Image forming apparatus

A method of forming images on an image-transferring member, comprising:

• providing at least one color cartridge that supplies at least one color toner;
• providing at least one monochrome cartridge that supplies monochrome toner;
• determining whether the at least one color cartridge contains insufficient color toner for printing an image according to a first image job;
• queuing a second image job, the second image job not requiring the at least one color cartridge, before the first image job requiring the at least one color cartridge if the at least one color cartridge contains insufficient color toner for printing the image of the first job;
• and
• forming an image according to the queuing.

An image forming apparatus, comprising:

• at least one color cartridge means that supplies at least one color toner;
• a monochrome cartridge means that supplies monochrome toner;
• an image forming means for forming an image on an image-transferring member using at least one of the at least one color toner and the monochrome toner;
• a processing means electrically coupled to the image forming means, the processing means
• for determining whether the at least one color cartridge means contains insufficient color toner for printing an image according to a first image job;
• and
• for queuing a second image job, the second image job not requiring the at least one color cartridge means, before the first image job requiting the at least one color cartridge means if the at least one color cartridge means contains insufficient color toner for printing the image of the first image job;
• and
• means for controlling the image forming means for forming images in accordance with the queue.