Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Mita Industrial Co., Ltd.

Toyotsune Inoue

Noriaki Ozawa

Takeshi Watanabe

Hiroyuki Ueda

Hiroatsu Tamai

Takatoshi Nishimura

Susumu Hiroshima

Takahisa Nakaue

Akihiro Watanabe

Masashi Fujishima

Yukihiro Mori

Shoichi Sakata

Naoto Miyakoshi

Yasuhiro Michishita

Yusuke Takano

Hiroshi Shimoyama

Takayuki Itakura

Eiji Nimura

Yoshitake Shimizu

Hirohisa Endou

Shingo Sakato

Kenshi Matsui

Kazuya Nagao

Takahiro Ishihara

Norio Horikami

Takashi Nishino

Naruo Yabe

Yasuko Takaori

Toshiro Okae

Takuya Kadota

An ink set includes an inkjet ink and a recording head filling liquid. The inkjet ink includes a pigment, a pigment coating resin, a first alkali metal ion, and water. The recording head filling liquid includes polyethylene glycol, a second alkali metal ion, a surfactant, and water. The polyethylene glycol has a mass average molecular weight of at least 180 and no greater than 800. A content ratio of the surfactant in the recording head filling liquid is greater than 0.00% by mass and no greater than 0.10% by mass. The first and second alkali metal ions each contain at least one of Li, Na, and K.

Ink set and recording head testing method

An inkjet recording apparatus includes memory, a processor, an image forming section, and a bending mechanism. The memory stores therein bending information in which a plurality of bending amounts corresponding to respective ejection amounts of an ink ejected from the image forming section are defined. The processor sets a bending amount of a sheet to be conveyed. The bending mechanism includes a roller and a belt that hold the sheet therebetween, and bends the sheet by moving a position of a center of the roller toward the belt based on the set bending amount. The processor calculates for each of areas of the sheet an amount of the ink ejected to the area, and sets the bending amount of the sheet based on the bending amounts corresponding to the calculated amounts of the ink ejected to the respective areas in the bending information.

Inkjet recording apparatus

An inkjet recording apparatus includes three or more recording heads. The recording heads contain different inks and eject the different inks sequentially on a recording medium. The different inks each contain a pigment and a polyhydric alcohol monobutyl ether. Of the different inks, an ink to be ejected first has the lowest pigment content ratio. Of the different inks, an ink to be ejected third and an ink to be subsequently ejected each have a pigment content ratio equal to or higher than that of a corresponding one of inks to be precedently ejected. Of the different inks, an ink to be ejected second and an ink to be subsequently ejected each have a polyhydric alcohol monobutyl ether content ratio higher than that of a corresponding one of inks to be precedently ejected.

An inkjet recording apparatus includes an image forming section, a heater, a first calculation section, storage, and a second calculation section. The image forming section ejects ink onto a sheet in which first to M-th regions are defined (M is an integer of at least 2). The heater heats an n-th region of the sheet using an n-th heat source (n is an integer of at least 1 and no greater than M). The storage stores therein temperature information indicating a first heating temperature for the n-th region. The second calculation section calculates a second heating temperature for the n-th region based on the temperature information and the ink ejection amount to the n-th region calculated by the first calculation section.

A de-curling device de-curls a sheet and includes an endless belt, a de-curling roller, a nip width adjusting mechanism, and a belt tension adjusting mechanism. The endless belt is looped around a pair of supporting rollers. The de-curling roller is provided between the pair of supporting rollers and has a first outer circumferential surface pressed against a second outer circumferential surface of the endless belt to form a nip portion at which the endless belt curves along the first outer circumferential surface, the de-curling roller being configured to de-curl the sheet passing through the nip portion. The nip width adjusting mechanism adjusts the nip width by moving the de-curling roller in a direction intersecting the second outer circumferential surface of the endless belt. The belt tension adjusting mechanism adjusts the tension of the endless belt according to the nip width adjusted by the nip width adjusting mechanism.

De-curling device and image forming apparatus including same

A controller checks ink quantity to be ejected to a specific area on a first side (specific area ink quantity) and determines an ink quantity ratio. The specific area is a strip-shaped area including a side edge on upstream side in a conveying direction of a paper sheet on the first side. When the ink quantity ratio is larger than a reference ink quantity ratio, the controller performs a black conversion process on pixels in a conversion target range. The conversion target range is a range corresponding to the specific area in the image data of the first side. The black conversion process is a process of converting a pixel to which three color inks, i.e. cyan, magenta, and yellow inks are to be ejected into a pixel to which only black ink is to be ejected.

Image forming apparatus and method for controlling image forming apparatus

An inkjet recording apparatus () includes an image forming section (), a decurler (), a changing section (), a first calculating section (), storage (), a second calculating section (), and a controller (). The image forming section () ejects ink onto a sheet (S). The decurler () bends the sheet (S). The changing section () changes a bending amount of the sheet (S). The first calculating section () calculates an ink ejection rate (&#x3b1;) to the sheet (S) for each of areas of the sheet (S). The storage () stores therein first bending information () indicating a first target bending amount (&#x3b2;) of a specific area of the sheet (S) corresponding to the ink ejection rate (&#x3b1;) to the specific area. The second calculating section () calculates a second target bending amount of each of the areas. The controller () controls the changing section () based on the second target bending amounts.

An inkjet recording apparatus includes an image forming section, a roller, a heat source, a calculator, a determination section, and a controller. The determination section determines to activate the heat source when an ink ejection amount calculated by the calculator is larger than a specific reference amount. When the determination section determines to activate the heat source, the controller activates the heat source. When temperature of the roller is equal to or higher than a specific temperature, the controller controls the image forming section to form the image on the sheet.

An inkjet recording apparatus includes three or more recording heads. The recording heads contain different inks and eject the different inks sequentially on a recording medium. The different inks each contain a pigment. Of the different inks, an ink to be ejected first has the lowest pigment content ratio. Of the different inks, an ink to be ejected third and an ink to be subsequently ejected each have a pigment content ratio equal to or higher than that of the pigment contained in a corresponding one of inks to be precedently ejected. Of the different inks, an ink to be ejected second and an ink to be subsequently ejected each have a lower viscosity at 25&#xb0; C. than a corresponding one of inks to be precedently ejected.

A decurling device includes a decurler. The decurler includes a first dryer roller, a second dryer roller, and a heat source. The heat source is disposed at the first dryer roller to heat the first dryer roller. The first dryer roller and the second dryer roller rotate while holding a sheet therebetween to convey the sheet.

Decurling device and inkjet recording apparatus

An inkjet recording apparatus includes an image forming section, a heater, a calculation section, storage, and a determination section. The image forming section ejects ink onto a sheet in which first to M-th regions are defined (M is an integer of at least 2). The heater includes first to M-th heat sources and heats an n-th region of the sheet using an n-th heat source (n is an integer of at least 1 and no greater than M). The calculation section calculates an ink ejection rate of ink to be ejected onto the n-th region. The storage stores therein heating information indicating whether it is necessary to heat the n-th region. The determination section determines whether or not to cause the n-th heat source to generate heat.

A decurling device includes a belt, a roller, and a heat source. The heat source heats either or both of the belt and the roller. The belt has a first holding surface extending in a rotational direction of the belt. The roller has a second holding surface extending in a rotational direction of the roller. The decurling device has either or both of a plurality of belt through holes penetrating the first holding surface and a plurality of through holes penetrating the second holding surface.

A decurling device includes a first conveyance path, a second conveyance path, a first switch, a decurler, and a controller. A sheet is conveyed along the first conveyance path or the second conveyance path. The first switch switches a route of conveyance of the sheet to the first conveyance path or the second conveyance path. The sheet has a first main surface and a second main surface. The decurler is located in the second conveyance path. The decurler corrects curl of the sheet. In a situation in which a weight per unit area of the sheet is smaller than a first threshold value, the controller controls the first switch such that the sheet is conveyed along the second conveyance path.

A developing unit has a voltage-applicator () to apply a developing bias voltage to a developing roller (). The voltage-applicator () applies the developing bias voltage for a first duration to apply an AC voltage having a rectangular waveform, and a second duration to stop applying the AC voltage. The AC voltage has a duty ratio of 50% or more in a direction for causing toner to develop an electrostatic latent image. The number of cycles of the AC voltage in the first duration is two or more, and the AC voltage has a voltage in a direction for pulling the toner back to the developing roller, just before transition to the second duration. The developing unit suppresses occurrence of image unevenness due to a fluctuation in developing gap. Thus, an image forming apparatus equipped with the developing unit forms a high-quality image while suppressing image unevenness.

Developing unit and image forming apparatus

A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.

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Osaka, Japan

Toyotsune Inoue