JPS5995576A - Fixing device of copying machine or the like using laser - Google Patents

Abstract

PURPOSE:To control the irradiation of a laser beam with the accurate quantity of light during fixing by providing a photodetecting element which detects the quantity of light to the overall scanning amplitude of the laser beam under a form conveyance path, and controlling the output of the laser beam on the basis of its detection signal. CONSTITUTION:The laser beam radiated by a laser light source 11 driven with a form front-end detection signal scans on the photodetecting element 13 to its overall length through a polygon mirror 10 and the quantity of the laser beam is detected to the overall length before the form 17 reaches the irradiation point, sending the detection signal to a control circuit 14. Consequently, the output level of a laser power source circuit 15 is set to a specific value and the form 17 conveyed thereto is irradiated with the laser beam controlled to a specific output; and the unfixed toner image on the form 17 and its circumference rise in temperature enough for fixing, which is carried out uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device that uses irradiation thermal energy of a laser beam to fix an unfixed toner image formed on copy paper.

Conventionally, a fixing device such as an electrophotographic copying machine using a laser has a laser light source 2 disposed near the paper conveyance path behind the transfer point of the photoreceptor 1, as shown in FIG.
Rotating polyhedral mirror 3
and by its rotation, the position of the leading edge of the advance paper transport path can be repeatedly scanned at high speed perpendicular to the transport direction, and the unfixed spots formed on the copy paper by the irradiated thermal energy during this scanning are In addition to fixing the toner image, a mirror 4 for optical path switching is rotatably arranged in the optical path of the laser beam from the laser light source 2 to the polyhedral mirror 3, and the mirror 4 allows the laser beam from the laser light source 2 to be fixed. The beam is reflected by the light receiving element 5, and the light receiving element 5 detects the amount of light, and the detection signal from the light receiving element is sent to the laser power supply circuit 7 via the control circuit 6, and the output of the power supply circuit 7 is transmitted to the laser power supply circuit 7. The laser light source 2 is configured to control and emit a laser beam suitable for fixing.

However, in the fixing device having such a configuration, information on the light amount of the laser beam cannot be obtained in the fixing section.
In addition, since the light-receiving element 5 itself for obtaining the intensity information of the laser beam is a single light-receiving section, it is impossible to obtain information over the entire scanning width of the beam. When fixing, the unfixed toner image formed on the paper has disadvantages such as the inability to accurately control the irradiation of the laser beam to both the center and surrounding areas.1. At times, there was a drawback that the optical path of the laser beam had to be switched successively using the mirror 4.

The present invention has been made in order to eliminate the drawbacks of the conventional fixing devices for electrophotographic copying, etc. The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional fixing devices such as those for electrophotographic copying. A light receiving element that detects the light amount over the entire width is arranged, and the light amount of the laser beam is measured at the fixing section and also over the entire scanning width, and the output t of the laser beam is determined by the detection signal.
An object of the present invention is to provide a fixing device for a copying machine or the like using a laser, which is controlled.

The present invention will be described in detail below based on an embodiment shown in FIG.

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 a suitable position near the paper conveyance path with respect to the polyhedral mirror 10, and the laser beam irradiated from the laser beam 11 is reflected by the polyhedral mirror 9 to a predetermined position on the paper conveyance path. By the rotation, the portion can be repeatedly scanned at high speed perpendicularly to the conveying direction, and the polyhedral mirror 10
A correction lens 12 for optical path correction is disposed in the optical path of the laser beam from.

On the other hand, □ below the paper conveyance path and the polyhedral mirror 1
A light receiving element 13 is disposed over the entire scanning width of the beam in the area to be irradiated with the laser beam from 0, and the light receiving element 13 is connected to a laser power source 15 via a control circuit 14
By connecting to the laser beam, the light intensity of the laser beam is detected over the entire length, and the detection signal is sent to the control circuit 14.
The output of the laser power supply circuit is controlled via the control circuit 14 so that it can be set to a predetermined output.

The operation of the settling device of the present invention planted as described above will be explained below.

The sheet IT, on which the developed toner image is transferred once by the transfer corotron 16 onto the surface of the photoreceptor 8 at the transfer point of the photoreceptor 8, is conveyed along the sheet conveyance path toward the paper discharge port outside the machine. When the leading edge of the paper is detected by a paper leading edge detection device (not shown) in the process of bringing the paper, the paper leading edge detection device sends a signal to the laser light source 11, which drives the laser light source 11 to emit a laser beam. also starts rotating. Along with this, the laser beam starts scanning over the entire length of the light receiving element 13 as shown in FIG. The light receiving element 13 detects the light intensity of the laser beam over the entire length of the paper 17 before it reaches the location, and sends the signal to the control circuit 14. Control circuit 1
4 stops controlling the racer power supply circuit 15 by this signal, sets the output level of the laser power supply circuit 15 to a predetermined value, and accordingly sets the output of the laser beam emitted from the laser light source 11 to a predetermined value. to hold.

This fall, the paper 1T is transported through the paper transport path to the UVC 6, and as shown in FIG. 4, the unfixed toner image formed on its surface is melted by the thermal energy of the laser beam. It will become established. In this state, since the rotation rate of the polyhedral mirror 10 is extremely high, high-speed scanning is performed repeatedly for the slight advancement of the paper 17, and the temperature of the unfixed toner image on the paper 17 and its surroundings increases. Fixing is performed evenly with the value required for fixing.

The present invention is configured and operates as described above,
The light receiving element 13 that detects the light intensity of the laser beam is placed under the paper conveyance path corresponding to the area to be irradiated with the laser beam, so that the photometry of the paper can be performed at that location, resulting in high photometry accuracy. Accurate output control is possible.

Since the light receiving element 13 can emit side light over the entire scanning width of the laser beam, it is possible to control the output of the laser beam between the central part and the peripheral part of the paper, and it is possible to eliminate variations in constant humidity. Alternatively, unlike conventional fixing devices, there is no need to use a switching mechanism to switch the optical path of the laser beam between photometry and fixing. It has the following effects.

It should be noted that there is no reason why the present invention should be limited to the above-mentioned embodiment, and it goes without saying that the present invention can be provided and used in a printing device, etc. in addition to the above-described copying machine.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional copying reservoir device using a laser, FIG. 2 is a schematic configuration diagram showing an embodiment of the fixing device of the present invention, and FIG. FIG. 1 is a perspective view showing the previous state, and FIG. 4 is a perspective view showing the state at the time of fixing. 11... Laser light source, 13... Light receiving element. 1st prisoner

Claims (1)

[Claims] In the fixing device used in 81% of electrophotographic copying, in which an undefined toner image transferred to the surface of copying paper is irradiated and heated with a laser beam to fix it, a scanning laser beam is applied to the paper transport path T corresponding to the area to be irradiated with the laser beam. A laser characterized in that a light-receiving element for detecting the light intensity of the laser beam is provided over the entire width, and the output of the laser beam irradiated from the laser light source is controlled by a detection signal from the light-receiving element. A fixing device for copying machines, etc. that uses