Abstract: Latching apparatus for first and second adjacent swinging doors prevents locking of the first door unless the second door is latched and prevents unlatching of the second door unless the first door is open.

Abstract: Apparatus for effecting a continuous remixing of magnetic toner material for development of an electrostatic latent image wherein a plurality of magnetic developing rollers are positioned with intersecting magnetic force fields for effecting a blanket of development material extending about and between the developing rollers adjacent an electrostatic latent image bearing surface. The apparatus differs from prior practice in that two mixer rollers are positioned on obtuse angular relationship with respect to the bottom one of the development rollers, with magnetic orientation and hand of rotation such that an orbital magnetic field is created above the mixer rollers in space, lifting all magnetic toner material out of the normal sump area and causing a mixing action and metering action of the development material.