Method for manufacturing liquid ejection head and liquid ejection head

Abstract

A method for manufacturing a liquid ejection head includes selectively exposing a first photosensitive resin layer to light, thereby curing the portion of the first photosensitive resin layer defining a flow channel member; forming a second photosensitive resin layer on the first photosensitive resin layer; selectively exposing the second photosensitive resin layer to light, thereby curing the portion of the second photosensitive resin layer defining an ejection opening member; and removing the unexposed portions of the first and the second photosensitive resin layer at one time with a developer. Before removal with the developer, the water absorption W of the intermediate layer, the water absorption W1 of the exposed portion of the first photosensitive resin layer, and the water absorption W2 of the exposed portion of the second photosensitive resin layer satisfy the relationship W≥W1>W2.

What is claimed is: 
     
         1 . A liquid ejection head comprising:
 a substrate;   a flow channel member overlying the substrate and defining a flow channel through which a liquid flows;   an ejection opening member overlying the flow channel member and defining an ejection opening through which the liquid is ejected; and   an intermediate layer between the substrate and the flow channel member,   wherein water absorption W of the intermediate layer, water absorption W1 of the flow channel member, and water absorption W2 of the ejection opening member satisfy the relationship: W>W1>W2.   
     
     
         2 . The liquid ejection head according to  claim 1 , wherein the water absorptions W, W1, and W2 satisfy the relationship W>W1>W2. 
     
     
         3 . The liquid ejection head according to  claim 1 , wherein the water absorption W1 of the flow channel member is 2 to 5 times as high as the water absorption W2 of the ejection opening member. 
     
     
         4 . The liquid ejection head according to  claim 1 , wherein the water absorption W of the intermediate layer is 2 times or less as high as the water absorption W1 of the flow channel member.