JPS5854060B2 - How to detect paper jam in facsimile receiving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting a paper jam in a facsimile receiving apparatus in which received and recorded paper is conveyed by a suction belt.

Generally, a method for detecting a paper jam is to provide a paper detection sensor in a mechanical part where a paper jam may occur, and to determine that the paper is jammed when the paper reaches the position of the detection sensor. There is a method in which a recording paper detection sensor is provided in a part of the recording paper transport path, and if the recording paper does not reach the detection sensor even after traveling through the route for a certain period of time, it is determined that the recording paper is jammed.

In the former case, detection sensors must be provided in all mechanical parts where there is a possibility of a paper jam, and a very large number of sensors are required.

On the other hand, in the latter case, only one detection sensor is required, which is advantageous in terms of cost.

The present invention belongs to the latter of the above three methods.

In recent facsimile receiving devices, an electrostatic recording method is often adopted because it is easy to print at high speed and the printing is clear.

As is well known, this electrostatic recording method requires the steps of applying a latent image to electrostatic recording paper using a recording device, developing it using a developing device, and then fixing it using a fixing device.

In this case, it is inconvenient to transport the medium during the steps from development to fixing by bringing the medium into contact with the recording surface of the recording paper, such as with a pressure roller, as this will have an adverse effect on the recording device.

Therefore, the recording paper after development is generally transported by a method that does not allow the transport medium to come into contact with the recording surface.

Conveyance using a suction belt is normally used as a method for this purpose.

Conveyance using a suction belt is carried out by reducing the air pressure on one side of the perforated belt using a suction fan or the like, and causing the other side of the perforated belt to suction the non-recording side of the recording paper.

It is desirable that a sensor for detecting a recording paper jam be provided on the recording paper conveyance path by the suction belt.

FIG. 1 shows an example of a recording paper conveying section of a facsimile receiving device that uses a dry electrostatic recording method. A latent image is formed and conveyed to a developing device 5 by a conveying roller 4.

The recording paper 1 developed by the developing device 5 is conveyed by a suction belt 6 to a fixing device 7, and after being fixed by the fixing device 7, the paper is discharged to the outside through a recording paper discharge port 8.

Incidentally, at this time, the recording paper is cut into an appropriate length by a cutter 9.

The above is a description of the recording paper transport section of the electrostatic recording facsimile receiving apparatus. As can be seen from FIG. 1, the mechanism that causes recording paper jams is located upstream of the suction belt 6.

Therefore, if the detection sensor is provided far upstream of the suction belt 6, recording paper jams occurring downstream of the detection sensor will not be detected, which is inconvenient.

On the other hand, if the detection sensor is installed near the discharge port 8, the above-mentioned inconvenience can be eliminated, but if, for example, a recording paper jam occurs due to the conveyance roller 4, by the time the detection sensor detects the recording paper jam, it has already been detected. This means that a large amount of recording paper 1 becomes clogged and causes development.

In such a case, the mechanism section may be damaged by the large amount of recording paper 1 stuck in the mechanism section, which is a serious problem.

Therefore, it can be said that the optimum position for providing the detection sensor is as far upstream as possible, and at the same time there is no risk of recording paper jamming occurring thereafter.

For this reason, the recording paper jam detection sensor is the suction belt 6.
It can be seen that it is desirable to provide this on the recording paper conveyance path.

However, if the detection sensor is provided at this position, the suction belt will get in the way, making detection very difficult.

The present invention has been made based on the above considerations, and provides a detection method that allows a detection sensor to be provided on the conveyance path of the suction belt 6 and that can easily detect a recording paper jam.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a facsimile receiving apparatus in which the present invention is adopted, in which 11 is a step pulse generation circuit for conveying the recording paper 1, and 12 is a step pulse generated by the step pulse generation circuit 11. , a pulse motor drive circuit that drives the pulse motor 13; 14 a counter circuit that starts counting when recording starts and counts the number of step pulses corresponding to the distance between the recorder 3 and the recording paper jam detection sensor 10; 15 a counter circuit; A counter circuit 16 starts counting based on the overflow signal of the circuit 14 and sets a period for monitoring recording paper jams.A counter circuit 16 is a monitoring period set by the counter circuit 15, is gated by the output of the detection sensor 10, and generates a step pulse. 17 is a shaping circuit that amplifies and adjusts the output of the detection sensor 10; 18 is an AND gate; 19 is a counter circuit 16;
20 is a control circuit that controls the facsimile receiving apparatus.

Next, the operation of the facsimile receiving apparatus will be explained.

Generally, prior to the actual exchange of facsimile documents, control signals are exchanged between the facsimile transmitting and receiving apparatuses in order to control them.

When the facsimile original is actually received, the control circuit 20 outputs a start signal to the step pulse generation circuit 11 and the counter circuit 14, whereby the step pulse generation circuit 11 and the counter circuit 14 become operational.

Under the control of the control circuit 20, the step pulse generation circuit 11 generates one step pulse every time recording of the ■ line is completed, and inputs the step pulse to the counter circuit 14 and the pulse motor 1 drive circuit 12, respectively.

The pulse motor drive circuit 12 drives the pulse motor 13 using an input step pulse to convey the recording paper 1.

On the other hand, the counter circuit 14 counts the input step pulses and monitors the start timing of recording paper jam detection, which is performed as follows.

The distance between the recorder 3 and the detection sensor 10 is l, and the pulse motor 1
If the amount of movement of the recording paper due to one step of rotation in 3 is d, the counter 14 is set so that an overflow occurs at a value C that is slightly larger than l/d.

Therefore, when the count value of the counter 14 becomes C and an overflow signal is generated, the leading edge of the recording paper 1 related to reception will be detected by the detection sensor 1 if no recording paper jam has occurred up to that time.
This means that it is at a position slightly past 0.

Then, due to the overflow signal of the counter circuit 14,
Counting circuits 15 and 16 become operational, and detection of a recording paper jam begins.However, counting circuit 15 is set so that an overflow occurs when the counting result becomes t, and therefore t/a. This means that recording paper jams can be detected over a wide distance.

The operation for detecting a paper jam will be described below with reference to FIG.

FIG. 3 is an enlarged view showing the mounting state of the recording paper jam detection sensor 10. The suction belt 21 has a large number of openings 22 for suction at regular intervals P in the direction of movement thereof.

When the recording paper 1 has not reached the position of the detection sensor 10, the light beam of the lamp 23 passes through the opening 22 of the suction belt 21 and reaches the detection sensor 10 intermittently.

Even if the counter 16 is in the operating state, that is, in the recording paper jam detection period, the position of the detection sensor 10 shown in FIG.
If the recording paper 1 has arrived, the opening 22 has reached the recording paper 1.
As a result, the detection sensor 10 does not output any signal.

On the other hand, if the recording paper 1 has not yet arrived, the opening 22 passes in front of the detection sensor 10 at regular intervals P as described above, and a signal is output each time.

The output of the detection sensor 10 is waveform-shaped by the shaping circuit 17 and then input to the AND gate 18, and only when there is an output from the detection sensor, the AND gate 18 outputs the output from the step pulse generation circuit 11. The stabbing pulse is input to the counter circuit 16.

Therefore, if there is no paper jam and the paper 1 is being transported normally, no step pulses will be input to the counter circuit 16 during the paper jam detection period set by the counter circuit 15. .

Conversely, if a paper jam occurs, a step pulse equal to the opening length of the opening 22 of the suction belt 21 is input to the counter circuit 16 each time the opening 22 of the suction belt 21 arrives during the recording paper jam detection period. This will result in

When the counter circuit 15 counts step pulses having a value of t, the counter circuit 15 outputs an overflow signal to the counter circuit 16 and the comparison circuit 19.

In response to this overflow signal, the counter circuit 16 stops counting operation and outputs the counting result to the comparison circuit 19.

The comparator circuit 19 determines the count result of the counter circuit 16 based on the overflow signal of the counter circuit 15, and if it is over a certain value, outputs a recording paper jam detection signal to the control circuit 20, and the control circuit 20 receives this signal. This stops all recording operations and generates an alarm using a buzzer or the like (not shown).

On the other hand, if the comparison circuit 19 determines that the count result of the counter circuit 16 is less than or equal to a certain value, the control circuit 20 continues the normal reception operation from then on until the reception of one sheet of original is completed.

The reason why the comparison circuit 19 makes the judgment below or above a certain value is to prevent erroneous detection due to variations such as slight slippage of the recording paper 1 in the mechanism section, and noise from the fixing device or the like. .

As described above, according to the present invention, since the recording paper jam is detected using the opening formed in the sub-forming belt, the recording paper jam can be easily detected without using any special means.

Moreover, it can be detected at an optimal position.

[Brief explanation of the drawing]

The drawings all show one embodiment of the present invention; FIG. 1 is a schematic configuration diagram of a facsimile receiving apparatus, FIG. 2 is a block diagram, and FIG. 3 is a partial perspective view showing the vicinity of a detection sensor. 1... Recording paper, 10... Detection sensor,
21... Suction belt, 22... Opening.

Claims (1)

[Claims] 1. In a facsimile receiving device that sucks and conveys received and recorded recording paper with a suction belt having openings formed at approximately equal intervals in the direction of movement, A detection sensor is provided at the corresponding part, and when light reaches the detection sensor through the opening, a signal is output, and the signal is counted, and the counting result exceeds a certain value within a set time. 1. A method for detecting a paper jam in a facsimile receiving device, which sometimes includes determining that a paper jam phenomenon has occurred.