I have been updating the PWG's Finishings specification (PWG 5100.1) to produce Finishings 2.1. One of the additions in this update is the ability for the Printer to state the limits it has on the number of sheets that can be finished. The original Finisher MIB (RFC 3806) has a simple "maximumSheets" attribute that can be used to specify the maximum for the finisher unit itself. We had originally thought that adding a corresponding keyword to "printer-finisher" would be a sufficient solution. But after a few discussions internally, it turns out the maximum number of sheets can vary according to the particular finishing operation itself, not simply according to the finisher accessory. As a simple example, the maximum number of sheets a folder can handle may be 5 sheets for the IPP "finishings" type 'fold-half' but may be only 3 sheets for the IPP "finishings" type 'fold-letter' or 'fold-z'.
Originally I had thought that adding a new "xxx-max-sheets" member attribute to each of the sub-collections of finishings-col (e.g. "baling-max-sheets", "folding-max-sheets", etc.) that allows the Printer to indicate the maximum number of sheets supported for that operation. That may be sufficient.
But there is another issue that seems to be overlooked: not all media types are the same thickness. And by simply providing a number of sheets, we aren't considering the media thickness. Consider a situation where you want to do a booklet printing operation, where the outside cover is made from a different media type than the rest of the pages. The number of sheets doesn't accurately help in this calculation.
To solve the media thickness problem (and to add another layer of complexity, unfortunately) another alternative solution would be to add a new "xxx-max-thickness" member attribute to each of the sub-collections of finishings-col (e.g. "baling-max-thickness", "folding-max-thickness", etc.) that allows the Printer to indicate the maximum set thickness supported for that operation. A Client would consider the number of pages, the media types selected (by consulting "media-col.media-thickness"), and the finishing operations, and would accurately be able to decide whether the number of pages was too great, etc.
Now some vendors have constraints between certain finishing operations and the media types, so that the thicknesses are predictable. But that doesn't really help in actually calculating whether the Job as produced by the Printer will meet the user's expectations.
So we have 3 alternatives:
1. Keep the new "printer-finisher" keyword "maxsetsheets"
2. Eliminate "maxsetsheets" and implement "baling-max-sheets", "folding-max-sheets", etc.
3. Eliminate "maxsetsheets" and implement "baling-max-thickness", "folding-max-thickness", etc.
4. Encourage vendors to use constraints between media type and finishing type to limit the range of thicknesses and ignore the thickness issue
Which way(s) should we go with this? We want something that Clients can and will implement, but we also want the limitations of the Printer to be clearly articulated so that the Client implementation can help the User make informed choices, either automatically or manually.
Wireless Architect - Client Software - IPG-PPS
Standards - IEEE ISTO PWG / Bluetooth SIG / Wi-Fi Alliance / NFC Forum / USB IF
Chair, IEEE ISTO Printer Working Group
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