JPH0293568A - Method for controlling replenishment of toner for developing device - Google Patents

Abstract

PURPOSE:To optimally control the replenishment of toner by integrating on/off pulse signals which change corresponding to the change of toner concentration and starting or stopping the driving of a toner replenishing mechanism when the integrated value reaches a reference integrated value. CONSTITUTION:The toner replenished from a toner replenishing roller 7 is stirred and mixed and, at the same time, a detection output is outputted every rotation from a toner concentration sensor 10 side every time a stirring member 8 turns to a specified rotating position with the signal of an angle position detection sensor 21. After the ON pulse signal oscillated every time the toner concentration in a developer container 1 is equal to or under(above) the optimum reference value reaches a certain integrated value or a certain pulse width, a toner replenishing action is started and continued until the OFF pulse signal reaches a certain integrated value or a certain pulse width. Thus, the replenishment of the toner can be smoothly and optimally controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a toner supply control method for a two-component developer consisting of a carrier and a toner.

"Prior Art" A developing device using a two-component developer consisting of, for example, a carrier and a toner has been known, and in this type of developing device, toner is supplied to a developing container containing the developer at a predetermined mixing ratio. The toner containers are connected via a mechanism, and a toner concentration sensor is disposed inside the developer container to measure the mixing ratio of the toner and carrier that occurs each time the toner is consumed from the developer container by a predetermined electrophotographic development operation. The change is detected by a toner concentration sensor, and the toner replenishing mechanism is driven and controlled based on the detection signal to sequentially supply toner from the toner container into the developer container, but the developer is not circulated. Sometimes, specifically, when toner is supplied from a toner container when the developing roller etc. stops rotating, the toner is supplied unevenly to a part of the developing container, resulting in uneven toner concentration in the developer. as a result, the image density tends to be disturbed.

In order to eliminate this drawback, Japanese Utility Model Publication No. 83-12353 discloses a developing device in which the toner supply mechanism is driven by the logical product of the fact that the developer is being circulated and the fact that the toner concentration of the developer has decreased. We are proposing a device.

``Problem to be Solved by the Invention'' Now, the method for detecting the toner concentration includes changes in the inductance of the developer consisting of toner and carrier, changes in the electrical resistance, changes in the volume of the developer, etc. A method of detecting toner concentration using The toner is always in an agitated state in order to achieve uniform mixing and charge injection, and the replenishment request signal output from the toner concentration detection sensor during the circulation of the toner to achieve this formation is not necessarily constant, and it has been confirmed that there are large fluctuations vertically. has been done.

Therefore, it is known that the replenishment request signal from the toner concentration sensor during the developer circulation is not a continuous ON or OFF signal but an intermittent pulse signal until reaching a predetermined lower limit or upper limit range.

Therefore, if the drive control of the toner replenishing mechanism is performed based on the intermittent pulse signals, ON/Off in a very short time.
F control will be repeated, which will significantly shorten the life of the motor and increase the starting load, leading to an increase in power consumption.

Further, in order to perform the intermittent drive control smoothly, a normal DC motor has poor followability, and as a result, an expensive stepping motor is used, leading to an increase in costs.

In order to solve this problem, it is possible to configure the toner concentration sensor to output a signal after the toner concentration reaches a predetermined lower limit or upper limit, but this would abandon the optimal toner replenishment control. This leads to the image being distorted, making it impossible to provide high-quality images.

In view of the drawbacks of the prior art, the present invention provides R
It is an object of the present invention to provide a toner replenishment control method that can perform toner replenishment control smoothly and optimally without having to perform constant or unnecessary intermittent control on a motor.

"Means for Solving the Problem" Now, since the detection output from the toner concentration detection means, which changes in response to changes in toner concentration during developer circulation, fluctuates due to stirring in the developer container, for example, The detection output becomes a waveform component as shown in FIG. 3A (a).

Therefore, by comparing the waveform component with the optimum reference level OL, the pulse width can be changed in response to changes in toner concentration.
N/OFF pulse signal (hereinafter referred to as the first pulse signal)
However, in order to obtain a configuration in which a pulse signal is generated unless the lower limit value of the waveform component exceeds the optimum reference level CL in the signal, for example, a WAND gate circuit etc. is used. A correction pulse signal (hereinafter referred to as a second pulse signal) may be obtained by removing a pulse width corresponding to an optimum reference level CL or higher from the pulse signal. For example, the third
As shown in Figure B, the angular position of the rotating stirring member is detected, and based on the detection signal, the toner concentration detection output at a predetermined rotational position of the stirring member is intermittently (every - rotation) output (
d), and converts the detection output into an ON/OFF pulse signal (hereinafter referred to as 3rd signal) using a pulse width modulation circuit.
By generating (e) a pulse signal (hereinafter referred to as "pulse signal"), it is possible to obtain an ON/OFF pulse signal whose pulse width changes in proportion to the difference between the optimum reference level OL and the detection output while removing variable elements.

The first feature of the invention described in claim (2) is that an ON/OFF pulse signal that changes in response to a change in toner density during developer circulation is first prepared.

The second feature is that while the pulse width of the ON or OFF state of the signal is integrated, a comparator, a judgment circuit, etc., determines whether the integrated value has reached the reference integrated value. Includes both addition and subtraction.

Incidentally, since the second and third pulse signals are generated only when the pulse width is below the optimum reference level CL, the pulse width ai is simply integrated as shown in the first equation.
It is possible to judge whether the integrated value has reached the reference integrated value A, but since the first pulse signal is output even at the optimum reference concentration level or higher, the pulse width 1 is simply set in this state.
．． If the toner density is integrated, the integrated value will be added even if the toner density is higher than the optimum reference density. Therefore, it is necessary to correct the pulse signal to a second pulse signal in advance, or use the method shown in the second equation below. It is only necessary to subtract the pulse width aχ corresponding to the optimum reference concentration level by the number of integrations n, and determine whether the subtraction-corrected integrated value has reached the reference integrated value A.

A≦(al +−・−+ aL) ...1) A≦[(
a'l -1-m+a'4 ) -nXa')(] -
2) The third feature is that when the integrated value reaches the reference integrated value, the drive of the toner replenishing mechanism that replenishes toner into the developing device is started or stopped based on the comparative output of the comparator or the like. The point is to do the following.

Note that the invention described in claim 1) has the trouble of having to select arithmetic expressions 1) and 2) depending on the type of pulse as described above.

Therefore, the invention as set forth in claim 2) provides for the following: when the pulse width a1 of the ON/OFF Hals signal that changes in response to the change in toner concentration during the developer circulation becomes equal to or less than a certain pulse width A°, This problem is solved by determining the toner replenishment mechanism using a comparator or the like, and starting or stopping the drive of the toner replenishment mechanism that replenishes the toner into the developing device based on the comparative output of the comparator or the like. .

A°≦ai...3) "Function" In each of the above inventions, for example, an ON (OFF) signal is oscillated each time the toner concentration in the developer container falls below (or above) the optimum reference value or the reference sphere. Instead of repeating the start and stop of toner replenishment intermittently based on the pulse signal, for example, the O
The toner replenishment operation is started after the N pulse signal reaches a certain integrated value or a certain pulse width, and after the replenishment operation has started, the toner replenishing operation is stopped until the OFF pulse signal reaches a certain integrated value or a certain pulse width. Since the toner replenishment operation continues until the OFF pulse signal reaches a certain integrated value or a certain pulse width without any problem, so-called batch-like replenishment control at predetermined time intervals is possible.

As a result, even a normal motor can follow the motor sufficiently, and the trouble of frequent replenishment can be avoided, so the starting load and power consumption can be significantly reduced, and the motor life can be significantly extended.

Furthermore, since the present invention performs so-called zone control such as integrating pulse signals, it is possible to substantially eliminate various noise factors contained in individual pulse signals, and as a result, it is possible to eliminate replenishment unlike the prior art described above. It is possible to create a car that performs toner replenishment control with substantially stable accuracy without any fluctuations in accuracy.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. It's nothing more than that.

FIG. 1 shows the internal structure of a developing device according to an embodiment of the present invention.To briefly explain the mechanical structure, 1 is a developing container containing carrier and toner at a predetermined concentration ratio, and a photosensitive drum is shown in FIG. A mag roll (not shown) is contained on the opening side facing the developer container 3, and supports a developing roller 4 connected to a main motor 11 (to be described later), and is placed above the developer container 1.

The toner container 2 is attached via the partition plate 5.

And on the bottom side of the tapered guide recess 6 formed at an arbitrary location on the partition plate 5? A toner replenishment roller 7 covered with sponge is rotatably attached to the opening 6a, and a DC motor 12 whose drive is controlled based on a control circuit to be described later is connected to the opening 6a. do.

On the other hand, inside the developer container 1, an agitation member 8 configured to be rotatable in synchronization with the development roller 4 and an angular position detection sensor 21 are installed concentrically with the agitation member 8, approximately at the center thereof. While circulating the toner and carrier (hereinafter referred to as developer) in the container by the rotation of 21, each time the stirring member 8 rotates to a predetermined rotational position, an output permission signal is sent to the toner concentration sensor 10 provided on the bottom side of the container 1 below the stirring member 8, and based on the permission signal, the stirring member 8 The toner concentration sensor lO at a predetermined rotational position outputs a detection output every rotation.

Next, the circuit configuration for performing the toner replenishment control will be explained. Reference numerals 22 and 23 are a pulse width modulation circuit and a reference voltage generator corresponding to the optimum reference level CL, and as shown in FIG. 3B, the stirring member 8 When the detection output from the toner level sensor lO output every rotation at a predetermined rotational angle position becomes below the optimum reference level CL, an ON/OFF pulse signal having a pulse width proportional to the voltage difference is integrated. It is configured to output to the circuit 14 side.

Reference numeral 13 denotes a drive control circuit for the main motor 11, which drives and controls the main motor 11 that rotates/stops the developing roller 4 and stirring member 8 in synchronization with the developing/non-developing operation, and sends the drive signal to the integrating circuit 14. Send to the side.

The integration circuit 14 is operated only when a drive signal is output from the drive control circuit 13, that is, when the developing roller 4 is rotating (
O output from the sensor lO only during developer circulation)
The ON or OFF pulse width of the N/OFF pulse signal is cumulatively counted based on a predetermined clock.
An integration memory 14a that integrates the N pulse width and an integration memory 14b that integrates the OFF pulse width are built in, and each time the integrated value of one memory reaches the integration reference integrated value, an inverted signal is output from the integration determination circuit 15. Based on this, the integrated value is cleared and integration in the other integration memory is started. That is, the integrating circuit 14 is configured to alternately integrate the ON pulse width and the OFF pulse width each time the reference integrated value is reached.

16 is the integration base I of ON pulse width and OFF pulse width, respectively.
! A reference memory circuit in which s integrated values A and B are stored, 1
8 is a DC motor drive control circuit 13, and an integration determination circuit 15.
Based on the inversion signal output from the DC motor 12, a drive start or stop signal for the DC motor 12 is output.

Next, the operation of this embodiment will be explained in detail based on the time chart shown in FIG. 2. First, when the developing roller 4 and stirring member 8 are rotating (during developer circulation) by the drive of the main motor 11. In (2), the detection output of the toner concentration sensor 10 detects the change in toner density while being stirred by the stirring member 8;
0, a detection output is output to the pulse width modulation circuit 22 at each predetermined rotation angle position/rotation of the stirring member 8, as shown in FIG. 3B.

The pulse width modulation circuit 22 outputs an ON/OFF pulse signal having a pulse width proportional to the voltage difference to the integration circuit 14 side when the detection output becomes equal to or less than the optimum reference level CL. On the other hand, the ON pulse width a is multiplied by -1 by ANDing with the drive signal from the main motor drive control circuit 13.

During this period, the rotation of the DC motor 12 is stopped, and the integration is determined when the integration value (al +...+ai) reaches the integration reference integration value A, in other words, when it falls below the toner replenishment lower limit value. The circuit 15 determines this by -1, outputs an inverted signal to the DC motor drive control circuit 18,
As a result, the toner supply roller 7 is supplied via the DC motor 12.
is driven, and a predetermined toner replenishment operation is started.

Then, with the start of the toner replenishment operation, on the integration circuit 14 side, the integration ■-2 of the OFF pulse duration is started, and when the integration value (tz +...+bi) reaches the integration reference integration value B, When the toner replenishment upper limit value has been reached, the integration determination circuit 15 determines this as -2 and outputs an inversion signal to the DC motor drive control circuit 18, thereby causing the DC motor 12 to supply the specified toner. Replenishment operation is stopped.

Thereafter, the above operation is repeated.

Note that when the amount of toner in the developer container l falls below the toner replenishment lower limit value or when the toner replenishment upper limit value is reached, the ON or OFF pulse width a can be estimated in advance, so the pulse width ai bL itself is integrated by the integration circuit 14, and when the pulse width aLb becomes greater than or equal to a predetermined reference value A'B', this is determined by the integration determination circuit 15,
By outputting the inversion signal to the DC motor 12 drive control circuit 18 side, a predetermined toner replenishment operation can be started or stopped via the DC motor 12.

"Effects of the Invention" As described above, according to the present invention, it is possible to perform toner replenishment control smoothly and optimally without being limited to the type of motor, and without unnecessary intermittent control of the motor. Since the complexity of replenishment can be avoided, the starting load and power consumption can be significantly reduced, and the motor life can be greatly extended.

Furthermore, since the present invention does not perform replenishment control for each individual pulse, but uses so-called zone control, it is possible to substantially eliminate various noise factors contained in individual pulse signals, and as a result, replenishment accuracy can be improved. However, toner replenishment control can be performed with substantially stable accuracy without any fluctuations.

It has various effects such as

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a developing device according to an embodiment of the present invention, and FIG. 2 is a time chart thereof. FIGS. 3A and 3B are time charts showing the procedure for generating pulse signals used in the embodiment. Figure 1 Figure 3A Figure 3B

Claims (1)

[Claims] 1) A toner replenishment control method for a developing device that performs development while circulating a developer consisting of carrier and toner, wherein O changes in response to changes in toner concentration during the developer circulation.
Toner replenishment for a developing device characterized by integrating N/OFF pulse signals and starting or stopping driving of a toner replenishing mechanism that replenishes toner into the developing device when the integrated value reaches a reference integrated value. Control method 2) In a toner replenishment control method for a developing device that performs development while circulating a developer consisting of carrier and toner, O changes in response to changes in toner concentration during the developer circulation.
A toner replenishment control method for a developing device, comprising starting or stopping driving of a toner replenishing mechanism that replenishes toner into the developing device when an N/OFF pulse signal becomes equal to or less than a certain pulse width.