Abstract: An image processing apparatus includes a storage and processing circuitry. The storage is configured to store a dither table in which a plurality of dither patterns are recorded, each of the dither patterns being formed with a halftone dot screen in which an output area ratio that is a proportion of void halftone dots per unit area corresponds to any one of gradation values of image data. The processing circuitry is configured to read a gradation value for each region in image data input for each toner color, decide a dither pattern to be applied to the read gradation value, read out the decided dither pattern from the dither table, and perform dither processing of applying the read dither pattern to the region in the image data.

Abstract: An image processing apparatus includes a storage and processing circuitry. The storage is configured to store a dither table in which a plurality of dither patterns are recorded, each of the dither patterns being formed with a halftone dot screen in which an output area ratio that is a proportion of void halftone dots per unit area corresponds to any one of gradation values of image data. The processing circuitry is configured to read a gradation value for each region in image data input for each toner color, decide a dither pattern to be applied to the read gradation value, read out the decided dither pattern from the dither table, and perform dither processing of applying the read dither pattern to the region in the image data.

Abstract: An image processing apparatus includes: an image determining unit configured to determine a gradation value for each predetermined range in input image data; and a screen generator configured to arrange dot images around a plurality of growth centers in a halftone dot screen to form respective dot blocks if an input area rate indicating a ratio of black to white in dot images at the gradation value is smaller than a value at which an image defect occurs, and form bridges to connect adjacent dot blocks during a smallest gradation number if distances between the adjacent dot blocks decrease to a predetermined value or less along with growth of the dot blocks, to form a void halftone dot image.

Abstract: An image processing apparatus stores a first dither pattern group that includes dither patterns each corresponding to a gradation value in a first range and formed by line screens in which widths of lines are increased with an increase in the gradation value, a second dither pattern group that includes dither patterns each corresponding to a gradation value in a second range higher than the gradation value in the first range, and formed by void dot screens in which number of dots is increased and void regions surrounded by the dots are decreased with an increase in the gradation value, and a third dither pattern group that includes dither patterns for switching from the line screen to the void dot screen, switching to the void dot screen being completed before a first reference gradation value at which an image defect occurs for received image data is reached.

Abstract: An image processing apparatus includes: an image determining unit configured to determine a gradation value for each predetermined range in input image data; and a screen generator configured to arrange dot images around a plurality of growth centers in a halftone dot screen to form respective dot blocks if an input area rate indicating a ratio of black to white in dot images at the gradation value is smaller than a value at which an image defect occurs, and form bridges to connect adjacent dot blocks during a smallest gradation number if distances between the adjacent dot blocks decrease to a predetermined value or less along with growth of the dot blocks, to form a void halftone dot image.

Abstract: An aspect of the invention provides an image forming apparatus storing first, second, and third dither pattern groups. The first group contains a plurality of line screens, each associated with one of gray levels in a first range, varying such that as the gray level increases, the line width increases. The second group contains a plurality of void-dot screens, each associated with one of gray levels higher than those in the first range, varying such that as the gray level increases, dots increase to reduce void portions surrounded by the dots. The third group contains, for switching from the line screen to the void-dot screen, a plurality of dither patterns varying such that as the gray level increases from a reference gray level, adjacent lines are connected at joint portions tapered toward tip ends in a manner that a position that gradually advances from the tip ends to basal ends.

Abstract: An image processing apparatus stores a first dither pattern group that includes dither patterns each corresponding to a gradation value in a first range and formed by line screens in which widths of lines are increased with an increase in the gradation value, a second dither pattern group that includes dither patterns each corresponding to a gradation value in a second range higher than the gradation value in the first range, and formed by void dot screens in which number of dots is increased and void regions surrounded by the dots are decreased with an increase in the gradation value, and a third dither pattern group that includes dither patterns for switching from the line screen to the void dot screen, switching to the void dot screen being completed before a first reference gradation value at which an image defect occurs for received image data is reached.

Abstract: An aspect of the invention provides an image forming apparatus storing first, second, and third dither pattern groups. The first group contains a plurality of line screens, each associated with one of gray levels in a first range, varying such that as the gray level increases, the line width increases. The second group contains a plurality of void-dot screens, each associated with one of gray levels higher than those in the first range, varying such that as the gray level increases, dots increase to reduce void portions surrounded by the dots. The third group contains, for switching from the line screen to the void-dot screen, a plurality of dither patterns varying such that as the gray level increases from a reference gray level, adjacent lines are connected at joint portions tapered toward tip ends in a manner that a position that gradually advances from the tip ends to basal ends.

Abstract: An electrophotographic image output device includes an image processor to receive input image data, and a line screen to represent halftone images and have multiple screen angles respectively allocated to different colors including yellow, magenta, and cyan. The line screen satisfies requirements of (A) a predetermined difference is secured between adjacent two of the multiple screen angles; (B) zero is not allocated to any of the multiple screen angles; and (C) among the multiple screen angles determined by the requirements (A) and (B), a screen angle closest to 90 degrees is allocated to yellow among yellow, magenta, and cyan.

Abstract: An electrophotographic image output device includes an image processor to receive input image data, and a line screen to represent halftone images and have multiple screen angles respectively allocated to different colors including yellow, magenta, and cyan. The line screen satisfies requirements of (A) a predetermined difference is secured between adjacent two of the multiple screen angles; (B) zero is not allocated to any of the multiple screen angles; and (C) among the multiple screen angles determined by the requirements (A) and (B), a screen angle closest to 90 degrees is allocated to yellow among yellow, magenta, and cyan.

Abstract: An image forming method and apparatus capable of implementing accurately and constantly an improved conversion of the amount of toner adhesion over the entire range of the amount of adhesion.

Abstract: An image forming method and apparatus capable of implementing accurately and constantly an improved conversion of the amount of toner adhesion over the entire range of the amount of adhesion.

Abstract: An image transferring apparatus is provided which holds a print sheet in a nip between an image carrier and a transfer roller and supplies the current to the transfer roller to transfer a toner image formed on the image carrier to the print medium. The apparatus has conductive brushes disposed in contact with ends. of the transfer roller to form a bypass circuit. The bypass circuit is connected to ground through a resistor and introduce the part of the current supplied to the transfer roller in an image transferring operation, thereby avoiding formation of any print defects such as discharge-caused marks or toner stops.

Abstract: An electrophotographic recording apparatus includes a photosensitive drum on which an electrostatic latent image can be written, a developing device for developing the latent image of a charged visible image with a one-component developer, and a transferring device for electrostatically transferring the charged visible image from the drum to a sheet or paper. The developing device has a conductive foam rubber roller for entraining the developer to form a developer layer therearound and for bringing the layer to the drum for the development of the latent image, a conductive blade resiliently engaged with the foam rubber roller for uniformly regulating a thickness of the developer, and an electric source for applying electric energy to the blade to electrically charge the developer layer by a charge-injection effect.

Abstract: A blade controls a layer thickness of the developer and/or triboelectrically charges the developer on a surface of the developing roller in an electrographic imaging device. The blade is a longitudinally extended member made by punching a thin resilient plate of metal in a press mold, and a tip portion thereof has a curved tail part having a smooth surface and a gradually reduced thickness formed as a shear drop upon punching.

Abstract: An electrophotographic image forming apparatus includes an electrostatic latent image carrying body, an electrifying unit for electrifying the image carrying body, a light irradiating unit to form an electrostatic latent image in accordance to image information, a developing unit for discharging toner to the image carrying body to develop the latent image, a transfer unit for transferring the toner image to a recording sheet, and a cleaner for removing residual toner on the image carrying body. The toner removed from the image carrying body is recirculated to the developer receiving box. An additional toner image is formed on a position other than a first position where the electrostatic latent image is formed in accordance with the image information. The toner is removed by the cleaner without being transferred to the recording sheet and recirculated from the image carrying body to the developer receiving box.

Abstract: An electrostatic latent image formed on a photosensitive drum is electrostatically developed with a non-magnetic type developer, and is electrostatically transferred from the drum to a paper. The developer is composed of a toner component and a resin powder component, one component of which has a polarity opposite to that of an electric charge of the other component generated by triboelectrification therebetween. In the developing process, a conductive foam rubber developing roller is used, which includes a conductive tubular foam rubber roller element, and a metal shaft inserted into a central bore thereof. The roller element has an outer thicker portion including a conductive filler dispersed therein, and an inner solid skin layer defining the central bore thereof and exhibiting an electrical resistivity considerably higher than that of the thicker portion for lack of conductive filler. Nevertheless, a sufficient electrical contact is established between the roller element and the shaft.

Abstract: A developing apparatus provided with a developer holding container (16a) which holds a mono-component developer and an electroconductive elastic development roller (16b ) which is provided inside the developer holding container in a manner enabling it to be driven to rotate. The electroconductive elastic development roller is disposed so that a portion of it is exposed from the developer holding container and contacts the image carrier. The mono-component developer is made to deposit on its rotating surface and form a mono-component developer layer. By the rotation of this, the developer is transferred to the region of contact with the image carrier. The developing apparatus includes an electroconductive leaf spring member (16c) for regulating the thickness of the mono-component developer layer of the electroconductive elastic development roller.

Abstract: An image forming device supplies developing agent to developing portion for developing a latent image in devices such as those using electrophotography. A developing agent supplying body is formed of soft synthetic foam resin material imparted with conductivity, and imparted with physical properties such that a property of F, defined by F=S.multidot..rho./H, is between 72 and 114, where H is hardness, .rho. is density, and S is cell count of bubbles. Alternatively, the developing agent supplying body may be configured such that a moving speed of a developing agent supplying body at a contact surface is 1.4 to 1.7 times that of a developing agent transporting body. Both the above configurations ensure that an optimal amount of developing agent is supplied to the developing agent transporting body for transporting developing agent to the developing portion, thus allowing for good quality printing to be obtained.

Abstract: A toner image transferring device has a roller formed of a conductive rubber foam material having a resistivity of more than 10.sup.7 .OMEGA.cm. In a toner image transferring process, a constant current is applied to the roller, whereby a charged toner image can be transferred to a sheet or paper at a desired toner transfer efficiency regardless of a size of the paper or sheet. To remove a toner pollution of the roller, a constant voltage having a polarity opposite to that of the charged toner is applied to the roller. The roller is constituted such that pore openings appear over a surface of the roller, whereby a residual part of a toner polluting the roller will not leave a stain on a rear surface of the sheet or paper.