Ricoh Company, Ltd.

Kouji Amanai

Toshiyuki Uchida

Joh Ebara

Keisuke Sugiyama

Noriaki Funamoto

Yasuhisa Ehara

Kazuhiko Kobayashi

Seiichi Handa

Yuji Matsuda

Narumi Sugita

Yohei Miura

Kenji Tomita

Kazuhiro Kobayashi

Kimiharu Yamazaki

Kobayashi Kazuhiko

Sugiyama Keisuke

Handa Seiichi

Matsuda Yuji

An image forming apparatus includes a recording medium transport belt which is suspended by a plurality of roller members. An image is secondarily transferred from a first image carrier through an intermediate transfer body to a recording medium. An image is directly transferred from a second image carrier to the recording medium. The image forming apparatus further includes a pattern image sensing unit which senses a pattern image transferred from the first image carrier and the second image carrier finally to the recording medium transport belt. Each of a distance from a secondary transfer position to a sensing position and a distance from a direct transfer position to the sensing position in a recording medium transport belt rotation direction is a natural number times a circumferential length of a roller member causing a speed change in the recording medium transport belt among the plurality of roller members.

Image forming apparatus

An image forming apparatus includes a plurality of image bearing members, each of which is configured to bear a portion of a pattern image including a plurality of reference images in a given form, an endless moving member facing the plurality of image bearing members and configured to receive the pattern image, an image detecting unit configured to detect the plurality of reference images, a rotational angle detecting unit configured to separately detect each image bearing member at a given rotational angle, and a controller configured to detect a speed deviation pattern for each revolution of each image bearing member. The controller is configured to detect the speed deviation pattern based on a result obtained from a phase component and a quadrature component of a frequency signal generated from the detection result obtained by the rotational angle detecting unit and a result of detecting the plurality of reference images in the pattern image transferred onto the endless moving member.

Image forming apparatus and image forming method of effectively detecting a speed deviation pattern of the image forming apparatus

An image forming apparatus includes a first image carrier facing an intermediate transfer belt, a primary transfer unit primarily transferring images on the first image carrier onto the intermediate transfer belt, a secondary transfer roller facing the intermediate transfer belt secondarily transferring images on the intermediate transfer belt onto a recording medium, a second image carrier provided upstream/downstream of a secondary transfer position in a recording medium conveying direction, a direct transfer unit directly transferring images on the second image carrier onto the recording medium, a recording medium carriage belt rotatably stretched across roller members including the secondary transfer roller supporting and conveying the recording medium to pass a direct transfer position and the secondary transfer position, and a displacement unit displacing the secondary transfer roller between a contact position where the recording medium carriage belt contacts the intermediate transfer belt and a separate position where it is separated therefrom.

An image forming apparatus includes a primary transfer device that primarily transfers a first image from a first image bearer onto a first belt unit at a primary transfer position, a secondary transfer device that secondarily transfers the first image from the first belt unit onto a printing medium at a secondary transfer position, and a direct transfer device that directly transfers a second image from a second image bearer onto the printing medium at a direct transfer position. A second belt unit is rotatably suspended by plural second rollers and carries and conveys the printing medium through the direct transfer position and the secondary transfer position. An interval between the direct transfer position and the secondary transfer position is prescribed natural number times of a circumference of one of the plural second rollers, which fluctuates a velocity of the second belt unit.

Image forming apparatus including first and second image forming devices and first and second belt units

An image forming apparatus includes a plurality of image carriers, an optical writing unit, a plurality of developing units, a transfer member, a transfer unit, an image sensor, and a control unit. In at least one embodiment, the image sensor is configured to sense a positional displacement detection pattern including visible images on the transfer member to detect a positional displacement between the visible images on each of the plurality of image carriers. The control unit is configured to execute a positional displacement correction control to calculate an amount of the positional displacement and determine respective target drive speeds of the plurality of drive sources. The control unit is also configured to control so that the positional displacement detection pattern is formed when the plurality of drive sources are driven at substantially identical speeds and the positional displacement detection pattern thus formed is sensed by the image sensor.

Image forming apparatus capable of effectively forming a quality color image

An image forming apparatus includes: image detectors to detect conditions of images, respectively, formed on a transfer member; sensors to detect rotational displacements of latent image carriers, respectively; and a controller to perform at least phase adjustment control and image-to-image displacement control before performing image forming operations on image carriers, respectively. Image-to-image displacement control includes adjusting image forming timing on the image carriers based upon conditions of a detection image (including images transferred from the image carrier) detected by the image detectors, respectively. Speed-variation detection control includes detecting a condition of a speed-variation detection image (including an image transferred from each of image carriers) via the image detectors, and determining speed variation of the image carriers, respectively, per one revolution based upon outputs of the image detectors and the sensors. Phase adjustment control includes determining phase adjustments for the image carriers, respectively, based on the corresponding speed-variations.

Image forming apparatus having enhanced controlling method for reducing deviation of superimposed images

An image forming apparatus, in which a program for carrying out an image forming method is provided, includes a transfer member to receive respective images formed on a plurality of image bearing members, an image detecting unit to detect the images conveyed on the transfer member, a paper length detecting unit to detect a length of a recording medium in a sheet travel direction, a counting unit to count the number of recording media and to change a count up value according to a detection result by the paper length detecting unit, and a control unit to control an image forming timing with respect to the image bearing members based on a detection timing of the image and to perform a positional deviation adjustment each time a counted value increases by a predetermined amount so as to reduce an amount of a positional deviation of the image.

Method, apparatus, and program for image forming capable of effectively adjusting positional deviation

An image forming apparatus to form an image on a recording medium, capable of reducing deterioration of image bearer, is disclosed. In one embodiment, the image forming apparatus includes an image bearer, a driver to move the image bearer, a image forming device to form a visible image on the image bearer, a contacting member to form a nip by contacting with the image bearer, and a controller to control the driver for driving stop with a distance shifted on a surface of the image bearer from a start of driving. An amount of the shifted distance is greater than a width of the nip and is not a divisional number of a peripheral length of the image bearer.

Growing community of inventors

Yokohama, Japan

Kouji Amanai