A print control device that facilitates management of print job. The print control device performs a processing on a print job to generate image data capable of being printed by an image forming device, transmits the generated image data to the image forming device, determines whether or not the data amount of image data that has not yet been printed by the image forming device, among the transmitted image data, exceeds a threshold value, and, in a case where the data amount of the image data that has not yet been printed exceeds the threshold value, holds transmission of image data of a subsequent print job and transmits job information that indicates an attribute of the subsequent print job and does not include image data, to the image forming device.

An image printing apparatus including a communication interface, a printer, a user interface including an operation panel, a controller configured to control the printer and the user interface is provided. The controller is configured to receive preliminary data sent from an information processing apparatus through the communication interface; control the printer to perform a warm-up action; receive job data including image data through the communication interface; control the user interface to perform a receipt-notification and control the printer to start printing based on the image data; during a period from the receipt of the preliminary data until start of receiving the job data, withhold from accepting a cancellation command sent in response to user entering a cancellation operation; and after the start of receiving the job data, accept the cancellation command and cancel printing of the image based on the job data associated with to the entered cancellation command.

Functionality for issuing instructions related to the status of a printing device can be added to a control device capable of connecting to a printing device while suppressing modification of programs installed on the control device. A network system 1 includes a printer 9 that prints on recording media, and a control device 8 capable of communicating with the printer 9. The control device 8 has a control unit that generates and outputs by a printing program a command instructing the printer 9 to print; and a management unit that adds a maintenance command issuing an instruction related to the status of the printer 9 to the command output by the control unit, and sends the command with the added maintenance command to the printer 9, by a maintenance program that is different from the printing program.

An image printing apparatus including a communication interface, a printer, a user interface including an operation panel, a controller configured to control the printer and the user interface is provided. The controller is configured to receive preliminary data sent from an information processing apparatus through the communication interface; control the printer to perform a warm-up action; receive job data including image data through the communication interface; control the user interface to perform a receipt-notification and control the printer to start printing based on the image data; during a period from the receipt of the preliminary data until start of receiving the job data, withhold from accepting a cancellation command sent in response to user entering a cancellation operation; and after the start of receiving the job data, accept the cancellation command and cancel printing of the image based on the job data associated with to the entered cancellation command.

A printing unit comprises: a communication unit configured to be connected to a communication line to which a plurality of print data transmission devices are connectable; a memory unit configured to store print data received by the communication unit; a printing unit including a roller mechanism for sending recording paper and being configured to drive a printing mechanism based on the print data stored in the memory unit to print on the recording paper; and a control unit configured to determine, in response to receiving a connection request from a first print data transmission device by the communication unit, whether or not the printing apparatus is connected to another print data transmission device for communication, cause the communication unit to send as a reply a first response for causing the first print data transmission device to wait to start transmission of print data when the printing apparatus is connected to the another print data transmission device for communication, and cause the communication unit to send as a reply a second response for allowing the first print data transmission device to transmit the print data after the printing apparatus and the another print data transmission device end the communication connection.