| 摘要 |
<p>PURPOSE:To prepare an ink which maintains a constant pH and consequently excellent dispersibility and thermal stability for a long period and shows no deposition of solids, by detecting the pH of a solvent for the ink and supplying a pH adjustor. CONSTITUTION:The pH of a solvent 2 in a solvent tank 1 is detected with a pH detector 3 and the detected pH value is sent to a control device 6 via an A/D converter 16 to confirm whether it is within predetermined limits. When the detected pH value is found to be out of the optimum pH range, the control device 6 works to open a valve 9 of a pH adjustor feeder 4 for feeding of a pH adjustor 5 into the solvent 2. When the detected pH value is within the optimum pH range, the control device 6 works to open a discharge valve 15 for feeding the solvent 2 into an ink preparation tank 7 and mixing with an aqueous soln. of dye fed from a dye soln. feeder 10.</p> |
