How Printers Manage Power States and Sleep Timers

A method for printers to intelligently decide whether to reset their sleep timer based on the type of network activity they encounter.

What it covers

This patent describes a power management system for printers that operate across four distinct power states. The system uses a timer to track how long the device has been in a low-power state (the third state) before it should shut down completely (the fourth state). The clever part is how it treats the timer when the printer wakes up partially: if the printer wakes up for a major task, like printing a document, it resets the timer. However, if it wakes up for a minor network inquiry that it cannot fully process, it keeps the original timer running, ensuring the printer still shuts down on schedule.

What it doesn't cover

• —Does not cover power management systems that only use two or three power states.
• —Does not cover devices that reset their sleep timer regardless of the type of network packet received.
• —Does not cover power state transitions that are triggered by physical buttons rather than network events.

The clever bit

The system distinguishes between 'meaningful' wake-up events and 'inconsequential' network pings, choosing to reset the sleep timer only for the former.

Why it matters

In large office environments, printers are often left on 24/7. This patent helps balance the need for energy efficiency (shutting down when idle) with the need for availability (waking up for actual print jobs). By ignoring 'noise' or minor network pings, the device avoids unnecessary energy consumption while remaining ready for actual work.

Real-world examples

• 1.Canon office laser printers
• 2.Network-connected multifunction office copiers