JPS63177163A - Image forming device - Google Patents

Abstract

PURPOSE:To improve operability by providing a storage part which stores a signal supplied through an amplification part according to an initial state storage mode set previously in a developer concentration control means until the initial state storage mode is reset. CONSTITUTION:An arithmetic processing and control part is provided with a memory 64 and the initial state storage mode wherein detection signals for developers by colors and a reference light signal are stored in the memory 64. The detection light signal for the developers by the colors and the reference light signal are stored until the storage contents of a program memory 52 are rewritten in the initial state storage mode set in the memory 52. Therefore, even if both signals are stored every time the concentration of each developer is detected in the initial state storage mode, an initial standard developer concentration value is prevented from varying. Consequently, an automatic developer control system which has superior operability can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION , -1--1 The present invention generally relates to an image forming apparatus, and in particular, for example,
The present invention relates to an image forming apparatus that converts an electrostatic latent image formed on an image carrier by electrophotography or electrostatic recording into a visible image using a two-component developer containing toner and carrier.

1 [
In an image forming apparatus that uses a two-component developer when converting a latent image into a visible image, the quality of the copied image obtained from the apparatus is stabilized and a copied image of good quality is obtained. From the above, it is extremely important to control the developer concentration, which indicates the mixing ratio of toner and carrier forming the two-component developer, to an appropriate ratio.

1-The need for a technical means to control the developer concentration of a two-component developer to an appropriate value as described above is due to the need, for example, when a two-component developer is used for image formation and the developer concentration of the developer is This is particularly large in color image forming apparatuses, which have a large effect on image quality such as image quality and contrast in a completed copy image.

Therefore, in view of these facts, conventional methods have been used to accurately detect the amount of developer in one or more developing devices that house the two-component developer, and to respond to the detection result of the concentration. A color image forming apparatus has been developed that is equipped with a system that strictly controls the toner replenishment tank that is supplied from the outside into the developing device, thereby maintaining the developer concentration in each developing device at a substantially constant level. . FIG. 3 shows a developer concentration detection device of the devices constituting the automatic developer concentration control system in the color image forming apparatus described above. However, the color image forming apparatus equipped with the developer concentration detection device A shown in FIG. It is rotatably supported on a shaft, and yellow (Y), magenta (M
), cyan (C), and black CB), which are in contact with the outer circumferential surface of the photoreceptor drum. The device is equipped with a transfer drum that is rotatably supported at a certain position, and various devices that are arranged around each of these devices.

The outline of the developer concentration detection device shown in FIG. 3 is as follows:
), black (B), and black (B).
The developing device side detection unit 30 is composed of a developing device side detection unit 30 of M, and one developing device external detection unit 40 that is attached to the side plate of the main body of the image forming apparatus at a position that does not come into contact with each of these developing device side detection units 30. be. However, since all of the developing device side detection units 30 are of circular configuration, the unit 30 attached to the developing device 25Y and the developing device external detection unit 40 will be described here. The developer side detection unit) 30 is
As is clear from FIG. 3, the unit support has a substantially delta-shaped longitudinal section and is disposed with a protrusion facing near the upper part of the developing sleeve 251Y provided in the developing device 25Y. and two optical fibers 32.34 attached so as to form a substantially V-shape along the two long sides of the unit support, and these two optical fibers 32.34 are in contact with each other. a reflective mirror 31 disposed near a contact point, and a developing sleeve 25 that cools near a location of the unit support where the reflective mirror 31 is disposed.
A developer concentration detection window 33 is provided at a position facing the outer peripheral surface of the developer. On the other hand, the developing device external detection unit 40 is attached to the image forming apparatus main body at the aforementioned developing position so as to face the developing device side detecting unit 30 of the developing device stopped at the developing position. a support 41 and the optical fiber 3 of the support 41;
A light source 42 attached to a portion facing the end of 2
and an aperture 43 formed in a portion of the support 41 facing the end of the optical fiber 34, and an axial extension connecting the end of the optical fiber 34 and the aperture @43. A light-receiving element 45 such as a photodiode is arranged at a predetermined distance from the support 41, and the light-receiving element 45 is configured to move up and down in the space between the support 41 and the light-receiving element 45. The color separation filter 44 is provided with a solenoid 49 for moving the color separation filter 44 up and down. The above configuration will be described in more detail as follows. That is, the light source 42 is.

White light is emitted as the irradiation light, and the optical fiber 32 receives the white light emitted from the light source 42 and transmits it to the reflecting mirror 31. The reflective mirror 31 is connected to the optical fiber 32.
It receives and reflects the white light transmitted through the 1 to 1 white light, and illuminates the development level detection part 33. Along with this, the reflecting mirror 31 receives the light incident through the developer C degree detection window 33, reflects it, and supplies it to the optical fiber 34. The concentration detection window 33 is composed of a gicroic mirror that reflects the spectral energy light A shown in FIG. Among them, for example, the visible light component having a wavelength of about 700 nm or less is reflected, and the near-infrared light component having a wavelength of about 700 nm or more is transmitted. At the same time, the developer concentration detection window 33 detects a near-infrared light component having a wavelength of about 700 nm or more that passes through the detection window 33, collides with the developer on the developing sleeve 251Y, and is reflected by the developer. The aIIC is used to transmit the light and directly apply it to the reflecting mirror 31 or the optical fiber 34. The optical fiber 34 connects to the reflecting mirror 31 or the developer concentration detection window 33.
receives and transmits a near-infrared light component with a wavelength of approximately 700 nm or more provided through the aperture 43,
The light is applied to the light receiving element 45 via a color separation filter 44. At the same time, the optical fiber 34 does not pass through the guichroic mirror but is reflected on the surface of the guichroic mirror, or the i-light energy light A
is received through the reflecting mirror 31 or directly and is applied to the light receiving element 45 in the same manner as described above. The above-mentioned color separation filter 44 is connected to the light receiving element 4
A filter member 4 having an area sufficient to cover the light receiving portion of No. 5.
7 and a filter member 48 having an area of approximately the same size as the filter member 47 are integrally formed, and the filter member 47 has a filter member 48 that is approximately 700 nm or less reflected on the surface of the guichroic mirror. The filter member 4B transmits only the visible light component having a wavelength of
Only the near-infrared light component with a wavelength of about 700 nm or more transmitted through the mirror is 'I!' ! The near-infrared light component is transmitted to the light receiving element 45 as developer concentration detection light d.
It is designed to be able to be used.

Furthermore, to explain the color separation filter 44 mentioned above, the color separation filter 44 is configured to move up/down in the arrow direction in FIG. 3 by means of a solenoid 49 and a spring (not shown). In the early stage of development, the filter member 47 is arranged along the axis connecting the light receiving part of the light receiving element 45 and the opening part to make the reference light r enter the light receiving element 45, and in the later stage of development, the filter member 47 is arranged along the axis connecting the light receiving part of the light receiving element 45 and the opening part. The filter member 48 is disposed on the axis 1-, which connects the light-receiving portion of the developer and the aperture, and allows the developer concentration detection light d to enter the light-receiving element 45. The aforementioned light receiving element 45
In this case, the developer concentration detection light d whose light amount increases as the developer concentration of each developing unit increases and decreases as the mass image side density decreases is transmitted to the filter member 4.
When the reference light r enters through the filter member 47, an electric signal corresponding to the incident light is output as a developer concentration detection signal, and when the reference light r enters through the filter member 47, an electric signal corresponding to the incident light is output as a developer concentration detection signal. The corresponding electric signal is output as a reference signal for detecting deterioration of the light source 42 and dirt of the detection optical system.

A developer concentration detection signal and a reference signal indicating the developer concentration of each developing device are transmitted from the developer concentration detection device having the above-mentioned configuration to the developer concentration detection signal and the reference signal at the timing shown in FIG. When e times are given to the control system that makes up the eye movement control system, the signal is amplified to a predetermined magnitude in the amplifier circuit that makes up the control system, and then the control system The digital electronic circuit control means of the 1γ1 control system determines the difference value between the two bending signals, and the difference value is recognized as the developer concentration value. , toner replenishment is controlled based on the result of a comparison calculation between the difference value and a developer concentration reference value for each color stored in advance in the control system.

FIG. 4 shows an example of an amplifier circuit used in the control system that constitutes the above-mentioned automatic developer concentration control system.
As is clear from FIG. 4, the above-mentioned first-order width section, which shows the circuit configuration of the second-order width section, is equipped with an operational amplifier that receives the signal output from the light receiving element 45 on the inverting input terminal side. a first stage circuit as a preamplifier; and a second stage as a non-inverting amplifier circuit comprising an operational amplifier different from the operational amplifier that receives an output signal from the operational amplifier of the first stage circuit on the non-inverting input terminal side. It consists of a circuit. The linear term width section outputs a signal P.

However, if an attempt is made to control the developer concentration in each developing device using the automatic developer concentration control system configured as described above, problems as described below will occur. That is, when the developer concentration detection device detects the developer concentration of the developer for each color, the developer concentration detection light d
The reflectance of near-infrared light of approximately 700 nm or more differs for each color developer, and the value of the developer concentration detection signal at the standard developer concentration differs greatly for each color. This is caused by assembly errors and tolerances when assembling the optical fibers 32, 34, reflection mirror 31, etc. in the developing device side detection unit 30, which is installed in each of the plurality of developing devices that individually store the agent. Since the rate of light loss is different for each developer-side detection unit 30, even if the same amount of light is applied from the light source 42 to each of these developer-side detection units 30, The amount of incident light that enters the light-receiving element 45 via the device-side detection unit 30 differs, resulting in large variations in the signals indicating the standard developer concentration detection 1 for each color. As a result, the accuracy of toner replenishment control for each developing device varies, resulting in a problem that the control range of developer concentration differs for each color.

Therefore, in view of these problems, the inventors of the present invention further connected a quadratic term width part having the configuration shown in FIG. 5 after the linear term width part shown in FIG. 4. By doing so, we aim to correct the above problems.

That is, the quadratic term width part of the configuration shown in FIG.
It receives the signal P output from the primary term width section and further amplifies it for each color. It receives the signals corresponding to each developer of yellow, magenta, cyan, and black, and mainly performs amplification, etc. Four stages of operational amplifiers CY, CM, CC, each having the same configuration are connected in cascade to perform signal processing.
CBs are connected in parallel to the output sides of the primary tank width portions, respectively. To explain in more detail the circuit configuration of the amplifying section described above, the amplifying section includes a first stage circuit which is a voltage follower, receives an output signal from the first stage circuit at an inverting input terminal side, and provides negative feedback. 2, which is an inverting amplifier circuit equipped with an operational amplifier to which a variable resistor VR is connected.
The inverter is equipped with an operational amplifier that receives the output signal from the second-stage circuit and the second-stage circuit on the inverting input terminal side, and is connected to the variable resistor VR connected to the power supply side. The circuit includes a three-stage circuit that is an adder circuit, and a fourth-stage circuit that is a voltage follower that receives the output signal from the third-stage circuit.

In the secondary amplification section configured as described above, when the developer concentration detection device shown in FIG. 3 detects the developer concentration of the standard developer for each color, which is set to the same concentration for each color. , as a result of the detection, the signal P2YO corresponding to the yellow developer density detection light d and the signal PIYO corresponding to the yellow developer reference light r are changed to the magenta developer density detection light d. The signal P2M corresponding to
O and the signal PIMO corresponding to the reference light r of the magenta developer, and the signal P2CO corresponding to the density detection light d of the cyan developer and the reference light r of the cyan developer.
Further, the signal Pico corresponding to the signal P2BO corresponding to the density detection light d of the black developer and the signal PIBOII (corresponding to the reference light r of the black developer)
Amplifying units CY, CM, CC,
It will be added to CB. The amplification section CY, CM
.

CC and CB are variable resistors VR of the two-stage 11 circuit, respectively;
By adjusting the variable resistance and VR of the three-stage circuit [1], when the above-mentioned signals are inputted to each of these amplifying sections, the output terminal of each of these amplifying sections 1/-P'
Output signals of the same signal level can be obtained from Y, P'M, P'C, and P'B. By setting the variable resistance VR in each of the amplification sections in this way, P'2YO=P'2M0=P'2CO=P'2B
The signal P'2YO corresponding to the yellow density detection light having the relationship O is output from the output terminal 7-P'Y, and the signal P'2MO corresponding to the magenta density detection light is output from the output terminal -fP.
'From M, signal P' corresponding to the cyan density detection light
2CO is output from the output terminal P'C, and a signal P'2BO corresponding to the black density detection light is output from the output terminal P'B. Similarly, P'1YO=P'1M0=
A signal P'lYO corresponding to the yellow reference light having the relationship P'1CO=P'180 is output from the output terminal P'Y.
The signal P'1MO corresponding to the magenta reference light is output from the output terminal P'M, and the signal P''l corresponding to the cyan reference light is output from the output terminal P'M.
GO. is output from the output terminal P'C, and a signal P'lBO corresponding to the black reference light is output from the output terminal P'B. Each output signal from the secondary amplification section as described above is applied to an input interface 53' of the arithmetic processing/control system of the developer concentration control device having the configuration shown in FIG.

Further, the input interface 53' to the r10 port 54
is input.

When the above-mentioned signal is input to the arithmetic processing/control system of the image-side density control device shown in FIG. Supply control will be carried out. That is, the developing device to be detected is, for example, the developing device 25Y containing yellow developer. Sequence controller lt lower J
11 (referred to as "CPU") 51'' operates according to the sequence programmed in the program memory 52 as shown in FIG. When the signal from the light is amplified through the primary amplification section and the secondary amplification section, the amplified signal (this will be referred to as P'IY) is received and sent to an analog-to-digital converter (hereinafter referred to as A/ through an input interface 53' consisting of a D converter), etc.
Furthermore, the program memory 5 is connected through the I10 port 54'.
2' to a predetermined location.

Next, the CPU 51' selects the filter switching plunger 49.
is activated through I10 port 54' and drive circuit 55. In accordance with this timing, based on the signal from the detection light d from the filter 48, the primary amplification section,
The signal P'2Y after being amplified by the secondary amplification section is stored in a predetermined location in the program memory 52' as described above.

1; Developing device 25Y containing the yellow developer described above
Next, a developing device containing magenta developer,
Regarding the developing device containing the cyan developer and the developing device containing the black developer, the concentration of each developer is detected in the same process as described above. The CPU 51 controls each output terminal P of the front two-stage amplifier section according to the above-described sequence stored in the process memory 52'.
'Y, P'M, P'C, and P'B selectively output each signal as described above, and in the same process as the conventional example described above, the C degree of the developer for each color is calculated. 0 to calculate
For example, as described above, by detecting the developer concentration of the standard developer for each color, which is set to the same density for each color, using the developer concentration signal device described above, for the yellow color, P'2YO, The P'lYO signal is the P'2M01P'1MO signal for magenta, the P'2CO and P'ICO signals are for the cyan color, and the P'2BO and P' for the black color. lB
O signals are output for each color.

P'2YO-P'1YO=D3YO1 P'2M0-P'IMO=03MO1P' 2
CO-P' 1cO=D3co.

If we calculate the difference numerator 1, which is the standard developer concentration signal for each color, by P' 2BO - P' 1BO = D3Bo, then I
r1 The contents mentioned above are empty, 03YO=03MO=D3CO=
It is clear that a D3BO relationship is obtained. Therefore,
As explained in the conventional example, there is no variation in the signal level of the standard developer concentration signal for each color, and as a result, there is no variation in the accuracy of toner replenishment control for each developing device. , the control range of the C degree of the developer for each color is also the same.

As mentioned above, D determined by the CPU 51'
Standard developer concentration signals D3YO, 03M0. D3
CO1D3BOJID3YO=D3MO=D3CO=D
The data is stored in the program memory 52' as data D3'O such that 3BO=D30. Apart from the data 030 indicating the standard developer concentration signal for each color described above, data 030 is stored in the program memory 52' when the concentration of the developer stored in each developer is detected. The signal P'l based on the reference light r and the signal P'2 based on the detection light d are shown for each color as follows. That is, P'l in the developing device containing yellow developer is expressed as P'1. 'Y
I, P'2 in the developing device containing yellow developer is P'Y2, P'l in the developing device containing magenta developer is P'MI, and P'MI is the developing device containing magenta developer. Let P'2 in the developing device be P'M2,
P'l in the developing device containing cyan developer is P
'CI', and P'2 in the developing device containing cyan developer is P'C2.

Let P'l in the developing device containing black developer be P'BI, and P'2 in the developing device containing black developer be P'B2.

The CPU 51' calculates a developer concentration signal of the developer for each color from the data stored in the program memory 52 described above. In other words, the yellow developer concentration signal DY is determined by DY=P'Y2-P'YI, and the magenta developer concentration signal DM is determined by DM=P'M2-P'MI.
Therefore, the cyan developer concentration signal DC is DC=P
Based on 'C2-P'CI, the black developer concentration signal DB is determined by DB=P'B2-P'BI. The CPU 51 stores the developer concentration signal for each color obtained by the above-mentioned calculation and the program memory 52'.
Comparison calculations are made with the standard developer concentration signal value of the developer for each color as described above stored in . To explain this using a yellow developer as an example, when it is determined that DY≧030 as a result of the above comparison calculation, the CPU 51' recognizes that the yellow developer concentration is an appropriate value or is high, and operates the developer 25Y. On the other hand, when it is determined that DY<030, it is recognized that the toner is thin. When it is recognized that the toner is thin, it outputs a drive command signal to the drive circuit 55, thereby driving the hopper drive motor (MY) 57 attached to the hopper 56 in which the yellow toner is stored, starting from the 1γ1 hopper 56 (not shown). Yellow toner is replenished into the developing device 25Y via the joining means. Thereafter, the same signal processing and toner replenishment control as described above are performed for each developer of magenta, cyan, and black color.
) 59, but for cyan toner replenishment, the hopper 60
and hopper drive motor (MC) 61, and for black toner replenishment, hopper 62 and hopper drive motor (MC)
MB) 63 will be involved.

By the way, even in the developer concentration automatic control system with the above-mentioned improved configuration, at the initial standard developer concentration, the eight variable As mentioned above, the resistor VR is D3YO
It is necessary to manually adjust so that =03MO=D3CO=D3BO. Moreover, as is clear from the above-mentioned content, the standard developer concentration signals 03YO, 03M0. D3CO, D3BO and
The eight variable resistors V are set so that the data D30 stored in advance in the program memory 52'
Since it is necessary to set R, it is extremely troublesome to manually adjust the eight variable resistors VR and initialize them again.

Therefore, in view of the above-mentioned facts, the present invention aims to further improve the system mentioned above, and by improving the automatic developer concentration control system, it is possible to The object of the present invention is to provide an image forming apparatus equipped with an automatic developer concentration control system with improved performance.

8. The object of recording images is achieved by the image-forming I& device according to the present invention. In summary, the present invention accommodates an image carrier and a two-component developer each having a toner and a carrier of a different color, and uses the two-component developer to form an image on the image carrier. a developing means for at least two measurement tools for converting the electrostatic latent image formed on the image into a visible image; and determining the concentration of the developer stored in each of the developing means by irradiating each developer with light. a developer concentration detection means that detects by receiving reflected light reflected from each developer; and a developer that controls toner replenishment to each of the development means according to a signal output from the developer concentration detection means. An image forming apparatus comprising a developer concentration control means, wherein the developer concentration control means includes:
The signal level of the output signal after receiving the signal output from the developer concentration detection means for each of the developers and amplifying these signals is the same for each of the developers. an amplification section for amplifying and outputting a signal, and the initial state storage mode is canceled when the signal is applied via the amplification section according to an initial state storage mode set in advance in the developer concentration control means. The image forming apparatus is characterized in that it includes a storage section for storing data up to the present time.

1 pot 1 An embodiment of the present invention will be described below with reference to the drawings.

Figure 2 shows the unreleased 15? An outline of an image forming apparatus according to an embodiment of the present invention is shown in FIG. 2, as shown in FIG. An electrostatic latent image forming section consisting of a supported photoconductor drum 21 and various devices disposed on and near the outer peripheral surface of the photoconductor drum 21; The electrostatic WI image forming section includes a transfer section, and a rotary developing section disposed near the electrostatic WI image forming section.

The electrostatic latent image forming section described above includes the photoreceptor drum 21 and the vicinity of the outer peripheral surface of the photoreceptor drum 21 in the rotational direction of the photoreceptor drum 21 (counterclockwise direction in FIG. 2) ■ From the second stream side to the downstream side Cleaning means 28.
It is equipped with a pre-exposure means 22 and a corona charger 23i.

The transfer section includes a transfer drum 26 which is rotatably supported clockwise in FIG. a transfer corona discharger 27 disposed at a portion where the transfer drum 26 contacts the photoreceptor drum 21 on the inner peripheral side; A separating claw 29 and the like are provided on the downstream side of the transfer drum 26 in the rotational direction. The rotary developing section includes a casing 25 that is rotatably supported in a counterclockwise direction in FIG. The developing devices 25Y, 25M, and 2 are designed to perform development when they reach a position facing the surface.
5C125B and each of these developing devices 25Y, 25M, 25
A developer side detection unit 30 is fixedly disposed on each of C and 25B, and a developing device side detection unit 30 is disposed at a portion where the outer circumferential surface of the housing 25 and the outer circumferential surface of the photoreceptor drum 21 face each other. The developing device external detection unit 40 and the like are provided. The above configuration will be described in more detail as follows. That is, the cleaning means 2B is equipped with a blade A, and is used to scrape and collect toner remaining on the outer peripheral surface of the photoreceptor drum 21. The first stage of pre-exposure 22 is configured to eliminate charges remaining on the outer peripheral surface of the photosensitive drum 21 by being driven. The corona charger 23 uniformly charges the outer peripheral surface of the photoreceptor drum 21 after residual toner is scraped and collected by the cleaning means 28 and residual charges are removed by the pre-exposure means 22. An image exposing means such as a laser beam scanner is attached to the outer peripheral surface of the photoreceptor drum 21 through a gap set on the downstream side of the rotation direction of the photoreceptor drum 21 of the corona charger 23. Image exposure 24 corresponding to the original image information is applied from the image exposure 24, and a color separation latent image is formed by the image exposure 24.
Of B, the developing device 25Y has a yellow two-component developer, the developing device 25M has a magenta two-component developer, and the developing device 25C has a cyan two-component developer. But again.

The developing devices 25B each house a black two-component developer, and develop a color corresponding to the color separation latent image formed on the outer peripheral surface of the photoreceptor drum 21 by rotation of the housing 25. One of the developing devices containing the developer reaches a developing position facing the outer circumferential surface of the photoreceptor drum 21 and stops moving, thereby developing the color separated latent image. Note that details of the above-mentioned developer side detection unit 30 and developer side detection unit 40 will be described later. The aforementioned transfer drum 26 is.

The transfer drum 26 rotates while receiving the transfer material P sent out at a predetermined timing from a pair of registration rollers (not shown) and guided through a transfer material guide member and holding it on the outer peripheral surface of the transfer drum 26. It has become. The transfer corona discharger 27 rotates the transfer drum 26 so that the transfer material P held on the outer circumferential surface of the transfer drum 26 reaches a position where the outer circumferential surface of the transfer drum 26 and the outer circumferential surface of the photoreceptor drum 21 come into contact with each other. At this time, the visible image formed on the outer peripheral surface of the photosensitive drum 21 is transferred onto the transfer material P by performing corona discharge. The separating claw 29 is pivotally supported so as to be able to swing freely in the direction of the arrow in FIG. After separating the transfer material P from the outer peripheral surface of the transfer drum 26 1
It is configured to be sent to a fixing device (not shown).

According to one embodiment of the present invention, each of the developing units 25Y, 25M, and 25C125B of the above-mentioned rotary developing section has one developing unit side detector having the same configuration as a developer concentration detecting means, that is, a developer concentration detecting device. As mentioned above, one developing device external detection unit 40 is disposed in the side plate of the image forming apparatus main body, which is the developing position described above. The configurations of the unit 30 and the outside developing device detection unit 40 are as shown in FIG. 3 of the city record, so the explanation thereof will be omitted.

Further, according to the present invention, there is a developer concentration control device included in an image forming apparatus according to an embodiment of the final IJI.

In addition to the primary amplification section shown in FIG. 4 and the secondary amplification section shown in FIG. The structure is as follows. The outline of the arithmetic processing/control system shown in FIG. 1 is the same as the arithmetic processing/control system shown in FIG.
In addition to the arithmetic processing/control system having the configuration shown in the figure, there is also a storage section, that is, a memory 64, which corresponds to the memory 64, and stores the developer detection signal and reference light signal for each color in the memory at the time of the initial standard developer concentration. 64 is added.

The memory 64 described above is a so-called non-volatile memory that is constantly backed up by a backup power source 65 such as a battery, and its memory contents can be rewritten in the initial state storage mode previously set in the program memory 52. Until this is performed, the developer detection light signal and valley light signal for each color are stored. The memory 64 stores a detection light signal and a reference light signal at the initial standard developer level e for each color.
Yellow developer C degree detection optical signal P”2YO)J
Reference optical information for C and yellow color developer->P”l
Y O is the magenta developer concentration detection optical signal P"2
Reference for YO and the magenta color developer P″IMO
The cyan developer concentration detection optical signal P''2CO and the cyan developer reference optical signal P''IcO are the black developer C concentration detection optical signal P''2BO and the black developer C concentration detection optical signal P''2BO. A developer reference optical signal P″IBO is stored. Furthermore, to explain the reason why the memory 64 as described above is provided in the arithmetic processing/control system according to one embodiment of the present invention, if the memory 64 that is constantly backed up by the backup power supply 65 as described above is not provided, Even if both of the above-mentioned signals are stored each time the concentration of each developer is detected in the initial state storage mode, the previously stored memory contents can be changed by cutting off the drive power of the image forming apparatus main body. Therefore, if the developer concentration in the developing device changes every time the concentration is detected, the so-called initial standard developer concentration value described above will change every time the concentration is detected. Therefore, it becomes impossible to always control the developer concentration at a specific developer concentration value.

1- In the configuration described above, each output signal obtained from the primary amplification section shown in FIG. 4 and the secondary amplification section shown in FIG. It is supplied to the human power interface 53 of the arithmetic processing/control system of the developer concentration control device, and further from the input interface 53
The data is stored at a predetermined address in the program memory 52 via the 10 port 54. The reference light r stored in a predetermined address in the program memory 52 in this way
The signal P"l based on the detection light d and the signal P"2 based on the detection light d are shown for each color as follows.

Detection light d signal Reference light R signal Yellow developer p ″2 Y P
″′IY′IY Magenta color P ″2 M
P ” IM cyan developer P ”
2 CP ” IC black color developer P ”
2BP''I The BCPU 51 calculates the developer concentration signal of the developer for each color from the data as described above stored in the program memory 52. That is.

The yellow developer concentration signal D Y is D Y =P
"2 Y - P" By Y, the magenta developer concentration signal D"M is D"M=P"2M-P"1M
Accordingly, the cyan developer concentration value D ” CIf,
According to D″C=P″2C−P″lc, the black developer concentration signal D″B is obtained by D″B=P″2B−P″IB. Along with this, the CPU 51
From the data stored in the memory 64 as described above, an initial standard developer concentration signal of the developer for each color is calculated. That is, the yellow initial standard developer concentration signal D
"Y0 is D"YO=P"2YO-P"IYO, and magenta color initial standard developer concentration signal D"MO is D"YO=P"2YO-P"IYO.
By ``MO=P''2M0-P#IMO, the cyan color initial standard developer concentration signal D''CO is DCO=P''
2CO-P"1CO, the initial standard developer concentration signal D"BO for black color is D"BO=P"2BO-P"
180 respectively. The CPU 51 compares and calculates the developer concentration signal of the developer for each color as described above with the initial standard developer concentration signal of the developer for each color. To explain this using yellow developer as an example,
When it is determined that D″Y≧D″YO as a result of the comparison calculation, the CPU 51 recognizes that the yellow developer concentration is an appropriate value or is high, and does not replenish toner into the developing device 25Y.

On the other hand, when it is determined that D"Y<D"YO, it is recognized as B. And when I realized that it was thin,
A drive command signal is output to the drive circuit 55.

As a result, the hopper 5 in which the yellow toner is stored
By driving a hopper drive motor (MY) 57 attached to 6, yellow toner is replenished from the hopper 56 into the developing device 25Y via a junction F stage (not shown). Thereafter, the same signal processing and toner replenishment control as described above are performed for each developer of magenta, cyan, and black.
and a hopper drive motor (MM) 59, and a hopper 60 and a hopper drive motor (MC) for cyan toner replenishment.
61, and a hopper 62 and a hopper drive motor (MB) 63 are respectively involved in replenishing black toner. The initial state storage mode is set by manually operating a mode start switch (not shown).

In this embodiment, an optical density detection device using near-infrared light is adopted as the developer concentration detection device.
In the present invention, in addition to the above-mentioned type of device, for example, a method of detecting in the visible light range and a detection optical system of this type may be adopted, or a different type of device may be adopted. Furthermore, the circuit configurations of the primary tank width section, the secondary tank width section, and the arithmetic processing control system are not limited to those described above. However, it is not limited to only 4 colors, but 2 colors, 3 colors, and 5 colors.
The present invention can be applied to color or more color devices or black and white image format I&Sc systems, and the developing device is not limited to the so-called rotary type, but can of course be applied to stationary type.

As explained above, according to the present invention, an image forming apparatus equipped with an automatic developer concentration control system with improved operability is provided by improving the automatic developer concentration control system. can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the configuration of an arithmetic processing/control system of a developer concentration control device included in an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a partial vertical sectional view showing the configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing the structure of a developer concentration detection device used in an image forming apparatus according to an embodiment of the present invention and a conventional image forming apparatus. FIG. 4 is a circuit diagram of a primary tank width section provided in an image forming apparatus according to an embodiment of the present invention and a conventional image forming apparatus, respectively. FIG. 5 is a circuit diagram of a secondary tank width section provided in an image forming apparatus according to an embodiment of the present invention and a conventional image forming apparatus, respectively. FIG. 6 is a timing chart of driving various devices including signals output from the device shown in FIG. 3. FIG. 7 is a block diagram showing the configuration of an arithmetic processing/control system of a developer concentration control device A provided in a conventional image forming apparatus. 21: Photosensitive drums 25Y, 25M, 25C125B: Developing device 30: Developing device side detection unit 40: Developing device side detection unit 51: CPU (sequence controller) 52 Niprogram memory 64: Memory 65: Backup power supply CY, CM, CC, CB: Amplification section (secondary amplification section) Agent Patent attorney Akira Kura Tachibana Zo 20, Clean IF of the drawing (no change in content) Fig. 1 Fig. 2 Copper 6 Fig. #I47 [-continued supplement! r old (method) % formula%

Claims (1)

[Scope of Claims] 1) An image bearing member and a two-component developer each having a different color of toner and a carrier are housed, and the two-component developer is used to form an image on the image bearing member. at least two developing means for converting an electrostatic latent image formed into a visible image; and irradiating each of the developers with light to determine the concentration of the developer stored in each of the developing means. a developer concentration detection means for detecting by receiving reflected light reflected from the developer; and controlling toner replenishment to each of the development means in accordance with a signal output from the developer concentration detection means. An image forming apparatus comprising a developer concentration control means, wherein the developer concentration control means receives signals output from the developer concentration detection means for each of the developer and amplifies these signals. An amplification unit is provided for amplifying and outputting each of the signals so that the signal level of the subsequent output signal is the same for each of the developers, and is set in advance in the developer concentration control means. An image forming apparatus comprising: a storage section that stores a signal applied via the amplification section according to an initial state storage mode until the initial state storage mode is canceled. 2) The developer concentration detecting means includes a detection optical system having a light emitting means and a light receiving element means that outputs an electric signal according to the amount of light received, and the developer concentration detecting means is irradiated by the light emitting means and stored in each of the developing means. The light-receiving element means receives the reflected light reflected by the developer, and receives an electric signal indicating the developer concentration value from the reflected light and an electric signal indicating the developer concentration value caused by the detection optical system. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to output a reference electric signal for correcting an error occurring in the signal from each of the light receiving element means. 3) The amplification section includes a primary amplification section that receives and amplifies both the signals output from the developer concentration detection means;
The secondary amplifying section is provided with a secondary amplifying section connected to the output side of the secondary amplifying section, and the secondary amplifying section is configured to control each of the developers outputted from the light receiving element means at an initial standard developer concentration. A standard developer concentration signal and a reference signal corresponding to the amount of light reflected from the developer are received for each developer, and after amplifying these signals, the signal level of the output signal is the same for each developer. The image forming apparatus according to claim 1 or 2, wherein the image forming apparatus is configured to amplify and output each signal to a signal level.