Abstract: A stationary magnet is disposed in a developing sleeve for carrying a one component magnetic developer. A regulating sleeve for regulating a layer of the developer is disposed opposed to the developing sleeve. The regulating sleeve rotates in the same direction as the developing sleeve. In the regulating sleeve, there is disposed a magnet or magnetic member cooperative with the stationary magnet to form a magnetic field in a gap between the developing sleeve and the regulating sleeve.

Abstract: A toner for electrophotography, comprising toner particles and an additive, is obtained by mixing toners A and B together which are obtained by respectively adding the additive to each of at least two toner particle groups (a) and (b) having different particle size distributions. The average particle size of the toner particle group (a) is smaller than that of the toner particle group (b), and the amount of additive in the toner A is larger than that in the toner B. The toner reduces the differences in development conditions between different particle sizes due to broadening of toner particle size distribution, thereby enabling a stable image quality to be obtained which maintains a high image density for an extended period of time and is relatively free from fog generation in non-image portions.

Abstract: An image forming method is disclosed which comprises forming a latent image on a latent image bearing member, carrying a magnetic toner onto a developer carrying member provided with a magnetic field forming means, forming on the developer carrying member a layer of the magnetic toner, and developing the latent image while transferring the magnetic toner to the latent image bearing member. The magnetic toner contains a magnetic material having an intensity of magnetization of from 10 emu/g to 40 emu/g in a magnetic field of 1K oersted and formed of a metal oxide having a horizontal direction Feret's diameter of from 0.05 .mu.m to 0.5 .mu.m, and chainlike masses of the magnetic toner, formed on the developer carrying member, are in a density of not less than 8.times.10.sup.4 ears/cm.sup.2 in a developing zone formed between the latent image bearing member and developer carrying member. The chainlike masses each have a length of not more than 180 .mu.

Abstract: An image-forming apparatus for developing an electrostatic latent image using a two-component developer. Toner replenishment is effected in different modes when the toner concentration is in a lower toner concentration range than a desired toner concentration and when it is lower than that toner concentration range.

Abstract: An image forming apparatus includes an image bearing member; a latent image forming device for forming a latent image on the image bearing member; a developing device for developing the latent image, including, a developer container for containing a developer including carrier and toner particles, a toner container for containing the toner particles, a toner supply device for supplying the toner particles from the toner container to the developer container, a developer carrying member for carrying on its surface the developer supplied from the developer container, a sensor for detecting a toner content in the developer; a control device for controlling the toner supply from the toner container to the developer container on the basis of an output of the sensor, wherein when a toner supply signal is not produced within a predetermined period of time, a predetermined latent image is formed on the image bearing member, and the predetermined latent image is developed by the developing device.

Abstract: An image forming apparatus using two component developer. When a toner content in the developer becomes out of a predetermined range as a result of the consumption of the toner, a control device effects a toner replenishing operation, and simultaneously, the image forming operation is substantially delayed.