Three color laser printers make fast color printing almost affordable
Tom Thompson
At first, laser printers dealt with matters simply in black and white. Color laser printers arrived but commanded prices of $50,000 or more, unaffordable to all but those who made their business working with color. QMS changed this situation dramatically last year by introducing the ColorScript Laser 1000 (see ``QMS Strikes with Color Laser Printer,'' July 1993 BYTE). Using a new, 300-dots-per-inch Hitachi print engine to lay down colored toners on plain paper, and costing just $12,499, the ColorScript Laser 1000 started the affordable desktop color laser-printer business.
Not resting on its laurels, QMS introduced this June its second-generation 600-dpi color laser printer, the QMS Magicolor Laser Printer, with a price
starting at $9999. With sufficient memory, it can generate 600- by 600-dpi output. QMS reduced the ColorScript Laser 1000 price to $7999. However, two other vendors also launched color laser printers with prices starting under $10,000. Also in June, Xerox introduced its 4900 Color Laser Printer, starting at $8495. Its controller modulates the imaging laser, so that the output can be 300, 600, or 1200 dpi along the horizontal axis (and 300 dpi vertically). And in September, Hewlett-Packard announced its HP Color LaserJet printer. Its output is only 300 dpi, but pricing starts at $7295, and the HP entry features a simplified print engine that improves color print quality.
Thus, the opening shots in the war for the nascent desktop color laser-printer market have been fired. These printers offer quality and per-page costs competitive with the best ink-jet printers but with laser-printer speed and networking capabilities. The battle will heat up as other vendors, such as Tektronix (see the text box ``Tektro
nix Threatens a Show Stealer''), enter the fray and trade blows on features and price. For this review, I evaluate the new printers from the current combatants in this market: HP, QMS, and Xerox.
Color Laser Basics
As a group, color laser printers are big and heavy. Initial setup is more complex than that of a typical laser printer, because there are now four colors of toner (cyan, magenta, yellow, and black) rather than one.
For the QMS and Xerox printers, you have to add four toner cartridges plus four developer modules, a waste box, and a small oil bottle. The HP printer combines the color developers into one unit, minimizing the number of items that you install to two (the black toner has a separate developer unit). However, you must still add toner power to four hoppers inside the printer.
The QMS Magicolor and the Xerox 4900 use versions of the same Hitachi print engine, although each company had the engine designed to its own specifications. This engine uses a rotating OPC (orga
nic photoconductor) belt to receive a page image and transfer it to the print drum one hue at a time. The amount of electrostatic charge on the belt, which is controlled by the laser beam, determines how much one of the four process colors adheres to the OPC belt on each rotation.
After four belt rotations, the print drum holds the complete four-color image. This composite image is then transferred to a sheet of paper or transparency. It's important to note that the QMS Magicolor and its predecessor use the same Hitachi print engine. This allows QMS to offer a $2499 controller board swap that brings the ColorScript 1000 up to Magicolor capabilities.
The Konica print engine used in the HP Color LaserJet forgoes the OPC belt and lays the toners down directly on the print drum. This improves color registration, because it eliminates a belt that can stretch or contract during the printing process. It also rids the printer of one more consumable item, because the OPC belt wears out over time and must
be replaced. However, the print drum still must rotate four times to assemble a complete page image, so the Konica engine operates at about the same speed as the Hitachi engine.
Considering the four-step printing process, you'll find engine speed impressive for all three units. Speed ratings are given in pages per minute, rather than the minutes per page you expect from other color-printing technologies. According to their respective vendors, the QMS Magicolor is rated at 2 ppm for color and 8 ppm for black and white, the Xerox 4900 is rated at 3 ppm for color and 12 ppm for black and white, and the HP Color LaserJet is rated at 2 ppm for color and 10 ppm for black and white.
QMS Magicolor Laser Printer
The $8495 QMS list price nets you a printer with a basic configuration of 12 MB of RAM and enough memory to produce black-and-white output at 600 dpi and color output at 300 dpi. By carefully controlling the Hitachi engine's stepper motor and laser beam, QMS has coerced true 600-dpi resolutio
n out of a 300-dpi mechanism. A $10,999 version with 28 MB of RAM can produce both color and black-and-white output at 600 dpi. You can expand RAM up to 64 MB using SIMMs. An Intel 80960CF processor running at 33 MHz handles the printer's rasterizer and operating system.
The QMS Magicolor has one unique feature: the QMS Crown operating system, a multitasking operating system that scans all ports for incoming data and identifies the network protocol and PDL (page-description language) for each print job. The operating system boots from an internal 80-MB hard drive (upgradable to 120 MB), and it can spool multiple jobs to this drive. This setup enables the QMS Crown operating system to manage and process several print jobs at once, minimizing bottlenecks in receiving jobs from the network. Because the printer's intelligence is stored on the hard drive, it allows field upgrades of the operating system and the PDL emulations.
The QMS Magicolor provides an RS-232 serial port and a parallel port that
supports the IEEE 1284 bidirectional protocol. A DB-25 SCSI port lets you connect up to six external hard drives that can cache frequently used typefaces or act as spool buffers. For networking, a mini-DIN-8 LocalTalk port is standard, but you can add an optional Ethernet interface card ($650) that supports a single Ethernet connection ($149)--either thin, thick, or 10Base-T. A Token Ring interface ($999) is also available. A daughterboard installed on the controller board determines the Ethernet protocols supported. The review unit could handle NetWare, EtherTalk (AppleTalk), TCP/IP, and LAN Manager/LAN Server simultaneously.
The QMS Magicolor supports PostScript level 2 plus HP's PCL5 (Printer Control Language) and GL/2. It uses its own PostScript clone interpreter and has 65 resident PostScript typefaces. Two external cartridge slots let you add extra typefaces or another PDL.
Xerox 4900 Color Laser Printer
The Xerox 4900 and the QMS Magicolor use the same print engine. The basic Xerox 490
0 has 12 MB of RAM, letting the printer produce 300- by 1200-dpi output for black-and-white pages. Color output at 300 by 1200 dpi requires 24 MB of RAM. Memory is expandable to 48 MB. The printer's controller uses an AMD 29030 RISC processor operating at 25 MHz.
The controller can boost the engine's horizontal resolution to 1200 dpi through laser modulation. The printer uses a Xerox patented digital halftoning technology called Quad Dot. By using the 1200-dpi resolution to split halftone cells into quadrants and selectively applying pixels to each quadrant during the halftoning process, the resulting patterns trick the eye into seeing more gray levels. This translates into more apparent colors on the page, while minimizing halftoning artifacts.
The 4900 has a DB-9 serial port, a Centronics parallel port, and a LocalTalk port. An optional Ethernet interface costs $649 and provides thinnet and 10Base-T connectors. A Token Ring interface is also available for $849. The Ethernet interface supports
NetWare, EtherTalk, and TCP/IP. The Xerox 4900 doesn't have a SCSI port.
The printer provides Adobe's PostScript level 2 interpreter (version 2013.115) and HP's PCL5 and GL/2. It has 55 resident fonts (35 PostScript, 13 Intellifonts, and seven bit-mapped). The controller automatically scans the I/O ports and senses the PDL of incoming print jobs.
HP Color LaserJet Printer
The basic HP Color LaserJet configuration has 8 MB of RAM. For PostScript work, you'll need a minimum of 12 MB of RAM. Memory is expandable to a maximum of 72 MB by adding extra RAM SIMMs. The HP Color LaserJet controller uses an AMD 29030 RISC processor operating at 20 MHz. HP's Resolution Enhancement Technology smoothes the edges of black text and graphics but not with color images.
A quick glance at the back of the HP Color LaserJet reveals one of HP's cost compromises: A Centronics bidirectional parallel port is the only interface. Obtaining any other type requires the purchase of an HP JetDirect board for the pri
nter's MIO (Modular I/O) slot. Several versions are available--a LocalTalk and Ethernet version ($429), an Ethernet-only version ($369), and a Token Ring version ($619). Two cartridge slots let you add extra typefaces.
The only native PDL supported in the HP Color LaserJet printer is HP's PCL5. An Adobe PostScript level 2 interpreter (version 2013.114) is available as an option for $795. The interpreter is stored on a ROM SIMM that mounts in one of the RAM SIMM sockets. Because the PostScript SIMM occupies a memory socket, you can expand printer RAM to only 56 MB with PostScript.
The HP Color LaserJet has 45 resident typefaces (35 Intellifont and 10 TrueType) plus another 35 PostScript typefaces when using the PostScript option. The printer also has a built-in TrueType rasterizer within the PCL5 and PostScript emulations. Like the other printers, the HP Color LaserJet's controller scans the I/O ports and switches PDLs automatically (if PostScript is present).
Blazing Colors
I gave all
three printers a workout on BYTE's network and experienced no problems. Each ran the BYTE PostScript test without a hitch, also. This test rates the speed of a printer's PostScript interpreter (see the table ``Performance Results'').
To gauge performance with applications, I used Genoa Technology's PostScript printer tests. Genoa creates tests to evaluate PDL emulation compatibility, and, in fact, QMS uses these suites to test the compatibility of its PostScript clone. Genoa generously loaned me a set of color ATSes (application test suites) for evaluation with these printers. The tests consist of captured PostScript output from a variety of real-world applications, such as Microsoft Excel, Adobe Illustrator and Photoshop, Lotus 1-2-3, QuarkXPress, Aldus PageMaker, Frame's FrameMaker, and others. Because the test suites are captured PostScript, you can download them directly to a test printer without incurring overhead from a graphical operating system or an imaging engine.
The Genoa tests consi
sted of four groups, each representing a specific application category. Group 1 consisted of 13 pages of spreadsheet output composed of charts and graphs. Group 2 consisted of 26 pages of CAD, desktop publishing, and drawing-application output with a mixture of bit maps, text, graphics, and shaded surfaces. Group 3 consisted of 14 pages of word processing and database output composed mostly of text, with a smattering of graphics. Group 4 consisted of two pages of scanned images. Although the QMS and Xerox printers support higher resolution modes, I set both to operate at 300 dpi to make valid comparisons with the 300-dpi HP printer.
The printers' output speed averaged around 1 ppm, which is not bad, considering that the tests closely resembled real-world output and made heavy use of color. However, for scanned images, the output performance plummeted to about 4 minutes per page, due to the mass of data that has to be processed in a scanned image.
The QMS, with its 33-MHz processor, usually came
in first. Oddly, the HP, with a 20-MHz AMD 29030, generally bested the Xerox 4900, which uses the same processor but clocked at 25 MHz. As expected, the HP and Xerox printers, which use genuine Adobe PostScript, had no difficulty printing the Genoa application test files. Neither did the QMS Magicolor. It speaks well of the QMS PostScript clone that it printed the complex and varied images in the Genoa tests without a hitch.
All three printers produced handsome output. There were imperfections, however. The color wheel generated by the BYTE PostScript test (see the figure ``BYTE PostScript Color Wheel'') showed noticeable banding on the QMS Magicolor, even at 600 dpi, and slight banding on the HP Color LaserJet at 300 dpi. The dithering patterns on the QMS output, however, were much less obvious. No banding was detectable on the color wheel produced by the Xerox 4900, due to the dithering pattern its Quad Dot Technology created. On the QMS and Xerox printers, transitions from colored regions to black r
egions showed darker colored bands, an artifact of the Hitachi engine. Be aware that the BYTE PostScript test deliberately stresses a print engine's color gamut with wide color variations and color extremes, so you won't normally see these transition bands.
The QMS Magicolor and Xerox 4900 showed their best on this test when allowed to operate at the highest resolution. At 300 dpi, the HP Color LaserJet showed clean, crisp images, due to its direct-to-drum Konica print engine. However, when it came to scanned images, the QMS Magicolor and Xerox 4900, operating at higher resolutions, prevailed. When I set Photoshop to do no halftoning and to use the printer's default halftoning screens instead, I obtained gorgeous image output on these two printers.
Cost Conscious
Although color graphics output isn't as striking as that of comparably priced dye-sublimation printers, price per page is an order of magnitude lower. All three printers feature smart use of consumables: The less color you use in a d
ocument, the lower the cost per page. Comparisons of the cost per page for these printers are difficult, because the vendors tally up the costs of consumables differently. Estimates range from about 11 cents per page to 26 cents per page for a document with 15 percent color coverage (equivalent to a company cover letter embellished with a pie chart), and from about 48 cents per page to $1.37 per page for 100 percent page coverage.
The cost is more than that for black-and-white output, but its not so steep that you can't mass-print attractive color brochures and snazzy reports for special jobs. In fact, the cost of black-and-white output for these printers is close enough to conventional laser printing (estimates are from 2.5 cents per page to just over 4 cents per page) that the vendors claim they can stand in for black-and-white laser printers. This isn't exactly true, with the cost per page for black-and-white printing on most lasers at around 2 cents, but you won't break your department's budget if
you accidentally print a report on one.
The printer you should get depends on the work you do. The HP Color LaserJet sports the lowest price, but be aware that this was achieved by shaving certain features from the printer. If you agree with HP on these design decisions, this is the printer for you. If your work consists of text mixed with graphics, and you don't need PostScript, the HP fits the bill admirably. However, if you're using page-layout applications that speak only PostScript, you'll have to add the PostScript option to the HP or look at one of the other printers.
Recall that the basic QMS Magicolor and Xerox 4900 provide minimalist network support through 230.4-Kbps LocalTalk. Nevertheless, adding similar features to the HP Color LaserJet still makes it the lowest-priced printer by the time you tally up the memory and network options the other printers require. However, if your work has lots of scanned images (perhaps real estate brochures), the superior image-handling capabilities o
f the QMS Magicolor and the Xerox 4900 are well worth considering. If your work requires resolutions higher than 300 dpi, the QMS Magicolor and the Xerox 4900 are the only game in town. Any company doing heavy-duty color production with lots of jobs and different typefaces should consider the QMS Magicolor because of its SCSI hard drive option and the QMS Crown operating system.
The Facts
HP Color LaserJet $8832
(as reviewed, with 12 MB of RAM, PostScript,
and Ethernet/LocalTalk capabilities)
Hewlett-Packard Co.
Direct Marketing Organization
P.O. Box 58059
MS 511L-SJ
Santa Clara, CA 95051
(800) 752-0900
fax: (800) 333-1917
QMS Magicolor Laser Printer $11,798
(as reviewed, with 28 MB of RAM and an Ethernet setup)
QMS, Inc.
1 Magnum Pass
Mobile, AL 36618
(800) 523-2696
(205) 633-4300
fax: (205) 633-4866
Xerox 4900 Color Laser Printer $10,093
(as reviewed, with 24 MB of RAM and
an Ethernet setup)
Xerox Office Document Systems Div.
80 Linden Oaks
Rochester, NY 14625
(800) 275-9376, ext. WT4900
(716) 256-4446
Figure: BYTE PostScript Color Wheel
-- HP Color LaserJet
-- QMS Magicolor
-- Xerox 4900
All three printers produced handsome output with the BYTE PostScript color-wheel image (part of the image shown here full size). Each output sample was generated at the printer's highest resolution: 300 dpi for the HP Color LaserJet, 600 dpi for the QMS Magicolor, and 300 by 1200 dpi for the Xerox 4900. The HP printer showed little banding at 300 dpi, compared with the 600-dpi QMS unit, but had a more noticeable dithering pattern. The Xerox 4900 produced no detectable banding, due to the dithering pattern its Quad Dot Technology created.
Illustration: Graph: Performance Results
The QMS Magicolor, with its 33-MHz processor, easily came in first on most tests. Oddly, the HP Color LaserJet, with a 20-MHz AMD 29030, generally bested the Xerox 4900, which uses the sam
e processor but clocked at 25 MHz. The BYTE PostScript test measures general PostScript processing capability. The four Genoa Technology test suites test performance with actual application output: Group 1, spreadsheet; Group 2, CAD, desktop publishing, and drawing; Group 3, word processing and database; and Group 4, scanned images. Start-up time is how long it takes each printer to boot and warm up.
Photograph: The new breed of color laser printers, from left to right: the Xerox 4900, the QMS Magicolor, and the HP Color LaserJet.
Tom Thompson is a BYTE senior technical editor at large with a B.S.E.E. degree from Memphis State University. He is an Associate Apple Developer and author of Power Macintosh Programming Starter Kit (Hayden Books, 1994). You can contact him on AppleLink as T.THOMPSON or on the Internet or BIX at
tom_thompson@bix.com
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Low-Cost Color Lasers
