JPH05134547A - Developing device - Google Patents

Abstract

PURPOSE:To judge whether a developer is brand new or not without adding parts for detection by comparing the output value of a toner sensor with a reference value and judging that the developer is brand new when the output value is larger by a specified value. CONSTITUTION:The toner sensor 4 detects the toner concn. of the developer and outputs a detection signal to a controller 6. A comparing means 30 compares the output value of the toner sensor 4 with the reference value. A developer discriminating means 31 judges that the developer is brand new if the output value of the toner sensor 4 is larger by the specified value than the reference value at this time. An agitating means 32 drives a main motor 10 to rotate a magnet roller and an agitating roller by an agitating means 32 in accordance with the result of the judgment, thereby agitating the developer. The electrification quantity is then increased by the friction of the developer and the output value of the toner sensor 4 is successively decreased until its output voltage stabilizes to the reference value. The state of the developer is thus discriminated by the output of the toner sensor 4 at the time of initialization of the developing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an initial control of an image forming apparatus when the developer in the developing apparatus is replaced with a new one or when the developing apparatus itself is replaced with a new one.

[0002]

2. Description of the Related Art In a developing device such as a laser printer, when the life of the developer is reached, the developer is replaced with a new one or the developing device is replaced with a new one every unit.

In the case of a new developer, since the charge amount is small, the apparent density is large, and the volume is small, the output voltage of the toner sensor using the magnetic permeability sensor is initially high. As the magnet roller, the stirring roller, etc. rotate, the charge amount of the developer increases, the apparent density decreases and the volume increases, so that the output voltage of the toner sensor decreases and the output becomes constant when saturated.

However, if the developing device does not have a mechanism for detecting whether or not the developer is new, the output voltage of the toner sensor is controlled to become the reference voltage, so that the toner is replenished when the initial output voltage is high. To be done.

Further, since the magnet roller and the like of the developing device are rotationally driven until the toner density rises and fog becomes large or the reference voltage is reached, there is a problem that the warm-up time of the device becomes long.

Therefore, the developing device is provided with a fuse for detecting whether or not the developer is new.

Thus, as shown in FIG. 10, when the main switch is turned on, the fuse determines the state of the developer.

When the developer is new, the toner replenishing motor is turned off and the magnet roller or the like is rotationally driven for one or two minutes.

When the developer is not new, the toner replenishing motor is driven according to the output voltage of the toner sensor.

[0010]

As described above, electric parts such as fuses must be added to detect a new developer, and the cost increases due to the mounting work and increase in the number of parts. I will end up.

In view of the above, it is an object of the present invention to provide a developing device capable of determining whether a developer is new or not without adding a component for detecting a new developer.

[0012]

As shown in FIGS. 1 and 2, a developing tank 1 and rollers 2 and 3 rotatably mounted in the developing tank 1 are provided. A toner sensor 4 having a characteristic that the toner concentration in the developing tank 1 is detected and its output value V1 gradually decreases with an increase in the toner concentration; and a toner replenishing means 5 for replenishing the developing tank 1 with toner. A control device 6 for controlling the driving of the rollers 2, 3 and the toner replenishing means 5 according to the output signal from the toner sensor 4 is provided, and the control device 6 outputs the output value V1 of the toner sensor 4 and the reference value V2. The comparing means 30 for comparing the developer, the developer determining means 31 for determining that the developer is new when the output value V1 of the toner sensor 4 is larger than the reference value V2 by a certain value, and the developer determining means 31. The developer is new The rollers 2 and 3 when it is determined that
And a normal driving means 33 for driving the rollers 2, 3 and the toner replenishing means 5 until the output value V1 of the toner sensor 4 reaches the reference value V2 when it is determined that the developer is not new. It has been marked with and.

As shown in FIG. 8, the means for solving the problem according to claim 3 is a comparison means 30 for comparing the output value V1 of the toner sensor 4 with the reference value V2 when the power is turned on, and the output value V1 of the toner sensor 4 is the reference value. When the developer is newer than V2 by a certain value, the developer determining unit 31 determines that the developer is new, and when the developer determining unit 31 determines that the developer is new, warm-up is performed to form an image. And a normal driving means for driving the rollers 2, 3 and the toner replenishing means 5 until the output value V1 of the toner sensor 4 reaches the reference value V2 when it is determined that the developer is not new. 33 and 33.

[0014]

In the means for solving the problems according to claims 1 and 2, the toner sensor 4 detects the toner concentration of the developer,
When the detection signal is output to the control device 6, the comparison unit 30 compares the output value V1 of the toner sensor 4 with the reference value V2. At this time, when the developer is new, the output value V1 is the virgin value V3 (> V2).

Then, the developer determining means 31 determines that the developer is new, and based on the result of the determination, the stirring means 32 causes the magnet roller 2 and the stirring roller 3 to be used.
Is rotated. Then, the rollers 2 and 3 rotate,
The developer is agitated, the charge of the developer increases due to friction of the developer, the output value V1 of the toner sensor 4 decreases, and the output voltage stabilizes to the reference value V2.

As described above, the state of the developer can be determined by the output of the toner sensor 4 when the developing device is initialized.

In the third aspect, when the developer is new, the magnet roller 2 and the stirring roller 3 are unconditionally rotated for the time required for warm-up regardless of the output of the toner sensor 4. Then, the printer is put in a printable state and waits.

[0018]

1 is a functional block diagram of a controller of a developing device showing an embodiment of the present invention, FIG. 2 is a sectional view of the developing device, FIG. 3 is a flow chart when detecting the initial of the developer, and FIG.
Is an output waveform diagram of the toner sensor, FIG. 5 is a circuit diagram of the toner sensor, FIG. 6 is a configuration diagram of a laser printer including the developing device of the present invention, and FIG. 7 is an image forming process diagram of the laser printer.

As shown in FIG. 2, the developing device of this embodiment comprises a developing tank 1 and rollers 2 rotatably mounted in the developing tank 1.
3, a toner sensor 4 having a characteristic that the toner concentration in the developing tank 1 is detected and its output value V1 gradually decreases with an increase in the toner concentration, and a toner replenishing means 5 for replenishing the developing tank 1 with toner. And a control device 6 for controlling the driving of the rollers 2, 3 and the toner replenishing means 5 according to the output signal from the toner sensor 4.

The roller is composed of a magnet roller 2 arranged near the opening 7 of the developing tank 1 so as to face the photoconductor 8 and a stirring roller 3 arranged below the toner supply port 9.
The rollers 2 and 3 are rotationally driven by the main motor 10.

The toner sensor 4 is a magnetic permeability sensor which is attached to the tank wall of the developing tank 1 and which converts the magnetic permeability of the developer into a voltage and outputs the voltage. As shown in FIG. It is provided with coils L1, L2, L3 and an exclusive OR circuit IC.

The toner replenishing means 5 includes a toner hopper 11 mounted in the developing tank 1, a toner agitator 12 rotatably mounted in the toner hopper 11, and a toner replenishing roller 13 arranged in the toner replenishing port 9. , A toner motor 14 for driving the toner replenishing roller 13 and the toner agitator 12. In FIG. 2, reference numeral 15 is a polyethylene terephthalate (PET) shutter member, 16
Is a lid of the toner hopper 11.

The developing device as described above is detachably mounted as a cartridge on the laser printer main body 20 as shown in FIG. In the figure, 21 is a photoconductor,
A process unit in which a charging device and a cleaning device are integrated, 22 is an optical unit such as a semiconductor laser, and 23.
Is a paper feed cassette, 24 is a paper feed roller, 25 is a PS roller, 26 is a fixing roller, and 27 is a paper discharge roller.

Since the image forming process and the sheet conveying process of the laser printer are known as shown in FIG. 7, detailed description thereof will be omitted.

When the developing device is attached to the printer body 20 and the main switch is turned on to turn on the power,
In order to perform an initial detection as to whether or not the developer is new, the control device 6 of the developing device, as shown in FIG. 1, has a comparison means 30 for comparing the output voltage V1 of the toner sensor 4 with the reference voltage V2. , The developer determining unit 31 that determines that the developer is new when the output voltage V1 of the toner sensor 4 is higher than the reference voltage V2 by a certain voltage, and the developer determining unit 31 determines that the developer is new. When the developer is not new, the agitating means 32 for driving the magnet roller 2 and the agitating roller 3 is used, and when it is determined that the developer is not new, the toner sensor 4 is provided with the agitating means 2, 3.
And an ordinary driving means 33 that drives the output voltage V1 of the above-mentioned output voltage V1 to the reference voltage V2.

When the developer is new, the toner sensor 4
As shown in FIG. 4, the output voltage V1 of the first output is high, and the output gradually decreases as the developer is stirred.
In a minute, a steady state is reached and a constant voltage V2 is reached.

Therefore, with V2 as a reference voltage, a voltage higher by ΔV than this is taken as a virgin voltage V3.

It should be noted that ΔV is set based on the voltage generated only when the developer is new, without being generated in a normal process.

That is, during the normal process, for example, when black solid is printed, the toner consumption amount is 0.5 g or less, and when the toner drop amount is 5 g / min, the consumed toner is recovered in about 6 seconds. To do. As described above, since the toner is replenished during printing, the output voltage of the toner sensor does not rise at once.

If the sensor sensitivity is 0.3V / WT% and ΔV is set to 0.3V, the toner density changes by 1%. Here, the toner density is 4
When the amount of developer is 200 g in%, 8 g in this developer
When the black solid is printed, 0.5g of toner is consumed and the toner density is 3.75%.
Becomes Therefore, a change in toner concentration of 1% does not occur in the normal process.

The developer determining means 31 determines that the developer is new when the output voltage of the toner sensor 4 is V1 ≧ V3 (= V2 + ΔV), and determines that the developer is not new when V1 <V3. .. Further, it also has a function of comparing V1 with V2 and discriminating whether the toner density is high or low based on the magnitude thereof.

The agitating means 32 has a function of driving the main motor 10 while the toner motor 14 is off, and the normal driving means 33 has a toner density when the output voltage of the toner sensor 4 is V1 ≧ V2. Since it is low, the toner motor 14 is driven for a maximum of 1 minute to replenish the toner, and V1
When <V2, the toner density is high, so the toner motor 14
Has the ability to remain off.

In the above structure, when the main switch is turned on, the toner sensor 4 detects the toner concentration of the developer and outputs a detection signal to the control device 6.

The output voltage V1 of the toner sensor 4 is compared with the reference voltage V2 by the comparison means 30 of the control device 6.
At this time, when a new developing device is attached to the printer body and the developer is new, the output voltage V1 is the virgin voltage V3.

Then, the developer determining means 31 determines that the developer is new, and based on the result of the determination, the stirring means 32 causes the magnet roller 2 and the stirring roller 3 to be used.
A drive signal is output to the main motor 10 to rotate the.

While the toner motor 14 is stopped, the rollers 2 and 3 are rotated for 1 to 2 minutes to stir the developer. As a result, the amount of charge increases due to the friction of the developer, the output voltage V1 of the toner sensor 4 decreases, and the output voltage stabilizes and becomes the reference voltage V2.

In the case of a developing device that has been used, the output voltage V1 of the toner sensor 4 is smaller than V3, the comparison means 30 compares the output voltage V1 with the reference voltage V2, and the developer determining means 31 develops the developer. Is judged not to be new.

When the output voltage V1 is higher than the reference voltage V2 by the normal driving means 33, the toner density is low, so that the toner motor 14 and the main motor 10 are driven to replenish the toner. The toner supply roller 13 rotates, the toner is supplied from the toner hopper 11 to the developing tank 1, and the developer and the toner are stirred by the rotation of the magnet roller 2 and the stirring roller 3.

When the output voltage V1 of the toner sensor 4 becomes equal to the reference voltage V2, the toner motor 14 is turned off to stop the toner replenishment, and the image forming process is in a standby state.

If the toner motor 14 is continuously turned on for 1 minute or more, it is determined that the developing device is abnormal,
Error processing is executed by the control device.

When the output voltage V1 of the toner sensor 4 is lower than the reference voltage V2, the toner density is sufficiently high, so that it is not necessary to replenish the toner, the toner motor 14 remains off, and the developing device is in the standby state. Be scented.

As described above, when the developing device is initialized, the state of the developer can be discriminated by the output of the toner sensor 4. Therefore, it is not necessary to separately provide a fuse, unlike the conventional case, and existing components can be used. However, the cost is not high.

However, in the above embodiment, when the main switch is turned on and the developer is new, the magnet roller 2 and the agitating roller 3 are driven, and the output voltage of the toner sensor 4 decreases and becomes stable. Since it takes a long time, the warm-up time becomes long.

Therefore, as another embodiment, when the developer is new, in order to print in the shortest time,
As shown in FIG. 8, the control device 40 of the developing device controls the comparison means 30 for comparing the output voltage V1 of the toner sensor 4 with the reference voltage V2 when the power is turned on, and the output voltage V of the toner sensor 4.
When 1 is larger than the reference voltage V2 by a certain voltage, the developer determining means 31 determines that the developer is new, and when the developer determining means 31 determines that the developer is new, warm-up is performed. Then, the preparation means 41 for standing by in a state where an image can be formed and the rollers 2, 3 and the toner replenishing means 5 are driven until the output voltage V1 of the toner sensor 4 becomes the reference voltage V2 when it is determined that the developer is not new. It is provided with a normal drive means 33 that operates.

The preparation means 41 causes the printer to warm up in the shortest time regardless of the output of the toner sensor 4 so that one sheet can be printed unconditionally without fail, and the second and subsequent sheets can be printed by the normal toner sensor 4. It has a function of controlling the developing device so that the output voltage V1 becomes the reference voltage V2.

Here, the shortest time required for warm-up is to rotate the polygon mirror until it is locked, turn on the laser beam and turn on the main motor to perform high-pressure check and toner concentration check, turn off the main motor, It takes 4 to 6 seconds until the laser light is turned off. During the period from when this main motor is on to when it is off, the magnet roller 2
And the stirring roller 3 is driven.

The other structure is the same as that of the above embodiment.

Thus, by controlling the printer, when the developer is new as shown in FIG. 9, the magnet roller 2 and the stirring roller 3 are unconditionally irrespective of the output of the toner sensor 4. It is rotated for the time required to warm up. Then, the printer is put in a printable state and waits.

Therefore, in the case of a new developer, since the output voltage of the toner sensor 4 is high, the warm-up time until the toner density becomes the reference value becomes long, and the problem that the first printing is delayed is solved. can do.

For the second and subsequent sheets, the control based on the reference value of the toner density eliminates the influence of the print density of the first sheet, stabilizes the output of the toner sensor 4, and causes the variations in the toner density. Can be made smaller.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

The toner sensor 4 of this embodiment uses a magnetic permeability sensor, but it can also be applied to a sensor that has an opposite characteristic, that is, an output that is directly proportional to the toner concentration. In this case, the virgin output is the reference. The value is lower than the value by a certain value.

[0053]

As is apparent from the above description, according to claims 1 and 2 of the present invention, the toner having the characteristic that the toner concentration in the developing tank is detected and the output value thereof is gradually decreased with the increase of the toner concentration. By comparing the output value of the sensor and the reference value, it is possible to determine that the developer is new when the output value of the toner sensor is larger than the reference value by a certain value. Therefore, a conventional fuse is separately provided. There is no need, and existing parts can be used, and the cost does not increase.

By driving only the roller when it is judged that the developer is new, the toner is not replenished when the developing device is initialized, so that the toner density does not rise excessively and the toner density is quickly increased. It can be set to the standard concentration.

According to the third aspect, the output value of the toner sensor is compared with the reference value when the power is turned on, and when the output value of the toner sensor is larger than the reference value by a certain value, it is determined that the developer is new. By performing warm-up and waiting in an image-formable state, the roller is unconditionally rotated for the time required for warm-up regardless of the output of the toner sensor, and the print-ready state is awaited. With a new developer, the time required for warm-up until the toner concentration reaches the reference value becomes long, and the problem that the first print is delayed can be solved.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a controller of a developing device showing an embodiment of the present invention.

FIG. 2 is a sectional view of a developing device.

FIG. 3 is a flow chart when the initial of the developer is detected.

FIG. 4 is an output waveform diagram of a toner sensor.

FIG. 5 is a circuit diagram of a toner sensor.

FIG. 6 is a configuration diagram of a laser printer including the developing device of the present invention.

FIG. 7 is an image forming process diagram of a laser printer.

FIG. 8 is a functional block diagram of a control device showing another embodiment.

FIG. 9 is a flow chart when the initial of the developer is similarly detected.

FIG. 10 is a flow chart at the time of detecting the initial of a conventional developer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing tank 2 Magnet roller 3 Stirring roller 4 Toner sensor 5 Toner replenishing means 6 Control device 30 Comparing means 31 Developer judging means 32 Stirring means 33 Driving means 40 Control device 41 Preparing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Ando 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Takashi Sugito 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Yap Co., Ltd.

Claims (3)

[Claims] 1. A developing tank, a roller rotatably mounted in the developing tank, and a toner having a characteristic of detecting a toner concentration in the developing tank and gradually decreasing its output value with an increase in the toner concentration. In a developing device provided with a sensor, a toner replenishing means for replenishing the developing tank with toner, and a control device for controlling the driving of the roller and the toner replenishing means by an output signal from the toner sensor, the control device is Comparing the output value of the toner sensor with a reference value, and a developer determining means for determining that the developer is new when the output value of the toner sensor is larger than the reference value by a certain value. A developing device characterized by the above. 2. The control device according to claim 1, wherein when the developer determining means determines that the developer is new, the stirring means drives only the roller, and when the developer is determined not to be new, the agitating means is used. A developing device, comprising: a roller and a toner replenishing means, and a normal driving means for driving the toner sensor until the output value of the toner sensor reaches a reference value. 3. A developing tank, a roller rotatably mounted in the developing tank, and a toner having a characteristic that the toner concentration in the developing tank is detected and its output value is gradually decreased with an increase in the toner concentration. In a developing device provided with a sensor, a toner replenishing means for replenishing the developing tank with toner, and a control device for controlling the driving of the roller and the toner replenishing means by an output signal from the toner sensor, the control device is A comparing means for comparing the output value of the toner sensor with a reference value when the power is turned on; and a developer determining means for determining that the developer is new when the output value of the toner sensor is larger than the reference value by a constant value. When the developer determination unit determines that the developer is new, a warm-up process is performed to prepare the image forming apparatus for standby, and the developer is determined not to be new. The developing device is provided with normal driving means for driving the roller and the toner replenishing means until the output value of the toner sensor reaches a reference value.