JPH087517B2 - Dry electrophotographic device - Google Patents

Description

The present invention relates to a dry electronic device such as a copying machine or a laser printer.

[Prior Art] Generally, the structure of a dry electrophotographic apparatus is configured as shown in FIG. That is, reference numeral 1 denotes a housing, and the housing 1 accommodates an exposure unit 2 including a laser scanner unit, an LED array, and the like, and a photoconductor 3 including a photoconductive material. The photoconductor 3 has, for example, a drum shape, and a charging unit 4 including a corona discharger and the like around the photoconductor 3, a developing unit 5 having a replenishment toner box containing toner inside, a transfer unit 6, and the photoconductor 3
The cleaning unit 7 that wipes off the toner remaining on the printer and collects it in the waste toner box, LED, incandescent lamp, etc.
A static elimination unit 8 is provided for uniformly eliminating static electricity on the surface of the.

9 is a paper feed unit, from which the pickup roller
A sheet as a material to be transferred is supplied to the photoconductor 3 by 10. This paper is transferred to the photoconductor 3 at the transfer unit 6.
The toner image formed on is transferred, and the transferred toner image is fixed by the fixing unit 11 and then discharged by the discharge roller 12 above the housing 1.

The surface of the photoconductor 3 is uniformly charged by the charging unit 4 while being rotated, and an electrostatic latent image of image information is formed on the charged surface by the exposure unit 2. Then, toner is attached to the electrostatic latent image in the developing unit 5 to form a toner image, and then the toner image is transferred to a sheet in the transfer unit 6.

Reference numeral 13 is a motor for driving the conveying system, and 14 is a fan for releasing heat in the housing 1 to the outside and used for removing ozone and toner through the filter.

Reference numeral 15 is a DC power source having a signal system power source and a drive system power source, and 16 is the DC power source by detecting the opening of the cover forming a part of the housing 1 by removing jammed paper or replenishing toner. It is an interlock switch that shuts off the power supply of the drive system inside. The drive system power source is a power source for the exposure unit 2, charging unit 4, developing unit 5, transfer unit 6, charge eliminating unit 8, fixing unit 11, motor 13, and the like.

The circuit configuration is as shown in FIG.
21 is a CPU that constitutes the main body of the control unit, 22 is a ROM that stores program data for the CPU 21 to control each unit, 2
3 is a RAM that stores various setting data that is input externally, 24
Is an I / O port. The CPU 21, ROM 22, RAM 23, and I / O port 24 are electrically connected via a bus line 25.

The I / O port 24 has a motor drive circuit 26 for driving and controlling the motor 13, a high voltage power supply circuit 27 for supplying a high voltage to the exposure unit 2, the charging unit 4 and the transfer unit 6, a toner empty sensor 28 and a toner. Toner sensor circuits 30 that drive and control the fluid sensor 29 are connected to each other.

The toner empty sensor 28 is housed in the replenishing toner box of the developing section 5 and detects the toner shortage in the box. The toner-flux sensor 29 is housed in the toner discharge box of the cleaning unit 7 and detects when the toner discharge inside the box is full.

Further, the I / O port 24 has an operation panel 31 provided with a display for displaying various statuses, a key switch for setting data, a paper sensor 32 for detecting a paper supply state and a conveyance state, and a host computer. An interface 33 and the like for exchanging data is connected.

The DC power source 15 has two power sources, a + 5V signal system power source and a + 24V drive system power source.
1, ROM22, RAM23, I / O port 24, and drive system power is supplied to the motor drive circuit 26, exposure unit 2, high-voltage power supply circuit 27, fan 14, etc. via the interlock switch 16. .

Therefore, if the cover of the housing 1 is opened to remove jammed paper, replenish toner, or remove discharged toner, the interlock switch 16 is turned off, and the motor drive circuit 26, the exposure unit 2, the high-voltage power supply circuit 27, The supply of drive system power to the fan 14 and the like is stopped to ensure safety.

By the way, conventionally, the toner empty sensor 28 described above is used.
The toner blew sensor 29 is equipped with a piezoelectric buzzer, and when a toner shortage or exhaust toner full is detected, the piezoelectric buzzer vibrates, and the vibration is received by the piezoelectric element and converted into a voltage signal and supplied to the toner sensor circuit 30. Was there. The power supply of the toner sensor circuit 30 is such that the signal system power supply is supplied via the I / O port 24.

To give a concrete example of the configuration, as shown in FIG.
5V signal system power supply is used as a power supply, voltage signals from sensors 28 and 29 are amplified by Darlington-connected transistors 41 and 42, which is then AC-coupled by capacitor 43, and then DC level by integrating circuit consisting of resistor 44 and capacitor 45. I / O port 24, which is converted into a binary signal and output from the comparator 46 and then inverted by the transistor 49. It was supposed to be output to.

In this circuit, when the sensor 28 detects a shortage of toner in the replenishment toner box of the developing unit 5 or the sensor 29 detects that toner accumulated in the toner discharge box of the cleaning unit 7 is full, the piezoelectric buzzer vibrates and The piezoelectric element receives the voltage signal and outputs it. Then, this voltage signal is input to the base of the transistor 41, and the signal is amplified by the transistors 41 and 42. Then, the amplified signal is supplied to the integrating circuit composed of the resistor 44 and the capacitor 45 via the capacitor 43, the DC level generated between both ends of the capacitor 45 becomes high, and the comparator 46 outputs a high level signal. Then, the transistor 49 is turned on, and a low-level detection signal is supplied to the I / O port 24 from the collector of the transistor 49. In this way, the CPU 21 can grasp the toner shortage in the supply toner box of the developing unit 5 and the full state of the toner accumulated in the discharge toner box of the cleaning unit 7.

[Problems to be Solved by the Invention] However, since the drive circuit of the conventional toner sensor uses only the signal system power supply, for example, when the cover is opened for toner replenishment or toner discharge, the drive system power supply is an interlock switch. Although the signal system power supply is not cut off by the operation of 16, the toner sensor circuit 30 is continuously supplied with power. For this reason, the piezoelectric buzzer of the sensor continues to vibrate, and several KH from the piezoelectric buzzer.
The oscillating sound of z will continue to be emitted.

This oscillating sound is normally hardly noticed when the cover is closed and the fan 13 and other parts are operating, but when the cover is open, the fan 13 and other parts are also stopped. Therefore, there is a problem that some people feel uncomfortable because of the sound emitted by the voltage buzzer.

Therefore, when the cover is opened, the drive system power supply as well as the signal system power supply should be shut off.
Since the data set in the RAM23 and the setting contents of the intelligent function are destroyed, the cover must be reset every time the cover is opened, which is not suitable for practical use.

Therefore, according to the present invention, when the cover is opened, only the drive system power supply is shut off, and further, the power supply to the toner sensor can be shut off by shutting off the drive system power supply, thereby preventing an unpleasant sound from the piezoelectric buzzer when the cover is opened. The present invention is intended to provide a dry electrophotographic apparatus that can be used.

[Means for Solving the Problems] The present invention provides a signal system power supply and a drive system power supply as power supplies.
A photoconductor, a charging unit, an exposing unit, a developing unit, a transfer unit, a charge eliminating unit, which is provided with a system and is connected to the drive system power source based on a control signal from the control unit connected to the signal system power source and is housed in the housing. The fixing unit is controlled, and the charging unit charges the photoconductor, and then the exposure unit exposes image information to form an electrostatic latent image on the photoconductor. Toner is attached to the electrostatic latent image on the body to form a toner image, then the transfer unit transfers the toner image to the transfer material, and then the cleaning unit removes the toner remaining on the photosensitive member. The post-electrification section eliminates the charge on the surface of the photoconductor, the fixing section fixes the toner image transferred to the transfer material, and then discharges the transfer material, and forms a part of the housing. Dry type electronic that shuts off only the drive system power by detecting the opening of the cover with the interlock switch In a true device, a piezoelectric buzzer and a piezoelectric element that generates a voltage in response to vibration of the piezoelectric buzzer, and a toner sensor that detects a shortage state of toner supplied to a developing unit or a full state of toner accumulated in a cleaning unit, A sensor power supply cutoff means for cutting off the power supply to the toner sensor according to the cutoff of the drive system power supply is provided.

[Operation] In the present invention having such a configuration, when the cover forming a part of the housing is opened, the interlock switch detects it and shuts off the drive system power supply. As a result, the power supply to the photoconductor, charging unit, developing unit, transfer unit, charge eliminating unit, and fixing unit is cut off. At the same time, the toner sensor power cut-off means operates to cut off the power supply to the toner sensor. However, the piezoelectric buzzer of the toner sensor does not operate when the cover is opened.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
In this embodiment, a toner sensor circuit and a circuit including the toner sensor, which are the main parts of the present invention, will be described.

As shown in FIG. 1, the input terminal of the three-terminal regulator 51, which is a constant voltage power supply, is connected to the + 24V drive system power supply. The three-terminal regulator 51 is configured to output the same + 5V voltage as the signal system power supply to its output terminal.

Darlington-connected NPN transistors 52 and 53 are connected to the output terminal of the three-terminal regulator 51 on the emitter side through a series circuit of resistors 54 and 55.

A toner sensor 56 is composed of a piezoelectric buzzer and a piezoelectric element that generates a voltage in response to the vibration of the piezoelectric buzzer. The toner sensor 56 is connected to the output terminal of the three-terminal regulator 51 via the resistor 55. The output terminal of the toner sensor 56 is connected to the base of the transistor 52. A resistor 57 is connected between the base and collector of the transistor 52.

A diode 59 is connected to the series circuit of the resistors 54 and 55 via a coupling capacitor 58 in parallel with the polarity shown in the figure.
A resistor 60 is connected in parallel with this diode 59.

An integrating circuit including a resistor 61 and a capacitor 62 is connected in parallel to the resistor 60. The connection point between the resistor 61 and the capacitor 62 is connected to the non-inverting input terminal (+) of the comparator 63.

An NPN transistor 67 is connected to the + 5V signal system power supply through a series voltage dividing circuit of resistors 64 and 65 and a resistor 66, respectively. The connection point of the resistors 64 and 65 is connected to the inverting input terminal (-) of the comparator 63.

The output terminal of the comparator 63 is connected to the base of the transistor 67 via a resistor 68. The collector output of the transistor 67 is supplied to the I / O port 24 described above.

In this embodiment having such a configuration, + 5V is normally supplied from the three-terminal regulator 51 to the toner sensor 56.

In this state, for example, in the case where the toner sensor 56 is a toner empty sensor that detects the toner shortage in the replenishment toner box, when the toner shortage is detected, the piezoelectric buzzer operates and the piezoelectric element receives it and outputs a voltage signal. This voltage signal is amplified by the transistors 52 and 53 and is then supplied to the integrating circuit including the resistor 61 and the capacitor 62 via the coupling capacitor 58.

Then, the DC level generated across the capacitor 62 rises, and the output level of the comparator 63 is inverted from low level to high level. As a result, the transistor 67 is turned on, the collector output of the transistor 67 becomes low level, and the signal is supplied to the I / O port. As a result, the CPU 21 becomes aware of the toner shortage.

When the toner sensor 56 is the toner full sensor that detects the fullness of the discharged toner box of the cleaning unit 7, the toner sensor 56 detects the fullness of toner and the toner sensor 56 outputs a voltage signal.

When the cover is opened to replenish the replenishment toner box with toner, the interlock switch 16 is turned off and the drive system power source of the DC power source 15 is shut off. Therefore, the power supply to the photoconductor 3, the charging unit 4, the exposing unit 2, the developing unit 5, the transfer unit 6, the charge eliminating unit 8, the fixing unit 11 and the like is cut off to ensure safety.

At this time, the power supplied to the three-terminal regulator 51 is also cut off, so that the output voltage from the regulator 51 becomes zero and the power supply to the toner sensor 56 is stopped. Then, the vibration of the piezoelectric buzzer is stopped, and the oscillating sound disappears. Therefore, no unpleasant noise is heard when the cover is opened.

In this embodiment, the constant voltage power supply is composed of a three-terminal regulator, but it is not limited to this.

Next, another embodiment of the present invention will be described with reference to the drawings.
The same parts as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in Fig. 2, this is a PNP for the + 5V signal system power supply.
Form transistor 71 through transistors 52, 53, resistor 54,
A circuit composed of 55, a toner sensor 56, and a resistor 57 is connected. Resistance between the base and emitter of the transistor 71
72 are connected.

An NPN transistor 74 is connected to the signal system power supply via a resistor 73. The collector of the transistor 74 is connected to the base of the transistor 71 via the resistor 75.

A series voltage circuit of resistors 76 and 77 is connected to the drive system power source, and the connection point of the resistors 76 and 77 is connected to the base of the transistor 74.

In the present embodiment having such a configuration, when the interlock switch 16 is turned off and the drive system power supply is cut off by opening the cover, the base current is not supplied to the transistor 74 and the transistor 74 is turned off. As a result, the base current of the transistor 71 stops flowing and the transistor 71 also turns off. Thus the toner sensor 56
The supply of signal system power to the device is cut off, and the operation of the piezoelectric buzzer is stopped.

Therefore, also in this embodiment, the same effect as that of the above embodiment can be obtained.

[Effects of the Invention] As described in detail above, according to the present invention, when the cover is opened, only the drive system power supply is shut off, and the power supply to the toner sensor can be shut off by shutting off the drive system power supply. It is possible to provide a dry electrophotographic apparatus capable of preventing the generation of unpleasant sound from the piezoelectric buzzer at the time.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an essential part showing an embodiment of the present invention, FIG. 2 is a circuit diagram of an essential part showing another embodiment of the present invention, and FIG. 3 is a view showing a configuration of a dry electrophotographic apparatus. FIG. 4 is a circuit block diagram of the dry electrophotographic apparatus, and FIG. 5 is a main part circuit diagram showing a conventional example. 28 …… toner empty sensor, 29 …… toner full sensor, 30 …… toner sensor circuit, 51 …… 3-terminal regulator, 56 …… toner sensor, 71, 74 …… transistor.

Claims (3)

[Claims] 1. A power supply for a signal system and a power supply for a drive system as power supplies.
A photoconductor, a charging unit, an exposing unit, a developing unit, a transferring unit, and a charge removing unit which are provided with a system and are connected to the drive system power source and housed in a casing based on a control signal from a control unit connected to the signal system power source. Unit and the fixing unit are respectively controlled to charge the photoconductor with the charging unit, and subsequently, the exposure unit exposes image information to form an electrostatic latent image on the photoconductor. In the developing unit, toner is attached to the electrostatic latent image of the photoconductor to form a toner image, then in the transfer unit the toner image is transferred to the transfer target material, and then in the cleaning unit. After the toner remaining on the photoconductor is removed, the surface of the photoconductor is neutralized by the static elimination unit, and the toner image transferred to the transfer medium is fixed by the fixing unit, and then the transfer medium is discharged. In addition, the cover that forms a part of the housing is opened. -In a dry type electrophotographic device that detects only a drive system power supply by detecting with a lock switch, it is composed of a piezoelectric buzzer and a piezoelectric element that generates voltage in response to the vibration of the piezoelectric buzzer, and the toner supplied to the developing unit is insufficient. State or a toner sensor for detecting a full state of toner accumulated in the cleaning section, and a sensor power supply cutoff means for cutting off the power supply to the toner sensor according to the cutoff of the drive system power supply. Photographic equipment. 2. The dry electrophotographic apparatus according to claim 1, wherein the sensor power cut-off means is constituted by a constant voltage power supply whose input side is connected to a drive system power supply and whose output side is connected to a toner sensor. 3. The sensor power supply cutoff means comprises a switch circuit for cutting off the circuit in response to the cutoff of the drive system power supply, and the toner sensor is connected to the signal system power supply through the switch circuit. The dry electrophotographic apparatus according to (1).