Ejection liquid and ejection method

Abstract

The ejection liquid of the present invention includes a compound having a guanidine group, and a carboxyl group or a sulfonic acid group in one molecule, and being represented by the general formula (1), or a salt of the compound, for the purpose of stably ejecting a solution including at least one of a protein and a peptide by imparting thermal energy to the solution.

1 - 10 . (canceled) 
     
     
         11 . An ejection method for ejecting a liquid by employing a liquid ejection apparatus comprising a liquid ejection head for ejecting the liquid by a thermal inkjet system, a reservoir for storing the liquid, and a liquid feed path for feeding the liquid stored in the reservoir to the liquid ejection head; comprising
 a step of ejecting the liquid from the liquid ejection head by feeding the liquid stored in the reservoir to the liquid ejection head through the liquid feed path and then imparting ejection energy to the fed liquid,   wherein the liquid comprises at least one kind of a protein or a peptide; at least one selected from the group of a compound having a guanidine group, and a carboxyl group or a sulfonic acid group in one molecule and being represented by the general formula (1), or a salt of the compound; and a liquid medium:   
       
         
           
           
               
               
           
         
         wherein X in the general formula (1) represents an optionally branched alkyl group having one or more and eight or less carbon atoms, and when a side chain branched at X has a functional group or functional groups, the side chain has one or more hydroxyl groups, or carboxyl groups or sulfonic acid groups, and Y represents a carboxyl group or a sulfonic acid group. 
       
     
     
         12 . The ejection method for ejecting the liquid according to  claim 11 , wherein X in the general formula (1) represents an optionally branched alkyl group having one or more and eight or less carbon atoms, and when a side chain branched at X has a functional group or functional groups, the terminal of the side chain has carboxyl groups or sulfonic acid groups. 
     
     
         13 . The ejection method for ejecting the liquid according to  claim 11 , wherein the compound represented by the general formula (1) comprises one or two or more compounds selected from the group consisting of 2-guanidinoacetic acid, 3-guanidinopropionic acid, 4-guanidinobutanoic acid, α-guanidinoglutamic acid, guanidinomethanesulfonic acid, 2-guanidinoethanesulfonic acid, 3-guanidinopropanesulfonic acid, and the salts of these. 
     
     
         14 . The ejection method for ejecting the liquid according to  claim 11 , wherein the liquid further comprises a surfactant. 
     
     
         15 . The ejection method for ejecting the liquid according to  claim 11 , wherein the surfactant is a polyoxyethylenesorbitan fatty acid ester. 
     
     
         16 . The ejection method for ejecting the liquid according to  claim 11 , wherein a driving frequency for driving the liquid ejection head is 0.1 kHz or higher and 100 kHz or lower.