Liquid supply device, liquid jetting system, printing system, and liquid circulation method

A liquid jetting system using a first liquid and a second liquid, the liquid jetting system comprising:

• a first liquid jetting head that jets a first liquid which has particles dispersed in a solvent and has a particle sedimentation characteristic different from that of the second liquid and in which the particles are likely to be sedimented;
• a first liquid supply device that supplies the first liquid to the first liquid jetting head and includes a first circulation flow passage which communicates with a circulation port of the first liquid jetting head and communicates with a supply port of the first liquid jetting head a first pressurization device that pressurizes the first liquid inside the first circulation flow passage;
• a second liquid jetting head that jets the second liquid;
• and
• a second liquid supply device that supplies the second liquid to the second liquid jetting head and includes a second circulation flow passage which communicates with a circulation port of the second liquid jetting head and communicates with a supply port of the second liquid jetting head and a second pressurization device that pressurizes the second liquid inside the second circulation flow passage;
• an ink determination unit configured to determine whether a liquid to be circulated is the first liquid or the second liquid;
• at least one processor;
• and
• at least one memory that stores a command to be executed by the at least one processor,
• wherein the at least one processor is configured to
• control the first pressurization device to pressurize the first liquid in a case in which the first liquid is circulated by using the first circulation flow passage, and
• in a case in which the ink determination unit determines that the first liquid is circulated, set a target pressure based on the determination and apply, to the first liquid, a pressure that is equal to or more than 2.0 times and equal to or less than 3.5 times a pressure to be applied to the second liquid in a case in which the second liquid is circulated by using the second circulation flow passage.

A printing system that executes printing using a first ink and a second ink, the printing system comprising:

• a first ink jet head that jets a first ink which has particles dispersed in a solvent and has a particle sedimentation characteristic different from that of the second ink and in which the particles are likely to be sedimented;
• a first ink supply device that supplies the first ink to the first ink jet head and includes a first circulation flow passage which communicates with a circulation port of the first ink jet head and communicates with a supply port of the first ink jet head, and a first pressurization device that pressurizes the first ink inside the first circulation flow passage;
• a second ink jet head that jets the second ink;
• a second ink supply device that supplies the second ink to the second ink jet head and includes a second circulation flow passage which communicates with a circulation port of the second ink jet head and communicates with a supply port of the second ink jet head and a second pressurization device that pressurizes the second ink inside the second circulation flow passage;
• an ink determination unit configured to determine whether an ink to be circulated is the first ink or the second ink;
• at least one processor;
• and
• at least one memory that stores a command to be executed by the at least one processor,
• wherein the at least one processor is configured to
• control the first pressurization device to pressurize the first ink in a case in which the first ink is circulated by using the first circulation flow passage, and
• in a case in which the ink determination unit determines that the first ink is circulated, set a target pressure based on the determination and apply, to the first ink, a pressure that is equal to or more than 2.0 times and equal to or less than 3.5 times a pressure to be applied to the second ink in a case in which the second ink is circulated by using the second circulation flow passage.

A liquid circulation method of, via a liquid supply device that supplies a liquid to a liquid jetting head, circulating a liquid from a circulation port of the liquid jetting head to a supply port of the liquid jetting head by using a circulation flow passage that communicates with the circulation port and communicates with the supply port, the liquid circulation method comprising:

• causing a computer to
• in a case in which the liquid is circulated by using the circulation flow passage, control a pressurization device to pressurize a liquid inside the circulation flow passage,
• control an ink determination unit to determine whether the liquid circulated in the circulation flow passage is a first liquid or a second liquid, wherein the first liquid has particles dispersed in a solvent and has a particle sedimentation characteristic different from that of the second liquid and the particles are likely to be sedimented, and
• in a case in which the ink determination unit determines that the first liquid is circulated as the liquid, set a target pressure based on the determination and apply, to the first liquid, a pressure that is equal to or more than 2.0 times and equal to or less than 3.5 times a pressure to be applied to the second liquid in a case in which the second liquid is circulated.