Patent ID: 7472988

Claim:
An inkjet liquid storage tank used in an inkjet recording apparatus, wherein the apparatus uses at least one first printing liquid including a polyvalent metal ion and at least one second printing liquid including an anionic compound which is capable of reacting with the metal ion to cause coagulation and thickening if mixed with the first printing liquid, wherein the apparatus comprises: a recording head comprising a plurality of nozzles which fire at least one liquid; and a liquid treatment device comprising a liquid storage tank that recovers the printing liquids fired from the recording head during a non-printing period and stores the printing liquids, wherein a mixture including at least one of the first printing liquid(s) and at least one of the second printing liquid(s) fired from the recording head during the non-printing period is stored in the liquid storage tank, and wherein the liquid storage tank contains a coagulation-thickening preventing agent which is present in the tank before the mixture enters the tank and which prevents the reaction of the metal ion with the anionic compound, the agent being contained in a state which allows the agent to mix with the mixture.