Developing agent density control method of varying development bias in density control

• US 5,469,244 A
• Filed: 03/14/1994
• Issued: 11/21/1995
• Est. Priority Date: 03/19/1993
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Menjo, Takeshi, Ogata, Takao
• Primary Examiner(s): Royer, William J.
• Application Number:
  US08/209,256
• Time in Patent Office: 617 Days
• Field of Search: 355/203, 355/208, 355/214, 355/246, 118/689-691
• US Class Current: 399/30
• CPC Class Codes: G03G 15/0855 the concentration being measured by optical means
• CPC Class Codes: G03G 15/5041 Detecting a toner image, e.g. density, toner coverage, using a test patch G03G15/553 takes precedence
• CPC Class Codes: G03G 2215/00042 Optical detection

Abstract

A developing agent density control method includes the steps of forming a density control latent image with a predetermined potential on an image carrier, developing the density control latent image by applying a density control development bias and using a two-component developing agent having a toner and a carrier, sensing the density of the density control image, and controlling a toner-to-carrier ratio on the basis of the sensed density. In this method, the density control development bias is different from a print development bias.

Claims

1. A developing agent density control method comprising the steps of:

forming a density control latent image with a predetermined potential on an image carrier;

developing the density control latent image by applying a density control development bias and using a two-component developing agent having a toner and a carrier;

sensing a density of the density control image; and

controlling a toner-to-carrier ratio on the basis of the sensed density,

wherein the density control development bias causes a larger variation in output image density with respect to a variation in the toner-to-carrier ratio than that caused by a print development bias.

2. A method according to claim 1, wherein the toner is a black toner containing carbon.

3. A method according to claim 1, wherein the density control latent image is a patch image.

4. A developing agent density control method comprising the steps of:

forming a density control latent image with a predetermined potential on an image carrier;

developing the density control latent image by applying a density control development bias and using a two-component developing agent having a toner and a carrier;

sensing a density of the density control image; and

controlling a toner-to-carrier ratio on the basis of the sensed density,

wherein a frequency of the density control development bias is higher than that of a print development bias.

5. A method according to claim 4, wherein the toner is a black toner containing carbon.

6. A method according to claim 4, wherein the density control latent image is a patch image.