Abstract: An image forming apparatus according to an embodiment includes an image bearing body, a developing roller, a housing, and a gap adjusting member. The image bearing body includes a first rotating shaft and includes a first surface on which a latent image is formed. The developing roller includes a second rotating shaft, includes a second surface, includes a bearing, and supplies a developer to the latent image and develops the latent image. The housing rotatably supports the second rotating shaft. The gap adjusting member includes a shaft hole for rotatably receiving one end of the first rotating shaft and includes a cam surface. The gap adjusting member is turned around the first rotating shaft and is fixed to the housing in a turning position where a gap is uniform in a direction of the second rotating shaft of the developing roller.

Abstract: Examples described herein relate to a system consistent with the disclosure. For instance, the system may comprise a printing device including hardware to adjust a velocity of a development unit within the printing device, a memory resource, and a controller in communication with the memory resource to determine an average usage condition of the printing device, wherein the average usage condition is based on at least one of a print coverage and a quantity of pages printed by the printing device, and adjust a velocity of the development unit based on the average usage condition.

Abstract: A controller is configured to execute a larger gamut technology mode in which the controller performs image formation by controlling a ratio of a rotation speed of a development roller to a rotation speed of a photosensitive drum such that the ratio becomes a second speed ratio higher than a first speed ratio in a normal mode. The controller is configured to, when the controller executes the larger gamut technology mode, control transfer voltage based on a humidity around an image forming apparatus.

Abstract: A developing device includes a developer carrier configured to carry a developer to be supplied to an image carrier on which an electrostatic latent image is to be formed, a conveying unit configured to convey the developer containing a toner and a carrier, a regulating member configured to regulate the developer carried by the developer carrier to a specified amount, a developer accumulating member disposed upstream of the regulating member in a rotation direction of the developer carrier, the developer accumulating member forming an accumulating portion in which the developer accumulates, and a rotation member disposed between the developer accumulating member and the developer carrier, the rotation member being rotated to allow the developer to pass through a space between the developer accumulating member and the rotation member.

Abstract: An image forming apparatus is capable of performing a second image forming operation in which a peripheral velocity ratio of a developer bearing member to an image bearing member becomes greater than that in a first image forming operation, and in which a potential difference between a developing bias applied to the developer bearing member and a supply bias applied to a supply member becomes a potential difference at which a urging force causing a developer at the contact portion between the developer bearing member and the supply member to move from the supply member to the developer bearing member becomes smaller than that in the first image forming operation, or becomes a potential difference at which a urging force causing the developer to move from the developer bearing member to the supply member is generated.

Abstract: Provided is an image forming apparatus including an image carrier on which a latent image is developed, a developing roller that is provided to face the image carrier to perform development for the latent image of the image carrier, an urging unit that urges the image carrier and the developing roller so that the image carrier and the developing roller approach each other, and a distance regulating unit that includes a viscoelastic body that is deformed according to a change of a distance between the image carrier and the developing roller, and regulates at least one of a maximum value of the distance between the image carrier and the developing roller and a minimum value of the distance between the image carrier and the developing roller so that the distance between the image carrier and the developing roller falls within a predetermined range.

Abstract: An image forming apparatus of the present invention includes a developing device. In a case body of the developing device, a first storage chamber and a second storage chamber are formed. A first agitating screw is provided in the first storage chamber and a second agitating screw is provided in the second storage chamber. A developing roller is provided in the second storage chamber. A control portion controls driving of a first motor and a second motor. When toner installation is performed, the control portion controls driving of the first motor at a rotational speed higher than a rotational speed for development operation in a state where the second motor is stopped. When a certain condition is satisfied, the control portion starts control of driving of the second motor, to drive rotation of the second motor.

Abstract: A developing device includes a developer bearer and a regulation member. The developer bearer bears developer on a surface thereof. The developer bearer is rotatable forward and in reverse. The regulation member is disposed in contact or non-contact with the surface of the developer bearer to regulate amount of the developer on the developer bearer. In a non-development period, when the developer bearer rotates in a direction of reverse rotation opposite to a direction of forward rotation in which the developer bearer rotates in a development period, the developer bearer stops a series of rotating operations after the developer bearer rotates in the direction of forward rotation as a last rotating operation. A total rotation amount of forward rotation is set to be greater than a total rotation amount of reverse rotation in the series of rotating operations.

Abstract: Provided is a color image forming apparatus that includes: image carriers that form toner image of black and other colors; an intermediate transfer body that makes contact with the image carriers; and transfer units that transfer the toner images on the image carriers to the intermediate transfer body. A line velocity difference is set between the image carriers and the intermediate transfer body. An accelerated cohesion degree of toner is equal to or larger than 54%. A linear velocity difference X1 between the image carrier for black and the intermediate transfer body satisfies a relation of 0<X1?1.2 mm/sec. A linear velocity difference X2 between the image carriers for the colors and the intermediate transfer body satisfies a relation of 2.1?X2?4.0 mm/sec.

Abstract: In an image forming apparatus, a control circuit rotationally drives a development roller at a predetermined rotation speed during a development process, in which the development roller has depression portions and land portions on a circumferential surface. The depression portions and the land portions are oblique grooves in the surface. While the development roller is rotationally driven, the control circuit controls the predetermined rotation speed such that a crossing angle approximates 90°. The crossing angle is formed by a screen line in the electrostatic latent image on the circumferential surface of the latent image support and an area where the land portion of the development roller substantially passes over the circumferential surface of the latent image support.

Abstract: An image forming apparatus includes: an image bearing member; a development device; a speed varying unit that can vary a speed of a developer bearing member; a sensing portion that senses an environmental temperature around the development device; and a controller that can perform a mode in which, compared with a period which an image forming region of the image bearing member passes through the developing region, the rotation speed of the developer bearing member slows down a period which a non-image forming region of the image bearing member passes through the developing region, wherein based on sensing result of the sensing portion, the controller performs the mode when the environmental temperature is higher than a predetermined value, and the controller does not perform the mode when the environmental temperature is lower than the predetermined value.

Abstract: An image forming apparatus is provided, which includes a controller configured to determine a moment for switching a circumferential velocity of a development roller to a first circumferential velocity from a second circumferential velocity lower than the first circumferential velocity based on a moment when the controller issues to a sheet feeding unit an instruction to start feeding of a sheet, and to determine a moment for switching the circumferential velocity of the development roller to the second circumferential velocity from the first circumferential velocity based on a moment when a first detector detects existence of the sheet ejected from a registration roller.

Abstract: An image forming apparatus includes: an image bearing member; an electrostatic image forming device; and a developer carrying member. The developer carrying member is provided so as to be rotated in a direction opposite to a rotational direction of the image bearing member at a peripheral speed higher than that of the image bearing member. When the peripheral speed of the image bearing member is Vp (m/sec), the peripheral speed of the developer carrying member is Vs (m/sec), and a time, of movement of the developer from the surface of the developer carrying member to the image bearing member, actually measured in a gap between the image bearing member and the developer carrying member is Tsd (sec), the peripheral speeds Vp and Vs and the time Tsd satisfy the following relationship: (Vs?Vp)×Tsd<3×105 (m).

Abstract: When at least one of first image data and second image data is captured, according to a moving speed of an object while an image sensor is capturing an image, exposure time for capturing the image is controlled to decrease a difference between object blur widths in a direction in which the object moves.

Abstract: In an image forming apparatus, a control circuit rotationally drives a development roller at a predetermined rotation speed during a development process, in which the development roller has depression portions and land portions on a circumferential surface. The depression portions and the land portions are oblique grooves in the surface. While the development roller is rotationally driven, the control circuit controls the predetermined rotation speed such that a crossing angle approximates 90°. The crossing angle is formed by a screen line in the electrostatic latent image on the circumferential surface of the latent image support and an area where the land portion of the development roller substantially passes over the circumferential surface of the latent image support.

Abstract: Provided is an image forming apparatus including: photosensitive drums; electrostatic latent image forming units; developing sleeves; patch detection sensors which detect image densities of the toner images formed by the electrostatic latent image forming units; and toner replenishment units which replenish the developing sleeves with the toner based on the detection results of the patch detection sensors. Further, controllers are provided to make a control such that the rotation speeds of the developing sleeves at the time of forming the reference toner image is higher than the rotation speeds of the developing sleeves at the time of forming a normal image.

Abstract: An image forming apparatus includes a developer bearing body for supplying developer to a surface of the image bearing body, on which an electrostatic latent image is formed by a latent image forming unit; a driving unit for rotating the developer bearing body; a speed control unit for determining a rotation speed of the developer bearing body; a drive control unit for controlling the driving unit so that the developer bearing body rotates at the determined rotation speed; and a control unit for determining the amount of developer to be disposed of on the basis of the determined rotation speed and controlling disposal of the determined amount of developer on the surface of the developer bearing body.

Abstract: A printer according to the present invention is a so-called tandem-type printer, and has a configuration that a motor gear is directly connected to an M-photoconductor driving gear and an idler gear is directly connected to a Y-photoconductor driving gear and the M-photoconductor driving gear. A diameter of the Y and M photoconductors driving gear, a distance between transfer sections of the Y and M photoconductors, a motor gear input angle, and an idler input angle are set so that an absolute value of a value obtained by subtracting 1 from an ideal amplitude ratio, which indicates a ratio of an ideal amplitude of an eccentric component of the Y-photoconductor driving gear to an actual amplitude of an eccentric component of the M-photoconductor driving gear, is equal to or less than a maximum allowable amplitude ratio.

Abstract: An image forming apparatus is provided, which includes a controller configured to determine a moment for switching a circumferential velocity of a development roller to a first circumferential velocity from a second circumferential velocity lower than the first circumferential velocity based on a moment when the controller issues to a sheet feeding unit an instruction to start feeding of a sheet, and to determine a moment for switching the circumferential velocity of the development roller to the second circumferential velocity from the first circumferential velocity based on a moment when a first detector detects existence of the sheet ejected from a registration roller.

Abstract: An image forming apparatus is provided, which includes a controller configured to switch a circumferential velocity of a development roller from a second circumferential velocity to a first circumferential velocity no later than when development of a photoconductive drum is started and to switch the circumferential velocity of the development roller from the first circumferential velocity to the second circumferential velocity after the development of the photoconductive drum is completed.

Abstract: A gear mechanism is provided and includes a first sun gear; a first planetary gear configured to mesh with the first sun gear; a first arm configured to keep a distance between the first sun gear and the first planetary gear and configured to swing around a rotation axis of the first sun gear; a second sun gear; a second planetary gear configured to mesh with the second sun gear; a second arm configured to keep a distance between the second sun gear and the second planetary gear and configured to swing around a rotation axis of the second sun gear; and an interlocking unit configured to connect the first arm and the second arm with each other for interlocking the swinging of the first arm and the second arm, the interlocking unit configured to move independently of rotations of the first sun gear and the second sun gear.

Abstract: A coupling unit includes two constant velocity joints arranged in series in the shaft direction. The coupling unit couples a driven shaft and a drive shaft. Each constant velocity joint includes a ball non-retaining member and a ball retaining member. The ball non-retaining member has an annular space with one opened end and a plurality of track grooves extending in the shaft direction on an external wall surface of the annular space at a constant interval in a circumferential direction. The ball retaining member has a portion that engages with the annular space of the ball non-retaining member, and that retains a ball that slides along each of the track grooves formed in the ball non-retaining member.

Abstract: An image forming apparatus which forms an image on an image carrier along with rotation of a developing sleeve that carries a toner and carrier contained in a two-component developer, comprises: forming unit configured to form a density detection toner image on the image carrier using the toner; detection unit configured to detect a density of the density detection toner image formed; prediction unit configured to predict a toner charge amount in the two-component developer; correction unit configured to correct the toner charge amount in the two-component developer using a value obtained from a relationship between the toner charge amount predicted by the prediction unit and the density of the toner image that is detected by the detection unit; and control unit configured, when forming the density detection toner image by the forming unit, to control to increase a development efficiency, compared to image formation based on image data.

Abstract: A method for reducing high-frequency banding in an electrophotographic development station having a rotating shell and a rotating magnetic core is disclosed. A rotating angular velocity of the rotating shell is adjusted relative to a angular velocity of a photoconductor such that a ratio of these angular velocities is not a ratio of whole numbers.

Abstract: An image forming apparatus is provided that holds counter information obtained by integrating a consumption of a consumable that depends on usage of service provided by the image forming apparatus. A log corresponding to the usage of the service is set in job log information with a synchronization flag set off. The log in the job log information, for which the synchronization flag is set off, is set on. The counter information and the job log information are output after the synchronization flag for the log having the synchronization flag set off has been set on.

Abstract: An image forming apparatus includes: an image bearing member; a development device; a speed varying unit that can vary a speed of a developer bearing member; a sensing portion that senses an environmental temperature around the development device; and a controller that can perform a mode in which, compared with a period which an image forming region of the image bearing member passes through the developing region, the rotation speed of the developer bearing member slows down a period which a non-image forming region of the image bearing member passes through the developing region, wherein based on sensing result of the sensing portion, the controller performs the mode when the environmental temperature is higher than a predetermined value, and the controller does not perform the mode when the environmental temperature is lower than the predetermined value.

Abstract: A developing device includes: a plurality of developer retaining bodies that retain developer and rotate, and that respectively convey the developer, which is supplied to each of the developer retaining bodies from a developer supply section, to an image bearing body that rotates and bears a latent image; and a speed changing unit that is adapted to change a rotation speed of at least one of the developer retaining bodies excluding a developer retaining body that is furthest downstream side in a direction of rotation of the image bearing body.

Abstract: The present invention provides a method and apparatus for forming an image. A controller manages a charger and a developing bias voltage to increase an absolute value of the charging voltage to an image-bearing member and an absolute value of a developing bias voltage to a developer-bearing member to predetermined values in a plurality of steps. The controller controls the developing bias voltage applied to the developer-bearing member; wherein the following relation holds in each of the plurality of steps: |VD|>|Vi|, where VD represents a developing bias voltage applied to the developer-bearing member and Vi represents a charged potential of the image-bearing member. This invention is especially useful for mono-component development using DC voltage as a development driving mechanism.

Abstract: A developing device is disposed facing an image bearing body that bears a latent image. The developing device includes a developer bearing body that bears a developer for developing the latent image. The developer includes mother particles and external additives. A liberation amount T (weight parts) of the external additives liberated from the mother particles with respect to 100 weight parts of the mother particles, a surface roughness Rz (m) of the developer bearing body, and a circumferential speed Vd (mm/s) of the developer bearing body satisfy the following relationships: 1.326×10?1?T?2.142×10?1 (weight parts), 7.1×10?6?Rz?15.0×10?6 (m), 161.5?Vd?189.2 (mm/s), and 4.98×10?6?(T×Rz/Vd)?1.99×10?5 (s).

Abstract: An image forming apparatus includes a developer bearing body for supplying developer to a surface of the image bearing body, on which an electrostatic latent image is formed by a latent image forming unit; a driving unit for rotating the developer bearing body; a speed control unit for determining a rotation speed of the developer bearing body; a drive control unit for controlling the driving unit so that the developer bearing body rotates at the determined rotation speed; and a control unit for determining the amount of developer to be disposed of on the basis of the determined rotation speed and controlling disposal of the determined amount of developer on the surface of the developer bearing body.

Abstract: A method and device for controlling toner transfer during the formation of a toner image within an image forming device is described herein. One exemplary image forming device includes a toner reservoir that stores toner of a first color, a developer member that receives toner from the toner reservoir, a photoconductive member proximate the developer member that receives toner from the developer member, and a driver. While rotating the photoconductive member, the driver selectively rotates the developer member based on a color content of the image. For example, the driver does not rotate the developer member while rotating the photoconductive member when the toner image being formed lacks the first color. Alternatively, the driver lows the rotational speed of the developer member while rotating the photoconductive member when the toner image being formed lacks the first color.

Abstract: An image forming apparatus (100) includes a photoreceptor drum (1), a development unit (2), a pressing member (7), and a vibration absorption member (8). The development unit (2) is disposed adjacent to the photoreceptor drum (1), and supported movably toward and away from the photoreceptor drum (1). The pressing member (7) urges the development unit (2) toward the photoreceptor drum. The vibration absorption member (8) frictionally suppresses the movement of the development unit (2) toward and away from the photoreceptor drum (1). The vibration absorption member (8) attenuates a self-excited vibration of the development unit (2), by suppressing the movement of the development unit (2).

Abstract: An image formation apparatus includes a containing section that contains a developer and that has an opening at which a developer carrier is exposed. The developer carrier rotates at a faster first speed or a slower second speed. When a detected height of developer in the containing section is at a replenishment start level and the developer carrier is rotating at the first speed, a replenishing member replenishes developer until the height of the developer reaches a replenishment end level. When the detected height of developer is at the replenishment start level and the developer carrier is rotating at the second speed, the developer is replenished by a predetermined amount.

Abstract: An image forming apparatus includes an image bearing member; a developing device including a developer carrying member for supplying the developer to the image bearing member, a developer feeding member, provided rotatably in a developing container, first and second driving force receiving members, provided at opposite end portions of the developer carrying member, for driving the developer carrying member and the developer feeding member, respectively; a first and second drive inputting members, for inputting drive to the first and second driving force receiving members, respectively. Directions, toward and away from the image bearing member, of forces are applied to abutment members, which determine a gap between the image bearing member and the developer carrying member, at the time when the drives are inputted to the first driving force receiving member and the second driving force receiving member, respectively.

Abstract: A developing device includes: a developer storage portion which stores a liquid developer including toner and carrier liquid; a first coating member which rotates and coats the liquid developer stored in the developer storage portion; a second coating member which comes into contact with the first coating member and rotates in a direction opposite to that of the first coating member and slower than a rotary peripheral velocity of the first coating member; and a developer supporting body which comes into contact with the second coating member and rotates in the same direction as that of the second coating member and faster than a rotary peripheral velocity of the second coating member.

Abstract: An image forming apparatus includes an image bearing member on which an electrostatic image is formed by imagewise exposure; a rotatable member; a developing device carried on said rotatable member and movable, by rotation of said rotatable member, to a developing position where said developing device is opposed to said image bearing member; a driven gear which is provided in said developing device and which receives a driving force for operating said developing device; and a driving gear, provided in a main assembly of the apparatus, for driving engagement with said driven gear of said developing device which is located at the developing position, wherein said driving gear, when said developing device is moving toward the developing position, is driven such that moving direction thereof is the same as a moving direction of said driven gear at an engagement portion with said driven gear, wherein upon driving engagement between said driven gear and said driving gear, a peripheral speed VA of said driven gear w

Abstract: A control system for use with a development process including at least one magnetic roll with a settable speed is provided. The controller is directly or indirectly responsive to a reload feedback signal, which signal is generated in response to changes in output reload performance of the development process. In the case of direct responsiveness, the controller uses one or more reload feedback signals to facilitate magnetic roll speed setting. In the case of indirect responsiveness, the controller uses a reload sensitivity signal, which reload sensitivity signal varies as a function of input digital image content and output reload performance feedback, to facilitate magnetic roll speed setting.

Abstract: To provide an image forming device that is capable of preventing deterioration of the image quality through preventing deterioration of the toner even if frequency of making a copy is low. The image forming device includes: a developing part having a developing roller for achieving development by electrostatically attaching a toner onto an electrostatic latent image formed on a photoreceptor; a transferring part for transferring a developed toner image to a paper; and a cleaner part for removing and collecting the toner remained on the photoreceptor after transferring, wherein the developing roller is rotary-driven at a lower speed than a speed of development under a standby state. The image forming device includes a standby-state refresh control part for forcibly consuming an amount of the toner that is calculated based on accumulated time of the low-speed rotary drive.

Abstract: A driving time count is obtained by accumulating a multiplication value which is obtained by multiplying a driving time of a mixer by a coefficient corresponding to an operation of a developing roller. When the driving time count reaches a life threshold for judgment of a life of a developer, it is judged that the developer reaches its end of life.

Abstract: An image forming apparatus includes a turnable image bearing body for bearing a latent image; a turnable developer bearing body for bearing liquid developer, the developer bearing body and the image bearing body being pressed in contact with each other at a predetermined press-contact position, the developer bearing body being capable of carrying the liquid developer toward the press-contact position by turning, the image forming apparatus performing development of the latent image, which is bore by the image bearing body, with the liquid developer that has been carried toward the press-contact position; and a controller for causing the development of the latent image to start after a predetermined period of time has passed from when the turning speed of the developer bearing body and the image bearing body reached a predetermined turning speed for development at which the development is performed.

Abstract: An image forming apparatus and a method to control a velocity ratio thereof. The image forming apparatus includes a developing device to rotate opposite a photoconductive medium and to supply the photoconductive medium with a developer, and a controller to control a velocity ratio of the developing device to the photoconductive medium according to an accumulated number of printed copies.

Abstract: A control part 33 rotates a developer roller 21a at a second rotation speed, which is slower than a normal rotation speed during an image formation period (first rotation speed), during a non-image formation period while a heater 14 is in use. This prevents deformation of the developer roller 21a caused by radiant heat from a photoconductive drum 41, effectively prevents the appearance of image fogging, concentration unevenness, and the like, and also suppresses toner deterioration in a development unit 21.

Abstract: A method and device for controlling toner transfer during the formation of a toner image within an image forming device is described herein. One exemplary image forming device includes a toner reservoir that stores toner of a first color, a developer member that receives toner from the toner reservoir, a photoconductive member proximate the developer member that receives toner from the developer member, and a driver. While rotating the photoconductive member, the driver selectively rotates the developer member based on a color content of the image. For example, the driver does not rotate the developer member while rotating the photoconductive member when the toner image being formed lacks the first color. Alternatively, the driver lows the rotational speed of the developer member while rotating the photoconductive member when the toner image being formed lacks the first color.

Abstract: A control system for use with a development process including at least one magnetic roll with a settable speed is provided. The controller is directly or indirectly responsive to a reload feedback signal, which signal is generated in response to changes in output reload performance of the development process. In the case of direct responsiveness, the controller uses one or more reload feedback signals to facilitate magnetic roll speed setting. In the case of indirect responsiveness, the controller uses a reload sensitivity signal, which reload sensitivity signal varies as a function of input digital image content and output reload performance feedback, to facilitate magnetic roll speed setting.

Abstract: An image forming apparatus includes a rotatable image bearing member bearing an electrostatic image; a rotatable developer carrying member carrying a developer to develop the electrostatic image; speed controlling means for switching a rotating speed of the image bearing member between a first speed and a second speed lower than the first speed, and performing an image forming operation at each speed; and developer carrying member speed controlling means for controlling a rotating speed of the developer carrying member so that a rotating speed of the developer carrying member when the image forming operation is performed by rotating the image bearing member at the second speed, which is less than 70% of the first speed so as to be within a range of ±30% of a rotating speed of the developer carrying member when the image forming operation is performed by rotating the image bearing member at the first speed.

Abstract: An image forming apparatus includes a developer that develops a latent image to form an image, a separation unit that separates image information of a job image by color upon writing a latent image of the job image, a comparison unit that compares the image information by color separated by the separation unit with a threshold value previously set with respect to an image concentration, and a driving condition determination unit that determines a driving condition of the developer using a result of comparison by the comparison unit.

Abstract: An image forming apparatus of the present invention includes a developing device including a rotatable, nonmagnetic developer carrier and a magnetic field forming device. In a developing region where the developer carrier faces an image carrier, the magnetic field forming device causes a developer made up of toner and magnetic grains to rise on the developer carrier in the form of a magnet brush. In the developing region, the magnet brush on the developer carrier is caused to move at a higher speed than the surface of the image carrier in the same direction as and in contact with the surface of the image carrier, thereby developing the latent image. The toner of the developer is magnetic toner. Flux density set up in the developing region outside of the surface of the developer carrier in a normal direction has an attenuation ratio of 50% or above.

Abstract: A developer driving apparatus which drives a plurality of developing rollers via a gear chain including pivotable gears and one way gears. A reversible driving motor is coupled to a deceleration gear which directly drives a first swing drive gear and drives a second swing drive gear via an odd number of idler gears. Each swing drive gear is rotationally coupled with a respective swing gear having a center of rotation which is pivotable about a center of rotation of the respective swing drive gear. In a first position each swing gear drives one of the plurality of rollers via a respective one way gear and in a second position, each swing gear drives another of the plurality of rollers via a respective one way gear. A solenoid activated lever moves each swing gear between respective first and second positions.

Abstract: An image forming apparatus includes an image bearing member and a developer carrying member, which carries a developer to develop an electrostatic image formed on the image bearing member with the developer. In a non-developmental time period, a peripheral velocity of the developer carrying member is slower than the peripheral velocity of the developer carrying member during a developmental time period. In addition, a peripheral velocity of the image bearing member during the non-developmental time period is slower than the peripheral velocity of the image bearing member during the development time period.

Abstract: An image-forming apparatus includes a developing roller and a developing blade. The developing blade applies toner to the developing roller to form a thin layer of toner on the developing roller. The image-forming apparatus performs a printing operation that includes a paper-feeding period and a developing period following the paper-feeding period. The developing roller rotates relative to the developing blade at a first speed during the paper-feeding period and then at a lower second speed than during the developing period, thereby eliminating chance of white lines of occurring in a printed image. The developing roller may be rotated at a constant speed in each printing operation until the circumferential surface of the developing roller has traveled over a certain cumulative distance. When the surface has traveled over the first distance, the developing roller may be rotated at an increased speed over a certain distance.