How do card printers work?

Plastic card printers are printers specialised in printing to rectangular plastic substrates. The most popular card printers use a process called thermal transfer and are used to put text or an image onto a card.  While there are several types of thermal transfer they all involve heating up small elements in a print head, and heating the film and directly fusing the ink on the ribbon with the card. The other printing processes are called Dye Sublimation (Dye Sub) and Reverse Transfer Dye Sublimation.

Card Printing Technology

There are 3 main methods of printing to plastic cards, which are;

  1. Direct to Card (DTC) – Resin / Wax
  2. Direct to Card (DTC) – Dye Sublimation
  3. Reverse Transfer (Re-transfer) – Dye Sublimation

Direct to Card Printing

DTC printing is the process by which a thermal print head is lowered onto the ribbon, and pushes the ribbon into contact with the card.  The print head then heats up the ribbon, and in the case of colour printing turns the ribbon to gas, which sublimates into the surface of the card (dye-sublimation).  For this process to work well, the card needs to be made of laminated PVC, as Laminated PVC  at a microscopic level contains many grooves for the ink to sublimate.  When printing in black (or other single colour) the ribbon is typically a wax resin, that is melted onto the card.  This process is a little more forgiving on the card surface, though still performs best on PVC.

Reverse Transfer Printing

Re-Transfer card printing is similar to Direct-to-Card, except it involves a carrier layer which is hot rolled (laminated) onto the card.   In this process, the print head heats and transfers the ribbon in a mirror image of the required printing onto a clear film (re-transfer film).  The film is made from polyester and is a near perfect receptor, which means all required ink is transferred to a crisp, bright, rich image.  The re-transfer film is then rolled onto the card via a heated rubber roller.  The spring in the rubber ensures, bumps, grooves and depressions are no issues as the film is laid down faithfully onto the card.

How Big is an ID Card?

While there are several sized identification cards that can be printed depending on the card printer, the main size is often referred to CR-80, ID-1 or credit card sized. This is the most popular due to the convenience of being able to store the card in a wallet.  The standardised size of plastic Identification cards has been defined by ISO/IEC 7810:2003 – Identification cards — Physical characteristics

ID-185.60 × 53.98mmMost banking cards and ID cards
ID-2105 × 74mmFrench and other ID cards; Visas
ID-3125 × 88mmPassports
ID-00025 × 15mmSIM cards

Despite the ISO specifically defining card size names, the industry still widely uses historical card size names, with the most common the CR-80 Size (ID-1).

Other card sizes not defined by the ISO include CR-79,  (83.9mm x 51mm) which is slightly smaller than a CR-80 card with the original use as a self-adhesive card which would attach to a CR-80 size “clamshell” or non-printable card often used in Access control. This was a common practice, due to both the high cost of the clamshell access control card, and the ability to make it reusable, and because printable versions of the access control cards were not readily available until the last 10-15 years.

With the advent of low costs “printable” proximity and smart cards in recent years CR-79 use has been in significant decline.