Ricoh Company, Ltd.

Masami Kadonaga

Takuro Sekiya

Takashi Kimura

Eiko Suzuki

Shuji Motomura

Masanori Horike

Yoshio Watanabe

Hiromichi Komai

Tomoaki Nakano

Takayuki Yamaguchi

Toshio Inada

Mitsuru Shingyouchi

Toshitaka Hirata

Tatsuya Niimi

Katsuo Sakai

Osamu Naruse

Hiroyuki Sugimoto

Takahiko Tokumasu

Osamu Endo

Minoru Ameyama

Syuzo Matsumoto

Kouji Izumi

Kenichi Ichikawa

The present invention relates to an image forming apparatus, an image forming process and a process cartridge, in which the image quality and the durability of the photoconductor may be enhanced, images may be formed stably even after the repeated usages, and higher quality and higher stability of images may be established due to the superimposed alternating voltage as well as decrease of the charging hazard on the photoconductor. Specifically, the image forming apparatus according to the present invention comprises a photoconductor, latent electrostatic image forming unit, developing unit a transferring unit, and fixing unit, wherein the charging member is of roller shape disposed proximate to the photoconductor, the photoconductor is charged at the charging nip portion formed between the photoconductor and the charging member, in a condition that satisfies the following Equation:4.4&#xd7;10&#x2266;[(Number of Charged Particles)&#xf7;(Circumferential length of the photoconductor)]&#x2266;17.7&#xd7;10

Image forming apparatus, image forming process, and process cartridge

A charging apparatus for use in an image forming apparatus includes a charge roller configured to adjoin to a photoconductive member to provide a charge to a surface of the photoconductive member. The charge roller includes a plurality of roller layers. One of the plurality of roller layers has a resistance ratio with which a roller surface potential is raised by a charge movement. In this case, the resistance ratio has a value such that a time period in which a charge moves within the one of the plurality of roller layers is sufficiently smaller than a time period in which an arbitrary point of the surface of the charge roller moves across a discharge region formed between the charge roller and the photoconductive member.

Apparatus for image forming and charging capable of effectively maintaining a charge potential

An image forming apparatus and method thereof for reducing a transfer charge in a portion where an image carrier and a transfer body contact each other, and obviating the deterioration of images ascribable to Paschen discharge apt to occur at the end of the contact portion. A relationship exists between an image transfer nip, a discharge electrode and a transfer electrode of the image forming apparatus.

Image forming apparatus and method configured to reduce a transfer

A method of forming a powder image on a recording medium and an apparatus therefor are disclosed. The apparatus includes a toner carrier for carrying powdery toner in a layer or layers thereon, a counter electrode, and a flight control member having independent or continuous extremely small holes and a plurality of control electrodes for controlling the passage of toner through the holes. A voltage is applied to the control electrodes in accordance with an image signal in order to cause the toner to fly from the toner carrier toward the counter electrode via the holes. The toner deposits on the recording medium intervening between the flight control member and the counter electrode, forming an image on the recording medium. The method and apparatus are capable of increasing a recording speed, recording an image even on a paper in a humid environment or on a conductor, simplifying circuitry for driving control electrodes included in the flight control member, promoting the effective use of drivers during image formation, causing only a part of toner for forming an image to fly, and reducing the cost.

Method and apparatus for forming a powder image

A liquid jet recording head includes a liquid path member having a plurality of liquid flow paths, each of the liquid flow paths being filled with a recording liquid, an orifice being formed at an end of each of the liquid flow paths, and a heater base member having a plurality of heater members and a plurality of radiator members. The heater base member is connected to the liquid path member, each of the heater members having a heater portion, the heater portion generating heat in accordance with a power supplied to it. Each of the radiator members is thermally coupled to the heater portion of one of the heater members so that the amount of heat transmitted from the heater portion to the recording liquid on the heater portion changes in a predetermined direction. When a power is supplied to the heater portion, a bubble is generated in the recording liquid and located at an area on the heater portion, the area having a size corresponding to the power supplied to the heater portion, the bubble causing a recording liquid droplet to be jetted from the orifice.

Liquid jet recording head having improved radiator member

An ink jet recording apparatus is provided with an ink jet recording head which includes at least one nozzle for ejecting ink, a heating layer, and a ground electrode and a plurality of control electrodes electrically connected to the heating layer, and a thermal energy action part, formed in the heating layer in correspondence with the nozzle, for heating the ink and causing a state transition so as to eject the ink from the nozzle when a voltage is applied across at least one pair of the ground electrode and the control electrode. The ground electrode electrically connects to the heating layer within a region of the thermal energy action part, and the control electrodes electrically connects to the heating layer outside the region of the thermal energy action part.

Ink jet recording method and apparatus having drop size control by using

A liquid jet recording head includes a base member, a liquid layer maintained on the base member and a plurality of heater elements, arranged in a line on the base member, for supplying energy to liquid adjacent thereto, the energy operation portions being put under the liquid layer. A method for making a liquid drop fly from the liquid jet recording head onto a recording sheet so that a dot image is formed on the recording sheet includes steps of (a) generating a bubble in the liquid to which the energy is supplied by each of energy operation portions in accordance with image data; (b) making the bubble grow up until a predetermined size of the bubble is obtained; (c) contracting the bubble under a condition where each of the energy portions supplies no energy to the liquid in which the bubble is formed; and (d) making the bubble disappear into the liquid.

Method and apparatus for making liquid drop fly to form image by

An ink jet recording head assembly includes: a base member having a plurality of enclosures, a top of each of the enclosures having an opening; a mechanism for supplying ink to each of the enclosures via the opening at the top thereof and for maintaining the ink at a predetermined depth; and a heater element which is provided in each of the enclosures under the ink supplied via the opening, the heater element heating the ink in each of the enclosures so that a bubble is generated in the ink; wherein an ink drop is jetted from a surface of the ink due to the bubble generated in the ink.

Ink jet recording head assembly

An ink jet printing head driving method includes steps of: applying a voltage falling edge of a first pulse signal to cause a piezoelectric element to contract so that a capacity of a liquid passage is increased so as to supply ink to the liquid passage; applying a voltage rising edge of the first pulse signal to cause the piezoelectric element to expand so that the capacity of the liquid passage is decreased, for discharging an ink droplet through a discharge port, the first pulse signal having a first pulse width and a first peak voltage amplitude; and applying a voltage rising edge of a second pulse signal to the piezoelectric element after a predetermined delay time has elapsed since application of the first pulse signal for discharging the ink droplet, a pulse width of the second pulse signal being smaller than the first pulse width, and a peak voltage amplitude of the second pulse signal being equal to the first peak voltage amplitude.

Method of driving ink jet printing head

An ink jet head used for pulsed droplet ink jet printer uses a grooved piezo-electric element. The piezo-electric element includes a plurality of grooves, diaphrams and actuators. The actuator and two grooves at both sides of the actuator, filled with stuffing material, covers a corresponding one of passages. Therefore, even if the stuffing material moves when the actuator is energized, an interference problem does not occur. Consequently, the flexure force of each actuator can transmit to the corresponding passage to jet ink in the passage via a nozzle.

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Yokohama, Japan

Masami Kadonaga