Reproduction machine control

In an electrostatic type reproduction apparatus having a photosensitive member on which electrostatic images of an original being reproduced are formed, with means to charge the member in preparation for imaging, exposure means to selectively discharge the member to form thereon electrostatic image of the original, means to develop the image, and transfer means to transfer the developed image to a sheet of copy substrate material, the combination of:

• a source of said copy substrate material including at least two supply trays, at least one of said supply trays being independently adjustable to accommodate different size copy substrate material;
• transport means to advance substrate material from any of said trays to said transfer means for transfer of a developed image thereto;
• control means for operating said apparatus to produce a copy run using copy substrate material from a first of said supply trays, said control means including material monitoring means for monitoring the supply of copy substrate material in said first supply tray, said material monitoring means being operative on a preset low supply of copy substrate material in said first tray to switchover to a second one of said supply trays;
• and
• inhibit means operative to intervene and prevent switchover from said first supply tray to said second supply tray during said copy run when the size of the substrate material in said second supply tray is different from the size of the substrate material in said first supply tray.