Canon Kabushiki Kaisha

Yuya Nagatomo

Takeshi Fujino

Jiro Kinokuni

Michihiro Yoshida

Kota Mori

Noriyuki Okada

Shozo Aiba

Naoki Mugita

Kenta Matsuzaki

Akinori Miyamoto

Masato Maejima

An image forming apparatus includes a photosensitive member, a charging member configured to charge a surface of the photosensitive member, a power supply configured to apply the DC voltage to the charging member, a current detection unit configured to detect a current value flowing from the charging member to the photosensitive member, a calculation unit configured to calculate a first voltage value based on applied voltages with different voltage values and detected current values, and a setting unit configured to set a second voltage value to be applied to the charging member during forming of an image. The setting unit sets the second voltage value by adding the first voltage value, a target voltage value, and a correction value corresponding to a peripheral speed of the photosensitive member during forming of the image.

Image forming apparatus that adjusts voltage for charging photosensitive member

In an image forming apparatus, a cleaning blade, disposed on a downstream side of a transfer roller in a rotation direction of an image carrier, removes toner remaining on the image carrier after transfer of a toner image to an intermediate transfer member. After completion of an image forming operation, a controller causes the transfer roller to separate from the intermediate transfer member, cause the developing device to form on the image carrier a toner band to be supplied to the cleaning blade, and cause rotation of the image carrier to stop such that at least a part of the toner band formed on the image carrier stops within a section from a first position facing the transfer roller to a second position facing the cleaning blade in the rotation direction.

Image forming apparatus

An image forming apparatus includes a photosensitive member, a charging roller, a cleaning roller, an urging member and an image forming portion. The charging roller has an outermost surface layer including an electroconductive resin material, first surface particles having an average particle size of more than 7 &#x3bc;m and less than 30 &#x3bc;m and second surface particles having an average particle size of more than 2 &#x3bc;m and less than 6 &#x3bc;m. The first and second surface particles are dispersed in the electroconductive resin material so as to form first projections and second projections, respectively. The cleaning roller cleaning roller includes a shaft portion and an elastic cleaning portion extending helically around the shaft portion and having a rectangular cross-section perpendicular to an extending direction thereof.

Image forming apparatus and cartridge having a charging roller with a surface layer including projections

An image forming apparatus includes a photosensitive member having a surface having elastic deformation power of 47% or more, a charging roller forming a nip between itself and the photosensitive member, and an image forming portion. When a nip region corresponding to the nip is formed and then an area of independent contact portions between the charging member and a measuring contact member is measured, the following relationship is satisfied: (contact width X)&#xd7;(Contact area ratio &#x3b1;)&#x2264;0.1, where a length from a position of one end to a position of the other end of the nip region with respect to a direction perpendicular to a longitudinal direction of the charging roller is the contact width X, and a ratio of a sum of areas of the independent contact portions to an entire area of a measuring region is the contact area ratio &#x3b1;.

Image forming apparatus and cartridge having charging roller

A charging roller includes a surface layer containing first and second surface particles and satisfying the following:6.0 (&#x3bc;m)&#x2264;&#x2264;18.8 (&#x3bc;m),&#x2003;&#x2003;iwhere Rz is a ten-point average roughness (&#x3bc;m) of a charging roller surface,7 (&#x3bc;m)&#x2264;&#x2264;20 (&#x3bc;m),&#x2003;&#x2003;iiwhere d is a thickness (&#x3bc;m) of the surface layer,9.8 (&#x3bc;m)&#x2264;1&#x2264;15.8 (&#x3bc;m) and 2.8 (&#x3bc;m)&#x2264;2&#x2264;5.2 (&#x3bc;m),&#x2003;&#x2003;iiiwhere D1 and D2 are average particle size (&#x3bc;m) of the first surface particles, and the second surface particles, respectively,3.0&#x2264;1/2&#x2264;5.6, and&#x2003;&#x2003;iv0.10&#x2264;1/(1+2)&#x2264;0.32,&#x2003;&#x2003;vwhere M1 is a total weight (mg) of the first surface particles per unit area of the charging roller surface, and M2 is a total weight (mg) of the second surface particles per unit area of the charging roller surface.

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Toride, Japan

Yuya Nagatomo