An image forming apparatus includes an image carrier, a developing device, a voltage applier, a current detector, a cleaning blade, and a control device. The control device acts as a measurer and an estimator. The measurer changes the DC bias to a first value and a second value, and acquires a first magnitude of the developing current corresponding to the first value, and a second magnitude of the developing current corresponding to the second value, from the current detector. The estimator calculates a current ratio between the first magnitude and the second magnitude, and estimates deterioration status of the cleaning blade, according to the value of the current ratio.

In one example of the disclosure, a first voltage is provided to an electrode of a development assembly during a first printing operation. The developer assembly includes a current-resistant coating and is to develop print fluid with conductive particles. Contemporaneous with the providing of the first voltage to the electrode, a second voltage is provided to a squeegee roller of the developer assembly. Data indicative of a measurement of optical density of a first image printed utilizing the developer assembly is received. During a second printing operation, if the measured optical density is outside a target optical density, contemporaneously the first voltage is provided to the electrode and a third voltage to the squeegee roller to adjust image optical density.

In one example of the disclosure, a first voltage is provided to an electrode of a development assembly during a first printing operation. The developer assembly includes a current-resistant coating and is to develop print fluid with conductive particles. Contemporaneous with the providing of the first voltage to the electrode, a second voltage is provided to a squeegee roller of the developer assembly. Data indicative of a measurement of optical density of a first image printed utilizing the developer assembly is received. During a second printing operation, if the measured optical density is outside a target optical density, contemporaneously the first voltage is provided to the electrode and a third voltage to the squeegee roller to adjust image optical density.

A device for removing toner attached to a transfer roller in an image forming apparatus is disclosed. The device includes a bar brush to contact an outer circumferential surface of the transfer roller, where the bar brush extends along a part of a longitudinal length of the transfer roller. The device includes an elongated cleaning member to contact the outer circumferential surface of the transfer roller, where the elongated cleaning member extends along the longitudinal length, entirely, of the transfer roller.

An image forming apparatus includes a black image carrier that holds toner images of black, a yellow image carrier that holds toner images of yellow, a magenta image carrier that holds toner images of magenta, a cyan image carrier that holds toner images of cyan, at least one spot-color image carrier, and multiple collecting units. The at least one spot-color image carrier holds toner images of a spot color other than black, yellow, magenta, and cyan. Each of the collecting units collects waste toner. The collecting units include a first collecting unit that collects waste toner removed from the black image carrier, and waste toner removed from the spot-color image carrier.

An image forming apparatus includes a black image carrier that holds toner images of black, a yellow image carrier that holds toner images of yellow, a magenta image carrier that holds toner images of magenta, a cyan image carrier that holds toner images of cyan, at least one spot-color image carrier, and multiple collecting units. The at least one spot-color image carrier holds toner images of a spot color other than black, yellow, magenta, and cyan. Each of the collecting units collects waste toner. The collecting units include a first collecting unit that collects waste toner removed from the black image carrier, and waste toner removed from the spot-color image carrier.

An image forming apparatus includes an image forming unit, a first rotary member, a second rotary member, a web, a feed roller, a winding roller, a contact member, a detection unit, and a control unit. In a state where the apparatus is turned from a first power-ON state to a second power-ON state through a power-OFF state after the contact member reached a notch, if a difference between a diameter of a web at an end of the first power-ON state and the diameter of the web at a start of the second power-ON state is equal to or greater than a predetermined value, the control unit controls the image forming unit not to form a toner image. In the state after the contact member reached the notch, if the difference is smaller than the predetermined value, the control unit permits the image forming unit to form a toner image.

An image forming apparatus includes an image forming unit, a first rotary member, a second rotary member, a web, a feed roller, a winding roller, a contact member, a detection unit, and a control unit. In a state where the apparatus is turned from a first power-ON state to a second power-ON state through a power-OFF state after the contact member reached a notch, if a difference between a diameter of a web at an end of the first power-ON state and the diameter of the web at a start of the second power-ON state is equal to or greater than a predetermined value, the control unit controls the image forming unit not to form a toner image. In the state after the contact member reached the notch, if the difference is smaller than the predetermined value, the control unit permits the image forming unit to form a toner image.

A developing device includes a case, a developer holder, a suction duct and a carrier catcher. The case accommodates a developer containing a toner and a carrier. The developer holder is disposed so as to face an image holder disposed outside the case and supplies the developer to the image holder. The suction duct sucks and collects a scattered toner floating in a space around the developer holder. The carrier catcher is formed in a vertical direction and disposed on a lower surface of a path of the suction duct.

A developing device includes a case, a developer holder, a suction duct and a carrier catcher. The case accommodates a developer containing a toner and a carrier. The developer holder is disposed so as to face an image holder disposed outside the case and supplies the developer to the image holder. The suction duct sucks and collects a scattered toner floating in a space around the developer holder. The carrier catcher is formed in a vertical direction and disposed on a lower surface of a path of the suction duct.