Image forming apparatus

1. An image forming apparatus comprising:

a subjected-to-development member that rotates and has a surface on which an electrostatic latent image is formed and developed with a developer;

a first developer-transporting unit disposed so as to face the subjected-to-development member, the first developer-transporting unit carrying the developer on a circumferential surface thereof and transporting the developer toward the subjected-to-development member while rotating in a first direction in which an opposing area of the first developer-transporting unit that faces a first opposing portion of the subjected-to-development member moves in the same direction as the first opposing portion of the subjected-to-development member;

a regulator that regulates the thickness of a layer of the developer carried by the circumferential surface of the first developer-transporting unit, the regulator being disposed upstream from the opposing area of the first developer-transporting unit in the first direction at a distance from the circumferential surface of the first developer-transporting unit;

a second developer-transporting unit disposed upstream from the first developer-transporting unit in a direction of rotation of the subjected-to-development member so as to face the subjected-to-development member and downstream from the regulator in the first direction so as to face the first developer-transporting unit, the second developer-transporting unit carrying the developer on a circumferential surface thereof and transporting the developer toward the subjected-to-development member while rotating in a second direction in which an opposing area of the second developer-transporting unit that faces a second opposing portion of the subjected-to-development member moves in a direction opposite to the second opposing portion of the subjected-to-development member;

a density detecting unit that detects center density and edge density of a developed image formed on the subjected-to-development member by the first developer-transporting unit and the second developer-transporting unit, the center density being a density of the developed image at or around a center position of the subjected-to-development member in a width direction of the subjected-to-development member that intersects a direction of movement of the surface of the subjected-to-development member, the edge density being a density of the developed image at an edge position of the subjected-to-development member in the width direction of the subjected-to-development member;

a reference-image forming controller that forms a reference developed image on the subjected-to-development member by forming an electrostatic latent image having a uniform image density at the center position and the edge position in the width direction and by causing the first developer-transporting unit and the second developer-transporting unit to develop the electrostatic latent image; and

a speed controller that increases rotation speed of the second developer-transporting unit as compared to the case of forming the reference developed image if the center density of the reference developed image detected by the density detecting unit is lower than the edge density.

2. The image forming apparatus according to claim 1 , wherein the speed controller increases rotation speed of the first developer-transporting unit in conjunction with an increase in rotation speed of the second developer-transporting unit.