| CPC B41J 2/16552 (2013.01) [B41J 2/16535 (2013.01); B41J 2/165 (2013.01); B41J 2002/16558 (2013.01); C11D 3/43 (2013.01)] | 15 Claims | 

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               1. A printing apparatus comprising: 
            an ink jet head configured to eject an ink for printing; 
                a maintenance liquid configured to maintain the ink jet head, the maintenance liquid being aqueous and subject to detection by a conductivity-based sensor, and the maintenance liquid comprising at least one selected from the group consisting of inorganic alkalis and ethylenediaminetetraacetic acid compounds, and at least one selected from the group consisting of organic acids and organic alkalis; and 
                a conductivity-based sensor configured to detect an electrical conductivity of the maintenance liquid, 
                wherein the electrical conductivity of the maintenance liquid is 100 μS/cm or more, and a pH of the maintenance liquid is 6.0 to 11. 
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