JPH05150654A - Toner supply device - Google Patents

Abstract

PURPOSE:To prevent the quality of a copied image from being deteriorated at the time of starting copying after setting up. CONSTITUTION:A toner concentration sensor 40 for detecting toner concentration in developer 10 is provided in a developing part 20. At the time of setting up an image forming device, the developer 10 having reference toner concentration is thrown in a developing tank 21 to adjust so that an output signal from the sensor 40 may become from an L level to an H level. In the midst of being ready before starting copying, a toner motor 36 is driven according to a driving command from a controller 50 so as to rotate a carrying member 35 to supply toner in a toner box 32 in a carrying pipe 31, so that a part which is not filled with the toner in the pipe 31 is eliminated before starting copy. When the toner is supplied in the tank 21, the output signal from the sensor 40 becomes from the H level to the L level. When such change is detected, the controller 50 stops the driving of the toner motor 36. Thereafter, the toner is directly supplied by the amount corresponding to consumption in the developing part 20 when the copying operation is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner supply device installed in a developing unit of an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art Recently, as a developer used in a copying machine, a two-component type developer composed of a toner and a carrier is often used. A developing unit that stores a two-component developer of this type includes a developing tank that stores the developer and supplies the toner in the developer to the photoconductor, and a toner that is consumed as the developing process progresses. Toner is supplied to the developing tank to replenish the toner.

This toner supply device comprises a toner box into which replenishment toner is charged, and a toner supply means for supplying the toner in the toner box into the developing tank through a transport passage. Here, the transport passage is generally formed of an elongated transport pipe, and in a color copying machine, a particularly long transport pipe is used because a plurality of developing tanks are arranged side by side.

In such a copying machine using a two-component type developer, adjustment is made at the time of installation so that the developer having a reference toner concentration is stored in the developing tank. When this adjustment is completed, replenishment toner is put into the toner box, and then the copy operation is started.

[0005]

By the way, when a long and narrow conveying pipe is used as the conveying passage, the toner is not completely supplied to the conveying pipe in a state where the toner is put in the toner box, and a considerable unfilled portion is not formed. Remains.

Therefore, when the user starts up the copying machine and starts the copying operation in such a state, the toner in the developing tank is consumed, the toner concentration in the developer is lowered, and the toner concentration sensor for detecting this is detected. Even if the toner supply device instructs the toner supply device to supply the toner, the toner is not supplied to the developing tank until the inside of the conveying pipe is filled with the toner. As a result, the copy image formed during this period has a low density and the copy image quality is impaired. Such a drawback becomes a particularly serious problem in a color copying machine.

The present invention solves the above-mentioned drawbacks of the prior art, and it is possible to reliably prevent a decrease in toner density at the start of copying after the image forming apparatus is installed, and it is possible to improve copy image quality. An object is to provide a toner supply device.

Another object of the present invention is to prevent malfunction.
An object of the present invention is to provide a toner supply device that can improve reliability.

[0009]

The toner supply device of the present invention is a toner supply device which is provided in an image forming apparatus and supplies replenishment toner into a developing tank containing a two-component developer. A toner storage unit that stores toner to be replenished to the developer, a toner supply unit that replenishes the toner stored in the toner storage unit to the developing tank via a transport passage, and the inside of the developing tank. A toner concentration detecting means for detecting a toner concentration of the toner, and outputting a high level signal when the toner concentration becomes lower than the reference concentration, and outputting a low level signal when the toner concentration becomes higher than the reference concentration, The toner supply unit is driven during operation standby immediately after the toner is put into the empty toner storage unit, and the toner is discharged when the output of the toner concentration sensor changes from the high level to the low level. And control means for stopping the driving of the feeding means, the object is achieved.

Preferably, when the driving of the toner supply means is started during the standby of the operation, the control is performed by shifting the control reference value of the toner density detection means to the under toner side by a predetermined amount.

The toner supply device of the present invention is a toner supply device which is provided in an image forming apparatus and supplies replenishment toner into a developing tank containing a two-component developer. A toner storage unit in which toner to be replenished to the agent is stored, a toner supply unit that supplies the toner stored in the toner storage unit to the developing tank through a transport passage, and the image forming apparatus are installed. When the toner is put into the empty toner storage unit and the toner concentration in the developing tank is adjusted to a reference level, the toner supply unit is driven for a certain time to put the toner in the transport passage. And a control means for filling the same, whereby the above object is achieved.

[0012]

As described above, when the toner supply means is driven during the operation standby immediately after the toner is put into the empty toner storage portion, the toner supply means supplies the toner into the conveying passage. When the image forming apparatus is installed, the toner is reliably supplied to the toner unfilled portion existing in the transport passage. Therefore, when the copying operation is started after that and the toner in the developing tank is consumed, the toner is immediately supplied to the developing tank, so that the problem that the copy image quality is lowered does not occur.

If the output of the toner concentration sensor changes from a high level to a low level, the toner concentration in the developing tank reaches the reference concentration at that time, so that the toner supply means should be stopped at this time. It is good, but the driving time of the toner supply means required until the unfilled part in the transport passage is surely filled is obtained in advance by experiments, etc., and the toner supply means is driven for the determined fixed time. Also, it is possible to reliably prevent a decrease in the density of copy image quality.

Further, at this time, if the control reference value of the toner concentration detecting means is shifted to the under toner side by a predetermined amount, the toner is surely filled to the inside of the conveying passage and supplied to the inside of the developing tank. At this time, since it is possible to more reliably detect the increase in the toner concentration, it is possible to improve the reliability.

[0015]

EXAMPLES The present invention will be described below with reference to examples.

1 and 2 show the entire structure of the toner supply device of the present invention. The toner supply device includes a developing unit 20 in which a two-component developer 10 including toner and carrier is stored.
And a toner supply device main body 30 for supplying toner into the developing section 20. First, the configuration of the developing unit 20 will be described.

The developing section 20 has a developing tank 21 for accommodating the developer 10, and two conveying screws 22, 22 are provided in parallel in the developing tank 21. The conveying screws 22 and 22 convey the toner introduced into the developing tank 21 from the introduction pipe 26 provided at one end side thereof in the rotation axis direction.
The toner carried in the developing tank 21 by the carrying screws 22, 22 is agitated by the two agitating rollers 23, 23 provided in parallel to the lateral sides of the carrying screws 22, 22, and the developer in the developing tank 21 is agitated. Mixed with 10.

The toner mixed with the developer 10 is supplied by the magnet roller 24 to the photosensitive drum 25 which is arranged to face the magnet roller 24 at a predetermined interval. More specifically, an electrostatic latent image is formed on the surface of the photoconductor drum 25, and toner is supplied to the electrostatic latent image in the copying process, so that a toner image is formed.

Since toner is consumed as the copying process progresses, toner for replenishment is supplied from the toner supply device main body 30 to the developing section 20. This replenishment operation is performed by the control device 50 driving the toner motor 36 of the toner supply device main body 30 in accordance with the detection signal of the toner concentration sensor 40 arranged in the developing tank 21.

The toner concentration sensor 40 detects the toner concentration in the developer 10 and outputs a detection signal to the control device 50. More specifically, the toner concentration sensor 40 controls the H level (high level) signal when the toner concentration in the developer 10 is lower than the reference concentration (reference toner concentration) adjusted when the copying machine is installed. Output to 50, and the developer 10
When the toner density inside is higher than the reference density, an L level (low level) signal is output to the control device 50.

The main body 30 of the toner supply device is a long and narrow conveying pipe in which one end side is connected to a toner box 32 and a discharge pipe 34 provided at the lower part of the toner box, and the other end side is connected to the introduction pipe 26. Has 31. A conveying member 35 formed of a coil spring is inserted into the discharge pipe 34 and the conveying pipe 31. One end of the carrying member 35 is connected to a toner motor 36 attached to the back surface of the toner box 32. Further, in the toner box 32, a toner stirring roller 33 for stirring the toner in the toner box and dropping it into the discharge pipe 34.
Are arranged.

With this structure, when the toner agitating roller 33 is rotated and the toner motor 36 is driven, the toner accumulated in the discharge pipe 34 is rotated by the conveying member 35, and the toner is accumulated on the developing portion via the conveying pipe 31. 20 developing tanks 21
The toner is supplied to the inside, and the toner is replenished by this. The drive of the toner motor 36 is controlled by the controller 50 as described above.

By the way, when a copying machine of this type is newly installed, an adjusting operation for setting the toner concentration in the developer 10 housed in the developing tank 21 to the reference concentration is first performed.
When the adjustment work is completed, the toner box 3
Toner for replenishment is put into the unit 2, and then the copy operation is started.

Here, since the conveying pipe 31 is long, the toner is not supplied to the entire area inside the conveying pipe 31 during the operation standby state immediately after the toner is put in, that is, during the so-called ready, and a considerable unfilled portion is present. Exists. Therefore,
When copying is started from this state, the toner in the developer 10 in the state set to the reference density is consumed, and the toner density is lowered, but the toner is not immediately replenished, and the copy caused by this is caused. Image density is reduced. That is, if it is left as it is, the image quality of the copy is deteriorated due to the time lag between the consumption of the toner and the replenishment of the toner.

Therefore, in the present embodiment, in order to prevent such a problem, the toner motor 36 is driven during the ready to pre-fill the unfilled portion in the conveying pipe 31 with the toner, and thereby the toner is discharged. A configuration that eliminates the time lag between consumption and replenishment of toner is adopted.

FIG. 4 shows the control procedure of the controller 50 during the ready. The control device 50 first determines in step S1 whether or not the adjustment work for adjusting the toner concentration in the developer 10 to the reference concentration is completed, and if it is confirmed that the adjustment work is completed, the process proceeds to step S2, in which the toner motor Drive 36.

The adjustment work shown in step S1 is performed as follows. First, the developer 10 having the reference density is stored in the developing tank 21, and then the magnet roller 24, the agitating rollers 23, 23 and the conveying screws 22, 22 are rotated, and the output signal of the toner density sensor 40 changes from L level to H level. Adjust to change to level. At this time, the toner is put into the toner box 32.

When the toner motor 36 is driven in step S2, the toner conveying member 35 is rotated, and the toner falling and accumulated in the discharge pipe 34 starts to be filled in the unfilled portion of the conveying pipe 31.

Next, in step S3, the output signal from the toner density sensor 40 is read and the output state is determined. When it is confirmed in step S3 that the output signal of the toner concentration sensor 40 has changed from the H level to the L level, that is, the unfilled portion in the transport pipe 31 is eliminated, and the toner transported in the transport pipe 31 is developed. When it reaches the inside of the tank 21 and it is confirmed that the toner concentration in the developer 10 has reached the reference concentration, the process proceeds to step S4, where the driving of the toner motor 36 is stopped. Succeedingly, in a step S5, the copying machine is set to a copyable state, and this processing is ended.

After that, when the copying operation is started, the toner is immediately replenished into the developing tank 21 through the conveying pipe 31 without causing a time lag, so that the problem of lowering the density of the copied image does not occur. ..

On the other hand, in step S3, the toner density sensor 4
If it is determined that the output signal of 0 is still at the H level, in this case, it is necessary to continue driving the toner motor 36 to eliminate the unfilled portion in the transport pipe 31, and thus the process returns to step S2. Then, the processes of steps S2 to S3 are repeated.

FIG. 5 shows another embodiment of the present invention. In this embodiment, when the unfilled portion of the transport pipe 31 is eliminated, the level of the control reference value of the toner concentration sensor 40 is shifted to the under toner side, whereby the detection accuracy of the unfilled portion elimination is improved and the reliability is improved. The structure is designed to improve the sex.

In addition, according to this structure, when the output of the toner concentration sensor 40 is adjusted, the toner concentration sensor 4 can be adjusted.
If you forget to output a signal from 0 to H level, or if you make a mistake when you should adjust the output from L level to H level, but change it from H level to L level. In addition, since the H level signal is output from the toner concentration sensor 40, even in such a case, there is an advantage that the unfilled portion in the transport pipe 31 can be reliably eliminated.

The control procedure of the control device 50 in this embodiment will be described below. When it is confirmed in step S10 that the same adjustment work is performed, the control device 50 next shifts the level of the control reference value of the toner density sensor 40 to the under toner side by a predetermined level in step S11. Specifically, the analog output level of the toner concentration sensor 40 is shifted to the under toner side, that is, the H level side by 0.15 V (corresponding to about 0.3 wt% in toner concentration). This shift operation may be performed by a control command from the control device 50 to the toner concentration sensor 40 or may be manually performed.

When the shift operation of the reference density level is completed, next, in step S12, the toner motor 36 is driven to start the operation of eliminating the unfilled portion in the transport pipe 31. Then, in step S13, the output signal from the toner density sensor 40 is read and the output state is determined.

When it is confirmed in step S13 that the output signal of the toner density sensor 40 has changed from the H level to the L level, the toner motor 36 is output in step S14 as described above.
Drive is stopped, the reference density level is returned to the original state in step S15, the copy ready state is set in step S16, and this processing ends.

On the other hand, if it is determined in step S13 that the output signal of the toner concentration sensor 40 is still at the L level, in this case, the process returns to step S12 and the processes of steps S12 to S13 are repeated.

In each of the above-described embodiments, the operation of eliminating the unfilled portion in the conveying pipe 31 is performed by the change of the output signal of the toner concentration sensor 40.
Such a canceling operation can be performed regardless of the output signal of.

That is, from the time when the driving of the toner motor 36 is started to the time when the unfilled portion in the conveying pipe 31 is surely eliminated by an experiment or the like in advance, the measurement is performed during the ready. Fixed time (as an example, the pitch of the transport member 35 = 5.5 mm, the transport member 35
Total length of 220 mm, number of rotations of toner motor 36 = 30
Even if the toner motor 36 is driven only for 55 seconds when the speed is rpm, the unfilled portion in the transport pipe 31 can be surely eliminated, and the copy operation with stable image quality can be performed.

Further, in each of the above embodiments, the case where the present invention is applied to the black-and-white copying machine has been described, but the present invention is not limited to this, and for example, the toner supply device of the color copying machine as shown in FIG. Can be similarly applied. This toner supply device includes a toner supply device main body A for yellow toner, a toner supply device main body B for magenta toner, and a toner supply device main body C for cyan toner. Each of the supply device main bodies A, B, and C has a yellow developing unit 20A,
The combination of the magenta developing unit 20B and the cyan developing unit 20C and the same configuration as in the above embodiment eliminates the delay in the supply of each toner at the start of copying and prevents the deterioration of image quality.

The parts corresponding to those in the above-mentioned embodiment are designated by the same reference numerals, and their detailed description will be omitted.

[0042]

According to the toner supply device of the first aspect of the present invention, the unfilled portion of the toner in the conveying passage through which the replenishing toner is conveyed can be reliably eliminated during the ready operation before the start of copying. When the copying is started, the toner in the developer is consumed, and the toner concentration detecting means detects that the toner concentration is lowered, the toner is immediately replenished. Therefore, the density of the copy image does not decrease at the start of copying, and the copy image quality can be stabilized.

Further, according to the toner supply device of the second aspect, the control reference value of the toner concentration detecting means is shifted to the under toner side when the unfilled portion in the conveying passage is eliminated. Accordingly, the detection accuracy is increased and the reliability is improved.

In particular, according to the toner supply device of the third aspect, since it is only necessary to drive the toner supply means for a predetermined time during the ready, there is an advantage that the system configuration of the control system can be simplified.

[Brief description of drawings]

FIG. 1 is a partially crushed front view showing an embodiment of a toner supply device of the present invention.

FIG. 2 is a partial plan sectional view of the toner supply device shown in FIG.

FIG. 3 is a side sectional view of a toner storage unit.

FIG. 4 is a flowchart showing a control procedure of the control device according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure of a control device according to another embodiment of the present invention.

FIG. 6 is a partially crushed front view showing the structure of a toner supply device installed in a color copying machine.

[Explanation of symbols]

 10 developer 20 developing unit 21 developing tank 24 magnet roller 30 toner supply device body 31 carrier pipe 32 toner box 35 carrier member 36 toner motor 40 toner concentration sensor 50 controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor 23-30 Mizoguchi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Masatoshi Kanekoshi 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Yoshiaki Ochi 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture Within Sharp Corporation

Claims (3)

[Claims] 1. A toner supply device provided in an image forming apparatus for supplying replenishment toner into a developing tank containing a two-component developer, wherein the toner replenished to the developer is stored. And a toner supply unit for replenishing the toner stored in the toner storage unit to the developing tank through a conveying passage, and the toner concentration in the developing tank is detected. When the toner density is lower than the density, a high level signal is output, while when the toner density is higher than the reference density, a low level signal is output, and the toner storage unit in an empty state stores the toner. Control means for driving the toner supply means during operation standby immediately after being turned on, and for stopping the drive of the toner supply means when the output of the toner concentration sensor changes from a high level to a low level. Toner supply device. 2. The toner supply according to claim 1, wherein when the drive of the toner supply means is started during the standby of the operation, the control reference value of the toner density detection means is shifted to the under toner side by a predetermined amount. apparatus. 3. A toner supply device provided in an image forming apparatus for supplying replenishment toner into a developing tank containing a two-component developer, wherein the toner replenished to the developer is stored. Toner storage unit, toner supply means for replenishing the toner stored in the toner storage unit to the developing tank through a transport passage, the image forming apparatus is installed, and the toner storage unit is in an empty state. A control unit for driving the toner supply unit for a certain period of time to fill the toner in the transport passage when the toner concentration is adjusted to the reference concentration and the toner concentration in the developing tank is adjusted to the reference concentration. Toner supply device.