Plastic Card Printer
Plastic card printers are used most often to create ID cards, ID badges, and access passes. Ordinary access badges do not need special security features. A backstage pass, for example, is a form of access that probably doesn't require encrypting: a security guard simply looks at the pass, verifies its authenticity, and allows its carrier to walk backstage.
Access passes within an office are a whole other story.
Access passes can be encrypted to allow for automatic access. Let's use a law firm as an example. Within a law firm, there are generally thousands of sensitive documents. Keeping these documents away from prying eyes is essential to the firm's continued success. A partner in the company will have access to certain offices and files that a junior attorney does not have access to. The junior attorney will probably have access to areas where a paralegal is not allowed to go.
The partner, junior attorney and paralegal will all carry ID badges or ID cards that will be used as a form of electronic key (automatic access) by swiping them through a monitor. It's one of the roles of plastic card printers to create automatic access control by printing ID cards or badges encrypted with magnetic striping or barcodes. To find an ID card printer able to make cards fitting your exact situation - for example, one that does encode magnetic stripes ("mag stripes"), or one that can have this functionality added later - it is important to talk to a sales representative who knows the full range of products the marketplace provides.
Plastic Card Printers and Transactions
Plastic card printers can also create ID cards which can be used for transactional purposes. These transactions often occur on factory floors, within universities, and within offices. In these cases, it is common for the employee to carry a plastic card containing a tiny, embedded microprocessor called a "smart chip".
A factory worker with an encrypted ID card of this variety can then use that card to purchase a soda from the vending machine in his break room. Office workers can buy a meal in the corporate cafeteria, or a bag of chips from the office vending machine. Students can use their plastic IDs to buy books, meals and school supplies.