Abstract: A process unit includes: a photosensitive drum on a surface of which a toner image is formed; a charging roller being pressed against the photosensitive drum so as to charge the photosensitive drum; a cleaning roller being pressed against the charging roller so as to clean the charging roller; and at least one biasing member biasing the charging roller or the cleaning roller. A central axis of the photosensitive drum is located at a position not overlapping with a central axis line passing through a central axis of the charging roller and a central axis of the cleaning roller. A biasing direction of the at least one biasing member is on a same line as the central axis line.

Abstract: A process unit includes: a photosensitive drum on a surface of which a toner image is formed; a charging roller being pressed against the photosensitive drum so as to charge the photosensitive drum; a cleaning roller being pressed against the charging roller so as to clean the charging roller; and at least one biasing member biasing the charging roller or the cleaning roller. A central axis of the photosensitive drum is located at a position not overlapping with a central axis line passing through a central axis of the charging roller and a central axis of the cleaning roller. A biasing direction of the at least one biasing member is on a same line as the central axis line.

Abstract: In an image forming apparatus, a cleaning portion has a discharge pipe that guides toner that has been collected from a peripheral surface of a photoreceptor drum as waste toner to the outside of a process unit. The discharge pipe is drawn from a side surface of the process unit and includes at a tip portion a discharge port that discharges the waste toner. A restricting portion is arranged on a side surface of the discharge pipe, between a position corresponding to an insertion port and the discharge port, and restricts a flow of air moving from the discharge port to the insertion port. The insertion port is provided on a same surface as the side surface of the process unit from which the discharge pipe is drawn. And the insertion port is configured to be inserted by a cleaning tool for the electrode.

Abstract: To provide a charging device which can be reduced in size and increased in speed while suppressing the occurrence of charging irregularities on the surface of the photosensitive drum, a process cartridge, and an image forming apparatus.

Abstract: In an image forming apparatus, a cleaning portion has a discharge pipe that guides toner that has been collected from a peripheral surface of a photoreceptor drum as waste toner to the outside of a process unit. The discharge pipe is drawn from a side surface of the process unit and includes at a tip portion a discharge port that discharges the waste toner. A restricting portion is arranged on a side surface of the discharge pipe, between a position corresponding to an insertion port and the discharge port, and restricts a flow of air moving from the discharge port to the insertion port. The insertion port is provided on a same surface as the side surface of the process unit from which the discharge pipe is drawn. And the insertion port is configured to be inserted by a cleaning tool for the electrode.

Abstract: To provide a charging device which can be reduced in size and increased in speed while suppressing the occurrence of charging irregularities on the surface of the photosensitive drum, a process cartridge, and an image forming apparatus.

Abstract: An exhaust device provided in an image forming apparatus is provided. In the exhaust device, an initial condition setting unit sets an initial drive output value of a exhaust fan at a time of starting an image forming operation based on a calculation value calculated by an image bearing member drive counting unit. A drive unit drives the exhaust fan to start to discharge air in the image forming apparatus. A continuation condition setting unit sets a continuation drive condition at a time of continuously driving the exhaust fan from a point in time when ending the image forming operation based on a count value of the number of image formation by the job counting unit 303a. A drive unit drives the exhaust fan with the continuation drive condition to continuously discharge the air in the image forming apparatus.

Abstract: An object of the present invention is to provide a charging roller (i) which includes a rubber member whose surface is subjected to a hardening treatment using a solvent containing at least an isocyanate compound and (ii) which can prevent leakage of an ionic conductive agent even if the charging roller is placed under conditions of high temperature and high humidity for a long time. The charging roller is made by forming a rubber layer on a metal core. The rubber layer is an epichlorohydrin based rubber base material to which an ionic conductive agent is added, the rubber layer being subjected to a surface treatment by applying a solution containing the isocyanate compound and heating it. This surface treatment is carried out under such conditions that a coefficient of dynamic friction at a contact portion between the rubber layer and a photoreceptor becomes 0.4 or less.

Abstract: A cleaning device 70 includes: contact and release system 63 which switches a position of a cleaning roller 62 between a position where the cleaning roller 62 is in contact with a charging roller 61 and a position where the cleaning roller 62 is separated from the charging roller 61; and a voltage selecting section 71 which switches a voltage to be applied to the charging roller 61 from a DC voltage to an AC voltage during the rotation of a photoreceptor 11. The contact and release system 63 brings the cleaning roller 62 into contact with the charging roller 61 at the application of the AC voltage to the charging roller 61. This makes it possible to enhance performance on cleaning of the charging roller.

Abstract: An image forming apparatus in which a charging roller charges an image carrier to which a lubricant is applied prevents slip of the charging roller. The charging roller is composed of a metal core and a rubber layer mainly made of an epichlorohydrin rubber formed around the metal core. A surface of this rubber layer is hardened with a surface treating solution containing an isocyanate compound. The surface of this rubber layer is also subjected to three abrading processes including two stone grinding processes and one lapping process so that a ten-point height of irregularities Rz thereof becomes 11 ?m or more.

Abstract: An exhaust device provided in an image forming apparatus is provided. In the exhaust device, an initial condition setting unit sets an initial drive output value of a exhaust fan at a time of starting an image forming operation based on a calculation value calculated by an image bearing member drive counting unit. A drive unit drives the exhaust fan to start to discharge air in the image forming apparatus. A continuation condition setting unit sets a continuation drive condition at a time of continuously driving the exhaust fan from a point in time when ending the image forming operation based on a count value of the number of image formation by the job counting unit 303a. A drive unit drives the exhaust fan with the continuation drive condition to continuously discharge the air in the image forming apparatus.

Abstract: When image forming is performed by a photosensitive drum according to operating conditions corresponding to an image forming mode selected out of a predetermined plurality of candidates, an actual cumulative number of printed sheets Pi is corrected and recorded based on the image forming mode (monochrome mode or color mode; low-temperature and low humidity ambience mode or other ambience mode) selected at the time of each image forming (S7) and an adjustment volume (ko×Pia) of a charging applied voltage Ey is calculated and the charging applied voltage Ey is set based on a corrected cumulative number of printed sheets Pia (S5). As a result, the charging applied voltage Ey to a charging unit is changed according to a cumulative number of printed sheets and at the same time, a pace of change thereof is adjusted based on the image forming mode.

Abstract: The invention delivers a charging roller which is capable of preventing current leakage to a photoreceptor throughout life-time and which has a stable resistance value throughout life-time. The charging roller contains a metal core and a rubber layer formed on the core. The rubber layer is an epichlorohydrin-based rubber base material to which an electronic conductive agent and an ionic conductive agent are added. The rubber layer is subjected to surface processing by spraying the surface with a solution containing an isocyanate compound and heating. The amount of the electronic conductive agent added to the rubber base material is limited so that a volume resistivity when only the electronic conductive agent is added to the rubber base material is 1.46×106 ?·cm or greater. In addition, the amount of the added ionic conductive agent is increased so that a volume resistivity when the electronic conductive agent and the ionic conductive agent are added to the rubber base material is 1.93×106 ?·cm or less.

Abstract: An object of the present invention is to provide a charging roller (i) which includes a rubber member whose surface is subjected to a hardening treatment using a solvent containing at least an isocyanate compound and (ii) which can prevent leakage of an ionic conductive agent even if the charging roller is placed under conditions of high temperature and high humidity for a long time. The charging roller is made by forming a rubber layer on a metal core. The rubber layer is an epichlorohydrin based rubber base material to which an ionic conductive agent is added, the rubber layer being subjected to a surface treatment by applying a solution containing the isocyanate compound and heating it. This surface treatment is carried out under such conditions that a coefficient of dynamic friction at a contact portion between the rubber layer and a photoreceptor becomes 0.4 or less.

Abstract: A cleaning device 70 includes: contact and release system 63 which switches a position of a cleaning roller between a position where the cleaning roller 62 is in contact with a charging roller 61 and a position where the cleaning roller 62 is separated from the charging roller 61; and a voltage selecting section 71 which switches a voltage to be applied to the charging roller 61 from a DC voltage to an AC voltage during the rotation of a photoreceptor 11. The contact and release system 63 brings the cleaning roller 62 into contact with the charging roller 61 at the application of the AC voltage to the charging roller 61. This makes it possible to enhance performance on cleaning of the charging roller.

Abstract: An object of the present invention is to provide a charging roller (i) which includes a rubber member whose surface is subjected to a hardening treatment using a solvent containing at least an isocyanate compound and (ii) which can prevent leakage of an ionic conductive agent even if the charging roller is placed under conditions of high temperature and high humidity for a long time. The charging roller is made by forming a rubber layer on a metal core. The rubber layer is an epichlorohydrin based rubber base material to which an ionic conductive agent is added, the rubber layer being subjected to a surface treatment by applying a solution containing the isocyanate compound and heating it. This surface treatment is carried out under such conditions that a coefficient of dynamic friction at a contact portion between the rubber layer and a photoreceptor becomes 0.4 or less.

Abstract: The invention delivers a charging roller which is capable of preventing current leakage to a photoreceptor throughout life-time and which has a stable resistance value throughout life-time. The charging roller contains a metal core and a rubber layer formed on the core. The rubber layer is an epichlorohydrin-based rubber base material to which an electronic conductive agent and an ionic conductive agent are added. The rubber layer is subjected to surface processing by spraying the surface with a solution containing an isocyanate compound and heating. The amount of the electronic conductive agent added to the rubber base material is limited so that a volume resistivity when only the electronic conductive agent is added to the rubber base material is 1.46×106 ?·cm or greater. In addition, the amount of the added ionic conductive agent is increased so that a volume resistivity when the electronic conductive agent and the ionic conductive agent are added to the rubber base material is 1.93×106 ?·cm or less.

Abstract: An image forming apparatus in which a charging roller charges an image carrier to which a lubricant is applied prevents slip of the charging roller. The charging roller is composed of a metal core and a rubber layer mainly made of an epichlorohydrin rubber formed around the metal core. A surface of this rubber layer is hardened with a surface treating solution containing an isocyanate compound. The surface of this rubber layer is also subjected to three abrading processes including two,stone grinding processes and one lapping process so that a ten-point height of irregularities Rz thereof becomes 11 ?m or more.

Abstract: In an image forming apparatus in which a charging roller charges a photoreceptor which is rotating at high speed, damages of the photoreceptor and the charging roller are prevented. The photoreceptor included in an electrophotographic image forming apparatus is rotated at high speed so that a speed of a peripheral surface of the photoreceptor is 225 mm per second or more. Then, the charging roller is rotated by contacting the photoreceptor, so as to charge the photoreceptor. Here, a surface pressure M of a contact portion between the photoreceptor and the charging roller is set to more than 0.8 g/mm2 but not more than 3.5 g/mm2.

Abstract: An image forming method, device and a recording agent for forming an image through subtractive color mixing by using ink of plural color components different in hue. The ink is created by mixing a first coloring agent expressing one of the color components and a second coloring agent identical in hue to the first coloring agent. The ink has a higher spectral reflectance than a spectral reflectance of the first coloring agent.