JPS61165768A - Jam detecting mechanism of copying machine - Google Patents

Abstract

PURPOSE:To detect without fail, easily and instantaneously whether or not a copying paper is wound to a thermal roller by providing the thermal roller provided a guide groove at the side where the copying paper is always contacted and sliding and guiding the tip of the lever of the detecting switch in the always stable condition at the guiding groove. CONSTITUTION:So as to bridge both side walls 102 and 103 of a frame 101 having almost a U-shaped shape, a thermal roller 33 and a pressure roller 34 are provided in the contacting condition. At the side where a copying paper always passes out of the tip of the thermal roller, a ring-shaped guide groove 331 provided up to the prescribed depth is formed. At the outside of a frame side wall 102 of the side which provides the guide groove, a detecting switch 332 to detect whether the winding is present or absent is provided through a bracket 334 to a paper discharging side of the thermal roller, and a lever 333 of a detecting switch 332 penetrates the side wall 102, and the tip is guided by the guiding groove 331 of the thermal roller 33. At the bottom surface of the frame 101 a guide plate 49 to guide normally the thermally stabilized copying paper is provided.

Description

Detailed Description of the Invention (a) Field of Industrial Application The present invention relates to a jam detection mechanism in a copying machine, and particularly in a type of copying machine that transports and copies copy paper on a one-sided basis. Among the various troubles encountered in a copying machine that immediately detects the wrapping of copy paper around a heated roller, one of the most common troubles is the occurrence of a copy paper jam.

As a method for immediately detecting the occurrence of such a jam, a plurality of detectors are installed along the copy paper conveyance path.
Means for detecting the occurrence of the jam by operating these detectors has been proposed and implemented as prior art.

For example, microswitches are installed along the copy paper transport path near the cassette ejection port, near the bottom of the photosensitive drum, near the paper ejection roller, etc., and the levers of these microswitches are set near the bottom of the copy paper transport path. Alternatively, microswitches are disposed along the conveyance path of the copy paper near the paper ejection roller, and the microswitches are activated by bringing the conveyed copy paper into contact with the levers of these microswitches. . Then, by comparing the contact time with a time previously set based on the setting location of the microswitch and the conveyance speed of the copy paper, it is determined whether or not the copy paper has passed the location safely.

On the other hand, the heat roller in the heat fixing device is made of synthetic resin such as Teflon, and silicone oil is sometimes applied to the surface of this heat roller in order to remove toner adhering to the heat roller. , copy paper tends to get wrapped around the heated roller.

Furthermore, due to the structure of the copying machine, the heat roller is generally located in a position that is difficult to see from the outside even when the copying machine cover is removed. It is often difficult to reliably visually confirm this. Therefore, the operator may have no choice but to reattach the copying machine cover to the copying machine body and continue the copying operation. Moreover, because of its function, the heat roller is constantly heated to a high temperature (approximately 200°C), so there is no danger that copy paper wrapped around the surface of the heat roller will burn or, in the worst case, catch fire. I can't say. However, at least in the prior art, the above-mentioned wrap detection means and wrap display means are not currently employed.

(C) Objective An object of the present invention is to propose a jam detection mechanism for a copying machine that can easily and immediately detect whether copy paper is wrapped around a heat roller.

(d) Structure The jam detection mechanism according to the present invention is implemented in a type of copying machine that transports and copies copy paper on a one-sided basis, and is a thermal jam detection mechanism in which a guide groove is provided on the side of the copy paper that is constantly in contact with the copy paper. There is a roller, and the lever of the detection switch is constantly slidingly guided in this guide groove, and the moment the copy paper is about to wrap around the heat roller, the edge of the copy paper comes into contact with the lever of the switch, A detection switch is activated to instantly detect wrapping.

(e) Embodiment FIG. 1 is a simplified vertical cross-section of an embodiment of a copying machine to which the present invention is applied.

First, the general configuration and operation of a copying machine will be explained, and then the jam detection mechanism, which is the main part of the present invention, will be explained.

Copy paper in cassette 2.3 attached to the side of the machine 15.
4 are selectively fed one by one from the cassette 2.3 by a feed roller 6.7 and transported by a transport roller 8.9.10.

A document 12 is placed on a horizontal transparent plate 11 provided at the top of the machine 1.
is in close contact with the document holding cover 13. The exposure lamp 14 illuminates the original 12 through the transparent plate 11, and the original image is transmitted to the photosensitive drum 2 through the reflecting mirrors 16 and 17, the in-mirror lens 19, and the reflecting mirror 20 of the optical device 15.
The image is formed on 1.

The exposure lamp 14 is provided with a reflection plate 22 for efficiently irradiating the original 12 with light from the exposure lamp 14 .

During exposure, the exposure lamp 14, reflector 16, and reflector plate 22 move in the exposure movement direction indicated by the arrow 23 from the paper feed position indicated by the solid line to the position 24 indicated by the imaginary line. , and returns to the original paper feeding position by moving in the opposite direction of the arrow 23. As the exposure lamp 14, reflecting mirror 16, and reflecting plate 22 move, the reflecting mirror 17 also moves, and when the exposing lamp 14, reflecting mirror 16, and reflecting plate 22 are at position 24, the reflecting mirror 17 moves along the virtual line. It is located at position 25 shown by .

On the other hand, the document image is formed on the photosensitive drum 21 charged by the corona discharger 26, so that an electrostatic image is formed on the surface of the photosensitive drum 21.

This electrostatic image is visualized into a toner image by the developing device 27. This toner image is transferred onto the copy paper 4.5 conveyed from the conveyance roller 10 by the action of the corona discharger 28. The copy paper 4.5 on which the toner image has been transferred is reliably peeled off from the photosensitive drum 21 by a peeling claw 29 and a peeling roller 30, and is conveyed to a thermal fixing device 31. The heat fixing device 31 includes a heat roller 33 having a built-in heater 32 and a pressure roller 34 in pressure contact with the heat roller 33.

The peeling claw 29 has a nail-like shape with a predetermined thickness, and the edge surface of the photosensitive drum 21 corresponds to the position of the peeling claw 29. A guide groove for guiding a peeling claw (not shown) is formed in an annular shape at the end of the drum (meaning outside the effective range of copying).

The copy paper after the transfer passes between the heat roller 33 and the pressure roller 34, whereby the toner is thermally melted and fixed. The copy paper 4.5 that has been fixed is transferred to the transport roller 35.
The paper passes through a paper ejection roller 36 and is ejected into a tray 37 provided on the side of the machine.

Reference numeral 38 denotes a cleaning device for cleaning the surface of the photosensitive drum 21 after transfer, which includes a blade 39 for scraping off toner remaining on the surface of the photosensitive drum 21 and a blade 39 for scraping off the toner remaining on the surface of the photosensitive drum 21. A guide plate 40 is built in to guide the inside of the cleaning device.

41.42 is a copy paper filling detection switch for detecting whether or not there is copy paper 4.5 in the cassette 2.3.

43 is an operation detection switch for detecting the above-mentioned copying operation, and 44.45 is a cassette discharge switch for detecting when copy paper 4.5 is fed from the cassette 2.3 to the transport roller 8 side. Paper feed detection switch installed near the exit, 4
6, after turning on the power switch of the copying machine, the heat fixing device 3 is turned on.
This is a temperature detector provided in the heat fixing device 31 to detect that the temperature of the heat fixing device 1 has reached a temperature sufficient to perform heat fixing. Reference numeral 47 denotes a paper ejection detection switch provided near the paper ejection roller 36 in order to detect the copy paper ejected by the paper ejection roller 36.

Note that 47 is a control means for controlling the entire system of the copying machine, and this control means 47 is shown in FIG.
It includes a PU471 and an interface 472,
Signals from the power switch, numeric keypad, print button, memory key, interrupt key, clear key, etc. provided on the operation unit (not shown) and signals from the various detectors mentioned above are given, and based on these signals, the Via the driving means, the driving of the optical device 15, photosensitive drum 21, transport rollers 8, 9, 10, and other rollers described in connection with FIG. 1 is controlled.

Here, 332 is a jam detection switch which is one of the components of the jam detection mechanism which is the main part of the present invention. A specific embodiment of the jam detection mechanism is shown in FIGS. 2-4. In FIG. 2, a frame 10 having a substantially U-shape
The heat roller 3 bridges both side walls 102 and 103 of 1.
3 and a pressure roller 34 are provided in contact with each other.

Then, the side of the tip of the heated roller where the copying paper passes (
On the left side in FIG. 2, an annular guide groove 331 carved to a predetermined depth as shown is formed. More specifically, the position of the guide groove 331 corresponds to the position of the guide groove formed on the photosensitive drum described above.

On the outside of the frame side wall 102 on the side where the guide groove is provided, there is a detection switch 3 for detecting the presence or absence of the winding.
A lever 333 of the detection switch 332 passes through the side wall 102, and its tip is guided by a guide groove 331 of the heat roller 33 as shown in the figure. It has become so. A heater 32 is built into the heat roller 33.

Reference numeral 48 denotes a guide blade provided on the paper ejection side (front) of the heat roller 33 to prevent the paper from being wrapped around the paper, and this guide blade 48 has a shaft 481 rotatably supported on both side walls 102 and 103; Blade 4 connected to shaft 481
82, and a spring 483 provided as a valve device between the blade 482 and the side wall 102.

A guide plate 49 is provided on the bottom of the frame 101 to properly guide the heat-fixed copy paper.
Guide rods 491 are provided on the guide plate 49 at predetermined intervals to ensure that the copy paper is fed forward.

50 is a driving sprocket for rotationally driving the heat roller, and a driven sprocket 1-51 of the pressure roller 34 is engaged with this driving sprocket 50.

Incidentally, FIG. 5 shows a block diagram of the electric circuit of the jam detection mechanism according to the present invention, and FIG. 6 shows a flowchart of the same operation.

The operation of the jam detection mechanism configured as above will be explained below.

(1) First, when the power is turned on, the copying machine starts operating and the heat roller 33 is heated to a predetermined temperature.

Next, the copy paper 4.5 started from the cassette 2.3 is transported to the position of the photosensitive drum 21 by the transport rollers 8.9.10, and is then transferred onto the photosensitive drum 21 by the rotation of the photosensitive drum 21 and the operation of the optical device 15. The latent image of the original 12 formed on the copy 11E4.5 is formed on the copy 11E4.5.

Next, after the latent image is visualized by the developing device 27, the copy paper is guided into the heat fixing device 31, and heated by the heat roller 33.
, is thermally fixed by the pressure roller 34. (Sl) ③ After being ejected from the heat roller, the thermally fixed copy paper is fed forward while being guided by the guide plate 49 in the normal case. In this case, the tip of the lever 333 of the jam detection switch 332 is connected to the guide groove 3 of the heat roller 33.
31, so the detection switch 3
32 does not operate. If for some reason the paper passes through the guide plate 48, the tip of the lever 333 comes into contact with the edge of the copy paper, so the lever 333 rotates and the detection switch/notch 332 is activated. . (S2) ① When the detection switch 332 is activated, this signal is sent to the display device 473 via the CPU 471 and the interface 472 to display that a jam has occurred in the heat roller, and the copying operation is stopped. (S3, S4.
55) (Effect) The jam detection mechanism according to the present invention has a heated roller provided with a guide groove on the side that is always in contact with the copy paper, and the tip of the lever of the detection switch is constantly slid into this guide groove in a stable state. It is configured to be guided by motion.

Therefore, the moment the copy paper is about to wrap around the heated roller,
The edge of the copy paper is caught on the tip of the lever of the detection switch 1, and the tip of the lever is pushed up, so that the detection switch is activated. In addition, since the detection switch is installed outside the side wall of the frame, it is less affected by the heat from the heat roller.Furthermore, the guide groove of the heat roller is on the side that is in constant contact with the copy paper, and as mentioned above, it is not affected by the heat from the heat roller. Since the copy is provided at a position outside the effective range corresponding to the guide groove that guides the peeling claw 29, the copy itself is not affected to the same extent. Further, there is no formation of striped patterns on the copy paper due to contact of the lever with the heat roller.

That is, according to the jam detection mechanism according to the present invention, it is possible to reliably, easily, and immediately detect whether copy paper is wrapped around the heat roller.

[Brief explanation of drawings]

FIG. 1 is a simplified cross-sectional view of an embodiment of a copying machine to which the present invention is applied, FIG. 2 is a perspective view of the jam detection mechanism of the present invention, and FIG. 3 is a view of FIG. 2 from the entry direction. FIG. 4 is a side view of FIG. 2 viewed from direction B, FIG. 5 is a block diagram of the electric circuit of the jam detection mechanism according to the present invention, and FIG. 6 is a flowchart of the operation. Each is shown below. 4.5... Copy paper, 33... Heat roller, 34...
Pressure roller, 331 ... Guide groove, 332 ...
Jam detection switch, 101...Frame.

Claims (1)

[Claims] A jam detection mechanism for a copying machine that transports and copies copy paper based on one side, and includes a heat roller with a guide groove formed on the side that constantly contacts the copy paper, and a frame that pivotally supports the heat roller and pressure roller. and a jam detection switch provided outside the side wall of the frame, and the tip of the lever of the jam detection switch is slidably guided by the guide groove of the heat roller on the paper discharge side of the heat roller. A jam detection mechanism for a copying machine, characterized in that it is equipped with a heat fixing device.