Developer collecting device and image forming apparatus

An image forming apparatus comprising:

• an image carrying member on which a toner image is formed by developing an electrostatic latent image that is formed on the image carrying member in accordance with image information;
• a developing unit that accommodates developer including toner and a carrier, the developing unit discharging a portion of the developer while the developing unit circulates the accommodated developer, being supplied with new developer, and developing the electrostatic latent image on the image carrying member using the toner in the developer, wherein the developing unit includes a developer transporting member that, while rotating, carries on a surface thereof the developer that is accommodated in the developing unit and transports the developer to a location opposing the image carrying member;
• a transfer unit that transfers the toner image on the image carrying member to a sheet;
• a fixing unit that fixes the toner image transferred to the sheet to the sheet;
• and
• a developer collecting device that collects the developer discharged from the developing unit,
• wherein the developing collecting device includes
• a collecting box that accommodates the developer discharged from the developing unit so that the developer accommodated in the collecting box does not return to the developing unit,
• a guide cylinder that connects the developing unit and the collecting box to each other, the guide cylinder guiding movement of the developer discharged from the developing unit to the collecting box,
• a transporting member that is disposed in the guide cylinder, that extends in a developer transport direction, and that transports the developer towards the collecting box by rotation of the transporting member, and
• a rotation controller that controls rotation speed of the transporting member in accordance with conditions that affect a capability of developing the electrostatic latent image on the image carrying member, wherein the rotation controller performs control that reduces the rotation speed of the transporting member in accordance with an increase in rotation speed of the developer transporting member.

A developer collecting device comprising:

• a collecting box that accommodates developer discharged from a developing unit, the developing unit accommodating developer including toner and a carrier, the developing unit developing an electrostatic latent image on a development member using the toner in the developer;
• a guide cylinder that connects the developing unit and the collecting box to each other, the guide cylinder guiding movement of the developer discharged from the developing unit to the collecting box;
• a transporting member that is disposed in the guide cylinder, that extends in a developer transport direction, and that transports the developer towards the collecting box by rotation of the transporting member;
• a rotation controller that controls rotation speed of the transporting member in accordance with conditions that affect a capability of developing the electrostatic latent image on the development member;
• and
• a sensor that measures a concentration of the toner with respect to the carrier in the developer that is accommodated in the developing unit,
• wherein the rotation controller performs control that reduces the rotation speed of the transporting member in accordance with an increase in the concentration of the toner.

A developer collecting device comprising:

• a collecting box that accommodates developer discharged from a developing unit, the developing unit accommodating developer including toner and a carrier, the developing unit developing an electrostatic latent image on a development member using the toner in the developer;
• a guide cylinder that connects the developing unit and the collecting box to each other, the guide cylinder guiding movement of the developer discharged from the developing unit to the collecting box;
• a transporting member that is disposed in the guide cylinder, that extends in a developer transport direction, and that transports the developer towards the collecting box by rotation of the transporting member;
• a rotation controller that controls rotation speed of the transporting member in accordance with conditions that affect a capability of developing the electrostatic latent image on the development member;
• a measuring unit that measures the number of pixels in which the toner adheres to the electrostatic latent image on the development member when developing the electrostatic latent image using the developing unit;
• and
• a calculating unit that calculates an accumulated time of use of the developing unit,
• wherein the rotation controller performs control that increases the rotation speed of the transporting member in accordance with (i) an increase in the number of pixels in which the toner adheres to the electrostatic latent image and (ii) an increase in the accumulated time of use.