The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, the approaches described in this section may not be prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Some printing devices are configured with a feature known as “locked printing” to provide control over the printing of electronic documents. When the locked printing feature is enabled and a print job is sent to the printing device, processing of the print job is deferred until a user enters authentication data at the printing device and the authentication data is verified. The authentication data typically includes a user ID and/or password, although many different types of authentication data may be used. A user conventionally enters the authentication data through an operation panel on the printing device and the printing device verifies the authentication data. Once the authentication data is successfully verified, the printing device allows the print job to be processed, i.e., allows a printed version of the electronic document reflected in the print job to be generated.
One of the problems with conventional locked printing approaches is that a user must enter the authentication data using the user interface provided on the printing device. User interfaces on printing devices often include only a simple operation panel with a limited number of status indicators and function buttons. For example, a typical operation panel may include status lights that indicate whether a printing device is in a “ready” state, requires attention or is in an error state. The typical function buttons include buttons for resetting a print job, canceling a print job, turning the printing device online or offline and a “go” button for overriding a warning or error condition. If a printing device includes a display, then the operation panel may also include a menu button and one or more “select” buttons that allow a user to view and navigate through a series of menu options. For example, the select buttons may include “+” and “−” or “<” and “>” buttons for menu navigation. Using these types of function buttons to enter user authentication data in the form of an alphanumeric string tedious and time consuming. Each function button must be associated with multiple characters and therefore entering a character string requires a large number of button presses, which is time consuming and prone to error. This process is further complicated in situations where the character string to be entered includes both upper and lower case characters, since even more button presses are required to represent both upper and lower case characters. Thus, entering authentication data, such as a user ID and password, using the user interface conventionally available on printing devices is tedious and not user friendly. Based on the foregoing, there is a need for an approach for implementing locked printing on printing devices that does not suffer from limitations of prior approaches.