An output apparatus comprises: a plurality of interface sections for inputting data which is supplied from an upper apparatus such as a host computer; an input buffer section to store the input data; an analyzing section for analyzing the input data and for forming predetermined image data; and an output section such as a laser beam printer or the like for outputting or printing the image data. The output apparatus further includes a judging section for judging whether the data inputted from which one of the plurality of interface sections should be deleted, a deleting section for deleting by a predetermined method the data of the input buffer section in which the data to be deleted has been stored, and a notifying section to notify the interface which is deleting at present to the operator. When the designated interface section differs from the interface section which is printing at present, it is judged that the data in the input buffer section should be deleted. When the designated interface section coincides with the interface section which is printing at present, the data in both of the input buffer section and the data storing section to store the image data is deleted.
A print job can be identified without the print data of the print job being analyzed, and print data for a print job that is selected, e.g., print data stored in an input buffer, can be invalidated. In addition, the cancellation of a print job can be designated in real time. To achieve the above object, a host computer and a printer are interconnected via a communication medium. The host computer comprises job packet generation means for adding a header to print data to form a packet for each print job that is generated. The printer comprises job detection and registration means for detecting the start and end of a print job in accordance with the contents of the header of a packet received from the host computer, and for registering the print job in a database.
In two-way communication with a host apparatus, when packet data is received, a packet protocol is used, and when nonpacket data is received, a nonpacket protocol is used. Control is performed so that the destination of each data in the received data is switched between a printing-data buffer storage and a control-command buffer storage depending on whether or not the packet protocol is to be used.
Trace information showing a fact that an illegal output request has been issued from any one of data processing apparatuses is managed. Under an output environment such that an output apparatus is shared from a plurality of data processing apparatuses, when it is detected that a kind of data received by a CPU is specific data such that an output is legally limited, information to identify a transfer source side of the specific data or the received data is preserved and managed in a RAM or the like.
Trace information showing a fact that an illegal output request has been issued from any one of data processing apparatuses is managed. Under an output environment such that an output apparatus is shared from a plurality of data processing apparatuses, when it is detected that a kind of data received by a CPU is specific data such that an output is legally limited, information to identify a transfer source side of the specific data or the received data is preserved and managed in an RAM or the like.
A print job can be identified without the print data of the print job being analyzed, and print data for a print job that is selected, e.g., print data stored in an input buffer, can be invalidated. In addition, the cancellation of a print job can be designated in real time. To achieve the above object, a host computer and a printer are interconnected via a communication medium. The host computer comprises job packet generation means for adding a header to print data to form a packet for each print job that is generated. The printer comprises job detection and registration means for detecting the start and end of a print job in accordance with the contents of the header of a packet received from the host computer, and for registering the print job in a database.
