Canon Kabushiki Kaisha

Ken Yokoyama

Shuji Saito

Koujirou Izumidate

Shun-ichi Ebihara

Hiroyuki Seki

Yasutaka Yagi

Masatake Usui

Shuichi Tetsuno

Kazushi Ino

Hiroto Hasegawa

Taisuke Minagawa

Masaru Tsukada

Yusaku Iwasawa

Kuniaki Kasuga

Hiroyuki Kadowaki

Hirotaka Shiomichi

Masatsugu Toyonori

Noriaki Egawa

Ryuhei Shoji

Yasuharu Hirado

Seiji Nakahara

Tsubasa Takeuchi

Akihito Sonoda

An image forming apparatus includes an image carrier to carry a toner image, intermediate, primary, and secondary transfer members, and a voltage application member. The voltage application member applies a voltage to the image carrier. The secondary transfer member is in contact with an outer circumferential surface of the intermediate transfer member. The toner image carried on the image carrier is primarily transferred onto the intermediate transfer member in a state where the voltage application member applies the voltage to the image carrier. The intermediate transfer member has a volume resistivity from 5×10Ω·cm to 2×10Ω·cm inclusive. A relation ρs1/ρs2≥1.5 is satisfied, where ρs1 denotes a surface resistivity which is measured from the outer circumferential surface of the intermediate transfer member and ρs2 denotes a surface resistivity which is measured from an inner circumferential surface of the intermediate transfer member.

Image forming apparatus

An image forming apparatus includes an intermediate transfer member. The intermediate transfer member includes a layer made of an acrylic copolymer. A plurality of grooves is formed in the layer along a moving direction of the intermediate transfer member across a width direction of the intermediate transfer member. A groove distance that is an average distance between adjoining grooves of the plurality of grooves in the width direction of the intermediate transfer member is 2 &#x3bc;m or more and 10 &#x3bc;m or less.

Image forming apparatus that improves contact member durability and suppresses occurrence of cleaning failure

An image forming apparatus includes image bearing members, an intermediary transfer member having ion conductivity, primary transfer members, a first voltage applying portion, a secondary transfer member, a second voltage applying portion, and a controller. On the basis of image information, the controller controls a transfer voltage applied to the secondary transfer member so as to be different between a first voltage when a first region, in which a coverage indicating a ratio occupied by an image region per predetermined area is a first coverage passes through the secondary transfer portion and a second voltage when a second region, in which the coverage is a second coverage larger than the first coverage, passes through the secondary transfer portion. The controller controls a change amount of the first voltage with respect to the second voltage so as to be different between a first mode and a second mode.

Image forming apparatus capable of suppressing maldistribution of an ion conductive agent on an intermediary transfer member

An image forming apparatus includes an image forming portion configured to form a toner image on an image bearing member; an intermediate transfer member onto which the toner image is transferred from the image bearing member in a primary transfer portion to form an image portion; and a control portion configured to perform control to form a toner image for lubrication in a non-image portion of the intermediate transfer member onto which the toner image for a print image based on image information is not to be formed. In a state in which the non-image portion is to be formed downstream of the image portion in a movement direction of the surface of the intermediate transfer member, the control portion performs control to change a size of a region for forming the toner image for lubrication based on the image information.

A primary transfer roller is disposed upstream or downstream from the center of rotation of a photosensitive drum in the moving direction of an intermediate transfer belt. The primary transfer roller includes a core metal and an elastic layer coating the outer circumference of the core metal and having a thickness of less than 2.0 mm. The primary transfer roller has an Asker-C hardness of 40&#xb0; or higher and 85&#xb0; or lower.

Image forming apparatus with image bearing member and a belt that contact each other to form a wound area by urging a transfer member toward the image bearing member

An image forming apparatus including: a movable intermediate transfer member onto which a toner image borne by an image bearing member is to be transferred; a detection unit configured to irradiate the toner image on the intermediate transfer member with light to detect reflected light; and a control unit configured to adjust a condition for forming the toner image based on a detection result of the detection unit, wherein a plurality of grooves extending along a movement direction of the intermediate transfer member are formed in a surface of the intermediate transfer member in a width direction intersecting the movement direction, and wherein grooves, formed within a range of the intermediate transfer member to which the light is irradiated by the detection unit, among the plurality of grooves are formed so that intervals each between adjacent grooves with respect to the width direction are regularly changed within a predetermined range.

Image forming apparatus and intermediate transfer member

A controller controls a secondary transfer power source such that a current having a first value flows in a secondary transfer portion in a case where a transfer material with an image formed on a first surface thereof has been conveyed for less than a predetermined amount of time in a second conveyance path. Moreover, the controller controls the secondary transfer power source such that a current having a second value larger in absolute value than the first value flows in the secondary transfer portion in a case where the transfer material with an image formed on the first surface thereof is conveyed to the secondary transfer portion after waiting for the predetermined amount of time or more in the second conveyance path.

An intermediate transfer belt includes, on a surface in contact with a photosensitive drum and a cleaning blade, a plurality of grooves formed along a moving direction of the intermediate transfer belt in a width direction which intersects the moving direction of the intermediate transfer belt. Further, the intermediate transfer belt includes a plurality of first regions in which adjacent grooves in the width direction are arranged at a predetermined interval, and a second region which is positioned between the plurality of first regions and in which an interval between adjacent grooves in the width direction is different from the predetermined interval. The second region is arranged outside, in the width direction of the intermediate transfer belt, a range in which a patch toner is to be formed in concentration correction.

In an image forming apparatus, a peripheral velocity difference is provided between a peripheral velocity of an intermediate transfer belt and a peripheral velocity of an image bearing member, and when a relative moving distance between the image bearing member and the intermediate transfer belt, which is generated in the transfer nip portion because of the peripheral velocity difference, is taken as a shift amount of the toner image, a lower limit value of the shift amount is set to be at least &#x215c;, preferably half of an average perimeter calculated from a weight-average particle diameter of the toner, which is measured in advance.

The image forming apparatus includes a CPU capable of executing neutralization control in which, prior to image formation, a potential difference between a voltage applied to a transfer roller by a transfer power supply and a voltage applied to a neutralization needle by a neutralization power supply is gradually increased, and a value of the potential difference when the value detected by the neutralization current meter exceeds a threshold is stored, and in which, during image formation, a value of the voltage applied by the neutralization power supply is controlled based on the stored potential difference and the value of an image formation voltage applied by the transfer power supply.

The color image forming apparatus includes a CPU configured to correct a result of detecting a toner patch by a density sensor based on a result of detecting a first white reference plate by the density sensor, and to control a density or chromaticity of a toner image based on a result of detecting the toner patch by the density sensor corrected by the CPU. The CPU is configured to further correct the result of detecting the first white reference plate by the density sensor based on a result of detecting, by the density sensor, a second white reference plate for correcting the first white reference plate. With this configuration, a correction of a sensor output is performed with high accuracy, and detection accuracy of the density or the chromaticity by the sensor is enhanced.

Color image forming apparatus

An image forming apparatus uses the difference in time taken for each patch to reach a color sensor, which occurs upon reversing the conveyance direction of a printing material. Due to this difference in time, the temperature of the printing material in detection by the color sensor differs among the respective patches. The error of a colorimetric value due to thermochromism is reduced by placing a patch with a colorimetric value which has a low temperature dependence so as to be detected earlier, and a patch with a colorimetric value which has a high temperature dependence so as to be detected later.

Color image forming apparatus having function of obtaining color information of patch

The image forming apparatus is capable of changing a state between a first state in which only a first image bearing member and transfer belt contact each other, and a second state in which respective image bearing members are separated from the transfer belt. A second transfer member is located at a first separating portion at which the second transfer member is separated from the image bearing member in the first state, and is located at a second separating position closer to the second image bearing member than the first separating position in the second state to regulate the position of the transfer belt.

An image forming apparatus includes a detection unit configured to irradiate a patch image formed on a recording material with light, and detect light intensities at a plurality of wavelengths in the light reflected from the patch image; and a determination unit configured to determine that a patch image for which the detection unit is detecting light intensities has transitioned from a first patch image to a second patch image, wherein the determination unit is further configured to determine that the patch image for which the detection unit is detecting has transitioned, in a case where a light intensity at a wavelength for identification of a patch image to be identified, has varied by an amount greater than a first threshold corresponding to that wavelength for identification.

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Mishima, Japan

Ken Yokoyama