JPH0475943A - Paper feed transporting device - Google Patents

Abstract

PURPOSE:To reduce the load on the software of a microprocessor by providing a judging means judging the mode value from a mode counter when the step value from a step counter reaches a preset value and judging whether the paper is correctly fed and transported or not. CONSTITUTION:When a feed motor 13 is turned on and the feed and transport of the paper are started, a step counter 40 starts a counting action. When the paper is transported and detected by a feed sensor 25, a mode counter 43 performs a counting action via on/off signals of the sensor 25, and the outputted mode value is changed. The mode value from the mode counter 43 should be primarily changed when the step value from the step counter 40 reaches the preset value, if it is not changed, a microprocessor 31 judges that an abnormality occurs on the paper feed and transport.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding and transporting device for managing paper feeding and transport in, for example, laser printers, copying machines, and the like.

[Prior Art] For example, in a laser printer, a photoreceptor of a photoreceptor drum is charged in a charging section, information is recorded on the photoreceptor as an electrostatic latent image using a laser beam, and toner is applied to the electrostatic latent image in a developing section. It is designed to be attached. On the other hand, the paper is sent out from a paper feed section equipped with a paper feed cassette, the paper is conveyed via a conveyance path to a transfer section where the toner image from the photoreceptor drum is transferred, and when the paper reaches the transfer section, it is exposed to light. The toner image is transferred from the body drum to the paper.

After the transfer is completed, the paper is fixed in a fixing device and then discharged.

The paper feeding and conveying device used in such laser printers is equipped with a feed sensor in the middle of the conveying path, and the time it takes for the sensor to detect the paper sent out from the paper feeding section is For example, jam detection in a paper feed section or conveyance section is performed by managing the information using a processor and managing the time from when a sensor detects paper to when it no longer detects paper using a microprocessor.

[Problems to be Solved by the Invention] However, in the case where paper feeding and transport state management relies on time management by a microprocessor, there is a problem in that the burden on the microprocessor's software increases accordingly.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a paper feeding and conveying device that can reduce the burden on the software of a microprocessor in managing the paper conveyance state, and can therefore use a microprocessor with low performance. It is.

[Means for Solving the Problems] The present invention provides a feed motor that controls the transport of paper sent from a paper feeder to a transport path, a feed sensor that detects paper passing through a predetermined position on the transport path, and a feed motor. A mode counter that is cleared or released by the on signal of the feed sensor, counts the on/off signals of the feed sensor, and outputs the count value as a mode value, a clock pulse generating means that generates a clock pulse, and a mode counter that turns on the feed motor. The clear state is canceled by the signal and the clock 1 is cleared.
<A step counter that counts clock pulses from the pulse generation means and outputs the count value as a step value, and a mode value from a mode counter when the step value from this step counter reaches a preset predetermined value. A determining means is provided for determining whether or not the paper is being fed and conveyed normally.

[Operation] In the present invention, when the feed motor is turned on and paper feeding and conveyance starts, the step counter starts counting operation. Then, when the paper is conveyed and the paper is detected by the feed sensor, the mode counter performs a counting operation based on the on/off signal of the sensor and changes the mode value to be output.

Therefore, if the step value from the step counter or the mode value from the mode counter when it reaches a predetermined value should change, but there is no change, it is determined that an abnormality has occurred in paper feeding or conveyance.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the present invention will be described as applied to a laser printer.

As shown in FIG. 1, a photosensitive drum 12 whose surface is made of a photoconductive material is disposed approximately at the center of the housing 11. As shown in FIG. This photoreceptor drum 12 is rotationally driven in one direction, that is, clockwise in the figure, by a feed motor 13 composed of a step-sobbing motor, and around the photoreceptor drum 12, photoreceptors are arranged according to the electrophotographic process. A charging unit 14 that charges the photoreceptor of the drum 12, this charging unit 1
A laser scanner unit 15 irradiates the photoconductor charged in step 4 with a laser beam to record information by exposure to form an electrostatic latent image, and toner, which is a developer, is applied to the electrostatic latent image formed on the photoconductor. a developing section 16 that attaches the toner image, and a transfer section 17 that transfers the toner image from the photoreceptor drum 12 to the fed paper.
, a cleaning device 18 that removes residual toner from the photoreceptor drum 12 that has been transferred, and a static eliminator 19 that removes static from the photoreceptor drum 12 that has been transferred are arranged in this order.

A paper feed section 20 is provided on one side of the casing 11, and the paper feed section 20 includes a paper feed roller 22 that can freely approach and separate from the upper surface of the paper 21 stored therein, and a paper feed roller 22. A paper feed solenoid 23 is provided for moving toward and away from the paper.

When the paper feed roller 22, which is rotated by the paper feed solenoid 23, contacts the paper 21 for a predetermined period of time, the paper 2
1 is fed out one by one from the paper feed section 20 at a predetermined timing, and the fed out sheets 21 are conveyed to the position of the transfer section 17 via a conveyance path 24 provided with conveyance rollers (not shown). It looks like this. A feed sensor 25 is provided in the middle of the conveyance path 24.

The paper 21 on which the toner image has been transferred from the photoreceptor drum 12 in the transfer section 17 is supplied to a heat fixing section 26, where it is thermally fixed, and then transferred to the other side of the housing 11 by an ejection roller 27. The paper is discharged out of the housing from a paper discharge port 28 provided in the paper.

FIG. 2 is a block diagram showing the circuit configuration, where 31 is a microprocessor constituting the main body of the control unit, 32 is an input/output port, and these are connected by a pass line 33.

The input/output port 32 includes a paper feed solenoid drive circuit 34 that drives the paper feed solenoid 23, a motor drive circuit 35 that drives the feed motor 13, the laser scanner unit 15, the charging section 14, and the transfer section 17. It includes a high voltage power source 36 that supplies high voltage, a fixing heater 37 of the heat fixing section 26, an operation section 38 provided with a start key, a key for setting the number of prints, etc., a mode counter circuit 39, a step counter 40, and the feed sensor 25. Sensor circuits 42 that control various sensors 41 are connected to each of them.

FIG. 3 shows the main part configuration, and the mode counter circuit 39 includes a mode counter 43, a one-shot timer 44,
and a rising/falling detection circuit 45, and supplies a signal PSO from the sensor circuit 42 to the rising/falling detection circuit 45, which indicates whether or not the foot sensor 25 is detecting the passage of the paper 21. . This signal FS
O is at a high level when the feed sensor 25 does not detect the paper 21;
When it detects 1, it is inverted to low level.

A feed motor on/off signal S is fed from the I10 port 32 to the enable terminal EN of the motor drive circuit 35.
In addition to supplying TI/5TOP, the feed motor on/off signal STI/5TOP is also supplied to clear terminals (low active) CL of the mode counter 43 and step counter 40.

The motor drive circuit 35 also serves as a clock pulse generating means, and uses the stepping clock 5ckl used for phase switching of the feed motor 13 as a clock pulse to the clock input terminal C of the step counter 40.
It is supplied to K.

The mode counter circuit 43 detects the rise and fall of the signal FSO from the sensor circuit 42 using a rise/fall detection circuit 45 and supplies the detection signal to the one-shot timer 44 . This one-shot timer circuit 44 converts the detection signal into a pulse signal (ICKI) of sufficient width and supplies it to the mode counter 43. This mode counter 43 counts the number of input pulse signals MCKI, and uses the count value as a mode value MD.
2.

The microprocessor 31 constitutes a determining means, and I1
A step value SD is read through the 0 port 32, and this step value SD is the first predetermined value ER.

When the mode value from the mode counter 43 reaches "0", the mode value from the mode counter 43 becomes "0".
Check whether the number has changed from "1" to "1", and if it has not changed, it is determined that some kind of failure has occurred in feeding the paper 21 from the paper feed section 20 to the conveyance path 24, and the paper is fed. make an error. Further, if the mode value changes from "0" to "1", it is determined that the paper 21 has been normally fed from the paper feed section 20 to the conveyance path 24.

Furthermore, when the step value SD reaches a second predetermined value ER2, the microprocessor 31 checks whether the mode value from the mode counter 43 has changed from "1" to "2", and checks whether the mode value has changed from "1" to "2". The conveyance path 24 of the paper 21
It is determined that some kind of failure has occurred in the transport, and a transport error is generated.

Further, if the mode value changes from "1" to "2", it is determined that the paper 21 has been conveyed normally.

Note that the first predetermined value ER, is the value when the paper 21 is normally fed and conveyed.
5, and the second predetermined value ER2 is set to the count value of the step counter 40 while the paper 21 is being conveyed normally. step counter 400
It is set to the count value.

In this embodiment having the configuration shown in 2, before printing starts, the phytomotor on/off signal STI/5TOP from the I10 port 32 is off and at a low level, so the mode counter 43 and step counter 4
0 is in the clear state. Therefore, the count value of the mode counter 42 is "0", that is, the mode value MD supplied to the I10 port 32 is "0".

When the start key is operated in this state to start printing, the microprocessor 31 outputs the feed motor on/off signal STI/5TOP via the I10 port 32.
is set to a high-level on signal as shown in FIG. 4(a). As a result, the clear state of the mode counter 43 and the step counter 40 is released, and the motor drive circuit 35 starts rotating the feed motor 13.

At this time, a stepping clock 5ckl is generated from the motor drive circuit 35 as shown in FIG. 4(b) and is supplied to the step counter 40. In this way, the step counter 40 starts a counting operation as shown in FIG. 4(C), and supplies the counted value to the I10 port 32 as a step value SD.

Further, the photosensitive drum 12, the conveyance roller, the paper feed roller 22, etc. begin to rotate. Furthermore, the polygon motor of the laser scanner unit 15 is also activated.

Subsequently, the microprocessor 31 controls the paper feed solenoid drive circuit 34 through the 110 port 32 to operate the paper feed solenoid 23 for a certain period of time. As a result, the paper feed roller 2
2 is sucked for a certain period of time and is brought into contact with the upper surface of the paper 21.

In this way, one sheet of paper 21 is sent from the paper feed section 20 to the conveyance path 24.

When the paper 21 passing through the transport path 24 is detected by the feed sensor 25, the signal FSO from the sensor circuit 42 falls from a high level to a low level, as shown in FIG. 4(d). The falling edge of this signal FSO is detected by the rising/falling detection circuit 45.

Then, a detection signal is supplied from the rising/falling detection circuit 45 to the one-shot timer 44.
4, the pulse signal MCK 1 is converted into a pulse signal MCK 1 having a sufficient width as shown in FIG. 4(e), and is supplied to the mode counter 43. As a result, the mode counter 43 counts up by one and outputs the mode value "1" as shown in FIG. 4(f).

After that, when the paper 21 passes the feed sensor 25, the fourth
As shown in (d) of the figure, the signal FS from the sensor circuit 42
O rises from low level to high level. This signal PS
The rising edge of O is detected by the rising/falling detection circuit 45.

Then, a detection signal is supplied from the rising/falling detection circuit 45 to the one-shot timer 44.
4, the pulse signal MCKI is converted into a pulse signal MCKI having a sufficient width as shown in FIG. 4(e), and is supplied to the mode counter 43.

As a result, the mode counter 43 counts up by one and outputs the mode value "2" as shown in (f') in FIG.

The paper 21 that has passed through the feed sensor 25 is then transferred by the transfer unit 17 and thermally fixed by the thermal fixing unit 26, and then discharged from the paper outlet 28 to the outside of the housing by the discharge roller 27.

and on/off for the feed motor from I10 port 32.
The off signal STI/5TOP is off, that is, (
As shown in a), when the level becomes low, feed motor 1
3 is stopped, and the generation of the stepping clock 5ckl is stopped as shown in FIG. 4(b). Also, the mode counter 43 and step counter 40 are cleared, and the mode value of the mode counter 43 becomes "0".

Therefore, if the microprocessor 31 reads the mode value HD from the mode counter 43 when the step value SD from the step counter 40 reaches the first predetermined value ER, the current paper 21 is fed and transported without any abnormality. You can easily find out whether the Furthermore, by reading the mode value HD from the mode counter 43 when the step value SD from the step counter 40 reaches the second predetermined value ER2, it is possible to easily know whether or not the paper 21 is being transported without any abnormality thereafter. I can do it.

That is, as shown in FIG. 5, the microprocessor 31 enters a state in which paper is continuously fed if the mode value HD is "0";
i.e. on/off signal for feed motor STI/5T
It is determined whether OP is an on signal or an off signal, and if it is an off signal, it is determined that the operating state (A), that is, a state in which paper is not being conveyed at all.

Also, feed motor on/off signal STI/5TOP
If it is an ON signal, it is determined that the operation state (B) is in effect, that is, a state in which the paper feed roller 22, the conveyance roller, and even the polygon motor in the laser scanner unit 15 start to start and paper is fed. In this state, wait until the step value SD of the step counter 40 reaches the first predetermined value ER, and wait until the step value SD reaches the first predetermined value ER,
When reaching , the mode value HD at that time is read. As a result, if the mode value HD is "1", it is determined that paper feeding was performed normally. However, if the mode value MD remains "0", it is determined that some abnormality has occurred in paper feeding, and a paper feeding error is determined.

Also, when the mode value MD is "1", the operating state (C)
That is, it is determined that the feed sensor 25 detects that the paper 21 is passing and continues the paper conveyance control. In this state, it waits for the step value SD of the step counter 40 to reach the second predetermined value ER2, and when the step value SD reaches the second predetermined value ER2, the mode value MD at that time is read. As a result, the mode value HD is "2"
If it is, it is determined that the transport is being carried out normally.

However, if the mode value MD remains "1", it is determined that some abnormality has occurred in the conveyance of the paper 21, and a conveyance error is determined.

Furthermore, when the mode value MD is r2J, the operating state (D)
That is, it is determined that the paper 21 will pass through the feed sensor 25 and the conveyance control will soon end.

In this way, the microprocessor 31 is simply I10.
reads the step value SD of the step counter 40 and the mode value MD of the mode counter 43 through the port 32;
If the mode value HD remains rOJ when the step value SD reaches the first predetermined value ER, a paper feed abnormality is determined and an error occurs, and when the step value SD reaches the second predetermined value ER2. If the mode value MD remains "1", it is determined that there is an abnormality in paper conveyance and an error occurs, so the software operates an internal timer while the feed sensor 25 detects the conveyance of the paper 21, as in the past. You don't have to manage your time. Therefore, the software burden on the microprocessor 31 can be reduced.

Therefore, even if the paper conveyance speed increases for high-speed printing, the microprocessor 31 can sufficiently cope with the increase.
Also, the microprocessor can be changed from 8 bit type to 4 bit type.
Even if you switch to the IT type, you can still have sufficient control. In other words, it is also possible to use a microprocessor with low performance.

In the above embodiment, the motor drive circuit also serves as the clock pulse generation means, but the invention is not necessarily limited to this, and a clock pulse generation means may be provided separately.

In addition, although each of the above-mentioned embodiments has been described in which the present invention is applied to a laser printer, it is needless to say that the present invention is not necessarily limited to this.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reduce the burden on the software of the microprocessor in managing the conveyance state of paper, and therefore it is possible to use a microprocessor with low performance. It is possible to provide a paper conveyance device.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is a schematic configuration diagram of a laser printer, Fig. 2 is an overall block diagram, Fig. 3 is a block diagram of main parts, and Fig. 4 is a block diagram of a laser printer. FIG. 5 is a timing chart showing the operation timing of each part. FIG. 5 is a flowchart showing the state judgment process during sheet conveyance by the microprocessor. DESCRIPTION OF SYMBOLS 13... Feed motor, 21... Paper, 25... Feed sensor, 31... Microprocessor, 35... Motor drive circuit, 40... Step counter, 43... Mode counter. Ward 1

Claims (1)

[Claims] A feed motor controls the conveyance of the paper sent from the paper feed unit to the conveyance path, a feed sensor detects the paper passing through a predetermined position on the conveyance path, and the clear state is canceled by the ON signal of the feed motor and the a mode counter that counts on and off signals of the feed sensor and outputs the count value as a mode value; a clock pulse generating means that generates a clock pulse; and a clear state is released by the on signal of the feed motor and the clock A step counter that counts clock pulses from the pulse generating means and outputs the count value as a step value, and a mode value that is output from the mode counter when the step value from the step counter reaches a predetermined value. 1. A paper feeding and conveying device characterized in that a determining means is provided for determining whether or not paper is being normally fed and conveyed.