This invention defines a medium access protocol for the support of mesh networking in wireless communications. The presence or absence of inoperative nozzles can thus be established without the use of information about the positional relation between the print head and the ink drop detection device, dispensing with the need to align the print head and the ink drop detection device with high accuracy. A purchase amount and a merchant account are identified based on the purchase request. 02,6dec-8-ene, which are useful for the synthesis of neplanocin A having strong antitumor activity. The control assembly includes a cover to prevent damage to the control elements.