An image forming apparatus includes a photosensitive member, a charging member, a developing member, a first contacting member contacting to the developing member, and first to third power sources. The first power source generates a first voltage lower and supply to the charging member. The second power source generates a second voltage lower than the first voltage from the first voltage and applies to the first contacting member. The third power source generates a third voltage lower than the second voltage from the second voltage and applies to the developing member.

A developing cartridge includes a casing having an outer surface, a developing roller, a first electrode, and a boss. The developing roller is movable together with the casing and includes a developing roller shaft extending along a first axis extending in a first direction. The developing roller is rotatable about the first axis. The first electrode is positioned at one end portion in the first direction of the developing roller shaft, and electrically connected to the developing roller shaft. The boss is positioned at one end portion in the first direction of the outer surface. The boss extends in the first direction and is engageable with the drum unit. A part of the first electrode is configured to contact with a second electrode of the drum unit as a result of pivotal movement of the developing cartridge about the boss relative to the drum unit.

An electrostatic printer comprises a charging unit, a photoconductor member, an imaging unit, a developer unit and a controller. The charging unit is to charge the photoconductor member to a charged voltage. The imaging unit is to generate a latent electrostatic image on the photoconductor member by discharging areas of the charged photoconductor member. The developer unit is to develop a toner image on the photoconductor member using a developer voltage. The controller is to change the developer voltage, and to change the charged voltage dependent on the change of the developer voltage.

An example method of controlling a printing process in accordance with aspects of the present disclosure includes controlling an optical density of a printed image such that the optical density is increased for a predetermined portion of a leading edge of a page.

In a cartridge, a housing has a developer accommodating portion and includes a first side wall and a second side wall. A coupling member is disposed at a position opposite to the developer accommodating portion with respect to the first side wall. A detection body is disposed at a position opposite to the developer accommodating portion with respect to the second side wall. A first driving force transmission member is positioned at the same side with the coupling member with respect to the first side wall, and transmits driving force from the coupling member to a rotating member. A second driving force transmission member is positioned at the same side with the detection body with respect to the second side wall, and transmits driving force from the rotating member to the detection body.

The image forming apparatus of the present embodiment has two limiters composed of a conventional high order limiter and a low order limiter, and carries out control to switch the limiter according to a temperature and a humidity so as not to reach a image contrast potential equal to or greater than those limiters. Carrier development can occur if image formation is performed in a state where the image contrast potential is high. Therefore, by providing a low order limiter as in the present embodiment and carrying out control so as not to exceed the low order limiter at the time of the image formation, an occurrence of the carrier development can be suppressed, and an image density can also be within a prescribed range.

A relationship 150≦Rs (Ω)/Rm (Ω)≦4000 is established in an environment of a temperature of 15° C. and a humidity of 10% in a case where a surface resistance of a transfer roller is Rs (Ω) when a current is fed between a pair of electrodes facing each other in an axial direction of the transfer roller and arranged on a surface of the transfer roller with an interval of 5 mm therebetween, the electrodes having a width of 20 mm in a circumferential direction of the transfer roller in a state of being arranged on the transfer roller, and in a case where a combined resistance of a first layer and a second layer is Rm (Ω) when the current is fed from a core portion to an outer peripheral surface of the second layer.

An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm.sup.2 or more and 3.5 gf/mm.sup.2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

An image forming apparatus includes a photosensitive member, a charging member, an exposing device, a developing device, a transfer member, a brush, a voltage applying portion, and a control portion controlling a surface potential of the photosensitive member at the brush contacting position. When a value of subtracting a value of the surface potential of the photosensitive member in the brush contacting position from a value of the brush voltage is defined as a contacting position potential difference, the control portion controls the surface potential of the photosensitive member in the brush contacting position so that the contacting position potential difference is changed from a first potential difference to a second potential difference in a predetermined direction which is either one of an increasing direction or a decreasing direction, and then the contacting position potential difference is changed from the second potential difference to a third potential difference in the predetermined direction.

An image forming apparatus includes a drive device including a first drive transmission passage through which a driving force of a drive source is transmitted to a developer bearer via a first joint and a second drive transmission passage through which the driving force is transmitted to a rotary body via a second joint. The first drive transmission passage and the second drive transmission passage are defined such that one of a first drive transmission ratio to the first joint of the first drive transmission passage and a second drive transmission ratio to the second joint of the second drive transmission passage is an integral multiple of the other of the first drive transmission ratio from the drive source to the first joint of the first drive transmission passage and the second drive transmission ratio from the drive source to the second joint of the second drive transmission passage.