U.S. patent application number 11/501080 was filed with the patent office on 2007-02-22 for method of manufacturing nozzle for inkjet head.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Jae-Woo Joung, Soon Young Kim, Won-Chul Sim, Young-Seuck Yoo.
Application Number | 20070039180 11/501080 |
Document ID | / |
Family ID | 37621694 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070039180 |
Kind Code |
A1 |
Yoo; Young-Seuck ; et
al. |
February 22, 2007 |
Method of manufacturing nozzle for inkjet head
Abstract
A method of manufacturing a nozzle for an inkjet head is
disclosed. With the method of manufacturing a nozzle for an inkjet
head, comprising (a) coating photoresist on an inkjet head
structure comprising a nozzle part; (b) adjusting exposure
conditions and performing exposure and developing on the nozzle
part to remove a portion of the photoresist; (c) joining a
hydrophobic layer onto the portion of the nozzle part where the
photoresist has been removed; and (d) removing the photoresist
remaining on the nozzle part, it is easy to control the depth of
the hydrophobic layer to be uniform, and the depth to which the
hydrophobic layer is deposited may be controlled even when the back
surface of the nozzle has a complex shape, so that the uniformity
and reproduction of the hydrophobicity-treated nozzles are
improved.
Inventors: |
Yoo; Young-Seuck; (Seoul,
KR) ; Kim; Soon Young; (Yongin-si, KR) ; Sim;
Won-Chul; (Seongnam-si, KR) ; Joung; Jae-Woo;
(Suwon-si, KR) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
37621694 |
Appl. No.: |
11/501080 |
Filed: |
August 9, 2006 |
Current U.S.
Class: |
29/890.1 |
Current CPC
Class: |
B41J 2/162 20130101;
B41J 2/1623 20130101; Y10T 29/49401 20150115; B41J 2/1631 20130101;
B41J 2/1643 20130101 |
Class at
Publication: |
029/890.1 |
International
Class: |
B21D 53/76 20060101
B21D053/76 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2005 |
KR |
10-2005-0075415 |
Claims
1. A method of manufacturing a nozzle for an inkjet head, the
method comprising: (a) coating photoresist on an inkjet head
structure comprising a nozzle part; (b) adjusting exposure
conditions and performing exposure and developing on the nozzle
part to remove a portion of the photoresist; (c) joining a
hydrophobic layer onto the portion of the nozzle part where the
photoresist has been removed; and (d) removing the photoresist
remaining on the nozzle part.
2. The method of claim 1, wherein the head structure further
comprises any one or more of a pressure chamber, an ink injection
channel, and a manifold.
3. The method of claim 1, wherein the photoresist is a liquid.
4. The method of claim 1, wherein the exposure conditions include
exposure time or exposure amount.
5. The method of claim 1, wherein the hydrophobic layer comprises
Teflon-based material or parylene.
6. The method of claim 1, wherein the hydrophobic layer is joined
by vacuum deposition or by plating.
7. The method of claim 1, wherein the operation (b) further
comprises adjusting the exposure conditions so that the photoresist
coated on an outer surface of the nozzle part is sensitized.
8. The method of claim 1, wherein the operation (b) further
comprises adjusting the exposure conditions so that the photoresist
is sensitized up to a predetermined depth of the nozzle.
9. The method of claim 8, wherein the predetermined depth is
uniform along the inner perimeter of the nozzle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Application No. 2005-75415 filed with the Korea Industrial Property
Office on Aug. 17, 2005, the disclosure of which is incorporated
herein by reference in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a nozzle, more specifically
to a nozzle for an inkjet head and a manufacturing method
thereof.
[0004] 2. Description of the Related Art
[0005] An inkjet printer is a device for printing operations, in
which power is supplied to a pressure chamber formed within the
head so that ink droplets are sprayed through nozzles. The ink
sprayed through nozzles is typically sprayed in the form of
droplets and for improved printing performance of the inkjet head,
the ink has to be sprayed in the form of complete droplets in a
stable manner.
[0006] Thus, the nozzle region of an inkjet head requires
hydrophobicity treatment, where the hydrophobicity treatment allows
the menisci of the ink droplets to be formed adequately.
[0007] In general, the problem of a lack of hydrophobicity in the
surface of a nozzle in an inkjet head is caused by wetting, where
the nozzle surface is wetted due to repeated spraying. When such
wetting occurs, the ink being sprayed forms a lump with the ink
wetting the surface of the nozzle, whereby the sprayed ink does not
retain the form of a complete droplet and flows down. As a result,
the quality of the printing is degraded, and the menisci formed
after the spraying of ink droplets become unstable. Thus, to
guarantee reliable inkjet printing, it is essential to provide
effective hydrophobicity treatment on the nozzle surface of an
inkjet head.
[0008] For the hydrophobicity treatment of an inkjet head nozzle,
such methods were used in prior art as forming the nozzle by
electroplating, and forming the nozzle by micro-punching and
ablation processes, etc. The outlet region of a nozzle formed by
the above methods is an important factor affecting the size of an
ink droplet, ink spray performance, ink spray stability, and
continuous spraying.
[0009] The conventional method of electroplating is to provide a
semi-permanent hydrophobicity treatment on the nozzle surface of an
inkjet printer head by plating with a hydrophobic material in a
plating bath on which an electric field having a particular set of
conditions is applied. Here, Teflon-based materials are mainly used
as the hydrophobic material, representative of which is PTFE
(polytetrafluoroethylene).
[0010] To perform hydrophobicity treatment on the surface of a
nozzle using PTFE, a method is used of performing composite plating
treatment in a plating bath on which an electric field having a
particular set of conditions is applied. Since this method of
hydrophobicity treatment using composite plating has no
directionality, a hydrophobic layer is formed not only on the
surface of the nozzle where a hydrophobic layer is desired, but
also on the back surface of the nozzle where a hydrophobic layer is
not desired.
[0011] Thus, when providing hydrophobicity treatment using
composite plating, a preliminary process is additionally required
for preventing the formation of a hydrophobic layer on the back
surface of the nozzle. That is, to provide hydrophobicity treatment
only on the surface of the nozzle, an insulation film was first
formed on the back surface of the nozzle with a non-conductive
matter and the plating of a hydrophobic layer was performed
afterwards in prior art, so that a hydrophobic layer was not formed
on the back surface of the nozzle.
[0012] Here, a representative material used as the insulation film
is photoresist, and a method of forming an insulation film on the
back surface of a nozzle is as shown in FIG. 1. FIG. 1 is a
schematic diagram illustrating a method of hydrophobicity treatment
on a nozzle for an inkjet head by composite plating according to
prior art.
[0013] Before performing hydrophobicity treatment on the nozzle 10
as in FIG. 1, an insulation film 12 is formed on the back surface
of the nozzle 10 by coating photoresist via screen printing, etc.
After forming the insulation film 12, a hydrophobic layer 14 of
PTFE is formed on the surface of the nozzle 10 generally by
composite plating processes.
[0014] FIG. 2 is a schematic diagram illustrating a method of
hydrophobic treatment on a nozzle for an inkjet head by vacuum
deposition according to prior art, where the linear directionality
of vacuum deposition is used to form a uniform non-conductive thin
film on the back surface of the nozzle, and an overall plating of
hydrophobic material is applied on the front surface of the
nozzle.
[0015] Before performing hydrophobicity treatment on the front
surface of the nozzle 30 as in FIG. 2, a non-conductive thin film
32 is formed on the back surface of the nozzle 30 by vacuum
deposition. Teflon-based material is plated on the front surface of
the nozzle 30 on which the non-conductive thin film 32 has been
formed, to obtain a hydrophobic layer 34. After the hydrophobic
layer 34 is formed, the nozzle 30 is heat-treated to complete the
hydrophobicity treatment.
[0016] In general, the hydrophobic layer of a nozzle in an inkjet
head is positioned at the inlet of the nozzle, and is formed up to
several .mu.m into the interior. With the conventional methods
described above for forming a hydrophobic layer on a nozzle of an
inkjet head, it is difficult to completely prevent a hydrophobic
layer being deposited on the back surface of the nozzle, and it is
difficult also to control the hydrophobic layer to be formed in a
uniform depth into the interior of the nozzle. Thus, the sizes of
the droplets may not be uniform during the spraying, with lowered
reliability for repeated printing.
[0017] Also, the conventional methods described above involve
complicated processes, so that it is difficult to manage the
process conditions, and with these methods, the yield of nozzle
plates coated for hydrophobicity treatment is low, or the degree of
coating is not uniform.
[0018] With regards examples of prior art related to the
hydrophobicity treatment of a nozzle for an inkjet head, firstly,
the technique of forming a hydrophobic layer in a stable manner
using contact printing entails the problem that it is difficult to
form the hydrophobic layer in a uniform depth into the nozzle.
[0019] Secondly, for the technique of controlling the depth of the
hydrophobic layer by forming an insulation film only on the back
surface of the nozzle, since the depth of the hydrophobic layer is
determined during the process of forming the insulation film,
controlling the depth of the hydrophobic layer to be uniform is
performed with low precision.
[0020] Thirdly, the technique of using photolithography is limited
in that there has not yet been disclosed a process of adjusting the
exposure conditions for controlling the depth of the hydrophobic
layer to be uniform. That is, the prior art is limited in that the
present invention cannot readily be derived, an aspect of which
comprises controlling the depth of the hydrophobic layer to be
uniform, by coating liquid photoresist on the entire nozzle part,
adjusting the exposure conditions, and removing the photoresist
layer.
SUMMARY
[0021] The present invention aims to provide a method of
manufacturing a nozzle for an inkjet head, with which it is easy to
control the depth of the hydrophobic layer to be uniform, as the
hydrophobic layer is formed on the nozzle of the inkjet head using
photolithography, and with which the deposition depth of the
hydrophobic layer can be controlled to be uniform even when the
back surface of the nozzle has a complex shape.
[0022] One aspect of the present invention provides a method of
manufacturing a nozzle for an inkjet head, comprising (a) coating
photoresist on an inkjet head structure comprising a nozzle part;
(b) adjusting exposure conditions and performing exposure and
developing on the nozzle part to remove a portion of the
photoresist; (c) joining a hydrophobic layer onto the portion of
the nozzle part where the photoresist has been removed; and (d)
removing the photoresist remaining on the nozzle part.
[0023] The head structure further may comprise any one or more of a
pressure chamber, an ink injection channel, and a manifold.
Preferably, the photoresist may be a liquid. The exposure
conditions may include exposure time or exposure amount.
[0024] The hydrophobic layer may comprise Teflon-based material or
parylene. Preferably, the hydrophobic layer may be joined by vacuum
deposition or by plating.
[0025] Operation (b) may further comprise adjusting the exposure
conditions so that the photoresist coated on an outer surface of
the nozzle part is sensitized. Operation (b) may further comprise
adjusting the exposure conditions so that the photoresist is
sensitized up to a predetermined depth of the nozzle. It may be
preferable for the predetermined depth to be uniform along the
inner perimeter of the nozzle.
[0026] Additional aspects and advantages of the present invention
will be set forth in part in the description which follows and, in
part, will be apparent from the description, or may be learned by
practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic diagram illustrating a method of
performing hydrophobicity treatment on a nozzle for an inkjet head
by composite plating according to prior art.
[0028] FIG. 2 is a schematic diagram illustrating a method of
hydrophobic treatment on a nozzle for an inkjet head by vacuum
deposition according to prior art.
[0029] FIG. 3 is a cross-sectional view illustrating the nozzle
part of a nozzle for an inkjet head.
[0030] FIG. 4 is a flowchart illustrating a method of manufacturing
a nozzle for an inkjet head according to an embodiment of the
present invention.
[0031] FIG. 5 is a schematic diagram illustrating a process of
manufacturing a nozzle for an inkjet head according to an
embodiment of the present invention.
DETAILED DESCRIPTION
[0032] Embodiments of the invention will now be described in more
detail with reference to the accompanying drawings, wherein like
reference numerals refer to the like elements throughout, and
redundant explanations are omitted.
[0033] FIG. 3 is a cross-sectional view illustrating the nozzle
part of a nozzle for an inkjet head. In FIG. 3 are illustrated a
nozzle part 120a, a nozzle hole 120, and a hydrophobic layer 141.
An aspect of the present invention is for controlling the depth of
the hydrophobic layer formed on the nozzle of the inkjet head to be
uniform, and is characterized by using photolithography for
precision control of the depth to which the hydrophobic layer is
formed into the nozzle hole, as compared to conventional techniques
of depositing an insulation film and afterwards plating the
hydrophobic layer.
[0034] That is, as illustrated in FIG. 3, the hydrophobic layer is
formed up to a predetermined depth into the nozzle hole so that the
menisci of the ink droplets are formed adequately. Thus, with the
present invention, photoresist is coated overall on the surface of
the nozzle part, after which the exposure conditions are adjusted,
such as exposure time, exposure amount, etc., to precisely adjust
the degree of sensitivity of the photoresist on the outer surface
of the nozzle part and inside the nozzle hole. Then, the
photoresist layer is removed, and the hydrophobic layer is
deposited, so that the deposition depth of the hydrophobic layer
may be controlled.
[0035] FIG. 4 is a flowchart illustrating a method of manufacturing
a nozzle for an inkjet head according to an embodiment of the
present invention.
[0036] To form a hydrophobic layer on a nozzle for an inkjet head
according to the present embodiment, first, photoresist is coated
overall on the surface of the inkjet head structure (50). The
nozzle part is included in the inkjet head structure, and in
addition, a pressure chamber, ink injection channels, and a
manifold, etc., may also be included.
[0037] An aspect of the present invention is for controlling the
depth to which the hydrophobic layer is deposited by coating
photoresist overall on the surface of the inkjet head structure and
afterwards selectively removing the photoresist in portions where
the hydrophobic layer is to be deposited. Thus, unlike in prior
art, the hydrophobic layer may readily be formed uniformly even
when various components of the inkjet head are already formed.
[0038] That is, according to the present invention, the same
process is utilized for the case of forming the various components
of the head after forming the nozzle part of the inkjet head and
depositing the hydrophobic layer, and for the case of depositing
the hydrophobic layer on the nozzle part while the components of
the head are already formed. Thus, not only is it possible to
deposit the hydrophobic layer on the nozzle part after the
components of the head are already formed, but also it can be
performed easily without any particular technical difficulties.
[0039] In order to thus readily coat photoresist on the head
structure, it is advantageous to form a photoresist coating layer
on the outer surface of the inkjet head structure by methods of
overall coating, spraying, and precipitating, etc., using liquid
photoresist. However, the present invention is not limited to the
above methods for the method of coating photoresist, and it is to
be appreciated that any method may be included that provides a
coating layer evenly formed on the outer surface of the inkjet head
structure, within a scope apparent to those skilled in the art.
[0040] Next, exposure and developing are performed on the nozzle
part to remove portions of the photoresist (60). The photoresist is
a light-sensitive material, which undergoes a change in its
properties when exposed to ultraviolet rays, etc., so that it is
possible to selectively remove or leave certain areas. In general,
there are specified exposure conditions, such as exposure time and
exposure amount, etc., established by the manufacturer for
sensitizing the photoresist by a required amount.
[0041] Therefore, by exposing and developing the surface of the
nozzle part under the appropriate exposure conditions, the
photoresist may be selectively removed only in the portions
necessary. Also, as illustrated in FIG. 3, in order to deposit the
hydrophobic layer up to a predetermined depth into the nozzle, the
photoresist must be removed in the nozzle up to a predetermined
depth before depositing the hydrophobic layer, where this may be
achieved by adjusting the exposure time or exposure amount.
[0042] The appropriate depth to which the hydrophobic layer is
formed into the nozzle hole varies according to the shape of the
nozzle part, and in some cases, it may be advantageous to form the
hydrophobic layer only on the surface around the nozzle hole, i.e.
without the hydrophobic layer formed within the nozzle hole. In
such cases, the exposure conditions are adjusted so that only the
photoresist coated on the outer surface of the nozzle part is
sensitized.
[0043] On the other hand, in order for the hydrophobic layer to be
deposited up to a predetermined depth in the end of the nozzle
hole, the exposure conditions are adjusted so that the photoresist
is sensitized up to the predetermined depth of the nozzle. Of
course, to allow the menisci of the ink droplets to be formed
adequately, the exposure conditions are adjusted so that the depth
to which the photoresist is sensitized, i.e. the depth to which the
hydrophobic layer is deposited, is made uniform along the inner
perimeter of the nozzle.
[0044] Next, the hydrophobic layer is joined to the portions of the
nozzle part where the photoresist has been removed (70). It is
apparent to those skilled in the art that while the hydrophobic
layer may be joined according to conventional methods such as
vacuum deposition or plating, etc., a physical joining method may
also be applied which can be implemented in a single
photolithography process without a separate plating process, etc.
As the process for joining the hydrophobic layer is apparent to
those skilled in the art, detailed explanations on this matter are
not provided.
[0045] As mentioned above, it is advantageous for the hydrophobic
layer to comprise Teflon-based material or parylene. The material
for the hydrophobic layer is also apparent to those skilled in the
art, and detailed explanations on this matter are not provided.
[0046] Finally, the process of forming the hydrophobic layer on the
nozzle for an inkjet is completed by removing the photoresist
remaining on the nozzle part (80). The method of removing the
photoresist is apparent to those skilled in the art, and detailed
explanations on this matter are not provided.
[0047] FIG. 5 is a schematic diagram illustrating a process of
manufacturing a nozzle for an inkjet head according to an
embodiment of the present invention. In FIG. 5 are illustrated a
nozzle part 120, a nozzle hole 122, photoresist 124, 124a, and a
hydrophobic layer 141.
[0048] The process of forming the hydrophobic layer 141 on the
nozzle part 120 of the inkjet head according to the present
embodiment will be described with reference to FIG. 5. Onto the
surface of the nozzle part 120 of the inkjet head, formed such as
that in (a) of FIG. 5, liquid photoresist 124 is coated overall, as
in (b) of FIG. 5.
[0049] Then, taking into account the depth into the nozzle hole 122
to which the hydrophobic layer 141 will be deposited, exposure and
developing are performed on the outer surface of the nozzle part
120 as in (c) of FIG. 5. The depth of the hydrophobic layer 141 of
the nozzle for the inkjet head is determined during this procedure.
After the photolithography process including exposure and
developing, portions of the coated photoresist 124 are removed from
the surface of the nozzle part 120, i.e. the portions where the
hydrophobic layer 141 is to be formed.
[0050] As in (d) of FIG. 5, onto the portions of the nozzle part
120 where the photoresist 124 has been removed, i.e. the portions
where the hydrophobic layer 141 is to be formed, the hydrophobic
layer 141 is joined according to a method apparent to those skilled
in the art. During this procedure, the hydrophobic layer 141 is
formed in a necessary amount on the nozzle for the inkjet head.
[0051] Finally, as in (e) of FIG. 5, the photoresist 124a remaining
on the surface of the nozzle part 120 is removed, to complete the
process of forming the hydrophobic layer 141 on the nozzle for the
inkjet head.
[0052] According to the present invention comprised as above, it is
easy to control the depth of the hydrophobic layer to be uniform,
and the depth to which the hydrophobic layer is deposited may be
controlled even when the back surface of the nozzle has a complex
shape, so that the uniformity and reproduction of the
hydrophobicity-treated nozzles are improved. Also, since the
nozzles treated for hydrophobicity are uniform, the sizes of the
sprayed ink droplets are made uniform, and as the wetting
phenomenon is prevented on the nozzles of an inkjet head due to the
hydrophobicity treatment, the printing performance is improved.
[0053] While the spirit of the invention has been described in
detail with reference to particular embodiments, the embodiments
are for illustrative purposes only and do not limit the invention.
It is to be appreciated that those skilled in the art can change or
modify the embodiments without departing from the scope and spirit
of the invention.
* * * * *