To provide an image forming device capable of detecting irregularities by monitoring communication condition and communication content between the image forming device of a combined machine or the like and a computer, and using both a laser printer and an LED printer as a printer.

A recording means for forming an image of image data with a specified type on a paper, a timing signal forming means for forming a timing signal for controlling action of the recording means based on a specified horizontal synchronizing signal, and an image data forming means for forming the image data with a type appropriate to the recording means based on the inputted image data and transmitting the image data to the recording means based on the horizontal synchronizing signal, are provided.