JPS63246548A - Condition detecting device for power load - Google Patents

Abstract

PURPOSE:To detect loaded condition during operation of an apparatus by providing the first and second sensors respectively adapted to detect one projecting portion and plural projecting portions in a laser printer or the like. CONSTITUTION:When a load side pulley 14 is driven to rotate by a driving motor 13, simultaneously a timing pulley 7 of a detecting unit 1 is rotated by a timing belt 10. When a projecting portion 3 of the timing pulley is detected by the first magnetic sensor 8, a timer 25 having time period corresponding to two rotations is started through an amplifier 22. Within the time period of the timer, the second magnetic sensor 9 detects plural, for example, twenty projecting portions 5A, 5B... per one rotation, a value counted by a counter 26 through an amplifier 24 is compared with a reference value of a setting circuit 28 by a comparator 27, and the comparison value, that is, loaded condition is displayed in a display circuit 29. Thus, the loaded condition can be detected while an apparatus is operated.

Description

[Detailed Description of the Invention] [Summary] A device that detects the state of a load such as a pulley that receives the rotational force of a drive motor via a timing belt in the operating state of the device, and is detachable from the timing belt. a timing pulley, first and second sensors for one and a plurality of protrusions formed on the upper and lower parts of the outer periphery of the timing pulley; The present invention includes a signal processing unit that compares the output value of the second sensor with a set reference value, and when the comparison does not match, it is possible to detect an abnormal load state of the load-side pulley.

[Industrial application field]

The present invention relates to a power load state detection device that is effective when applied to inspecting a motor rotation drive system of a laser printer or the like.

The print drum of a laser printer is rotated by the driving force of a drive motor being transmitted via a timing belt and a pulley.

In such a drum drive system, the rotation of the load pulley depends on conditions such as the tension of the timing belt that connects the load pulley and the drive motor, and the lack of oil that serves as a lubricant for the drive motor. When starting, the initial speed often fluctuates, making it difficult to drive smoothly. Therefore, there are problems such as the pitch of characters printed on the recording paper being shifted and the printing quality being degraded. For this reason, there is a need for a means for accurately detecting whether or not the drive motor and the pulley on the load side are driving normally while the device is being driven.

[Conventional technology]

Conventionally, in order to detect problems such as printing pitch deviations, the general method used was to test solid black printing on recording paper and have an inspector visually inspect the pitch between the prints. ing.

[Problem that the invention seeks to solve]

However, such an inspection method cannot be carried out while the device is in operation, and the conditions are different from when the device is actually in operation, making it less reliable. Furthermore, such an inspection method consumes a large amount of toner, resulting in high inspection costs.

The object of the present invention is to eliminate the above-mentioned problems and provide a device that can easily detect the load state of the load-side pulley with respect to the drive motor while the device is in operation.

[Means and operations for solving the problems] In order to solve the above problems, the present invention provides a timing belt that transmits the rotational power of a drive motor, which can be attached to and removed from the timing belt by sandwiching it between the guide rollers, and which has a protruding part. a timing pulley having an upper outer circumferential portion having one protruding portion and a lower outer circumferential portion having a plurality of protruding portions; and a first timing pulley that detects the one protruding portion in proximity to the timing pulley that is coupled to the timing belt and rotates. a detection unit comprising a sensor and a second sensor that detects the plurality of protrusions; a timer that generates a reference timing signal having a predetermined time width based on the detection signal of the first sensor; a counter that counts the detection signal of the second sensor based on a timing signal;
The total count value is compared with a preset reference value, and when the comparison is a failure, the load on the drive motor is detected to be in a normal state, and when the comparison rate is a failure, the load is detected to be in an abnormal state. .

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a detection unit of a power load state detection device according to the present invention, and FIG. 2 is a perspective view of a timing pulley and a detection sensor in the detection unit.

As shown in FIGS. 1 and 2, the detection unit 1 has a U-shaped housing 2, an upper outer peripheral portion 4 with one protrusion 3 formed thereon, and 20 protrusions 5A, 5B, 5C, An iron timing pulley 7 consisting of a lower outer peripheral portion 6 formed with... is rotatably installed.

Incidentally, the pitch between the protrusions of the lower outer circumferential portion 6 corresponds to the pitch of the drive teeth of the timing belt, which will be described later, so that the two can be connected in a tooth-shaped meshing manner.

The housing base portion located close to the timing pulley 7 has a
A first magnetic sensor 8 that winds a coil 8B around a permanent magnet 8A and detects the protrusion 3 of the upper outer peripheral portion 4, and a permanent magnet 9.
A coil 9B is wound around A, and a second magnetic sensor 9 is fixed to detect the 20 protrusions 5A, 5B, 5G, . A guide roller 11 made of sponge rubber is rotatably installed with a gap equivalent to the thickness of .

This timing belt 10 is made of a non-slip material such as urethane rubber, and is also connected to the timing pulley 7 during device inspection, but normally it is used as a timing belt for rotationally driving the printing drum of a laser printer as described above. As shown in FIG. 3, the drive motor 13 and the load side boolean 1114 are connected.

The guide roller 11 installed close to the timing booth I77 is attached to the housing 2 by a pin 12, and can be easily attached to and detached from the housing 2 by removing this pin 12.

Therefore, with the guide roller 11 removed, the lower outer peripheral portion 6 of the timing pulley 7 in the detection unit 1 is
As shown in FIGS. 1 and 3, it can be easily connected to the drive teeth of the timing belt 10 that connects the drive motor 13 and the load-side pulley 14. In this combined state, the guide roller 11
When the timing belt 10 is attached to the housing 2, the timing belt 10 is sandwiched between the timing pulley 7 and the guide roller 11, and is completely connected to the lower outer peripheral portion 6 of the timing boot IJII.

When the drive motor 13 starts to drive in this state, the load side boot 4 rotates and at the same time the timing pulley 7 of the detection unit 1 attached to the timing belt 10
It also rotates.

By rotationally driving this timing boolean IJ 7, the protruding portion 3 of the timing pulley 7 and the protruding portions 5A and 5B.

5C... constitute a magnetic circuit together with the respective magnetic sensors 8 and 9. Therefore, each magnetic sensor 8, 9 and the protrusion 3.5A of the timing pulley 7
, 5B, 5C... are close to each other or separated,
The air gap distance between them changes, and the strength of the magnetic field detected by the magnetic sensors 8 and 9 changes due to the change in this distance.

Based on the detection of fluctuations in the strength of this magnetic field, the timing pulley 7
Every time the magnetic sensor 8 rotates once, the magnetic sensor 8 generates one pulse signal,
Each magnetic sensor 9 outputs 20 pulse signals. Each detected pulse signal is then processed by the signal processing unit 1.
The signal is processed in step 5.

FIG. 4 shows a block diagram of this signal processing unit 15, and FIG. 5 shows an output signal waveform diagram of the processing circuit.

As shown in FIG. 4, the pulse signal 21 output from the magnetic sensor 8 is amplified by the amplifier 22 for a time tl.

Start clock signals 31A, 31 with an interval of t2
It becomes B. This time t1 corresponds to the time required for the timing pulley 7 to rotate once at the time of detection.

On the other hand, the pulse signal 23 outputted from the magnetic sensor 9 is amplified by the amplifier 24 and becomes a dead clock signal 33^,
It becomes 33B.

The timer 25 is activated by the start clock signals 31A and 31B.
is activated to output a reference timing signal 32 with a pulse width corresponding to time t. The pulse width t of this reference timing signal 32 is set in advance so as to match the time required for two rotations of the timing pulley when the sensing load side pulley is rotating normally via the timing pulse 10. The reference timing signal 32 output from the timer 25 is input to the counter 26, and a counting operation is executed within the pulse width thereof. The counter 26 inputs and counts the dead clock signals 33A and 33B,
The counted value is supplied to one input terminal of the digital comparator 27. A reference value setting circuit 28 is connected to the other input terminal of the comparator 27. The setting circuit 2
The reference value of 8 is the numerical value "4" corresponding to the number of pulse signals output from the magnetic sensor 9 per two rotations of the timing pulley 7.
0". The digital comparator 27
compares such a reference value and the count value, and the comparison value is displayed by the display circuit 29.

A case will be described in which the load state of the load-side pulley with respect to the drive motor is detected using such a signal processing unit 16.

In FIG. 5, section A shows a normal loaded state of the load pulley, and section B shows an overloaded state. That is, in section A where the load is normal, two pulse signals 31^ are output from the magnetic sensor 8 and 40 pulse signals are output from the magnetic sensor 9 within the reference timing set by the timer 25. There is.

Therefore, the counter 26 counts 40 dead clock signals 33A, and the digital comparator 27 outputs the counted value "40" and the reference value "40" from the reference value setting circuit 28.
When a match is detected, the display circuit 29 displays the numerical value "01".

However, in section B where the load is overloaded, the timing pulley 7 rotates slowly, so it cannot rotate twice within the reference timing set by the timer 25, and one pulse signal from the magnetic sensor 8, 9 outputs only 36 pulse signals.

Therefore, the counter 26 counts a value of "36", the digital comparator 27 outputs a difference value of "-4", and the display circuit 29 displays a value of "-4" to indicate an overload condition.

Conversely, if the number of pulse signals from the magnetic sensor 9 is greater than the reference value "40", a positive value is displayed on the display circuit 29, indicating that the load is too small.

Further, when the pulse waveform value of the detection signal 33A and the pulse voltage waveform value of the detection signal 33B are equal to the reference value t,
The number "0" is displayed on the display circuit, and in this case, the load is normal.

In this way, while the apparatus is in operation, the state of the load on the drive motor 13 can be easily detected, that is, it is possible to easily determine whether the driving state of the print drum is correct or not.

In this embodiment, magnetic means were used to detect the protrusion of the timing pulley, but optical means may also be applied. Specifically, the protruding part of the timing pulley is polished more precisely than the parts other than the protruding part to make it easier to reflect light, and the light emitting element and light receiving element are placed at a predetermined angle with respect to the surface of this protruding part. Each is placed in a housing.

〔Effect of the invention〕

As described above, according to the present invention, the condition of the load side connected to the drive motor by the timing belt can be detected while the device is in operation, so it is useful for inspecting the printing drum drive mechanism of a laser printer, etc. It has practical effects when applied.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example configuration of a detection unit of the present invention, FIG. 2 is an explanatory diagram of main parts of the detection unit, FIG. 3 is an explanatory diagram of the detection unit attached to an electronic device, FIG. 4 is a block diagram showing an example of the detection signal processing unit of the present invention, and FIG. 5 is an output signal waveform diagram of the signal processing circuit. In the figure, 1 is the detection unit, 2 is the housing, 3, 5A, 5B, 5C.
... is a protrusion, 4 is an upper outer periphery, 6 is a lower outer periphery, 7 is a timing pulley, 8 is a first magnetic sensor, 8^, 9A
are permanent magnets, 8B and 9B are coils, 9 is a second magnetic sensor, 10 is a timing belt, 11 is a guide roller, 1
2 is a pin, 13 is a drive motor, 14 is a load side pulley, 1
5 is a signal processing circuit, 22.24 is an amplifier, 25 is a timer, 26 is a counter, 27 is a digital comparator, 28
The present invention is shown in Figure 1 and Figure 2, along with the historical unit.

Claims (1)

[Claims] The timing belt (10) that transmits the rotational power of the drive motor (13) has an upper outer circumferential portion (4) that is removable and sandwiched between the guide roller (11) and has one protrusion (3), and a protrusion. a timing pulley (7) having a lower outer peripheral part (6) having a plurality of parts (5A, 5B, 5C...); and a timing pulley (7) that is connected to the timing belt and rotates. A first sensor (8) that detects one protrusion (3) and a second sensor (9) that detects the plurality of protrusions (5A, 5B, 5C...). a detection unit, a timer (25) that generates a reference timing signal having a predetermined time width based on the detection signal of the first sensor, and a counter that counts the detection signal of the second sensor (9) based on the reference timing signal. (26), and the total count value and a preset reference value, and when the comparison matches, the load (14) to the drive motor (13) is in a normal state, and when the comparison does not match, the load (14) is abnormal. 1. A power load state detection device comprising: means (27 to 29) for detecting a state.