Liquid discharge recording head

Details Liquid discharge recording head Liquid discharge recording head

2000-06-20

2001-12-04

Barlow, John (Department: 2853)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S063000

Reexamination Certificate

active

06325493

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge recording head used for a liquid discharge recording apparatus that records on a recording sheet by discharging ink from the discharge ports of an orifice plate. More particularly, the invention relates to a liquid discharge recording head the moldability of which is designed to be enhanced.
2. Related Background Art
The liquid discharge recording apparatus is the one that records on a recording sheet by discharging ink (recording liquid) as liquid droplets from the discharge ports of an orifice plate provided for a liquid discharge recording head. In accordance with the driving signals transmitted from the main body of the liquid discharge recording apparatus, ink is heated in each of the liquid flow paths by means of the discharge energy generating elements arranged in the liquid flow paths, respectively, thus making the change of states in ink to create bubbles. Then, with the voluminal changes at the time of bubbling, ink is discharged from the respective discharge ports.
More specifically, as discharge energy generating elements, the electrothermal transducing elements are used, which provide heating when energized in accordance with recording signals. The discharge energy generating elements are formed by the application of the thin film formation technologies and techniques which have been developed in the semiconductor field.
Generally, the liquid discharge recording head comprises a substrate having a plurality of discharge energy generating elements arranged thereon, and a ceiling plate that covers the upper portion of the substrate. The ceiling plate comprises liquid flow paths (nozzles) each corresponding to each of the discharge energy generating elements on the substrate; an orifice plate having ink discharge ports thereon; an ink liquid chamber to supply ink to each of the liquid flow paths; and an ink supply port through which ink is supplied to the ink liquid chamber.
The orifice plate is a sheet member having a thickness of several tens of &mgr;m to several hundreds of &mgr;m. Then, many numbers of precise holes are formed on this sheet member as ink discharge ports. As a method for forming the fine holes efficiently in high precision, a laser processing, an electrocasting, a precise press work, or a precise molding is utilized, among some others.
On the other hand, each of the liquid flow paths (nozzles) is formed by 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 arranged at pitches of several tens of &mgr;m. In order to arrange them in high precision to face each of the discharge energy generating elements, these fine grooves are produced by an injection molding, a transfer molding, a compression molding, an extrusion molding, a casing, a ceramics injection, or the like, or the excimer laser, the YAG laser or some other micro-laser process, or silicon anisotropic etching, photolithography, or some other semiconductor thin film formation techniques.
The ceiling plate may be formed by means of any one of those precise processing methods described above, but the precise molding method is, in particular, extremely effective in that the required members can be produced at lower costs, and that even a complicated shape can be molded with ease. Therefore, it has been possible to mold a ceiling plate in various modes up to now.
As the molding resin material, there is in use polysulfone, polyether sulfone, polyphenylene sulfide, modified polyphenylene oxide, polypropylene, polyimide, liquid crystal polymer (LCP), or some other resin material with excellent resistance to ink.
When molding a ceiling plate, the most difficult process is to fill up the thinner portions of the orifice plate, and transfer the extremely small portions of the liquid flow path walls. Therefore, the ceiling plate should be molded in high precision by the application of various simulation techniques, such as flowability analysis, while freely using precise die machining techniques, a high speed injection molder for precision processing, as well as by use of a highly flowable resin material.
Here, the orifice plate is either molded together with the ceiling plate or molded separately from the ceiling plate. The structure of the ceiling plate is, in either case, selected appropriately depending on the component structures as a whole, the structure of the assembling systems, the method of laser processing, or the like. In any case, however, a highly precise molding art should be adopted.
FIG. 8
is a view which schematically shows the conventional liquid discharge recording head of the kind. As shown in FIG.
8
. the liquid discharge recording head comprises the substrate (hereinafter referred to as a heater board)
100
provided with ink discharge pressure generating elements, the ceiling plate
500
having concave and convex portions, which is bonded to the heater board
100
to form the ink liquid chamber
600
and liquid flow paths (nozzles)
700
that contain recording liquid (hereinafter referred to as ink). On the upper portion of 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
, which is provided with the ink discharge ports for discharging ink, is formed together with the ceiling plate
500
or bonded to or coupled with the ceiling plate
500
. Thus, the ink discharge ports are communicated with the liquid flow paths
700
.
The heater board
100
is adhesively fixed to a supporting substrate (hereinafter referred to as a base plate)
300
by the application of a bonding agent
306
or the like. The ceiling plate
500
is positioned and bonded to the heater board
100
in such a manner that the heater unit
100
a
that serves as ink discharge energy generating elements arranged thereon is in agreement with the liquid flow paths (nozzles)
700
of the ceiling plate
500
. Then, the orifice plate
400
is arranged for the front end of the base plate
300
like an apron. Also, the ink liquid chamber
600
of the ceiling plate
500
receives ink from an ink tank (not shown) through the ink supply port
1000
.
If bonding agent, such as sealant or adhesives, is applied to bonding the liquid flow paths (nozzles)
700
and the heater board
100
. When the ink flow paths are formed for the liquid discharge recording head of the kind by bonding the liquid flow paths (nozzles)
700
with the heater board
100
together, the bonding agent tends to flow into the liquid flow paths (nozzles)
700
, and there is a possibility that the shape of the liquid flow paths (nozzles)
700
is changed or the liquid flow paths (nozzles)
700
are partly clogged. Therefore, at least the wall portion of the liquid flow paths should be bonded under pressure mechanically exerted.
Hereunder, the structure of such portion will be described. The heater board
100
and the ceiling plate
500
are positioned in the direction (indicated by an arrow E) which is in parallel to the ink discharge direction. The heater board
100
and the ceiling plate
500
are bonded, while the front end of the heater board
100
is allowed to abut against the orifice plate
400
. Then, the nails
507
of a pressure spring
900
, which are provided on the lower parts on both edges thereof, are inserted into the holes
307
arranged for the base plate
300
, respectively. Thus, the folded portions
507
a
of the nails
507
are hooked on the lower face of the base plate
300
. In this manner, the pressure spring
900
exerts mechanical pressure to the contacted portions from above the liquid flow path walls of the ceiling plate
500
.
In this manner, consequently, the liquid flow path walls of the ceiling palate
500
and the heater board
100
are closely in contact under mechanical pressure thus exerted.
Nevertheless, with the mechanical pressure of the kind, a load is given to the liquid flow path walls directl

Affiliated with

Also associated with

Rating

Liquid discharge recording head 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 recording head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid discharge recording head will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2602690