Minolta Company, Ltd.

Konica Minolta Business Technologies, Inc.

Kentaro Katori

Katsuyuki Hirata

Yukihiko Okuno

Yoshinobu Hada

Masahiro Kouzaki

Hironobu Nakata

Masaki Tanaka

Kuniya Matsuura

Akira Hirota

Yoshihiko Hirota

Masahiko Matsuura

Toru Hayase

Hiroaki Umemoto

Mineyuki Sako

Suguru Hamamichi

Noritoshi Hagimoto

Naotoshi Kawai

Yuusuke Okuno

Toshifumi Watanabe

Shinichi Yoshimoto

Kenichi Sawada

Atsushi Kawai

Junji Nishigaki

Tetsuya Sakai

Naoki Toyoshi

Tsutomu Yamazaki

Kanji Nakayama

Shinichi Takemoto

Tomoji Tanaka

Yoshihiro Shojo

Tomo Kitada

Hiromasa Ueno

Fujio Hashimoto, Legal Representative

Nobue Hashimoto, Legal Representative

Tomoki Wada

Developing bias is set as follows. An electric field intensity between a developing roller and a photoconductor is set to cause normally-charged toner to fly in an image area and not to cause the toner to fly in a background area. Thus, the normally-charged toner does not fly in the background area. The normally-charged toner caused to fly is therefore unlikely to flick low-charged toner and oppositely-charged toner. The low-charged toner and the oppositely-charged toner will not adhere to the background area and cause image fogging. Accordingly, an image forming apparatus can be provided to prevent the low-charged toner and the oppositely-charged toner from adhering to the background area of an electrostatic latent image on the photoconductor and to avoid the occurrence of image fogging in the background area on a printed material.

Image forming apparatus and image forming method for adjusting developing bias

A potential difference between the photoreceptor and the development roller is set at a value at which the normally charged toner on the development roller can be flown toward the photoreceptor in the development phase at the time of compulsorily consuming the toner, and this potential difference is set at a value at which the flown normally charged toner can be returned to the development roller in the recovery phase.

Image forming apparatus with toner discharge method

A color printer including, a conductive brush roller to contact a photosensitive drum at a position downstream of a transferring apparatus and upstream of a charging apparatus, wherein at least part of residual toner is collected after temporarily transferring on the photosensitive drum, and the collected toner is expelled onto the photosensitive drum, a charge electrode facing the brush roller at a position other than the contact position of the photosensitive drum and the brush roller, and a power source to apply voltage to the charge electrode, wherein the polarity of the voltage applied from the power source to the charge electrode with respect to the average voltage of the surface of the photosensitive drum after transferring is the same as a charging polarity of the toner at developing.

Image forming apparatus, charge controlling apparatus, and image forming method

An image forming apparatus using an exposure unit of a solid-scanning type such as an LED head, reads out linear distortion correction data of an LED unit, then, calculates an amount of correcting color deviation based on the read-out data, and after that, carries out address control for color deviation correction memory. Based on this control, the apparatus creates a reference resist patterns, calculates an amount of correcting the color deviation, and writes the calculated amount in the color deviation correction memory. After that, the apparatus reads out the linear distortion correction data, and adds the amount of correcting the color deviation that is determined by sensors, and the amount of the color correction based on the linear distortion correction data, thereby carries out address controls for the color deviation correction memory. This constitution allows correcting linear distortion of the exposure unit itself with ease and accuracy, and correcting positional deviation of the exposure unit occurring during product assembly and deviation in a linear arrangement of an LED head with accuracy.

Image forming apparatus having a function for correcting color deviation and the like

It is intended to provide an image forming apparatus capable of conducting charge adjustment of post-transfer residual toner appropriately by securing a contact area of a temporarily-collecting member and an electrode, without applying excessive deformation load to the temporarily-collecting member. There are arranged a brush roller for temporarily collecting post-transfer residual toner, and an electrode of which inwardly-curved face being in contact with the brush roller in a toner charge apparatus. Thereby, charged-in-opposite-polarity toner, out of post-transfer residual toner, is collected by the brush roller, polarity of the toner is reversed to original polarity, and then, returned to a photosensitive drum. The inner face of the electrode, i.e., a contact face of the electrode and the brush roller is formed in an inwardly-curved face. Thereby, a large contact area and light pushing force of the electrode to the brush roller can go together.

Image forming apparatus

It is intended to provide a developing apparatus, an image forming apparatus and developing method capable of managing both decrease of load on apparatuses and improvement of image quality in case development of an image is made by applying contact developing and AC developing. For that intention, voltage at a portion between a development member and an image carrier is defined oscillating voltage, and in case negative polarity toner is used, relations of peak voltage Vof oscillating voltage, background portion voltage VH (negative) and visible section voltage VL (negative, an absolute value of it is smaller than that of VH) are set as indicated below.&#x2212;500V&#x2266;1350V&#x2212;200V&#x2266;150VOn the above conditions, peak voltage Vis set as indicated below.&#x2212;150V&#x2266;2&#x2266;&#x2212;70V2500V.

Developing apparatus, image forming apparatus, and developing method

An image forming apparatus has a charging member opposed to an outer circumferential surface of a rotating object to be charged. The image forming apparatus has a voltage applying section for applying a pulsating voltage Vsp between the charging member and the object to be charged. The pulsating voltage Vsp is obtained by superimposing a voltage component of a direct current on a voltage component that periodically changes. The image forming apparatus is made to satisfy a relation of Vpp&#x2266;|Vth|, where Vpp is a peak-to-peak voltage value of the pulsating voltage Vsp and Vth is a charging start voltage value of the object to be charged. The relation prevents opposite charge from being imparted to residual toner on the object to be charged.

Charging device and image forming apparatus provided therewith

An image forming device capable of providing an image of excellent quality without unevenness of density. According to the image forming device, a controller measures light quantity for each light emitting element of the exposing device as to the pattern where only one of the light emitting elements is turned on, and as to the pattern where all the light emitting elements are turned on. Based on the data about the measured light quantity, a change rate in the light quantity distribution of the exposing device is calculated. Based on the data about the measured light quantity and the change rate in the light quantity distribution calculated, correction value for each of the light emitting elements of the exposing device is determined.

Light quantity correction method for exposing device, and image forming device

A method of and apparatus for forming an image adapted to apply an error diffusion method to an input image data having N gradations so as to convert it into an output image data having M gradations, where M<N. Correspondence between N-stage gradation levels of the input image data and M-stage gradation levels of the output image data can be varied. This apparatus for forming an image has control means for setting the aforesaid correspondence in accordance with data obtained from the measurement of the image densities of a printout having specific gradation levels which do not give rise to errors in the aforesaid conversion.

Method of and apparatus for forming an image

An image forming apparatus for forming an image with few defects even when making a copy from a copied image. When forming an image, a standard pattern is formed outside the image forming area in accordance with standard pattern data for color correction. When reading the image together with the standard pattern formed above, the color correction conditions for the image data are modified in accordance with the comparison result between the read standard pattern data and the standard pattern data for color correction. Copying is then performed on a copying paper.

Image forming apparatus which excels in reproducibility of colors, fine lines and gradations even in a copy made from a copied image

An apparatus and method for processing an image which are capable of producing a printed image satisfying both resolution and reproducibility of gradation. This method admits as an input the RGB data of the size of one pixel and converts this input into lightness data and density data. When a target pixel is determined to correspond to a non-edge portion, the method performs a computation for finding the remainder,of X/,and the remainder m of Y/,from the coordinates (X,Y) of the target pixel thereby deciding which of the total of nine pixels of a non-edge grade dither pattern is to be extracted, and allocates the position d(l,m) to the extracted pixel. On the other hand, when the target pixel is determined to correspond to an edge portion, an edge grade dither pattern corresponding to the density of the target pixel is allocated directly to the target pixel. The processing of conversion into the non-edge grade dither pattern d(l,m) or the processing of conversion into the edge grade dither patter which is performed as described above is carried out on all the pixels which have been read, depending on the determination of whether the target pixel corresponds to the non-edge portion or the edge portion, and the converted data obtained consequently is emitted.

Apparatus and method for processing image

In a copying machine, a printer control unit calculates .gamma. correction data according to a grid potential Vg and a development bias potential Vb which are image forming parameters, and a calculation coefficient. The printer control unit reads reflectance data of a copied test pattern in a test pattern read out mode to correct the calculation coefficient for the calculation of .gamma. correction data according to the read out data. Thus, .gamma. correction at always the optimum and accurate level can be carried out without usage of a memory of a large capacity.

Image formation apparatus that allows correction of .gamma. correction

Pixel data comprising density data of R, G, and B obtained by reading an original with a CCD image sensor are subjected to shading correction by a shading correction unit, and then converted into color region signals H*, V, and C* in the Munsell color space by a first converter. According to the variations of V, a region discriminator determines whether each pixel data belongs to an edge portion of the original image or whether it belongs to a uniform density region of the original image. A noise removing unit performs noise removal by performing smoothing on color region signals H*, V, and C* of the pixel data which have been determined to belong to uniform density regions. A second converter converts the noise-removed color region signals into pixel data of R, G, and B.

Image forming apparatus having a noise removing unit

An image forming apparatus which forms an image according to image data made up of pixel data on colors of pixel constituting an original image, characterized by comprising a color region discriminator for determining to which color region each pixel data belongs, an image region discriminator for determining whether the pixel data belongs to a uniform density region or whether it belongs to an edge portion, a corrective condition deciding unit for determining MTF corrective conditions for the image data of each color region depending on the discrimination results of both the color region discriminator and the image region discriminator, and an MTF correction unit for performing MTF corrections on the image data according to the MTF corrective conditions determined by the corrective condition deciding unit.

Image forming apparatus having an MTF correction unit

The individual pattern of each color of the standard pattern is printed on a copy being made, and when the copy is read by a scanner, the image data of the standard pattern are converted into color region signals in a uniform color space by an HVC converter and a C.multidot.H operation unit. In the case where the saturation of the image data has become lower than the standard saturation of the color region, saturation corrective coefficients are determined by a saturation corrective coefficient calculation unit. After the saturation coefficients have been determined for each color of the standard pattern, the image data of the original are read out, and the saturation corrective coefficients for the color region of the image data are used for saturation correction by a saturation correction processing unit. The image data which have been subjected to the saturation correction are reversely converted into the image data of each color by a reverse HVC converter. According to the reversely converted image data, an image is formed on a copying paper.

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Kentaro Katori