Image forming apparatus operable in writing position correction mode

摘要

Precise correction of a position of a toner image formed by an image forming station can be accomplished in a device using two-component developer. An electrostatic latent image for forming a color misregistration correction pattern for color misregistration correcting includes a first latent image pattern and a second latent image pattern at a position downstream of the first latent image pattern with respect to the moving direction of the electrostatic latent image. The toner image resulting from the development of the first latent image pattern has a width, measured in the image moving direction, which is greater than that of the toner image resulting from the development of a latent image pattern alone, which is the same as the first latent image pattern, or the toner image resulting from the development of the first latent image pattern has an image density at a downstream end portion with respect to the moving direction, which density is higher than that of the toner image resulting from the development of the latent image pattern alone, which is the same as the first latent image pattern.

主权项

1. An image forming apparatus comprising:
a first image forming station configured to form a toner image and a second image forming station configured to form a toner image, each of the first image forming station and the second image forming station including a rotatable image bearing member, a latent image forming device configured to form an electrostatic latent image on the image bearing member, and a developing device configured to develop the electrostatic latent image formed on the image bearing member, the developing device including a developer carrying member configured to carry a developer comprising toner and a magnetic carrier and movable in the same direction at a position where the developer carrying member is opposed to the image bearing member; a toner sensor configured to detect a toner image for registration correction of images formed by the first image forming station and the second image forming station; and a controller capable of executing an operation in a position correction mode for correcting a writing position of the images formed by the first image forming station and the second image forming station on the basis of a result of detection of the toner images for the registration correction by the toner sensor, wherein in the operation in the position correction mode, the controller controls each of the first image forming station and the second image forming station such that in each of the first image forming station and the second image forming station, a first latent image pattern which is a latent image for the toner image for the registration correction and a second latent image pattern are formed such that, in the first image forming station, the first latent image pattern and the second latent image pattern are formed on the same image bearing member of the first image forming station, in the second image forming station, the first latent image pattern and the second latent image pattern are formed on the same image bearing member of the second image forming station, in each of the first image forming station and the second image forming station, the second latent image pattern is formed at an upstream side of the first latent image pattern with respect to a moving direction of the image and is not formed at a downstream side of the first latent image pattern, and in each of the first image forming station and the second image forming station, the second latent image pattern is continuous with the first latent image pattern, and an image density of the toner image provided by developing the second latent image pattern is lower than an image density of the toner image provided by developing the first latent image pattern.