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Lexmark T640

Lexmark T640

General Laser Printer Information


This article covers the following topics:

  • Preparing paper for loading
  • General paper/media recommendations
  • Proper label selection and usage
  • Ensuring proper print quality
  • Proper maintenance of the printer

Preparing Paper for Loading

Preparing the paper before loading it into the printer will help reduce the chances of the paper jamming.

1Flex the paper back and forth to help separate the sheets.
2Gently fan the pages to help separate the edges.
3Straighten the edges of the stack before loading the paper into the printer.

General Paper/Media Recommendations

  • Always use new undamaged paper.
  • Always use paper designed for use in laser printers.
  • Never use paper that was cut or trimmed by hand.
  • Never mix media sizes, weights, or types in the same tray.
  • When using perforated paper, always ensure that an ironed “laser-perf” or “micro-perf” (about 30 perforations per inch (1.1811 perforations per mm)) is used.
  • Always store media where the temperature is 65° to 75° F.
  • Always store media where the relative humidity is 40% to 60%.
  • Always store media in its original packaging.
  • Always store media on a clean, flat surface.
  • Certain types of media, such as carbonless paper, rough-textured media, or labels prone to adhesive contamination, are not recommended.

Proper Label Selection and Usage

Use the recommended oily fuser wiper when applicable. For monochrome laser printers, two oily fuser wipers are packaged with the label toner cartridge. One should be installed with the new toner, and one should be installed about halfway through the life of the toner. Generally, use of the oily fuser wiper is not recommended if a duplex option is installed on the printer. Refer to the printer’s documentation to verify. NOTE: The duplex option allows the printer to print automatically on the front and back of the page. When considering what labels to use, keep in mind that any label should be able to withstand the heat and pressure applied by the printer’s fuser assembly. Accordingly, use only labels marked for “Laser Printers”. In addition, please be aware that some types of labels are not supported on some printer models. There are many labels to choose from. When choosing labels, please consider the following:

  • Use only labels with characteristics recommended in the Lexmark Card Stock and Label Guide. Click here to view the Card Stock and Label Guide online.
  • Ensure that the adhesive used to fix the label to the liner will not ooze into the printer, causing contamination.
  • Ensure the proper peel strength so that the labels will not dislodge from the liner and stick in the printer.
  • Test a small quantity of labels to ensure proper feed reliability and print quality before purchasing a large amount.
  • Refer to the printer’s documentation to see what types of labels are supported.

Ensuring Proper Print Quality

Listed below are several steps you can take to reduce the likelihood of visible print defects. NOTE: Use of appropriate media as well as proper maintenance of the printer will generally ensure high-quality print. However, environmental factors, printer issues, as well as other variables may also affect print quality.

  • Replace toner cartridges and photoconductor (PC) drums as recommended with original Lexmark parts.
  • Replace maintenance items (including a maintenance kit) as recommended with original Lexmark parts.
  • Use of non-Lexmark parts (i.e. refurbished, remanufactured, or “compatible”) supplies is not recommended as Lexmark cannot ensure their quality. Click here for more information.
  • Periodically inspect the inside and outside of the printer for visible dust and debris. Clean as necessary with a dry, lint-free cloth. Excess toner build-up can be cleaned using the static-charged cloth which is packaged with new toner cartridges.
  • Regularly-spaced repeating marks or areas of missing print (voids) generally indicate a dirty roller. The spacing of the marks or voids should correlate to the circumference of a roller. The printer’s documentation should help in identifying and cleaning rollers.

Proper Maintenance of the Printer

When used properly and in the proper environment, your printer should only require maintenance at the predefined intervals. Refer to the printer’s documentation for more details. Maintenance items on most printers are customer-installable and do not require a service call. The following are generally considered maintenance items:

  • Fuser Assembly
  • Charging Roller
  • Transfer Roller
  • Toner Cartridge
  • Photoconductor (PC) Drum
  • Paper Pick Rollers
Your printer may have one or more maintenance kits that are recommended at regular page intervals. Generally a maintenance message will display on the printer’s operator panel when it is time to install a maintenance kit. These messages do not indicate a printer failure. Environmental and usage factors that may affect the frequency with which you have to perform maintenance include, but are not limited to, the following:
  • The use of unsupported media
  • The use of non-Lexmark parts or supplies
  • Excessive dust in the environment
  • Temperature extremes
  • Humidity extremes
  • Improper handling
  • The use of media that is more strenuous to the printer, such as heavy labels or cardstock
  • Any prolonged use that is outside of what Lexmark recommendsNOTE: These issues can also affect the printer's warranty. Click here to view the general Lexmark warranty statement.

More Information

Click here for a printable reference sheet (DOC file, size: 146 KB). This document is intended to provide some general helpful information about successfully using and maintaining your printer. For assistance beyond what is covered here, please consult the documentation originally included with your printer, such as the User’s Guide and the Quick Reference Guide . If your documentation is lost or damaged, you can find these manuals online. Please visit the Lexmark Publications page and select your printer.


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