Printing system, printing apparatus, and printed-matter production method

An inkjet printing method, comprising:

• applying plasma treatment onto a surface of a print medium to reduce a pH value of the surface of the print medium;
• applying, using a roller, treatment substance that improves fixation of ink to at least the surface of the print medium having undergone the plasma treatment;
• ejecting liquid on the print medium using an ejector;
• detecting wettability of the print medium based on an image of the liquid ejected by the ejector on the print medium;
• and
• performing inkjet recording by discharging ink directly on the treatment substance which is on the print medium having undergone the plasma treatment,
• wherein the treatment substance increases a dot density of the ink on the surface of the print medium.

An inkjet apparatus, comprising:

• a plasma generator to apply plasma onto a surface of a print medium to reduce a pH value of the surface of the print medium;
• a roller to apply treatment substance in a form of a liquid to the surface of the print medium to which the plasma has been applied;
• an ejector to eject liquid on the print medium;
• a detector to determine wettability of the print medium from an image of the liquid elected by the ejector on the print medium;
• and
• a nozzle to directly discharge ink on the treatment substance on the surface of the print medium,
• wherein the wettability of the print medium is determined by a contact angle between the surface of the print medium and the liquid;
• and
• wherein the treatment substance increases a dot density of the ink on the surface of the print medium.