Abstract: The present disclosure provides a method for detecting a biomolecule. The method includes providing an electrode 101 and an aptamer 102 that specifically binds to a target biomolecule and has a charge, the aptamer 102 being disposed near the electrode 101; introducing a cationic mediator 113 having a charge opposite to the charge of the aptamer 102 to the electrode 101 at which the aptamer 102 is disposed; bringing a solution containing the target biomolecule into contact with the aptamer 102 to cause the aptamer 102 to bind to the biomolecule; and measuring an electrical signal that is produced at the electrode 101 in association with the cationic mediator 113.

Abstract: A first bias Vslv is applied to a development roller 22 and a second bias Vmag is applied to a magnetic roller 23 to perform development; after completion of development, without changing the setting of Vslv, of the AC component Vpp2 of Vmag, the peak voltage value Vpp2 (max) at the side with the same polarity as toner is made lower than during a development period and development-residual toner on the development roller 22 is collected to prevent a lateral streak formed on photoconductor drums 1a to 1d during a non-development period.

Abstract: A developing unit has a voltage-applicator (80) to apply a developing bias voltage to a developing roller (72). The voltage-applicator (80) applies the developing bias voltage for a first duration to apply an AC voltage having a rectangular waveform, and a second duration to stop applying the AC voltage. The AC voltage has a duty ratio of 50% or more in a direction for causing toner to develop an electrostatic latent image. The number of cycles of the AC voltage in the first duration is two or more, and the AC voltage has a voltage in a direction for pulling the toner back to the developing roller, just before transition to the second duration. The developing unit suppresses occurrence of image unevenness due to a fluctuation in developing gap. Thus, an image forming apparatus equipped with the developing unit forms a high-quality image while suppressing image unevenness.

Abstract: An image forming apparatus is provided with a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image formed on the photoconductive member by a first bias, and a magnetic roller for forming a magnetic brush thereon with a two-component developer and forming a thin toner layer on the developing roller by a second bias. If (D1) denotes the duty ratio of a first alternating-current bias included in the first bias and (D2) denotes the duty ratio of a second alternating-current bias included in the second bias, the duty ratios (D1, D2) satisfy the following relationship: D1>100?D2.

Abstract: A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.

Abstract: An image forming apparatus has a photoconductive member, and a developing roller develops a latent image on the photoconductive member by a first alternating-current bias in the form of a rectangular wave. The following relationships are satisfied in calculating the duty ratio (D1) of the first alternating-current bias using an application period of voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: a CV value in the number particle size distribution of the toner is ?25%, 4 ?m?Dt?7 ?m, 105 ?·cm?pv?109 ?·cm, 0.4 ?m?Ra?1.5 ?m, and 35%?D1?75%. where Dt denotes the volume average particle diameter of the toner, pv denotes the intrinsic resistance value of a developing roller surface, Ra denotes the arithmetic average roughness of the developing roller surface.

Abstract: A developing unit includes a development roller and a magnetic roller. Sleeves of the development roller and the magnetic roller are driven to rotate in the same circumferential direction. A first magnet is provided on the roller shaft in the sleeve of the development roller and a second magnet is provided on the roller shaft in the sleeve of the magnetic roller. The first and second magnets are opposed to each other so that opposite polarities face each other, and are supported non-rotatably in circumferential directions. The first magnet is supported so that the peak of the magnetic force of the first magnet is positioned upstream in the direction of rotation of the sleeve of the development roller from the straight line connecting the center of the roller shaft of the development roller to the center of the roller shaft of the magnetic roller.

Abstract: An image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D1) of the first alternating-current bias satisfy relationships of the following equations for calculating the duty ratio (D1) using an application period of a voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: 7 ?m?T?13 ?m, and 35%?D1?70%.

Abstract: An image forming apparatus uses a two-component developer containing a toner and a carrier. The apparatus has a latent image bearer for bearing an electrostatic latent image. A toner bearer bears the toner to be conveyed to a development region to develop the electrostatic latent image. A developer bearer bears the two-component developer and supplies the toner to the toner bearer. A regulator sets the thickness of a toner layer carried on the toner bearer to 6 ?m to 15 ?m and sets a difference between a half width of a first toner charge number distribution as a number distribution of the charge amount of the toner carried on the toner bearer and that of a second toner charge number distribution as a number distribution of the charge amount of the toner in the two-component developer carried on the developer bearer to 0.8 (10?10 C/m) or smaller.

Abstract: A first bias Vslv is applied to a development roller 22 and a second bias Vmag is applied to a magnetic roller 23 to perform development; after completion of development, without changing the setting of Vslv, of the AC component Vpp2 of Vmag, the peak voltage value Vpp2 (max) at the side with the same polarity as toner is made lower than during a development period and development-residual toner on the development roller 22 is collected to prevent a lateral streak formed on photoconductor drums 1a to 1d during a non-development period.

Abstract: An image forming apparatus uses a two-component developer containing a toner and a carrier. The apparatus has a latent image bearer for bearing an electrostatic latent image. A toner bearer bears the toner to be conveyed to a development region to develop the electrostatic latent image. A developer bearer bears the two-component developer and supplies the toner to the toner bearer. A regulator sets the thickness of a toner layer carried on the toner bearer to 6 ?m to 15 ?m and sets a difference between a half width of a first toner charge number distribution as a number distribution of the charge amount of the toner carried on the toner bearer and that of a second toner charge number distribution as a number distribution of the charge amount of the toner in the two-component developer carried on the developer bearer to 0.8 (10?10 C/m) or smaller.

Abstract: A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.

Abstract: An image forming apparatus is characterized in that an absolute value of a difference between a first coefficient of variation in a number distribution of the particle diameter of a toner carried on a developing roller and a second coefficient of variation in a number distribution of the particle diameter of a toner in a two-component developer carried on the magnetic roller is within 5% and an absolute value of a difference between a third coefficient of variation in a number distribution of the particle diameter of a toner of a toner image developed on the outer surface of an image bearing member and the second coefficient of variation is within 6%. With such an image forming apparatus, high-quality images can be stably formed over a long term.

Abstract: An image forming apparatus has a photoconductive member, and a developing roller develops a latent image on the photoconductive member by a first alternating-current bias in the form of a rectangular wave. The following relationships are satisfied in calculating the duty ratio (D1) of the first alternating-current bias using an application period of voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: a CV value in the number particle size distribution of the toner is ?25%, 4 ?m?Dt?7 ?m, 105 ?·cm?pv?109 Q?cm, 0.4 ?m?Ra?1.5 ?m, and 35%?D1?75%. where Dt denotes the volume average particle diameter of the toner, pv denotes the intrinsic resistance value of a developing roller surface, Ra denotes the arithmetic average roughness of the developing roller surface.

Abstract: An image forming apparatus is provided with a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image formed on the photoconductive member by a first bias, and a magnetic roller for forming a magnetic brush thereon with a two-component developer and forming a thin toner layer on the developing roller by a second bias. If (D1) denotes the duty ratio of a first alternating-current bias included in the first bias and (D2) denotes the duty ratio of a second alternating-current bias included in the second bias, the duty ratios (D1, D2) satisfy the following relationship: D1>100?D2.

Abstract: An image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D1) of the first alternating-current bias satisfy relationships of the following equations for calculating the duty ratio (D1) using an application period of a voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: 7 ?m?T?13 ?m, and 35%?D1?70%.

Abstract: A developing unit has a voltage-applicator (80) to apply a developing bias voltage to a developing roller (72). The voltage-applicator (80) applies the developing bias voltage for a first duration to apply an AC voltage having a rectangular waveform, and a second duration to stop applying the AC voltage. The AC voltage has a duty ratio of 50% or more in a direction for causing toner to develop an electrostatic latent image. The number of cycles of the AC voltage in the first duration is two or more, and the AC voltage has a voltage in a direction for pulling the toner back to the developing roller, just before transition to the second duration. The developing unit suppresses occurrence of image unevenness due to a fluctuation in developing gap. Thus, an image forming apparatus equipped with the developing unit forms a high-quality image while suppressing image unevenness.

Abstract: A developing unit includes a development roller and a magnetic roller. Sleeves of the development roller and the magnetic roller are driven to rotate in the same circumferential direction. A first magnet is provided on the roller shaft in the sleeve of the development roller and a second magnet is provided on the roller shaft in the sleeve of the magnetic roller. The first and second magnets are opposed to each other so that opposite polarities face each other, and are supported non-rotatably in circumferential directions. The first magnet is supported so that the peak of the magnetic force of the first magnet is positioned upstream in the direction of rotation of the sleeve of the development roller from the straight line connecting the center of the roller shaft of the development roller to the center of the roller shaft of the magnetic roller.

Abstract: The electrophotographic image formation apparatus of the present invention adopts a developer roller, which is made of aluminum and has an aluminum oxide film of at least 5 ?m in thickness formed on surface thereof. In the image formation apparatus, a gap between the developer roller and a photoreceptor drum 3 is set in a range of 150 to 300 ?m. The image formation method of the present invention regulates a frequency of AC voltage in a non-development state to be higher than that in a development state, when an AC voltage is applied onto the developer roller to cause flight of toner from the developer roller to the photoreceptor, and selectively makes charged toner fly onto the electrostatic latent image for development. The present invention provides the effective development technique to prevent leakage of the applied voltage between the developer roller and the photoreceptor drum.

Abstract: An image forming apparatus of non-contact developing method using two-component developer material which is capable of obtaining a clear image free from fogging, ghost and toner contamination. The image forming apparatus has at least one developing unit which includes a developing roll and a magnetic roll, the developing unit develops an electrostatic latent image on a photosensitive body with a toner thin layer formed on the surface of a developing roll wherein a toner thin layer forming region on the developing roll is smaller than a magnetic brush forming region on the magnetic roll. A high resistivity region is adjacent each end of the toner thin layer forming region on the developing roll. A control device controls a developer material replenishment and controls the biasing to the developing roll and magnetic roll.