High-speed monochrome production printers made for a wide range of users, from printing shops / businesses to printing offices and data centers. To meet various needs from on-demand printing, these printers are provided with a high resolution of 1200x4800 dpi, features to handle a wide range of paper, and various post-processing options. In addition, high cost performance and productivity has been realized for them. To minimize downtime, an “operator call light” is installed as standard, which allows users to check the printers from a distance via sound or light.