Canon Kabushiki Kaisha

Yuji Kamiya

Toru Katsumi

Jun Asai

Atsushi Takeda

Takahiro Nakase

Hiroaki Tsuchiya

Ryuji Kawano

Tetsuhiro Shibayama

An image forming apparatus including (a) a &#x3b3; conversion unit having a &#x3b3; conversion table &#x3b3;&#x3b1;of a first one Vcont&#x3b1; of a designation development contrast in a case that a development contrast correction amount &#x394;Vcontis a first value, and a &#x3b3; conversion table &#x3b3;&#x3b2;, different from the &#x3b3; conversion table &#x3b3;&#x3b1;, of a second one Vcont&#x3b2;, different from the first one Vcont&#x3b1;, of the designation development contrast in a case that the development contrast correction amount &#x394;Vcontis a second value different from the first value, and (b) an arithmetic operation unit for calculating a &#x3b3; conversion table &#x3b3;Nowof a third one VcontNow of the designation development contrast in a case that the development contrast correction amount &#x394;Vcontis a third value, based on a formula: &#x3b3;Now=&#x3b3;&#x3b1;+(&#x3b3;&#x3b2;&#x2212;&#x3b3;&#x3b1;)&#xd7;(Vcont&#x3b1;&#x2212;VcontNow/(Vcont&#x3b1;&#x2212;Vcont&#x3b2;), wherein the subscript i is a value of an output density signal in the &#x3b3; conversion table. The &#x3b3; conversion unit conducts the &#x3b3; conversion of the third one VcontNow of the designation development contrast, based on the &#x3b3; conversion table &#x3b3;Nowcalculated by the arithmetic operation unit.

Image forming apparatus and image forming method

The invention provides an image forming apparatus and an image forming method, capable of providing an image with little deterioration, even in case the image contrast has to be adjusted not for the purpose of image adjustment, such as for reducing the toner consumption amount or for preventing the leak in the charging device.

Image forming apparatus with gamma conversion means

An image forming apparatus having an image bearing member on which an electrostatic image is formed, a first developer carrying member carrying a developer thereon, and a second developer carrying member disposed downstream of the first developer carrying member with respect to the direction of movement of the image bearing member, and designed such that one and the same electrostatic image on the image bearing member is developed with the developer carried on these developer carrying members, has a developer consumption mode in which during the other time than ordinary image formation, the developer borne on the first and second developer carrying members is shifted to the image bearing member, and during this developer consumption mode, control is effected so that the amount of developer consumed from the second developer carrying member to the image bearing member may be greater than the amount of developer consumed from the first developer carrying member to the image bearing member.

Image forming apparatus with a developer consumption control feature

An image forming apparatus is provided with an image bearing member, a charging member with a discharge wire and a grid, and a first current supply controlling member, which controls a current supply to the discharge wire. Also provided are a second current supply controlling member, which controls a current supply to the grid, a potential setting member, which sets a potential value on the image bearing member to be charged by the charging member, and a first current supply condition selecting member, which selects a current control condition of the first current supply controlling member or the second current supply controlling member according to the set potential. In addition, a second current supply condition selecting member selects a current control condition for the other current supply controlling member based on the determined current control condition.

Image forming apparatus having means to control condition of current supply to discharge wire and grid of charging member

There is disclosed the following constitution in order to accurately perform image area separation judgment by one pixel unit of a read image at a high speed and to form an image in which character sharpness is compatible with photograph gradation without generating a false outline in the boundary of character and photograph areas. For this purpose, a first calculation unit calculates the sum of absolute values of differences of image signals between a predetermined pixel in a predetermined two-dimensional area including one noticeable pixel in the read image and the peripheral pixel of the predetermined one pixel in the predetermined two-dimensional area, a second calculation unit calculates the sum of calculation results with respect to the respective pixels in the predetermined two-dimensional area, a judgment unit judges whether the one noticeable pixel is the pixel in the photograph area or the pixel in the character area, and the image processing, and image formation method are changed with respect to the noticeable pixel based on the judgment result.

Image formation apparatus, image formation apparatus control method, and storage medium storing computer-readable program

In a case where minute dirt is lain between light source and an original, since the light source moves in case of the fixing original reading which is an original reading system of reading an original image by fixing the original, the dirt is momently lighted by the light source and influence by the dirt for the read image is appeared in sight by only a minute dot. However, in case of the shifting original reading of reading the original image by shifting the original, since the relationship between the light source and the dirt is in a fixed state, the light source is always to light the dirt and the influence by the dirt for the read image is appeared in sight by a line or a plane. Therefore, in the present invention, edge emphasis degree of edge emphasis processing for the read image data is varied in accordance with a fact that the original reading system is the fixing original reading or the shifting original reading. Accordingly, the influence by the dirt in the shifting original reading can be reduced.

Image processing method and image processing apparatus

A high quality image forming apparatus capable of outputting a quality image at a high speed is provided, with which no unevenness is generated on an image and a fog or a change in density is less likely to occur. An exposing unit is operated by an over-filled scanner method for exposure by a rotational polygon mirror that reflects lights on a surface narrower than an incident beam width, and forms an electrostatic latent image by back area exposure for exposing a non-image part.

Image forming apparatus with development controller

An image forming apparatus includes an image bearing member, an image forming unit for forming an image on the image bearing member and a detector for detecting the surface potential of the image bearing member, wherein a first image forming mode and a second image forming mode in which the image forming conditions of the image forming unit are different from each other can be selected, and further, the apparatus includes a controller for controlling the image forming conditions in the first and second image forming modes on the basis of the result detected by the detector for the first image forming mode.

Image forming apparatus

A fixing device includes a roller arranged to come into contact with a recording member bearing an unfixed image thereon so as to fix the unfixed image to the recording member, and a separation member arranged to come into contact with the roller so as to separate the recording member from the roller. A fore end of the separation member on a side for coming into contact with the roller is formed in a curved surface and intrudes into the roller. An amount of intrusion of the separation member into a surface of the roller is not less than a radius of a circle of curvature of the curved surface of the fore end of the separation member and not more than a diameter of the circle of curvature.

Fixing device having an intruding separation member

An electrophotographic apparatus has a detector, for detecting a surface potential on the photosensitive member, a determination unit, for employing the detection results obtained by the detector to determine an electrification amount for the electrification unit and an exposure control value for the exposure unit, for determining the electrification amount for the electrification unit, so that a dark portion potential on the photosensitive member is substantially a target dark portion potential selected from multiple target dark portion potentials, for determining a first exposure control value for the exposure unit, so that a light portion potential, which is based on the determined electrification amount and which is formed on the photosensitive member by the electrification unit and the exposure unit, is substantially a first target light portion potential, and for determining, in accordance with the first exposure control value and the selected target dark portion potential, a second exposure control value for the exposure unit, so that a light portion potential on the electrostatic image is substantially a second target light portion potential.

Electrophotographic apparatus with exposure control for multiple target light portion potentials

An image forming apparatus includes of an image bearing member, an image forming unit for forming a toner image onto the image bearing member, a transfer charging unit for transferring the toner image from the image bearing member to a transfer material at a transfer position, a guide member for guiding the transfer material to the transfer position, a sensor for detecting an ambient environment of the image forming apparatus, and a switch for switching whether the guide member is connected to a constant voltage element or is connected to the ground in accordance with a detection result of the sensor.

Image forming apparatus featuring an environmentally responsive voltage

An image forming apparatus comprises a plurality of decks for accommodating sheets, a feeder for feeding sheets from said decks, an image forming unit for forming an image on a sheet fed by said feeder, a detector for detecting thicknesses or colors of the sheets accommodated in said decks, an input unit for designating a desired thickness or color of the sheet, and a control unit for controlling said feed means to feed the sheet of the desired thickness or color from said decks.

Sheet transport apparatus for detecting a color of a document

A detector for detecting status quantities in processes of an image forming apparatus and a correction mechanism for changing parameters are connected to a controller. By virtue of this arrangement, the amount of current associated with a primary charging device in a latent-image process, the surface potential of a photoreceptor drum and a voltage correction coefficient are fed into the controller as status quantities. By using the entered status quantities as well as membership functions and fuzzy rules that have been stored in an internal memory of the controller, the controller executes fuzzy reasoning and outputs a signal indicating the failure rate or rate of erroneous setting of each processing element.

Growing community of inventors

Abiko, Japan

Yuji Kamiya