Systems and methods for extracorporeal processing of blood or other body fluid for the treatment of conditions, such as sepsis, autoimmune disease, or toxemia related to kidney failure, liver failure, or drug overdose are provided. Interconnection allows transfer of a fluid between the openings. By merely attaching the starter 2 to the transmission mechanism block 1 with a small number of parts, an accurate positioning of the anchoring bracket 22 with respect to an actuation point 1a is realized, thereby, a positional accuracy between the intermediate anchoring point position and the actuation point 1a can be improved. A density correction processor performs a density correction process on the target pixel by adding or subtracting the density correction value to or from the target pixel or the nearby pixel. The housing surrounds the LED chip and the conductive lead, and has opening recess exposing the LED chip and a part of the conductive lead.