347S065000, C347S093000
Reexamination Certificate
active
06499823
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording head adoptable for use in wide industrial fields, which is not only applicable to an office use printer, but also, to a printer capable of printing on cloths, coloring base plate for color filter use, and some other recording medium. The invention also relates to a method for manufacturing such ink jet recording head. More particularly, the invention relates to an ink jet recording head for which an elongation is designed for the discharge energy generating element substrate, as well as to a method for manufacturing such ink jet recording head.
2. Related Background Art
The structure of the conventional ink jet recording head itself for which an elongation is designed is substantially the same as the structure of the conventional ink jet recording head which is formed comparatively short. As shown in
FIG. 8
, on a base plate
106
, a heater board
204
is installed with discharge energy generating elements (not shown) such as electrothermal converting devices or the like, and on it, is further installed a ceiling plate
205
formed by silicon, resin, or the like which is provided with fine groove patterns thereon. The heater board
204
and the ceiling plate
205
are bonded or held down by use of a spring unit after a process of ceiling plate bonding. As shown in
FIG. 9
, the ceiling plate
205
is provided with an SUS rod which penetrates it in the longitudinal direction in order to secure the straightness thereof.
The ink, which is supplied through a filter (not shown) installed in a supply unit
201
for removing dust particles or the like, is allowed to flow in an SUS pipe
202
provided for a head cover
203
, and supplied from the ink jet recording head side into the ink flow paths which are formed by adhesively bonding the heater board
204
and the ceiling plate
205
. Then, the discharge energy generating elements provided for the heater board
204
supply discharge energy to ink in accordance with electric signals from the PWB
208
which is a printed base board for exchanging electric signals with a recording apparatus (not shown). In other words, when the discharge energy generating elements are electrothermal converting devices, ink is heated to be bubbled, and ink is discharged by means of pressure exerted by this bubbling.
In this way, recording is made by discharging ink to a recording medium. However, when the ink jet recording head operates continuously, the temperature of the head itself is caused to rise, and may produce unfavorable effect on recording in some cases. To counteract this, the base plate
106
is provided with heat radiating function, and it is formed by metallic material, such as aluminum alloy die-casting material, which has excellent mechanical property, machinability, and forgeability in addition to good thermal conductivity. Also, the surface of the base plate
106
is treated with anodized aluminum to provide erosion resistivity to prevent it from being eroded by ink.
Also, the recording apparatus having an ink jet recording head mounted thereon performs the recovery operation to remove ink adhering to the discharge surface by use of a blade to brash off the discharge surface on which discharge ports are formed to discharge ink from the ink jet recording head, thus stabilizing the discharge characteristics.
However, the elongated conventional ink jet recording head is structured so that the spring unit is added to hold down the ceiling plate and heater board with each other, besides the supply path for supplying ink, which is arranged above the ceiling plate. As a result, the number of components is increased, and the step of manufacturing processes is also increased eventually.
Also, in some cases, the countermeasures have not been taken sufficiently as to the straightness in the longitudinal direction, the prevention of thermal distortion that may take place on the structural members due to the temperature rise characteristic of an elongated head, as well as the deformation of head caused by the linear expansion difference of materials affected by the changes of environmental temperature. For example, the metallic material, such as aluminum, used for the base plate has a large thermal expansion coefficient, and is subjected to easier deformation by temperature changes. As a result, warping may occur in the mode of head in some cases.
Now, therefore, it is considered useful to select a material having a smaller thermal expansion coefficient, such as isotropic graphite, for the base plate material used for a printing head of as high as 600 dpi. The isotropic graphite has dually such characteristics as being strong against heat and chemicals, besides light in weight.
Nevertheless, the isotropic graphite has intergranular or inner texture defects or contains in it pores and microscopic cracks. As a result, the isotropic graphite has a high water absorption, and absorbs ink adhering to it eventually. Thus, on the surface of blading plane of the isotropic graphite which is brushed off by a blade, a considerable amount of ink is absorbed, and if the amount of ink thus absorbed reaches the critical state, ink is exuded, on the contrary, from the surface of the blading plane to wet it. Then, if the amount of ink which is brushed off exceeds the allowable amount after repeated recovery, ink cannot be brushed off completely, hence creating a problem that the recovery operation cannot be executed sufficiently.
Also, the intergranular binding power of isotropic graphite is small to make it easier to create carbon particles on the surface thereof, and processed plane as well, which of course brings about the creation of dust particles, and also, causes cut-offs or cracks when handling it for assembling or installation. Further, for that matter, a threaded female hole is subjected to being broken if screwed with an intensified value of torque, which necessitates a margin up for the strength of thread cutting.
Furthermore, beside the problems discussed above, the bubbles which are created in the ink supply path are stagnated at the filter portion or the ink supply or recovery efficiency of pressurized ink is reduced eventually.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink jet recording head for which the straightness is secured in the longitudinal direction without increasing the number of components, and a method for manufacturing such ink jet recording head.
It is another object of the invention to provide an ink jet recording head which does not impede the recovery operation thereof, and a method for manufacturing such ink jet recording head.
The ink jet recording head of the present invention comprises a substrate having the element surface provided with energy generating elements for generating energy to be used for discharging ink; a ceiling plate provided with the grooved surface having grooves to become ink passage corresponding to the energy generating elements, the grooved surface and the element surface being bonded to form the ink passage; a base plate for supporting the substrate from the side opposite to the element surface; and an ink supply member being in contact with the base plate at a contact portion, having the ink flow path wall face to be communicated with the ink passage. For this recording head, the base plate and the ink supply member pinch the substrate and the ceiling plate at the contact portion as a fulcrum so as to enable the base plate to press the substrate from the side opposite to the element surface, and the ink supply member to press the ceiling plate from the side opposite from the grooved surface.
For the ink jet recording head of the invention thus structure, the member that enables the ceiling plate and the substrate to be closely in contact, and the member for supplying ink are arranged to be commonly functional as an ink supply member. As a result, it becomes possible to omit the provision of any spring member to be used only for keeping the close contact of th
Miyazaki Hirotaka
Okazaki Takeshi
Omata Koichi
Shimamura Ryo
Watanabe Shun-ichi
Barlow John
Fitzpatrick ,Cella, Harper & Scinto
Stephens Juanita
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