JPH07108689A - Thermal ink jet print head cartridge, flexible mutual connecting circuit used in said cartridge and production of thermal ink jet print head cartridge - Google Patents

Abstract

PURPOSE: To favorably perform the cleaning of orifice surfaces, prevent a clogging of the orifices from occurring, and improve a printing quality by providing an opening to feed an ink on the lower surface of a cartridge main body, and providing a plurality of resistance heating elements which vaporize the fed ink. CONSTITUTION: This print head cartridge 50 is equipped with a main body 12 and a resistance structure 24, but does not have an orifice plate by forming an orifice on a flexible mutual connection circuit 52. The flexible mutual connection circuit 52 is equipped with an orifice 54 for a first row, and an orifice 56 for a second row. The orifices are formed through the flexible mutual connection circuit 52 by laser-processing a conical opening through the flexible mutual connection circuit 52. The diameter of the orifices is formed in a manner to gradually become smaller as separating from the resistance structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to ink jet printers, and more particularly to ink jet printhead cartridges and methods of making the same.

[0002]

BACKGROUND OF THE INVENTION Ink jet printers generally use disposable ink jet printhead cartridges to replenish ink. Existing inkjet printhead cartridges, such as those shown in FIGS. 1 and 2, are described in “DisposableInk Jet H,” issued February 19, 1985 to Buck et al.
It is typically manufactured using a method similar to that described in commonly assigned U.S. Pat. No. 4,500,895, entitled "ead".

Prior art printhead cartridges include a cartridge body that stores ink.
The thin film resistance structure comprises a plurality of resistance heating elements attached to the cartridge body. The resistive structure typically comprises a central opening for supplying ink to the resistive heating element. Grooves are formed in the resistive structure using a barrier layer to distribute liquid ink from the openings to the resistive heating element. Ink is supplied to the openings in the resistive structure by overlapping openings in the openings in the cartridge body.

The resistive structure includes contact bonding pads provided around the periphery of the resistive structure. Bonding pads are bonding sites that connect the conductors of a flexible interconnect circuit to a resistive structure.
site-bonding place). The conductors supply current from the inkjet printer to the individual heating elements. The heating element consumes heat when an electric current is applied to it. The heat generated causes the ink to evaporate, thereby "jetting" it from the ink cartridge.

An orifice plate is attached to the resistance structure. The orifice plate includes a plurality of orifices that form inkjet nozzles when aligned with corresponding heating elements. Aligning the orifice plate with respect to the resistive element requires precise alignment and requires a separate manufacturing process. The orifice imparts shape and orientation to the ink drops ejected from the cartridge when the nozzle is activated.

The flexible interconnect circuit is attached to the cartridge body and the resistive structure. Flexible interconnect conductors are bonded to corresponding contact pads of the resistive structure by ablation or thermosonic welding, as known to those skilled in the art. An opening is formed in the flexible interconnect circuit to expose the end of the conductor for welding the flexible interconnect conductor to the resistive structure pad. The openings not only expose the ends of the conductor, but also the orifice plate so that the flexible interconnect does not cover the orifice.

After the conductor is welded to the contact pad, a resin is applied to the end of the conductor to protect the end of the conductor from corrosive ink. However, the resin crosses the orifice surface and bumps (b
Ump), which hinders effective cleaning and maintenance of the orifice face. The orifice surface is periodically cleaned with a printer wiper blade, or squeegee, to prevent ink buildup on the surface. The resin bumps prevent the wiper blade from making continuous contact across the entire orifice surface. As a result, ink buildup can occur at some of the orifices, ultimately clogging the orifices. If the orifice is clogged, not all of the ink droplets will adhere to the print medium, resulting in poor print quality.

Therefore, the cleaning of the orifice is promoted,
This improves the print quality of inkjet printers,
There remains a need for a method of manufacturing inkjet printheads with planar orifice surfaces that increases printhead life.

[0009]

SUMMARY OF THE INVENTION The above needs are met by an ink jet cartridge having a substantially planar surface to assist in cleaning printhead nozzles.

A thermal inkjet printhead cartridge for use in an inkjet printer having a carriage for receiving the inkjet printhead cartridge is described. The printhead cartridge includes an enclosed cartridge body that stores a liquid ink supply. The cartridge body has an opening for supplying ink to the lower surface. A thin film resistor structure is provided in contact with the liquid ink supply. The thin film resistance structure comprises a plurality of resistance heating elements that cause the ink supplied thereto to evaporate. The printhead cartridge is further connected to the resistive structure by a layer of conductive adhesive formed between the thin film resistive structure and the selecting means to conduct current between the selecting means and the resistive heating element. Means are provided for electrically selecting the resistance heating element. The layer of conductive adhesive is cured under controlled temperature and pressure,
A permanent conductive bond is formed between the resistive structure and the selection means.

Generally, the electrically conductive adhesive is composed of a polymer mixture having electrically conductive particles dispersed therein which conduct current in one direction between the selection means and the resistive heating element. Preferably, the polymer mixture contains an epoxy compound and dispersed conductive particles of any one of gold and silver.

[0012] Preferably, the selection means comprises a flexible interconnect circuit. Typically, a flexible interconnect circuit is formed on the top and bottom surfaces, a plurality of conductors mounted on the bottom surface of the substrate, and an orifice above the resistive heating element when the flexible interconnect circuit is connected to the printhead cartridge. As such, it comprises an interconnect substrate having a plurality of spaced orifices. Preferably, the orifice is a conical opening formed in the flexible interconnect substrate, the lower surface of the substrate having a larger opening than the upper surface of the substrate. The orifices are arranged as first and second row orifices, with the first row offset from the second row and adjacent orifices in each row offset from each other. The orifices may also be offset within each row.

An advantage of the present invention is that it requires fewer steps to manufacture an inkjet printhead cartridge.

Another advantage of the present invention is that the manufacturing process is less complex.

Yet another advantage of the present invention is the lack of a separate orifice plate in the inkjet printhead cartridge.

Yet another advantage of the present invention is that the conductors of the flexible interconnect are short and thus have low inductance.

The foregoing and other objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of the preferred embodiments, which proceeds with reference to the accompanying drawings.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a prior art inkjet printer cartridge 10 is illustrated. The detailed description of the invention provided below logically follows the description of the prior art, as many of the components remain the same. Therefore, common components between the prior art cartridge and the cartridge of the present invention are given common reference numerals. The printer cartridge 10 includes a cartridge body 12 that acts as an ink storage chamber. The body 12 is made of plastic by injection molding. Attached to the outer wall of the body is a flexible interconnect circuit 14. Flexible interconnection
It extends along the outer wall and wraps around the lower surface 16 of the body 12. The interconnect 14 is therefore made of a flexible polymeric material for wrapping around the lower surface 16. Flexible interconnects are usually made from polyamide and
Manufactured by the corporation under the Kapton trade name.

Flexible interconnect 14 is a corresponding thermal resistance heating element (not visible) from the printer (not shown).
There is a plurality of conductors generally indicated at 18 for supplying current to the. The conductors 18 are attached to the underside of the flexible interconnect 14 on the body 12 by traditional printer circuit board techniques.
Is formed adjacent to. In the preferred embodiment, conductor 18
Are made of gold-plated copper. The conductor is wide enough to carry the amount of current required to operate the heating element. Each of the conductors 18 generally contacts two corresponding printer contacts on the inkjet printer.
A corresponding contact pad indicated by 0 is provided. Since the conductor is formed on the underside of the flexible interconnect 14,
Circular vias are flexible interconnects 1
4 is formed to face the contact pad of the printer.
Thus, the bias exposes the printer contact pads to allow electrical contact between the contact pads and the flexible interconnect printer contact pads 20.

Referring now to FIG. 2, a cutaway view of printer cartridge 10 is shown. For purposes of illustration, the flexible interconnect 14 is shown stretched flat. However, as mentioned above, the flexible interconnect is bent 90 ° and wrapped around the underside of the cartridge body.

The cartridge body 12 includes a recess 22 (not visible) formed in the lower surface 16 to receive a thin film resistive structure 24 with resistive heating elements. The recess 22 has an opening 26 therein for supplying ink to the resistance structure 24. The resistor 24 has a corresponding opening 28 formed therein which overlaps a cartridge opening 26 that supplies ink to the thin film resistive element.

The thin film resistor structure 24 is a traditional thin film integrated circuit formed on a glass or silicon substrate.
A plurality of thin film resistive heating elements are formed on a substrate using traditional thin film integrated circuit manufacturing techniques. The resistive elements (not visible) are coupled to corresponding conductors formed on the substrate by sputtering to individually select the at least one resistive element. There are various precision interconnection methods between conductors and resistive elements, for example, each conductor can be coupled to one corresponding resistive element, or, alternatively,
The conductor can be coupled to one or more resistive elements and the multiplexing mechanism used. The invention described below applies regardless of the precise interconnection method between the resistive structure conductor and the resistive element.

Each of the resistive structure conductors (not visible) comprises a corresponding contact pad, generally indicated at 30, provided around the resistive structure. Contact pad 30 is typically a metal square or rectangular pad that forms the bond site. Methods of forming such contact pads on integrated circuits are well known to those skilled in the art. Contact pad 30
Provides sufficient area to form a bond between the flexible interconnect circuit conductor 18 and the corresponding resistive structure conductor, as described further below.

The resistance structure 24 is located in the recess 22 and
It is fixed to the lower surface of the main body 12 with an adhesive. In this configuration, the ink stored in the body 12 is supplied to the surface of the resistive structure 24 through the openings 26 and 28. Ink passages are formed on the surface of the resistive structure using a barrier layer to supply ink to the individual resistive heating elements. The method of forming the passage is described in, for example, Chan et al.
US Pat. No. 4,694,308, “Barrier,” issued Sep. 15, 1987 and commonly assigned to the present application.
Layer and Orifice Plate f
or Thermal Ink Jet Print
The title is "Ead Assembly". The ink supplied to the individual heating elements is then vaporized by supplying an electric current to the required heating elements.

The orifice plate 32 is attached to the resistive structure using an adhesive layer. In the preferred embodiment, the orifice plate is formed from gold-plated copper. The orifice plate comprises a first row of orifices 34 and a second row of orifices 36.
The orifice is located directly above the corresponding resistance heating element. The orifice imparts shape and orientation to the vaporized ink to form an ink drop. The layered combination of resistive heating elements, the corresponding ink supply passages, and the corresponding orifices form an inkjet nozzle.

The flexible interconnect circuit 14, as shown in FIG. 2, has an opening 38 formed therein that is slightly larger than the resistive structure 24. Opening 38 is formed in the interconnect to expose a contact 40 formed at the distal end of the flexible interconnect conductor. Commonly assigned US Pat. No. 4,635,073 to Hanson, Jan. 6, 1987, entitled "R
eplaceableThermal Ink Jet
Component and Thermosoni
c Beam Bonding Process fo
The contacts 40 are, in the prior art, resistive contacts 40 corresponding to the corresponding contact pads 30 on the resistive structure 24, as described in what is entitled "r Fabricating Same".
Exposed so that ultrasonic ablation welding can be performed. Opening 38 also exposes orifice plate 32. Once the openings 38 are formed, the contacts 40 are positioned over the corresponding contact pads 30 on the resistive structure 24,
The contact pads are welded together using the ablation welding method described above.

The remainder of the flexible circuit is secured to the cartridge body using adhesive strips (not shown). The contact 40 is then covered with resin (not shown),
Avoid contact pad exposure to corrosive inks. However, the resin creates bumps above the contacts 40 that destroy the planarity of the orifice surface. The bumps prevent the orifice plate from being wiped at the printer service station. Therefore, the nozzle is more likely to be clogged, as described in the Technical Background section.

Referring to FIG. 3, a cutaway view of a printhead cartridge 50 according to the present invention is shown. The printhead cartridge 50 also includes the body 12 and the resistive structure 24, but by forming the orifices on the flexible interconnect circuit 52, the orifice plate is eliminated. Flexible interconnection circuit 5
2 comprises a first row of orifices 54 and a second row of orifices 56. The orifice is formed through the flexible interconnect 52 by laser machining a conical opening through the flexible interconnect 52. In the preferred embodiment, the diameter of the orifice is made smaller as it moves away from the resistive structure, as shown in FIG. The orifices in the first and second rows are
The orifices are formed on the flexible interconnect 52 such that the orifices align with the corresponding heating elements of the resistive structure 24 when the flexible interconnect 52 is attached to the resistive structure 24. Therefore, the flexible interconnection circuit 52
Eliminates the additional orifice plate required by the prior art.

The orifice is a flexible interconnect,
Formed in the area that will be used as an opening for passage to the flexible interconnect contacts 40. The flexible interconnect contacts 40 are connected to the resistive structure 24 as taught in the prior art.
Instead of ablation welding to the corresponding contact of
Flexible interconnect contacts 40 are connected to corresponding resistive structure contacts 30 using a conductive adhesive layer formed between flexible interconnect contacts 40 and corresponding resistive connect contacts 30.

The conductive adhesive must carry current in only one direction, ie, between the flexible interconnect contact 40 and the corresponding resistive structure contact 30. Otherwise, a short circuit will occur between adjacent resistive contacts. Unidirectional conductive adhesives are commercially available and are known as "Z-axis" conductive adhesives. A "Z-axis" conductive adhesive is composed of polymerized epoxy with conductive particles suspended therein. In the preferred embodiment, the conductive adhesive contains suspended particles of gold. Particles of silver or copper are suitable equivalent materials. An example of the "Z-axis" conductive adhesive is AI Tech, Princeton, NJ
Nologies, Inc. LZSP8 supplied by
415-FP. LZSP8415 is a "B-stageable" Z-axis conductive poxy paste, which is an anisotropic conductive adhesive.

Flexible interconnect 52 is connected to resistive structure 24 using conductive adhesive in the following manner. A strip of conductive adhesive is applied to the resistive structure contacts 30 or, alternatively, the flexible interconnect contacts 40.
The conductive adhesive strip is then compressed between the resistive structure and the flexible interconnect using compressive force. In the preferred embodiment, the cartridge body is supported by a fixture, the resistive structure 24 is attached to the cartridge body, and the flexible interconnect is pressed toward the underside of the cartridge body. The compressive force is applied for a predetermined time according to the environmental conditions defined by the specifications of the conductive adhesive. In the preferred embodiment, the conductive adhesive has a high boiling point to prevent liquefaction of the resistive element due to heat consumption during use. During the curing process, a maximum of about 100-20
0p. s. i (pound persquare in
ch), the ambient temperature of 200 to 250 ° C., preferably 220 ° C. and 100 p. s. i. Use the pressure of. The rest of the flexible interconnect 52,
It is then attached to the cartridge body 12 using a conductive adhesive strip. Alternatively, the remainder of the flexible interconnect 52 can be attached first to the pen body 12 and then the resistive contact pads to the corresponding resistive structure contacts 30.

In another embodiment of the present invention, the conductive adhesive is replaced with a selectively applied, low melting point conductive solder between the resistive structure contacts 30 and the flexible interconnect contacts 40. The solder, which typically comprises tin and lead, is selectively applied to the resistive structure contacts 30 or the flexible interconnect contacts 40. The structural contacts 30 are aligned with the corresponding flexible interconnect contacts and heat is applied. The heat causes the solder to flow, forming a conductive bond between the resistive structure contact 30 and the flexible interconnect contact 40. The boiling point of the solder is necessarily lower than the melting point of the flexible interconnect circuit so that the flexible interconnect will not melt when heat is applied.

A cutaway view of a second embodiment of the flexible interconnect 58 is shown in FIG. Flexible interconnect 58
It comprises a contact pad 60 rotated by 90 ° from the contact 40 shown in FIG. The flexible interconnect contact configuration shown in FIG. 4 makes the conductor 62 substantially straight and reduces the inductance of the conductor caused by the sharp corners of the conductor. Also,
The conductors 62 are shorter than the corresponding conductors 18 in FIG. 3 to further lower the inductor and further reduce electromagnetic emissions and propagation delays due to the conductors. Moreover, the conductor 62 does not require sharp corners, which can further reduce the inductance of the conductor.

Referring now to FIG. 5, there is shown a plan view of the assembled cartridge of FIG. The plan view shown in FIG. 5 shows a part of the lower side 16 of the cartridge main body which is cut out so as to expose the resistance structure 24 which is partially cut out. The resistive structure 24 is connected to the flexible interconnect 58 by conductive adhesive layers 72 and 73 formed on the contact pads 60. The openings 28 supply ink to the orifices 54 and 56 of the first and second rows, respectively, by the groove means formed in the resistive structure (not visible). The conductive adhesive layer connects the resistive structure contacts 30 (not visible) to the corresponding contact pads 6
Connect to 0.

Each of the first and second row orifices 154 and 156 are illustrated in more detail. As shown in FIG. 5, the orifices in each row form two rows of orifices that are horizontally offset and parallel to each other. The orifices are biased closer in the row to bring them closer together, increasing the resolution of the printhead. Rows 154 and 1
56 are arranged such that the orifices in one row are placed more perpendicularly to each other and the orifices in one row are placed between the orifices in the other row. Vertically offsetting the rows increases the effective resolution of the printhead.

A cross-sectional view taken along the line BB of FIG. 5 is shown in FIG. Line BB is a flexible interconnect contact pad 66.
And along the corresponding orifice 68. The cross-sectional view shows that the flexible interconnect 58 has a conical orifice 68 formed therein. The orifices, in the preferred embodiment, are formed by a precision milling process, as described above, which creates an opening that becomes progressively smaller away from the resistive structure. The orifice 68 is formed directly opposite a thin film resistor 78 formed on a resistively structured silicon substrate 76 using traditional integrated circuit fabrication techniques. A barrier layer 70 is formed on the substrate which, in addition to protecting the underlying integrated circuit from corrosive ink, also defines channels for distributing liquid ink across the surface of the resistive structure. The orifice 68, thin film resistor 78, and surrounding barrier layer form an ink jet nozzle.

Connected to flexible interconnect 58 is a conductor 64 formed from gold-plated copper. Flexible interconnect contact pad 66 is formed at its distal end. Contact pads 66 are formed directly opposite corresponding thin film resistive contact pads 74 formed on substrate 76 using traditional sputtering techniques, as is known in the integrated circuit manufacturing art. Formed between the resistive contact pad 66 and the corresponding thin film resistive contact pad 74 is a conductive adhesive layer 72. The conductive adhesive contains dispersed particles of a conductive substance. The particles are well dispersed so as not to cause a short circuit between adjacent conductors, but the resistive contact pad 66 and corresponding thin film contact pad 74
Dense enough to ensure proper contact with.

As is apparent from FIG. 6, the orifice surface is substantially flat. The barrier layer is sufficiently high in the preferred embodiment such that the flexible interconnect 58 is substantially planar. Alternatively, the height of barrier layer 70 can be approximately equal to the combined height of thin film contact pad 74 and adhesive layer 72. This causes a slight tilt in the flexible interconnect 58, but the tilt is much less than that caused by the resins used in the prior art. Thus, the substantially planar orifice surface provides effective cleaning of the nozzles, as described herein, to increase print quality and inkjet cartridge life.

In use, the printhead described above is inserted into a printer cartridge (not shown) having a printer contact pad corresponding to the contact pad 20. The printer contact pad is connected to printer drive electronics that provide activation signals to the printer contact pad. The circular via formed in the flexible interconnect exposes the contact pad 20 to the corresponding printer contact pad.
The printer contact pad and the corresponding contact pad 20 make physical contact by inserting the print head into the carriage. The electrical connection between the printer drive electronics and the resistive heating element is thus made.

The actuation signal generated by the printer drive electronics is then provided to the resistive heating element using the flexible interconnect. The actuation signal thus supplied causes the resistive element to consume thermal energy which vaporizes the liquid ink placed in contact with the predetermined resistive heating element. The evaporated ink is shaped and guided by the corresponding orifice to form an ink drop.

While the principles of the invention have been illustrated and illustrated by its preferred embodiments, it will be apparent that the invention can be modified in structure and detail without departing from such principles. We claim all modifications and variations that fall within the scope of the claims.

As described above, the present invention relates to [1] a thermal inkjet printhead cartridge (10) used in an inkjet printer having a carriage for receiving an inkjet printhead cartridge;
An enclosed cartridge body (12) for storing a liquid ink supply, the body (12) having an opening (26) on its lower surface for supplying ink; in contact with the liquid ink supply A thin film resistive structure (24) having a plurality of resistive heating elements provided; means (58) for electrically selecting one or more resistive heating elements, said means (5)
8) The resistive heating element selected by 8) consumes thermal energy to evaporate liquid ink placed in contact with the element; and formed between the thin film resistive structure and the selecting means. It is characterized in that it comprises a layer of electrically conductive adhesive (72) which conducts an electric current between it and the resistance heating element, and has the following preferred embodiments.

[2] In the above [1], the conductive adhesive (72) is composed of a polymer mixture having conductive particles dispersed therein, and conducts an electric current between the selection means and the resistance heating element. It is characterized by

[3] The above-mentioned [2] is characterized in that the particles are dispersed in the polymer mixture (72) to conduct an electric current in one direction.

[4] The above-mentioned [2] is characterized in that the polymer mixture (72) contains an epoxy compound and dispersed conductive particles made of either gold or silver.

[5] In the above [1], the thin film resistance structure is a substrate (24) in which a fluid passage for supplying ink from an ink supply source to a resistance heating element is formed. ) Is attached to the cartridge body (12) such that the fluid passage is in contact with the ink supply; and a plurality of conductors coupled to the resistive heating element for conducting current to the resistive heating element, the conductors being electrically conductive. Connected to the selection means by a sex adhesive.

[6] In the above [5], the selection means is
Flexible interconnect circuit having a top surface and a bottom surface (5
8); and a plurality of conductors (62) attached to the underside of the flexible interconnect circuit, each electrically connected to a corresponding resistive structure conductor by a conductive adhesive. .

[7] In the above [5], the selecting means is
It is characterized in that it further comprises a plurality of orifices (154, 156) for guiding the vaporized ink by corresponding resistance heating elements.

The present invention also relates to [8] a thermal ink jet print head cartridge for an ink jet printer having a carriage for receiving an ink jet print head cartridge; a liquid ink having an opening for supplying ink on a lower surface. Enclosed cartridge body (12) for storing a supply; thin film resistive structure (24) having a plurality of resistive heating elements provided in contact with a liquid ink supply; top, bottom and flexible interconnect circuitry A flexible interconnect circuit (58) comprising a plurality of conductors mounted on the lower surface and a plurality of orifices for directing vaporized ink by corresponding resistance heating elements; and electrically connecting the flexible interconnect conductors to the resistive structure. (58) the current to the flexible interconnection circuit means Means for directing between the anti-heating element; characterized in that it comprises a, with a preferred embodiment as follows.

[0050]

[9] In the above [8], the flexible interconnection circuit is provided with a bias formed therein to electrically contact between the flexible interconnection conductor and the corresponding conductor of the printer.

[10] In the above [8], the cartridge main body is provided with a recess (26) formed in the lower surface, and when the resistance structure is received in the recess, the resistance structure is flush with the lower surface of the cartridge main body. It is characterized by receiving.

[11] In the above [8], the flexible interconnection circuit (58) is formed of a flexible polymer.

[12] In the above [8], the connecting means is provided with an ablation welded portion formed between the flexible interconnect conductor and the corresponding thin film resistance structure conductor.

[13] In the above [8], the connecting means comprises a layer of conductive adhesive (72) formed between the thin film resistance structure and the flexible interconnect conductor, and the electric current is selected by means of the resistance heating. It is characterized by leading between the elements.

[14] In the above [8], the connecting means comprises a layer of selectively applied low melting point conductive solder formed between the thin film resistance structure and the flexible interconnect conductor. , Directing an electric current between the selection means and the resistance heating element.

The invention further provides [15] a flexible interconnect circuit for supplying current to a predetermined one of a plurality of thin film heating elements of a thermal ink jet printhead cartridge; the flexible interconnect having an upper surface and a lower surface. A substrate (58); a plurality of conductors (62) attached to the lower surface of the substrate; and a plurality of orifices (154, 156) formed in the substrate, the orifices (154, 154).
156) is spaced apart such that the orifice is above the resistive heating element when the flexible interconnect circuit is connected to the printhead cartridge; Has an embodiment.

[16] In the above [15], further, for each conductor, a flexible interconnection contact pad (2
0), a printer contact pad (60), and a bias, the flexible interconnect contact pad and the printer contact pad being formed on a lower surface of the substrate, the bias being formed opposite the printer contact pad and through the substrate,
The printer contact pad is exposed on the upper surface of the substrate.

[17] In [15] above, the orifices (154, 156) are formed in the flexible interconnect substrate, and the lower surface of the substrate is a conical opening having an opening larger than the upper surface of the substrate. It is characterized by

[18] In the above [15], the orifices are arranged as the orifices (154) in the first row and the orifices (156) in the second row, and the first row is offset from the second row, and It is characterized in that adjacent orifices are offset from each other.

[19] In the above [15], the conductor (6
2) are installed generally linearly along the flexible interconnect, wherein at least one of the conductors is installed between the first row orifices and the second row orifices. .

The invention also provides [20] a method of manufacturing a thermal ink jet printhead cartridge; the step of providing an enclosed cartridge body for liquid ink storage having an opening for supplying ink to a lower surface thereof. Preparing a thin film resistance structure having a plurality of resistance heating elements in contact with a liquid ink supply source; a thin film resistance structure for supplying liquid ink to the resistance heating elements through openings in the cartridge body. Attaching to the underside of the cartridge body; preparing a flexible interconnect circuit having a plurality of conductors;
Forming a layer of electrically conductive adhesive between the thin film resistive structure and the flexible interconnect conductor to electrically connect the flexible interconnect conductor to the resistive heating element; and conducting under predetermined temperature and pressure conditions. Curing an adhesive adhesive; and having the following preferred embodiment.

[21] The method of [20] above further comprises the step of forming a plurality of orifices in the flexible interconnect such that each orifice is formed above a corresponding resistance heating element. .

[22] In the above [20], the step of forming a plurality of orifices includes the step of laser processing the flexible interconnect to form a conical orifice.

[23] In [20] above, the step of curing the conductive adhesive is performed at a temperature of about 250 ° C. at maximum.

[24] In [20] above, the step of curing the conductive adhesive is performed at a pressure of up to about 200 pounds per square inch.

[0066]

According to the present invention, since the orifice surface can be made substantially flat, the cleaning of the orifice surface can be favorably performed by the pudding wiper blade that traverses the orifice surface, and thus the ink The buildup on the orifice surface, and eventually the clogging of the orifice does not occur, so that the print quality is improved and the life of the inkjet cartridge is extended.

Further, according to the present invention, the number of steps required for manufacturing the ink jet print head cartridge is small, and the complexity of the manufacturing process can be reduced.

Further, the present invention eliminates the need to provide a separate orifice plate in the ink jet printhead cartridge, and also allows the flexible interconnect conductors to be short and thus their inductance low.

[Brief description of drawings]

FIG. 1 is a perspective view of a prior art inkjet printhead cartridge.

FIG. 2 is a cutaway view of the prior art inkjet printhead cartridge of FIG.

FIG. 3 is a cutaway view of a first embodiment of an inkjet printhead cartridge according to the present invention.

FIG. 4 is a cutaway view of a second embodiment of an inkjet printhead cartridge according to the present invention.

5 is a plan view of the second embodiment of the inkjet printhead shown in FIG. 4, showing the cut-out portion of the cartridge body and the resistance structure.

6 is a cross-sectional view taken along line BB of FIG.

[Explanation of symbols]

 10, 50 Printhead cartridge 12 Cartridge body 14, 52, 58 Flexible interconnection circuit 16 Cartridge body lower surface 20, 30, 60, 66, 74 Contact pad 22 Recess 24 Thin film resistance structure 26, 28 Open 40 Contact 54, 56, 68 , 154, 156 Orifice 62, 64 Conductor 70 Barrier layer 72, 73 Conductive adhesive layer 76 Silicon substrate 78 Thin film resistor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41J 29/00 D

Claims (4)

[Claims] 1. A thermal inkjet printhead cartridge (10) for use in an inkjet printer having a carriage for receiving an inkjet printhead cartridge; an enclosed cartridge body (12) for storing a liquid ink supply. , The body (1
2) has an opening (26) on the lower surface for supplying ink; a thin film resistive structure (24) having a plurality of resistive heating elements provided in contact with a liquid ink supply; one or more Means for electrically selecting resistive heating elements (58)
A resistive heating element selected by the means (58) consumes thermal energy to vaporize liquid ink placed in contact with the element; and between the thin film resistive structure and the selecting means. A printhead cartridge (1) comprising a layer of electrically conductive adhesive (72) formed on the substrate and conducting an electric current between the selection means and the resistive heating element.
0). 2. A thermal inkjet printhead cartridge for an inkjet printer, comprising a carriage for receiving an inkjet printhead cartridge; an enclosure for storing a liquid ink supply having an opening on the bottom surface for supplying ink. Cartridge body (12); thin film resistive structure (2) having a plurality of resistive heating elements provided in contact with a liquid ink supply
4); a flexible interconnect circuit (58) comprising a plurality of conductors attached to the top surface, the bottom surface, and the bottom surface of the flexible interconnect circuit, and a plurality of orifices for directing the ink vaporized by the corresponding resistive heating elements; And a means for electrically connecting (58) the flexible interconnect conductor to the resistive structure to conduct current between the flexible interconnect circuit means and the resistive heating element. 3. A flexible interconnect circuit for supplying current to a predetermined one of a plurality of thin film heating elements of a thermal inkjet printhead cartridge; a flexible interconnect substrate (58) having an upper surface and a lower surface; A plurality of conductors (62) attached to the lower surface; and a plurality of orifices (154, 156) formed in the substrate, the orifices (154, 156) when the flexible interconnect circuit is connected to the printhead cartridge. A flexible interconnect circuit, the orifices being spaced apart such that they are above the resistive heating element. 4. A method of manufacturing a thermal inkjet printhead cartridge; providing an enclosed cartridge body for liquid ink storage having an ink supply opening on the lower surface; a liquid ink supply source therein. Providing a thin film resistive structure comprising a plurality of resistive heating elements in contact with the thin film resistive structure on a lower surface of the cartridge body such that liquid ink is supplied to the resistive heating element through an opening in the cartridge body. Mounting; preparing a flexible interconnect circuit having a plurality of conductors; forming a layer of conductive adhesive between the thin film resistor structure and the flexible interconnect conductor to electrically connect the flexible interconnect conductor to a resistive heating element. Curing the conductive adhesive under the prescribed temperature and pressure conditions. A method of manufacturing a thermal inkjet printhead cartridge.