Patent Application
20150062260
1. Field of the Invention
The present invention relates to a liquid ejection head for ejecting liquid from an ejection opening and a printing apparatus.
2. Description of the Related Art
The printing speed and image quality of an inkjet printer become higher, and accordingly, the density of a liquid ejection head becomes higher. Accordingly, members included in the liquid ejection head become smaller and thinner. Therefore, a substrate and a flow path forming member which are major members included in the liquid ejection head tend to deform because of stress caused by adhesion or the like.
In a case where a flow path forming member deforms, an ejection opening deforms which is formed in the flow path forming member to eject liquid, and it becomes difficult to accurately land liquid at a targeted position on a printing medium. Further, there may occur a problem that the substrate and the flow path forming member peel off.
As a means for suppressing such deformation of the substrate and the flow path forming member, there is a method disclosed in Japanese Patent Laid-open No. 2007-331245. In the method disclosed in Japanese Patent Laid-open No. 2007-331245, at least one slit, groove, or dent is provided on an upper surface of the flow path forming member to relieve stress caused by the volume shrinkage of the flow path forming member, thus suppressing peeling at an interface with the substrate.
As an adhesive for joining the substrate and the flow path forming member, a thermosetting adhesive is used from the viewpoint of ink resistance. The adhesive is heated and cured and the shrinkage stress of the substrate which is generated in a case where the temperature of the substrate is returned to a normal temperature is applied in a direction to pull the flow path forming member. In the method disclosed in Japanese Patent Laid-open No. 2007-331245, grooves are provided on the upper surface of the flow path forming member to prevent deformation and peeling from being caused by stress generated by the volume shrinkage of the flow path forming member.
According to the present invention, there is provided a liquid ejection head comprising: a flow path forming member comprising an ejection opening for ejecting liquid; a substrate comprising the flow path forming member; and a support member for supporting the substrate, the support member being bonded to a surface of the substrate which is opposite to a surface of the substrate on which the flow path forming member is provided, wherein the substrate has, on a side surface thereof, a groove extending along the surface of the substrate which is opposite to the surface of the substrate on which the flow path forming member is provided.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
FIG. 5E1 is a diagram illustrating the process for producing the liquid ejection head;
FIG. 5E2 is a diagram illustrating the process for producing the liquid ejection head;
According to a study of inventors, although the grooves are provided on the upper surface of the flow path forming member disclosed in Japanese Patent Laid-open No. 2007-331245, the flow path forming member disclosed in Japanese Patent Laid-open No. 2007-331245 can deform, and accordingly, the ejection openings can deform and it is difficult to accurately land liquid at a targeted position on a printing medium.
Accordingly, the present invention is directed to providing a liquid ejection head and a printing apparatus capable of performing high-quality printing by suppressing the shrinkage stress of an adhesive joining a substrate and a flow path forming member and the deformation and peeling of the flow path forming member.
A first embodiment of the present invention will be described below with reference to the drawings.
The carriage 200 reciprocates in the main scan direction via the belt 204 according to a rotation direction of the pulley 205 driven by a carriage motor 203. A liquid ejection head 201 is mounted in the carriage 200. The liquid ejection head 201 is a liquid ejection head capable of ejecting liquid, and the liquid ejection head 201 corresponding to inks of four colors is mounted in the carriage 200.
A color image can be printed by mounting, in the carriage 200, a liquid ejection head 201K for a black ink, a liquid ejection head 201C for a cyan ink, a liquid ejection head 201M for a magenta ink, and a liquid ejection head 201Y for a yellow ink.
Incidentally, the word “printing” used in the present specification means not only imparting a character, a figure, or the like to a printing medium, but also imparting an insignificant image such as a pattern.
Further, the word “ink” should be interpreted in a broad sense, and means liquid which serves for formation of an image, a design, a pattern, or the like, processing of a printing medium, or treatment of an ink or the printing medium in a case where the liquid is imparted to the printing medium. The treatment of the ink or the printing medium includes, for example, coagulating or insolubilizing a color material in the ink to be imparted to the printing medium to improve fixing properties, printing quality, color developing properties, image durability, and the like.
The liquid ejection head 6 of the present invention is obtained by bonding, with an adhesive 5, a substrate 1 for the liquid ejection head having energy generating elements 7 (hereinafter simply referred to as “the substrate 1” as well), a flow path forming member 2 formed on the substrate 1 for the liquid ejection head, and a support member 4 forming a flow path and supporting the substrate 1. The flow path forming member 2 has a plurality of through holes penetrating a facing section facing a surface of the substrate 1 for the liquid ejection head on which the energy generating elements 7 are provided.
This flow path forming member 2 is made of a resin material, and the plurality of through holes are collectively provided by using a photolithography technique or an etching technique. The through holes are provided in the flow path forming member 2 so that first openings which are open toward the surface of the substrate 1 for the liquid ejection head on which the energy generating elements 7 are provided communicate with second openings provided on a liquid ejection side. The plurality of through holes are used as ejection openings 3 for ejecting liquid by using energy generated by the energy generating elements 7. These through holes are arranged in lines at a predetermined pitch and form arrays of ejection openings.
It is possible to use electrothermal conversion elements (heaters), piezoelectric elements, or the like as the energy generating elements 7 provided on the substrate 1 for the liquid ejection head. The substrate 1 for the liquid ejection head is made of silicon, and the plurality of energy generating elements 7 are provided in lines at positions of the substrate 1 facing the arrays of the ejection openings and form a plurality of element arrays. An ink supply opening 8 penetrating the substrate 1 for the liquid ejection head is provided between the element arrays to supply liquid to the energy generating elements 7.
Further, the flow path forming member 2 and the substrate 1 for the liquid ejection head are in contact with each other to form ink flow paths 9 in space between the flow path forming member 2 and the substrate 1 for the liquid ejection head. The substrate 1 for the liquid ejection head is provided with connection terminals 10 for supplying power to the energy generating elements 7. The support member 4 is bonded, with the adhesive 5, to a surface of the substrate 1 for the liquid ejection head which is opposite to the surface of the substrate 1 facing the flow path forming member 2. The connection terminals 10 of the substrate 1 are electrically connected, and the energy generating elements 7 are supplied with power to eject liquid.
A slit (a groove or a dent) is provided on the side surface of the substrate 1 to extend along the surface of the substrate 1 bonded to the support member 4, and provided in a side of a surface of the substrate 1 which is opposite to the surface of the substrate 1 facing the flow path forming member 2 as a stress dispersing section 11 which can deform in a case where shrinkage occurs as a result of adhesion of the substrate 1 to the support member 4.
In the conventional structure, the flow path forming member 22 as well as the substrate 21 deforms. In contrast, in the present embodiment, the amount of displacement of an upper portion of the substrate 1 and the flow path forming member 2 can be reduced by forming the stress dispersing section 11 which can deform independently of the side surface of the substrate 1 as shown in
Further, the cross-sectional secondary moment I is represented by I=bh3/12 where b is the width of the cantilever and h is the height of the cantilever. The groove for forming the stress dispersing section 11 is provided at a position to be not in contact with the support member 4. The stress dispersing section 11 deforms to absorb stress on the upper portion of the substrate 1 and the flow path forming member 2. Accordingly, it is preferable that the height h of the stress dispersing section 11 below, and that the length L of the stress dispersing section 11 be long (0<h≦L). It is preferable that the height h of the cantilever be equal to or lower than half of the thickness h′ of the substrate 1. Since stress caused by curing and contraction of the support member 4 is applied to the whole surface of the substrate 1, it is preferable that the stress dispersing member 11 be provided in the whole periphery of the whole sides of the substrate 1. Providing the stress dispersing section, that is, the groove in the whole periphery means that the stress dispersing section is formed throughout the periphery of the substrate.
As shown in
Next, after a wafer is cut into chips by using a dicer or the like, an opening groove is formed on the side surface of the substrate of the present invention to form the stress dispersing section 11 as shown in FIG. 5E1. More specifically, the stress dispersing section 11 is formed by changing the shape of a beveling wheel 12 generally used for machining an outer peripheral portion of a wafer to a convex shape to machine the side surface of the cut substrate 1.
Further, in the method for producing the stress dispersing section 11, a modified layer 14 in which cracks will grow in a case where stress is applied to an end of the substrate may be formed by using a stealth dicing technique and a laser 13 as shown in FIG. 5E2, and the modified layer 14 may be formed so that in a case where stress is applied to the substrate 1, the modified layer 1 crumbles. In the present embodiment, the stress dispersing section 11 is formed to have a height h of 50 μm and a length L of 150 μm.
Further, the size of the cut substrate is 2 mm×20 mm. Next, as shown in
Forming the stress dispersing section 11 on the side surface of the substrate 1 in this manner makes it possible to realize the liquid ejection head capable of performing high-quality printing by suppressing the shrinkage stress of the adhesive bonding the substrate to the flow path forming member and the deformation and peeling of the flow path forming member.
Other embodiments of the present invention will be described below with reference to the drawings. Incidentally, the basic features of the present embodiments are identical to those of the above-described embodiment, and only characterizing features will be described below.
Further, the slit, the groove, or the dent is not necessarily one in number, and may be more than one in number.
Such structures can also produce advantageous results similar to the above-described advantageous results, and can realize the liquid ejection head capable of performing high-quality printing by suppressing the shrinkage stress of the adhesive bonding the substrate to the flow path forming member and the deformation and peeling of the flow path forming member.
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 such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2013-176856, filed Aug. 28, 2013, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-176856 | Aug 2013 | JP | national |
