wtm@neoucom.UUCP (Bill Mayhew) (05/18/88)
Hi, I just wanted to add a couple of extra things to the discussion of the HP Desk Jet printer that I posted last week. Here are a couple of additional things I've noticed. 1. There are a number of extensions for margin control that the manual notes "are not a feature of level III PCL". 2. There are three methods for downloading a raster image. One is to just load the bit pattern. The second lets a repeat pattern be downloaded. The third permits a mix of image and repeats. There are also a couple of not a feature of level III PCL escape sequences for setting the right margin of the raster area, etc. 3. There are apparently no macros available, as can be found in the Laser Jet PCL. 4. The <Esc> * c line drawing, gray fill and predefined patterns are not available on the Desk Jet. Boo! I miss them. I can understand why, though. It would be a little tough to support the <Esc> & a cursor positioning stuff and have to roll the paper backwards all over the place. Since it takes a couple of seconds for the ink to dry, you'd risk getting ink all over the paper feed pinch rollers and hence all over your paper too. Of course, if the Desk Jet had a megabyte of RAM, then it could compose the image before printing... but then it would need to have a higher horsepower CPU and that RAM costs $$$ these days; simply not compatible with the idea of a relatively inexpensive printer. By the way, the Desk Jet's CPU appears to be a Z8 running at 4.00 MHz. There is one large gate array on the control PC board and two large chips on a smaller PC board near the printhead, so there may actaulay be more processing power ther than just the Z8. 5. <Esc> & a is supported for TEXT printing, however. Goodie! Seems to take quite a while (10-15 seconds) mulling over a page with about 150 such cursor positioning sequences before printing starts, though. I really can't gripe, since I don't know of any outher inexpensive printer that has this feature. 6. The owner's manual fails to mention the escape sequence incantations that are necessary to download a font. It also fails to mention how one would design one's own font/typeface. One would hope that this is not considered proprietary. No mention is made as to whether downloadable fonts are compatible with those of the Laser Jet; that would be nice! A 128K (a least) expansion cartridge is needed before you can think about downloading fonts. There are slots for two cartidges of either RAM or fonts. I just wanted to pass the above additions along to augment my original comments. I also want to mention that the Desk Jet really is a pretty good value versus expense. With street prices just a little over $600, the Desk Jet provides very serious competetion for the middle range of 24 pin printers. I should also mention that I was pretty skeptical about the Desk Jet at first since I was familiar with the pretty terrible output from the Thinkjet printer. The Desk Jet delivers fine quality output on ordinary copier or letterhead bond paper. --Bill wtm@neoucom.UUCP
neff@hpvcla.HP.COM (Dave Neff) (05/24/88)
I worked on the DeskJet Epson Emulation cartridge and Landscape cartridge firmware so I could answer a couple points raised. We absolutely did eliminate any PCL level IV features that would require a page formatter or backing up the paper. The poster is quite right that we cannot backup without smearing ink and adding the additional RAM would make our price closer to the low end laser printers. One key advantage the DeskJet technology has over laser printers is the ability to do a page of 300DPI graphics without adding large amounts of RAM. Of course a page of RAM gives other capabilities (area fill, page formatting, etc.) that we also forfeit. We could have added macros and cursor pushes or pops without much problem. We didn't think people would use these features on a non page formatting printer. Were we wrong? Yes, the printer has a Z80 running at 4MHZ with a proprietary IC that handles much of the misc. logic, paper and head movement, and uses DMA transfers to move text commands and graphics data from the internal RAM into the print head. If you are really interested in all the gory details a future HP Journal issue will contain numerous articles about the printer. It will be the October issue I think. Be sure to read the article about the Epson Emulation cartrige :-) As for the download format, one of the reasons we do not support LaserJet soft or hard fonts is due to the fact our fonts are tuned for the inkjet technology. In fact, fonts are designed on a 600x300 dpi grid. We can actually print at 600 dpi horizontally, but at that resolution we can't print consecutive dots. By designing fonts on the 600dpi horizontal resolution we get significantly better print quality than using straight LaserJet fonts. By the way, the DeskJet fonts are modifications of the LaserJet fonts. Also remember LaserJet fonts are about 3 times as expensive ad DeskJet fonts so you wouldn't want us to force people to buy the LaserJet fonts would you? Of course if you already have LaserJet soft or hard fonts it would be nice if they worked in the DeskJet, but sorry they don't. The download format is not proprietary and we are giving it out to independant software vendors upon request. If you are writing an application that would like to exploit our download capabilities give our support line a call (I don't have the number sorry). If you are just curious, you may have trouble getting the info from them. Eventually we will make the download format universally known, but for now we are trying to have some control over that knowledge for marketting reasons. I probably can't say more and probably have said too much. I guess for now you could say we are considering the format to be "semi" proprietary. If anyone wants specific answers to questions about the DeskJet don't hesitate to write. If you have suggestions for future printers using the DeskJet technology I would love to hear from you. Dave Neff ihnp4!hpfcla!hpvcla!neff