Toner replenishment device for an image forming apparatus which employs pixel density and toner density information

An image forming apparatus comprising:

• image forming means for forming a latent image on a photosensitive member in accordance with an image signal expressing a density level for each pixel;
• a developing device which stores developer including toner and develops the latent image on said photosensitive member with toner;
• predicting means for predicting the amount of toner consumed in development based on the density level of each pixel expressed by image signals;
• detecting means for detecting an environmental condition within the image forming apparatus;
• and
• toner replenishment control means for correcting the toner consumption predicted by said predicting means based on the environmental condition detected by said detecting means to obtain an amount of toner replenishment which maintains constant toner concentration in said developing device.

An image forming apparatus comprising:

• image forming means for forming a latent image on a photosensitive member in accordance with image signal expressing a density level for each pixel;
• a developing device which stores developer including toner and develops the latent image on said photosensitive member with toner;
• predicting means for predicting the amount of toner consumed in development based on the density level of each pixel expressed by image signals;
• detecting means for detecting the effectiveness of toner image transfer from the photosensitive member to a sheet;
• toner replenishment control means for correcting the toner consumption predicted by said predicting means based on the effectiveness detected by said detecting means, so as to determine the amount of toner to be replenished.

An image forming apparatus comprising:

• image forming means for forming a latent image on a photosensitive member in accordance with an image signal expressing a density level for each pixel;
• a developing device which stores developer including toner and develops the latent image on said photosensitive member with toner;
• estimating means for estimating toner concentration in a developer within the developer device after a predetermined number of images have been formed on said photosensitive member;
• determining means for determining a difference between said estimated toner concentration and a standard toner concentration;
• predicting means for predicting an amount of toner consumed in development based on the density level of each pixel expressed by image signals;
• and
• toner replenishment control means for distributing said determined difference over a plurality of image forming operations and adjusting said amount of consumed toner predicted by predicting means by said distributed difference for each of said plurality of image forming operations.