JPH0473672A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the fault of a toner replenishing motor by stopping the operation of the toner replenishing motor when a toner presence detecting sensor detects that toner is required for being replenished to a toner case not withstanding that the value of a timer exceeds a prescribed one. CONSTITUTION:When foreign matter is mixed in carried toner so that the rotations of first and second toner carrying screws 15 and 25 are stopped, the toner is not replenished to the toner case 12. Therefore, even if the count value (t) of the timer 42 exceeds the prescribed value (t0), the sensor 14 continuously detects that the toner is required for being replenished to the toner case 12. Thus, when t > t0 is obtained, an abnormality generating signal is outputted from a comparing/deciding means 44 to an abnormality processing means 45, and therefrom to a copy sequence control means 39 to execute an abnormality processing action. In other words, a clutch 29 and the toner replenishing motor 23 are turned off by the output from the copy sequence control means 39, and simultaneously, the timer is turned off. Thus, the fault of the motor can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device that visualizes an electrostatic latent image formed on a latent image carrier using toner.

[Conventional technology]

2. Description of the Related Art It has been well known to use a developing device of the above type in an image forming apparatus such as an electronic copying machine, a printer, or a facsimile machine. In addition, this type of developing device is equipped with a replenishment toner container in addition to a toner case containing toner used for visualizing a latent image, and a toner presence detection sensor installed in the toner case detects the number of toners 1 to 1 in the case. A developing device of the type that replenishes toner in a replenishment toner container into a toner case by a toner conveying means when a shortage is detected is also conventionally known. The toner conveyance means is driven by a toner replenishment motor.

[Problem to be solved by the invention]

However, as described above, foreign matter may be mixed into the toner conveyed from the replenishment toner container to the toner case. In such cases, foreign objects may become clogged in the toner transport means.
It may stop its operation. When the toner conveying means stops in this manner, toner is not conveyed to the toner case, and the toner presence detection sensor continues to detect toner shortage, so that the toner replenishment motor continues to be in the on state. For this reason, even though the motor is energized, it remains locked and does not rotate.
There is a risk that the motor may malfunction and break down.

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that eliminates the above-mentioned conventional drawbacks with a simple configuration.

[Means to solve the problem]

In order to achieve the above object, the present invention includes: a replenishment toner container containing replenishment toner; a toner case containing toner for visualizing a #electronic latent image formed on a latent image carrier;
A toner conveyance means for conveying the toner in the replenishment toner container to the toner case, a toner supply roller that drives the conveyance means, a toner presence detection sensor that detects the presence of toner in the toner case, and replenishment by the sensor. a motor on/off control means for operating the toner replenishment motor when it is detected that the toner in the toner container should be replenished into the toner case; a timer for accumulating the operating time of the toner replenishment motor; and a timer whose value is set to a predetermined value. and abnormality handling means for stopping the operation of the toner replenishment motor when the toner presence detection sensor detects that toner should be replenished to the toner case even though the value exceeds the value. Suggest a device.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, a drum-shaped photoreceptor 1, which is an example of the configuration of a latent image carrier, is rotated clockwise in the figure, and at this time, an electrostatic latent image is formed on the photoreceptor 1 in a manner known per se. Ru. This latent image is visualized by a developing device 2 disposed opposite to the photoreceptor 1.

The developing device 2 includes a developing container 3 and a non-magnetic developing sleeve 5 rotatably supported by the container 3 with a portion exposed through an opening 4, and a cylindrical magnet is installed inside the sleeve 5. 6 is fixedly arranged, and the magnet 6 has a magnetic pole S in its circumferential direction.
, N are magnetized.

In this example, a toner supply roller 7 is supported in the middle part of the developer container 3 so as to be freely rotatable in the counterclockwise direction, and the free end side of the toner layer thickness regulating blade 8 is in pressure contact with the curve of the roller rough, and the developer container 3 A scraping member 9 fixed to the inner wall surface is in pressure contact. The base end side of the blade 8 is fixed to the developer container 3.

As mentioned above, the toner supply roller 7 is located in the middle of the developer container 3.
, a toner layer thickness regulating blade 8 and a scraping member 9 are located, and these divide the inside of the developer container 3 into upper and lower parts, the upper space S1 accommodates the toner T, and the lower space S2 contains the toner T.
contains a two-component developer containing toner and carrier.

In this example, the developing container portion that partitions the space Sl is the photoreceptor 1.
It constitutes a toner case 12 containing toner for visualizing the latent image above.

During the development operation, the developing sleeve 5 is rotationally driven in the counterclockwise direction, and at this time, developer is carried on the surface of the developing sleeve 5 by the magnetic force of the magnet 6, and the developer is conveyed in the rotational direction by the rotation of the developing sleeve 5. Doctor Blade 10
The amount of transport is regulated by doctor blade 1
The developer that has passed through 0 reaches the developing area where the photoreceptor 1 and the developing sleeve 5 face each other, where the toner in the developer is electrostatically transferred to the electrostatic latent image formed on the photoreceptor 1. The latent image is visualized. This visible image is transferred to a transfer paper (not shown), and the transferred visible image is fixed onto the transfer paper by a fixing device.

When the developing operation is performed as described above, only the toner in the developer is consumed, so the toner concentration of the developer gradually decreases. Therefore, a reference latent image of the surface potential as a reference is formed outside the visible image area of the photoreceptor 1, and the latent image is visualized by the developing device 2 in the same manner as described above to form the reference image I. is obtained, and its image density is detected by the density detection sensor 11. When it is determined that the image density of the reference image processing is lower than a predetermined value, the toner supply roller 7 is driven counterclockwise in FIG. The toner is carried, regulated by toner layer thickness regulation grade 8, and carried out of the case 12, scraped off from the surface of the toner supply roller rough by the scraping member 9, and supplied into a two-component developer. In this way, the toner used to visualize the electrostatic latent image formed on the photoreceptor 1 is stored in the toner case 12, and when the toner concentration of the two-component developer decreases, the toner is stored in the toner case 12. The toner T in the case 12 is supplied into the developer p, and the toner concentration is kept within a certain range so that a high-quality visible image can always be formed.

As described above, since the toner is sequentially supplied from the toner case 12 into the developer tank, the amount of toner in the toner case 12 is gradually reduced. Here, if the operator replenishes the toner case 12 with toner every time the toner in the toner case 12 runs out, it would place a great burden on the operator. In order to eliminate such defects,
As shown in FIG. 2, the developing device 2 is provided with a replenishment toner container 13 containing a toner container for replenishment, and a toner presence detection sensor 14 is installed at a suitable location in the toner case 12, in the example shown in the upper wall thereof. Fixed location.

As the sensor 14, a so-called vibration type sensor can be used, and when the toner case 12 is full of toner T, the toner T contacts the sensor 14 and turns it on. Toner T in toner case 12
decreases and the toner T no longer contacts the sensor 14,
The sensor 14 turns off and detects that toner should be replenished into the toner case 12. As a result, the toner T1 in the replenishment toner container 13 is transferred to the first toner conveying screw 15.
As will be explained in detail later, the toner case 12
transported to. The first toner conveying screw 15 constitutes an example of a toner conveying means for conveying the toner in the replenishment toner container to the toner case.

The replenishment toner container 13 has a toner discharge pipe 16 , and the discharge pipe 16 is fitted into a connecting pipe 17 of the toner case 12 . In addition, the first toner conveying screw 15 is disposed at the bottom of the replenishment toner container 13 so as to be able to rotate once, and one end side of the shaft 15a of the screw 15 penetrates the left side wall of the replenishment toner container 13. A gear 18 is fixed to the end thereof.

On the other hand, an agitator 19 for stirring the toner T is disposed inside the replenishment toner container 13, and an agitator 19 that agitates the toner T is fixedly supported.
9a is rotatably supported on the left and right walls of the replenishment toner container 13, and a gear 20 is fixed to one end (left end) of the toner container 9a.
No. 8 is connected to the drive. A worm wheel 22 as a drive gear is also provided at the other end (right end) of the shaft 19a.
is fixed, and the wheel 22 meshes with a worm gear 24 fixed to the output shaft of a toner supply motor 23 that drives the first toner conveying screw 15 .

Further, in the developing device shown in FIG. 2, a second toner conveying screw 25 is rotatably supported also at the upper part of the toner case 12, and a gear 26 is fixedly installed at one end of the second toner conveying screw 25. The gear 2G meshes with a drive gear 27 fixed to the shaft of the toner supply roller 7 described above. These gears 26 and 27 are configured to be rotationally driven by a drive motor 28 via a clutch 29.

As described above, when the amount of toner T in the toner case 12 decreases and the sensor 14 detects this, the toner replenishment motor 23 starts operating, and its rotation is controlled by the worm gear 2.
4 and the worm wheel 22 to the shaft 19a, and the agitator 19 rotates. As a result, the toner T1 in the replenishment toner container 13 is stirred and removed. axis 1
The rotation of 9a is transmitted to the first toner conveying screw 15 via gears 20, 21.18, and the screw 15 rotates. As a result, the toner T in the replenishment toner container 13 is transferred to the toner case 1 through the toner discharge pipe 16.
transported to. At this time, as will be explained later, the second toner conveyance screw 25 and the toner supply roller 7 are rotating, and the toner is reliably conveyed into the toner case 12 by the screw 25. Toner case 12
When the toner inside is full, the sensor 14 detects this and the toner replenishment motor 23 is turned off, completing the toner replenishment operation.

Note that the replenishment toner container 13 is connected to the toner case 1 so that the replenishment toner container 13 can be refilled with toner when the toner in the replenishment toner container 13 runs out or becomes less than a predetermined amount.
It is removable from 2. In other words, Figure 3 (
As shown in a), a door 30 is pivotally attached to the front side (left side in the figure) of the copying machine main body 31 so as to be freely openable and closable, and the above-mentioned replenishment toner container 13 is arranged inside the door 30, and the toner case 1 is arranged on the back side of the door 30.
2, that is, the developer container 3 is fixedly arranged.

The replenishment toner container 13 is supported on a support rail 32 that is slidable with respect to the copying machine main body 31.

When the remaining amount of toner in the replenishment toner container 13 becomes low,
A sensor (not shown) attached to the container 13 detects this, and a message to replenish the toner is displayed on the display 33 shown in FIG. 3(a).

In accordance with this, the operator opens the door 30 and
), pull the support rail 32 toward you (to the left in FIGS. 2 and 3) and pull out the replenishment toner container 13 above it. Then, open the upper cover of this container 13, replenish the toner in the toner bottle 34 into the replenishment toner container 13, and after replenishing the replenishment toner container 13, return the replenishment toner container 13 to the copying machine main body 31 as shown in FIG. 3(a). Close the door 30 by pushing it inside.

When the replenishment toner container 13 is set in the copying machine main body as shown in FIG.
The toner case 12 is biased to the right by a compression spring 36 wound around the toner case 12 and hits a stopper 37 attached to the inner wall surface of the toner case 12 .

As shown in FIG. 3(b), when the replenishment toner container 13 is pulled out toward the front, the slide tube 35 is released from the stopper 37, and is therefore pressed by the compression spring 36 as shown in FIG. The cover 38 slides on the toner discharge pipe 16 and comes into contact with a cover 38 fixed to the tip of the shaft 15a of the first toner conveying screw 15. This closes the opening at the tip of the toner discharge pipe 16, and prevents the toner from spilling out from the toner discharge pipe 16. When the replenishment toner container 13 is set in the copying machine main body 31, the slide tube 35 hits the stopper 37, the cover 38 is separated from the slide tube 35, and the opening at the tip of the toner discharge tube 16 is opened.

In the above-mentioned developing device 2, toner is replenished into the toner case 12 by the rotation of the first toner conveying screw 15 as described above. At this time, if foreign matter is mixed in the toner, this may cause the screw to 15.2
5 may get stuck and stop rotating. If this abnormal state is left unattended, the sensor 14 will not detect that the toner is full forever, and the motors 23, 28
Since only the motor 23 remains on, the motor 23
．． There is a risk that 28 will be overloaded and break down.

The present invention eliminates such drawbacks, and the details of its construction and operation will be clarified in addition to the previous description with reference to FIGS. 2 and 5.

First, as mentioned above, when the image density of the reference image ■ shown in FIG.
) is turned off, and at this time the toner supply motor 23 does not operate (FIG. 5(b)).

When the image density of the reference imager falls below a predetermined value, the first
The density detection sensor 11 shown in FIG. 2 and FIG. 2 detects this, and the detection signal is input to the copy sequence control means 39 shown in FIG. 2, and the output from the means 39 turns on the clutch 29.

The rotation of the instant motor 28 is transmitted to the toner supply roller 7 and the second toner transport screw 25 via gears 27,26. As a result, as described above, the toner T in the toner case 12 is transferred to the developer D stored in the space S2 below.
(Fig. 1).

When the clutch 29 is in the on state as described above, it is checked whether the toner presence detection sensor 14 is on or not (FIG. 5(d)). When the sensor 14 is on, that is, when the toner case 12 contains a sufficient amount of toner T, the toner supply motor 23 does not operate (FIG. 5(f)). At this time, only the second toner conveyance screw 25 and the toner supply roller 7 operate.

Note that the timers shown in FIGS. 5(c), (e), and (g) will be explained later.

Next, with the clutch 29 in the ON state, the toner case 12
The toner T1 in the replenishment toner container 13 decreases, the toner presence detection sensor 14 turns off, and the toner T1 in the replenishment toner container 13 decreases.
When it is detected that the toner case 12 should be replenished with
The detection signal is input to the motor on/off control means 40 shown in FIG.
The toner supply motor 23 is immediately activated via the motor driver 41 (FIG. 5(h)). That is, in a state where a command indicating that the clutch 29 is in the on state is inputted from the copy sequence control means 39 to the motor on/off control means 4o, a detection signal for replenishing toner from the sensor 14 is sent to the motor on/off control means 40. When input, the toner replenishing motor 23 starts operating according to the command from the means 40. As a result, the agitator 19 and the first toner conveying screw 15 rotate as described above, and the toner in the replenishment toner container 13 is conveyed to the toner case 12. At this time, since the clutch 29 is also on, the second toner conveyance screw 25 and the toner supply roller 7 are also rotating. That is, while the second toner conveyance screw 25 and the toner supply roller 7 are rotating,
When the sensor 14 detects that toner should be replenished, toner is replenished from the replenishment toner container 13 to the toner case 12 . When the second toner conveyance screw 25 and the toner supply roller 7 are stopped, even if the sensor 14
Even if it detects that toner should be replenished, the first toner conveying screw 15 does not operate. Thereby, it is possible to avoid the possibility that an excessive amount of toner is replenished into the toner case 12.

As described above, at the same time that the toner replenishment motor 23 starts operating, the timer 42 that totals the operating time of the motor 23 starts operating based on the output from the motor on/off control means 40 (FIG. 5(i)).

"Timer off" shown in FIGS. 5(c) and (g) indicates that this timer 42 is turned off, and "rt=0" shown in FIG. ” indicates that it will be returned to.

After the timer 42 is turned on, the comparison and determination means 44 shown in FIG. 2 checks whether the count value of the timer 42 has reached a predetermined value t0 (FIG. 5(j)). Usually, the count value t is a predetermined value t. The clutch 29 is turned off before that and the toner replenishment motor 23 is also turned off (Fig. 5(b), (c)), or even when the clutch 29 remains on, the sensor 14 is turned off. On, that is, it is detected that the toner case 12 is full of toner, and the count value of the timer 42 is returned to "0" (FIG. 5(e)).
Subsequently, the toner supply motor 23 and the timer 42 are turned off by a command from the motor on/off control means 40 (fifth
Figures (f), (g)).

The timer reset determination means 43 in FIG. 2 outputs a command to the timer 42 to return the count value of the timer 42 to "O" in response to the full toner detection signal in the toner case 12 from the sensor 14.

On the other hand, if foreign matter is mixed into the toner being conveyed and this stops the rotation of the first and second toner conveying screws 15.25, the toner case 12 will not be replenished with toner, and the timer 42 will start counting. The value t is the predetermined value t0
The sensor 14 is off even if the toner case 1 is exceeded.
2, it continues to detect that toner should be replenished. In this way, when t>to, an abnormality occurrence signal is output from the comparison/judgment means 44 to the abnormality processing means 45, and the abnormality processing operation is executed by the output from there to the copy sequence control means 39 ( Figure 5(k)).

That is, the output from the copy sequence control means 39 turns off the clutch 29 and the toner supply motor 23, and also turns off the timer. Further, abnormality processing operations such as stopping the copying operation and displaying the fact that an abnormality has occurred on the display 33 are also performed.

With the above-described configuration, even if an abnormality occurs when toner is transferred from the replenishment toner container 13 to the toner container 12, it is possible to prevent a problem in which an excessive load continues to be applied to the motor, and a failure of the motor can be prevented. .

The structure and operation of the embodiment of the present invention have been explained above according to the functional block diagram shown in FIG.
For example, it can be configured by a microcomputer, and FIG. 6 is a schematic configuration diagram of an example thereof. That is,
The CPU 50, which performs the functions of each of the above-mentioned means 39.4.0, 43, 44, and 45, has a built-in timer 42, ROM, and RAM, and detects the detection signals of the density detection sensor 11 and the toner presence detection sensor 14. Each command is input to the CPU 50, and the command from the CPU 50 is sent to the clutch driver 51.
The rotation of the translating motor 28, which is input to the clutch 29 through the CPU 50 and is activated by an ON command from the CPU 50, is transmitted to the toner replenishing roller 7 (FIG. 2).
A command from the toner supply motor 23 is inputted to the toner replenishment motor 23 via the motor driver 41, and the various control operations described in detail above, such as activation of the motor, are executed.

In the illustrated embodiment, a developing device is shown in which the toner in the toner case 12 is supplied while the two-component developer is being used. However, the toner in the toner case is directly used to visualize the electrostatic latent image. It goes without saying that the present invention can also be applied to the one-component developing device used.

[Effects of the Invention] According to the present invention, even when foreign matter is mixed in the toner transported from the replenishment toner container to the toner case, failure of the toner replenishment motor that immediately moves the toner transport means can be prevented. is possible.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the developing device, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, with a functional block diagram added;
3(a) and 3(b) are schematic explanatory diagrams showing the relationship between the replenishment toner container and the copying machine main body, and FIG. 4 is a sectional view showing a configuration for sealing the toner discharge pipe when pulling out the replenishment toner container. FIG. 5 is a flowchart corresponding to the functional block diagram shown in FIG. 2, and FIG. 6 is a block diagram showing a configuration example using a microcomputer. 12... Toner case 13... Replenishment toner container 14... Toner presence detection sensor 23... Toner replenishment motor 40... Motor on/off control means 42... Timer 45... Abnormality processing means T,
T...Tonner Figure 3 Agent Patent Attorney Norio Hoshino-μ

Claims (1)

[Claims] A replenishment toner container containing replenishment toner, a toner case containing toner for visualizing an electrostatic latent image formed on a latent image carrier, and transporting the toner in the replenishment toner container to the toner case. a toner conveyance means for replenishing the replenishment toner container; a toner replenishment motor for driving the conveyance means; a toner presence detection sensor for detecting the presence of toner in the toner case; a motor on/off control means for operating the toner replenishment motor when the toner replenishment motor is detected; a timer for accumulating the operating time of the toner replenishment motor; A developing device comprising: abnormality handling means for stopping the operation of the toner replenishing motor when a presence detection sensor detects that toner should be replenished to the toner case.