Abstract: A gear unit comprising a shaft and a gear each having a first axial section and a second axial section. The first axial section features the gear having external teeth with an internal surface that corresponds to an external surface of the shaft. The second axial section includes features in the shaft and gear that engage together. Methods of using the gear unit including positioned the gear on the shaft, and rotating the gear relative to the shaft to engage the gear with the shaft.

Abstract: A toner cartridge included with an image forming device when initially sent to a user. The cartridge has a limited toner capacity. The user is able to print with the small capacity cartridge upon initially receiving the image forming device. Once the toner is exhausted, a second large capacity cartridge having a greater toner capacity can replace the small capacity cartridge. The small capacity cartridge and the large capacity cartridge are constructed in a similar shape to be mounted in the same manner within the image forming device.

Abstract: A toner fill plug for a toner cartridge within an image forming device. The cartridge includes a toner reservoir having a port through which toner is input. The plug is sized to fit within the port and prevent toner leakage. The plug includes a reflector which aligns with an adjacently-positioned toner level sensor for determining the amount of toner remaining within the reservoir. The plug is removable to allow the user to refill the reservoir with new toner.

Abstract: A printing device has paper feed devices upstream and downstream of a printing station. The downstream paper feed devices uses pairs of pressure feed rolls which frictionally feed the paper when received. A tapered guide channel positioned in side by side relation with the pair of feed rolls comprises a stationary guide plate and pivotable guide plate with guide surfaces designed to collapse any curl in the leading edge of single or multilayer paper. A spring maintains the pivoted guide plate in operating position with a predetermined spring force which opposes deflection by the leading edge of the paper but allow deflection due to paper generated forces exceeding the predetermined spring force.