Traditional laser print cartridges comprise a drum, a primary charge roller, a toner roller, a recovery blade, a wiper blade, and a waste bin. In order to print, the drum is either positively or negatively charged by the primary charge roller. A laser assembly within the printer is then used to discharge select regions of the drum in order to form the desired image. Toner having a charge opposite that of the drum is then dispersed onto the drum from the toner roller. As paper passes between the transfer roller of the printer and the drum, the toner is applied to the printer paper. As the drum continues to rotate, residual toner and any other debris is removed by the wiper blade. The removed toner and debris is then deposited into the waste bin, while the recovery blade assists in retaining the removed toner and debris within the waste bin.
However, laser print cartridges have been known to defect, resulting in a repetitive and unwanted image being printed down the printer paper. This defect is most commonly caused by the formation of one or more spots on the primary charge roller. These spots are often a result of paper dust, calcium carbonate, or kaolin clay that has not been removed from the drum by the wiper blade. When this debris is not removed by the wiper blade, the debris is compressed between the drum and the primary charge roller and as a result sticks to the primary charge roller. Resultantly, the area of the primary charge roller covered in debris is insulated and will not act to charge the drum as it passes by, thus causing toner to be attracted to the uncharged portion of the drum and creating unwanted toner marks down the page.
This defect is most prevalent in the legal and medical industries, in which heavy bond paper is most often used in place of regular printer paper. Due to the composition of the heavy bond paper, more paper dust is generated when the heavy bond paper passes between the drum and transfer roller as compared to normal printer paper. Because there is an increase in the production of paper dust, there is an increased chance for paper dust particles to pass by the wiper blade and get pressed into the primary charge roller. Resultantly, the increased volume of paper dust particles leads to an increased defect rate in the laser print cartridge.
Therefore it is the object of the present invention to provide an improved laser print cartridge having a paper cleaning assembly. In addition to the paper cleaning assembly, the improved laser print cartridge provides a printing assembly and a primary cleaning assembly. The printing assembly includes a drum, a primary charge roller, and a toner roller for applying toner to printer paper. The primary cleaning assembly includes a wiper blade for removing large particles of debris from the drum, while the paper cleaning assembly includes a wicking flange for removing smaller particles that may pass by the wiper blade. As such, the wicking flange is positioned in between the wiper blade and the primary charge roller and is mounted to the wiper blade. A cleaning portion of the wicking flange is pressed against the drum and acts to remove the residual debris not removed by the wiper blade. Together the drum, the wiper blade, and the wicking flange delineate a waste receiving volume where debris that is removed from the drum by the wicking flange is deposited. Field tests using the present invention have been shown to reduce the printing defect rate from 23.1% to 2.2%.