JPS6038709B2 - Paper jam detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting paper jams that occur in a recording paper feeding path of a facsimile machine.

Conventionally, consideration has been taken to prevent paper jams from occurring in the paper transport path, but paper jams due to failure of a part of the device, malfunction of an electric circuit, etc. cannot be avoided.

When this paper jam occurs, it becomes impossible to feed the paper thereafter unless the jammed paper is removed, and it is recognized that how to detect this paper jam as quickly as possible is an important problem.
A model diagram of a conventional, well-known paper jam detection device is shown in FIG.

Generally, a first switch 2 for detecting paper feed is provided in the paper feed section 1, and a second switch 4 is provided after passing through various processing devices 3. is moved from "L" to "H" by the starting edge of the paper, and from "H" to "L" by the ending edge of the paper. The paper continues,
It enters the processing device 3 and is eventually discharged by similarly operating the second switch 4 on the downstream side of the processing device 3. This conventional paper jam detection device will be described with reference to a schematic timing chart shown in FIG. 2. After the first switch 2 is activated by the end of the paper tray, the first timer starts counting time. Eventually, the second switch 4 is operated by the paper terminal, and after a short delay, the first timer finishes counting and the output is reversed.
In Fig. 2, when the output c of the first timer is "H", if the output b of the second switch 4 is "H", the output e of the jam gate remains "L", and therefore there is no jam. It is configured. Therefore, if the output b of the second switch 4 is "L" at this time, the output e of the jam gate becomes "H", and it is determined that a paper jam has occurred in the processing device 3 at the beginning of the paper. Furthermore, after the end of the paper passes through the first switch 2 and the current power a becomes "L", the second timer starts timing, and when the end of the paper passes through the second switch 4, the output b becomes "L", and after a short delay, the second timer finishes counting and the output d becomes "rH". In FIG. 2, when the output d is "H" and the output b is "L", the output e of the jam gate remains "L", so there is no jam. Therefore, if the output b is "Hj" at this time, the output of the jam gate becomes "H", and it can be determined that the trailing edge of the paper remains in the second switch 4 and has not passed through. Now, in this conventional jam detection device, it is necessary to provide a dedicated timer for each time the starting edge of the paper enters the jam detection switch, that is, the second switch 4, and the passing of the trailing edge of the paper. In the facsimile machine, the time for the leading edge of the recording paper to reach the second switch 4 is not just a fixed time; the distance the recording paper is fed during recording depends on the total number of variable pulses during the pulse of the pulse motor. Since the recording paper is fed by two types of feeding means: one is fed to the intermediate point, and after the end of the recording paper is cut off, it is ejected from the outside of the running motor at a constant rate. Therefore, the above-mentioned counter measures the number of pulses applied to the pulse motor. Counting and fixed-time counting must be used simultaneously.

It has a function of continuous transmission and reception of multiple sheets, so-called transportation function, and the feeding of the next page is started before the trailing edge of the previous page is cut and passes the jam detection switch, and the feeding of the next page is started between the trailing edge of the previous page and the starting edge of the next page. In some cases, the page is fed with a gap of only about 0.9 stages, and the so-called inter-page gap is short. As a result, new malfunctions are likely to occur due to adjustment errors. The present invention has been made to eliminate such drawbacks of the conventional art, and embodiments thereof will be described below with reference to the drawings.

FIG. 3 shows a conceptual diagram of a facsimile machine that is the basis of the present invention.

11 is a roll of electrostatic recording paper (hereinafter referred to as recording paper); 12
1 is a recording head, and 13 is a pressure roller.

Immediately downstream of the recording head 12, a drive roller 14 driven by a pulse motor (not shown) is installed to intermittently drive the recording paper according to image information, and immediately downstream of this is a drive roller 14 that drives the recording paper 11 intermittently. A cutter 15 is provided for cutting the terminal end.

The recording paper on which the electrostatic latent image has been applied by the recording head 12 is fed through a developing device 18 and a fixing device 19 provided between two sets of feed rollers 16 and 17, where the toner is adhered and fixed and a visible image is formed. Then, operate the jam detection switch 21 (hereinafter referred to as the switch) to eject the jam. The liquid is discharged from the apparatus by the roller 22. 2
This is a Kawama vacuum suction device to prevent the recording paper 11 from falling into the fixing device 19 during fixing.

Note that the circumferential speeds of the running rollers 16 and 17 are set slightly higher than the maximum average circumferential speed of the drive roller 14 in order to prevent sagging of the recording paper. In Fig. 3, a conventional jam detection device (
The first switch 2 provided in FIG. 1) is omitted.

This is because the cutting signal of the cutter 15 itself is effectively used as a jam detection means. FIG. 4 shows a block diagram of a jam detection device according to an embodiment of the present invention, and FIG. 5 shows a timing chart. The following description will be made assuming that three originals are received in succession and the last one jams in the developing device 18 or the fixing device 19.

Recording of the first sheet is started, development and fixing processing is carried out without any problems, and eventually the switch 21 is operated by the starting edge of the first sheet of recording paper 11, and the switch signal g rises as shown in FIG. 31, and this output h is held at "L". The recording of the first sheet is then completed, and then the recording of the second sheet is started, and eventually the end of the first sheet reaches the cutter 15 and is cut.

Thereafter, the first sheet is released from the drive roller restraint and is driven at a constant speed by the feed rollers 16 and 17. The cutter signal f at this time is held in the cutter memory 32, and the output 1 of this cutter memory 32 is set to "L". When the output of the cutter memory 32 becomes "L", the detection timer 34 starts timing.
Eventually, the detection timer 34 completes timing, and this output j is
Set to "H". On the other hand, the jam gate 35 is constituted by a two-input AND of the outputs j and h, and its output k becomes "H" only when both inputs are "H". In this case, the output h is "L"
Therefore, the output k is "L". If the output k is set to "H" as a jam, this means that the end of the first sheet of recording paper has safely reached the switch 21. Incidentally, FIG. 5 shows the case of paper, which is relatively short, and shows the case where the end of the page is cut off before the start of the paper reaches the switch 21. After a predetermined period of time after being triggered by the output i, the reset timer 36 completes timing and emits the output i.

The reset gate 37 outputs this output i and the jam gate output k.
consists of two inputs, the output k is inverted by the inverter 38, and in the above case, the output k becomes "H", so the output i becomes "
When the output m of the set gate 37 becomes "H", the start end memory 31 and the cutter memory 32 are reset. That is, the reset gate 37 is the jam gate 3
5 is not a jam, the reset timer 36 can issue the output m after completion of timing.

Subsequently, the terminal end of the first sheet passes through switch 21,
The switch signal g becomes "L" as shown in FIG. 52.

There is no need to memorize the fact that the signal becomes "L" at point 52 in any other element. Next, the female end of the second recording paper operates the switch 21 in the same manner.

At this time, since the end of the first sheet has passed through the switch 21, the switch signal g rises again at the point 53 in FIG. Similarly, the rising edge 53 of this output g is stored in the starting memory 3.
2 is detected, and the same process as the first sheet is followed, no jam occurs, and the switch signal returns to "L" at point 54.
Next, it is assumed that the third sheet of recording paper has jammed in the developing/fixing device.

At this time, the switch signal g does not rise at the point 55 when it should have risen, so the starting edge memory 31 remains at "H", the detection timer 34 completes timing, and this output i becomes "H".
When this happens, the output of the jam gate 35 becomes "H",
Jam occurrence can be detected. In the event of a jam, the power k becomes "H" as described above, so k, which is also one input of the reset gate 37, becomes "L", so even if the output i of the reset timer 36 becomes "H" , reset gate 37
The output m cannot become "H", so the reset operation is blocked, and once the jam gate 35 detects a jam, the output k is kept at "H". If this power k is used to stop the operations of the recording paper feeding, developing and fixing devices and to emit an alarm sound, an ideal jam detection device can be obtained. Up to this point, a case has been described in which the leading edge of the recording paper jams on the upstream side of the switch and does not reach the switch 21.

Next, if the starting end has arrived but the trailing end remains on the upstream side,
Therefore, a case will be described in which the switch 21 remains in the "H" state.

In this case, the output g of the switch in FIG. H)
Since there is no rising edge, the output h of the start end memory 31 is “
Without switching from “H” to “L”, the detection timer output i
When becomes "H" and performs detection, the output k of the jam gate
becomes "H" and the occurrence of a jam can be detected. As described above, the present invention detects the entry of the starting edge of the recording paper into the switch 21 by capturing the rising edge of the switch signal, memorizes this, and confirms the presence or absence of this rising edge after a predetermined period of time after the final cutting of the recording paper. After it has been used, this memory is reset, and when the leading edge of the next recording sheet enters, both the passing of the trailing edge of the former recording sheet and the intrusion of the female end of the next recording sheet are detected. Unlike the method described above, there is no need to independently detect each female terminal and terminal end, and therefore, even if the inter-page gap described above is short, it is only necessary to accurately set one detection timer.

Furthermore, the start edge detection does not require a composite timer that counts the pulses applied to the pulse motor and switches to a fixed timer halfway, unlike the conventional method.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a feeding system to explain a conventional jam detection device, Fig. 2 is a timing chart showing the operation of the conventional device shown in Fig. 1, and Fig. 3 is a conceptual diagram showing an embodiment of the present invention. 4 is a block diagram of an embodiment of the jam detection device based on the present invention, and FIG. 5 is a dimming chart showing the operation of the jam detection device based on the present invention. In the figure, 1 is a paper feeding section, 2 is a first switch, 3 is a processing device, 4 is a second switch, 11 is a roll of recording paper, 12
1 is a recording head, 14 is a drive roller, 15 is a cutter, 1
6 and 17 are feeding loafs, 18 is a developing machine, 19 is a fixing device,
21 is a switch, 31 is a start end memory, 32 is a cutter memory, 36 is a reset timer, 34 is a detection timer, 3
5 indicates a jam gate. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a facsimile device that forms an electrostatic latent image on recording paper, cuts the starting and ending edges of the recording paper with a cutter, and then performs development and fixing, a facsimile device is installed downstream of the developing and fixing device and is operated by the recording paper. a start-edge memory that memorizes that the start end of the recording paper has arrived due to the switch operation; a detection timer that is triggered by a cutter signal generated when the end of the recording paper is cut and generates an output after a predetermined time; It is equipped with a jam gate that receives the output of the start-end memory and the output of the detection timer as input, and a reset timer that is triggered by the output of the detection timer and generates an output after a fixed period of time.When the detection timer is output, the start-end memory is in the storage state. If so, it is considered normal,
Subsequently, the start end memory and detection timer are reset by the output of the reset timer, and if the start end memory is in a non-memory state when the detection timer is output, it is assumed that there is a jam, and the output of the reset timer is reset. A paper jam detection device characterized in that it is configured to prevent a paper jam.