Information
-
Patent Grant
-
6199980
-
Patent Number
6,199,980
-
Date Filed
Monday, November 1, 199924 years ago
-
Date Issued
Tuesday, March 13, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 347 93
- 347 92
- 210 498
- 210 171
- 096 204
- 096 206
- 096 220
- 096 219
-
International Classifications
-
Abstract
An efficient fluid filtering device is provided for filtering unwanted contaminants from flowing fluid, such as ink flowing into an ink jet printhead. The efficient fluid filtering device includes a generally flat member having a first side and a second side, and a series of fluid flow holes formed through the flat member from the first side to the second side. Importantly, the efficient fluid filtering device also has a series of pillar members, including pillar members defining a trough portion around each fluid flow hole. The pillar members and the trough portions are arranged around each hole so as to efficiently prevent bubbles and contaminants in flowing fluid from impeding fluid flow from the first side through to the second side.
Description
BACKGROUND OF THE INVENTION
In the new and emerging area of microfluidics, microfluidic carrying devices and their components are small, typically in the range of 500 microns down to as small as 1 micron and possibly even smaller. Such microfluidic devices pose difficulties with regards to preventing fluid path blockage within the microscopic componentry, and especially when the particular microscopic componentry is connected to macroscopic sources of fluid. Yet such microfluidic devices are important in a wide range of applications that include drug delivery, analytical chemistry, microchemical reactors and synthesis, genetic engineering, and marking technologies including a range of ink jet technologies, such as thermal ink jet.
The present invention relates to microfluidic devices in general and in particular to an efficient fluid filtering device for ink jet printers and, more particularly, to a thermal ink jet printhead including such an efficient fluid filtering device.
A typical thermally actuated drop-on-demand ink jet printing system uses thermal energy pulses to produce vapor bubbles in an ink-filled channel that expels droplets from the channel orifices of the printing system's printhead. Such printheads have one or more ink-filled channels communicating at one end with a relatively small ink supply chamber (or reservoir) and having an orifice at the opposite end, also referred to as the nozzle. A thermal energy generator, usually a resistor, is located within the channels near the nozzle at a predetermined distance upstream therefrom. The resistors are individually addressed with a current pulse to momentarily vaporize the ink and form a bubble which expels an ink droplet. A meniscus is formed at each nozzle under a slight negative pressure to prevent ink from weeping therefrom.
Some of these thermal ink jet printheads are formed by mating two silicon substrates. One substrate contains an array of heater elements and associated electronics (and is thus referred to as a heater plate), while the second substrate is a fluid directing portion containing a plurality of nozzle-defining channels and an ink inlet for providing ink from a source to the channels (thus, this substrate is referred to as a channel plate). The channel plate is typically fabricated by orientation dependent etching methods.
The dimensions of ink inlets to the die modules, or substrates, are much larger than the ink channels; hence, it is desirable to provide a filtering mechanism for filtering the ink at some point along the ink flow path from the ink manifold or manifold source to the ink channel to prevent blockage of the channels by particles carried in the ink. Even though some particles of a certain size do not completely block the channels, they can adversely affect directionality of a droplet expelled from these printheads. Any filtering technique should also minimize air entrapment in the ink flow path.
Various techniques are disclosed for example, in U.S. Pat. Nos. 5,154,815, and 5,204,690 for forming filters that are integral to the printhead using patterned etch resistant masks. This technique has the disadvantage of flow restriction due to the proximity to single channels and poor yields due to defects near single channels. Further, U.S. Pat. No. 4,864,329 to Kneezel et al. for example, discloses a thermal ink jet printhead having a flat filter placed over the inlet thereof by a fabrication process which laminates a wafer size filter to the aligned and bonded wafers containing a plurality of printheads.
The individual printheads are obtained by a sectioning operation, which cuts through the two or more bonded wafers and the filter. The filter may be a woven mesh screen or preferably a nickel electroformed screen with predetermined pore size. Since the filter covers one entire side of the printhead, a relatively large contact area prevents delamination and enables convenient leak-free sealing. In general, electroformed screen filters which have pore sizes small enough to filter out particles of interest, result in filters which are very thin and subject to breakage during handling or wash steps. Also, the preferred nickel embodiment is not compatible with certain inks resulting in filter corrosion. Finally, the choice of materials is limited when using this technique. Woven mesh screens are difficult to seal reliably against both the silicon ink inlet and the corresponding opening in the ink manifold. Plating with metals such as gold to protect against corrosion is costly, and in all cases, conventional filters ordinarily suffer from blockage by particles larger than the pore size, and by air bubbles.
Conventional filters used for thermal ink jet printheads help keep the jetting nozzles and channels free of clogs caused by dirt and air bubbles carried into the printhead from upstream sources such as from the ink supply cartridge. One common failing of all filters is that dirt can accumulate on the filter surface causing restricted fluid flow. Another kind of blockage is when an air bubble rests on the filter surface thereby covering a large group of fluid flow holes preventing any fluid from passing through that region of the filter.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an efficient fluid filtering device is provided for filtering unwanted contaminants from flowing fluid, such as ink flowing into an ink jet printhead. The efficient fluid filtering device includes a generally flat member having a first side and a second side, and a series of fluid flow holes formed through the flat member from the first side to the second side. Importantly, the efficient fluid filtering device also has a series of pillar members, including pillar members defining a trough portion around each fluid flow hole. The pillar members and the trough portions are arranged around each hole so as to efficiently prevent bubbles and contaminants in flowing fluid from impeding fluid flow from the first side through to the second side.
BRIEF DESCRIPTION OF THE DRAWINGS
In the detailed description of the invention presented below, reference is made to the drawings, in which:
FIG. 1
is a schematic isometric view of an ink jet printhead module with an efficient filtering device of the present invention bonded to the ink inlet.
FIG. 2
is a cross-sectional view of the printhead of
FIG. 1
further including an ink manifold in fluid connection with the ink inlet;
FIG. 3
is a top view illustration of a first side of an exemplary pattern of fluid flow holes and blocking pillars of the efficient filtering device of
FIG. 1
;
FIGS. 4-6
respectively show vertical cross-sections of a first embodiment of the filtering device of
FIG. 3
taken along view-planes
4
—
4
,
5
—
5
and
6
—
6
of
FIG. 3
showing fluid flow holes and blocking pillars in accordance with the present invention; and
FIG. 7
is a vertical section of a second embodiment of an exemplary pattern of fluid flow holes and blocking pillars of the efficient filtering device of the present invention.
DESCRIPTION OF THE INVENTION
While the present invention will be described in connection with preferred embodiments thereof, it will be understood that it is not intended to limit the invention to these embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
Referring first to
FIGS. 1 and 2
, a thermal ink jet printhead
10
fabricated according to the teachings of the present invention is shown comprising a heater plate
16
shown in dashed line, and a channel plate
12
including a laser-ablated efficient filtering device of the present invention, shown generally as
14
. A patterned thick film layer
18
is shown in dashed line having a material such as, for example, Riston®, Vacrel®, or polyimide, and is sandwiched between the channel plate
12
and the heater plate
16
. The thick film layer
18
is etched to remove material above each heating element
34
, thus placing the heating elements in pits
26
. Material is removed between the closed ends
21
of ink channels
20
and a reservoir
24
, thus forming a trench
38
that places the channels
20
into fluid communication with the reservoir
24
. For illustration purposes, droplets
13
are shown following trajectories
15
after ejection from the nozzles
27
in front face
29
of the printhead.
Referring in particular to
FIG. 1
, channel plate
12
is permanently bonded to heater plate
16
or to the patterned thick film layer
18
optionally deposited over the heating elements and addressing electrodes on the top surface
19
of the heater plate and patterned. The channel plate
12
and the heater plate
16
are both typically silicon. The illustrated embodiment of the present invention is described for an edge-shooter type printhead, but could readily be used for a roofshooter configured printhead (not shown), wherein the ink inlet is in the heater plate, so that the integral filter of the present invention could be fabricated in a similar manner.
Channel plate
12
of
FIG. 1
contains an etched recess defined by walls
28
, shown in dashed line, in one surface which, when mated to the heater plate
16
, forms the ink reservoir
24
. A plurality of identical parallel grooves
20
, shown in dashed line and having triangular cross sections, are etched (using orientation dependent etching techniques) in the same surface of the channel plate with one of the ends thereof penetrating the front face
29
. The other closed ends
21
(
FIG. 2
) of the grooves are adjacent to the recess defined by walls
28
. When the channel plate and heater plate are mated and diced, the groove penetrations through front face
29
produce orifices or nozzles
27
. Grooves
20
also serve as ink channels which contact the reservoir
24
(via trench
38
) with the nozzles. Alternately, the ink channels may be formed in the polyimide by photopatterning or by other etching process on the channel wafer. The open bottom of the reservoir in the channel plate, shown in
FIG. 2
, forms an ink inlet
25
and provides means for maintaining a supply of ink in the reservoir through a manifold from an ink supply source in an ink cartridge
22
, partially shown in FIG.
2
. The cartridge manifold is sealed to the ink inlet by adhesive layer
23
.
Referring now to
FIGS. 1-6
, the efficient filtering device
14
of the present invention preferably is fabricated by laser-ablating a thick film
17
of polymer material to form fluid flow side areas on a first side
42
, a series of blocking pillars
50
, and a series of fluid flow holes
46
therethrough. The resulting filtering device is then adhesively bonded to the first or fill hole side of channel plate
12
. As shown, the efficient filtering device
14
is mounted across a fluid flow inlet, such as the ink inlet
25
, for efficiently filtering such flowing fluid, by blocking and preventing air bubbles and contaminants from flowing with ink through the ink inlet into the channels and nozzles
27
of the printhead. The filtering device
14
preferably is mounted with the contoured side, or first side
42
, facing the outside of the die or printhead, so as to prevent clogging or other blockage of the filter. In a preferred method of fabrication, an array of filters or filtering devices
14
is created on a single polymer film
17
. The array of filters thus corresponds to die or printhead sites on the silicon channel wafer. The film is aligned and bonded to the silicon wafer. Subsequently, dicing of the wafer with attached filter or filtering device array yields individual die that have filters covering each inlet.
Still referring to
FIGS. 1-6
, as illustrated the efficient filtering device
14
includes the generally flat member
51
that is laser-ablated from a thick film of polymer material, and after such ablation having a first side
42
and a second side
44
. The thick film of polymer material, in a preferred embodiment, is polyimide such as Kapton or Upilex, or any of other polymer films which are selected for chemical compatibility with the inks to be used. Examples of other films include polyester, polysulfone, polyetheretherketone, polyphenelyene sulfide, polyethersulfone.
The generally flat member
51
includes the series or pattern of fluid flow holes
46
formed through the flat member
51
from the first side
42
to the second side
44
for filtering ink flowing into the ink inlet
25
(FIG.
1
), and hence into the channels and nozzles
27
. The generally flat member
51
also includes a series or pattern of pillar members
50
, including pillar members surrounding each fluid flow hole
46
(FIGS.
3
and
4
). The pillar members surrounding each fluid flow hole define a trough portion
54
around each fluid flow hole
46
, and each trough portion
54
has beveled walls
52
and a base
56
. As shown (FIGS.
4
and
6
), each fluid flow hole
46
is formed through the base
56
of a trough portion. Each trough portion
54
as shown has a generally circular top surface, and is formed between pillar members
50
, and above at least a fluid flow hole
46
.
Conventional filters used for thermal ink jet printheads help keep the jetting nozzles and channels free of clogs caused by dirt and air bubbles carried into the printhead from upstream sources such as from the ink supply cartridge
22
. One common failing of all filters is that dirt can accumulate on the filter or filtering device side causing restricted fluid flow. Another kind of blockage is when an air bubble rests on the filter or filtering device side thereby covering a large group of fluid flow holes preventing any fluid from passing through that region of the filter.
As pointed out above, the filtering device
14
is created from the generally flat film by laser ablation. The ablation process creates holes through the film to provide the filtering action and in the present invention also creates other side relief features (pillar members
50
, troughs
54
, and beveled hole-facing surfaces
52
of pillar members
50
) that allow lateral ink flow along the filter or filtering device to permit ink to reach a through-hole
46
in the filter or filtering device in the presence of particles or bubbles. Accordingly, the generally flat member
51
of the efficient filtering device
14
of the present invention importantly includes a series of blocking pillar members
50
that are the remaining portions (after ablation) of the initial top side
42
of the filter or filtering device film prior to the laser ablation of the through holes
46
and side contours. The remaining pillar members
50
serve the purpose of preventing air bubbles and contaminants from reaching and potentially blocking some of the series of fluid flow holes
46
. The lateral fluid flow path created by the pillars extend the useful life of the filter and thus extend the useful life of the printhead.
The use of laser ablation to create filters in polymeric materials is described for example in U.S. patent application (Ser. No. 08/926,692 to Markham, et al., relevant portions of which are incorporated herein by reference. As disclosed therein, the efficient filtering device
14
can be fabricated by laser ablation. To do so for example, output beams can be generated by an excimer laser device and directed to an appropriate mask having a plurality of holes therethrough. Laser radiation passes through the holes in the mask. The mask is imaged onto the film substrate. Laser ablation of the polymer film occurs if the illumination light from the excimer or other laser is at sufficiently high energy density, depending on the material but generally >200 mJ/cm
2
. In the present invention, laser light not only illuminates the hole pattern on the mask but illuminates to a lesser degree the polymer between holes, thereby ablating at a slower rate material between holes to form the lateral flow channels. Thus the laser ablation process forms the series of tapered fluid flow holes
46
, and the troughs
54
and hence the beveled sides
52
of pillar members
50
, where the top of the pillars
50
remain as unablated areas on the first side of the film member
17
being ablated.
The filters are created on the film so as to match the ink inlets created over an entire channel wafer. The film is bonded to the wafer with the filters aligned over the ink inlets individually. The current invention differs from the above in that the current invention describes a 3-dimensionally contoured filter surface containing pillars, posts or ridges
50
,
50
, that hold particles of bubbles away from the filter holes
46
. The pillars
50
permit fluid to flow laterally on at least one side of the filter until the fluid can flow through the filter holes
46
. This lateral flow capability due to the structured filter surface reduces the tendency of a filter to be clogged.
Referring now to
FIGS. 3-7
, the series of fluid flow holes
46
can be formed into a pattern of spaced apart linear arrays (as shown
FIG. 3
) such that each fluid flow hole
46
forms part of a lateral array, as well as part of a diagonal array. As such, the series of pillar members
50
are then formed interspersed between adjacent fluid flow holes
46
. The net result is each fluid flow hole
46
has a pillar member
50
(
FIG. 3
) on each side thereof. As shown in
FIG. 4
, each pillar member
50
of the series of pillar members includes a hole-facing side
52
including a beveled portion for facilitating and enhancing the trapping of air bubbles away from the adjacent fluid flow holes. Further, as shown in
FIG. 3
, each pillar member
50
is formed as the area outside where 3 or more trough circles
54
intersect. Each pillar or pillar member
50
has a nearly rectangular base wherein the sides of each rectangular base are formed angularly to a line through a lateral array of fluid flow holes, thereby narrowing the spacings or flow passages
53
between adjacent pillar members
50
, and increasing the contaminant blocking capability of the pillar members
50
.
In accordance with a second embodiment of the fluid filtering device of the present invention as shown in
FIG. 7
, a far thicker film
17
′ can be ablated on both sides
42
,
44
to form a thicker, generally flat member
51
′. As such, pillar members
50
will be fabricated on the first side
42
, and pillar members
50
′ on the second side
44
, as shown in
FIG. 7
, so that the fluid flow holes
46
are located approximately midway through the thickness of the generally flat member
51
′. This structure is useful in applications where relative to the direction of fluid flow, bubbles generated downstream from or on the second or downstream side
44
of the fluid flow holes
46
, (as fluid levels change on such downstream side
44
) can migrate backwards or upwards to the fluid flow holes, and there restrict flow through the fluid holes.
In this embodiment, the generally flat member
51
′ similarly includes a series or pattern of the pillar members
50
′, including pillar members surrounding each fluid flow hole
46
. The pillar members
50
′ surrounding each fluid flow hole
46
define a trough portion
54
′ around each fluid flow hole
46
, and each trough portion
54
′ has beveled walls
52
′ and a base
56
′. As shown (FIG.
7
), each fluid flow hole
46
is formed through the base
56
′ of a trough portion. The pillar members
50
′ advantageously act to effectively prevent air bubbles from backing up and undesirably sealing off the fluid flow holes
46
from such downstream side.
Referring still to
FIGS. 1-7
, the size of the efficient filtering device
14
must be large enough to provide an adequate seal across ink inlet
25
with enough edge side to allow use of adhesive layer
23
for bonding the edges. Additional filters are formed by a step and repeat process to correspond with the multiple die sites on the heater and channel wafers. In a first preferred embodiment (FIG.
3
), the thickness of film member
17
before ablation, (and hence a height of each pillar member) is greater than 20 microns, and fluid flow holes
46
can be in the range of 1-100 microns diameter with preferred diameters of 5-30 microns for ink jet devices operating at 600 spots per inch. In a second preferred embodiment (FIG.
7
), the thickness of film member
17
′ before ablation, (and hence a total height of the pillar members
50
and
50
′) is greater than 40 microns. The fluid flow holes
46
which are in the range of 1-100 microns diameter are preferably formed only from the first side
42
in order to maintain a desired taper. The taper angle into the holes
46
depends on process conditions and can be within about a 0.5-10° with a typical taper of 5 degrees. (The taper is exaggerated in the Figures only for descriptive purposes).
Although the examples shown in the figures correspond to die module types in which the channels and ink inlets are formed by orientation dependent etching, other fabrication methods for the fluidic pathways are compatible with the laser ablated filter or filtering device described herein. And, although the exemplary laser ablation is accomplished through a mask, alternate light transmitting systems may be used such as, for example, diffraction optics lo displays or a microlens elements. It should be understood that the efficient filtering device
14
of the present invention can be applied to thermal as well as piezoelectric or other electromechanical ink jet transducers and roof shooter geometries as well as side shooter geometries.
As described above, an ink jet fluid filter or filtering device such as the efficient filtering device
14
,
14
′ (
FIG. 7
) of the present invention can be fabricated by laser ablating fluid flow holes
46
into a plastic or polymer film member
17
,
17
′. The ablated filter or filtering device can then be placed into the fluid flow path between an ink supply cartridge
22
and the channels
20
and nozzles
27
of an ink jet transducer or printhead so that ink can pass through the filtering device while dirt and air bubbles are trapped or blocked and prevented from reaching the fluid flow holes. As shown, the ablated film filtering device
14
,
14
′ includes a series of pillar members
50
,
50
′ around fluid flow or filter or filtering device holes
46
. The pillar members
50
,
50
′ function as the walls of ink flow channels and so hold most dirt particles and air bubbles away from direct contact with the fluid flow holes, while flowing liquid can find a meandering pathway around the pillar member obstructions and still reach and pass through the filter or filtering device holes. The pillar member filter or filtering device structure as such is generated by using a thicker than conventional film
17
,
17
′, in conjunction with laser ablated holes of a controlled spacing and bevel.
The fluid flow holes
46
are easily fabricated by laser ablation. The pillar members
50
,
50
′ can be fabricated at the same time as the holes under certain conditions described below. Each hole is tapered so that the hole at the top (side
42
) of the film
17
is much larger than the hole at the bottom (side
44
) of the film. If neighboring holes at the top of the film eclipse each other, then a pillar
50
is formed as shown in FIG.
3
. The pillar structure can alternatively be generated by photopatterning plastic layers such as photosensitive polyamide or photosensitive polyarylene ether ketone. The pillars
50
face upstream towards the ink supply cartridge
22
(
FIG. 2
) so that particles and air bubbles moving downstream toward the ink inlet
25
and into the channels
20
of the ink jet printhead are caught by the pillar members
50
.
Pillar members
50
,
50
′ preferably are formed around each hole
46
, so as to protect an upstream side
42
of the hole relative to fluid flow, as well as the downstream and other side
44
, so that air bubbles generated on the downstream side or other sides of the filtering, fluid flow hole, will also be held away from the fluid flow hole by a pillar. As shown in
FIGS. 5 and 6
, pillar height is controlled by the film thickness, the bevel angle, and the close spacing of the holes. On the upstream side
42
, the spacing of the holes
46
is such that a laser ablated, large diameter portion or trough portion
54
around one hole
46
overlaps the similar, large diameter portion or trough portion
54
of the neighboring holes
46
. Meanwhile, the small diameter holes themselves do not overlap with neighboring holes. The overlapping trough portions
54
around the laser ablated holes
46
result in the formation of the pillar members
50
, and fluid passageways
53
that exist below the top surface and side of the film e.g.,
42
.
In operation, the pillars or pillar members
50
project above a fluid flow surface areas defined by passageways
53
on the side
42
, so that they can trap and block dirt and air bubbles, thereby holding them away from direct contact with the fluid flow holes
46
. Fluid then can flow into the fluid flow holes by first flowing around and passing along passageways
53
between the pillars
50
. Air bubbles are held away from the fluid flow holes by the pillars due to the side tension of the air bubbles. In order for the air bubbles to pass through to the fluid flow holes, the air bubble must change shape to conform to the smaller space. This takes energy that would have to be provided by the flow of ink. Because the ink can flow around the air bubble, there is less energy available for distorting the air bubble. In this way, the air bubble tends to stay on the top side
42
of the pillars rather than move into the filter or filtering device cavities.
As can be seen, there has been provided an efficient fluid filtering device is provided for filtering unwanted contaminants from flowing fluid, such as ink flowing into an ink jet printhead. The efficient fluid filtering device includes a generally flat member having a first side and a second side, and a series of fluid flow holes formed through the flat member from the first side to the second side. Importantly, the efficient fluid filtering device also has a series of pillar members, including pillar members defining a trough portion around each fluid flow hole. The pillar members and the trough portions are arranged around each hole so as to efficiently prevent bubbles and contaminants in flowing fluid from impeding fluid flow from the first side through to the second side.
While the embodiments disclosed herein are preferred, it will be appreciated from this teaching that various alternative, modifications, variations or improvements therein may be made by those skilled in the art, which are intended to be encompassed by the following claims.
Claims
- 1. An efficient fluid filtering device comprising:(a) a generally flat member having a first side and a second side, said generally flat member comprising a thick laser ablated film material; (b) a series of fluid flow holes formed through said flat member from said first side to said second side; and (c) a series of pillar members including pillar members defining a trough portion around each fluid flow hole of said series of fluid flow holes, said pillar members and said trough portions being arranged so as to efficiently prevent bubbles and contaminants from impeding fluid flow from said first side through said second side.
- 2. The efficient fluid filtering device of claim 1, wherein said thick laser ablated film material comprises a polymer film.
- 3. The efficient fluid filtering device of claim 1, wherein said series of fluid flow holes comprise spaced apart linear arrays of said fluid flow holes.
- 4. The efficient fluid filtering device of claim 1, wherein said series of pillar members is comprised of pillar members formed interspersed between adjacent holes of said series of holes.
- 5. The efficient fluid filtering device of claim 3, wherein said linear arrays of said series of fluid flow holes comprise lateral arrays and diagonal arrays.
- 6. The efficient fluid filtering device of claim 5, wherein each pillar member of said series of pillar members includes a hole-facing surface having a beveled portion for facilitating and enhancing trapping of air bubbles away from adjacent fluid flow holes.
- 7. The efficient fluid filtering device of claim 6, wherein said series of pillar members is formed on said first side and on said second side of said generally flat member.
- 8. The efficient fluid filtering device of claim 6, wherein each pillar member of said series of pillar members has a plurality of said hole-facing surfaces.
- 9. The efficient fluid filtering device of claim 6, wherein hole-facing surfaces of said series of pillar members are formed angularly relative to a line through a lateral array of fluid flow holes of said series of fluid flow holes.
- 10. The efficient fluid filtering device of claim 6, wherein each fluid hole of said series of fluid holes is tapered.
- 11. The efficient fluid filtering device of claim 6, wherein each trough portion lies between pillars and above a fluid flow hole.
- 12. The efficient fluid filtering device of claim 6, wherein each trough portion has a generally circular top opening.
- 13. The efficient fluid filtering device of claim 6, wherein said series of pillar members is formed only on said first side of said generally flat member.
- 14. An ink jet printhead assembly comprising:(a) ink supplying manifold; (b) a printhead having ink ejecting nozzles and an ink inlet for receiving ink flowing from said ink supplying manifold; and (c) an efficient filtering device mounted across said ink inlet for blocking and preventing air bubbles and contaminants flowing with ink into said ink inlet towards said printhead, and for efficiently filtering such ink, said efficient filtering device including: (i) a generally flat member having a first side and a second side, said generally flat member comprising a thick laser ablated film material; (ii) a series of fluid flow holes formed through said flat member from said first side to said second side for filtering ink flowing into said ink inlet; and (iii) a series of pillar members including pillar members defining a trough portion around each fluid flow hole of said series of fluid flow holes, said pillar members and said trough portions being arranged so as to efficiently prevent bubbles and contaminants in flowing ink from impeding ink flow from said first side through said second side.
- 15. The ink jet printhead of claim 14, wherein said series of pillar members is formed on said first side and on said second side of said generally flat member.
- 16. The ink jet printhead of claim 14, wherein each fluid hole of said series of fluid holes is tapered.
- 17. The ink jet printhead of claim 14, wherein each trough portion lies between pillars and above a fluid flow hole.
- 18. The ink jet printhead of claim 14, wherein each trough portion has a generally circular top opening.
- 19. The ink jet printhead of claim 14, wherein said series of pillar members is formed only on said first side of said generally flat member.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4864329 |
Kneezel et al. |
Sep 1989 |
|
5154815 |
O'Neill |
Oct 1992 |
|
5204690 |
Lorenze, Jr. et al. |
Apr 1993 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2 225 229 |
May 1990 |
GB |