JPH0723978B2 - Toner supply control device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrophotographic apparatus adopting a developing system using a two-component developer in which a toner and a carrier are mixed, and a toner suitable for automatically adjusting the toner density. The present invention relates to a supply control device.

[Background of the Invention]

The conventional toner supply control device is indispensable for a stand-alone type electrophotographic device, but since the operator is near the electrophotographic device, the toner exhaustion is output only as an abnormality notification. Finally, the determination of the toner exhaustion (for example, the limit is determined by the printing state of the output paper from the apparatus) is left to the operator's determination.

However, an increasing number of electrophotographic devices such as printers are remotely operated as computer terminals. This device usually does not have an operator resident near it, and since the device is in a state where printing can be performed even when the toner out-of-range abnormality is notified, the print density decreases due to toner depletion. Even if it is, the operation may be continued by erroneously recognizing that normal printing is being performed.

If such a state continues in an electrophotographic apparatus using a two-component developer, the toner concentration in the developer will be extremely reduced, causing carrier pulling development, which will cause fatal damage to the apparatus.

Therefore, the improved electrophotographic apparatus detects the toner concentration in the developer and controls the toner supply, and when the toner concentration does not recover even if the toner supply is continued, the toner in the toner hopper is exhausted. In addition, the toner out-of-abnormality is notified and the electrophotographic process is stopped. Then, when the door for maintenance of the apparatus is opened and closed, it is considered that new toner has been replenished in the toner hopper, and the toner out-of-range abnormality notification and the stop of the electrophotographic process are automatically released.

This type of control device is disclosed in Japanese Utility Model Publication No. 56-161651 and Japanese Unexamined Patent Publication No.
No. 54-96047.

However, in the conventional control device of this kind, when the maintenance door of the device is opened and closed and the electrophotographic process is notified when the maintenance door of the device is opened and closed in the toner release abnormality notification and the automatic release control of the electrophotographic process stop when the toner is out. Since the stop of is stopped, the printable state is restored without toner supply. Since this recovery is a pseudo recovery state, the toner runs out abnormally soon after printing is started, but if such a pseudo recovery state is repeatedly generated and printing is continued, the toner concentration gradually decreases and Damage caused by
There is a problem that the correct automatic release cannot be realized.

[Object of the Invention]

An object of the present invention is to provide carrier pulling that occurs when printing is performed in a pseudo recovery state in the above-mentioned toner outage abnormality notification and electrophotographic process stop automatic release control in an electrophotographic apparatus. The present invention is intended to prevent the damage due to the above-mentioned phenomenon and to make it possible to re-notify the abnormal recovery of the toner out (non-recovery state) in a timely manner so that the correct automatic release can be realized without a feeling of discomfort.

[Outline of Invention]

The present invention relates to a developing 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 density determination information from the density / density sensor. When the density information is thin information, the toner supply means for supplying the toner into the developing means and the density sensor continuously inputs the density determination information a plurality of predetermined times. Toner out detection means for notifying the toner out abnormality while stopping the electrophotographic process of the apparatus, a door switch for obtaining opening / closing information of the door for maintenance of the apparatus, and the door switch after the electrophotographic process stop and toner out abnormality notification In the electrophotographic apparatus provided with an automatic cancellation control device for canceling the stop and abnormality notification when the opening / closing information from the When the opening / closing information from the door switch changes after the electrophotographic process stop and abnormality notification to the removal control device, the density determination information from the density sensor is dark information in the state where the stopped state of the electrophotographic process is maintained. When the toner supply unit is driven so as to supply toner until the temperature reaches a certain level, and the density determination information is restored to dark information by toner supply with the maximum warm-up time of the electrophotographic apparatus as an upper limit from the change in the door switch opening / closing information. Is equipped with control means for canceling the stopped state of the electrophotographic process, and stopping the toner supply means and re-notifying the toner out abnormality if it does not recover, and replenishing toner even if the device maintenance door is opened and closed. Hold the electrophotographic process until the toner density is restored and pull the carrier. The electrophotographic apparatus is operated within the maximum waiting time to prevent the apparatus from being damaged and to release the stop state to enable the printing operation or to stop the toner supply and re-notify the toner out abnormality. This is to enable correct automatic release without giving the person a feeling of strangeness.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In FIGS. 2 and 3, the photosensitive drum 1 on which a latent charge image is formed by the electrophotographic process and rotates in the arrow (a) direction 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 motor 5 to rotate the developing roll 4. While rotating the magnetic brush, the photosensitive drum 1
Is rubbed against to perform the development process. Container 3
A toner concentration sensor 6 is provided in the developer inside, and when the toner concentration falls below a predetermined value, the toner replenishing roller 8 is driven by the supply motor 7 and the toner in the toner hopper 9 is supplied into the container 3. It

FIG. 1 is a block diagram of the control circuit, and FIGS. 4 and 5 are operation timing charts thereof. When a start signal S1 is input to the main controller 10 from the outside, the main controller 10 starts the control executed by the electrophotographic process. The sequence control is sequentially performed, and as shown in FIG. 4, at the start of the developing process, that is, at the start of the operation of the developing device 2, in other words, after a time t ₁ from the output of the drive signal of the developing device motor 5 (this time At t ₁ , the well stirred developer is the density sensor 6
It is a time lag until it arrives at the main controller 10
Is inputted as a density determination signal through a density determination circuit 11 which changes the analog signal from the density sensor 6 into a digital signal which is equal to or higher than a normal level.

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, the toner is consumed in each toner image formation (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 a lapse of time t ₁ is input to the main controller 10 meaning that the density is low. The main controller 10 to which the signal is given is for a predetermined set time for the toner supply motor 7.
During the time t ₂ , the toner supply roller 8 is rotated to supply the toner in the toner hopper 9 into the container 3. When the toner is stored in the toner hopper 9, the toner concentration in the developer rises to the normal level or higher due to the above-mentioned supply operation, and then the toner concentration in the developer again decreases. By the same supply operation as described above, the toner concentration in the developer is always kept within a constant level range (near the normal level).

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

In the present embodiment, the amount of toner consumed during one cycle of such a toner supply operation is Ma, and the amount of toner from when the density determination signal becomes “light” to when it reaches a critical level.
When Mt> n × Ma (1), the number of times n (times) of toner supply operation is continuously repeated, the main controller 10 detects that toner is present in the toner hopper 9. It is determined that the toner has run out, the out-of-toner abnormality signal S2 is generated, and the ready signal S3 of the apparatus disappears.
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. Further, the main controller 10 that has output the toner-out abnormality signal S2 ignores the subsequent start signal S1 and holds the execution of the electrophotographic process in a stopped state until the toner-out abnormality signal S2 disappears.

It is assumed that the operator who has recognized the toner shortage by the toner shortage abnormality signal S2 manually replenishes the toner hopper 9 with toner. The main controller 10 is a door switch 12 (a kind of safety switch originally provided to protect an operator) that responds to the opening and closing of a maintenance door provided in advance in the device.
It is estimated that the toner replenishment described above has been performed based on the OFF / ON information of. Of course, the operator may open and close the door (turn on / off the door switch 12) for purposes other than toner replenishment, but the main controller 10 can recognize this by a determination operation described below.

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

The main control device 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 time t ₃ . The toner amount to be supplied by this is M _S. Main controller 10 determines the concentration determination signal when time t _{4 has} elapsed. This series of operations is called a developer concentration adjusting operation. In 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. When the maximum warming-up time of the apparatus is T, and T> m × t ₄ (2), the number of times m (times) When the above operation is repeated, the main control unit 10 causes the toner replenishment manual operation to be performed. When it is determined that the abnormality has not occurred, an out-of-toner abnormality signal S2 is generated, and the abnormality is notified again. The timing for determining that the toner has not been replenished is that the electrophotographic process is kept in the stopped state during this period and the operator enters the "wait" state.
If the number of times of the developer concentration adjusting operation up to the determination becomes excessive, the waiting time becomes long and the operator feels uncomfortable.
In this respect, the maximum warm-up time is a time length that is normally experienced as a waiting time of the apparatus, and therefore, if the determination timing is set with the maximum warm-up time as an upper limit, the operator will not feel uncomfortable.

On the other hand, FIG. 5 shows the case where the operator manually performs toner supply.

The main controller 10 to which the OFF / ON information of the door switch 12 is input starts the above-described 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 Mt up to the critical level of the toner concentration in the developer so that the condition of Mt <m × M _S (3) holds. 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 terminated, the toner-out abnormality signal S2 disappears, 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 accept start signal S1.

According to the present embodiment, the toner concentration in the developer cannot be lower than the critical level, so that the fatal damage to the apparatus can be prevented without causing the carrier pulling phenomenon.

Further, according to the present embodiment, since the main control device 10 determines whether or not the toner replenishment manual operation is performed by the operator from the ON / OFF information of the door switch 12 and the density determination signal, the operator can perform the toner replenishment manual operation. The troublesomeness of inputting completion to 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 the warming up, so that the output paper having a stable image density can be obtained after the toner is replenished.

Furthermore, according to the present 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, and the number of parts can be increased. There is no cost up due to such reasons.

〔The invention's effect〕

According to the present invention, after the electrophotographic process is stopped and the toner exhaustion abnormality is notified, in the automatic release in response to the opening and closing of the door for the maintenance of the apparatus, the toner of the electrophotographic process is restored until the toner concentration is restored and the toner density is recovered. Since the stop state is not released, it is possible to prevent the device from being damaged by pulling the carrier and to determine whether to release the stop state to enable the printing operation or to stop the toner supply and re-notify the toner out abnormality. Since it is performed within the maximum warm-up time of the photographic device, the waiting time becomes long, and the correct automatic cancellation can be realized without giving the operator a feeling of strangeness.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a block diagram of a control circuit, FIG. 2 is a side view of a developing section, FIG. 3 is a front view of the same, FIG. 4 and FIG. It is a chart. 3 ... Container, 6 ... Density sensor, 7 ... Toner supply motor, 8 ... Toner supply roller, 9 ... Toner hopper, 10 ... Main controller, 12 ... Door switch.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-54-96047 (JP, A) JP-A-58-198068 (JP, A) JP-A-56-75662 (JP, A) JP-A-55- 164848 (JP, A) JP 55-151667 (JP, A) Actually developed 56-161651 (JP, U)

Claims (1)

[Claims] 1. A developing 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 density of toner in the developer in the developing means, and a density determination from the density sensor. When the information is thin information, if the toner supply means for supplying the toner into the developing means and the density determination information from the density sensor are inputted for a predetermined number of times in succession, Toner out detection means for notifying the toner out abnormality while stopping the electrophotographic process of the electrophotographic apparatus, a door switch for obtaining the opening / closing information of the door for device maintenance, and the electrophotographic process stop and toner out abnormality notification after the above In an electrophotographic apparatus having an automatic release control device for releasing the stop and abnormality notification when the opening / closing information from the door switch changes, If the opening / closing information from the door switch changes after the electrophotographic process stop and abnormality notification, the removal control device maintains the stopped state of the electrophotographic process and the density determination information from the density sensor is dark information. The toner supply means is driven so as to supply the toner until it reaches the upper limit, and the maximum warm-up time of the electrophotographic apparatus is set as the upper limit based on the change in the opening / closing information from the door switch, and the driving of the toner supply means is repeated a plurality of times during that time. If the density determination information is restored to the dark information during that time, the stopped state of the electrophotographic process is released, and if not restored, the toner supply unit is stopped and the toner out abnormality is re-notified. A toner supply control device comprising control means.