Iwatsu Electric Company Ltd.

Norio Kokaji

Kunio Kinoshita

Toshihiro Urano

Michiaki Yokozawa

Katsunori Saitoh

Nobuyuki Shimada

Mamoru Nishiguchi

Seiichi Hayashi

Yuuichi Nakagawa

Katsunori Saito

The present invention is aimed at providing a control system for a thermal fixing apparatus having an excellent fixing ability even at an initial stage of a copying process when applied to a high speed copying machine and ensuring a longer life of a surface layer member of the roller, while maintaining the economical benefit derived from the provision of a heater only in a heat roller. The fixing apparatus includes a heater roller 101 and a press roller 102. At least one of the rollers is driven by a motor 103 while in contact with the other so that both rollers are rotated together. A surface temperature of the heater roller 101 is detected by a thermometer 104 and is used for controlling a heating level of a heater 106 by a controller 105. A standby stage controller 110 stops the rotation of the motor 103 if it is determined that the surface temperature of the press roller detected by a thermometer 107 is higher than the upper limit temperature, and outputs a command for rotating the motor 103 if it is determined that the surface temperature of the press roller is lower than the lower limit temperature.

Control system for heat fixing apparatus

In a magnetic printing machine including at least two recording frequency generators which generate at least two recording frequencies with close each other, a recording current applied to a recording head for the same gradation level is switched among at least two recording frequencies every time a predetermined number of pixels are recorded.

Method and an apparatus to record with plural gradation for magnetic

When latent images in a magnetic printing apparatus are recorded and developed, a magnetic pattern which has one direction and which has at least two magnetic transfer regions is formed at one-dot black picture regions on a recording medium. When the black picture regions have two or more dots, beside the magnetic pattern having one direction, at least one magnetized pattern having the other direction is formed therein. A white picture region is formed by a magnetized pattern which is longer than the magnetized pattern in the black picture region and which has the other direction. The developing magnetic field is formed in the same direction as that of the other direction. A print having high resolution can be obtained by mutual action between the developing field and the magnetic field generated by the magnetized pattern for the recording.

Method for recording and developing latent images in magnetic printing

Apparatus for forming latent images in a magnetic printing apparatus provides a recording head having a plurality of channels. Among the plurality of channels, some channels are selected and set in accordance with the scanning line density. The selected channels are used in combination, and the loci described by succeeding channels will partly overlap the loci described by the preceeding channels.

Magnetic recording apparatus with adjustable line density

A method and apparatus for forming latent images in which all channel heads are used in different line density scanning. In the case of a multi-channel head having at least three channels which are positioned with a constant distance, the order of the arrangement of loci of the respective channels is made to correspond to two normal and reverse sets of line densities, so that recording at two different line densities can be made by one multi-channel head.

Method and apparatus for forming magnetic latent images

A magnetic printing apparatus provides a recording head having a plurality of channels with different tracking widths. A locus is described by a preceding channel having a wide tracking width, another locus is described being partly overlapped on said locus by using a succeeding channel having a narrow tracking width. The width of locus described by the preceding channel is so corrected as will become nearly equal to the tracking width of the succeeding channel, while the overlapped portion of said locus is written into the succeeding channel.

Method for forming a latent image and apparatus for carrying out the same

In a magnetic duplicator using a magnetic printing machine, reflected light from a document is converted into an electrical video signal by a photoelectric converting element, and the electrical video signal is supplied to plural channels of the magnetic recording head to form a magnetic latent image on a magnetic recording drum, in the latent image forming mode. In the copy mode, the magnetic latent image is developed by a magnetic toner, and the toner picture is transferred onto a recording paper which runs through a paper transport path. The transferred toner picture is fixed on the recording paper, and the remaining toner on the surface of the magnetic recording drum is cleaned after the transfer operation. When the magnetic latent image is formed on the recording drum, the plural channels of the magnetic recording head are moved along the axial direction of the recording drum. In the movement, a relative movement between the magnetic recording drum and the magnetic recording head in the peripheral direction of the magnetic recording drum is effected as the primary scanning, and a relative movement between the magnetic recording drum and the magnetic recording head along the axial direction of the magnetic recording drum is effected as the secondary scanning. The plural channels of the magnetic recording head are arranged with a track pitch i.e., distance apart, which is a predetermined multiple of one unit distance of the secondary scanning i.e., the distance of one pitch of the secondary scanning. And there is provided a control circuit for effecting the secondary scanning so that the spacing between loci of the channels of the magnetic recording head formed on the magnetic recording drum by the previous primary scanning is filled with loci of the channels of the magnetic recording head formed on the magnetic recording drum by the subsequent primary scanning, and processing the video signals in accordance with the secondary scanning.

Magnetic printing machine employing a multi-channel recording head with

In a magnetic copying machine, a reflected light from an original copy is converted into an electrical signal, and supplied to a magnetic recording head to form a magnetic latent image on a magnetic recording drum. The magnetic latent image is developed by a magnetic toner, and the toner picture is transferred onto a recording paper. The transferred toner picture is fixed on the recording paper, and the remaining toner on the surface of the magnetic recording drum is cleaned after the transfer operation. When the copy magnification factor is larger than one, the pulse interval of clock pulses generated in synchronization with the rotation of the magnetic recording drum for reading out the electrical signal is made longer than that used with actual-size copying, and the movement of the magnetic recording head in the axial direction of the magnetic recording drum per one revolution of the magnetic recording drum is made larger than that used with actual-size copying. When the copy magnification factor is smaller than one, the pulse interval of clock pulses generated in synchronization with the rotation of the magnetic recording drum for reading out the electrical signal is made shorter than that used with actual-size copying, and the movement of the magnetic recording head in the axial direction of the magnetic recording drum per one revolution of the magnetic recording drum is made shorter than that in the actual-size copy.

Copy magnification change apparatus in magnetic copying machine

A copying machine comprises an imaging mechanism and a recording mechanism. An imaging sub-scan carriage of the imaging mechanism is scanned in the sub-scanning direction between an imaging start position and an intermediate position to image a master. The recording mechanism includes a recording medium such as a recording drum and a recording sub-scan carriage. The recording medium rotates in the main scanning direction while the recording sub-scan carriage scans in the sub-scanning direction perpendicular to the main scanning direction. When the imaging sub-scan carriage is scanning for one line, the recording sub-scan carriage is also scanning for one line, during which the recording medium performs one main scan so that a latent image of one line of the master can be formed on the recording medium. In response to the first sub-scan of the imaging sub-scan carriage between start and intermediate positions, the recording sub-scan carriage conducts the sub-scan between start and intermediate positions in relation to the recording medium. In response to the subsequent sub-scan of the imaging sub-scan carriage between start and intermediate positions, the recording sub-scan carriage conducts the sub-scan between intermediate and termination positions, so that a TWIN-COPY latent image of the master which is imaged by the imaging sub-scan carriage can be formed on the recording medium.

Copying machine

In a duplicator, a reflected light from a document or an original copy is converted into an electrical video signal by an image pickup element, and the electrical video signal is supplied to a magnetic recording head to form a magnetic latent image on a magnetic recording drum, in the latent image forming mode. In the copy mode, the magnetic latent image is developed by a magnetic toner, and the toner picture is transferred onto a recording paper which runs through a paper transport path. The transferred toner picture is fixed on the recording paper, and the remaining toner on the surface of the magnetic recording drum is scraped after the transfer operation. A set value of a copy register is compared with a counting value of a copy counter by a comparator. When the counting value reaches the set value, a copy end signal is generated. With the pushing of a copy switch, a control portion of the duplicator operates, first for the latent image forming mode and then for the copy mode. The copy mode is maintained without returning to the latent image forming mode, until the copy end signal is generated.

Magnetic duplicator with multiple copies

Disclosed is a magnetographic apparatus wherein a large number of copies of the same picture is produced by repeatedly using a recording drum on which a latent image of the picture is recorded, which apparatus is different from a conventional magnetographic apparatus wherein a sequence of processes consisting of a latent image recording process, a process of developing the image and a process of transferring the image is effected for production of each copy. Further disclosed herein are structural elements of a magnetographic apparatus which are suitable for producing a large number of copies of the same picture by repeatedly using a recording drum as described above.

Magnetographic apparatus

Disclosed is a method and apparatus for carrying out Magnetography utilizing the relationship between half-tones of a picture and the spatial recording density on a magnetic recording material. The picture signal is converted into an electrical signal, whose frequency corresponds to the half-tones of the picture and results in the variation of the spatial recording density so that the naturalness of the half-tones of the picture is successfully preserved.

Method and apparatus for recording latent images on a magnetic medium in

Disclosed is a method wherein, in order to prevent background stains in the conventional NRZ system latent image recording method for Magnetography, the latent image recording is effected in such a manner that, in response to a black color representation signal, the direction of the magnetizing field along a generated magnetizing track is periodically reversed, while in response to a white color representation signal, a saturation magnetizing field of a uniform predetermined polarity is applied to adjacent tracks lying in a white region of the signal.

Method and apparatus for recording latent images for magnetography

A magnetic recording method and apparatus is disclosed. The magnetic recording method includes forming a magnetic latent image on a recording medium with a scanning recording head so that the magnetic latent image has substantially the same width as that of the recording head, recording the magnetic latent image again with the recording head shifted from its first position by a predetermined width to cause overlapping to form a magnetic latent image with a predetermined width narrower than the width of the recording head and making the narrowed magnetic latent image visible.

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Hino, Japan

Norio Kokaji