Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-05-24
2002-08-13
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000
Reexamination Certificate
active
06431682
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head which is capable of discharging a liquid so as to form great many flying liquid drops, thereby effecting a desired recording operation. The present invention also relates to a method of manufacturing the liquid discharge head and a liquid discharge recording apparatus using the liquid discharge head. In particular, this invention relates to an orifice plate formed with a number of liquid discharge holes (herein after, referred to as orifice holes).
However, in the present invention, the term “recording” is used to mean not only an operation in which an image that is a character or a picture is recorded on a recording medium, but also another kind of operation for recording an image that is a pattern not having a certain specific meaning.
2. Description of the Related Art
In the past, there has been known an ink jet recording apparatus in which a sort of recording liquid (ink) is discharged through a number of orifice holes formed on a liquid discharge head so that a predetermined recording operation may be effected in a desired manner. In particular, such kind of ink jet recording apparatus has been considered to be an excellent recording apparatus since it can perform a recording operation at a high recording speed with only a low noise.
FIG. 14
is an explanatory perspective view which is used to serve as an example indicating a conventional liquid discharge head of the type mentioned in the above. In detail, the liquid discharge head shown in
FIG. 14
, comprises a substrate plate
1001
, a top plate
1002
and an orifice plate
1004
. The substrate plate
1001
has a plurality of heating elements
1005
which serve as energy generating elements for generating a necessary amount of energy needed for effecting a desired ink discharge. The top plate
1002
is provided on the upper surface of the substrate plate
1001
and has a plurality of grooves each serving as a liquid flowing path
1006
, located in positions corresponding to the heating elements
1005
. The orifice plate
1004
is provided in contact with the end faces of both the substrate plate
1001
and the top plate
1002
, and has a plurality of ink discharge orifice holes
1012
formed in positions communicated with the above ink flowing paths
1006
.
In more detail, the orifice holes
1012
formed on the orifice plate
1004
are extremely small in their sizes. In fact, how these orifice holes
1012
are formed will have an important influence on the discharge characteristic of the liquid discharge head. Namely, as far as the orifice plate
1004
of the liquid discharge head is concerned, since extremely small orifice holes
1012
are to be formed, it is required that the orifice plate
1004
as a whole should have an excellent workability (easy to be shaped into any desired shape). Further, since the orifice plate is in direct contact with the ink, the plate itself is required to have a sufficient ink resistance (not easy to be corroded by the ink).
As a material which can be used to form the orifice plate
1004
and which can satisfy the above requirements, it has been allowed to use a thin metal sheet made of SUS, Ni, Cr or Al. Also, it has been allowed to use one of the following several kinds of resin films whose thickness and properties are easy to achieve at a low cost. In detail, these resin films may be made of polyamide, polysulfone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, or polyproplene.
On the other hand, with the progress and development of the recording technique during recent years, it has been required that the recording operation should be performed at a high speed with a high precision. For this reason, the size (diameter) of each orifice hole is required to be further smaller and the orifice holes are needed to be arranged on the orifice plate with an increased density. In order to meet these requirements, there have been suggested various improved methods for forming the orifice holes. For example, when the orifice plate is made of a resin film, these orifice holes may be formed by virtue of laser treatment which is suitable for forming fine small holes. Further, when a metal is used to manufacture the orifice plate, the orifice holes may be formed with the use of an electrocasting method.
However, when the orifice holes are arranged with an increased density and each of the orifice holes has become smaller, a problem will be that orifice plate having orifice holes formed thereon will be difficult to be combined correctly with the liquid flow paths without forming any gaps. To cope with the above problem, Japanese Patent Laid-Open No. 2-187342 has disclosed an improved method in which an orifice plate made of a resin film is at first combined with a head main body which was previously formed by combining together a substrate plate and a top plate, then a laser treatment is used so as to form orifice holes on the orifice plate. Further, Japanese Patent Laid-Open No. 204048 has suggested another improved method shown in FIG.
15
. As shown in the drawing, an orifice plate
1024
made of a resin such as a dry film is at first softened by adding heat. The softened orifice plate
1024
is then pressed on to the combining surface of a head main body
1023
which was previously formed by combining together a substrate plate
1021
and a top plate
1022
, so that the orifice plate
1024
may be partially combined with a plurality of liquid flow paths
1026
formed on the head main body. Subsequently, a photolithography technique or a laser treatment is employed to form a desired liquid discharge head having a plurality of orifice holes
1032
located in positions corresponding to the liquid flow paths
1026
.
On the other hand, in order to ensure a stabilized direction for ink discharge, the diameter of each orifice hole should be made smaller along its ink discharge direction. Namely, it is preferred that each orifice hole be formed into a taper configuration. However, in the process of forming tapered orifice holes, it is preferred that a plurality of orifice holes are at first formed in the orifice plate, followed by combining the orifice plate on to the head main body. In fact, such kind of orifice plate is so formed that the portions surrounding each orifice hole is projected towards the head main body. In this way, by engaging the projected portions into the liquid flow paths of the head main body, the positioning of the orifice plate on to the head main body may be made easy.
However, there are at least the following problems associated with the above described conventional liquid discharge head.
Namely, in the above discussed method, an orifice plate is made of a resin film such as a dry film, the formed orifice plate is then softened by adding a heat. Subsequently, the softened orifice plate is then pressed on to the combining surface of a head main body, so that the orifice plate may be partially combined into a plurality of liquid flow paths formed in the head main body. In this way, although it is allowed to ensure a desired precision when the plurality of orifice holes are engaged with the liquid flow paths, there had been existing the following problems.
A first problem is that when the softened orifice plate is pressed on to the combining surface of the head main body, it will be difficult to control an amount of the resin invading into the liquid flow paths. Further, if the diameter of each orifice hole is extremely small and these orifice holes are arranged with a high density, an amount of resin invaded into the liquid flow paths will greatly affect the liquid discharge characteristic of the liquid discharge head, undesirably making a liquid discharge amount of one liquid flow path different from that of the other.
Moreover, when a resin film is used to form an orifice plate, the orifice holes are formed by virtue of laser treatment. However, if the laser treatment is conducted after the orifice plate has been combined on to the head main body, some
Ikegame Ken
Inada Genji
Ishinaga Hiroyuki
Kasamoto Masami
Osada Torachika
LandOfFree
Liquid discharge head, method of manufacturing the liquid... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid discharge head, method of manufacturing the liquid..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid discharge head, method of manufacturing the liquid... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2886663