1. Technical Field
The present invention relates to a liquid ejection head, such as an ink-jet type recording head, a liquid ejection apparatus, and a manufacturing method of a liquid ejection head, and more particularly to a liquid ejection head which includes a channel unit provided with a series of liquid channels extending from a common liquid chamber down to nozzle orifices through pressure chambers and which can discharge liquid in the form of liquid droplets from the nozzle orifices thereof, a liquid ejection apparatus, and a manufacturing method of a liquid ejection head.
2. Related Art
As for liquid ejection heads structured to discharge out liquid droplets from nozzle orifices thereof by causing pressure fluctuation to liquid accommodated in pressure chambers, there are known, for example, ink-jet type recording heads used for image recording apparatuses, such as printers, color material ejection heads used for manufacture of color filters of liquid crystal displays, electrode material ejection heads used for electrode formation of organic electroluminescence (EL) displays and field luminescence displays (FED), and living body organic matter ejection heads used for manufacture of biochips (biotip), etc.
There are various forms of such a liquid ejection head. One exemplary form of the ink-jet type recording head (hereinafter, referred to as a recording head) in an ink-jet type recording apparatus (hereinafter, referred to as a printer) includes a channel unit fixed to a head case, the channel unit having a structure in which a nozzle substrate provided with a plurality of nozzle orifices, a channel substrate provided with a channel section such as pressure chamber cavities or grooves which define a series of ink channels from a common ink chamber down to the nozzle orifices through pressure chambers, and a resilient plate (also called a sealing plate which seals an opening of the channel substrate) which causes elastic deformation to diaphragm sections corresponding to the pressure chambers in response to the operation of a pressure generating means (for example, piezoelectric vibrator) are laminated. Of composition components of the channel unit, the channel substrate is required to be machined at a high density with high precision so as to respond to high density of a recorded image and high speed of recording operation. Accordingly, the channel substrate is suitably made of a crystalline base material such as silicon single crystal base material (silicon wafer) by which a fine shape can be formed by, for example, an anisotropic etching process with sufficient accuracy of dimension.
Accordingly, it is important to assemble the above-described composition components with high positioning accuracy in order to control the discharge operation of the recording head with high precision. Thus, JP-A-2001-30490 discloses a recording head whose composition components are laminated on and combined with each other in the state in which relative positions of all the composition components are specified in a manner such that composition components of a channel unit and a head case are provided with two through-holes which are positioning references and positioning pins are inserted in the two through-holes.
By the way, when a channel substrate is made of a crystalline base material as described above, the through-holes of this channel substrate are formed by etching like pressure chamber cavities. In this case in which there is a difference between the interval of the through-holes of the channel substrate and the interval of the through-holes of the head case, mechanical stress is applied to the channel substrate via the positioning pins due to the difference of the intervals, and thus there was the probability that the channel substrate cracks or breaks.