JPS6041349B2 - seat protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet protection device that detects clogging in a sheet heating device.

Conventionally, when thermal fixing is performed using a heater in a copying machine, etc., if a paper jam occurs in the fixing device, a jam detection lever and switch installed on the scarlet paper side roller of the fixing device will automatically remove the sheet on which the image has been formed. The passage time of a certain copy paper is detected, and if the jam switch is still on after a certain period of time has elapsed, the heater is turned OFF to prevent the copy paper from catching fire due to overheating from the heater. However, if the paper jam is detected by the jam detection lever provided on the exhaust side roller as described above, and then the heater is turned FF, it will take time for multiple sheets to reach the gE paper side loaf. It takes about 5 to 5.5 seconds for the heater to turn off after a paper jam occurs, and the inside of the fixing device is
The temperature is quite high at 50 to 300 oo, so turn off the heater.
There was a risk that the copy paper would burn or catch fire before it was FF. The present invention takes the above points into consideration and provides a sorting protection device that can immediately turn off the heater when a paper jam occurs within the heating device. An embodiment of the present invention will be described in detail below with reference to the drawings. 1 shows a fixing device, and a conveying mechanism is provided below it.

This conveyance mechanism consists of rollers 11, 12 and scale paper rollers 13, 1.
4 and a guide plate 17 for supporting copy paper 16 between the two. The lower rollers 1 and 13 of each pair of yarn backing rollers 1 and 12 and paper discharge rollers 3 and 14 are driven by a motor (not shown), and the rollers 1 and 13 of the above example are driven by a motor (not shown).
, 14 are moved by the lower rollers 1, 13. The upper paper roller 2 is provided to support the non-image area of the copy paper so as not to destroy the toner image formed on the copy paper. Since toner tends to adhere to the roller 4, the roller 4 is made very light so that toner does not adhere to the roller 4. Further, the guide plate 17 is made of metal such as aluminum to improve thermal efficiency. Heaters 9 and 20 such as infrared rays are provided at positions facing the guide plate 17.

Reflector plate 2 for radiating heat from this heater 19, 20G
2, and the outside of this reflective plate 22 is covered with a heat insulating cover 23. 24 is a guide wire device, and 25 is a rotatable shaft installed in the main body of the copying machine (not shown).

A plurality of wire-shaped detection bodies 26 whose tips are bent into a fishing shape and can self-maintain their shape are fixed to the shaft 25 at equal intervals. The height h' of the bent tip 27 of the detection body 26 is greater than the thickness of the heat insulating cover 23! Formed tall. In addition, the tip 27 is fitted with a notch 28 formed on the paper discharge side of the heat insulating cover 23, and is hooked onto the upper surface of the heat insulating cover 23. It is designed not to fall. 30 is a detection body fixing plate for moving a plurality of detection bodies 26 of the same shape, and each detection body 26 is fixed with adhesive or the like.

The guide wire device 24 is made of a light material so that it can be easily rotated when the copy paper 16 is bent due to a jam. Note that the detection body 26 is mounted on the shaft 2 so that it can be rotated more easily due to deflection caused by jamming of the copy paper 16.
It is also preferable to extend it in the direction 5 and attach a balancing weight thereto. In addition, when fixing is performed normally, the copy paper 16 can pass through the detection body 26 and the guide plate 17 without touching the detection body 26, and if the copy paper is bent, the copy paper 16 can immediately pass through the detection body 26. They are placed close enough to touch. In addition, when the copy paper 16 is curled, the detection object 26
Since it extends in substantially the same direction as the conveyance direction of the copy paper, it functions to correct this curl and prevents unnecessary jamming.
A microswitch 32 is installed on the heat insulating cover 23 and switches between the heaters 9 and 20.The switch lever 33 is interlocked with the tip 27a of an arbitrary detection object 26a, and the switch lever 33 is activated by the movement of the tip 27a. be done.

In the copy paper protection device configured in this way, when copying is started, the paper feed rollers 11 and 12 and the paper discharge rollers 3 and 1
4 is rotated, and heaters 9 and 20 are turned on.

The copy paper 16 on which the toner image has been formed is fed by paper feed rollers 1, 1.
2, the toner is sent into the fixing device by heaters 19, 201, and is thermally fixed by paper rollers 13, 1.
4, the fixing device 10 prints uneven paper. At this time, the tip 27 of the detection body 26 is held in the notch 28 of the heat insulating cover 23, and the microswitch 23 causes the heater 1 to
9.2 rivers are ON. Further, the copy paper 16 does not touch the detection body 26. The above is a case where no misprints occur; however, for example, the leading edge of the copy paper 16 may be bent, or there may be paper jam.

If a paper jam occurs due to toner adhering to the rollers 13 and 14, the following will occur. Normal detection object 2
6 has its tip 27 supported by the notch 28 of the heat insulating cover 23, but at this time there is a distance of one length between the tip 27 of the detection body and the heat insulating cover 23. After the copy paper 16 has passed over the guide plate 17, if the paper ejection rollers 13 and 14 do not handle the scarlet paper properly and a paper jam occurs, the copy paper 16 is continuously transferred to the fixing device 10 by the paper feed rollers il and 12. Since the copy paper 16 is fed to the fixing device 10, the copy paper 16 is bent inside the fixing device 10. Due to this deflection, the detection body 26 is pushed upward, and its tip 27 rises above the one-length heat insulation cover 23. By this movement of the tip 27 in the x direction, the switch lever 33 of the microswitch 32 is operated in the x direction, and the heaters 9 and 20 connected thereto are turned off. Next, if you remove the copy paper that has caused this paper jam, the guide wire device 24
returns to its original position, the switch lever 33 is operated in the counter-x direction, and the heaters 9, 201 are turned on again. Note that the present invention is not limited to the above-mentioned embodiments; for example, the shaft and the microswitch may be provided on both the paper feeding side and the non-paper side, and detecting bodies may be connected to both sides, and the number of detecting bodies may be arbitrarily selected. .

Further, the operation of the switch may be changed according to the rotation of the shaft instead of the tip of the detection object. Moreover, the paper may be fed by an endless conveyor belt without using rollers and guide plates for the conveyance device. According to the present invention having such a configuration, the following special effects can be achieved as a sheet protection device.

That is, (1) a paper jam can be immediately detected by the deformation of a sheet such as a copy paper in which a paper jam has occurred, so that the heating heater can be shut off immediately;

Therefore, the time required from the occurrence of a paper jam until the heater is shut off can be significantly shortened, and accidents such as sheets burning or catching fire in the heating device can be completely prevented. (2) Since the detection body also functions as a guide member, there is no risk that the sheet will be overheated due to the sheet approaching the heater. (2) Since the guide wire extends in substantially the same direction as the sheet conveyance direction, the leading edge of the sheet being conveyed does not get caught, but rather has the effect of assisting sheet conveyance. ■ The detection body itself detects the deformation of the sheet by its vertical movement, and this detection action activates the switch, so the detection body itself cannot become a dangerous obstacle during jam removal, and the operability is significantly improved. Improve.

(2) Since the detection body detects paper jams in sheets not by the deformation of the guide wire, but by the movement of the guide wire, damage to the detection body can be kept to a maximum of 4.

Therefore, a reliable detection operation can be performed at all times. (2) Since the guide wire is provided over the heating device, jams occurring in any part of the heating device can be reliably detected.

Furthermore, since the heater is immediately shut off when a jam is detected, it is extremely reliable as a sheet protection device. (2) Furthermore, since the guide wire does not interfere with the progress of the sheet in the normal conveyance state, the inconvenience caused by providing a sheet protection device can be eliminated, and the sheet can be protected reliably.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a perspective view showing the fixing device, FIG. 2 is a sectional view taken along the line n-0 in FIG. 1, and FIG. The figure is a partially perspective view, and FIG. 4 is a partially enlarged view. 17...Guide plate, 19,20...Heater, 22
...Reflector, 24...Guide wire device, 32
……Microswitch. O / Figure O 2 Figure O 3 Figure O 4

Claims (1)

[Claims] 1. A conveying mechanism for conveying a sheet, a heat fixing section installed at an opposing position on the upper part of the conveying mechanism, and a heat fixing section that is pivotally supported on the upstream side of the conveying mechanism in the sheet conveying direction and extending in substantially the same direction as the sheet conveying direction. The sheet is disposed at a position to cover the heat fixing unit facing the conveyance mechanism and to guide the sheet conveyed by the conveyance mechanism, so that when the sheet becomes jammed in the heat fixation unit, the sheet A detecting body consisting of a guide wire that can be moved up and down while maintaining its own shape, and a heater changeover switch that is electrically separate from the detecting body and can be operated by the vertical movement of the detecting body. Seat protection device consisting of.