JP2550911B2 - Toner supply control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner supply control apparatus suitable for automatically adjusting toner density in an electrophotographic apparatus adopting a developing system using a two-component developer in which toner and carrier are mixed.

[0002]

2. Description of the Related Art A conventional toner supply control device is indispensable for a stand-alone type electrophotographic apparatus, but since an operator is present near the electrophotographic apparatus, the toner exhaustion is only a warning. It is not output, and it is left to the operator's judgment to finally determine the toner exhaustion (for example, it is judged as the limit based on the printing state of the output paper from the apparatus). Note that, as a device related to this type of toner supply control device, there are those described in JP-B-55-39404 and JP-B-56-22209.

[0003]

However, in an electrophotographic apparatus, as a computer terminal such as a printer,
That is, the number of devices used as remotely operated devices is increasing. In this case, since the operator is not present near the electrophotographic device, even if the remote control device side is notified of the toner depletion warning, the remote control system is still in an operable state and the output paper The operator erroneously recognizes that the output is normal. That is, since the remote operator cannot judge it by his / her eyes even though the print density is reduced due to the toner being depleted, there is a possibility that the remote operator may perform the continuous operation in the toner depleted state.

Further, in an electrophotographic apparatus adopting a developing system with a two-component developer, if the toner concentration in the developer is extremely lowered, a carrier pulling phenomenon occurs and the apparatus is fatally damaged. . Such a phenomenon is
Even if a large amount of print instructions are issued by the operator and a toner exhaustion warning is issued during the execution of printing, the printing may continue.

An object of the present invention is to provide an electrophotographic apparatus,
An object of the present invention is to provide a toner supply control device that can reduce the harmful effects of running out of toner.

[0006]

SUMMARY OF THE INVENTION Phenomenon means of a developing system using a two-component developer in which toner and carrier are mixed, a density sensor for detecting the toner density in the developer in the developing means, and a density sensor from the density sensor. In the electrophotographic apparatus including a toner supply unit that supplies toner into the developing unit when the density determination information is thin information, and a door switch that obtains opening / closing information of a door for device maintenance, the density determination is performed from the density sensor. When the information is below the normal level, the toner supply drive means for driving the toner supply means for supplying the toner from the toner hopper and the number of times the toner supply means is driven after the toner density falls below the normal level. Counting means for counting, and toner depletion abnormality when the toner density does not become normal even if the counting means exceeds the first set value. Determination means for making a determination, notification means for giving a notification of toner exhaustion based on a signal from the determination means, means for stopping the electrophotographic process based on a signal from the determination means, and then a door switch from the door switch. When the opening / closing information changes, the counting means starts counting, the toner replenishing driving means is repeatedly driven at a predetermined time for a predetermined interval, and the density is reached before the counting means reaches the second set value. When the sensor outputs a value of a regular level, the electrophotographic process is started, and when the density determination information is equal to or less than the regular value even if the counting unit is equal to or more than the second set value, the notification unit is again provided. In addition, the control means for notifying the toner shortage is provided.

[0007]

When the electrophotographic process is activated, the toner depletion is determined from the change in the toner concentration determination information and the first toner replenishment number, and after the door open / close information is input when the toner is out, the second toner replenishment number is used. Even when the toner density does not recover, it is determined that the toner has run out, power consumption is minimized, and the user does not have to reset the electrophotographic recording apparatus to obtain a clear image.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2 and FIG. 3, the photosensitive drum 1 on which a charge latent image is formed in the electrophotographic process and rotates in the direction of arrow (a) is developed by the developing device 2. The developing device 2 adsorbs a two-component developer, which is a mixture of a carrier and a toner contained in the container 3, onto the outer circumference of the developing roll 4 to form a magnetic brush, and causes the developing roll 4 to rotate by the developing device motor 5. The developing process is performed by rubbing the photosensitive drum 1 while rotating the magnetic brush. A toner concentration sensor 6 is provided in the developer in the container 3, and when the toner concentration falls below a predetermined value, the toner supply roller 8 is driven by the supply motor 7 and the toner hopper 9 is supplied.
The toner inside is supplied into the container 3.

FIG. 1 is a block diagram of a control circuit, and FIG. 4 and FIG.
Is the operation timing chart. Main controller 10
When a start signal S1 is input from the outside, the main controller 10 starts the control for executing the electrophotographic process. Sequence control is sequentially performed, and as shown in FIG. 4, at the start of the developing process, that is, at the start of operation of the developing device 2,
After the developing device motor time t ₁ from the output of the drive signal 5 in other words (this time t ₁ may thus拌been developer is a time lag until arriving at the concentration sensor 6)
In addition, the main controller 10 inputs whether the analog signal from the density sensor 6 is equal to or higher than the normal level or lower than the normal level as a density determination signal via a density determination circuit 11 that converts it into a digital signal.

Here, if the density determination signal means dark, the main controller 10 does not perform the toner supply operation. However, since the toner in the developer in the container 3 adheres to the charge latent image on the photosensitive drum 1, it is consumed every time a toner image is formed (developing process), and the toner concentration in the developer gradually decreases. When the toner concentration in the developer is lower than the normal level, the density determination signal after the time t _{1 has} elapsed is input to the main controller 10 meaning that the density is low. The main controller 10 to which the signal is applied urges the toner supply motor 7 for a predetermined set time t ₂ to rotate the toner supply roller 8 to move the toner in the toner hopper 9 into the container 3. Supply. When the toner is stored in the toner hopper 9, the toner concentration in the developer rises and returns to the normal level or higher by the above-described supply operation, and thereafter,
Even when the toner concentration in the developer decreases again, the toner concentration in the developer is always kept within a constant level range (near the normal level) by the same supply operation as described above.

When such a toner supply operation is repeated,
The toner in the toner hopper 9 gradually decreases and finally disappears. As shown in FIG. 4, in the main controller 10 to which the information of the remaining toner amount is not input, “light” is repeatedly input as the density determination signal. Therefore, the main controller 10 repeats the control for driving the toner supply motor 7 for the time t ₂ , but since the toner does not exist in the toner hopper 9, the toner is not supplied and the toner concentration in the developer decreases. Then, finally, the image density formed on the output paper is reduced to near the sea level.

In this embodiment, the toner amount consumed during one cycle of such toner supply operation is M _a ,
Toner supply operation of the _{M t> n × M a ...} ( Equation 1) and a number n (times) when the amount of toner from the concentration determination signal becomes "thin" until the critical level was M _t When repeated continuously, main controller 10 determines that toner is no longer present in toner hopper 9, generates out-of-toner abnormal signal S2, and erases device ready signal S3. The signals S2 and S3 are used, for example, to display out of toner on the display panel of the apparatus or to notify the remote control side of the state of the apparatus. Also,
The main controller 10, which has output the toner-out warning signal S2,
The subsequent start signal S1 is ignored, and the execution of the electrophotographic process is held in a stopped state until the toner-out warning signal S2 disappears.

The toner hopper 9 is manually operated by the operator who recognizes the toner shortage by the toner shortage warning signal S2.
It is assumed that the toner has been replenished. The main controller 10 uses the on / off information of the door switch 12 (which is originally a kind of safety switch provided to protect the operator) that responds to the opening and closing of the maintenance door provided in the device, It is estimated that the above-mentioned toner supply has been performed. Of course, opening and closing of the door (OFF / ON of the door switch 12) may be performed by the operator for purposes other than toner replenishment.
0 can recognize this by the determination operation described later.

FIG. 5 shows a case where the manual operation of toner supply is not performed.

The main controller 10 to which the OFF / ON information of the door switch 12 is input drives the developing device motor 5 to stir the developer and at the same time drives the toner supply motor 7 for t ₃ . The amount of toner to be supplied by this is M _s
And Main controller 10 determines the concentration determination signal when time t _{4 has} elapsed. This series of operations is called a development density adjusting operation. In the case of this example, since the toner replenishment is not performed manually, the toner density in the developer does not rise, and the density determination signal remains "thin".
The main controller 10 which has received this signal repeats the above-mentioned developer concentration adjusting operation again. Then, when the maximum warming-up time of the apparatus is T, and the number of times m (times) where T> m × t ₄ (Equation 2) is satisfied, the main controller 10 performs manual toner replenishment work. It is determined that the failure has not occurred, and the out-of-toner abnormality signal S2 is generated, and the operator is again informed of the abnormality.

On the other hand, FIG. 5 shows a case where the operator manually carries out toner replenishment.

The main controller 10 to which the OFF / ON information of the door switch 12 is inputted starts the above-mentioned developer concentration adjusting operation. In this case, the toner concentration in the developer rises every time the developer concentration adjusting operation is performed, and finally returns to the normal level.

It is also possible to determine the toner amount M _t up to the critical level of the toner concentration in the developer so that the condition of M _t <m × M _S (Equation 3) is satisfied.
Of course, if the toner concentration in the developer becomes equal to or higher than the normal level before the repeating operation reaches m times, the developer concentration adjusting operation is immediately ended, the toner out abnormality signal S2 is disappeared, and the device ready signal S3 is set. When it is generated, the operator is informed that the toner out abnormality has been canceled. After that, main controller 10 can receive start signal S1.

According to this embodiment, since the toner concentration in the developer cannot be lower than the critical level, it is possible to prevent the fatal damage of the apparatus without causing the carrier pulling phenomenon.

Further, according to the present embodiment, the main controller 10 determines from the ON / OFF information of the door switch 12 and the density determination signal whether or not the operator manually performs toner replenishment. The troublesomeness of inputting the completion of the manual work into the device is eliminated, and the operation becomes easy.

Furthermore, according to this embodiment, the toner density in the developer can be returned to the normal level during warming up, so that output paper having a stable image density can be obtained after the toner is replenished.

Furthermore, according to this embodiment, without changing the conventional hardware configuration, for example, if a microcomputer is used for the main controller 10, it can be implemented by only changing the software. There is no cost increase due to increased parts.

[0024]

According to the present invention, it is possible to prevent the toner concentration in the developer from falling below the critical level.
This has the effect of preventing the carrier pulling phenomenon, which is one of the fatal damages of the device. Further, since the density adjustment operation is automatically performed based on the opening / closing information of the door switch after the toner replenishment manual operation, there is an effect that the operation is easy and stable image quality is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a control circuit of the present invention.

FIG. 2 is a side view of the developing unit of the present invention.

FIG. 3 is a front view of a developing unit according to the present invention.

FIG. 4 is a timing chart of toner supply when the electrophotographic process is activated.

FIG. 5 is a timing chart of toner supply when the electrophotographic process is stopped.

[Explanation of symbols]

3 ... Container, 6 ... Density sensor, 7 ... Toner supply motor,
8 ... Toner supply roller, 9 ... Toner hopper, 10 ... Main controller, 12 ... Door switch.

Claims (1)

(57) [Claims] 1. A phenomenon means of a developing system using a two-component developer in which a toner and a carrier are mixed, a density sensor for detecting the toner density in the developer in the developing means, and density determination information from the density sensor. In an electrophotographic apparatus including a toner supply unit that supplies toner into the developing unit when the information is thin, and a door switch that obtains opening / closing information of a device maintenance door, the density determination information from the density sensor is normal. Toner replenishment drive means for driving the toner supply means for replenishing toner from the toner hopper when the level becomes lower than the level, and counting means for counting the number of times the toner supply means is driven after the toner concentration becomes lower than the normal level. And a judgment means for judging the toner out-of-abnormal condition when the toner density is not in the normal state even when the counting means exceeds the first set value. A step, an informing means for informing of toner exhaustion based on the signal from the judging means, a means for stopping the electrophotographic process based on the signal from the judging means, and thereafter opening / closing information from the door switch. When it changes, the counting means starts counting, the toner replenishing driving means is repeatedly driven for a predetermined time at a predetermined interval, and the density sensor is normally operated before the counting means reaches the second set value. When the value of the level is output, the electrophotographic process is started, and when the density determination information is equal to or less than the normal value even when the counting unit is equal to or more than the second set value, the notification unit again runs out of toner. A toner supply control device characterized by comprising a control means for informing.