When this patch is not installed even if the job is in black & white the 1st BTR's of the color stations CMY in the IOT are not retracted in B & W mode and the machine will keep the process control as it is in a full color job. This leads to low toner in the developer tanks later when the customer is printing full color jobs afterwards. When this patch is installed, if grayscale or Black & White jobs are sent the color stations CMY in the IOT are not retracted, it prints in k-only mode. The switch to the k-only mode or Color mode is automatic depending on the job sent.