JPH047514B2 - - 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 paper discharge detection means for detecting a paper jam in a fixing device of a copying machine, a micro switch 3 is installed behind a heating roll 1 and a pressure roll 2, as shown in FIG. The actuator 4 of the switch 3 is disposed along the paper transport path, and the actuator 4 of the switch 3 is configured to detect when the discharged paper comes into contact with the actuator 4.

(Object of the Invention) However, if the actuator 4 of the micro switch 3 for detecting paper ejection is provided at the lower part of the passing surface in the paper conveyance path as in the above-mentioned fixing device, the actuator 4 is attached to the paper when removing a paper jam.
However, there are disadvantages in that the actuator 4 may become wedged, making it difficult to remove the paper, or the actuator 4 may be deformed by pulling the paper. Furthermore, when the operator inserts his/her hand into the fixing unit to remove the paper, the actuator 4 is protruding onto the paper conveyance path as shown in Figure 2, so if the operator touches this actuator 4, his or her hand may be injured. This also has disadvantages in that the operating amount of the actuator 4 changes depending on the stiffness of the paper, forcing adjustment, and that the switch itself causes false detection.

The present invention has been made to eliminate the drawbacks of the conventional fixing device described above.

(Structure of the Invention) For this purpose, the present invention arranges an optical sensor composed of a light emitting element and a light receiving element in a lower frame in the paper conveyance path behind the heating roll and the pressure roll, and One end of a thin plate-like lever of an appropriate shape is rotatably provided at a suitable location on the support member having a peeling claw, and the other end of the lever is inserted between the light emitting element and the light receiving element of the sensor to emit light. At the same time, the other end of the lever is pushed upward by the leading edge of the paper when it is ejected.
The light emitted by the light emitting element is received by the light receiving element, which is converted into an electrical signal to detect the presence of paper, and when removing jammed paper, the lever is rotated above the fixing unit together with the support member. This allows the paper to be ejected normally without deforming the lever or injuring the operator's hand when removing the paper, and regardless of the stiffness of the paper. The object of the present invention is to provide a fixing device for an electrophotographic copying machine or the like that is capable of detection.

(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.

An optical sensor 8 is installed in the frame 7 at the bottom of the paper conveyance path behind the pair of upper and lower heating rolls 5 and pressure rolls 6.
A light emitting element 8a and a light receiving element 8b are arranged. On the other hand, the other end of a thin plate-shaped paper ejection detection lever 12 is attached to a suitable position of a support member 11 which has a peeling claw 9 and is rotatably provided above the fixing unit by a shaft 10.
3, and the other end of the lever 12 is connected to the light emitting element 8a and the light receiving element 8b of the sensor 8.
The structure is such that the light emitted from the light emitting element 8a is blocked by entering the space between the light emitting elements 8a and 8a.

Next, the operation of the fixing device of the present invention configured as described above will be explained.

When detecting paper discharge, the other end of the lever 12 is located between the light emitting element 8a and the light receiving element 8b of the optical sensor 8. Then, when a sheet of paper with an unfixed toner image fixed thereon by a heating roll 5 and a pressure roll 6 is conveyed, and the leading edge of the paper comes into contact with the shaft 1,
3 as a fulcrum, the light emitting element 8a
The light emitted by the paper is received by the light receiving element 8b, and the presence of the paper is detected by converting the received light into an electrical signal. When the entire paper has passed through this point, the lever 12 returns to its original position due to its own weight, blocks the light emitted by the light emitting element 8a, and prepares for the next paper discharge detection.

Furthermore, when removing jammed paper, the lever 1 is lifted by rotating the support member 11 having the peeling claw 9 above the fixing unit about the shaft 10 as a fulcrum.
2 also moves above the fixing section together with the supporting member 11 and is separated from the rear of the heating roll 5 and pressure roll 6.The operator maintains this state and inserts his/her hand into the fixing section to remove the paper. After removing the jammed paper, the support member 11 can be rotated about the shaft 10 and returned to its original position. In this way, the other end of the lever 12 can be moved again. Light emitting element 8 of optical sensor 8
It enters between the light-receiving element 8b and the light-receiving element 8b to block light.

(Effects of the Invention) The present invention is configured and operates as described above, and includes a light-emitting element 8a and a light-receiving element 8b in the paper ejection detection means used for detecting a paper jam in the fixing section.
Using an optical sensor 8 consisting of
is fixed to the lower frame 7 in the paper conveyance path behind the fixing unit, and a lever 12 that serves as a shutter for repeatedly receiving and blocking light in the optical sensor 8 is attached to the support member 11 side.
Since the support member 11 is provided so that the paper can be rotated above the fixing unit and removed from the paper conveyance path, the paper cannot be pulled against the lever 12 when removing the paper in the event of a paper jam. There is no possibility of deforming the paper by hanging the paper, and even if the operator inserts his/her hand into the fixing section to remove the paper, there is no risk of injury to the operator's hand by touching the lever 12, so the work can be done easily and quickly. The lever 12 does not change its operating amount regardless of the stiffness of the paper, so the presence or absence of paper can always be detected under normal conditions, and there is no need for adjustment. This also has the effect of eliminating the occurrence of false detections and helping to improve the reliability of the device itself.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view showing the state of a conventional fixing device when it detects paper ejection, FIG. 2 is a cross-sectional side view showing the state when paper is removed in the event of a paper jam, and FIG. FIG. 4 is a rear view of a paper ejection detection lever section, and FIG. 5 is a cross-sectional side view showing a state when paper is removed from a paper jam. In the figure, 5... heating roll, 6... pressure roll, 7
... Frame, 8 ... Light sensor, 8a ... Light emitting element, 8b ... Light receiving element, 9 ... Peeling nail, 10 ...
...Shaft, 11...Support member, 12...Lever, 13
……shaft.

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. A fixing device for an electrophotographic copying machine or the like, characterized in that the supporting member is provided with a light sensor for detecting interruption of light due to intermittent rotation of the lever.