JPH047513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fixing device for an electrophotographic copying machine or the like.

(Prior Art) Conventionally, as a means for detecting the paper ejection status in order to detect a paper jam in the fixing device of a copying machine, the first
As shown in the figure, a micro switch 3 is provided at a suitable position behind the fixing unit composed of a heating roll 1 and a pressure roll 2, and an actuator 4 of the switch 3 is placed at a suitable position on a paper guide plate 5 in the paper transport path. The actuator 4 is arranged in such a manner that detection is made when the discharged paper comes into contact with the actuator 4.

(Object of the Invention) However, in the fixing device having such a configuration, when a paper jam occurs, the support member 7 having the peeling claw 6 is rotated and opened as shown in FIG. 2 to remove the paper jam. If you forget to return the paper to its original position after removing the paper that caused the
Because there is no detection means, the display on the copying machine itself becomes normal, and if you try to make a copy in this state, it will not fix the image because the peeling claw 6 is not arranged on the heating roll 1. There was a drawback that the paper was not peeled off from the heating roll 1 and a paper jam occurred again. The present invention has been made in order to eliminate the drawbacks of the conventional fixing device described above, and is applicable to electrophotographic copying machines, etc., in which the paper ejection detection means can also be used to prevent forgetting to return the support member of the peeling claw. The purpose of the present invention is to provide a fixing device.

(Structure of the Invention) For this purpose, the present invention provides an optical sensor on the lower frame of the paper guide plate behind the fixing unit composed of a heating roll and a pressure roll, and a support member having a peeling claw for the sensor. By rotatably providing an end of a lever for detecting paper ejection at a suitable location, when the peeling claw is placed on the heating roll part, the other end of the lever is placed between the light emitting element and the light receiving element of the sensor. When the paper passes through this area, the other end of the lever is lifted upward by the paper, and the light from the light emitting element is detected by the light receiving element. The presence of paper is detected by converting the detected light into an electrical signal, and when removing jammed paper, the support member that has been opened for this work is not forgotten to return. Since the light from the light emitting element enters the light receiving element at all times, the detection signal is used to activate an appropriate warning device to notify that the user has forgotten to return the device.

(Example) The present invention will be described in detail below based on an example shown in the drawings.

FIG. 3 is a cross-sectional side view showing one embodiment of the fixing device of the present invention, and FIG. 4 is a rear view of the paper discharge detection lever portion of the same.

A light-emitting element 11a and a light-receiving element 11b of an optical sensor 11 are arranged in a frame 10 at the lower part of a paper conveyance path behind a fixing section consisting of a pair of upper and lower heating rolls 8 and a pressure roll 9. On the other hand, the peeling claw 12
A support member 14 is rotatably provided above the fixing unit by a shaft 13, and one end of a lever 15 for detecting paper ejection is rotatably provided by a shaft 16. The part is the light emitting element 1 of the sensor 11.
1a and the light receiving element 11b so that the light emitted by the light emitting element 11a is always blocked. The light emitted by the light emitting element 11a is received by the light receiving element 11b, and by converting this into an electrical signal, the presence of paper can be detected. At the same time, the sensor 11 is provided with a circuit as shown in FIG. A warning is given to the operator by voice or light 18 or the like.

The present invention is constructed as described above. Next, its operation will be explained.

Normally, when a sheet of paper on which an unfixed toner image has been fixed by the heating roll 8 and the pressure roll 9 is discharged, the other end of the lever 15 is pushed upward by the leading edge of the sheet, and the sensor 11 light emitting element 11a of
The light emitted by the light receiving element 11b is received by the light receiving element 11b, which converts the light into an electrical signal to detect the presence of paper. When the paper passes through the lever 15, the other end of the lever 15 automatically activates the light emitting element 11a and the light receiving element 11.
It falls between 1 and 2 to block the light and prepare for the next paper ejection detection. By repeating this operation, paper discharge detection for detecting a paper jam is performed. Also, a paper jam occurred in the roll section, and in order to remove it, the support member 14 was raised above the frame with the shaft 13 as a fulcrum as shown in FIG. If you forget to put it back and try to copy, the lever 15 that is interposed between the light emitting element 11a and the light receiving element 11b of the optical sensor 11 to block light will be lifted above the frame together with the support member 14. Since there is nothing to block the light, the light will be received by the light receiving element 11b for a long time. Therefore, this light will be converted into an electrical signal and sent to the operator via the AND circuit 17 to give a warning by sound or light 18. The support member 14 is not returned to its original position, and if copying is performed in this state, a paper jam will occur again.

(Effects of the Invention) As described above, the present invention uses the tip sensor 11 composed of the light emitting element 11a and the light receiving element 11b as the paper ejection means provided for detecting a paper jam in the fixing section of the fixing device, and 11 is fixed to the frame 10 side at the bottom of the paper conveyance path of the apparatus, and a lever 15 that blocks light from the peeling claw 1
By providing it on the support member 13 side of No. 2, it can be used for both paper jam detection and detection of forgetting to return the support member 14, so the device itself can be simplified and miniaturized, and costs can be reduced. This has the effect of not only making it possible, but also helping to improve reliability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing the conventional fixing device in use, FIG. 2 is a cross-sectional side view showing the same state during paper removal work in a paper jam, and FIG. 3 is the fixing device of the present invention. A cross-sectional side view showing one embodiment of the device;
Figure 4 is the same, rear view of the paper discharge detection lever part, Figure 5
The figure is a cross-sectional side view showing the state during paper removal work in the event of a paper jam, and FIG. 6 is a circuit diagram showing an embodiment of the support member forget-to-return warning device. In the figure, 8... heating roll, 9... pressure roll,
10... Frame, 11... Light sensor, 11a
... Light emitting element, 11b ... Light receiving element, 12 ... Peeling claw, 14 ... Support member, 15 ... Lever, 16
...Axis, 17...ANP circuit, 18...Audio or light.

Claims (1)

[Claims] 1 A peeling claw for fixing a sheet of paper having an unfixed toner image attached between at least two rolls and peeling the paper from the roll, and a support member for supporting the peeling claw, the peeling claw In a fixing device such as an electrophotographic copying machine that rotates a support member to remove jammed paper, a lever for detecting paper ejection that rotates intermittently due to paper contact each time paper passes. is provided on the support member, and an optical sensor is provided to detect the interruption of light due to intermittent rotation of the lever, and a warning is issued based on the fact that the lever is not detected by the optical sensor for a long period of time. A fixing device for an electrophotographic copying machine, etc., characterized by being provided with a means.