Ink jet recording head having movable member and restricting section for restricting displacement of movable member, and method for manufacturing the same

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ink jet recording head for discharging a liquid from an orifice to form a droplet and a method for manufacturing the same.

2. Related Background Art

As for this type of an ink jet recording head for discharging a liquid from an orifice to form a droplet, an ink jet recording method disclosed in, for example, Japanese Patent Application Laid-Open No. 54-51837 has a different feature from the others in exerting thermal energy on the liquid to thereby obtain motive power for discharging the droplet.

That is, the recording method disclosed in this publication features that a liquid is heated when it receives an action of thermal energy to thereby produce a bubble, which in turn causes a droplet to be discharged from an orifice at the tip of a recording head section, which droplet then sticks to a recording medium to record information.

A recording head applied to this recording method typically comprises a liquid discharge section which includes as components an orifice from which a liquid is discharged and a thermal acting portion section which has a liquid channel to communicate with the orifice and at which thermal energy acts on the liquid to discharge a droplet, an exothermic resistor layer serving as a thermal converter, which is means for generating thermal energy, an overlying protection layer for protecting this exothermic resistor layer from ink, and an underlying layer for accumulating heat.

To improve a printing speed of such an ink jet recording head that obtains motive power for liquid discharge by exerting thermal energy on a liquid, its frequency response may be improved to solve the problem in performance. To improve the frequency response, it is necessary to improve ink refilling performance after droplet discharge. To improve the ink refilling performance, it is in turn necessary to reduce flow resistance over a passage from an ink inlet to an ink orifice.

If the flow resistance is reduced, however, a bubbling pressure escapes toward the ink inlet to result in a drop in discharge speed and so worsen stability, thus deteriorating the discharge performance hence printing. Accordingly, it has been difficult to improve the frequency response while maintaining the discharge performance at a proper level.

Furthermore, to meet a recent market desire for a higher image quality and so to achieve high-resolution printing by use of a small droplet, an ink jet print head needs to be arrayed to provide a high density and also to fly a minute droplet from an orifice.

On the other hand, there has been made such a proposal for providing a movable member, which provides a so-called fluid diode, somewhere in a nozzle channel between the ink inlet and the orifice to thereby improve the frequency response while maintaining proper discharge performance. Such a conventional ink jet recording head, however, may sometimes be subject to flake-off or destruction of the movable member.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention to provide a high-density, high-accuracy, and highly reliable ink jet recording head which solves the above-mentioned problems to thereby enable forming a movable member in the nozzle channel between the ink inlet and the orifice, thus improving the frequency response while keeping proper discharge performance.

To this end, a method of the present invention for manufacturing an ink jet recording head having, on a substrate provided with an exothermic resistor, an ink orifice provided in correspondence to said exothermic resistor and a nozzle channel communicating with said ink orifice, with a movable member formed in said nozzle channel somewhere between said exothermic resistor and an ink inlet for supplying ink into said nozzle channel in such a configuration that a bubble generated in the ink in the nozzle channel by heat generated by said exothermic resistor is utilized to discharge the ink from said ink orifice, comprising the step of:

preparing the substrate provided with said exothermic resistor;

applying such first resin on said substrate as to provide a first mold shape for forming said nozzle channel and said movable member;

forming said first mold shape using said first resin;

applying on said substrate second resin over said first mold shape for forming said nozzle channel and said movable member; and

removing said first mold shape.

By this manufacturing method, the movable member can be molded at the same time as the nozzle mold shape and so can be formed together with the nozzle channel by photolithography at a high density and high accuracy, thus manufacturing a high density, high accuracy ink jet recording head.

Furthermore, to form the movable member, a mask pattern having a width less than a resolution limit of said first resin can be used to form such a portion of said first mold shape as to be used to form said movable member and use the resin applied on the portion later, thus forming the mold shapes of the nozzle channel and the movable member forming portion using the same mask. Accordingly, the nozzle channel and the movable member can be formed at a mask formation accuracy. Furthermore, it is possible to eliminate one patterning step, thus reducing the costs.

Another ink jet recording head of the present invention for utilizing a bubble generated in ink in a nozzle channel when the ink is heated by an exothermic resistor, to discharge the ink from an ink orifice, comprising:

a substrate provided with said exothermic resistor; and

said nozzle channel formed on said substrate, with a movable member formed in said nozzle channel somewhere between said exothermic resistor and an ink inlet for supplying the ink into said nozzle orifice, said movable member having a supporting point thereof on such a wall of said nozzle channel as to be opposed to said substrate and a free end thereof on a surface of said nozzle channel on the side of said substrate and being formed integrally with said wall opposed to said substrate.

In this ink jet recording head, the same material can be used to form the ink channel and the movable member and integrally, so that it is possible to make this ink jet recording head highly reliable and this movable member difficult to flake off or destroy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A

is a schematic cross-sectional view for showing a method for manufacturing an ink jet recording head according to a first embodiment of the present invention,

FIG. 1B

is a cross-sectional view taken along line

1

B—

1

B of

FIG. 1A

,

FIG. 1C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 1A

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention, and

FIG. 1D

is a cross-sectional view taken along line

1

D—

1

D of

FIG. 1C

;

FIG. 2A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 1C

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention,

FIG. 2B

is a cross-sectional view taken along line

2

B—

2

B of

FIG. 2A

,

FIG. 2C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 2A

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention, and

FIG. 2D

is a cross-sectional view taken along line

2

D—

2

D of

FIG. 2C

;

FIG. 3A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 2C

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention,

FIG. 3B

is a cross-sectional view taken along line

3

B—

3

B of

FIG. 3A

,

FIG. 3C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 3A

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention, and

FIG. 3D

is a cross-sectional view taken along line

3

D—

3

D of

FIG. 3C

;

FIG. 4A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 3C

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention,

FIG. 4B

is a cross-sectional view taken along line

4

B—

4

B of

FIG. 4A

,

FIG. 4C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 4A

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention, and

FIG. 4D

is a cross-sectional view taken along line

4

D—

4

D of

FIG. 4C

;

FIG. 5A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 4C

of the method for manufacturing the ink jet recording head according to the first embodiment of the present invention,

FIG. 5B

is a cross-sectional view taken along line

5

B—

5

B of FIG.

5

A.

FIG. 6A

is a schematic cross-sectional view for showing a method for manufacturing an ink jet recording head according to a second embodiment of the present invention,

FIG. 6B

is a cross-sectional view taken along line

6

B—

6

B of

FIG. 6A

,

FIG. 6C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 6A

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention, and

FIG. 6D

is a cross-sectional view taken along line

6

D—

6

D of

FIG. 6C

;

FIG. 7A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 6C

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention,

FIG. 7B

is a cross-sectional view taken along line

7

B—

7

B of

FIG. 7A

,

FIG. 7C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 7A

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention, and

FIG. 7D

is a cross-sectional view taken along line

7

D—

7

D of

FIG. 7C

;

FIG. 8A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 7C

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention,

FIG. 8B

is a cross-sectional view taken along line

8

B—

8

B of

FIG. 8A

,

FIG. 8C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 8A

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention, and

FIG. 8D

is a cross-sectional view taken along line

8

D—

8

D of

FIG. 8C

;

FIG. 9A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 8C

of the method for manufacturing the ink jet recording head according to the second embodiment of the present invention and

FIG. 9B

is a cross-sectional view taken along line

9

B—

9

B of

FIG. 9A

;

FIG. 10

is a plan view for showing a mask pattern used in the step of

FIG. 7A

in the second embodiment of the present invention;

FIG. 11

is a plan view for showing an ink jet recording head according to a variant of the second embodiment of the present invention;

FIG. 12A

is a schematic cross-sectional view for showing a method for manufacturing an ink jet recording head according to a third embodiment of the present invention,

FIG. 12B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 12A

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention,

FIG. 12C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 12B

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention,

FIG. 12D

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 12C

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention, and

FIG. 12E

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 12D

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention;

FIG. 13A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 12E

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention,

FIG. 13B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 13A

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention,

FIG. 13C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 13B

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention, and

FIG. 13D

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 13C

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention;

FIG. 14A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 13D

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention,

FIG. 14B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 14A

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention, and

FIG. 14C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 14B

of the method for manufacturing the ink jet recording head according to the third embodiment of the present invention;

FIG. 15A

is a schematic cross-sectional view for explaining the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention,

FIG. 15B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 15A

of the method for manufacturing the inkier recording head according to the fourth embodiment of the present invention,

FIG. 15C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 15B

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention, and

FIG. 15D

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 15C

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention;

FIG. 16A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 15D

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention,

FIG. 16B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 16A

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention, and

FIG. 16C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 16B

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention;

FIG. 17A

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 16C

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention.

FIG. 17B

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 17A

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention, and

FIG. 17C

is a schematic cross-sectional view for explaining a step which follows the step of

FIG. 17B

of the method for manufacturing the ink jet recording head according to the fourth embodiment of the present invention;

FIG. 18

is a plan view for showing a nozzle section of the ink jet recording head according to the fourth embodiment of the present invention;

FIG. 19A

is a schematic cross-sectional view for showing an ink jet recording head according to a variant of a fourth embodiment of the present invention and

FIG. 19B

is a schematic cross-sectional view, taken along the line of

19

B—

19

B in

FIG. 19A

, for showing a head chip obtained by the variant of the fourth embodiment of the present invention;

FIGS. 20A and 20B

are schematic cross-sectional views for explaining an operation of discharging ink droplets using the ink jet recording head of the present invention;

FIGS. 21A and 21B

are schematic cross-sectional views which follow

FIGS. 20A and 20B

for explaining the operation of discharging ink droplets using the ink jet recording head of the present invention; and

FIG. 22

is a schematic perspective view for showing the ink jet recording head of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe embodiments of the present invention.

FIG. 22

shows a schematic perspective view of an ink jet recording head of the present invention. On a substrate

1

provided with an exothermic resistor

3

and an ink inlet

5

are formed a member

12

which makes up an ink channel and an orifice

7

. Note here that in the following the cross-sectional views, illustrating methods for manufacturing ink jet recording heads in embodiments, of

FIGS. 1A

to

5

B (first embodiment),

FIGS. 6A

to

9

B (second embodiment),

FIGS. 12A

to

14

C (third embodiment), and

FIGS. 15A

to

17

C (fourth embodiment) correspond to the cross-sectional view taken along line A-A′ of FIG.

22

.

First Embodiment

The following will describe a method for manufacturing the ink jet recording head according to the first embodiment of the present invention with reference to

FIGS. 1A

to

5

B.

First, on a silicon substrate

101

are formed a heat accumulation layer

102

and 25-μm×25-μm heaters (exothermic resistors)

103

at 600 dpi, on which is formed a protection layer

104

(FIGS.

1

A and

1

B).

Next, a first mold resist

108

is applied to a thickness of 3 μm (FIGS.

1

C and

1

D).

Next, the first mold resist

108

is patterned into a shape of the nozzle channel by exposure and development (FIGS.

2

A and

2

B).

Next, on thus formed pattern is applied a second mold resist

109

to a thickness of 12 μm (FIGS.

2

C and

2

D).

Next, the second mold resist

109

is patterned into the nozzle channel shape and a movable member shape

111

(5 μm×25 μm) by exposure and development (FIGS.

3

A and

3

B).

Next, a photosensitive epoxy material

112

is applied to form the nozzle channel, the orifice, and the movable member (FIGS.

3

C and

3

D).

Next, an orifice

107

is patterned to have a diameter of 18 μm by exposure and development (FIGS.

4

A and

4

B).

Next, an ink inlet

105

is formed by performing dry-etching on the substrate on its back face side (FIGS.

4

C and

4

D).

Finally, the resists which have served as mold shapes are etched off using an etchant to complete a head chip having the nozzle

106

with the movable member

110

formed therein (FIGS.

5

A and

5

B). Thus, the movable member formed in the nozzle channel has its supporting point on such a wall of the nozzle channel as to be opposite to a surface of the substrate on which the exothermic resistor is mounted and its free end on this side of the substrate.

Then, electrical mounting is carried out for feeding power to electrify the heater and tube in order to supply ink, thus completing the ink jet recording head.

Thus completed head has a high frequency response and good discharge performance. It is thus possible to print information speedily and satisfactorily.

Furthermore, since the movable member is patterned by photolithography, it can be formed highly accurately and also arranged with respect to the heater, the nozzle, and the orifice at a high accuracy. Accordingly, it is possible to sufficiently meet the requirements for the future smaller droplet and higher density.

Furthermore, the head can be manufactured integrally with the epoxy material of the nozzle and the orifice and so is not so subject to flake-off or destruction in long-term services nor to solving out or swelling of the epoxy material if it is selected to have ink resisting properties.

It is thus possible to provide a highly reliable head.

Second Embodiment

The following will describe another method for manufacturing an ink jet recording head according to the second embodiment of the present invention with reference to

FIGS. 6A

to

9

B.

First, as in the case of the first embodiment, a substrate provided with heaters on which 25-μm by 25-μm heaters are arrayed is made (FIGS.

6

A and

6

B).

Next, a photo-resist

208

which provides a mold shape is applied to a thickness of 20 μm (FIGS.

6

C and

6

D).

Next, a pattern is formed through exposure and development by using a mask which has a mask pattern of a nozzle channel shape and a movable member shape such as shown in

FIG. 10

(FIGS.

7

A and

7

B).

The photo-resist

208

used in the present embodiment has a resolution of 4 μm when it is applied to a thickness of 20 μm, so that the mask used in this patterning is selected so that its width W at a portion that corresponds to a thickness of a movable member in the mask pattern may be 2 μm less than the resolution limit.

Such a mask as to have the width less than the resolution limit is used in formation to result in the resist being patterned halfway as shown in

FIGS. 7A and 7B

. The pattern, therefore, does not reach the substrate and so can function as a mold shape of the movable member.

Next, a photo-sensitive epoxy is applied to form a nozzle channel, an orifice, and the movable member (FIGS.

7

C and

7

D).

Next, the orifice is patterned to have a diameter of 18 μm by exposure and development (FIGS.

8

A and

8

B).

Next, dry-etching is conducted on the substrate on its back face side to form an ink inlet (FIGS.

8

C and

8

D).

Finally, the resist which has served as the mold shape is etched off using an etchant to complete the substrate provided with a nozzle (FIGS.

9

A and

9

B).

Then, a tube (not shown) for supplying ink and a printed wiring board (not shown) for feeding power to electrify the heaters are connected to the substrate, thus completing the ink jet recording head.

Thus completed head has a high frequency response and good discharge performance. It is thus possible to print information speedily and satisfactorily.

In addition to the effects of the first embodiments, the present embodiment can eliminate one of the application, exposure, and development steps for the mold resist, thus reducing the costs for manufacturing.

Furthermore, the nozzle channel and the movable member can be formed using the same mask, further improving accuracy in alignment.

Furthermore, the movable member thus formed in the nozzle channel is formed integrally with the wall of the nozzle channel as in the case of the first embodiment and also has such a construction that its supporting-point side thickness t

1

is larger than its free-end side thickness t

2

, thus making itself less subject to flake-off or destruction. It is thus possible to provide more highly reliable ink jet recording head.

Furthermore, as shown in

FIG. 11

, if the nozzle is patterned to form its channel in such a manner that part of the nozzle channel between the movable member and the inlet may be narrowed than the width of the movable member to thereby restrict the movable member from being displaced toward the inlet, the bubbling pressure can be suppressed more from escaping toward the inlet, thus manufacturing the head with even higher discharge performance without increasing the required steps in manufacture.

Third Embodiment

The following will describe a further method for manufacturing an ink jet recording head (ink jet print head) according to the third embodiment of the present invention with reference to

FIGS. 12A

to

14

C.

First, as shown in

FIG. 12A

, for example, a silicon chip is mounted thereon by patterning etc. with a plurality of heaters

303

and a predetermined wiring (not shown) for feeding a voltage to these heaters

303

, thus forming an element substrate

301

. Then, as shown in

FIG. 12B

, on said element substrate

301

is applied to a thickness of about 5.0 μm a transparent negative-type resin layer

313

having the same composition as an orifice substrate

312

in order to form a projecting barrier

313

′ which restricts said movable member

310

from being displaced toward an inlet

305

.

Then, as shown in

FIG. 12C

, UV rays are used to form the projecting pattern (projecting barrier)

313

′. Next, as shown in

FIGS. 12D and 12E

, on said substrate

301

are applied an underlying resin layer

308

and an overlying resin layer

309

by spin coating consecutively. These underlying and overlying resin layers

308

and

309

are made of resin that can be resolved because its intra-molecular bond is destroyed when it is irradiated with Deep-UV rays (hereinafter called DUV rays), which are ultra-violet rays having a wavelength of 330 nm or less. Furthermore, by using resin which exhibits cross-linking properties due to dehydration/condensation as the material of the underlying resin layer, interactive melting of the underlying and overlying resin layers

308

and

309

can be prevented when the overlying resin layer

309

is applied by spin coating. As the material of the underlying resin layer

308

, a solution has been used which is obtained, for example, by resolving, in a cyclohexanone solvent, binary copolymer (P(MMA-MAA)=90:10) polymerized by polymerizing radicals of methacrylic acid methyl (MMA) and methacrylic acid (MAA). As the material of the overlying resin layer

309

, on the other hand, a solution has been used which is obtained, for example, by resolving poly-methyl isopropenyl ketone (PMIPK) in a cyclohexanone solvent. The binary copolymer (P(MMA-MAA)) used as the material of the underlying resin layer can be heated at a temperature of 180-200° C. for 30 minutes to two hours to provide a harder cross-linking film owing to the dehydration/condensation reaction. Note here that although this cross-linking film is insoluble in a solvent, when irradiated with an electron beam such as DUV rays it decomposes and its mole molecular weight is decreased, so that only a portion thereof irradiated by the electron beam becomes soluble in the solvent.

Then, as shown in

FIG. 13A

, a filter which blocks DUV rays having a wavelength of less than 260 nm is mounted to an exposing apparatus for applying DUV rays to then use wavelength selecting means which transmits only such rays as to have a wavelength of 260 nm or more to thereby apply Near-UV rays (hereinafter called NUV rays) having a wavelength nearly equal to 260 to 330 nm to the overlying resin layer

309

in order to expose and develop it, thus forming a desired nozzle pattern

309

′ by use of the overlying resin layer

309

. Since the ratio in photosensitivity to NUV rays with a wavelength of about 260 to 330 nm is about 40:1 between the overlying and underlying resin layers

309

and

308

, the underlying resin layer

308

is not exposed to the rays, so that the overlying resin layer: P(MMA-MAA) is not decomposed. Furthermore, the underlying resin layer

308

is made of a thermal cross-linkage film and so not resolved in a developer in the development of the overlying resin layer.

Then, as shown in

FIG. 13B

, the above-mentioned exposing apparatus is used to apply DUV rays with a wavelength of 210 to 330 nm to expose and develop the underlying resin layer, thus forming a desired nozzle pattern

308

′ by use of the underlying resin layer

308

. The P(MMA-MAA) material used to form the underlying resin layer

308

has a high resolution and so can be formed so as to have a trench construction with a side wall inclination angle of 0 to 5° even if it is formed to a thickness of 5 to 20 μm or so.

Then, on the overlying and underlying resin layers

309

and

308

which have thus been made resolvable because the intra-molecular cross-linkage bond is destroyed by DUV rays with the nozzle patterns

308

′ and

309

′ formed thereon, a transparent covering resin layer

312

is applied which provides the orifice substrate

12

as shown in FIG.

13

C.

Then, as shown in

FIG. 13D

, the exposing apparatus is used to apply UV rays to the covering resin layer

312

to expose and develop a portion that corresponds to an orifice

307

in order to etch it off, thus forming the orifice substrate. Preferably an inclination angle of a side wall of the orifice formed in this orifice substrate is nearly 0° with respect to the plane perpendicular to the main surface of said element substrate. Furthermore, as far as the inclination angle is 0 to 10°, the droplet discharge properties are not so affected adversely.

Then, as shown in

FIG. 14A

, to protect the right side of the orifice plate in chemical etching, an organic resin film

314

is applied thereon. Then, as shown in

FIG. 14B

, chemical etching is conducted on the back side of the element substrate

301

to thereby form the inlet

305

therein. This chemical etching is of anisotropic processing by use of, for example, a strong alkali solution (KOH, NaOH, TMAH).

Then, as shown in

FIG. 14C

, DUV rays with a wavelength of 300 nm or less are applied from the main surface side of the element substrate

301

through the covering resin layer

312

to thereby solve out the overlying and underlying resin layers

309

and

308

, which are the nozzle mold shape positioned between the element substrate

301

and the orifice substrate

312

.

The movable member

310

, therefore, is formed between the orifice

307

and the inlet

305

and also between the heaters

303

and the inlet

305

in the supplying passage (nozzle channel) communicating the orifice

307

and the inlet

305

with each other, thus giving a chip provided with a nozzle channel

306

with a projecting barrier formed between the movable member

310

and the inlet

305

for restricting this movable member from being displaced toward the inlet. By electrically interconnecting this chip and a wiring board (not shown) which drives the heaters

303

, the recording head is obtained.

Note here that by this method for manufacturing the recording head, furthermore, an overlying resin layer

41

and an underlying resin layer

42

made resolvable because DUV rays have been applied to destroy the intra-molecular cross-linkage bond can be stacked in construction with respect to the width direction of the element substrate

11

, thus providing such a control section in the nozzle

27

as to have at least three steps. For example, even over the overlying resin layer can be formed a resin material which is photo-sensitive to lights having a wavelength of 400 nm or more, thus multi-stage nozzle construction.

Fourth Embodiment

The following will describe in detail a still further method for manufacturing the ink jet print head according to the fourth embodiment of the present invention with reference to

FIGS. 15A

to

17

C.

First, as shown in

FIG. 15A

, a silicon chip is mounted thereon by patterning etc. with a plurality of electrical thermal converting elements (heaters)

403

and a wiring (not shown) necessary to drive these heaters, thus providing a substrate

401

.

Then, as shown in

FIGS. 15B and 15C

, the substrate

401

is irradiated with DUV rays (ultraviolet rays having a wavelength of 300 nm or less) so that its intra-molecular cross-linkage bond may be destroyed and subsequently has resolvable resin layers

408

and

409

consecutively applied thereon by spin coating. In this step, thermal cross-linking type resin is used as a material of the underlying resin layer

408

to thus prevent interactive melting of the underlying and overlying resin layers when the overlying resin layer

409

is applied by spin coating. In this case, as a material of the underlying resin layer

408

is used a liquid obtained by resolving P(MMA-MAC=90:10) in a cyclohexanone solvent. As a material of the overlying resin layer, on the other hand is used a liquid obtained by resolving PMIPK in a cyclohexanone solvent. Then, an exposing apparatus (PLA521 made by Canon) using DUV rays is mounted with CM290 in order to use only the DUV rays having a wavelength of nearly 290 nm in the exposure and development of the overlying resin layer

409

, thus forming a nozzle pattern

409

′ such as shown in FIG.

15

D. In this case, since the ratio in photosensitivity to the DUV rays with a wavelength of nearly 290 nm is about 50:1 or more between the overlying resin layer

409

and the underlying resin layer

408

, the underlying resin layer is not exposed to the rays to be patterned. Next, the same exposing apparatus is mounted with CM250 to use only the DUV rays with a wavelength of nearly 250 nm in the exposure and development of the underlying resin layer, thus forming a nozzle pattern such as shown in FIG.

16

A. Subsequently, on the resin layers

408

and

409

on which such nozzle patterns are formed and which have thus been made resolvable owing to the destruction of the intra-molecular cross-linkage bond is formed a covering resin layer

412

(FIG.

16

B),such a portion of which as to correspond to an orifice

407

is exposed and developed using an exposing apparatus (MPA-600 made by Canon) using UV rays and removed (FIG.

16

C).

Next, as shown in

FIG. 17A

, an organic resin film

414

is applied to protect the orifice face side in chemical etching. Then, as shown in

FIGS. 17B and 17C

, for example, the substrate

401

is etched chemically on its back side to form the inlet

3

. More specifically, a strong alkali solution (KOH, NaOH, TMAH) is used in anisotropic etching to thereby form an inlet

405

. Finally, DUV rays (ultra-violet rays with a wavelength of 300 nm or less) are applied from the surface of the element substrate

401

through the covering resin layer

412

to thereby solve out the resin layers

408

′ and

409

′, which are the nozzle patterns. It is thus possible to give an ink jet head chip provided with the orifice

407

, the inlet

405

, a step-shaped nozzle

406

communicating with these, a movable member

410

between the electrical thermal converting element

403

in the nozzle

406

and the inlet

405

, and a control section

412

′ which restricts the movable member from being displaced toward the inlet. By electrically connecting this chip with a wiring board which drives the electrical thermal converting element, the ink jet recording head of the present invention can be obtained.

FIG. 18

is a plan view of the nozzle portion of the above-mentioned ink jet recording head (

FIG. 17C

corresponds to a cross-sectional view taken along line

17

C—

17

C of FIG.

18

). The above-mentioned movable member

410

is formed near projecting part

412

′ of a side wall of the nozzle channel

406

serving as a stopper (barrier) which can restrict the movable member

410

from being displaced toward the ink inlet

405

in order to mostly close a portion extending from the movable member

410

to the orifice when a bubble is generated over the surfaces of the heaters. Preferably this barrier is small in size in order not to interfere with the flowing of ink from the inlet toward the orifice as little as possible when it is refilled. Furthermore, there is a minute gap that can be given by a photolithographic process between the movable member and the nozzle wall. Preferably this gap is as small in size as possible so long as it permits the movable member to be displaced.

Furthermore, as in the case of an ink jet recording bead shown in

FIGS. 19A and 19B

, not only by projecting part

512

′ of a side wall of a nozzle channel

506

and by forming between a movable member

510

and an ink inlet

505

as in the ease of the present embodiment but also by forming a projecting barrier

513

′ on the substrate as in the case of the third embodiment, it is possible to further suppress the flowing of the ink toward the ink inlet

505

using a movable member

510

more effectively when a bubble is growing, further improving the discharge performance.

The following will briefly describe the operations of thus manufactured ink jet recording head (liquid discharge head) of the present invention with reference to

FIGS. 20A

,

20

B,

21

A and

21

B.

First, as shown in

FIG. 20A

, an orifice channel extending from the heaters to the orifice and a nozzle

606

extending from the heaters to the ink inlet are combined to form art L-shape. In the nozzle, the movable member is arranged perpendicularly to a surface of the substrate provided with the heaters on the side of the nozzle. As shown in

FIG. 20B

, on the other hand, when a bubble

615

is generated by the heaters, a pressure wave occurs simultaneously and ink starts to flow, to cause a movable member

610

to be inclined slightly toward an ink inlet

605

, so that the nozzle is kept in a roughly closed state over a portion thereof from the orifice to the movable member, by the movable member, a projecting barrier

613

′ formed on the HB (substrate), and a stopper-shaped structure

612

′ formed behind the movable member. It is thus possible to focus the pressure over the heaters mostly on the side of the orifice in order to thereby fly a discharged ink droplet effectively. Note here that preferably a minute gap which is present between The movable member and a projecting barrier

613

′ is as small in size as possible in order to provide the above-mentioned roughly closed state. Furthermore, there is another minute gap between the movable member

610

and the side wall of the nozzle

606

.

Now, as shown in

FIG. 21A

, since the nozzle is roughly closed by the movable member

610

, the projecting barrier

613

′, and the stopper-shaped structure

612

′, the bubble grows larger toward the orifice to thereby enable flying the ink droplet from the orifice in a more stable manner and more effectively. As shown in

FIG. 21B

, subsequently, when the bubble starts disappearing over the heaters, the movable member

610

starts to be displaced toward the orifice

607

. Then, the movable member

610

is displaced greatly toward the orifice. In this case, a displacement of the movable member toward the orifice is larger than that thereof toward the ink inlet at the time of bubble growing. The ink is thus refilled speedily into a plurality of the ink nozzles

606

from the ink inlet

605

. Note here that when the bubble is generated the ink is inhibited from flowing toward the inlet

605

by the movable member

610

, the projecting barrier

613

′ formed on the HB (substrate)

601

, and the stopper structure

612

′ formed behind the movable member, so that the quantity of the ink refilled into the nozzles

606

can be reduced to a minimum nearly equal to the volume of the ink flown (discharged).

Number	Date	Country	Kind
2001-243299	Aug 2001	JP
2002-216166	Jul 2002	JP

Number	Name	Date	Kind
5478606	Ohkuma et al.	Dec 1995	A
5872582	Pan	Feb 1999	A
5943074	Kashino et al.	Aug 1999	A
6095640	Ishinaga et al.	Aug 2000	A
6113224	Sugama et al.	Sep 2000	A
6164763	Sugama et al.	Dec 2000	A
6180018	Miyagawa et al.	Jan 2001	B1
6196667	Hiroki et al.	Mar 2001	B1
6199972	Ishinaga et al.	Mar 2001	B1
6206505	Yoshihira et al.	Mar 2001	B1
6286940	Sugiyama et al.	Sep 2001	B1
6374482	Mihara et al.	Apr 2002	B1
6378992	Kudo et al.	Apr 2002	B2
6378993	Ozaki et al.	Apr 2002	B1
6386686	Kubota et al.	May 2002	B1
6386832	Taneya et al.	May 2002	B1
6390604	Kashino et al.	May 2002	B2
6402302	Ozaki et al.	Jun 2002	B1
6409296	Misumi et al.	Jun 2002	B1
6409317	Shimazu et al.	Jun 2002	B1
6435661	Inoue et al.	Aug 2002	B1
6435670	Inoue et al.	Aug 2002	B1
6439700	Ishinaga et al.	Aug 2002	B1
6450776	Taneya et al.	Sep 2002	B1
6455112	Ohkuma et al.	Sep 2002	B1

Ink jet recording head having movable member and restricting section for restricting displacement of movable member, and method for manufacturing the same

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (2)

US Referenced Citations (25)

Foreign Referenced Citations (1)