Patent Grant
8534798
1. Field of the Invention
The present invention relates to an ink jet recording head mounted on an ink jet recording apparatus that performs recording operation by discharging ink.
2. Description of the Related Art
Generally, an ink jet recording head mounted on an ink jet recording apparatus, which performs recording operation by discharging ink, includes a recording element substrate having a discharge port array of a plurality of discharge ports. The recording can be performed at higher speed when the length of the discharge port array is longer.
In such circumstances, in recent years, there has been a growing demand for ink jet recording heads, for example, with a recording width of 4 to 12 inches, which meet the demand for high-speed printing of fine images. However, if a recording element substrate with a long discharge port array is used, the possibility of the problems described below is increased.
Generally, in addition to the discharge port array, a recording element substrate includes recording elements (e.g., electrothermal conversion elements) of a great number that corresponds to the number of the discharge ports. Thus, when the recording elements are arranged on a single recording element substrate, the recording element substrate will be very long. As a result, the possibility of a crack or warpage of the recording element substrate is increased.
Japanese Patent Application Laid-Open No. 2007-296638 discusses an inkjet recording head that can solve such a problem. The inkjet recording head includes a plurality of recording element substrates arranged in an array. According to this configuration, an ink jet recording head of a long recording width is realized without using a single long recording element substrate.
The recording element substrate H2010 and the electric wiring member H2020 of the ink jet recording head H2000 are secured to the supporting member H2030. Further, as illustrated in
The material of the recording element substrate H2010 is silicon, and its coefficient of linear expansion is approximately 3 ppm. The material of the electric wiring member H2020 is resin, and its coefficient of linear expansion is approximately 10 to 30 ppm. The material of the supporting member H2030 is alumina, and its coefficient of linear expansion is approximately 7 ppm.
When a change in temperature occurs due to a recording operation or change in environment, the recording element substrate H2010, the electric wiring member H2020, and the supporting member H2030 of the ink jet recording head H2000 expand/contract in the lengthwise direction of the supporting member H2030 (direction of the arrow A100 in
At this time, since the coefficient of linear expansion of the electric wiring member H2020 is greater than the coefficient of linear expansion of the recording element substrate H2010, a difference in the amount of expansion/contraction of the components is generated. As a result, the wire H1303 is pulled and the possibility of a breakage of the wire H1303 is increased. If the wire H1303 is broken, the recording element substrate H2010 will not be able to receive electric signals and power and, consequently, ink is not properly discharged. Thus, the breaking of the wire H1303 results in poor image quality.
The present invention is directed to a method useful for improving reliability of an electric connection of an ink jet recording head having a plurality of recording element substrates arranged in an array.
According to an aspect of the present invention, an ink jet recording head includes a supporting member, a plurality of recording element substrates secured to the supporting member while being arranged along a lengthwise direction of the supporting member and including a discharge port configured to discharge a droplet and an electrode formed at an end in the lengthwise direction and receives an electric signal that controls the discharge of the droplet from the discharge port, an electric wiring member secured to the supporting member and including a plurality of device holes configured to individually expose the plurality of recording element substrates and an electrode terminal formed in the periphery of the plurality of device holes in the lengthwise direction to transmit the electric signal to the electrode, and a wire configured to connect the electrode and the electrode terminal. The electric wiring member is at least discontinued between the device holes adjacent to each other in the lengthwise direction.
According to the present invention, when a temperature change occurs, since the electric wiring member is discontinued between the device holes adjacent in the lengthwise direction of the supporting member, the amount of expansion/contraction of the electric wiring member between the device holes can be reduced compared to when a conventional electric wiring member is used. Thus, the difference between the amount of expansion/contraction of the electric wiring member and the amount of expansion/contraction of the recording element substrate between the device holes is reduced. Further, since the wire that connects the electrode of the recording element substrate and the electrode terminal of the electric wiring substrate is less prone to breaking, reliability of the electrical connection between the recording element substrate and the electric wiring substrate is increased.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
In this specification, “recording” is to form an image, a design, a pattern, or the like, in addition to a character or a figure, on a recording medium or to process a medium regardless of whether the formed image, the design, the pattern, or the like is visualized so as to allow a user to visually perceive it.
Further, in this specification, various types of “recording media” can be used for recording so long as they can be printed with ink. The recording media include, for example, a cloth, a plastic film, a metal sheet, glass, ceramics, wood, and leather.
The terms “ink” or “liquid” should be widely construed as is with the “recording” described above, and includes all types of liquid used for recording. The “ink” is a liquid that is applied to a printing medium to form an image, a design, a pattern, or the like, or to process the printing medium. Further, the “ink” is a liquid used for ink processing (e.g., solidification or insolubilization of a color material in ink applied to the recording medium).
An ink jet recording apparatus M4000 illustrated in
An ink jet recording head H1000Bk discharges black ink contained in an ink tank H1800Bk. An ink jet recording head H1000C discharges cyan ink contained in an ink tank H1800C. An ink jet recording head H1000M discharges magenta ink contained in an ink tank H1800M. An ink jet recording head H1000Y discharges yellow ink contained in an ink tank H1800Y. An ink jet recording head H1000LC discharges light cyan ink contained in an ink tank 1800LC. An ink jet recording head H1000LM discharges light magenta ink contained in an ink tank H1800LM. The ink jet recording heads H1000Bk to H1000LM (simply referred to as an ink jet recording head H1000 below) are carried by a carriage M4100 and discharge an ink droplet according to an input electric signal.
The ink jet recording head H1000 includes discharge port arrays corresponding to a width of a recording medium K1000. Regarding the recording performed by the ink jet recording apparatus M4000, the recording medium K1000 is moved in the longitudinal direction (the direction of the arrow in
The ink jet recording head H1000 illustrated in
The discharge direction of an ink droplet of the ink jet recording head H1000 according to the present invention is perpendicular with respect to the recording element. This type of recording head is called a side-shooter type recording head. As illustrated in
First, the configuration of the ink supply unit H1002 will be described.
The ink supply member H1500 is formed, for example, by resin molding. The ink supply member H1500 includes a common liquid chamber H1501, which serves as a flow path, and also a Z direction reference plane H1502. The Z direction reference plane H1502 is used for positioning the recording element unit H1001 when it is fixed to the ink supply unit H1002. Further, the Z direction reference plane H1502 serves as a reference plane of the ink jet recording head H1000 in the height direction.
Further, the ink supply unit H1002 includes an ink supply port H1504 through which the ink supplied from the ink tank H1800 flows in. The joint rubber H1700 is provided at the ink supply port H1504. The joint rubber H1700 prevents evaporation of the ink from the ink supply port H1504.
The ink supply tube H1802, which extends from the ink tank H1800, is connected to the ink supply member H1500 by a needle H1801, which is provided at the end of the ink supply tube H1802, piercing the joint rubber H1700. The ink contained in the ink tank H1800 of the ink supply unit H1002 flows into the common liquid chamber H1501 via the ink supply tube H1802. The ink in the common liquid chamber H1501 flows out to the recording element unit H1001.
Next, securing processing of the recording element unit H1001 to the ink supply member H1500 will be described referring to
First, an opening portion of the ink supply member H1500 and the recording element unit H1001 are sealed by a sealing compound H1503. Accordingly, the common liquid chamber H1501 is hermetically sealed. At this time, a Z direction reference plane H1206 of the recording element unit H1001 abuts the Z direction reference plane H1502 of the ink supply member H1500.
A portion where the Z direction reference plane H1206 abuts the Z direction reference plane H1502 is clamped by a screw H1900. In this manner, the recording element unit H1001 is secured to the ink supply member H1500. The sealing compound H1503 is desirably a sealing compound, which is ink resistant and flexible.
After the recording element unit H1001 is secured to the ink supply member H1500, the recording element unit H1001 is bent along the side of the ink supply member H1500 so that an input terminal H1301 is secured to the back side of the ink supply member H1500 (see
Next, the configuration of the recording element unit H1001 will be described.
The silicon substrate H1108 includes an ink supply port H1101, which is a long channel-like port serving as an ink flow path. An electrothermal conversion element H1102, which is a recording element, is provided on either side of the ink supply port H1101. Further, the silicon substrate H1108 includes the electrothermal conversion element H1102 and electric wiring of, for example, aluminum formed by a film forming technique. The electric wiring is formed at the end of the recording element substrate H1100 and is connected to an electrode H1103. Via the electrode H1103, the electric wiring receives an electric signal and power from the electric wiring member H1300.
Further, a discharge port plate H1110 is provided at the upper portion of the silicon substrate H1108. An ink flow path H1104, a discharge port H1105, and a bubble generation chamber H1107 are formed on the discharge port plate H1110 using photolithography technique. The discharge port H1105 is formed at such a position that it faces the electrothermal conversion element H1102.
Regarding the recording element substrate H1100, the electrothermal conversion element H1102 generates a bubble in the ink that is supplied from the ink supply port H1101 to the bubble generation chamber H1107 according to an electric signal received by the electrode H1103. Due to this bubble, the ink is discharged from the discharge port H1105.
The supporting member H1200 illustrated in
The material that can be used for the supporting member H1200 is silicon (Si), aluminum nitride (AlN), zirconia, silicon nitride (Si3N4), silicon carbide (SiC), molybdenum (Mo), and tungsten (W). The supporting member H1200 has an ink supply port H1201 used for supplying ink to the recording element substrate H1100.
The recording element substrate H1100 is accurately positioned and secured to the supporting member H1200 by an adhesive H1202 so that the ink supply port H1201 faces the ink supply port H1101 of the recording element substrate H1100. The adhesive H1202 is desirably a low-viscosity ink-resistant adhesive that allows thin adhesive layer on the contact face and exhibiting relatively high hardness after cure. In other words, the adhesive H1202 is a thermal curing adhesive having epoxy resin as the main material or a thermal curing adhesive, which can also be cured by ultraviolet. The thickness of the adhesive layer is desirably 50 μm or thinner.
Further, the supporting member H1200 includes an X direction reference plane H1204, a Y direction reference plane H1205, and the Z direction reference plane H1206. These are positional reference planes respectively in the lengthwise direction, crosswise direction, and height direction when the supporting member H1200 is mounted on the ink supply member H1500. Further, since both sides of the supporting member H1200 are polished, the principal surface (see
For example, according to the present exemplary embodiment, the parallelism of the two sides is 10 μm or less. At the back side of the supporting member H1200, there is provided the filter member H1600 used for filtering undesired matter in the ink. The filter member H1600 is secured in such a manner that it covers the ink supply port H1201.
As illustrated in
Further, as illustrated in
Further, the recording element substrates adjacent to each other in a widthwise direction D2 of the supporting member H1200 have a region L where the ends of the discharge port arrays of the substrates overlap each other (see
The electric wiring member H1300 is a resin component that supplies an electric signal for controlling discharge of ink to the recording element substrate H1100. The electric wiring member H1300 is secured to the principal surface of the supporting member H1200 by an adhesive H1203 (see
The electric wiring member H1300 includes a plurality of device holes H1306. Each of the device holes H1306 individually exposes each of the recording element substrates H1100. Further, an electrode terminal H1302 used for transmitting an electric signal to the electrode H1103 is provided in the periphery of a device hole H1306 on the sides in the lengthwise direction D1. Further, the input terminal H1301, which is provided at one portion of the electric wiring member H1300, is connected to the electrode terminal H1302 via the above-described circuit.
The electrode terminal H1302 is electrically connected to the electrode H1103 with a gold or an aluminum wire H1303 as is the electrode terminal of the ink jet recording head H2000 in
As illustrated in
An amount of expansion/contraction ΔL of a member due to temperature change is calculated by multiplying an amount of temperature change ΔT, a coefficient of linear expansion a of the member, and a length L of the member as shown in the following equation (1).
ΔL=ΔT×α×L (1)
Among the factors that define the amount of expansion ΔL, the amount of temperature change is difficult to control, and the coefficient of linear expansion is uniquely determined by the selected member. Thus, according to the present invention, in preventing the breaking of the wire H1303 that occurs due to the difference of the amount of expansion/contraction between the electric wiring member H1300 and the recording element substrate H1100 caused by temperature changes, the opening H1307 is formed so that the length of the electric wiring member H1300 is changed.
In other words, by forming the opening H1307, whose opening width w1 is longer than or equal to the region width W2, between the device holes H1306, which are adjacent to each other in the lengthwise direction of the recording element substrate, the amount of expansion/contraction of the electric wiring member H1300 can be reduced. As a result, since the difference in the amount of expansion/contraction between the recording element substrate H1100 and the electric wiring member H1300 due to temperature change is reduced, the stress of the wire H1303 is reduced. Accordingly, the wire H1303 will be less prone to breaking, and reliability of the electrical connection between the recording element substrate H1100 and the electric wiring member H1300 will be increased.
As the opening width W1 becomes wider than the region width w2, the region that helps reduce the amount of expansion/contraction of the electric wiring member H1300 becomes longer. Accordingly, the effect to prevent the wire H1303 from breaking will be increased. If the opening width W1 is set to be wider than the region width w2, the wiring region enough for the circuit will be provided on the electric wiring member H1300 by not allowing one end of the opening H1307 to extend to the edge of the electric wiring member H1300.
According to the present exemplary embodiment, the opening H1307 is provided at a same distance from the device holes H1306 adjacent to each other in the lengthwise direction D1. The position is determined so that a similar effect is obtained in reducing the difference of the amount of expansion/contraction between the recording element substrate H1100 and the electric wiring member H1300 between the device holes H1306 adjacent to each other.
Further, according to the present exemplary embodiment, the position of the opening H1307 is not limited to the region between the device holes H1306 adjacent to each other. For example, as illustrated in
Further, according to the present exemplary embodiment, the length of the straight line region of the electric wiring member H1300 can be reduced without using the above-described opening H1307. For example, as illustrated in
Further, as illustrated in
Further, by arranging the opening H1307 at a position adjacent to the terminal region H1400, the amount of expansion/contraction in the terminal region H1400 is furthermore reduced. Thus, the difference in the amount of expansion/contraction between the recording element substrate H1100 and the electric wiring member H1300 due to temperature change is furthermore reduced, and the effect to prevent the breaking of the wire H1303 is improved.
Further, as illustrated in
As illustrated in
In this case, an electrode terminal H1310, which is formed at the end of the terminal region H1400, is positioned near the area between the first straight line H1309a and the second straight line H1309b. Thus, the electrode terminal H1310 is affected by the expansion/contraction generated in that region between the straight lines. Since the amount of expansion/contraction of the region is greater than that of the region where the opening H1307 is formed (the region between device holes H1306 adjacent to each other), the difference of the amount of expansion/contraction of the recording element substrate H1100 and the electric wiring member H1300 at the electrode terminal H1310 will be greater than that at other electrode terminals. Thus, the wire H1303 connected to the electrode terminal H1310 is easily broken compared to the wires connected to other electrode terminals.
However, according to the present exemplary embodiment, since one end of the opening H1307 extends to the area between the first straight line H1309a and the second straight line H1309b, the length of the straight region becomes shorter. Accordingly, the difference of the amount of expansion/contraction of the recording element substrate H1100 and the electric wiring member H1300 at the electrode terminal H1310 is reduced. Thus, the wire H1303 connected to the electrode terminal H1310 is less prone to breaking.
Further, according to the present exemplary embodiment, one end of the opening H1307 may be connected to the device hole H1306 to which the opening H1307 extends as illustrated in
Accordingly, the wire H1303 connected to the electrode terminal H1310 is less prone to breaking. Further, since the opening H1307 is connected to the device hole H1306, the encapsulant for encapsulating the gap portion formed between the device hole H1306 and one side of the recording element substrate H1100 can be injected through the opening H1307.
Further, according to the present exemplary embodiment, the length of the straight line region of the electric wiring member H1300 can be reduced without forming the above-described opening H1307 as is with the first exemplary embodiment. For example, a cut portion H1308 may be formed in place of the opening H1307 as illustrated in
In this case also, since one end of the cut portion H1308 extends to the straight line region between the device holes provided on the first straight line H1309a and the device holes provided on the second straight line H1309b, the straight line region can be reduced. Thus, an effect similar to the case where the opening H1307 is formed can be obtained.
Further, as is with the first exemplary embodiment, a recording element substrate, which is shorter or longer in the lengthwise direction D1 than the recording element substrate H1100 illustrated in
Further, according to the present exemplary embodiment, the opening H1307 or the cut portion H1308 may be formed in the region between the end of the electric wiring member H1300 in the lengthwise direction D1 and the terminal region H1400 (see
Further, according to the present exemplary embodiment, not only one end of the opening H1307 can be extended to the region between the first straight line H1309a and the second straight line H1309b but the other end can also be extended.
In other words, as illustrated in
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2009-138184 filed Jun. 9, 2009, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-138184 | Jun 2009 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5734394 | Hackleman | Mar 1998 | A |
| 7533960 | Yasuda et al. | May 2009 | B2 |
| 20100156994 | Shimomura et al. | Jun 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 2007-294847 | Nov 2007 | JP |
| 2007-296638 | Nov 2007 | JP |
| 2008-288536 | Nov 2008 | JP |
| 2009-006560 | Jan 2009 | JP |
| 10-0872212 | Dec 2008 | KR |
| Number | Date | Country | |
|---|---|---|---|
| 20100309258 A1 | Dec 2010 | US |
