Although they will probably never be small or light enough to please the road warriors who need to tote them around, manufacturers are taking steps to provide printing convenience at minimum weight. Portable printers can weigh anywhere from around 1 to 5 pounds and are just wide enough to accept a standard 8.5-inch-wide piece of paper. They typically come with a battery or a car charger for printing on the go. Some manufacturers are even adding support for printing wirelessly from a cell phone.

There are three basic types of portable printers available... ink-jet, thermal transfer, and direct thermal.

The popular ink-jet type of portable printer uses small cartridges of liquid ink that spray very fine drops of ink on paper. If you plan on doing color printing, you should know that the color cartridges will only last for a few pages. If presentation is important, an ink-jet printer may be your best option as they will generally give a better output than thermal type printers.

Thermal transfer printers use heat and pressure to transfer images from a ribbon to the page. Thermal transfer printers require the use of a specialized, heat sensitive paper. Thermal transfer printers can print color but the quality is usually not good enough for professional presentation and the color ribbons don't last very long - usually producing only a page of color print.

Direct thermal printers are heat-sensitive and operate much like fax machines of 20 years ago. They also require the use of a specialized, heat sensitive paper. Direct thermal printers cannot print in color.

The main advantage of thermal transfer and direct thermal printers is that they can be very small and lightweight - much more so than an ink-jet printer. So if size and weight are your primary concern, this may be the printer for you.

The cost of printing pages from a portable printer is higher than a regular office printer. If you're printing in black, you can expect to pay 5¢ per page for thermal transfer printers, and as much as 11¢ per page for some ink-jet printers. Color printer costs can run about 70¢ per page.

Battery life is also an important consideration. Most printers use Nickel-Cadmium (NiCad) batteries. NiCad batteries can print up to 90 pages, and can usually be recharged while still in the printer. Some printers use Nickel Metal Hydride (NiMH) batteries, which can print as many as 250 pages but take more time to recharge. You may also want to purchase a car-lighter adapter, quick charger, and an additional battery.

Portable printers are more expensive than desk-top models and can range from a low of around $200 for non-color thermal transfer printers to a high of about $400 for a color ink-jet model.

In a pinch, there are alternatives to a portable printer. If your computer has a faxmoden you can fax your file to the nearest available fax machine. Make sure to set the fax transmission on high quality, and try to send to a plain paper fax machine. Many hotels are now making printers available in their lobby for their guests to use.

Electronic mail services can also take care of the printing needs of traveling business people. After modeming your files to an email service, they can be forwarded in three ways: electronically to a recipient's email account, by phone to a fax number, or printed and mailed to a street address.