JPS5995575A - Fixing device of copying machine or the like using laser - Google Patents

Abstract

PURPOSE:To project heat energy corresponding to an image by detecting the quantity of a laser beam transmitted through a form with a photodetecting element group arranged under a form conveyance path and controlling a laser light source on the basis of its detection signal. CONSTITUTION:A polygon mirror 10 for projecting the laser beam is arranged on the form conveyance path behind the transfer point of a photosensitive body 8 and when the form 16 after transfer reaches there, the form is irradiated with the laser beam for fixing from the polygon mirror 10. This laser beam is transmitted through the form 16 and photodetected by the photodetecting element group 13 arranged under it to output the detection signal corresponding to image information from the photodetecting element group 13 to a control circuit 14. Consequently, the output of a laser light source circuit 15 is controlled to control the radiant heat energy of the laser beam emitted from the laser light source 11 according to the picture information, fixing the unfixed toner image on the form 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electrophotographic copying machine that uses a laser beam to fix an unfixed toner image formed on copy paper. The present invention relates to a fixing device that can control and administer thermal energy according to a toner image.

In electrophotographic copying machines and the like that conventionally used laser beam fixing, the fixing device is equipped with a fixing device that can administer the thermal energy of the laser beam for fixing according to the unfixed toner image formed on the paper. As shown in FIG. 1, a mirror 3 is placed at a position facing the document 2 placed on the platen 1, and the mirror 3 sends the reflected image of the document from the first surface of the platen to the image reading device 4. At the same time as reading the image, the image information is sent to the laser power supply circuit 6 via the control circuit 5, the output of the power supply circuit 6 is controlled according to the image information, and the heat of the laser beam emitted from the laser light source I is controlled. It was proposed to control energy.

However, the fixing device with such a configuration is difficult to deal with due to dirt on the document or platen, transfer of the toner image onto the paper, damage during transportation, and accurate application of thermal energy of the laser beam to the toner image on the paper. This method has disadvantages in that it cannot be controlled, causes uneven fixing, and also causes a loss in energy administration efficiency.

The present invention has been made in order to eliminate the drawbacks of the conventional fixing devices of electrophotographic copying machines and the like. A fixing device for a copying machine or the like using a laser is configured to detect the sight of a laser beam transmitted through a sheet of paper by a group of light-receiving elements, and to administer thermal energy according to the image on the sheet of paper based on the detection signal of the group of light-receiving elements. The purpose is to provide.

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 2 is a schematic diagram showing an embodiment of the fixing device of the present invention.

A rotary polyhedral mirror 10 equipped with a morph 9 is arranged on a paper conveyance path behind the transfer point of the photoreceptor 8.

A laser beam 11 is placed at an appropriate location near the paper conveyance path with respect to the polyhedral mirror 10, and the laser beam emitted from the laser light source 11 is reflected by the polyhedral mirror 10, and as the laser beam rotates, the laser beam 11 is placed in the vicinity of the paper conveyance path. At a predetermined position, a correction lens 12 for optical path correction is disposed in the optical path of the laser beam from the polyhedral mirror 10 to the paper transport path to enable high-speed scanning perpendicular to the transport direction.

On the other hand, a light-receiving element group 13 is disposed below the paper transport path corresponding to the portion to be irradiated with the laser beam, and the receiving block C element group 1
3 detects the amount of light that is equal to the laser beam from the polyhedral mirror 10 that has passed through the paper, and sends the detection signal from the light receiving element group 13 to the racer power supply circuit 15 via the control circuit 14.
and controlling the output of the laser power supply circuit 15,
Thermal energy of a laser beam corresponding to an unfixed toner image formed on a sheet of paper can be administered from a laser light source 11.

The operation of the fixing device of the present invention configured as described above will be described below.

Now, when the paper 16 passes the transfer point of the photoreceptor 8, the developed toner image is transferred to the surface of the photoreceptor 8 by the action of the transfer cocitron 1T.

After completing the transfer, the paper 16 with the unfixed toner image attached goes to the exit outlet outside the machine along the paper conveyance path.
When the tip of the polyhedral mirror 10 is detected, the laser light source 11 is driven by the signal to emit a laser beam, and at the same time the polyhedral mirror 10 also starts rotating. The laser beam emitted from the laser light source 11 is reflected by the polyhedral mirror 10, and as it rotates, the laser beam scans at high speed in a direction perpendicular to the sheet conveyance direction, as shown in FIG.

When the paper 16 with the toner image transferred thereto arrives, the laser beam for fixing from the polyhedral mirror 10 passes through the paper 16 and is detected by the light receiving element group 13 disposed below the paper. Light is received over the width.

At this time, since the light intensity of the transmitted laser beam is different between the image area where the toner image is formed and the non-image area on the paper 1B, the light receiving element group 13 outputs a detection signal according to the image information, and the light receiving element group 13 outputs a detection signal according to the image information. The output of the laser light source circuit 15 is controlled via the control circuit 14 according to the signal, and the radiant heat energy of the laser beam emitted from the laser light source 11 is emitted in accordance with the image information to form a shape on the paper 16. The unfixed toner image is fixed as shown in FIG. Since the scanning motion of the laser beam on the irradiated area due to the rotation of the polyhedral mirror 10 is extremely high, the determination by the laser beam is repeated over the slight progress of the paper 16. The fixed toner image and its surrounding temperature are at the values necessary for fixing at the time of "Aζ", and fixing is carried out evenly.

The present invention is constructed and operated as described above, and when fixing an unfixed toner image on a sheet of paper, the thermal energy of a laser beam necessary for fixing is applied to ITi according to image information. Since the energy can be irradiated, the fixation is not unevenly performed, and there is no energy injection, and therefore energy efficiency can be improved. Also, since this image information is obtained from the area irradiated by the laser beam, it does not stain the original or the platen, and the problem of paper misalignment during transfer and transportation can be almost completely solved.
Furthermore, the light-receiving element group 13, which is placed in the area to be irradiated by the laser beam in order to obtain the image information, is placed under the paper conveyance path, that is, on the back side of the paper, so that the light-receiving element group 13 detects the toner on the paper. The dirt does not spread, so there is an effect that accurate image information cannot be obtained.

It should be noted that there is no particular reason why the present invention is limited to the above-mentioned embodiments, and it goes without saying that the kneading device can be used in, for example, a printing machine in addition to a copying machine.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a fixing device of a conventional laser/C copying machine, FIG. 2 is a schematic configuration diagram showing an embodiment of the fixing device of the present invention, and FIG. FIG. 4 is a perspective view showing the state before fixing, and FIG. 4 is a perspective view showing the state during fixing. 12... Laser light presence, 13... Light receiving element group,
16...Paper. 2nd cause of agony

Claims (1)

[Claims] In a fixing device such as a machine, a group of light-receiving elements is arranged on the paper transport path T corresponding to the portion to be irradiated with the laser beam, and the light-receiving element group detects the amount of light of the laser beam that has passed through the paper, A fixing device for a copying machine or the like using a laser, characterized in that a laser light source can be controlled so as to emit heat energy corresponding to a toner image on a sheet of paper based on the detection signal.