Card printer
A card printer is an electronic desktop printer with single card feeders which print and personalize plastic cards.  In this respect they differ from, for example, label printers which have a continuous supply feed.  Card dimensions are usually 85.60 × 53.98 mm, standardized under ISO/IEC 7810 as ID-1.  This format is also used in EC-cards, telephone cards, credit cards, driver's licenses and health insurance cards.  This is commonly known as the bank card format.  Card printers are controlled by corresponding printer drivers or by means of a specific programming language. Generally card printers are designed with laminating, striping, and punching functions, and use  desktop or web-based software. The hardware features of a card printer differentiate a card printer from the more traditional printers, as ID cards are usually made of PVC plastic and require laminating and punching. Different card printers can accept different card thickness and dimensions.

Process 
The principle is the same for practically all card printers: the plastic card is passed through a thermal print head at the same time as a color ribbon.  The color from the ribbon is transferred onto the card through the heat given out from the print head.  The standard performance for card printing is 300 dpi (300 dots per inch, equivalent to 11.8 dots per mm). There are different printing processes, which vary in their detail:

 Thermal transfer Mainly used to personalize pre-printed plastic cards in monochrome.  The color is "transferred" from the (monochrome) color ribbon onto the card.
 Dye sublimation This process uses four panels of color according to the CMYK color ribbon.  The card to be printed passes under the print head several times each time with the corresponding ribbon panel.  Each color in turn is diffused (sublimated) directly onto the card.  Thus it is possible to produce a high depth of color (up to 16 million shades) on the card.  Afterwards a transparent overlay (O) also known as a topcoat (T) is placed over the card to protect it from mechanical wear and tear and to render the printed image UV resistant.
 Reverse image technology The standard for high-security card applications that use contact and contactless smart chip cards.  The technology prints images onto the underside of a special film that fuses to the surface of a card through heat and pressure.  Since this process transfers dyes and resins directly onto a smooth, flexible film, the print-head never comes in contact with the card surface itself.  As such, card surface interruptions such as smart chips, ridges caused by internal RFID antennae and debris do not affect print quality. Even printing over the edge is possible.
 Thermal rewrite print process In contrast to the majority of other card printers, in the thermal rewrite process the card is not personalized through the use of a color ribbon, but by activating a thermal sensitive foil within the card itself.  These cards can be repeatedly personalized, erased and rewritten.  The most frequent use of these are in chip-based student identity cards, whose validity changes every semester.

Common printing problems
Many printing problems are caused by physical defects in the card material itself, such as deformation or warping of the card that is fed into the machine in the first place. Printing irregularities can also result from chip or antenna embedding that alters the thickness of the plastic and interferes with the printer's effectiveness. Other issues are often caused by operator errors, such as users attempting to feed non-compatible cards into the card printer, while other printing defects may result from environmental abnormalities such as dirt or contaminants on the card or in the printer. Reverse transfer printers are less vulnerable to common printing problems than direct-to-card printers, since with these printers the card does not come into direct contact with the printhead.

Variation in card printers

Card printer types
Broadly speaking there are three main types of card printers, differing mainly by the method used to print onto the card. They are:

Near to Edge. This term designates the cheapest type of printing by card printers. These printers print up to 5 mm from the edge of the card stock.
Direct to Card, also known as "Edge to Edge Printing". The print-head comes in direct contact with the card. This printing type is the most popular nowadays, mostly due to cost factor. The majority of identification card printers today are of this type.
Reverse Transfer, also known as "High Definition Printing" or "Over the Edge Printing". The print-head prints to a transfer film backwards (hence the reverse) and then the printed film is rolled onto the card with intense heat (hence the transfer). The term "over the edge" is due to the fact that when the printer prints onto the film it has a "bleed", and when rolled onto the card the bleed extends to completely over the edge of the card, leaving no border.

Encoding Techniques
Different ID Card Printers use different encoding techniques to facilitate disparate business environments and to support security initiatives. Known encoding techniques are:

Contact Smart Card – The Contact Smart Cards use RFID technology and require direct contact to a conductive plate to register admission or transfer of information. The transmission of commands, data, and card status held between the two physical contact points.
Contactless Smart Card – Contactless Smart Cards exhibit integrated circuit that can store and process data while communicating with the terminal via Radio Frequency. Unlike Contact Smart Card, contact less cards feature intelligent re-writable microchip that can be transcribed through radio waves.
HiD Proximity – HID's proximity technology allows fast, accurate reading while offering card or key tag read ranges from 4” to 24” inches (10 cm to 60.96 cm), dependent on the type of proximity reader being used. Since these cards and key tags do not require physical contact with the reader, they are virtually maintenance and wear-free.
ISO Magnetic Stripe - A magnetic stripe card is a type of card capable of storing data by modifying the magnetism of tiny iron-based magnetic particles on a band of magnetic material on the card. The magnetic stripe, sometimes called swipe card or magstripe, is read by physical contact and swiping past a magnetic reading head.

Software
There are basically two categories of card printer software: desktop-based, and web-based (online). The biggest difference between the two is whether or not a customer has a printer on their network that is capable of printing identification cards. If a business already owns an ID card printer, then a desktop-based badge maker is probably suitable for their needs. Typically, large organizations who have high employee turnover will have their own printer. A desktop-based badge maker is also required if a company needs their IDs make instantly. An example of this is the private construction site that has restricted access. However, if a company does not already have a local (or network) printer that has the features they need, then the web-based option is a perhaps a more affordable solution. The web-based solution is good for small businesses that don't anticipate a lot of rapid growth, or organizations who either can't afford a card printer, or don't have the resources to learn how to set up and use one. Generally speaking, desktop-based solutions involve software, a database (or spreadsheet) and can be installed on a single computer or network.

Other options 
Alongside the basic function of printing cards, card printers can also read and encode magnetic stripes as well as contact and contact free RFID chip cards (smart cards).  Thus card printers enable the encoding of plastic cards both visually and logically. Plastic cards can also be laminated after printing.  Plastic cards are laminated after printing to achieve a considerable increase in durability and a greater degree of counterfeit prevention. Some card printers come with an option to print both sides at the same time, which cuts down the time taken to print and less margin of error. In such printers one side of id card is printed and then the card is flipped in the flip station and other side is printed.

Applications 
Alongside the traditional uses in time attendance and access control (in particular with photo personalization), countless other applications have been found for plastic cards, e.g. for personalized customer and members’ cards, for sports ticketing and in local public transport systems for the production of season tickets, for the production of school and college identity cards as well as for the production of national ID cards.

References

See also 
 Typewriter ribbon
 Dye-sublimation printer
 Smart card

Computer printers
Non-impact printing