Canon Kabushiki Kaisha

Nobuyuki Ito

Hiroaki Tsuchiya

Takeshi Ikeda

Yukio Nagase

Yuji Sakemi

Yasukazu Ayaki

Isami Itoh

Tomohito Ishida

Yoshiro Tomikawa

Kenichiro Waki

Keishi Ohsawa

Takehiro Takano

Hiroyuki Suzuki

Jun Hirabayashi

Masataka Kawahara

Yasunori Chigono

Harumi Ishiyama

Masanori Miyata

Seiji Mashimo

Mamoru Tanaka

Toru Katsumi

Tadashi Furuya

Keishi Osawa

The image forming apparatus has an image forming portion capable of forming an image on a transferring medium by the use of a hypochromatic toner and a hyperchromatic toner of substantially the same color. The image forming portion is provided with a developing device for developing with the hypochromatic toner and the hyperchromatic toner, wherein, in an image area in which the hyperchromatic toner and the hypochromatic toner are mixedly present, the recording rate of the hyperchromatic toner is 1/16, the minimum size Wmini of a toner image of the hyperchromatic toner is 50 &#x3bc;m or less on the transferring medium. Thereby, it is achieved to reduce graininess.

Image forming apparatus using hypochromatic toner and hyperchromatic toner

In an electrophotographic image recording apparatus apparatus including a photoconductive image bearing member, a charging apparatus for uniformly charging the image bearing member, an exposure apparatus for effecting an imagewise exposure on a surface of the image bearing member after charging thereby forming an electrostatic latent image, a development apparatus for adhering a toner onto the electrostatic latent image thereby forming a toner image, and a transfer member for transferring the formed toner image onto a final support member such as plain paper, in case of forming an image with a hyperchromic toner and a hypochromic toner of a substantially same hue, image formation is executed with a writing resolution for the hypochromic toner larger than a writing resolution for the hyperchromic toner. Thus drawbacks of streak generation by a screen used for the hypochromic toner and a difficulty in obtaining a photographic texture can be resolved.

Electrophotographic image recording apparatus and method therefore

The image forming apparatus includes an image forming unit capable of forming an image with a hypochromic toner and a hyperchromic toner of a substantially same hue, a first toner containing portion containing the hypochromic toner, a second toner containing portion containing the hyperchromic toner, and a density detecting unit which detects a density of an image formed with the hypochromic toner and the hyperchromic toner. Thus an image can be formed with the hypochromic toner and the hyperchromic toner of a substantially same hue.

Image forming apparatus with density detecting means

A transfer sheet has a base layer and a specific surface layer. In a plot graph with load P (mN) as ordinate and the square of indentation depth A (&mgr;m) as abscissa, plotted when the tip of a diamond triangular pyramid penetrator having a dihedral angle of 80&deg; is pressed in on the side of the surface layer, the plot graph has a first flexing point that appears first, a first region extending from the first flexing point to zero and a second-and-further region subsequent to the first flexing point, and a gradient H of the graph in the first region is 0.09 mN/&mgr;m or smaller. Also disclosed are image-forming methods making use of such a transfer sheet. The transfer sheet has a superior effect of keeping dot toner images from scattering at the time of transfer. The base layer is paper made from pulp.

Transfer sheet and image-forming method

An image forming apparatus in which an image forming device has developing device for developing an electrostatic image formed on an image bearing member. The developing device has a first developing section for developing use of a first cyan toner, a second developing section for developing by use of a first magenta toner, a third developing section for developing by use of a yellow toner, a fourth developing section for developing by use of a second cyan toner that is lighter than the first cyan toner, and a fifth developing section for developing by use of a second magenta toner that is lighter than the first magenta toner. A sixth developing section is provided for developing by use of a black toner. A first rotator supports the first, second, third, fourth, fifth and sixth developing devices, and a second rotator supports the fourth and fifth developing devices.

Image forming apparatus and image forming method using color toner

A transfer device including a transfer electrode to which a voltage of a polarity opposite to that of a charged toner is applied, and an insulating support member which makes pressure contact with the image bearing body and supports the transfer electrode in a manner such that the transfer electrode is out of contact with the image bearing body and in contact with a copy sheet.

Transfer device employing a transfer electrode in the vicinity of an

An image forming apparatus includes an image bearing member; a charger for charging the image bearing member, the charger including a magnetic brush including magnetic particles contacted to the image bearing member; a developing device for developing an electrostatic image on the image bearing member, wherein the developing device includes a developer carrying member which is press-contacted to the image bearing member, and is movable in a direction opposite from a movement direction of the image bearing member at a portion where they are press-contacted to each other.

Image forming apparatus

An image forming apparatus includes a movable image bearing member; an electrostatic image forming device for forming an electrostatic image on the image bearing member, the electrostatic image forming device including a charging member, contactable to the image bearing member, for charging the image bearing member; developing device for developing the electrostatic image with toner to form a toner image on the image bearing member; a transfer device for transferring the toner image onto the transfer material from the image bearing member, wherein the developing device is capable of cleaning the image bearing member to remove residual toner from the image bearing member, without provision of cleaning device for removing the residual toner from the image bearing member at a position upstream of the charging member and downstream of the transfer device with respect to a moving direction of the image bearing member; and a charge application device, provided upstream of the charging member and downstream of the transfer device with respect to the movement direction, for charging the residual toner on the image bearing member to a polarity opposite from charging polarity of the charging member.

Cleanerless image forming apparatus

An image forming apparatus includes an image bearing device, a charger contactable to the image bearing device for effecting contact charging of the image bearing device, the charger being supplied with a voltage having a DC component and an AC component, and the charger being provided with an electrode for receiving the voltage; wherein the following is satisfied: when an electric field formed between the image bearing device and the electrode is not more than .vertline.E/d.sub.SD .vertline. (V/m), a resistance of the charger per unit area of contact between the image bearing device and the charger is larger than

Contact charger for charging a photosensitive member

An image forming method and apparatus which forms an image by using PWM to properly reproduce tones at a low density in the image formation, and attain a high-quality image without reducing the resolution in the dot formation corresponding to a high density value. A color laser beam printer using the PWM to which the present invention is applied forms a latent image onto a photosensitive drum by the laser beam irradiated from a semiconductor laser. The waveform of a chopped wave signal used in the PWM is set to be unique with respect to each color component, and be asymmetrical to the center of each pixel represented by the image signal in synchronization with the waveform of the chopped signal. Accordingly, the interval of dots formed to correspond to each color component is relatively wide when the density value is small, while the interval is relatively narrow when the density value is large.

Image forming method and apparatus thereof with control of dot position

In a method of developing an electrostatic latent image formed on an image bearing member, wherein a developer carrying member carrying a layer of a developer is faced to the image bearing member and is supplied with an oscillating bias voltage to form an oscillating electric field in a developing zone, the improvement residing in: that a maximum Vu1max of a potential difference Vu1 between an image portion potential of the latent image and a potential of the developer carrying member in a transfer phase of the oscillating electric field, is larger than a maximum Vr1max of a potential difference Vr1 therebetween in a back-transfer phase thereof; that a maximum Vu2max of a potential difference Vu2 between a non-image portion potential of the latent image and a potential of the developer carrying member in the transfer phase of the oscillating electric field, is not less than a maximum Vr2max of a potential Vr2 therebetween in the back-transfer phase thereof; that integration Iu2, with time, of the potential difference Vu2 is not more than integration Ir2, with time, of the potential difference Vr2.

Method of developing electrostatic latent image using oscillating bias

An image forming apparatus includes an image forming device for forming an image on a recording material, the image forming device having a contactable member which is contactable with the recording material with electrostatic attraction force between the contactable member and the recording material; a separation discharger for electrically discharging the recording material upon separation of the recording material from the contactable member after image formation on the recording material, the separation discharger having a wire electrode and a shield electrode; wherein Vp/f.ltoreq.0.5 is satisfied where Vp is a conveying speed of the recording material (mm/sec), and f is a frequency of a periodically changing voltage applied to the separation discharger (Hz), wherein the inside of the shield electrode is reduced toward the contactable member.

Image forming apparatus having recording material separating means

A developing apparatus includes a guide member for guiding toner toward an image bearing member bearing an electrostatic image thereon, the guide member having a first end and a second end, a vibration generating device for applying an ultrasonic oscillation to the guide member proximate one of the first end and the second end of the guide member, and a vibration absorbing device for absorbing the ultrasonic oscillation in the guide member at the other one of the first end and the second end, wherein toner is conveyed on the guide member in a direction from the absorbing device to the vibration applying device. In one aspect, the toner is a magnetic toner, and a magnetic field is generated on the guide member at a position opposite a surface for guiding the toner.

Powder conveying device

An ultrasonic oscillation is applied in the neighborhood of one end of a guide member for supporting and guiding a powder, so that a transverse proceeding wave is generated in the guide member. The powder moves from the other end of the guide member toward a position of the applied ultrasonic oscillation under the action of this proceeding wave.

An image forming apparatus using electrostatic images includes a state quantity detection device for detecting states which would exert some influence on the formation of images as quantities, a control quantity control device for controlling the operation of a process for forming images on an image bearing member, a rule storage device for relating the relation between the state quantities and the control quantity by a control device as a certain rule and storing it, and an inference device for inferring a control quantity to be determined from a set of state quantities on the basis of rules of the rule storage device. The picture image forming apparatus determines the operation quantity for the image bearing member of the process device on the basis of the calculated results of the inference device and forms an image.

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Oume, Japan

Nobuyuki Ito