The present invention relates generally to a printing device, and more particularly to a printing device that includes a fuser and fuser heating element.
Printing devices are widely used for creating printed outputs, documents, or pictures, for copying or modifying existing documents, and so forth. Therefore, many types of printing devices are available that generate a printed output, including text, graphics, images, etc.
One type of printing mechanism deposits toner on a sheet of paper and then a fuser component of the printing mechanism heats the toner to fuse the toner to the paper. The toner must be heated to a specific temperature range in order to fuse to the paper. The temperature range is typically about 165 degrees to about 205 degrees Celsius, but may additionally range from 125 to 250 degrees Celsius.
In the prior art, the fuser generally operates at a constant temperature. The prior art may include a fuser temperature control circuit or a processor that monitors the fuser temperature and keeps it at a constant level.
However, there are several drawbacks in the prior art approach. One problem is that the ideal temperature for fusing depends on the amount of toner in the region being fused. The fusing may apply too much heat when fusing a region of heavy toner. Conversely, fusing may apply insufficient heat when fusing a region of light toner. Therefore, the prior art constant temperature approach only works optimally for printing of average toner amountsxe2x80x94a xe2x80x9cone mode fits allxe2x80x9d approach. As a result, the fusing may be uneven and of poor quality. Furthermore, overheating may occur and damage to the fuser may result. One type of damage is cracking of a fusing element.
In some prior art printing devices, the user may set the fuser temperature for different paper sizes and thicknesses. However, such an approach still does not accommodate the amount of toner being fused, i.e., it does not accommodate the image density. In addition, this approach suffers in that it is not automatic and the user may forget to change settings. Moreover, the user may have to learn how to perform a temperature selection, and the selection will take time to enter from the control panel of the printing device.
Therefore, there remains a need in the art for improvements in printing devices.
A printing device comprises a printing mechanism including a fuser heating element and an image analysis device. The image analysis device performs an image analysis on a print job in order to determine an image density of at least a portion of the print job. A fuser heating element temperature is controlled according to the image density.