Kabushiki Kaisha Tec

Tokyo Electric Co.

Toshiba Tec Kabushiki Kaisha

Kei Hara

Shigeru Morino

Hiroshi Yamaguchi

Koki Tanaka

Yoriyuki Sunaga

Osamu Kobuse

A thermal printer applies heat to print a multicolor image on a heat-sensitive paper having a stack of color development layers which have different development characteristics. The printer includes a paper feed motor for feeding the heat-sensitive paper, and a thermal line head for heating the heat-sensitive paper fed by the paper feed motor. Particularly, the printer further includes a CPU for performing a print control process of driving the thermal line head such that each part of the heat-sensitive paper develops a specific color depending on the number of times thermal energy has been applied to the part. The thermal energy is not higher than the lowest of different thermal energies which are required for developing the color development layers.

Thermal printer

An exposing device is composed of a photosensitive drum having a surface partitioned into a plurality of exposure areas in a main scanning direction, for carrying an image formed by exposing the surface, a laser light source for emitting a laser beam, a polygon mirror for rotating at a constant speed to scan the surface of the photosensitive drum in the main scanning direction with the laser beam from the laser light source, and an exposure control circuit for producing items of emission data for one line while the number of emission data items for one dot is varied for each exposure area, and for supplying the emission data items for one line to the laser light source in response to a print clock pulse. Particularly, the exposure control circuit includes a CPU for multiplying a reference value for the number of data items which should be selected from emission data items for a dot and changed in value to obtain a predetermined function, by a coefficient for an exposure area to which the emission data items for the dot are assigned, and for changing the value of each data item selected from the emission data items for the dot in number corresponding to a result of multiplication.

Exposing device for correcting an f.theta. error of a rotatable polygon

A color printer includes an electrophotographic process unit for selectively exposing the photosensitive image carriers to form identical latent images thereon, developing the latent images as toner images by supplying toners of different colors, and transferring the toner images onto paper, and a control circuit for controlling amounts of exposure of the latent images to be formed by the electrophotographic process unit. Particularly, the control circuit includes a toner-save key for selecting a toner-save mode, and processing circuit for lowering the exposure amounts of the latent images in the toner-save mode, while changing a rate of the exposure amounts to compensate for a difference between development properties of the toners.

Color printer

A method and an apparatus for driving an edge emission type line head having a plurality of edge emission type EL elements grouped in blocks. Each group of the edge emission type EL elements has a channel electrode connected to a channel driver and has a common electrode connected via a matrix circuit to common terminals of a common driver. The channel driver outputs voltages while the common driver outputs alternately a positive and a negative high voltage. If something happens to stop the function of the line head in operation, the output of the common driver is stopped after a pair of a positive and a negative high voltage is output by one common terminal, or after one-line output is effected by the common driver. This helps prolong the service life of the edge emission type EL elements constituting the line head.

Method and apparatus for driving edge emission type line head

An apparatus for driving edge-emission type electroluminescent elements to emit light to expose an image carrier and to form image data clearly on the image carrier. The edge-emission type electroluminescent elements have electrodes and emit light when a potential difference across the electrodes exceeds a preset threshold value. Electric pulses are supplied to the electrodes of the edge-emission type electroluminescent elements to cause the potential difference across the electrodes to exceed the preset threshold value so that the edge-emission type electroluminescent elements emit light. A series of pulses are supplied for each pixel of image data. The series of pulses includes a first set of pulses supplied at a first cycle to cause the edge-emission type electroluminescent elements to emit light to expose the image carrier, and a second set of pulses supplied at a second cycle slower than the first cycle to cause the edge-emission type electroluminescent elements to emit light to maintain exposure of the image carrier.

Method and apparatus for driving edge-emission type electroluminescent

An exposure method for use in an image forming apparatus for having each of edge emission type electroluminescent (EL) devices emit light a plurality of times to form one pixel of an image. The gradient of the image outline relative to the horizontal scanning direction is checked to see if it falls in one of two ranges: between 0.degree. and 45.degree., or between 45.degree. and 90.degree.. If the gradient falls between 0.degree. and 45.degree., the edge emission type EL devices are made to emit light selectively according to the proportion of image-filled regions in the pixels intersected by the outline. If the gradient falls between 45.degree. and 90.degree., either the light intensity of the edge emission type EL devices is established according to the proportion of image-filled regions in the pixels intersected by the outline, or the number of the pulses which exceed a threshold voltage and which are fed to the edge emission type EL devices is gradually reduced according to reductions of image-filled regions in the pixels intersected by the outline.

Method and apparatus of exposure for correcting electrostatic latent

An apparatus for maintaining an electrophotographic apparatus with at least a photosensitive member comprises a first memory for storing a count value for the number of prints, and a second memory for storing the number of replacements of the first memory when the count value for the number of prints has reached a value based on which a decision is made whether the service life of the photosensitive member is expired. When it is determined that the value stored in the second memory has reached a predetermined value, a user is informed of the maintenance period of other maintenance-requiring components than the photosensitive member.

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Shizuoka-ken, Japan

Kei Hara