Liquid jet recording head having a layer of a resin composition curable with an active energy ray

A liquid jet recording head has a liquid passage communicated to the discharging outlet of the liquid which is formed with a resin composition cured with an active energy ray. The resin composition to be cured comprises (i) a heat-crosslinkable linear copolymer containing 5-30 mol % of a monomer of formula I and 5-50 mol % of a monomer of formula II ##STR1## and (ii) a monomer having an ethylenically unsaturated bond.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a liquid jet recording head, more particularly to 
a recording head for generation of small droplets of a liquid for 
recording to be used in a liquid jet recording system in which recording 
is performed by generating small droplets of a liquid for recording such 
as ink, etc., and attaching them onto a recording medium such as paper. 
2. Related Background Art 
The liquid jet recording system which performs recording by generating 
small droplets of a liquid for recording such as ink, etc., and attaching 
them onto a recording medium such as paper is attracting attention as the 
recording system which generates extremely little to neglegible noise 
during recording, is capable of high speed recording and enables recording 
on plain paper without requiring any special treatment such as fixing. 
Various types of this system have been actively studied. 
The recording head portion of the recording device to be used in the liquid 
jet recording system generally consists of an orifice for discharging a 
liquid for recording (liquid discharging outlet), a liquid passage 
connected to the orifice and having a portion at which the energy for 
discharging the liquid for recording acts on the liquid for recording, and 
a liquid chamber for storing the liquid for recording to be fed into the 
liquid passage. 
The energy for discharging the liquid for recording during recording is 
generated in most cases by means of a discharge energy generating element 
of various types such as heat generating element, piezo-electric element, 
etc., which is arranged at a predetermined position at the portion where 
the discharging energy is permitted to act on the liquid for recording 
which constitutes a part of the liquid passage (energy acting portion). 
As a method for preparing the liquid jet recording head with such a 
constitution, there have been known, for example, a method comprising the 
steps of forming fine grooves on a flat plate of glass, metal, etc., by 
cutting or etching and bonding another appropriate plate onto the flat 
plate having such grooves formed thereon to thereby form liquid passages, 
or a method comprising the steps of forming groove walls of a cured 
photosensitive resin on a substrate having a discharging energy generating 
element arranged thereon according to a photolithographic step to provide 
grooves for the liquid passages on the substrate and bonding another flat 
plate (covering) onto the grooved plate thus formed to thereby form liquid 
passages (for example, Japanese Laid-open Patent Application No. 
57-43876). 
Of these methods for preparation of the liquid jet recording heads, the 
latter method employing a photosensitive resin is more advantageous than 
the former method in that liquid jet recording heads can be provided with 
better quality and cheaper cost because it enables fine working with 
better precision and better yield and mass production with ease. 
As the photosensitive resin to be used in preparation of such recording 
heads, there have been employed those used for pattern formation in 
printing plates or printed-wiring or those known as the photocurable 
coating materials or adhesives to be used for glass, metal, ceramics, etc. 
Also, for working efficiency, dry film type resins have been primarily 
utilized. 
In the recording head employing a cured film of a photosensitive resin, in 
order to obtain excellent characteristics such as high recording 
characteristic, durability and reliability, etc., the photosensitive resin 
to be used for the recording head is required to have the following 
characteristics. 
(1) particularly excellent adhesion between the cured film and a substrate; 
(2) excellent mechanical strength and durability, etc., when cured; and 
(3) excellent sensitivity and resolution during patterning by use of 
pattern exposure light. 
However, under the present situation, none of the photosensitive resins 
used for formation of the liquid jet recording head hitherto known in the 
art satisfy all of the above requisite characteristics. 
To describe in more detail, those employed for pattern formation in 
printing plates, printed-wirings, etc., as the photosensitive resin for 
recording head are inferior in adhesion or close contact with glass, 
ceramics, plastic film, etc., to be used as the substrate, although they 
are excellent in sensitivity and resolution, and also insufficient in 
mechanical strength and durability when cured. For this reason, at the 
stage of preparation of recording heads, or in the course during usage, 
there is involved the drawback that deformation of the resin cured film or 
peel-off from the substrate or damages are liable to occur, which may 
cause marked impairment in the reliability of the recording head such as 
lowering in recording characteristics by impeding the flow of the liquid 
for recording in the liquid passages or making the liquid droplet 
discharging direction unstable. 
On the other hand, those which are known as photocurable type coating 
materials or adhesives to be used for glass, metals, ceramics, etc., 
although having advantages of excellent close contact or adhesiveness with 
the substrate formed of these materials and also satisfactory mechanical 
strength and durability obtained when cured, are inferior in sensitivity 
and resolution and therefore require an exposure device of higher 
intensity or an exposure operation of longer time. Further, their inherent 
characteristics can not afford providing precise and high density pattern 
with good resolution, whereby there is involved the problem that it is not 
suitable for a recording head for which minute precise working is 
particularly required. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished in view of the problems as 
described above and an object of the present invention is to provide a 
liquid jet recording head having a liquid passage wall comprising a resin 
cured film satisfying all of the requisite characteristics as mentioned 
above, which is inexpensive, precise, high in reliability and excellent in 
durability. 
Another object of the present invention is to provide a liquid jet 
recording head having a constitution of which the liquid passage is 
minutely worked with good precision and good yield. 
It is also another object of the present invention to provide a liquid jet 
recording head which is high in reliability and excellent in durability 
even when formed into multi-orifices. 
According to the present invention, there is provided a liquid jet 
recording head, having a liquid passage communicated to the discharging 
outlet of the liquid provided on a substrate surface, said passage being 
formed by subjecting a layer of a resin composition curable with an active 
energy ray to a predetermined pattern exposure with the use of said active 
energy ray to form a cured region of said resin composition and removing 
the uncured region from said layer. 
Said resin composition comprising (i) a heat-crosslinkable linear copolymer 
containing 5 to 30 mol % of a monomer represented by the formula I shown 
below and 5 to 50 mol % of a monomer represented by the formula II shown 
below, as the copolymer constituents: 
##STR2## 
(wherein R.sup.1 represents hydrogen or alkyl or hydroxyalkyl group having 
1 to 3 carbon atoms; R.sup.2 hydrogen or alkyl or acyl group having 1 to 4 
carbon atoms which may have a hydroxy group; R.sup.3 hydrogen or alkyl 
group having 1 to 3 carbon atoms; R.sup.4 divalent hydrocarbon group which 
may have internally an ether bond and may also be substituted with halogen 
atoms; and R.sup.5 alkyl having 3 to 12 carbon atoms or phenylalkyl group 
or phenyl group), and (ii) a monomer having an ethylenically unsaturated 
bond.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, the liquid jet recording head of the present 
invention is described in detail. 
FIG. 1 is an embodiment of the liquid recording head of the present 
invention, FIG. 1A showing a perspective view of the main portion thereof 
and FIG. 1B showing a sectional view of FIG. 1A cut along the line C--C'. 
The liquid jet recording head comprises basically a substrate 1, a resin 
cured film 3H provided on the substrate 1 and subjected to patterning to a 
desired shape and a covering 7 laminated on the resin cured film 3H, and 
these members form an orifice 9 for discharging a liquid for recording, 
liquid passages 6-2 communicated to the orifices 9 and having the portions 
at which the energy for discharging the liquid for recording acts on the 
liquid for recording, and a liquid chamber 6-1 for storing the liquid for 
a recording to be supplied to the liquid passages 6-2. Further, at the 
thru-hole 8 provided on the covering 7, a feeding pipe 10 for feeding the 
liquid for recording from outside of the recording head into the liquid 
chamber 6-1 is bonded. In FIG. 1A, the feeding pipe 10 is omitted. 
During recording, the energy for discharging the liquid for recording is 
generated by applying discharging signals as desired to the discharge 
energy generating elements 2 of various types such as heat-generating 
elements, piezoelectric elements, etc., arranged at predetermined 
positions in the portions for imparting the discharging energy on the 
liquid for recording constituting a part of the liquid passages 6-2 
through wirings (not shown) connected to these elements 2. 
The substrate 1 constituting the recording head of the present invention 
comprises glass, ceramic, plastic or metal and the energy generating 
elements 2 are arranged in a desired number at predetermined positions. In 
the embodiment of FIG. 1, two energy generating elements are provided, but 
the number and arrangement of the heat generating elements are determined 
depending on the desired constitution of the recording head. 
On the other hand, the covering 7 comprises a flat plate of glass, ceramic, 
plastic or metal and is bonded onto the resin cured film 3H by fusion or 
adhesion by use of an adhesive, and it is also provided with a thru-hole 8 
for connecting a feeding pipe 10 at a predetermined position. 
In the recording head of the present invention, the resin cured film 3H 
subjected to patterning to the predetermined shape constituting the walls 
of the liquid passages 6-2 and the liquid chamber 6-1 is obtained by 
subjecting a layer comprising a resin composition with the composition as 
described below on the substrate 1 or on the covering 7 to patterning 
according to a photolithographic step. The resin cured film 3H may also be 
subjected to patterning as integrated with covering 7 formed with the 
resin composition. 
The resin composition to be used for formation of a resin cured film 
provided on a substrate for constituting such a portion which becomes at 
least the liquid passage is an active energy ray-curing resin composition 
comprising: (i) a heat-crosslinkable linear copolymer containing 5 to 30 
mol % of a monomer represented by the formula I shown below and 5 to 50 
mol % of a monomer represented by the formula II shown below, as the 
copolymer constituents: 
##STR3## 
(wherein R.sup.1 represents hydrogen or alkyl or hydroxyalkyl group having 
1 to 3 carbon atoms; R.sup.2 hydrogen or alkyl or acyl group having 1 to 4 
carbon atoms which may have a hydroxy group; R.sup.3 hydrogen or alkyl 
group having 1 to 3 carbon atoms; R.sup.4 divalent hydrocarbon group which 
may have internally an ether bond and may also be substituted with halogen 
atoms; and R.sup.5 alkyl having 3 to 12 carbon atoms or phenylalkyl group 
or phenyl group), and (ii) a monomer having an ethylenically unsaturated 
bond. The resin composition has good adhesion to a substrate comprising 
glass, plastic, ceramic, etc., particularly when formed into a cured film, 
and is also excellent in resistance to the liquid for recording, e.g. ink, 
and is excellent in mechanical strength. Further it has an excellent 
characteristic as the constituent member of a liquid jet recording head 
that a precise and high resolution pattern can be formed by patterning 
with an active energy ray. Further, the resin composition can be used as a 
dry film, and also in that case, the above excellent characteristics can 
be exhibited. 
The composition of the active energy curing type resin composition to be 
used for formation of the recording head of the present invention will be 
described in detail below. 
The heat-crosslinkable linear copolymer (i) which is an essential component 
of the active energy ray-curing resin composition has 5 to 30 mol % of a 
monomer of the above formula I having hydrophilic property and 
heat-crosslinkability and 5 to 50 mol % of a monomer of the above formula 
II for imparting sufficient adhesiveness and mechanical strength to the 
pattern obtained by curing of the composition as the components for 
copolymerization, respectively. Excellent adhesiveness to a substrate can 
be exhibited due to the above hydrophilic property, and also excellent 
properties of structural materials such as heat resistance, chemical 
resistance, mechanical strength, etc. can be exhibited by heat 
crosslinkability. The monomers represented by the above formulae I and II 
should preferably be contained in the heat crosslinkable linear copolymer 
at a proportion of about 50 mol % or less as their total amount. 
Specific examples of the monomer represented by the formula I to be used in 
construction of the above heat crosslinkable linear copolymer may include 
acrylamide derivatives such as N-methylol(meth)acrylamide (hereinafter the 
expression (meth)acrylamide means includes both acrylamide and 
methacrylamide) N-propoxymethyl(meth)acrylamide, 
N-n-butoxymethyl(meth)acrylamide, 
.beta.-hydroxyethoxymethyl(meth)acrylamide, 
N-ethoxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, 
N-acetoxymethyl(meth)acrylamide, 
.alpha.-hydroxymethyl-N-methylolacrylamide, 
.alpha.-hydroxyethyl-N-butoxymethylacrylamide, 
.alpha.-hydroxypropyl-N-propoxymethylacrylamide, .alpha.-ethyl-N-methylol 
acrylamide, .alpha.-propyl-N-methylolacrylamide and the like. 
These monomers represented by the formula I are required to be contained at 
a proportion of 5 to 30 mol % in the heat crosslinkable linear copolymer. 
With a content less than 5 mol %, sufficient chemical resistance can not 
be imparted to the pattern obtained by curing of the resin composition for 
formation of the recording head of the present invention. On the other 
hand, if the content exceeds 30 mol %, there will ensue the problem such 
that the pattern obtained by curing becomes brittle. 
On the other hand, the monomer represented by the formula II is required to 
be contained at a proportion of 5 to 50 mol % in the heat crosslinkable 
linear copolymer. With a content less than 5 mol %, sufficient 
adhesiveness and mechanical strength can not be imparted to the pattern 
obtained by curing of the said resin composition of the present invention. 
On the contrary, if the content exceeds 50 mol %, the composition obtained 
will be markedly lowered in softening point, whereby there will ensue the 
problems such as lowering in surface hardness or deterioration in chemical 
resistance by swelling of the pattern obtained by curing of the 
composition. 
R.sup.4 in the monomer represented by the formula II used for formation of 
the heat crosslinkable copolymer can be any divalent hydrocarbon group 
which may have internally an ether bond and also may be substituted with 
halogen atoms. Preferable examples of R.sup.4 include alkylene group 
having 2 to 12 carbon atoms which may be substituted with halogen atoms, 
alicyclic hydrocarbon group such as 1,4-bismethylenecyclohexane, and 
hydrocarbon groups containing an aromatic ring such as 
bisphenyldimethylmethane. 
Specific examples of the monomer represented by the formula II include 
(.alpha.-alkyl)acrylic acid esters having one or more urethane bond in one 
molecule comprising reaction products obtained by the reaction of 
(.alpha.-alkyl)acrylic acid esters having one hydroxyl group in one 
molecule with monoisocyanate compounds. Examples of (meth)acrylic acid 
esters having at least one hydroxyl group in one molecule to be used in 
preparation of the monomer represented by the above formula II include 
2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 
3-chloro-2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 
3-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 
6-hydroxyhexyl (meth)acrylate or Light Ester HO-mpp (produced by Kyoeisha 
Yushi Kagaku Kogyo K.K.). As the (.alpha.-alkyl)acrylic acid ester having 
one hydroxyl group in one molecule, other than above, (a) esters of 
aliphatic or aromatic divalent alcohols with (meth)acrylic acids and (b) 
(meth)acrylic acid esters of monoepoxy compounds can be similarly used. 
Examples of the divalent alcohol to be used in the above (a) may include 
1,4-cyclohexanedimethanol, 1,10-decanediol, neopentylglycol, 
bis(2-hydroxyethyl)terephthalate, addition reaction products of 2 to 10 
mols of ethyleneoxide or propyleneoxide added to bis phenol A. On the 
other hand, the monoepoxy compounds to be used in the above (b) may 
include Eporite M-1230 (trade name, produced by Kyoeisha Yushi Kagaku 
Kogyo, K.K.), phenylglycidyl ether, cresylglycidyl ether, butylglycidyl 
ether, octylene oxide, n-butylphenol glycidyl ether, etc. 
As the monoisocyanate compound to be used in preparation of the monomer 
represented by the formula II, there may be included alkyl monoisocyanates 
comprising one isocyanate group added to alkyl groups $ having 3 to 12 
carbon atoms and phenyl isocyanate, cresyl monoisocyanate and the like. 
These monomers represented by the formula II can prepared easily by 
carrying out the reaction between an acrylic acid ester having one 
hydroxyl group in one molecule and a monoisocyanate compound in the 
presence of a catalyst such as dibutyl tin dilaurate. 
The monomer represented by the formula I to be used for preparing the 
heat-crosslinkable linear copolymer has hydrophilic property and imparts 
firm adhesiveness to the composition of the present invention when the 
resin composition used in the present invention adheres to a substrate 
such as glass, ceramics, plastic, etc. The monomer represented by the 
above formula I also has condensing crosslinkability by heating and will 
generally form crosslinks through elimination of water molecules or 
alcohol at a temperature of 100 .degree. C. or higher to thereby form a 
network structure in the heat crosslinkable copolymer itself after curing, 
whereby excellent chemical resistance and mechanical strength can be 
imparted to the pattern obtained by curing. 
As the heat-crosslinkable linear copolymer, in addition to the monomers 
represented by the above formulae I and II, various monomers generally 
used for the preparation of acrylic resins, vinyl resins, etc., can be 
used as the components for copolymerization in amounts within the range of 
from 20 to 90 mol %. These monomers can be used for various purposes such 
as imparting high agglomeration strength to the resin composition for 
formation of a resin cured film in the present invention, etc. 
The resin composition used for formation of the recording head of the 
present invention can be provided in various forms such as a solution or a 
solid film, etc. If it is to be used as a dry film, in order to maintain 
the composition in the form of a film, it is preferable to use a 
heat-crosslinkable linear copolymer obtained by copolymerization of a 
monomer giving relatively rigid properties having a glass transition 
temperature of about 50 .degree. C. or higher in addition to the monomers 
of the formulae I and II. Examples of the monomer other than those of the 
formulae I and II to be used in preparation of a heat-crosslinkable linear 
copolymer suitable for such a purpose may include alkyl methacrylates 
having 1 to 4 carbon atoms in the alkyl group such as methyl methacrylate, 
ethyl methacrylate, isobutyl methacrylate, t-butyl methacrylate and the 
like, acrylonitrile, isobornyl methacrylate, isobornyl acrylate, styrene, 
etc., of which homopolymers have a glass transition temperature of about 
50 .degree. C. or higher. Of course, these monomers can be used by 
selecting suitably at least one of them. Further, in addition to these 
monomers, other known monomers having hydroxy group, amino group, carboxyl 
group or glycidyl group or monomers of which polymers have a glass 
transition temperature lower than about 50 .degree. C. may be suitably 
selected and used. 
The above hydroxyl containing monomer may be exemplified by 2-hydroxyethyl 
(meth)acrylate, 3-chloro-2-hydroxy (meth)acrylate and the like, and the 
amino containing monomer such as N,N-dimethylaminoethyl (meth)acrylate, 
(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, 
N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, 
N,N-di-tbutylaminoethyl(meth) acrylamide and the like. Examples of the 
carboxyl containing monomer may include (meth)acrylic acid, fumaric acid, 
itaconic acid or those known under the trade names Aronix M-5400, Aronix 
M5500, etc., which are products of Toa Gosei Kagaku K.K., and the monomer 
having glycidyl group may include glycidyl (meth)acrylate, etc. 
On the other hand, when the resin composition for formation of a resin 
cured film in the present invention is to be used in a solution form, it 
is also possible to employ heat-crosslinkable linear copolymer having a 
low glass transition temperature which can give flexibility to the 
composition. However, also in this case, in order to obtain a pattern 
having excellent chemical resistance and high mechanical strength, it is 
preferable to use a heat-crosslinkable linear copolymer having a high 
glass transition temperature. 
Anyway, the heat-crosslinkable linear copolymer to be used for the resin 
composition for formation of a resin cured film in the present invention 
enables precise patterning by imparting form retentivity to the 
composition in the curing step of the composition (namely formation of a 
pattern by irradiation of active energy ray and subsequent heat curing), 
and also gives excellent adhesiveness, chemical resistance and high 
mechanical strength to the pattern obtained by curing. 
The monomer (ii) having an ethylenically unsaturated bond to be used as 
another component in the resin composition for formation of a resin cured 
film in the present invention is a component for permitting the said 
composition to exhibit curability with an active energy ray, preferably 
having a boiling point of 100 .degree. C. or higher under atmospheric 
pressure, preferably also having two or more ethylenically unsaturated 
bonds, and various known monomers curable by irradiation of an active 
energy ray can be used. 
Specific examples of such monomers having two or more ethylenically 
unsaturated bonds include (a) acrylic acid esters or methacrylic acid 
esters of polyfunctional epoxy resins having two or more epoxy groups in 
one molecule, (b) acrylic acid esters or methacrylic acid esters of 
alkyleneoxide addition products of polyhydric alcohols, (c) polyester 
acrylates having acrylic acid ester group at the terminal ends of the 
molecular chains of polyesters having molecular weights of 500 to 3000 
comprising dibasic acid and dihydric alcohol, (d) the reaction products 
between polyisocyanates and acrylic acid monomers having hydroxyl groups. 
The above monomers (a)-(d) may be urethane modified products having 
urethane bonds in the molecules. 
Examples of the monomers belonging to (a) include acrylic acid or 
methacrylic acid esters of epoxy resins as represented by the bisphenol A 
type, novolac type, alicyclic type, or polyfunctional epoxy resins such as 
bisphenol S, bisphenol F, tetrahydroxyphenylmethane tetraglycidyl ether, 
resorcinol diglycidyl ether, glycerine triglycidyl ether, pentaerythritol 
triglycidyl ether, isocyanuric acid triglycidyl ether and epoxyurethane 
resins represented by the following formula III: 
##STR4## 
(wherein R represents an alkylene group or an oxyalkylene group, R.sub.0 
represents 
##STR5## 
or an alkylene group). 
Examples of the monomers belonging to include ethyleneglycol 
di(meth)acrylate, diethyleneglycol di(meth) acrylate, polyethyleneglycol 
di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethyleneglycol 
di(meth)acrylate, pentaerythritol tri(meth)acrylate and the like, and 
those known under the trade names of KAYARAD HX-220, HX-620, D-310, D-320, 
D-330, DPHA, R-604, DPCA-20, DPCA-30, DPCA-60, DPCA-120 (all produced by 
Nippon Kayaku K.K.), and also those known under the trade names of NK 
ester BPE-200, BPE-500, BPE-1300, A-BPE-4 (all produced by Shin Nakamura 
Kagaku K.K.), etc., may also be used. 
The monomers belonging to may be exemplified by those known under the trade 
names of Aronix M-6100, M-6200, M-6250, M-6300, M-6400, M-7100, M-8030, 
M-8060, M-8100 (all produced by Toa Gosei Kagaku K.K.). Examples of the 
monomers belonging to and having urethane bonds of polyester include those 
known under the trade names of Aronix M-1100, Aronix M-1200, (both 
produced by Toa Gosei Kagaku K.K.). 
The monomers belonging to (c) may include the reaction products between 
polyisocyanate such as tolylene diisocyanate, isophorone diisocyanate, 
hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine 
diisocyanate, diphenylmethane diisocyanate or the like and a hydroxyl 
containing acrylic monomer, and it is possible to use the reaction 
products having (meth)acrylic acid esters containing hydroxyl group(s) 
added to polyisocyanate compounds known under the trade names of Sumidule 
N (buret derivative of hexamethylene diisocyanate), Sumidule L 
(trimethylolpropane modified product of tolylene diisocyanate) (all 
produced by Sumitomo Bayer Urethane K.K.), etc. The hydroxyl containing 
acrylic monomer as herein mentioned may include typically (meth)acrylic 
acid esters, preferably, hydroxyethyl (meth)acrylate, hydroxypropyl 
(meth)acrylate. It is also possible to use other acrylic monomers 
containing hydroxyl group(s) previously mentioned for preparation of the 
monomer represented by the formula I in the heat-crosslinkable linear 
copolymer. 
In addition to the monomers having two or more ethylenically unsaturated 
bonds as mentioned above, it is also possible to use monomers having only 
one ethylenically unsaturated bond as mentioned below together with those 
monomers. To exemplify such monomers having one ethylenically unsaturated 
bond, there may be included, for example, carboxyl containing unsaturated 
monomers such as acrylic acid, methacrylic acid or the like; glycidyl 
containing unsaturated monomers such as glycidyl acrylate, glycidyl 
methacrylate or the like; C.sub.2 -C.sub.8 hydroxyalkyl esters of acrylic 
acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl 
methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate or the 
like; monoesters of acrylic acid or methacrylic acid with 
polyethyleneglycol or polypropyleneglycol such as polyethyleneglycol 
monoacrylate, polyethyleneglycol monomethacrylate, polypropyleneglycol 
monoacryllate, polypropyleneglycol monomethacrylate or the like; C.sub.1 
-C.sub.12 alkyl or cycloalkyl esters of acrylic acid or methacrylic acid 
such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl 
acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, 
cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl 
methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl 
methacrylate, octyl methacrylate, lauryl methacrylate, cyclohexyl 
methacrylate or the like; other monomers such as styrene, vinyltoluene, 
methylstyrene, vinyl acetate, vinyl chloride, vinyl isobutyl ether, 
acrylonitrile, acrylamide, methacrylamide, acrylic acid or methacrylic 
acid adduct of alkylglycidyl ether, vinylpyrrolidone, 
dicyclopentenyloxyethyl(meth)acrylate, .epsilon.-caploractone-modified 
hydroxyalkyl(meth)acrylate, tetrahydrofurfulyl acrylate, phenoxyethyl 
acrylate; and others. 
Anyway, by use of the above monomer having ethylenically unsaturated bonds, 
curability to an active energy ray can be imparted to the resin 
composition for formation of a resin cured film in the present invention. 
The active energy ray-curing resin composition for formation of a resin 
cured film in the present invention should preferably contain a 
photopolymerization initiator added therein when employing an active 
energy ray with wavelength of 250 nm to 450 nm. As the photopolymerization 
initiator, known substances to be used in photopolymerization can be used 
without any particular limitation. 
Specific examples of such photopolymerization initiators include benzyl; 
benzoin alkyl ethers such as benzoin isobutyl ether, benzoin isopropyl 
ether, benzoin-n-butyl ether, benzoin ethyl ether, benzoin methyl ether 
and the like; benzophenones such as benzophenone, 
4,4'-bis(N,N-diethylamino)benzophenone, benzophenone methyl ether and the 
like; anthraquinones such as 2-ethylanthraquinone, 2-t-butylanthraquinone 
and the like; xanthones such as 2,4-dimethylthioxanthone, 
2,4-diisopropylthioxanthone and the like; acetophenones such as 
2,2-dimethoxy-2-phenylacetophenone, 
.alpha.,.alpha.-dichloro-4-phenoxyacetophenone, 
p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, 
2,2-diethoxyacetophenone, p-dimethylaminoacetophenone and the like; or 
hydroxycyclohexylphenyl ketone (e.g. Irugacure 184, produced by Ciba Geigy 
Co.), 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one (e.g. Darocure 
1116, produced by MERCK Co.), 2-hydroxy-2-methyl-1-phenyl-propane-1-one 
(Darocure 1173, produced by MERCK Co.); etc., as preferable ones. In 
addition to these photopolymerization initiators, amino compounds may be 
added as the photopolymerization accelerator. 
The amino compounds to be used as the photopolymerization accelerator may 
include ethanolamine, ethyl-4-dimethylaminobenzoate, 
2-(dimethylamino)ethylbenzoate, p-dimethylamino benzoic acid n-amylester, 
p-dimethylaminobenzoic acid isoamylester, etc. 
The constitutional ratio of the above materials constituting the active 
energy ray-curing resin composition for formation of a resin cured film in 
the present invention may be made 20 to 80 wt. %, preferably 20 to 50 wt. 
% for the heat crosslinkable linear copolymer and 80 to 20 wt. %, 
preferably 50 to 80 wt. % for the monomer having ethylenically unsaturated 
bonds. 
When a photopolymerization initiator is used in the resin composition of 
the present invention, the photopolymerization initiator may be used in an 
amount within the range from 0.1 to 20 parts by weight, preferably from 1 
to 10 parts by weight based on 100 parts by weight of the resin components 
comprising the heat-crosslinkable linear copolymer and the monomer having 
ethylenically unsaturated bonds. 
As the solvent to be used when employing the active energy ray-curing resin 
composition for formation of a resin cured film in the present invention 
in the form of a solution or when coating the composition on a plastic 
film which is a film substrate in formation of a dry film, hydrophilic 
solvents such as alcohols, glycol ethers, glycol esters, etc., may be 
employed. Of course, it is also possible to use mixtures comprising these 
hydrophilic solvents as the main component, mixed optionally at 
appropriate proportions with ketones such as methyl ethyl ketone, methyl 
isobutyl ketone, etc., esters such as ethyl acetate, isobutyl acetate, 
etc., aromatic hydrocarbons such as toluene, xylene, etc., and their 
halogen derivatives, aliphatic solvents containing chlorine such as 
methylene chloride, 1,1,1-trichloroethane, etc. These solvents can also be 
used as the developer for the resin composition after pattern exposure. 
The active energy ray-curing resin composition for formation of a resin 
cured film in the present invention may further contain in addition to the 
above photopolymerization initiator or the solvent as described above, 
additives such as catalysts for condensation crosslinking, heat 
polymerization inhibitors, colorants (dyes and pigments), fine particulate 
fillers, adhesion promotors, plasticizers, etc., if desired. 
The condensation crosslinking catalyst may include sulfonic acids, 
typically p-toluenesulfonic acid, carboxylic acids such as formic acid, 
etc. The heat polymerization inhibitor may include hydroquinone and 
derivatives thereof, p-methoxyphenol, phenothiazine, etc. As the colorant 
there can be added oil-soluble dyes and pigments within the range which do 
not substantially prevent transmission of the active energy ray. As the 
filter, for enhancement of hardness of coating, as well as for enhancement 
of coloration, adhesion, mechanical strength, there may be employed 
extender pigments, plastic fine particles, etc., which are used in coating 
materials in general. As the adhesion promotor, silane coupling agents, 
low molecular weight surfactants as inorganic surface modifiers may be 
effectively used in the composition of the present invention. 
The resin composition comprising the composition as described above is 
cured with an active energy ray to form the resin cured film 3H possessed 
by the recording head of the present invention. Next, as an embodiment of 
the case when employing a dry film type as the resin composition for 
formation of the resin cured film 3H, the method for preparing the liquid 
jet recording head of the present invention is described in detail by 
referring to the drawings. 
FIGS. 2 to 6 are schematic illustrations for description of the preparation 
procedure of the liquid jet recording head of the present invention. 
For formation of the liquid jet recording head of the present invention, 
first, as shown in FIG. 2, a discharge energy generating element 2 such as 
heat generating element or piezoelectric element is arranged in a desired 
number on a substrate 1 such as glass, ceramic, plastic or a metal. If 
desired, for the purpose of imparting resistance to the liquid for 
recording or electrical insulating property, etc., to the surface of the 
substrate 1, the surface may be coated with a protective layer of 
SiO.sub.2, Ta.sub.2 O.sub.5, glass, etc. Also, to the discharge energy 
generating element 2 is connected electrodes for inputting recording 
signals, although not shown in the drawing. 
Next, the surface of the substrate 1 obtained after the step shown in FIG. 
2 is cleaned and at the same time dried at, for example, 80.degree. to 150 
.degree. C., and then the active energy ray-curing resin composition 3 as 
described above of the dry film type (film thickness, about 25 .mu.m to 
100 .mu.m), as shown in FIG. 3A and FIG. 3B is heated to about 40.degree. 
to 150 .degree. C. and laminated on the substrate surface 1A at a speed 
of, for example, 0.5 to 0.4 f/min. under the pressurizing condition of 1 
to 3 Kg/cm.sup.2. 
Subsequently, as shown in FIG. 4, on the dry film layer 3 provided on the 
substrate surface 1A, a photomask 4 having a pattern 4P with a desired 
shape which does not transmit the active energy ray is superposed, and 
then exposure is effected from above the photomask 4. 
Registration between the photomask 4 and the substrate 1 is effected so 
that the above element 2 may be positioned in the liquid passage region 
finally formed after the steps of exposure and developing processing, 
etc., for example, according to the method in which registration marks are 
previously drawn respectively on the substrate 1 and the mask 4 and 
registration is effected following the marks. 
By carrying out such an exposure, the portion other than that covered with 
the pattern, namely the portion exposed of the dry film layer 3 is cured 
by polymerization, to become insoluble in a solvent, while the unexposed 
portion remains soluble in a solvent. 
The active energy ray to be used for such a pattern exposure may include 
ultraviolet rays (UV-rays) or electron beams which have widely been 
practically applied. As the UV-ray light source, there may be employed 
high pressure mercury lamps, ultra-high pressure mercury lamps, metal 
halide lamps, etc., enriched in light with wavelength of 250 nm to 450 nm, 
preferably those which can give a light intensity of about 1 mW/cm.sup.2 
to 100 mW/cm.sup.2 at the wavelength in the vicinity of 365 nm at a 
distance between the lamp and the material to be irradiated which is 
practically permissible. The electron beam irradiation device is not 
particularly limited, but a device having a dose within the range of 0.5 
to 20 M Rad is practically suitable. 
After completion of the pattern exposure of the dry film layer 3, the dry 
film 3 subjected to exposure is developed by, for example, dipping in a 
volatile organic solvent such as 1,1,1-trichloroethane, etc., to remove by 
dissolution the unpolymerized (uncured) portion of the dry film layer 3 
which is solvent soluble, thereby forming the grooves which will finally 
become the liquid passages 6-2 and liquid chamber 6-1 with the resin cured 
film 3H remaining on the substrate 1 as shown in FIG. 5A and FIG. 5B. 
As the next step, the cured resin film 3H on the substrate 1 is subjected 
to heat polymerization by heating, for example, at 100 .degree. C. for 
further about 5-10 min. 
In the recording head of this embodiment, the grooves for liquid passages 
6-2 and liquid chamber 6-1 are formed by referring to an example using a 
resin composition of the dry film type, namely a solid composition. 
However, the active energy ray-curing resin composition which can be used 
in formation of the recording head of the present invention is not limited 
to only solid compositions, but also a liquid composition may be 
available. 
As the method for forming a layer comprising the composition by use of a 
liquid resin composition on the substrate, there may be employed, for 
example, the method according to squeegee as used in preparation of a 
relief image, namely the method in which a wall with a height 
corresponding to the desired thickness of the resin composition layer to 
be formed is provided around the substrate and superfluous resin 
composition is removed by means of a squeegee, etc. In this case, the 
resin composition may appropriately have a viscosity of 100 cp to 3000 cp. 
The height of the wall placed around the substrate is also required to be 
determined in view of the amount reduced by evaporation of the solvent 
contained in the light-sensitive resin composition. 
When a solid resin composition is employed, it is suitable to use the 
method in which a dry film is plastered on the substrate by pressure 
contact under heating. 
However, in forming the recording head of the present invention, a solid 
film type is convenient in handling and also with respect to easy and 
correct control of the thickness. 
After having thus formed the grooves for constituting finally the liquid 
passages 6-2 and the liquid chamber 6-1 with the resin cured film 3H, a 
flat plate 7 which is a covering over the grooves is bonded with an 
adhesive on the resin cured film 3H to form a bonded body, as shown in 
FIG. 6A and FIG. 6B. 
In the steps shown in FIG. 6A and FIG. 6B, as the specific method for 
providing the covering 7, for example, after the flat plate 7 of glass, 
ceramic, metal, plastic, etc., is applied with an epoxy resin type 
adhesive by spin coating to a thickness of 3 to 4 .mu.m, the adhesive 
layer is previously heated to effect the so called B-staging and then 
plastered on the cured dry film 3H, followed by main curing of the above 
adhesive layer. However, it is also possible to use no adhesive such as by 
having a flat plate 7 of a thermoplastic resin such as acrylic resin, ABS 
resin, polyethylene, etc., thermally fused directly onto the resin cured 
film 3H. 
It is also preferable to use the method in which a resin layer comprising 
the resin composition for formation of the resin cured film in the present 
invention is provided on the covering 7 on the side to be bonded to the 
liquid passages, the resin layer is thermally fused to the resin cured 
film 3H having formed liquid passages thereon and thereafter heated with 
irradiation of an active energy ray, namely the method of using the resin 
composition for formation of the resin cured film in the present invention 
as the adhesive. 
In FIG. 6, 6-1 shows a liquid chamber, 6-2 liquid passages and 8 the 
thru-holes for connecting feeding pipes (not shown) for feeding the liquid 
for recording to the liquid chamber 6-1 from outside of the recording head 
not shown. 
After having completed thus the bonding between the resin cured film 3H 
provided on the substrate 1 and the flat plate 7, the bonded body is cut 
along C--C' positioned on the downstream side of the liquid passage 6-2 
shown in FIG. 6A and FIG. 6B, thereby forming an orifice for discharging 
the liquid for recording which is the opening portion of the liquid 
passage at the cut surface. 
This step is conducted for making the interval between the discharge energy 
generating element 2 and the orifice 9 adequate, and the region to be cut 
may be selected suitably. For this cutting, there may be employed the 
dicing method, etc., which is conventionally employed in semiconductor 
industries. 
The downstream portion of the liquid passage as mentioned in the present 
invention refers to the region on the downstream side in the flow 
direction of the liquid for recording when recording is performed by use 
of a recording head, more specifically the portion of the liquid passage 
downstream of the position where the discharge energy generating element 2 
is located. 
After completion of cutting, the cut surface is smoothened by polishing and 
a feeding pipe 10 is mounted on the thru-hole 8 to complete a liquid jet 
recording head as shown in FIG. 1. 
In the recording head as described above, the liquid passages 6-2 and the 
liquid chamber 6-1 are formed integrally with a resin cured film 3H, but 
the recording head of the present invention is not limited to such a 
structure, and it is also possible to use a structure in which liquid 
passages are formed separately from the liquid chamber. However, even if 
any structure may be taken, the recording head of the present invention is 
such that at least a part of the resin for forming the liquid passage is 
formed by use of the active energy ray-curing resin composition as 
described above. 
The liquid jet recording head of the present invention uses, as the active 
energy ray-curing resin composition which is the constitutional member of 
said head, a composition having very excellent sensitivity to the active 
energy ray and resolution as the pattern forming material which are 
imparted primarily by the monomer having ethylenically unsaturated bonds 
contained as the essential component in said composition, and it has been 
rendered possible to obtain a liquid jet recording head excellent in 
dimensional precision with good yield by use of said resin composition. 
Also, the resin composition to be used in the present invention has 
excellent adhesion to a substrate, mechanical strength and chemical 
resistance imparted primarily by the heat-crosslinkable linear polymer as 
the essential component, whereby it has been also rendered possible to 
obtain a recording head having durability for a long term by use of said 
composition. 
Further, the recording head of the present invention comprises a substrate 
and a resin cured film layer for forming grooves which become at least 
liquid passages and is excellent in durability of the respective members 
constituting the recording head as well as adhesiveness between the 
respective members, with the resin cured film being also minutely worked 
with good precision, thus having excellent recording characteristics, high 
reliability and also excellent durability during usage. 
The present invention is described in more detail by referring to the 
following Synthetic examples and Examples. 
Synthetic example 
By solution polymerization of methyl methacrylate, N-methylol acrylamide 
and Nissocure UM-1M.sup.*1 in methylcellosolve (methyl 
methacrylate/N-methylol acrylamide/ Nissocure UM-1M=50/25/25 moler ratio), 
a linear polymer having heat crosslinkability with a weight average 
molecular weight of 5.7.times.10.sup.4 was obtained (this is called P-1). 
*1: Product name of Shin Nisso Kako K.K., which is a monomer having the 
structure shown below: 
##STR6## 
By use of the linear polymer P-1, an active energy ray curing type resin 
composition was prepared as follows. 
______________________________________ 
P-1 100 parts by weight 
Light Ester 3002M*.sup.2 
90 parts by weight 
Pentaerythritol triacrylate 
60 parts by weight 
Benzophenone 9 parts by weight 
Micheler's ketone 3 parts by weight 
Paratoluene sulfonic acid 
2.5 parts by weight 
Crystal Violet 0.5 parts by weight 
Methyl cellosolve 250 parts by weight 
______________________________________ 
*.sup.2 Methacrylic acid ester of epoxy resin produced by Kyoeisha Yushi 
Kagaku Kogyo K.K. 
Next, the above resin composition was applied to a polyethylene 
terephthalate film with a thickness of 16 .mu.m by a wire bar, followed by 
drying at 100 .degree. C. for 20 minutes, to prepare a dry film according 
to the present invention having a resin composition layer with a film 
thickness of 75 .mu.m. 
EXAMPLE 
By use of the dry film prepared in the Synthetic example, following the 
steps of FIG. 1 to FIG. 6 as described previously in the specification, an 
on-demand type liquid jet recording head having an orifice having 10 
orifices (orifice dimension: 75 .mu.m.times.50 .mu.m, pitch 0.125 mm) with 
heat generating elements [hafnium boride (HfB.sub.2)] as the discharge 
energy generating element was prepared as follows. Thirth recording heads 
were was prepared in the same shape. 
First, a plurality of heat generating elements were arranged at the 
predetermined positions on the substrate comprising silicon and electrodes 
for applying recording signals were connected to these. 
Next, a SiO.sub.2 layer (thickness 1.0 .mu.m) as the protective film was 
provided on the substrate surface having the heat generating elements 
arranged thereon, and the surface of the protective layer was cleaned and 
dried. Then, the dry film with a thickness of 75 .mu.m as shown in the 
above Synthetic example heated to 80.degree. C. was laminated on the 
protective layer at a speed of 0.4 f/min. under the pressurizing condition 
of 1 Kg/cm.sup.2. 
Subsequently, on the dry film provided on the substrate surface, a 
photomask having a pattern corresponding to the shapes of liquid passages 
and liquid chamber was superposed and, after performing registration so 
that the above element may be provided in the liquid passages finally 
formed, the dry film was exposed to UV-ray with an intensity of 12 
mW/cm.sup.2 from above the photomask for 30 seconds. 
Next, the dry film exposed was developed by dipping in 
1,1,1-trichloroethane to remove by dissolution the unpolymerized (uncured) 
portion of the dry film from the substrate, thereby forming grooves which 
will become finally the liquid passages and liquid chamber with the cured 
dry film remaining on the substrate. 
After completion of development, the cured dry film on the substrate was 
heated at 150 .degree. C. for one hour, followed further by irradiation of 
UV-ray with an intensity of 50 mW/cm.sup.2 for 2 minutes to further cure 
the film. 
After having formed thus the grooves for the liquid passages and liquid 
chamber with the cured dry film, a flat plate comprising soda glass 
provided with a thru-hole which becomes the covering over the groove 
formed was coated with an epoxy type resin adhesive in the thickness of 3 
.mu.m by spin coating, then preheated to effect B-staging and plastered on 
the cured dry film, followed further by main curing of the adhesive to 
effect adhesion fixing, thus forming a bonded body. 
Subsequently, on the downstream side of the liquid passage of the bonded 
body, namely at the position of 0.150 mm toward the downstream side from 
the position where the discharge energy generating element is located, the 
bonded body was cut vertically relative to the liquid passage by means of 
a commercially available dicing saw (trade name: DAD 2H/6 model, produced 
by DISCO Co.) to form orifices for discharging the liquid for recording. 
Finally, the cut surfaces were washed and dried, further smoothened by 
polishing of the cut surfaces, and feeding pipes for feeding the liquid 
for recording were fitted to the thru-holes to complete the liquid jet 
recording head. Every one of the recording heads obtained was found to be 
excellent in dimensional precision having liquid passages and liquid 
chambers which have faithfully reproduced the mask pattern. The orifice 
dimension was 50.+-.5 .mu.m and a orifice pitch 125.+-.5 .mu.m. 
The recording heads thus prepared were tested for quality and durability 
during prolonged use, as shown below. 
First, for the recording heads obtained, durability test was conducted by 
dipping in the liquids for recording having the following respective 
compositions at 60.degree. C. for 1000 hours (the environmental conditions 
comparable to prolonged use of a recording head). 
______________________________________ 
Liquid components for recording 
______________________________________ 
(1) H.sub.2 O/ethyleneglycol/polyethyleneglycol #200/C.I. 
pH = 8.0 
Direct Black 154*.sup.1 
(= 60/30/5/5 weight parts) 
(2) H.sub.2 O/ethyleneglycol/C.I. Direct Black 154 
pH = 9.0 
(= 55/40/5 weight parts) 
(3) H.sub.2 O/diethyleneglycol/N--methyl-2-pyrrolidone/ 
pH = 7.0 
C.I. Direct Black 154 
(= 55/30/10/5 weight parts) 
(4) H.sub.2 O/diethyleneglycol/1,3-dimethyl-2- 
pH = 10.0 
imidazolidinone/C.I. Direct Blue 86*.sup.2 
(= 57/30/10/3 weight parts) 
______________________________________ 
(Note) 
*.sup.1 to *.sup.2 are watersoluble dyes, and caustic soda was employed 
for adjustment of pH. 
For each liquid for recording, five recording heads were provided 
respectively for the durability test. 
After the durability test, each head subjected to said test was observed 
about the bonded state between substrate and the covering and the dry 
film. As the result, no peel-off or damage could be recognized in all of 
the recording heads, but good adhesiveness was exhibited. 
Next, separately for the 10 recording heads obtained, each head was mounted 
on a recording device, and the printing test was practiced by use of the 
above liquid for recording by applying recording signals of 10.sup.8 pulse 
continuously to the recording head for 14 hours. For each recording head, 
immediately after initiation of printing and after elapse of 14 hours, 
substantially no lowering in performance in both of the discharging 
performance of the liquid for recording and printed state can be 
recognized. Thus, the recording head was found to be excellent in 
durability. 
COMATIVE EXAMPLE 
Recording heads were prepared in the same manner as in the Example except 
for using a commercially available dry film Vacrel with a thickness of 75 
.mu.m (trade name of dry film solder mask, produced by Du Pont de Nemours 
Co.) and a commercially available dry film Photec SR-3000 with a film 
thickness of 50 .mu.m (trade name, produced by Hitachi Kasei Kogyo K.K.). 
For these recording heads, the same durability test as in the Example was 
practiced. 
In the course of durability test, when employing Vacrel as the dry film, 
peel-off was recognized after 100 hours with the liquids for recording (2) 
and (4). Also, after 300 hours, peel-off was recognized with the liquids 
for recording (1) and (3). 
On the other hand, when employing Photec SR-3000 as the dry film, peel-off 
was recognized after 300 hours with a respective liquids for recording of 
(1) to (4).