US 9,811,022 B2
Image forming apparatus having development contrast control
Noriyuki Okada, Matsudo (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Feb. 29, 2016, as Appl. No. 15/56,050.
Application 15/056,050 is a continuation of application No. PCT/JP2017/073846, filed on Sep. 3, 2014.
Claims priority of application No. 2013-182008 (JP), filed on Sep. 3, 2013.
Prior Publication US 2016/0195832 A1, Jul. 7, 2016
Int. Cl. G03G 15/08 (2006.01); G03G 15/06 (2006.01); G03G 15/09 (2006.01)
CPC G03G 15/065 (2013.01) [G03G 15/0849 (2013.01); G03G 15/09 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
an image bearing member configured to carry an image;
a developing device configured to develop a latent image formed on said image bearing member with a developer including toner and carrier;
a toner content sensor configured to detect a ratio of the toner to the developer in said developing device;
a toner container configured to contain the toner to be supplied to said developing device;
an executing portion configured to execute an operation in a first toner supplying mode for supplying the toner from said toner container into said developing device when the ratio indicated by an output of said toner content sensor is in a predetermined range and to execute an operation in a second toner supplying mode for interrupting an image forming operation and for supplying the toner from said toner container into said developing device when the ratio indicated by the output of said toner content sensor is lower than the predetermined range;
a notifying portion configured to notify necessity for exchange of said toner container when the ratio indicated by the output of said toner content sensor reaches a set level lower than the predetermined range; and
a controller configured to control an image forming condition so as to change, on the basis of the output of said toner content sensor, a development contrast which is a potential difference between an image portion potential of a maximum image density in the latent image and a development DC bias potential applied to said developing device,
wherein said controller sets the development contrast at a level higher than that when the ratio is in the predetermined range, at least in part of a period from when the ratio indicated by the output of said toner content sensor becomes lower than the predetermined range to when the ratio indicated by the output of said toner content sensor reaches the set level.