hedrick@ATHOS.RUTGERS.EDU (Charles Hedrick) (04/09/88)
This is a preliminary review of the Diconix Dijit 1/PS printer. This is an ink jet printer designed to compete in the medium-speed Postscript printer market. Diconix was a subsidiary of Kodak formed specifically to do work on ink jet technology. However we understand that the organization has now been merged into Kodak, so the printer may start being called a Kodak Dijit 1/PS. Diconix also produces an inexpensive ink jet printer for PC use. Note by the way that it is crucial to include the /PS. The Dijit 1 (without the /PS) is a printer that apparently emulates a Xerox 2700. Here are the major specs of the Dijit 1/PS: - 300 dots per inch - 20 pages per minute (paper handling -- see below for actual Postscript throughput) - Adobe Postscript board, with the original Laserwriter fonts only, but lots of memory (3 or 4MB) - no Appletalk support. Parallel port may be available, but since the parallel port is unidirection, Postscript can't really use it very well. - prints on both sides of paper (under control of front panel or additional Postscript operators) - ink jet mechanism, with provisions for automatic head cleaning, to avoid the messiness typically associated with ink jets - intended for high volume applications - one ream of paper (500 sheets) in each of input and output hoppers. - low cost (at least for the medium-speed market). I have a feeling it is not much above $10K, though my memory could be wrong on that. The printer looks like a modern copier. The internal design has a minimum of moving parts, and appears rather clean. The user interface is based on English (well, natural language -- you can choose about 5 other languages from the front panel) displays in a 40 by 2 character LCD display. There are 4 buttons below the display that allow it to function as a menu system. Most of the settings get stored in EEPROM, so they are permanent. The LCD display is used well by the Postscript support: it shows the user and job name when a job is active, with the display switching between this display and a count of pages printed in the job. One of the menu options lets you look through the last N Postscript output messages, so you can review errors from the front panel. There are various configuration and test options in the menus. The main issues are print speed and print quality. Print speed is currently about 5 pages per minute even on text. (Actually there isn't that much difference between ASCII text and more complex stuff.) This is silly with an engine that can handle 20 ppm. They will have a 68020-based controller within a month or so. We are already in the queue to get one, and will report on the results. I'd think that should get output speed to a reasonable level. Clearly this printer will go nowhere at the current speed, though our immediate concern was more with ability to handle print volume than with output speed, which is why I decided not to wait for the 68020. Resolution is in fact comparable to that of a 300 dpi laser printer. Some people claim that the output looks "fuzzy". It's possible that under a microscope the dots aren't as precise. But I think that impression comes mostly when the output is held side by side with Laserwriter output, and it's because the output isn't quite as dark black. This appears to be inherent in their implementation of the ink jet process. However there are two other things that can cause actual fuzziness, and which in the first few days gave us an unnecessarily bad opinion of the printer: - it is sensitive to the type of paper. Our default paper for laser printers is a xerographic copier paper made by IPCO. It turns out to be a worst-case paper for this printer. There is visible "bleeding" around the edges of characters. This goes away with other kinds of xerographic paper, e.g. those by Mead and Nashua. As far as I know, this paper is all the same weight, and probably the same price. It all works just fine on our laser printers. - there is a "drying time" constant, which we are currently setting to 2 sec. When it is set to .5 sec., as some of the test menus leave it, certain kinds of output streak. (Just to be sure, we have the burster page set it -- you can adjust it from Postscript.) With the right paper, and the right drying time, it's just fine for almost all output. However I wouldn't use it for graphics with very large black areas. (We use QMS PS 800II's for that.) So why would you want to use such a wierd beast? The reason I got it is that our low-volume printers were eating toner cartridges, and out medium and high-volume printers were all terribly unreliable. I like the QMS PS 800 II's a lot. Their Postscript interpreter is fast enough that it can really drive the Canon engine at 8ppm. And it uses the "heavy duty" version of the engine with bigger paper trays and generally heavier construction. But the cartridges are used up so fast that printing on weekends (when our hardware staff isn't around) is always chancy, and there's a good chance that at any given time a printer will have a cartridge that is far enough along in its life that output won't be that good. We hoped that the Dijit 1/PS would go longer between needing to be fed, and that output wouldn't decline during that time period. So far we don't know when it will need to be fed. We've only printed about 5K sheets, and not seen any change in output quality. When it finally does get hungry, it will be just add ink. (I hate to mention such crass things in this group, but I was also concerned about the cost of all those cartridges.) Our previous attempts at higher-volume printers had all used Xerox XP12 or XP24 engines (Talaris 1200 or 2400 - OEM'ed versions of the QMS 1200 and 2400). They were terribly unreliable. They are full of lots of little cams and gears and other gizmo's, and we could never get them to work reliably. We also found that the font manager software for them was unreliable, and getting worse. The theory was that the Dijit had a lot less to go wrong, and would stand up to use in our environment. (To be fair, I have to say that lots of people find the Xerox XP12 and XP24 to be fine printers. We understand from service people that they are usually great workhorses, but at a small fraction of the sites, they can never be made to work reliably, for no observable reason.) It's obviously too soon for us to know whether the Diconix will do better, but from the design, it certainly looks good. We did have problems initially getting it to bring the print head to the home position after being powered down and up. However once it was in use for a while, things have worked fine. The service people tell us that in general the thing works very reliably when it's used a lot, but if it is idle for too long, it gets lonely. We think the initial startup problem was an example of this. Of course ink jet printers are known for getting the ink jets gummed up when they aren't in use. This did actually happen to us once. The result is a white stripe across the output every inch or so. However there is a built-in print head cleaner, so fixing it was just a matter of pushing a button on the console. We don't expect to have such problems as it comes into production use. Light use just isn't a problem with printers here (except maybe over Christmas - I'm considering having a cron job print something every hour during that vacation). In summary, we think that if they can get the print speed up to 15 ppm or so (and I'd think they could), this will be a good medium-speed printer for general use. You will probably want to pair it with a Laserwriter or QMS PS 800-II for final drafts of certain types. The two-sided output has made a lot of friends for it among our users.