JPH08137238A - Image forming device, and developing device therefor and controlling method for toner concentration - Google Patents

Abstract

PURPOSE: To realize exact control of the concentration of toner even if users carry out no initialization by making the developing device itself hold the data showing whether the developing device is fresh or not and the reference signal inherent to the developing device for controlling the concentration of toner. CONSTITUTION: The developing device identifying data of the EEPROM8 provided in the developing device 6 in the initial state shows that the developing device is fresh. When the power source of the image forming device is made on after the developing device 6 is loaded, the microcomputer system confirms the working condition of the developing device 6 in compliance with the control procedure of the CPU1. If the device 6 is fresh, it agitates the developer for a specified period by means of a screw. And immediately before the agitation of the developer is finished, a toner sensor 7 detects the toner concentration of the new toner to produce a reference signal by A/D-converting the detected toner concentration and to rewrite the developing device identifying data stored in the EEPROM8 and the output data of the toner sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer using electrophotography, a developing device therefor, and a toner density control method. The present invention relates to a method and apparatus for enabling good toner density control by utilizing stored data indicating the usage state of the developing apparatus and a reference signal for toner density control unique to the developing apparatus.

[0002]

2. Description of the Related Art A conventional image forming apparatus detects a toner concentration of a developer in a developing device which is detachably mounted on the image forming apparatus by a toner sensor provided in the developing device.
The toner density control is performed based on the detected output signal and the toner density control reference signal stored in the image forming apparatus (see Japanese Patent Laid-Open No. 3-105373).

In such a conventional toner density control method,
When the power of the image forming apparatus is turned on, the output signal of the toner sensor is detected before driving the screw for stirring the developer, and it is determined whether or not the developing apparatus is unused.

Further, when the developing device is not used, the output signal of the toner sensor is converted by an A / D converter, and the converted digital data is used as a reference signal for toner density control.

[0005]

According to the above-mentioned conventional toner density control method, in order to make a copy with different colors, when the toner is exchanged with the developing device in which the color of the toner which is already in use is different, The user of the forming apparatus must perform an initialization operation for storing the replaced toner density control reference signal unique to the developing apparatus in the image forming apparatus.

Further, if the user does not perform the above-described initialization operation, the reference signal of the previous developing device remains in the image forming apparatus, so that there is a problem in that accurate toner control cannot be performed.

The present invention has been made in order to solve the above problems, and provides a toner density control method and apparatus which eliminates the initialization operation conventionally required by the user of the image forming apparatus. With the goal.

[0008]

In order to achieve the above object, a developing device of the present invention comprises a toner concentration detecting means for detecting the toner concentration of a developer containing a carrier and toner,
It is characterized in that it is provided with a use state storage means for storing data indicating whether or not the developing device is unused, and a reference signal storage means for storing a reference signal for controlling the toner density.

Further, in the image forming apparatus of the present invention, in the image forming apparatus in which the developing device is detachably mounted, it is determined whether the developing device is unused by reading the data stored in the use state storing means. A usage condition determining means for
Data rewriting means for rewriting the data stored in the usage status storage means to data indicating that the development apparatus is not unused when the usage status determination means determines that the development apparatus is unused; Signal conversion means for A / D converting the output signal from the means, and the A / D converted data as a reference signal for controlling the toner density when the developing device is determined to be unused It is characterized by comprising a reference signal writing means for writing to the signal storage means and a data reading means for reading the data stored in the reference signal storage means.

The toner concentration control method of the present invention is
In a method for controlling a toner density of an image forming apparatus equipped with the developing device detachably, a first step of reading data stored in the usage state storing means, and the developing device based on the data read by the first step. A second step of determining whether or not it is unused, a third step of A / D converting the output signal from the toner density detecting means when the developing device is determined to be unused in the second step, A fourth step of storing the A / D converted data in the three steps in the reference signal storage means, and a fifth step of rewriting the data stored in the use state storage means into data indicating that the developing device is not unused. And a sixth step of reading the data stored in the reference signal storage means.

[0011]

In the developing device of the present invention, the toner density detecting means detects the toner density of the developer containing the carrier and the toner, and the usage status storing means stores data indicating whether or not the developing device is unused. The reference signal storage means stores the reference signal for controlling the toner density.

In the image forming apparatus of the present invention,
The usage status determining means reads the data stored in the usage status storage means to determine whether the developing device is unused, and the data rewriting means determines when the usage status determining means determines that the developing device is unused. In addition, the data stored in the usage state storage means is rewritten to data indicating that the developing device is not unused, and the signal conversion means performs A / D conversion of the output signal from the toner density detection means and writes a reference signal. The means writes the A / D converted data to the reference signal storage means as a reference signal for controlling the toner density, and the data reading means reads the data stored in the reference signal storage means.

In the toner density control method of the present invention, the first step reads the data stored in the use state storage means, and the second step uses the data read in the first step to perform the development. It is determined whether or not the apparatus is unused, and the third step is to perform A / D conversion of the output signal from the toner density detecting means when the developing apparatus is determined to be unused in the second step, and a fourth step In the step, the data A / D converted in the third step is stored in the reference signal storage means, and in the fifth step, the data stored in the use state storage means is already used by the developing device. The data stored in the reference signal storage means is read out in the sixth step.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of essential parts of a control device for controlling an image forming apparatus according to the present invention.

The image forming apparatus is controlled by a microcomputer system including a central processing unit (hereinafter referred to as "CPU") 1 having a built-in A / D converter, and the microcomputer system includes a CPU.
1, a ROM 2 connected to the CPU 1 for storing a control program, and a RAM 3 having a plurality of flag areas necessary for control and temporarily storing data and the like during control by the CPU 1. , An I / O interface 4 for controlling input / output between the CPU 1 and an external device 5 (including a key input circuit, a display circuit, a main motor, a paper supply solenoid, a resist solenoid, a high voltage generation circuit, etc.). .

A toner sensor 7 provided in the developing device 6 is connected to the port P0 of the CPU 1, and an output from the toner sensor 7 is digitized by an A / D converter incorporated in the CPU 1.

A non-volatile, electrically rewritable EEPROM 8 provided in the developing device 6 is connected to the ports P1 to P4 of the CPU 1.
The EEPROM 8 may be a non-volatile storage element capable of electrically rewriting data, and may be a RAM backed up by an external power source such as a battery.

A toner motor 9 provided in the developing device 6 is connected to the port P5 of the CPU1.
Controls ON / OFF of the toner motor 9 via the port P5.

FIG. 2 is a diagram showing the internal structure of the EEPROM 8.

The address ADR0 stores developing device identification data for identifying whether the developing device is unused. For example, if the developing device is unused,
Write'FFh 'to address ADR0 in advance,
And once the developing device is used, the address AD
'00h' is written in R0.

The developing device identification data written in the address ADR0 only needs to be able to identify whether the developing device is unused or not. Therefore, as described above, in particular, "FFh".
And is not limited to '00h'.

As described with reference to FIG. 1, the address ADR1 stores toner sensor output data from the toner sensor 7 digitized by the built-in A / D converter of the CPU 1.

In the present invention, the address ADR
The data areas after 2 are not used but can be used as a general memory. For example, the history of use of the developing device can be stored for history management.

Next, the structure of the developing device detachably mounted on the image forming apparatus will be described.

FIG. 3 is a cross-sectional view of essential parts of the developing device according to the present invention in an unused state.

The developing device 6 is provided with a toner box 19 for storing the toner 18, and the toner 18 is supplied to the developing box 13 by a toner replenishing roller 15.

Further, in the developing device 6, a developer storing portion 11 for storing a developer 10 which is unused and which is composed of carrier and toner mixed with a predetermined toner concentration in order to obtain a reference signal for toner concentration control. Is provided, and the developing device 6
Before the developer is used, the developer storage unit 11 has the film 12
Is separated from the developing box 13.

In the developing box 13, a screw 14 for stirring the developer 10, a toner sensor 7 for detecting the toner concentration of the developer 10, and a photosensitive member used for the image formation of the stirred developer 10 ( (Not shown) and a doctor blade 1 for controlling the amount of the developer 10 conveyed to the photoconductor and the magnet roller 16 for conveying to the photoconductor.
7 is provided.

Next, the operation of mounting the unused developing device having the above-described structure on the image forming apparatus will be described.

Before using the developing device 6 for the first time, the film 12 is peeled off, and the developer 10 stored in the developer storing portion 11 is dropped into the developing box 13.

The unused developing device 6 is mounted and used in the image forming apparatus. In this initial state, the developing device identification data of the EEPROM (not shown) provided in the developing device 6 is: It indicates that the developing device 6 is not used, and the toner sensor output data is data that has no meaning in controlling the toner density.

When the image forming apparatus is powered on after mounting the developing device 6, the microcomputer system shown in FIG. 1 confirms the use state of the developing device 6 according to the control procedure of the CPU 1 described later, and if When the device 6 is unused, the screw 14 stirs the developer 10 for a predetermined time.

Immediately before the stirring of the developer 10 is completed, the toner concentration of the developer 10 used for the first time is detected by the toner sensor 7, and the detected toner concentration is A /
The D conversion is performed to generate the reference signal, and the developing device identification data and the toner sensor output data stored in the EEPROM are rewritten.

As described above, since the control signal for controlling the toner concentration is prepared by measuring the developer having the predetermined concentration by the actual toner sensor 7 for monitoring the toner concentration, the sensitivity of the toner sensor 7 varies. Even if the detection output fluctuates due to, the desired toner density control can be performed.

When the developing device 6 is used, the toner 18 is consumed by the photoconductor, so that the toner concentration of the developer 10 in the developing box 13 is lowered. The toner sensor 7 detects the lowered toner concentration and compares the toner concentration with the reference signal to replenish the toner 18 as a control signal of the toner concentration control system to maintain the toner concentration in the developing box 13 at a predetermined level. ing.

Next, the control procedure of the CPU 1 of the microcomputer system configured as described above will be described with reference to FIG.

FIG. 4 shows E provided in the developing device according to the present invention.
6 is a flowchart showing a procedure for rewriting developing device identification data and toner sensor output data of an EPROM.

When the developing device 6 is attached to the image forming apparatus and the power is turned on, the CPU 1 has an E built in the developing device.
The data of the address ADR0 of the EPROM 8 is read (S100), and the read data is'FFh '.
It is determined whether or not (S101).

The data of the address ADR0 is'FFh '.
If so, the developing device 6 is determined to be unused, and the developer 10 is stirred for a certain period of time so that the carrier and the toner are uniformly mixed (S102).

Immediately before the end of the stirring, the toner sensor 7
Is read from the port P1 and A / D converted inside the CPU 1 (S103), and the A / D converted data is written to the address ADR1 of the EEPROM 8 (S104).

Then, the address ADR of the EEPROM 8
0 is written as "00h" to store that the developing device 6 is not unused (S105), the data written in the address ADR1 of the EEPROM 8 is read, and the data is used as the reference signal of the toner density control system (S10).
6).

If the data at the address ADR0 is "00h" in step 101, it can be determined that the developing device 6 is not in use. In that case, the process jumps to step 106 to write to the address 1 of the EEPROM 8. The obtained data is used as a reference signal for the toner density control system.

[0044]

As described above, according to the present invention, since the developing device itself holds the data as to whether or not the developing device is unused and the reference signal for the toner density control peculiar to the developing device,
The image forming apparatus can control the toner density based on those data and signals.

Further, there is an effect that the user of the image forming apparatus can realize accurate toner density control without performing the initialization operation of the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a control device that controls an image forming apparatus according to the present invention.

FIG. 2 is a diagram showing an internal configuration of an EEPROM according to the present invention.

FIG. 3 is a cross-sectional view of essential parts of the developing device in an unused state according to the present invention.

FIG. 4 is a flowchart showing a procedure for rewriting data in an EPROM included in the developing device according to the present invention.

[Explanation of symbols]

 1 CPU 6 Developing Device 7 Toner Sensor 8 EEPROM 10 Developer 18 Toner

Claims (3)

[Claims] 1. A toner concentration detecting means for detecting a toner concentration of a developer containing a carrier and a toner in a developing device detachably mounted on an image forming apparatus, and data indicating whether or not the developing device is unused. And a reference signal storage unit for storing a reference signal for controlling the toner density. 2. An image forming apparatus in which the developing device according to claim 1 is removably mounted, and a use state in which data stored in the use state storage means is read to determine whether the developing device is unused. And a data rewriting unit that rewrites the data stored in the usage state storage unit into data indicating that the developing device is not unused when the usage state determination unit determines that the development device is unused. A signal converting unit for A / D converting an output signal from the toner density detecting unit, and the A / D unit when the developing device is determined to be unused.
A reference signal writing unit that writes the converted data to the reference signal storage unit as a reference signal for controlling the toner density; and a data reading unit that reads the data stored in the reference signal storage unit. Image forming apparatus. 3. A method for controlling toner density of an image forming apparatus equipped with the developing device according to claim 1 in a detachable manner.
Step, a second step of determining whether or not the developing device is unused from the data read in the first step, and the toner density detection when the developing device is determined to be unused in the second step. The output signal from the means is A / D
A third step of converting, a fourth step of storing the A / D converted data in the third step in the reference signal storage means, and the data stored in the use state storage means being not unused by the developing device And a sixth step of reading the data stored in the reference signal storage means, the toner concentration control method.