1. Field of the Invention
The invention relates to a method of controlling a printing system that is arranged to process a sequence of media sheets and is operable with a finite number of different settings, the method comprising a step of calculating a time to finish that will be needed for processing the sequence.
2. Background of the Invention
A printing system typically comprises a number of functional components, e.g. one or more print stations and a media management system for timely supplying media sheets, which may be of different types and have different properties, to the print station and for discharging the printed sheets. Some of these components may be capable of operating in different modes which are determined by corresponding setting parameters. For example, the media management system may be set to operate in either a simplex mode or a duplex mode, and/or different colour modes may be available for printing in black only, in a multicolour mode or a full colour mode. When a fuse station is used for fixing an image on the media sheets, different modes of operation may also be distinguished by different operation temperatures to which the fuse station has been set. Depending on settings, different conveying speeds of the media sheets may need to be selected.
US 2002135792 A1 describes a printing system which is capable of calculating and displaying to the user a “time to finish” for a print job that has been entered, so that the user will know in a advance how long she has to wait until her job will be completed. The time to finish is composed of print times which are needed for printing an image on an individual sheet, and of necessary inter-sheet time gaps, i.e. time intervals that separate the end of a print operation for one page from the start of a print operation for the next page. The print times are generally determined by the operating speed of the print station (or stations) and possibly also by the specific contents of the images to be printed. The inter-sheet time gaps must have a certain length in order to prevent the successive sheets from colliding with one another. More extended time gaps may be needed for example when the sheet transport path includes switches for directing the sheets to different destinations. In that case, a time gap of a certain length is necessary for operating the switch after the previous sheet has passed and before the next sheet arrives. Similarly, when the sequence of sheets includes two or more different media types which require specific adjustments of certain functional components, e.g. an adjustment of a print heat or print station, extended time gaps may be needed for making the necessary adjustments. Such extended times may also be referred to as setup times and transition times for transiting between different operational modes.
Naturally, the time to finish will depend upon the mode of operation to which the printing system has been set for processing the job. For example, printing in a duplex mode may take more time than printing in a simplex mode. Conversely, when a higher operating temperature is set for the fuse station, the sheets may pass the fuse station at a higher speed, so that the time to finish will be shortened. On the other hand, if the scheduled sequence of sheets includes a sheet of a media type that does not tolerate the high fuse temperature, a long inter-sheet time gap may be needed in order to adjust the fuse temperature for this sheet. When such events occur relatively frequently in the scheduled sequence, it may be more efficient to leave the fuse station always in a low temperature mode.
US 2010110483 A1 discloses a printing system which can be switched between a simplex mode and an interleaved duplex mode. When the system is in the duplex mode and then a number of simplex copies have to be made, a choice between different possible strategies has to be made. According to one strategy, the duplex loop is emptied first, and then the system is switched to the simplex mode. According to another strategy, the machine is left in the duplex mode and some of the simplex copies are allowed to pass idly through the duplex loop. The cited document proposes an algorithm for minimizing the time to finish for the mixed sequence of simplex and duplex copies.
US 2007/177189 A1 discloses a printing system capable of processing a plurality of job streams and sub-jobs within a stream, wherein a job scheduler determines a schedule for processing queued print sub-jobs of a job stream using a utility function which may aim at optimizing productivity.