JP6614868B2 - Liquid discharge head and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid discharge head that discharges a plurality of types of liquid, and a method of manufacturing such a liquid discharge head.

  As a liquid discharge head mounted on a liquid discharge apparatus such as an ink jet recording apparatus, one capable of discharging a plurality of types of liquid is known. Patent Documents 1 and 2 describe liquid discharge heads that discharge black, cyan, magenta, and yellow inks. The liquid discharge head has a plurality of liquid paths each having a discharge port. Liquid paths through which different types of liquid are supplied are provided separately from each other, and therefore only a predetermined type of liquid is discharged from each discharge port.

Japanese Patent No. 4532705 JP 2010-12625 A

  In the manufacturing process of the liquid discharge head, there is a possibility that liquids are mixed without properly separating the liquid paths through which different types of liquids are supplied due to manufacturing defects or the like. When the liquid is ink, color mixing occurs. For this reason, conventionally, evaluation may be performed by actually ejecting liquid in the final step of the manufacturing process and drawing an evaluation pattern. By evaluating the evaluation pattern, liquid mixing or color mixing can be detected. However, even if the inspection is performed using the evaluation pattern, it is not always possible to detect the liquid mixture or color mixture, and there is a possibility of overlooking the liquid mixture or color mixture.

  As another inspection method, a method of measuring the pressure change in the liquid path by individually depressurizing or pressurizing the liquid path after sealing the liquid path can be considered. However, a large number of discharge ports are generally formed in the liquid discharge head, and it may be difficult to close all the discharge ports in order to seal the liquid path. Therefore, these inspection methods have room for improvement in terms of reliability.

  An object of the present invention is to provide a liquid discharge head capable of detecting the mixing of different liquids with higher reliability and a method for manufacturing the same.

The liquid discharge head of the present invention has a substrate and a plurality of element substrates provided on the substrate. Each element substrate communicates with a first discharge port that discharges a first liquid , a first liquid path through which the first liquid flows, and a second liquid that discharges a second liquid different from the first liquid . through the discharge port and the communication, the first second liquid flows, to impart a second liquid path adjacent via the adhesive layer and the first liquid path, an energy for discharging the first liquid A heating resistance element, a second heating resistance element that imparts energy for ejection to the second liquid, a first conductive layer that forms at least a part of the wall surface of the first liquid path, and a second A second conductive layer that is at least part of the wall surface of the liquid path and is electrically independent from the first conductive layer, a first pad that is electrically connected to the first conductive layer, And a second pad electrically connected to the two conductive layers . The substrate has a first common channel that communicates with the first liquid path of all element substrates, and a second common channel that communicates with the second liquid path of all element substrates, The first conductive layer of one element substrate is electrically connected to the first pad, and the second conductive layer of any one element substrate is electrically connected to the second pad.

The method of manufacturing a liquid discharge head according to the present invention includes a step of filling the first liquid path into the first liquid path communicating with the first discharge port for discharging the first liquid, and the second liquid discharging the second liquid. A step of filling the second liquid passage into the second liquid passage adjacent to the first liquid passage through the adhesive layer, and at least part of the wall surface of the first liquid passage. A first pad electrically connected to the first conductive layer , and a second conductive layer constituting at least a part of the wall surface of the second liquid path, wherein the second conductive layer is electrically connected from the first conductive layer. Measuring electrical characteristics between the second pad and the second pad electrically connected to the independent second conductive layer .

  ADVANTAGE OF THE INVENTION According to this invention, the liquid discharge head which can detect mixing of a different liquid with higher reliability, and its manufacturing method can be provided.

FIG. 3 is an exploded perspective view of the liquid discharge head according to the first embodiment of the present invention. FIG. 2 is a partially broken perspective view showing a configuration of an element substrate of the liquid ejection head of FIG. 1. FIG. 2 is a schematic partial cross-sectional view of the liquid ejection head in FIG. 1. FIG. 4 is a schematic partial cross-sectional view of a liquid discharge head showing a portion A in FIG. 3. FIG. 4 is a schematic plan view of a support substrate as seen from the line BB in FIG. 3. FIG. 6 is a schematic diagram of a liquid ejection head according to a second embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The present embodiment relates to a liquid discharge head that includes an electrothermal conversion element and discharges a plurality of types of ink. However, the present invention is not limited to this, and can be applied to, for example, a liquid discharge head using a piezoelectric element and a liquid discharge head that discharges liquid other than ink.

  FIG. 1 is an exploded perspective view of the liquid discharge head of this embodiment. The liquid ejection head 1 includes an element substrate 11, an electric wiring member 12, and a support member 13 that supports the element substrate 11 and the electric wiring member 12. The electrical wiring member 12 includes a plurality of external connection pads 14 that are electrically connected to the outside of the liquid ejection head 1. The support member 13 holds ink tanks of a plurality of colors (not shown). The liquid discharge head 1 of the present embodiment holds ink tanks of three colors of cyan, magenta, and yellow, but the number of ink tanks and the ink color are not limited to this.

  FIG. 2 is a perspective view of the element substrate 11, and FIG. 3 is a schematic cross-sectional view of the liquid discharge head 1. The element substrate 11 includes a support substrate 15 made of silicon (Si) and a discharge port forming member 16 provided on the support substrate 15. The discharge port forming member 16 is made of a resin material and is formed by a photolithography technique. The support substrate 15 has three liquid supply paths extending in the longitudinal direction in parallel with each other. Each liquid supply path corresponds to ink of three colors, cyan, magenta, and yellow. In the following description, these three colors of ink may be referred to as a first liquid, a second liquid, and a third liquid. In addition, the liquid supply paths through which the first liquid, the second liquid, and the third liquid circulate may be referred to as a first liquid supply path 17a, a second liquid supply path 17b, and a third liquid supply path 17c, respectively. is there.

  The discharge port forming member 16 is formed with a plurality of discharge ports from which ink is discharged. In the following description, the discharge port for discharging the first liquid is the first discharge port 18a, the discharge port for discharging the second liquid is the second discharge port 18b, and the discharge port for discharging the third liquid is the first discharge port. 3 discharge ports 18c. The first to third discharge ports 18a to 18c communicate with the first to third liquid supply paths 17a to 17c, respectively. One row of discharge ports arranged in a straight line parallel to each liquid supply path 17 forms one discharge port row 19. In the present embodiment, a pair of discharge port arrays 19 communicating with the liquid supply paths 17a to 17c are provided on both sides of the liquid supply paths 17a to 17c.

  The support substrate 15 is provided with a heating resistance element (electromagnetic heat conversion element) so as to face each discharge port. In the following description, the heating resistance elements corresponding to the first to third liquids may be referred to as first to third heating resistance elements 20a to 20c, respectively. The first to third heating resistance elements 20a to 20c respectively apply energy for ejection to the first to third liquids. Electrode pads 21 are provided on both sides of the support substrate 15 in the longitudinal direction x. The electrode pad 21 is electrically connected to the external connection pad 14 by an electric wiring (not shown) passing through the electric wiring member 12. A part of the electrode pad 21 is connected to the heating resistor element in order to define the driving voltage of the heating resistor element. The other part of the electrode pad 21 (first to third pads 21a to 21c (see FIG. 5)) is connected to first to third anti-cavitation layers 34a to 34c described later.

  The discharge port forming member 16 is provided with a pressure chamber corresponding to each discharge port. The discharge port forming member 16 defines a pressure chamber together with the support substrate 15. In the following description, the pressure chamber through which the first liquid circulates is the first pressure chamber 22a, the pressure chamber through which the second liquid circulates is the second pressure chamber 22b, and the pressure chamber through which the third liquid circulates is the first. 3 pressure chambers 22c. First to third discharge ports 18a to 18c communicating with the first to third pressure chambers 22a to 22c are opened on the surface of the discharge port forming member 16 facing the recording medium.

  Liquid channels connected to the ink tank are formed in the support member 13, and each liquid channel is connected to the liquid supply path 17 of the support substrate 15. The support substrate 15 is fixed to the support member 13 with an adhesive layer 27. In the following description, the first liquid channel 23a flows through the liquid channel through which the first liquid flows, the second liquid channel 23b flows through the liquid channel through which the second liquid flows, and the third liquid flows. The liquid channel may be referred to as a third liquid channel 23c. The first pressure chamber 22a, the first liquid supply path 17a, and the first liquid flow path 23a are referred to as a first liquid path 24a. Similarly, the second pressure chamber 22b, the second liquid supply path 17b, and the second liquid flow path 23b are referred to as a second liquid path 24b. Similarly, the third pressure chamber 22c, the third liquid supply path 17c, and the third liquid flow path 23c are referred to as a third liquid path 24c. The first liquid path 24a communicates with the first discharge port 18a, the second liquid path 24b communicates with the second discharge port 18b, and the third liquid path 24c communicates with the third discharge port 18c. ing. The first to third liquid paths 24a to 24c are separated from each other, and ink mixing between the first to third liquid paths 24a to 24c is prevented. Each ink (first to third liquids) in the ink tank is supplied to the pressure chambers 22a to 22c through the liquid flow paths 23a to 23c and the liquid supply paths 17a to 17c. Each ink is ejected from the ejection port by bubbles generated by the heat generating action of the heating resistance elements 20a to 20c in the pressure chambers 22a to 22c. As a result, a predetermined pattern is printed on the recording medium. The ink is exposed to a high temperature but has the property of not being denatured by the high temperature.

FIG. 4 is a schematic partial cross-sectional view of the liquid discharge head showing a portion A of FIG. This figure shows only the periphery of the pressure chamber 22a provided with the heating resistor element 20a, but the same applies to the other pressure chambers. The heating resistance element 20 a is provided on the support substrate 15 with an interlayer film 31 interposed therebetween. On the support substrate 15, a wiring 32 that connects the heating resistor element 20 a to the electrode pad 21 is provided. The entire surface of the heating resistance element 20a and the wiring 32 is covered with a protective film 33 made of SiO _2. The heating resistance element 20a is covered with a conductive anti-cavitation layer 34a via a protective film 33. The anti-cavitation layer 34a is made of Ta. The anti-cavitation layer 34a protects the heating resistance element from the water hammer effect that occurs when the bubbles of the ink generated by heating disappear. The anti-cavitation layer 34a constitutes a part of the wall surface 25 of the pressure chamber 22a and directly contacts the ink. In the following description, the cavitation resistant layers covering the second to third heating resistance elements 20b to 20c may be referred to as second to third cavitation resistant layers 34b to 34c, respectively.

  FIG. 5 is a plan view of the element substrate showing the liquid flow path and the anti-cavitation layer. The anti-cavitation layers 34a to 34c form a closed strip-like path extending along the heating resistance elements 20a to 20c on both sides of the liquid supply paths 17a to 17c, and cover the heating resistance elements 20a to 20c. The anti-cavitation layers 34a to 34c are provided for each heating resistance element corresponding to each color ink. The first to third cavitation resistant layers 34a to 34c are independent from each other, and are provided electrically independently from each other. A discharge port forming member 16 is formed above the anti-cavitation layers 34a to 34c.

  The first anti-cavitation layer 34a is electrically connected to the first pad 21a by the conductive first connection layer 26a. The second anti-cavitation layer 34b is electrically connected to the second pad 21b by the conductive second connection layer 26b. The third anti-cavitation layer 34c is electrically connected to the third pad 21c by the conductive third connection layer 26c. The first to third connection layers 26a to 26c and the first to third cavitation resistant layers 34a to 34c are formed of the same material and the same film thickness. Accordingly, the first to third connection layers 26a to 26c and the first to third cavitation resistant layers 34a to 34c can be simultaneously formed in the same process.

  Inspecting whether different inks are mixed in the liquid discharge head 1 is performed as follows. First, a step of filling the first liquid path 24a with the first liquid, the second liquid path 24b with the second liquid, and the third liquid path 24c with the third liquid is performed. Accordingly, the first anti-cavitation layer 34a is in contact with the first liquid, the second anti-cavitation layer 34b is in contact with the second liquid, and the third cavitation layer is in contact with the third liquid.

  Here, it is assumed that the first liquid path 24a and the second liquid path 24b communicate with each other. Although the communication part is not limited, a joint part (adhesive layer 27) between the support substrate 15 and the support member 13 is considered as one of the communication parts. In other words, when the joint is not sufficiently joined, the first liquid and the second liquid may be mixed through the joint (broken line 28). Since the insulating property of the ink is relatively low (because the ink itself has conductivity), the first cavitation-resistant layer 34a and the second cavitation-resistant layer 34b are electrically connected to each other through the ink communication portion. To do. As a result, the first pad 21a and the second pad 21b are electrically connected.

  In this state, a step of measuring electrical characteristics between the first pad 21a and the second pad 21b is performed. Actually, it is preferable to measure the electrical characteristics between the external connection pad 14 connected to the first pad 21a and the external connection pad 14 connected to the second pad 21b. When ink communication occurs, a change appears in the electrical characteristics between the first electrode pad 21 and the second electrode pad 21. For example, when a constant voltage is applied between the first electrode pad 21 and the second electrode pad 21, a current flows between the first electrode pad 21 and the second electrode pad 21, and therefore there is no communication. The current value increases and the electrical resistance decreases. When a constant current is applied between the first electrode pad 21 and the second electrode pad 21, the voltage between the first electrode pad 21 and the second electrode pad 21 is reduced as compared with the case where there is no communication. , Electrical resistance decreases. When the first electrode pad 21 and the second electrode pad 21 are conductive, no charge is accumulated, so that the capacitance value between the first electrode pad 21 and the second electrode pad 21 decreases. As an alternative method, a time change (time differential waveform) or an accumulated value (time integration waveform) of current, voltage, electrical resistance, and capacitance may be measured.

  In actual inspection, it is preferable to select two pads sequentially from the first to third pads 21a to 21c and measure the above-described electrical characteristics. That is, electrical characteristics between the first pad 21a and the second pad 21b, electrical characteristics between the second pad 21b and the third pad 21c, and between the third pad 21c and the first pad 21a. Electrical characteristics are measured sequentially.

  Thus, according to the present embodiment, the first electrode pad 21a electrically connected to the first anti-cavitation layer 34a and the second electrode electrically connected to the second anti-cavitation layer 34b Electrical characteristics with the pad 21b are measured. Unlike conventional techniques, it is not necessary to draw an evaluation pattern by ejecting ink or pressurize or depressurize a liquid path, so that it is possible to perform highly reliable and efficient color mixing inspection. A liquid discharge head is manufactured through these steps.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. The parts whose description is omitted are the same as those in the first embodiment. FIG. 6A shows a perspective view of a part of the liquid discharge head of this embodiment. A plurality of element substrates 111 a to 111 f are provided along the longitudinal direction x of the support substrate 115. In the present embodiment, six element substrates are provided, but the number of element substrates is not limited. The electrical wiring member 112 is bent along the long side 115 a of the support substrate 115. The electrical wiring member 112 includes a plurality of external connection pads 114 that are electrically connected to the outside of the liquid ejection head. Compared with the first embodiment, the present embodiment has a longer dimension in the x direction parallel to the ejection port array, and can be suitably used for an elongated full line type liquid ejection head.

  FIG. 6B is a plan view of the liquid discharge head of this embodiment. Each of the element substrates 111a to 111f has the same configuration as that of the element substrate 11 described in the first embodiment except that inks of four colors of cyan, magenta, yellow, and black can be ejected. Accordingly, each of the element substrates 111a to 111f includes the first to fourth discharge ports, the first to fourth heating resistance elements, the first to fourth liquid supply paths, and the first to fourth pressure chambers. And first to fourth conductive layers (first to fourth anti-cavitation layers) and first to fourth pads. FIG. 6B shows only the first anti-cavitation layer 134a.

  The support substrate 115 has first to fourth common flow paths 129a to 129d. The first common flow path 129a communicates with the first liquid supply paths of all the element substrates 111a to 111f. The second common flow path 129b communicates with the second liquid supply paths of all the element substrates 111a to 111f. The third common flow path 129c communicates with the liquid supply paths of all the element substrates 111a to 111f. The fourth common flow path 129d communicates with the fourth liquid supply paths of all the element substrates 111a to 111f. The first liquid flows from the ink tank through the first liquid channel of the support member into the first common channel 129a of the support substrate 115. Part of the first liquid flowing through the first common flow path 129a flows into the first liquid supply path of the element substrate 111a on the most upstream side along the direction P in which the liquid in the first common flow path 129a flows. However, the other part flows into the first liquid supply path of the next element substrate 111b located on the downstream side thereof. In this way, the first liquid flowing through the first common flow path 129a sequentially flows into the first liquid supply paths of the plurality of element substrates 111a to 111f. The same applies to the liquid flowing through the second to fourth common flow paths 129b to 129d. In the present embodiment, the first pressure chambers and the first liquid supply paths of all the element substrates 111a to 111f, the first common flow path 129a of the support substrate 115, and the first liquid flow path of the support member are provided. A first liquid path is configured. The same applies to the second to fourth liquid paths.

In the present embodiment, the first anti-cavitation layer 134a of the element substrate 111f on the most downstream side along the direction P in which the liquid in the first common channel 129a flows is electrically connected to the first pad 121a. . Similarly, the second to fourth cavitation resistant layers of the element substrate 111f on the most downstream side along the direction P in which the liquid in the second to fourth common flow paths flows are the second to fourth pads 121b to 121b, respectively. 121d is electrically connected. The first to fourth cavitation resistant layers connected to the first to fourth pads 121a to 121d may be the first to fourth cavitation resistant layers of any one of the element substrates, and the most downstream element substrate. It is not limited to 111f 1st-4th anti-cavitation layer.
Also in the liquid discharge head 1 of the present embodiment, it is possible to perform an ink color mixture inspection as in the first embodiment. Since the liquid supply passages and pressure chambers of all the element substrates 111a to 111f communicate with each other through the common flow path, it is possible to detect any of the element substrates 111a to 111f where communication between the liquids occurs. . A liquid discharge head is manufactured through these steps.

  In each embodiment described above, the conductive layer is an anti-cavitation layer, but the conductive layer is not limited to this. As long as the first to fourth conductive layers constitute at least part of the wall surfaces of the first to fourth liquid paths, the first to fourth conductive layers may be layers different from the anti-cavitation layer.

DESCRIPTION OF SYMBOLS 1 Liquid discharge head 18a-18c 1st-3rd discharge port 20a-20c Heat-generation resistive element 21a-21c 1st-3rd pad 24a-24c 1st-3rd liquid path | route 34a-34c 1st-3rd Conductive layers (first to third anti-cavitation layers)

Claims (5)

A substrate, and a plurality of element substrates provided on the substrate,
Each element substrate communicates with a first discharge port that discharges the first liquid, discharges a first liquid path through which the first liquid flows, and a second liquid different from the first liquid. Energy for discharging to the first liquid and the second liquid path that is in communication with the second discharge port and through which the second liquid flows and that is adjacent to the first liquid path through an adhesive layer. A first heat generating resistive element that imparts energy, a second heat generating resistive element that imparts energy for ejection to the second liquid, and a first part constituting at least a part of the wall surface of the first liquid path. And a second conductive layer that forms at least a part of the wall surface of the second liquid path and is electrically independent of the first conductive layer, and is electrically connected to the first conductive layer. a first pad connected, and a second pad electrically connected to the second conductive layer, was perforated,
The substrate includes a first common flow path that communicates with the first liquid path of all the element substrates, and a second common flow path that communicates with the second liquid path of all of the element substrates. Have
The first conductive layer of any one of the element substrates is electrically connected to the first pad, and the second conductive layer of any one of the element substrates is electrically connected to the second pad. Connected to the liquid ejection head.   2. The liquid ejection head according to claim 1, wherein the first conductive layer is a layer that covers the first heating resistor element, and the second conductive layer is a layer that covers the second heating resistor element. 3.   A conductive first connection layer electrically connecting the first conductive layer to the first pad, and a conductive first connection layer electrically connecting the second conductive layer to the second pad. The liquid discharge head according to claim 1, comprising two connection layers. Filling the first liquid into a first liquid path communicating with a first outlet for discharging the first liquid;
A step of second to discharge port communicating with, filling the second liquid to the second liquid path adjacent to the first liquid path through the adhesive layer for discharging the second liquid,
A first pad electrically connected to a first conductive layer constituting at least a part of the wall surface of the first liquid path; and a second pad constituting at least a part of the wall surface of the second liquid path. And measuring the electrical characteristics between the second pad electrically connected to the second conductive layer electrically independent from the first conductive layer. Manufacturing method of the discharge head. The liquid discharge head includes a substrate and a plurality of element substrates provided on the substrate,
Each element substrate includes the first liquid path, the second liquid path, the first conductive layer, and the second conductive layer,
The substrate includes a first common flow path that communicates with the first liquid path of all the element substrates, and a second common flow path that communicates with the second liquid path of all of the element substrates. Have
The first conductive layer of any one of the element substrates is electrically connected to the first pad, and the second conductive layer of any one of the element substrates is electrically connected to the second pad. The method of manufacturing a liquid ejection head according to claim 4 , wherein the liquid ejection head is connected to the liquid ejection head.

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