Solid ink

Solid ink is a technology used in computer printers and multifunction devices originally created by Tektronix in 1986. After Xerox acquired the Tektronix Color Printing and Imaging Division in 2000, the solid ink technology became part of the Xerox line of office printing and imaging products. Early offerings focused on the graphic arts industry. The Phaser III product introduced in 1991 cost $10,000 US. As the technology improved and costs were reduced, the focus shifted to office printing environments where quality and cost efficiency are important.

Solid ink technology utilizes solid ink sticks in lieu of the fluid ink or toner powder usually used in printers. After the ink stick is loaded into the printing device, it is melted and used to produce images on paper in a process similar to offset printing. Xerox claims that solid ink printing produces more vibrant colors than other methods, is easier to use, can print on a wide range of media, and is more environmentally friendly due to reduced waste output. The sticks are non-toxic and safe to handle. In the mid 1990s, the president of Tektronix actually ate part of a stick of solid ink, demonstrating that they are safe to handle and presumably, eat. The medium of the ink was (at least at the time) made from food-grade processed vegetable oils.

Current solid ink products are the Xerox Phaser 8560 and 8860 color printers and the Xerox Phaser 8560MFP and 8860MFP color multifunction printers. Being otherwise identical, 8560 and 8860 differ by the shape of the ink stick, and the ink price is set much lower for 8860 model, which is, correspondingly, sold for much higher price.

Xerox introduced the new ColorQube 9200 series of tabloid multifunction device on May 7, 2009. This is the first solid ink multifunction device to be capable of printing up to 12×18″ (Tabloid Extra) or SRA3.[1] In the 1990s, a succession of solid ink printers capable of printing up to Tabloid Extra were introduced, including the Phaser III, the Phaser 300, and culminating with the Phaser 380 in 1997.[2]

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Advantages

Print Quality
Due to the way solid ink printers put the ink onto the page, print quality is considered to be excellent with lively colors. Excellent results can be achieved with low-quality stock, as the wax covers the stock with a glossy surface.
Waste
Because solid blocks of ink are used, there is less waste generated than is with laser printers or inkjet printers, which produce empty ink or toner cartridges, in addition to packaging and packing materials. A loose ink block does not leave any residual cartridge after it is consumed - only a crushable, thin, plastic packing tray and a recyclable cardboard packaging box.
Recycled Paper
Solid ink printers are able to print on many different types and thicknesses of media. They are much less sensitive to changes in media type than are color laser printers.
Compatible supplies
Third-party compatible solid ink [3] blocks are available and may be considerably less expensive than official Xerox supplies. Solid contaminants in ink blocks can clog print head nozzles, and may require costly printhead replacement. For this reason, many third-party ink manufacturers provide a guarantee and will pay for the replacement of a damaged printhead.

Disadvantages

Print Durability 
A page printed on the highest quality print setting can have the ink scraped off rather easily with a fingernail. Lower quality print settings do not pile up as much ink and are more durable but the ink can still scrape off.
Warm-up time 
When the device is cold the first page may take several minutes to print. However, once the printer is warmed up, the time to print the first page is negligible.
Power consumption
The ink must be heated and a large portion of the printing mechanism must be kept at or near the ink's melting point during use. When the printer is in "sleep mode", most units keep a small pool of each color wax within the printhead heated to a temperature just above the ink's "freeze point". According to the Xerox service manual, this consumes about 50 watts.
Excessive Ink Usage 
Every time the printer loses power for long enough to cause the portion of ink which was being kept above its "freeze point" in the printhead to drop below that temperature, the mass of ink in each reservoir would have contracted in size enough as a result of the cooling to permit air to enter the printhead, which would result in print aberrations until the printhead reservoirs had been refilled by the ink melter assembly above it. As a result, the printhead is then purged using a vacuum pump, causing some ink to be flushed from the printhead's holding tanks into the waste tray to remove the air from the printhead. (Xerox printers have a "waste ink" tray for this purpose. Since all four inks are dumped into a unified "waste ink" tray, it is impossible to reuse the lost ink since the four process colors coalesce to form a single solid mass in the tray, which look much like solidified candle wax drippings, but almost black.) If the printer was in its sleep state, less time without power would be required to necessitate a purge cycle than if the printer was in its ready-to-print state (since the printhead is kept much hotter when ready-to-print).
Printer damage from moving
The printer contains melted wax when at operating temperature, and owners' manuals warn that it cannot be moved until it has completed a special cool-down cycle selected from the machine's control panel. Cool down time by merely removing mains power is recommended as 30 minutes, but all modern solid ink printers have a shutdown cycle which use fans to solidify the ink in less than ten minutes, with the added benefit of physically restraining the printhead to prevent damage during moving or shipping. The manuals warn that substantial damage is possible otherwise, requiring servicing by a trained technician if not properly cooled down before moving the printer. Moving the printer before cool down completes can damage the print head by spilling molten ink between reservoirs of different color as well as over other components inside the printer (motors, belts, etc.), and is not covered under maintenance or warranty.
Odor
As the printer must melt wax blocks as part of its warm-up and printing process, the printer will give off a distinctive smell that continues throughout the life of the printer. It smells similar to a mix of hot wax, pine trees, and cedar. This problem has been eliminated in more recent printers due to reformulated ink.
High-speed Moving Parts
In order to transfer the ink to the sheet of paper, the printer includes a large internal drum, which is rotated at a high speed. Over time, the belt that moves the drum may stretch, or other mechanical problems occur, however solid ink printers contain a fraction of the moving parts that a conventional laser printer does.
Clogged Print Heads
Unlike some inkjet printers where the cartridge includes the print head, the print head in these printers is fixed. Over time, parts of the print head become permanently clogged, resulting in unsightly streaks, but there are printhead cleaning cycles which can resolve most printhead issues. Dust caused by the use of cheap paper can cause printhead clogging, which is why Xerox recommends the use of high-quality paper. Printheads have been known to last one million prints or more.
Incompatible with laser printers
Not appropriate for letterhead printing or uses where the document will later be fed through a black/white laser printer. The heat from the laser fuser will cause the wax ink to discolor, fade, or contaminate the laser printer.
Ultraviolet resistance 
Using organic colourants, solid ink prints are sensitive to the sun's ultraviolet light, and color fades with sunlight exposure over time. This problem is the same with inkjet printers dyes, but laser printers are immune to that, using mineral pigment toner.
Solid ink block and maintenance roller compatibility 
Ink blocks are not compatible between Phaser models, due to Xerox changing each CMYK molded shape with each new model release due to changes in the formulation (and especially melt point) of the ink. Special openings prevent the insertion of ink sticks from the wrong model.

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