Developing unit and image forming apparatus

• US 20070104499A1
• Filed: 08/24/2006
• Published: 05/10/2007
• Est. Priority Date: 11/10/2005
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Fujimori, Kohta, Ariizumi, Osamu, Morimoto, Ryohta, Uchida, Fukutoshi, Kobayashi, Shinji, Ishibashi, Hitoshi, Hasegawa, Shin, Enami, Takashi, Takeuchi, Nobutaka, Tanaka, Kayoko, Hirayama, Yushi, Kobayashi, Kazumi, Kato, Shinji, Watanabe, Naoto
• Granted Patent: US 7,672,602 B2
• Time in Patent Office: Days
• US Class Current: 399/27
• CPC Class Codes: G03G 15/0849 Detection or control means for the developer concentration
• CPC Class Codes: G03G 15/0856 Detection or control means for the developer level
• CPC Class Codes: G03G 15/5062 by measuring the characteristics of an image on the copy material
• CPC Class Codes: G03G 15/556 for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement
• CPC Class Codes: G03G 2215/00755 of sheet toner density

Abstract

A developing unit supplies toner from a developing roller to an electrostatic latent image formed on an image carrier, and creates a visual image. A forced consumption unit causes, when a proportion of number of pixels used for forming the electrostatic latent image for a maximum image effective-width is equal to or less than a predetermined value, a forced consumption of toner by an amount corresponding to a difference between a toner amount corresponding to the number of pixels and a predetermined toner consumption amount. The forced consumption unit adds toner of an amount used in the forced consumption to an amount of toner to be supplied in a next imaging process.

Claims

1. A developing unit that supplies toner from a developing roller to an electrostatic latent image formed on an image carrier, and creates a visual image, the developing unit comprising:

a forced consumption unit that causes, when a proportion of number of pixels used for forming the electrostatic latent image for a maximum image effective-width is equal to or less than a predetermined value, a forced consumption of toner by an amount corresponding to a difference between a toner amount corresponding to the number of pixels and a predetermined toner consumption amount, wherein

the forced consumption unit adds toner of an amount used in the forced consumption to an amount of toner to be supplied in a next imaging process.

2. The developing unit according to claim 1, wherein

the forced consumption unit causes, when an average value of the number of pixels of a plurality of copies is equal to or less than a predetermined toner consumption amount, a forced consumption of toner by an amount corresponding to a difference between a toner amount corresponding to the average value of the number of pixels and a predetermined toner consumption amount.

3. The developing unit according to claim 2, wherein

the forced consumption unit causes the forced consumption of the toner by forming a latent image of a halftone dot-shaped pattern on a non-image portion on the image carrier and visualizing the latent image.

4. An image forming apparatus comprising:

a developing unit that supplies toner from a developing roller to an electrostatic latent image formed on an image carrier, and creates a visual image, wherein

the developing unit includes a forced consumption unit that causes, when a proportion of number of pixels used for forming the electrostatic latent image for a maximum image effective-width is equal to or less than a predetermined value, a forced consumption of toner by an amount corresponding to a difference between a toner amount corresponding to the number of pixels and a predetermined toner consumption amount, and

the forced consumption unit adds toner of an amount used in the forced consumption to an amount of toner to be supplied in a next imaging process.