U.S. patent application number 11/390305 was filed with the patent office on 2006-10-26 for die apparatus, method for producing perforated work plate, perforated work plate, liquid-jet head and liquid-jet apparatus.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Koichi Saito, Narimitsu Saito, Nagamitsu Takashima, Shinichi Tonami, Ryoji Uesugi.
Application Number | 20060236536 11/390305 |
Document ID | / |
Family ID | 37185337 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060236536 |
Kind Code |
A1 |
Saito; Koichi ; et
al. |
October 26, 2006 |
Die apparatus, method for producing perforated work plate,
perforated work plate, liquid-jet head and liquid-jet apparatus
Abstract
A die apparatus is composed of a lower receiving die, a round
punch having the shape of a fine hole, and PET provided between the
lower receiving die and the round punch. The round punch is passed
through a work plate placed on the PET to cause a punched-out piece
to remain within the PET, thereby boring the fine hole. The work
plate having such fine holes is thus easily prepared, and applied
as a filter for a liquid-jet head.
Inventors: |
Saito; Koichi; (Nagano-ken,
JP) ; Saito; Narimitsu; (Yamagata-ken, JP) ;
Tonami; Shinichi; (Yamagata-ken, JP) ; Takashima;
Nagamitsu; (Nagano-ken, JP) ; Uesugi; Ryoji;
(Nagano-ken, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SEIKO EPSON CORPORATION
|
Family ID: |
37185337 |
Appl. No.: |
11/390305 |
Filed: |
March 28, 2006 |
Current U.S.
Class: |
29/890.1 |
Current CPC
Class: |
B21D 53/76 20130101;
Y10T 29/49401 20150115 |
Class at
Publication: |
029/890.1 |
International
Class: |
B21D 53/76 20060101
B21D053/76 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2005 |
JP |
2005-092286 |
Mar 30, 2005 |
JP |
2005-096909 |
Claims
1. A die apparatus for boring a through-hole in a work plate,
comprising a lower receiving die, a punch, and a flexible member
provided between the lower receiving die and the punch, and wherein
the punch is passed through the work plate placed on the flexible
member to press a punched-out piece into an interior of the
flexible member, thereby boring the through-hole in the work
plate.
2. The die apparatus according to claim 1, wherein the flexible
member is a polymer material.
3. The die apparatus according to claim 1, wherein a thickness of
the flexible member is twice or more a thickness of the work
plate.
4. The die apparatus according to claim 1, wherein a surface of the
lower receiving die facing the flexible member is flat.
5. A method for producing a perforated work plate by use of a punch
and a lower receiving die, comprising passing the punch through the
work plate placed on a flexible member to press a punched-out piece
into an interior of the flexible member, thereby boring a
through-hole in the work plate.
6. The method for producing a perforated work plate according to
claim 5, wherein a surface of the lower receiving die facing the
flexible member is flat.
7. The method for producing a perforated work plate according to
claim 5, wherein the punched-out piece pressed into the interior of
the flexible member is allowed to remain in the interior of the
flexible member when the punch is pulled out of the flexible
member.
8. A perforated work plate formed by the method for producing a
perforated work plate according to claim 5.
9. A perforated work plate formed by the method for producing a
perforated work plate according to claim 6.
10. A perforated work plate formed by the method for producing a
perforated work plate according to claim 7.
11. A liquid-jet head having a pressure generating chamber and a
nozzle orifice, and including the perforated work plate according
to claim 8 for use in a filter for the liquid-jet head which traps
foreign matter contained in a liquid to be supplied to the pressure
generating chamber.
12. The liquid-jet head according to claim 11, wherein the filter
for the liquid-jet head is a filter sheet consisting of a metal
film alone, has a plurality of the through-holes formed in the
filter, and has irregularity lines formed on a surface of the
filter, the irregularity lines extending in a lattice pattern.
13. The liquid-jet head according to claim 12, wherein a size of
the through-hole of the filter is a size of the nozzle orifice or
smaller.
14. A liquid-jet apparatus including the liquid-jet head according
to claim 12.
15. A liquid-jet apparatus including the liquid-jet head according
to claim 13.
Description
[0001] The entire disclosure of Japanese Patent Application Nos.
2005-092286 filed Mar. 28, 2005 and 2005-096909 filed Mar. 30, 2005
is expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a die apparatus for boring fine
holes, which are through-holes, in an ultrathin plate as a work
plate. The die apparatus is preferred for application to the
preparation of a filter for a liquid-jet head for trapping foreign
matter contained in a liquid to be supplied to a pressure
generating chamber of the liquid-jet head.
[0004] The present invention also relates to a method for producing
a perforated work plate having fine holes, which are through-holes,
bored in an ultrathin plate as a work plate. This method is
preferred for application to the production of a perforated
ultrathin plate for use as a filter for a liquid-jet head for
trapping foreign matter contained in a liquid to be supplied to a
pressure generating chamber of the liquid-jet head.
[0005] The present invention also relates to a perforated work
plate having fine holes, which are through-holes, bored in an
ultrathin plate. This perforated work plate is preferred for
application to a filter for a liquid-jet head for trapping foreign
matter contained in a liquid to be supplied to a pressure
generating chamber of the liquid-jet head.
[0006] The present invention further relates to a liquid-jet head
including a filter having fine holes, which are through-holes,
bored in an ultrathin plate, the filter being used as a filter for
a liquid-jet head, and a liquid-jet apparatus including the
liquid-jet head.
[0007] 2. Description of the Related Art
[0008] Liquid-jet apparatuses are designed to jet various liquids,
and an ink-jet recording apparatus, in particular, is used widely.
The ink-jet recording apparatus has an ink-jet head for ejecting
ink droplets, which are liquids, through a plurality of nozzle
orifices. By the action of the ink-jet head, ink droplets are
caused to impinge on the surface of a recording sheet or the like,
which is a medium, thereby printing images or characters
thereon.
[0009] In the ink supply passage provided in the ink-jet head, a
flat plate-shaped filter is disposed for removing foreign matter
intruding into ink, namely, fine pieces of synthetic resin or air
bubbles remaining within the supply passage for some unknown cause.
As such a filter, a twilled filter or a nonwoven fabric filter is
usually adopted (see Japanese Patent Application Laid-Open No.
1999-10904).
[0010] However, the twilled filter has a low opening rate and
involves a great pressure loss (passage resistance), so that it has
been customary practice to increase the area of the filter. This
practice, however, increases the size of the filter, making it
difficult to downsize the ink-jet head. Moreover, the shape of the
passage within the filter is so complicated that the pressure loss
varies with each filter. Accommodating such variations within the
tolerance range is difficult, thereby destabilizing the ability to
trap foreign matter. Furthermore, the edge portion of the filter is
frayed, thus causing a tendency toward damage to components, for
example, during the step of assembling the filter. This poses
difficulty in handling of the filter, and brings disadvantage to
costs. With the nonwoven fabric, fine pieces of fiber are likely to
flow downward together with ink from the filter, deteriorating
reliability.
[0011] Under these circumstances, it has been contemplated to use a
filter having many fine holes (for example, holes of 15 .mu.m in
diameter) formed in an ultrathin metal plate (for example, SUS
plate of 10 to 20 .mu.m in thickness) by punching. By using as the
filter such an ultrathin metal plate having many fine holes formed
therein, it becomes possible to decrease the pressure loss, ensure
an adequate flow rate of ink, and impart a stable function of
trapping foreign matter.
[0012] In preparing the ultrathin metal plate having many fine
holes formed therein, it is conceivable to use a die apparatus
comprising an upper die (punch) having the same diameter as that of
the fine hole, and a lower die (die) having a depression (for
example, a hole having a diameter of 16 to 17 .mu.m) slightly
larger in diameter than the fine hole, and pass the punch through
the ultrathin metal plate with the use of the depression of the die
as a pad to carry out punching.
[0013] To allow the ultrathin metal plate to function as a filter,
it is necessary to provide the ultrathin metal plate with many of
the fine holes (for example, several tens of thousands of the
holes/cm.sup.2), thus requiring that fine depressions be formed in
the die. In actual manufacturing, many of the fine holes need to be
punched at a time, and many of the fine depressions should be
formed in the die. Moreover, alignment of the punch and the die
(concentricity 1 .mu.m or less) is difficult.
[0014] It presents a tremendous difficulty to form many such fine
depressions in the die, or to perform fine alignment corresponding
to concentricity of 1 .mu.m or less. Actually, serious difficulty
is encountered in preparing an ultrathin metal plate having many
fine holes formed therein by use of the punches and the die having
the depressions. Besides, it is expected that the depressions of
the die will be clogged with slugs, or the depressions will be
covered with slugs, whereby tiny damages to the die may be
caused.
[0015] Accordingly, no technologies have been established for
applying an ultrathin metal plate, which has many fine holes formed
therein, to a filter for a liquid-jet head.
SUMMARY OF THE INVENTION
[0016] The present invention has been accomplished in the light of
the foregoing situations. It is an object of the present invention
to provide a die apparatus capable of easily preparing an ultrathin
metal plate which is a work plate having many fine holes formed
therein.
[0017] Also, the present invention has been accomplished in the
light of the above-mentioned situations. It is another object of
the present invention to provide a method for producing a
perforated work plate, which can easily prepare an ultrathin metal
plate being a work plate having many fine holes formed therein.
[0018] Moreover, the present invention has been accomplished in the
light of the aforementioned situations. It is still another object
of the present invention to provide a perforated work plate, which
minimizes a pressure loss and ensures an adequate flow rate of ink,
which can perform a stable function of trapping foreign matter, and
which can be applied as an easy-to-handle filter for a liquid-jet
head.
[0019] Furthermore, the present invention has been accomplished in
the light of the aforementioned situations. It is a further object
of the present invention to provide a liquid-jet head including a
liquid-jet head filter, which minimizes a pressure loss and ensures
an adequate flow rate of ink, which can perform a stable function
of trapping foreign matter, and which is easy to handle; and a
liquid-jet apparatus equipped with the liquid-jet head.
[0020] A first aspect of the present invention for attaining the
above object is a die apparatus for boring a through-hole in a work
plate, comprising a lower receiving die, a punch, and a flexible
member provided between the lower receiving die and the punch, and
wherein the punch is passed through the work plate placed on the
flexible member to press a punched-out piece into the interior of
the flexible member, thereby boring the through-hole in the work
plate.
[0021] In the first aspect, the punched-out piece is pressed into
the interior of the flexible member to bore the through-hole. Thus,
there is no need to form the depression for receiving the punch.
Nor is it necessary to align the depression with the punch.
Accordingly, the work plate having many through-holes formed
therein can be easily prepared.
[0022] A second aspect of the present invention is the die
apparatus according to the first aspect, characterized in that the
flexible member is a polymer material.
[0023] In the second aspect, the hardness of the flexible material
is rendered optimal, so that the punched-out piece can remain
within the flexible member. Since the flexible member is the
polymer material, moreover, when the punch is brought into contact
with the flexible member, the front end of the punch is not
damaged.
[0024] A third aspect of the present invention is the die apparatus
according to the first or second aspect, characterized in that the
thickness of the flexible member is twice or more the thickness of
the work plate.
[0025] In the third aspect, the work plate can be completely passed
through, and the punched-out piece can be allowed to remain
reliably within the flexible member.
[0026] A fourth aspect of the present invention is the die
apparatus according to any one of the first to third aspects,
characterized in that the surface of the lower receiving die facing
the flexible member is flat.
[0027] In the fourth aspect, the surface of the lower receiving die
is flat. Thus, when many punched-out pieces are pressed into the
flexible member, the amounts of indentation are uniform, so that
the many punched-out pieces can be reliably kept within the
flexible member.
[0028] A fifth aspect of the present invention for attaining the
aforementioned object is a method for producing a perforated work
plate by use of a punch and a lower receiving die, comprising
passing the punch through the work plate placed on a flexible
member to press a punched-out piece into an interior of the
flexible member, thereby boring a through-hole in the work
plate.
[0029] In the fifth aspect, the work plate having many of the
through-holes formed therein can be easily prepared.
[0030] A sixth aspect of the present invention is the method for
producing a perforated work plate according to the fifth aspect,
characterized in that the surface of the lower receiving die facing
the flexible member is flat.
[0031] In the sixth aspect, the surface of the lower receiving die
is flat. Thus, when many of the punched-out pieces are pressed into
the flexible member, the amounts of indentation are uniform, so
that the many punched-out pieces can be reliably kept within the
flexible member, A seventh aspect of the present invention is the
method for producing a perforated work plate according to the fifth
or sixth aspect, characterized in that the punched-out piece
pressed into the interior of the flexible member is allowed to
remain in the interior of the flexible member when the punch is
pulled out of the flexible member.
[0032] In the seventh aspect, when the punch is pulled out of the
flexible member, the punched-out piece does not adhere to the
punch. Thus, the perforated work plate can be produced
satisfactorily.
[0033] An eighth aspect of the present invention for attaining the
aforementioned object is a perforated work plate formed by the
method for producing a perforated work plate according to any one
of the fifth to seventh aspects.
[0034] In the eighth aspect, the perforated work plate having no
flash occurring in the circumferential edge of the hole can be
provided.
[0035] A ninth aspect of the present invention for attaining the
aforementioned object is a liquid-jet head having a pressure
generating chamber and a nozzle orifice, and including the
perforated work plate according to the eighth aspect for use in a
filter for the liquid-jet head which traps foreign matter contained
in a liquid to be supplied to the pressure generating chamber.
[0036] In the ninth aspect, there can be provided a liquid-jet head
having a filter for the liquid-jet head which can more reliably
remove foreign matter contained in ink.
[0037] A tenth aspect of the present invention is the liquid-jet
head according to the ninth aspect, characterized in that the
filter for the liquid-jet head is a filter sheet consisting of a
metal film alone, has a plurality of the through-holes formed in
the filter, and has irregularity lines formed on a surface of the
filter, the irregularity lines extending in a lattice pattern.
[0038] In the tenth aspect, the filter for the liquid-jet head is a
filter having a plurality of the through-holes formed therein.
Thus, the resulting liquid-jet head is a liquid-jet head having a
filter which ensures the adequate flow rate of ink while minimizing
a pressure loss, and which can perform the stable function of
trapping foreign matter. Furthermore, the irregularity lines are
formed on the surface of the filter. Thus, the liquid-jet head is a
liquid-jet head having a filter which eliminates a curling force
(residual stress in the bending direction based on the boring of
the many through-holes), thereby maintaining a flat state, and thus
is easy to handle. In addition, even when mounted in the head, the
filter is in a flat state and free from waves, so that changes in
the shape of the through-holes due to waves do not occur, and
foreign matter in the ink can be reliably removed.
[0039] An eleventh aspect of the present invention is the
liquid-jet head according to the tenth aspect, characterized in
that the size of the through-hole of the filter is the size of the
nozzle orifice or smaller.
[0040] In the eleventh aspect, clogging of the nozzle orifice with
foreign matter can be reliably prevented.
[0041] A twelfth aspect of the present invention for attaining the
aforementioned object is a liquid-jet apparatus including the
liquid-jet head according to any one of the tenth to eleventh
aspects.
[0042] In the twelfth aspect, there can be provided a liquid-jet
apparatus having a filter which ensures the adequate flow rate of
ink while minimizing a pressure loss, can perform the stable
function of trapping foreign matter, and maintains a flat state,
thus facilitating handling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] For a more complete understanding of the present invention
and the advantages thereof, reference is now made to the following
descriptions in conjunction with the accompanying drawings.
[0044] FIG. 1 is a schematic configurational drawing of an ink-jet
recording apparatus.
[0045] FIG. 2 is a sectional view of a main portion of an ink-jet
head.
[0046] FIG. 3 is a sectional view showing the whole of the ink-jet
head.
[0047] FIGS. 4A and 4B are explanation drawings of a filter.
[0048] FIGS. 5A to 5C are explanation drawings of a state of
punching.
[0049] FIGS. 6A and 6B are operational explanation drawings of a
punching step.
[0050] FIG. 7 is an operational explanation drawing of a
curl-removing step.
[0051] FIGS. 8A and 8B are views illustrating the status of
formation of irregularity lines.
[0052] FIGS. 9A and 9B are explanation drawings of a punch
according to another embodiment.
[0053] FIGS. 10A and 10B are explanation drawings of a punch
according to still another embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] An ink-jet recording apparatus, to which a work plate
prepared by a method for producing a perforated work plate
according to an embodiment of the present invention has been
applied as a filter, will be described with reference to FIGS. 1 to
3. A perforated work plate has been prepared using a die apparatus
according to an embodiment of the present invention. That is, the
perforated work plate is used as a filter for trapping foreign
matter contained in a liquid to be supplied to a pressure
generating chamber of an ink-jet head.
[0055] FIG. 1 shows the schematic configuration of an ink-jet
recording apparatus furnished with a liquid-jet head filter formed
with the use of a die apparatus according to the present invention.
FIG. 2 shows the section of a main portion of an ink-jet head
(liquid-jet head). FIG. 3 shows a section showing the whole of the
ink-jet head.
[0056] An ink-jet recording apparatus (apparatus body) 1 includes
an ink-jet head 5 integrated with a carriage 3 installed with an
ink cartridge 2, and a recording head 4 mounted on the carriage 3.
The carriage 3 is connected to a stepping motor 7 via a timing belt
6, and is guided by a guide bar 8 to reciprocate in the sheet width
direction (main scanning direction) of a recording sheet 9. The
carriage 3 is in the shape of a box opening upwards, and the
recording head 4 is mounted on the carriage 3 such that the nozzle
surface of the recording head 4 is exposed at the surface (lower
surface) of the carriage 3 opposed to the recording sheet 9. In
this state, the ink cartridge 2 is accommodated in the carriage
3.
[0057] The recording head 4 is supplied with ink from the ink
cartridge 2 and, with the carriage 3 being moved, the recording
head 4 ejects ink droplets onto the upper surface of the recording
sheet 9, thereby printing images and characters on the recording
sheet 9 by dot matrices. Of the numerals in FIG. 1, 10 denotes a
cap for sealing nozzle orifices of the recording head 4 during
stoppage of printing to prevent drying of the nozzles, and exerting
a negative pressure on the nozzle surface of the recording head 4
to perform a cleaning action; 11 denotes a wiper blade for wiping
the nozzle surface of the recording head 4; 12 denotes a waste ink
reservoir for storing waste ink sucked by the cleaning action; and
13 denotes a control device for controlling the actions of the
apparatus body 1.
[0058] As shown in FIG. 2, the ink-let head 5 (see FIG. 1) is
provided with a control plate 15, and an action signal from the
control device 13 (see FIG. 1) is entered into a piezoelectric
vibrator 16 (to be described later) via the control plate 15. The
control plate 15 is disposed at a site of a head case 18 on a side
opposite to a passage unit 17, namely, along the upper surface of
the head case 18.
[0059] The structure of the recording head 4 will be explained
based on FIG. 2.
[0060] In the recording head 4, the passage unit 17 is disposed at
a front end portion of the recording head 4, and a nozzle plate 19
having nozzle orifices 20 arranged in rows in a nozzle formation
surface 19a is provided in the passage unit 17. A pressure
generating chamber 21, which communicates with the nozzle orifice
20 and pressurizes ink by the action of the piezoelectric vibrator
16, is provided, and the pressure generating chamber 21 is supplied
with ink from an ink storage chamber 22.
[0061] That is, the passage unit 17 comprises the nozzle plate 19,
a pressure generating chamber forming plate 24, and a vibration
plate 25 laminated together, the nozzle plate 19 having the nozzle
formation surface 19a having the nozzle orifices 20 bored therein;
the pressure generating chamber forming plate 24 having formed
therein a space corresponding to the pressure generating chambers
21, the ink storage chamber 22 as a liquid storage chamber common
to the pressure generating chambers 21, and ink supply paths 23 in
communication with the pressure generating chambers 21 and the ink
storage chamber 22; and the vibration plate 25 being a sealing
plate for sealing the openings of the pressure generating chambers
21 and the ink storage chamber 22. The nozzle formation surface 19a
is a flat surface. The passage unit 17 is joined to the front end
surface 18a of the head case 18 with the use of an adhesive
agent.
[0062] The piezoelectric vibrator 16 is a vibrator in a so-called
longitudinal vibration mode which contracts in a longitudinal
direction in a charged stated upon receipt of a drive signal, and
expands in the longitudinal direction during the process of
discharge from the charged state. The piezoelectric vibrator 16 has
a front end secured to an island portion 25a of the vibration plate
25, which forms a part of the pressure generating chamber 21, and
has the other end fixed to a foundation 26. The piezoelectric
vibrator 16 in the longitudinal vibration mode may be replaced by a
piezoelectric vibrator in a flexural vibration mode.
[0063] In the head case 18, a head passage 27 is formed in a
portion corresponding to the ink storage chamber 22. Ink of the ink
cartridge 2 (see FIG. 1) is introduced into the ink storage chamber
22 via the head passage 27. A flexible circuit plate 28 is
connected to the piezoelectric vibrator 16, which receives a drive
signal from the control plate 15. A flexible circuit plate 29,
which transmits an action signal from the control device 13 (see
FIG. 1) for operating the whole of the apparatus body 1 (see FIG.
1) to the control plate 15, is connected to the control plate 15
via a terminal 30.
[0064] In the recording head 4, the pressure generating chamber 21
contracts and expands upon the contraction and expansion of the
piezoelectric vibrator 16, and the suction of ink and the ejection
of ink droplets are performed according to changes in the pressure
of the pressure generating chamber 21. The nozzle plate 19 has
nozzles formed in plural pairs of rows, each pair being constituted
by two rows of the nozzles. A head cover 14 for protecting the
nozzle formation surface 9a is provided. The head cover 14 prevents
an unsmooth action, or scars to the corner of the passage unit 17,
because of the wiper blade 11 (see FIG. 1) being rubbed against the
corner of the passage unit 17 during wiping of the nozzle formation
surface 19a.
[0065] Ink fed from the ink cartridge (see FIG. 1) flows from the
head passage 27 into the ink storage chamber 22. Then, the ink is
pressurized in the pressure generating chamber 21 by the action of
the piezoelectric vibrator 16, and is ejected, as ink droplets,
through the nozzle orifice 20 toward the recording sheet 9 (see
FIG. 1) to proceed with printing.
[0066] The entire configuration of the ink-jet head 5 will be
described with reference to FIG. 3.
[0067] As shown in FIG. 3, the ink-jet head 5 is constructed, with
the recording head 4 being coupled to a head holder 41
corresponding to the carriage 3 (see FIG. 1). A plate-shaped member
41a is disposed in an upper portion of the head holder 41, and ink
supply pins 31, which enter the ink cartridge 2 (see FIG. 1), are
attached to the plate-shaped member 41a. A passageway inside the
ink supply pin 31 communicates with an introduction passage 33 via
a filter 32, and the introduction passage 33 is formed by an
introduction pipe 34 provided on the underside of the plate-shaped
member 41a.
[0068] An annular protrusion 42 at an upper portion of the head
case 18 passes through the control plate 15, and the head passage
27 and the introduction passage 33 are disposed coaxially. The head
passage 27 and the introduction passage 33 are connected while
being sealed with a packing member 35, and the packing member 35 is
composed of an elastic material such as an elastomer. The head case
18 is mounted on the head holder 41 via the packing member 35,
whereby the packing member 35 is compressed between the end surface
of the introduction pipe 34 and the end surface of the annular
protrusion 42. According to such a passage structure, when the ink
supply pins 31 are relatively inserted into the ink cartridge 2
serving as a fluid supply source, ink is supplied to the passage
unit 17.
[0069] The filter 32 provided in the above-described apparatus body
1 is produced by the method for producing a perforated work plate
according to an embodiment of the present invention. A die
apparatus according to the embodiment of the present invention is
used for its production.
[0070] The filter 32 will be described with reference to FIGS. 4A
and 4B.
[0071] FIG. 4A shows a plan illustrating the whole of the filter
32, and FIG. 4B shows an enlarged state of the essential part of
the filter 32.
[0072] As shown in these drawings, the filter 32 is formed by
boring many fine holes 52 (for example, several tens of thousands
of the holes/cm.sup.2, each hole having a diameter of 15 .mu.m),
which are through-holes, in a flat work plate (filter sheet: for
example, 15 .mu.m in thickness) 51 made of stainless steel (SUS),
and cutting the perforated work plate into a circular form. That
is, the filter 32 is composed of a filter sheet consisting of a
metal film. The diameter of the filter 32 is, for example, of the
order of 8 to 9 mm, and the diameter of the fine hole 52 is set to
be smaller than that of the nozzle orifice 20 (see FIG. 2).
[0073] The hole of the filter 32 may be a square hole or a
hexagonal hole. In this case, it suffices for the length of the
diagonal line of the hole to be set to be smaller than the nozzle
orifice 20 (see FIG. 2).
[0074] Irregularity lines 53 extending in a lattice pattern are
formed on the flat work plate 51 to eliminate a curling force
(residual stress in a bending direction based on the boring of the
many fine holes 52), thereby maintaining a flat state. By providing
the irregularity lines 53, curls are eliminated, and a flat state
is maintained, even in the filter 32 which is ultrathin. Thus, its
handling is easy, making it possible to increase productivity
during assemblage.
[0075] Even when mounted in the ink-jet head 5 (see FIG. 1), the
filter 32 is in a flat state, and is not wavy. Thus, changes in the
shape of the fine holes 52 due to waves do not occur, so that
foreign matter in the ink can be reliably removed.
[0076] The pitch of the fine hole 52 with respect to the adjacent
fine hole 52 is set to be, for example, of the order of 4 .mu.m.
The irregularity line 53 has a ridge height set at a value, for
example, of the order of 20 to 50 .mu.m, and has a pitch, with
respect to the adjacent irregularity line 53, set to be, for
example, of the order of 60 .mu.m.
[0077] A die apparatus used for producing the filter 32 will be
described with reference to FIGS. 5A to 5C through FIGS. 8A and
8B.
[0078] FIG. 5A shows a section of a state in which punching is
performed by the die apparatus according to an embodiment of the
present invention. FIG. 5B shows a section of a work plate and a
flexible member after punching. FIG. 5C shows a plan of the work
plate and the flexible member after punching. FIGS. 6A and 6B offer
an operational explanation for a punching step. FIG. 7 offers an
operational explanation for a curl-removing step. FIGS. 8A and 8B
illustrate the status of formation of the irregularity lines.
[0079] The configuration of the die apparatus will be described
with reference to FIGS. 5A to 5C.
[0080] As shown in FIG. 5A, a die apparatus 54 has a round punch
tool 57 provided via a stripper 56 above a flat board-shaped lower
receiving die 55 having no irregularities formed therein. On the
upper surface of the lower receiving die 55, PET (polyethylene
terephthalate: polymer material) 58 is provided as a flexible
member. The diameter of the front end 57a (punch) of the round
punch tool 57 corresponds to the diameter of the fine hole 52 of
the filter 32, and the front end 57a of the round punch tool 57 is
to be inserted into the PET 58. The surface of the lower receiving
die 55 facing the PET 58 has no irregularities, and is flat. Thus,
when many punched-out pieces 62 of the work plate 51 are pressed
into the PET 58, the amount of indentation is uniform, so that the
many punched-out pieces 62 can be reliably kept within the PET
58.
[0081] As the polymer material for the flexible material, PC
(polycarbonate), POM (polyacetal), ABS (ABS resin), and PPS
(polyphenylene sulfide) can be used. The hardness of the flexible
material can be selected variously according to the thickness of
the work plate, the size and pitch of the fine hole, and so
forth.
[0082] In the above-mentioned die apparatus 54, the work plate 51
is placed on the PET 58, and the front end 57a of the round punch
tool 57 is passed through the work plate 51 to punch the fine hole
52. At this time, the front end 57a of the round punch tool 57 that
has passed through the work plate 51 is inserted into the PET 58,
and the punched-out piece 62 remains within the PET 58. That is,
states as shown in FIGS. 8B and 5C are observed. Thus, the fine
hole 52 can be punched without the need to provide on the die side
a depression for receiving the front end 57a of the round punch
tool 57.
[0083] The thickness of the PET 58 is at least twice the thickness
of the work plate 51, and is preferably of the order of 0.1 mm to
0.2 mm. By adopting such a thickness of 0.1 to 0.2 mm, the
punched-out piece 62 can be reliably allowed to remain within the
PET 58 without rendering the thickness of the PET 58 larger than
necessary. Besides, the work plate 51 can be completely penetrated.
Thus, there is no flash occurring at the circumferential edge of
the fine hole 52 due to poor penetration.
[0084] Hence, the use of the above-described die apparatus 54
enables the fine hole 52 to be bored, with the punched-out piece 62
remaining within the PET 58, Consequently, there is no need to form
the depression receiving the front end 57a of the round punch tool
57. Nor is it necessary to align the depression with the front end
57a of the round punch tool 57. Accordingly, the work plate 51
having the fine holes 52 formed therein can be easily prepared.
[0085] The actions in the punching step will be described with
reference to FIGS. 6A and 6B.
[0086] As shown in FIG. 6A, the stripper 56 is moved toward the
lower receiving die 55, whereby the front end 57a of the round
punch tool 57 is driven into the work plate 51, with the result
that the front end 57a of the round punch tool 57 and the
punched-out piece 62 are inserted into the PET 58. The stripper 56
is raised and, with the punched-out piece 62 being left within the
PET 58, the work plate 51 is moved, together with the PET 58, by
one pitch, whereafter the front end 57a of the round punch tool 57
is driven into the work plate 51 again. By repeating this action,
many of the fine holes 52 are formed in the work plate 51.
[0087] As noted above, the operation of moving the work plate 51,
along with the PET 58, by one pitch, and driving the front end 57a
of the round punch tool 57 into the work plate 51 is repeated.
Thus, even if a burr occurs, there is no possibility for the
occurrence of a lateral burr due to the burr being crushed by the
end surface of the stripper 56. Incidentally, if a die having a
depression for insertion of the front end 57a of the round punch
tool 57 is placed below, and used, the movement of the work plate
may result in the crushing of the burr between the upper surface of
the die other than the depression and the end surface of the
stripper 56, thereby deforming the fine hole 52. The use of the
above-described die apparatus 54 is free from the possibility for
deformation of the fine hole 52.
[0088] If the PET 58 was used, a burr measuring about 4 to 5 .mu.m
was seen, but little damage to the round punch tool 57 was
confirmed. If PC harder than the PET 58 was used, a burr of the
order of 2 to 3 .mu.m was observed. These findings demonstrate that
the use of the PET 58 can suppress a burr, and minimize damage to
the round punch tool 57. The use of a hard flexible material can
reduce a burr.
[0089] Actions for a curl-removing step will be described with
reference to FIG. 7.
[0090] The work plate 51 having many of the fine holes 52 formed
therein is punched by an oval product punching die 65 to be formed
into the shape of the filter 32. Irregularities 66 for forming the
irregularity lines 53 are provided on the opposed surfaces of an
upper die 65a and a lower die 65b of the oval product punching die
65. Simultaneously with the punching-out of the shape of the filter
32, the irregularity lines 53 (see FIGS. 4A and 4B) are formed on
the surface of the filter 32.
[0091] As shown in FIG. 8A, the irregularity lines 53 can be formed
on the entire surface of the filter 32. Alternatively, as shown in
FIG. 8B, the irregularity lines 53 can be formed, with a welding
margin 67 being left intact on the periphery of the filter 32.
[0092] By using the oval product punching die 65 (see FIG. 7)
provided with the irregularities 66 (see FIG. 7), pressurization
and correction can be performed at the same time during
punching-out of the oval product.
[0093] Thus, the above-mentioned filter 32 ensures the adequate
flow rate of ink while minimizing a pressure loss, and can perform
the stable function of trapping foreign matter. Furthermore, its
handling is easy. Hence, it can be used as the filter 32 for the
ink-jet head, which traps foreign matter contained in the ink to be
supplied to the pressure generating chamber 21 of the ink-jet head
5 having the pressure generating chambers 21 and the nozzle
orifices 20.
[0094] Other embodiments of the punch will be described with
reference to FIGS. 9A, 9B and FIGS. 10A, 10B.
[0095] A punch tool 71 shown in FIG. 9A has a plurality of (16 in
the illustrated embodiment) square-shaped front end portions 73
(punches) provided on the end surface of a cubic body 72
(pin-implanted holder type) One side of the front end portion 73 is
formed with a dimension, for example, of 13 .mu.m, whereas the
length of the diagonal line of a fine hole 74 of a work plate 51 is
set at about 15 .mu.m, as shown in FIG. 9B. The shape of the front
end portion 73 may be circular.
[0096] By using the punch tool 71 shown in FIG. 9A, a plurality of
(16 in the illustrated embodiment) the fine holes 74 can be formed
by single punching.
[0097] A punch tool 81 shown in FIG. 10A has a plurality of (5 in
the illustrated embodiment) square-shaped front end portions 83
(punches) provided on the end surface of a rectangular
parallelopipedal body 82 (comb-toothed type). One side of the front
end portion 83 is formed with a dimension, for example, of 13
.mu.m, as with the one shown in FIG. 9A. On the other hand, the
length of the diagonal line of a fine hole 84 of a work plate 51 is
set at about 15 .mu.m, as shown in FIG. 10B. The shape of the front
end portion 83 may be circular.
[0098] By using the punch tool 81 shown in FIG. 10A, a plurality of
(S in the illustrated embodiment) the fine holes 84 can be formed
by single punching.
[0099] Accordingly, the use of the punch tools 71 and 81 shown in
FIGS. 9A and 10A enables a plurality of fine holes to be formed by
single punching, and makes it possible to increase the efficiency
of manufacturing without raising the speed of the punching
apparatus.
[0100] While the present invention has been described by the
foregoing embodiments, it is to be understood that the invention is
not limited thereby, but may be varied in many other ways. Such
variations are not to be regarded as a departure from the spirit
and scope of the invention, and all such modifications as would be
obvious to one skilled in the art are intended to be included
within the scope of the appended claims.
* * * * *