Coating apparatus and image forming system

A coating apparatus connectable to both an image forming apparatus with a first enclosure having an entrance and a sheet feeder with a second enclosure having an ejector, the coating apparatus comprising:

• a coater to coat a recording medium with a treatment liquid;
• a carry-in entrance on one of two exterior wall surfaces, the carry-in entrance to receive the recording medium from the sheet feeder;
• and
• an ejector on another of the two exterior wall surfaces, the ejector to eject the recording medium to the image forming apparatus,
• wherein a position of the carry-in entrance on the one of the exterior wall surfaces aligns with the ejector on said another of the exterior wall surfaces, aligns with
• the ejector of the second enclosure of the sheet feeder, and aligns with the entrance of the first enclosure of the image forming apparatus.