JP2002244424A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the developer concentration level by suppressing the variation in toner replenished quantity when a developing device is replenished with the toner from a hopper. SOLUTION: In the device, 2 types of tables which are a table utilized when an image forming device is initially installed and a table utilized in a normal copying sequence are provided as toner replenishing tables utilized when determining the quantity of the toner to be replenished from the hopper 901 to the developing device 4 and the toner replenishing is carried out by using the table that is appropriate when the replenishing ratio is mutually different.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus such as a copying machine or a printer, and has a feature in controlling a toner density in a developing unit.

[0002]

2. Description of the Related Art In a conventional color image forming apparatus for forming a full-color image or a multi-color image, a two-component developer mainly composed of toner particles and carrier particles is mainly used. In the two-component developer, toner particles are consumed during development, and the toner concentration changes. Therefore, a toner concentration detecting means (toner concentration sensor) for detecting the toner concentration of the two-component developer in the developing device, which is a developing means, and toner supply to the developing device in accordance with a toner concentration signal from the toner concentration sensor. A developer concentration control device including a control unit is provided to keep the toner concentration of the two-component developer constant.

As a conventional color toner density control method, for example, a method of measuring and controlling the toner density of a developing device operating during printing from a toner density sensor directly mounted in the developing device, a so-called optical ATR ( Auto Toner
Regulation) method.

In this optical ATR method, a photoelectric detection method is used as a toner density sensor, and reflected light (near infrared light) when light is emitted from a LED as a light emitting element to a developer on a developing cylinder of a developing device. Is detected by the photodiode of the light receiving element, and toner is supplied according to a difference from the initial value. This is based on the property that the carrier (iron) in the developer absorbs near-infrared light while the paint or toner in the developer reflects near-infrared light.

That is, as the amount of toner in the developer decreases, the near-infrared reflected light from the developer also decreases. Conversely, as the amount of toner increases, the near-infrared reflected light also increases. Since there is a correlation between the reflected light and the toner density, it is possible to calculate the toner density at that time based on the reflected light quantity by knowing in advance the relationship between the reflected light quantity and the toner density. is there.

In each toner density sensor, in addition to the photodiode for detecting the toner density, there is a photodiode for detecting the direct light of the LED and generating a reference signal. The change of the output value due to the temperature change of the element is corrected.

Further, there is a so-called patch ATR method in which a toner density sensor disposed in a photosensitive drum unit measures the density of each color toner image developed on a photosensitive drum as an image carrier and controls the toner density. In this patch ATR method, the toner density sensor is of a photoelectric detection type similarly to the color toner density sensor in the above-described developing device, and reflects the reflected light when the toner image on the photosensitive drum is irradiated with light from the LED of the light emitting element. It is detected by the photodiode of the light receiving element. For example, each color toner of magenta M, cyan C, and yellow Y reflects near-infrared light emitted by the LED,
When the black BK toner has a property of absorbing near-infrared light, the reflectance of each of the M, C, and Y toners and the BK toner is based on the reflectance of the photosensitive drum, and BK toner <photosensitive drum <M, C , And Y, and the density of each of the M, C, and Y toners and the BK toner on the photosensitive drum can be measured using this characteristic.

In each toner density sensor, there is a photodiode which detects a direct light of the LED and generates a reference signal in addition to a photodiode which detects the toner density.
As in the case of the optical ATR method, the output value due to the temperature change of the light emitting element and the light receiving element is corrected using this reference signal.

In short, an electrostatic latent image of a detection mark (hereinafter, referred to as a “patch”) is formed on a photosensitive drum, the patch latent image is developed with a toner component of a predetermined color, and the patch is developed from the patch. The density data is detected, the detected density development data is compared with a predetermined value, and a feedback control of the toner adhesion amount in the developing process is performed, so that the toner density in the developing device is controlled within a certain range.

[0010]

In the above-described optical ATR control and patch ATR control, a difference between a value read by a sensor for each color and a target level of each color is obtained, and a density variation value (= ΔD) of the developer is calculated. calculate. From the density fluctuation value, the toner is supplied from a hopper (hopper means) containing the toner to the developing device through a replenishment parameter for obtaining a toner replenishment rate defined by the paper size, that is, a toner replenishment table. At this time, the connection time of the toner supply clutch for opening the toner supply port of the hopper is determined and the toner is supplied. During the copying operation, the toner supply table normally uses one toner supply table for each color.

Incidentally, the unit supply amount of toner supplied from the hopper to the developing device changes depending on the remaining amount of toner in the hopper or the leaving time of toner. For example, when the amount of toner remaining in the hopper is large, the amount of toner flowing out of the toner supply port located at the lower part of the hopper is increased due to the pressure of the toner, as compared with the case where the amount of toner remaining is small.

[0012] Further, if the standing time of the toner in the hopper becomes longer, the toner is collected (solidified), so that the replenishment rate is reduced as compared with the case where the leaving time is short. The supply rate increases because the amount of toner flowing out increases. For example, at the time of factory shipment, the hopper is not filled with toner and is empty, and the empty hopper is filled with toner when the apparatus is installed. After filling the toner, the developer is usually initialized after being left for several tens of minutes.In this state, the toner particles are not solidified, and the initial toner supply rate from the hopper is Significantly increased compared to the case of toner supply into the hopper.

Since the above-described toner supply table has only one table used during the normal copy sequence, the supply rate at the time of initial setting of the apparatus, the supply rate during the normal copy sequence, and the remaining toner In some cases, the difference in the replenishment rate depending on the amount is extremely large, and there is a problem that the toner replenishment amount is not stable.

Accordingly, an object of the present invention is to stabilize the developer concentration by suppressing the variation in the amount of toner replenishment when replenishing toner from the hopper means to the developing means irrespective of the initial installation of the apparatus and the normal copy sequence. An object of the present invention is to provide an image forming apparatus capable of achieving image formation.

Another object of the present invention is to provide an image forming apparatus which can stabilize the developer concentration by suppressing the variation in the amount of toner supplied when the toner is supplied from the hopper to the developing means in a normal sequence. To provide.

[0016]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
An image forming apparatus comprising: an image carrier on which a latent image is formed; developing means for containing a developer containing toner and developing the latent image with toner; and hopper means for supplying toner to the developing means. A toner density detecting means for detecting a toner density in the developing means, a toner remaining quantity detecting means for detecting a remaining toner quantity in the hopper means, and a density fluctuation of the developer from density data detected by the toner density detecting means. Calculating means for calculating a toner supply amount through a first supply parameter and a second supply table for calculating a toner supply amount to be supplied from the hopper unit to the developing unit; and the first supply unit Switching means for switching between the use of the parameter and the second supply parameter, and the switching means for selecting the supply parameter is selected. In this case, the setting of the switching unit is canceled when the remaining amount of toner in the hopper detected by the toner remaining amount detecting unit reaches a predetermined level by using the first supply parameter. An image forming apparatus is controlled so as to use two supply parameters.

According to one embodiment of the present invention, the first supply parameter is used at the time of initial installation of the image forming apparatus,
The second supply parameter is used during a normal sequence.

According to another aspect of the present invention, an image carrier on which a latent image is formed, developing means for containing a developer containing toner and developing the latent image with toner, and supplying toner to the developing means A toner concentration detecting means for detecting a toner concentration in the developing means, a toner remaining amount detecting means for detecting a remaining toner amount in the hopper means, and the toner concentration detecting means. Calculates a density fluctuation value of the developer from the detected density data, and determines a toner supply amount through a first supply parameter and a second supply parameter for determining a toner supply amount supplied from the hopper unit to the developing unit. Calculating means for determining the remaining toner amount until the remaining toner amount detecting means detects that the remaining toner amount has reached the replenishment parameter switching level. Using said first replenishment parameters, after detecting that reaches the switching level image forming apparatus characterized by using said second supply parameters are provided.

According to another aspect of the present invention, an image carrier on which a latent image is formed, developing means for containing a developer containing toner and developing the latent image with toner, and supplying toner to the developing means A toner concentration detecting means for detecting a toner concentration in the developing means, a toner remaining amount detecting means for detecting a remaining toner amount in the hopper means, and the toner concentration detecting means. Calculating a density fluctuation value of the developer from the density data detected by the first step and the initial density data, and determining a toner supply amount for supplying the density fluctuation value of the developer from the hopper means to the developing means. Calculating means for determining the toner supply amount through the first, second, and third supply parameters; and switching means for switching use of the first, second, and third supply parameters. When the switching means for selecting the replenishment parameter is set, the first replenishment parameter is used, the switching means is set, and the detection is performed by the toner remaining amount detecting means. When the remaining amount of toner in the hopper has reached a first remaining level, the setting of the switching unit is released, the third supply parameter is used, and the setting of the switching unit is released. Wherein when the remaining amount of toner in the hopper detected by the toner remaining amount detecting means reaches a second remaining amount level, control is performed so as to use the second supply parameter. Is provided.

According to one embodiment of the present invention, the first supply parameter is used at the time of initial installation of the image forming apparatus,
The second replenishment parameter is used when the remaining amount of toner in the hopper means is less than or equal to a second remaining amount level in a normal sequence, and the third replenishment parameter is used in the hopper means in a normal sequence. Is used when the remaining amount of toner is higher than the second remaining amount level.

According to one embodiment of each of the above inventions,
Furthermore, it has an operation part, and the switching means is set and released via the operation part.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a digital color copying machine as an embodiment of the image forming apparatus according to the present invention.

This color copier includes a digital color image reader unit (hereinafter, referred to as a "reader unit") 201 at an upper part, an image processing unit 203 below the digital color image reader unit, and a printer unit 202 further below the image processing unit 203.

Referring to FIG. 1, an automatic document feeder (RDF) 400 as a document feeder is adapted to transfer a placed document to one document.
The sheets are fed one by one to a predetermined position on the platen glass surface 31. The original 30 is placed on the platen glass surface 31 by the original feeding device 400.
Is fed and placed, the scanner 32 reciprocates in a predetermined direction and collects the original reflected light by the lens 33 via the mirrors 32a, 32b and 32c to the full color sensor 34 integrally formed with the RGB three-color separation filter. It illuminates and a color-separated image analog signal is obtained.

The obtained color-separated image analog signal is
The signal is converted into a corresponding digital signal through an amplifier circuit (not shown), subjected to necessary image processing by an image processing unit 203, and then sent to a printer unit 202.

In the printer section 202, the photosensitive drum 1 as an image carrier is rotatably supported in the direction of the arrow in the figure, and the pre-exposure lamp 11,
Corona charger 2, laser exposure optical system 3, potential sensor 1
2, 4 developing devices (developing means) 4y, 4c, 4m, 4B
k, an on-drum light amount detection sensor 13, a transfer device 5, and a cleaning device 6 are arranged.

In the laser exposure optical system 3, the reader unit 2
01 is converted into an optical signal by a laser output unit (not shown), and the converted laser light is
After being reflected by a, the light is projected on the surface of the photosensitive drum 1 through the lens 3b and the mirror 3c.

When an image is formed by the printer unit 202,
The photosensitive drum 1 is rotated in the direction of the arrow in the drawing, the surface of the drum is neutralized by the pre-exposure lamp 11, and then uniformly charged by the corona charger 2 to irradiate a light image E for each separation color to form a latent image. Form.

Next, a predetermined developing device is operated to develop the latent image on the photosensitive drum 1 to form a resin-based toner image on the photosensitive drum 1. Developing units 4y, 4c, 4m,
In the case of 4Bk, the operation of the eccentric cams 24y, 24c, 24m, and 24Bk causes the photosensitive drum 1 to approach the photosensitive drum 1 in accordance with each separation color.

The developed toner image on the photosensitive drum 1 is stored in a recording material cassette 7a, 7b, 7c, an intermediate tray 2
2, or the recording material 7 supplied from the manual feed tray 7m to the position facing the photosensitive drum 1 via the transfer system and the transfer device 5.
Is transferred to

The transfer device 5 of this embodiment has a transfer drum 5a as a recording material holding means, a transfer charger 5b, an adsorption charger 5c for electrostatically adsorbing the recording material 7, and faces the adsorption charger 5c. A recording material carrying sheet made of a dielectric material, that is, a transfer sheet 5f, is provided in a peripheral opening area of a transfer drum 5a which has a suction roller 5g, an inner charger 5d, and an outer charger 5e and is rotatably supported. Are integrally extended in a cylindrical shape.

As the transfer drum 5a rotates, the toner image on the photosensitive drum 1 is transferred by the transfer charger 5b onto the recording material 7 carried on the transfer sheet 5f.

The desired color image is transferred to the recording material 7 sucked and conveyed to the transfer sheet 5f in this manner, and a full-color image is formed. In the case of full-color image formation, the recording material 7 on which the transfer of the toner images of the four colors is completed is transferred from the transfer drum 5a to the transfer sheet 5 by the action of the separation claw 8a, the separation push-up roller 8b, and the separation charger 5h.
f, the toner image is fixed via a heat roller fixing device (hereinafter, referred to as “fixing device”) 9, and is discharged onto a tray 10.

The fixing unit 9 includes a fixing roller 9a having a built-in heater 9e, a pressure roller 9b having a built-in heater 9f, and a fixing roller 9a, which abut on the fixing roller 9a to apply pressure to the toner image on the recording material 7. An oil application device 9d for supplying a release agent to the roller, a roller cleaning device 9c for cleaning the fixing roller 9a, and each roller 9
a, upper and lower thermistors 78 for detecting the surface temperatures of 9a and 9b
1, 782 (see FIG. 2).

On the other hand, after the transfer, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned by the cleaning device 6.

When an image is formed on both sides of the recording material 7, the recording material 7 formed on one surface is discharged from the fixing device 9, and then the transport path switching guide 19 is immediately driven to drive the recording material 7. Once to the transport path 20 and then the reversing roller 2
1b, the intermediate tray 2 is retracted in a direction opposite to the direction in which the sheet is fed, with the rear end of the sheet being sent in the leading direction.
Store in 2. Thereafter, an image is formed on the other surface again by the above-described image forming step.

The recording material supporting sheet 5 of the transfer drum 5a
f to prevent the powder from scattering and adhering to the recording material 7 on the recording material 7.
, A fur brush 14 and a fur backup brush 15 facing each other, an oil cleaning roller 16 and an oil cleaning backup brush 17 facing each other via the recording material carrying sheet 5f, and a polishing roller 18 facing the furthest via the recording material carrying sheet 5f. And polishing roller backup brush 19
Clean using.

Such cleaning is performed before or after the image formation, or at any time when a jam (paper jam) occurs. In this embodiment, the eccentric cam 25 is operated at a desired timing, and is operated with the cam follower 5i integrated with the transfer drum 5a.
The gap between the recording material carrying sheet 5f and the photosensitive drum 1 can be arbitrarily set. For example, during standby or when the power is off, the transfer drum 5a and the photosensitive drum 1
Are spaced apart.

FIG. 2 is a block diagram showing the configuration of a control system in the color copying machine of this embodiment.

The color copying machine of this embodiment is roughly divided into two blocks for control. One is mainly the leader unit 20
1 and a reader controller 700 for controlling the image processing unit 203, and the other is a printer controller 701 for controlling the printer unit 202.

The reader controller 700 has an optical drive motor driver 7 for driving an optical motor (not shown) for moving the scanning mirrors 32a to 32c and the exposure lamp 32.
02, automatic document feeder (RD
F) RDF controller 70 for controlling 400
3. an operation unit 704 for setting an operation mode of the color image forming apparatus; a ROM 705 storing a control program of the reader controller 700; a RAM 706 storing data such as control values;
And the like are connected to an I / O 706 for driving a load. The RAM 706 is powered up by a battery so that data can be retained even when the power is turned off.

Next, the peripheral control unit of the printer controller 701 will be described.

The printer controller 701 has a ROM for storing a control program for the printer controller 701.
750, RAM 75 for storing data such as control values
1. A / A that converts analog signals from the potential sensor 12 and the on-drum light amount detection sensor 13 into digital data
The D / A converter 752 is connected to a D / A converter 753 that outputs an analog signal set value to the high-voltage controller 770, an I / O 754 that drives loads such as a motor and a clutch, and a sorter controller 708 that controls a sorter.

The reader controller 700 and the printer controller 701 are connected to each other.
Each of them is also connected via the image processing unit 203.
The image processing unit 203 is connected to the laser driver 110.

Further, the printer controller 701 operates as follows:
Fixing thermistor 781 via D converter 752,
It is connected to the lower fixing thermistor 782, the potential sensor 12, the temperature sensor 783, the humidity sensor 784, and the density detection sensor 785 on the surface of the photosensitive drum, and via the D / A converter 783, the high-voltage controller 770 and the developer density It is connected to the detection unit 780, and further connected to the photosensitive drum motor driver 760, the fixing drive motor driver 761, and the main motor driver 762 via the I / O 754.

Next, the toner density control of this embodiment will be described.

In this embodiment, the control by the patch ATR method is applied to the BK toner, and the control of the composite system combining the optical ATR method and the patch ATR method is applied to each of the M, C, and Y toners. I have.

In this embodiment, the M, C, and Y developing units 4
The paints and toners of the developers m, 4c, and 4y reflect the near-infrared light emitted by the above-mentioned LED, and the carrier (iron) has a property of absorbing the near-infrared light.
That is, also in this embodiment, as the toner in the developer decreases, the near-infrared reflected light from the developer also decreases. Therefore, in the optical ATR control, the toner supply amount can be determined from this difference. Further, a method of performing patch development at a rate of once every several times of image formation on the photosensitive drum to detect the actual developer concentration, and correcting this value by performing feedback control on the value of the optical ATR. Has taken.

On the other hand, the BK toner in this embodiment is M, C,
Unlike the Y toner, the near-infrared light emitted by the LED is absorbed, so that even if the near-infrared light is directly applied to the developer, the toner amount in the developer cannot be detected. Therefore BK
Is not an optical ATR control method.
Only TR control is applied.

[Configuration of Optical ATR Sensor] As shown in FIG. 3, in this embodiment, the light A
The TR sensor 50 is attached to the developing device 4 at a position facing the developing cylinder 40. The optical ATR sensor 50 is
As shown in FIG. 4, the LE of a light-emitting element that emits near-infrared light
D51, a first photodiode 53 of the first light receiving element for directly receiving the light via the reflection mirror 52, and a second photodiode of the second light receiving element for receiving the light reflected by the developing cylinder 40.
And the direct light received by the second photodiode 54 is supplied to the developer concentration signal (SI
G). At this time, the light receiving signal of the first photodiode 53 is used as a reference signal (REF).
The output value due to the temperature change of the LED 51 and the second photodiode 54 is corrected.

Similarly, as shown in FIG. 5, a patch ATR sensor 6 as a toner density detecting means in this embodiment.
Reference numeral 0 denotes a patch 58 which is a toner image for density detection developed on the photosensitive drum 1 or an undeveloped portion, which is irradiated with near-infrared light from the LED 61 in the patch ATR sensor 60 and reflected by the first photodiode. Light is received at 62.
In addition, in order to generate a reference signal, the direct emission of the LED 61 is set to the second
The light is received by the photodiode 63.

As described above, in this embodiment, the optical AT
Using the developer density signal and the reference signal detected by the R sensor 50 and the patch ATR sensor 60, the amount of toner to be supplied to the developing device is calculated by a method described later.

[Principle of ATR Control] Next, the principle of ATR control in this embodiment will be described with reference to FIG.

FIG. 6 shows the temperature characteristics of the reflection signal and the reference signal detected by the photoelectric optical ATR sensor and the patch ATR sensor for the M, C, and Y toners.

First, at the time of ATR initial adjustment, the output values of the reflected light of the LED and the direct light (reference light) are respectively represented by V _sig-ini ,
Backup as V _ref-ini . At the time of the initial adjustment, the T / C ratio of the toner (mixing ratio of toner particles / carrier particles) has a correct value, and the temperature characteristic of the reflected light at the correct T / C ratio corresponds to b in the figure. The temperature characteristic a of the direct light has a linear relationship of a = k ′ × b, and the ratio k ′ between a and b is constant regardless of the temperature.

Next, at the time of ATR control, that is, at the time of toner supply, the T / C ratio is different from that at the time of the initial adjustment, and the temperature characteristic is c.
Has changed. Here, also between a and c, c = k ′ × a
And the ratio k ′ between a and c is constant regardless of the temperature.

In addition, T / T in temperature conversion at the time of the initial adjustment of the ATR.
The C ratio variation value corresponds to ΔV. Therefore, when replenishing toner
Output values of reflected light and direct light_sig-now, V
_{ref-n ow}If a / c = k '= const
Therefore, A / B = A '/ B'.

Therefore, V _ref-ini / (V _sig-ini -ΔV)
= V _ref-now / V _sig-now and ΔV = V _sig-ini −V _ref-ini × (V _sig-now / V _ref-now ) (1) is obtained.

That is, from the difference between the reflection signal at the time of the initial adjustment and the value obtained by correcting the current reflection signal, the toner supply amount is determined using this ΔV, and the determined predetermined amount of toner is supplied. In addition, the toner concentration of the developer can be kept constant.

The BK toner has the opposite toner characteristics to those of the M, C, and Y toners.
The equation is as follows: ΔV = V _ref-ini × (V _sig-now / V _ref-now ) −V _sig-ini (2)

Note that the patch ATR
The light receiving window of the TR sensor 60 has become dirty with floating toner.
Therefore, to use the signal level as an appropriate value,
Correction is required. If this correction value is α, (signal
P- as a suffix to distinguish patch signals
ΔV = V for M, C, and Y toners_p-sig-ini-V_p-ref-ini× (V_p-sig-now/ V_p-ref-now) × (1 / α) (3) In the case of BK toner, ΔV = V_p-ref-ini× (V_p-sig-now/ V_p-ref-now) × (1 / α) −V_{p-sig-i ni} ... (4)

The calculation of the correction value α is performed in the developing device
Initial setting / installation was performed in the initial setting process of
The reflected light signal of the photosensitive drum (D
_{SIG-IN I}) And the direct optical signal (= reference signal, D_REF-INI)
And the current reflected light signal of the photosensitive drum measured at the start of copying.
No. (D_SIG-NOW) And the reference signal (D_REF-NOW)
The signal from the sensor is corrected appropriately using the following formula.

Correction value α = (D _SIG-INI / D _SIG-NOW ) × (D _REF-NOW / D _REF-INI ) (5) Next, the mechanism of toner supply from the hopper to the developing device is shown in FIG. This will be described with reference to FIG.

FIG. 7 is a schematic view of the hopper unit 900 as viewed from the front. The hopper unit 900 includes a magenta hopper 901M, a cyan hopper 901C, a yellow hopper 901Y, and a black hopper 901BK that store toners of respective colors of M, C, Y, and BK. Since the basic configuration is the same for each hopper, the configuration of the yellow hopper will be described here as a representative.

FIG. 8 shows an overview of the yellow hopper 901Y. In the hopper 901Y, a toner remaining amount sensor 902Y, a toner supply clutch 903Y, a toner stirring screw 904Y, a toner supply screw 905Y, which is a toner remaining amount detecting means for detecting the remaining amount of toner.
It comprises an eccentric cam 907Y and a one-way arm 908Y. Although only one toner remaining amount sensor is shown in the drawing, this toner remaining amount sensor is installed at a plurality of positions as needed to detect the toner remaining amount level.

When the copying operation is started, the developing units 4y, 4c, 4m, and 4Bk are moved to the positions where they come into contact with the photosensitive drum 1 at a predetermined timing, and the developing operation is started for each color. FIG. 9 shows the developing units 4m, 4c, 4 for each color.
This shows the relative positional relationship with the hopper unit 900 when y and 4Bk are at the developing position.
As shown in the drawing, for example, when the yellow developing device 4y is at the developing position, the toner receiving port 401Y of the developing device 4y is located to face the toner supply port 909Y of the hopper 901Y. The other developing units 4c, 4m, and 4Bk are in the same state.

When the developing operation is started, a hopper motor (not shown) is driven, and the idler gear 906 (see FIG. 7) is rotated by the driving of the hopper motor.
In this state, when the toner replenishment time t is determined according to the ATR control described later, by connecting the toner replenishment clutch 903Y for t time, the driving of the idler gear 906 is transmitted through the eccentric cam 907Y and the one-way arm 908Y, and the toner stirring screw 904Y is driven. , Toner supply screw 9
As the 05Y rotates, toner is supplied from the hopper 901Y to the developing device 4y via the toner supply port 909Y. When the supply for the time t is completed, the drive from the hopper motor is stopped by disconnecting the toner supply clutch 903Y. After that, the developing operation is terminated, and the developing device 4
y moves from the contact position of the photosensitive drum 1 to the home position position.

In the following description, when the members constituting the developing unit and the hopper are common to all the colors, the suffixes M, C, Y and Bk indicating the colors are omitted.

The toner supplied from the hopper 901 to the developing device 4 has the relationship shown in FIG. 10 between the remaining amount (g) of the toner in the hopper 901 and the supply amount (g / sec). That is, as shown by the dashed line, when the toner remaining amount sensor 902 detects that the toner has run out in the hopper 901 during normal copying, the toner is added to the hopper 901, and as shown by the solid line, The toner replenishment rate supplied from the hopper 901 in the initial stage of toner replenishment is significantly different from the case where toner is replenished to the empty hopper 901 at the time of initial installation of the apparatus. This is because, as described above, the toner becomes longer (hardens) when left unattended, and the replenishment rate becomes stable, whereas the hopper 9 remains empty when the apparatus is initially installed.
This is because, when the toner is replenished in 01, the toner is replenished in a state where the toner has not been accumulated by performing the copying operation in a state where the idle time is short, so that the replenishment rate is not stable.

In the case of the initial installation, after the toner is replenished for a while (in FIG. 10, when the remaining amount becomes about 250 g or less).
The toner replenishment rate is stable and almost the same as in the normal sequence).

In this embodiment, different supply parameters are provided for each mode, that is, a toner supply table, so that the toner supply amount in the initial installation mode and the toner supply amount in the normal copy sequence mode are the same. Thus, the variation of the toner supply amount is suppressed.

Next, the actual developer concentration control will be described with reference to the flowcharts of FIGS.

First, referring to FIG. 11, the ATR of M, C, Y
The control will be described.

As described above, M, C, Y in the present embodiment
As for (2), a control method of a composite system in which the optical ATR and the patch ATR are combined is adopted. In this control method, replenishment is performed by changing the target value of the optical ATR by detecting the patch in order to reduce the image density fluctuation due to the delay in the response of the optical ATR at the initial number of sheets during continuous copying.

As soon as copying is started, it is determined whether a patch is to be formed (S1101). Whether or not to form a patch is determined by incrementing a patch formation counter each time an image is formed, and by determining whether this counter has exceeded a predetermined value (20 times in this embodiment). When a patch is formed, the counter is cleared, the count is incremented each time an image is formed, and the same processing is repeated. Therefore, patches are formed at substantially predetermined intervals.

When forming a patch, the optical ATR sensor 5
The detection value is read by 0 (S1102), and thereafter, the optical ATR output fluctuation value (ΔV) given by the above-described equation (1).
Is calculated (S1103).

At this time, ΔV is given by ΔV = V _{target (n)} −V _ref-ini × (V _sig-now / V _ref-now ) (1 ′).

Note that V, which is the first term of the equation (1 '),
_{target (n)} is a recurrence formula given by: V _{target (n)} = V _{target (n-1)} + βΔV _pat (6) where ΔV _pat is an output fluctuation value at the patch output, and β is the patch This is a correction coefficient for performing feedback correction of the output fluctuation value (β = 0.4 is used in this embodiment).

Therefore, when a patch is formed for the first time after the apparatus is installed, V is the first term of the equation (1 ′).
_{target (n)} is V _{target (n)} = V _{target (0)} = V _sig-ini .

After the patch is formed, the target value of V _target (n) is obtained by feeding back the patch output fluctuation value ΔV _pat obtained by Expression (3) to Expression (6),
As a result, the optical ATR output fluctuation value ΔV can be calculated from the equation (1 ′).

Next, the amount of toner replenishment actually supplied from the hopper 901 to the developing device 4, ie, the toner replenishment time t, is calculated from the calculated optical ATR output fluctuation value ΔV (S11).
04). The calculation procedure is as follows.

First, a developer concentration fluctuation value ΔD (wt%) is calculated from the light ATR output fluctuation value ΔV as follows.

ΔD = ΔV / γ (7) γ is a value (= constant) indicating the correlation between the sig / ref AD output value and the voltage output value.

From the developer concentration fluctuation value ΔD obtained by this equation, the amount of toner to be supplied from the hopper 901 to the developing device 4 is determined via the toner supply table shown in FIG. 12A or 12B. .

The toner replenishment table shown in FIG. 12 is a table for obtaining a replenishment rate specified by the paper size from the calculated developer concentration fluctuation value ΔD. Based on the replenishment rate, the toner is replenished from the hopper 901 into the developing device 4 by connecting the toner replenishing clutch 903 for opening the toner replenishing port 909 for the image forming time t of the paper size for actually forming an image.

In the present embodiment, two types of the toner supply table are prepared, one in the normal sequence (FIG. 12A) and the one in the initial installation (FIG. 12B). Select and use the toner supply table.

As shown in FIG. 10, in the present embodiment, the amount of toner replenishment at the time of normal copying and at the time of initial installation is about 25% as indicated by the point a in FIG.
It becomes almost the same when it becomes 0 g or less. Therefore, the hopper 9
01, the toner remaining amount sensor 902 is set at a position where the toner remaining amount is about 250 g. When the toner remaining amount sensor 902 detects the absence of toner during the initial installation, the toner replenishment table is changed from the initial installation state to the normal state. Control is performed so as to switch to the current toner supply table.

When the toner replenishment table is used at the time of initial installation, the service mode used by the service person is set on the operation unit 704 (see FIG. 2) for setting the copy mode and the like mounted on the copying machine. In a mode for performing maintenance or the like referred to as "maintenance", an initial installation switch as a switching means is turned on. When the initial installation switch is on, the toner supply table is
(B) The toner supply table for initial installation is used.
When the toner remaining amount sensor 902 detects the level of 250 g, the initial installation switch is automatically turned off, and the toner supply table for the initial installation (FIG. 12)
(B)) from the toner supply table during normal copying (FIG. 1)
2 (a)).

Next, the toner supply clutch 903 is connected and toner is supplied from the hopper 901 to the developing device 4 for the toner supply time t calculated in step S1104 (S1).
105).

Next, the patch 5 formed on the photosensitive drum 1
8, the patch ATR sensor 60 reads the patch signal, and then calculates the patch output fluctuation value ΔV _pat given by the above equation (3) (S1107). The calculated ΔV _pat
From equation (6), the target value V of the optical ATR
_{The target (n)} is obtained (S1108). This V _{target (n)} is fed back and will be used in step S1103 when calculating the next optical ATR output fluctuation value ΔV.

On the other hand, when no patch is formed, light A
The detection value is read by the TR sensor 50 (S110
9) Then, the optical ATR given by the above equation (1 ′)
The output fluctuation value ΔV is calculated (S1110).

ΔV = V _{target (n)} −V _ref-ini × (V
_sig-now / V _ref-now ) (1 ')
_{The target (n)} is given by the above equation (6), and this value uses the target value calculated in step S1108 at the time of the previous patch formation.

Next, the toner replenishment amount to be actually supplied from the hopper 901 to the developing device 4, ie, the toner replenishment time t, is calculated from the optical ATR output fluctuation value ΔV calculated in step S1110 (S1111). The calculation procedure and the method of selecting the toner replenishment table are the same as those in step S1104 at the time of patch formation. The toner replenishment clutch t is connected to the toner replenishing clutch 903 to transfer toner from the hopper 901 to the developing device 4 for the determined toner replenishment time t. Supply (S1
112).

Finally, it is determined whether or not the copy has been completed (S1113). If the copy job is to be continued, the process returns to step S1101, and steps S1101 to S11 are performed.
13 is repeated, and when the copy job is completed, all the processes are completed and the copy is completed.

Next, the BK ATR control will be described with reference to the flowchart of FIG. In this embodiment,
For BK, a control method using only the patch ATR is adopted.

When copying is started, it is determined whether a patch is to be formed (S1201). Whether or not to form a patch is determined by incrementing a patch formation counter each time an image is formed, similarly to the control for M, C, and Y.
This counter has a predetermined value (1 in this embodiment).
Times). When a patch is formed, the counter is cleared, the count is incremented each time an image is formed, and the same processing is repeated. Therefore, patches are formed at substantially predetermined intervals.

When a patch is formed, a patch signal is read by the patch ATR sensor 60 from the patch 58 formed on the photosensitive drum 1 (S1202), and then the patch output fluctuation value ΔVpat given by the above equation (4) is obtained. Is calculated (S1203).

Next, the amount of toner replenishment actually supplied from the hopper 901 to the developing device 4, that is, the toner replenishment time t is calculated from the patch output fluctuation value ΔVpat (S12).
04). The calculation procedure is the same as that for M, C, and Y.
_{From the pat,} the developer concentration fluctuation value ΔD (wt
%), And from this ΔD, (a) or (b) in FIG.
The toner supply amount supplied from the hopper 901 to the developing device 4 is determined via the toner supply table shown in FIG.

In this case as well, the procedure for calculating the toner supply amount and the method for selecting the supply table are described in M and M.
This is the same as the processing in step S1104 in the case of C and Y.

Thereafter, the toner supply clutch 903 is connected for the determined toner supply time t to supply toner from the hopper 901 to the developing device 4 (S1205).

On the other hand, when a patch is not formed, toner is supplied using the previously calculated toner supply time t (S1206).

Thereafter, after the toner supply process is completed,
It is determined whether or not the copy is completed (S1207). If the copy job is to be continued, the process returns to step 1201, and the processes of steps S1201 to S1207 are repeated. Ends.

As described above, according to the present embodiment, the amount of toner replenishment that varies between the initial installation of the apparatus and the normal copying can be suppressed, and the developer concentration can be stabilized.

In this embodiment, the operation of calculating the various values, that is, the operation of calculation, is performed by the printer controller 701 including the operation means.

Embodiment 2 Next, a second embodiment of the present invention will be described.

In the relationship between the remaining amount of toner and the supply amount in FIG. 10 described in the first embodiment, even in the case of the normal copy sequence, as shown in FIG. I do. In this embodiment, when the remaining amount of toner exceeds 350 g indicated by a point b in the drawing, the supply amount increases. Thus, the present embodiment is characterized in that two types of toner supply tables used in the normal copy sequence are provided according to the remaining amount of toner, so that the amount of toner supply that varies depending on the remaining amount of toner is kept constant. .

Since the configuration and ATR control of this embodiment are almost the same as those of the first embodiment, only different portions will be described here.

In the normal sequence of the toner replenishment table used in steps S1104 and S1111 in the flowchart of FIG. 11 and step S1204 in FIG. 13, two kinds are prepared with a remaining toner amount of 350 g as a boundary. Then, the toner remaining amount sensor 902 is set at the position of 350 g of the remaining toner amount of the hopper, and the output of the toner remaining amount sensor 902 is used to select a toner replenishing table to be used and determine the toner replenishing amount.

As described above, according to the present embodiment, in the case of a normal copy sequence, the amount of toner replenishment that varies depending on the amount of remaining toner can be more reliably kept constant.

Embodiment 3 Next, a third embodiment of the present invention will be described.

In the present embodiment, a total of three types of tables are provided: a toner replenishment table at the time of initial installation, and a toner replenishment table when the remaining amount of toner during the normal copy sequence is small and large. Based on the initial installation switch (hereinafter referred to as “initial installation SW”) and the signals of the two remaining toner levels which detect the remaining toner levels, it is possible to select the optimum toner replenishment table and stabilize the toner replenishment amount. Features.

The toner replenishment table is a toner replenishment table α at the time of initial installation, a replenishment table γ other than at the time of initial installation, that is, a replenishment table γ when the amount of remaining toner is large in a normal copy sequence.
Three types of replenishment tables β are used when the remaining amount of toner is small during normal copying.

Steps S1104 and S1111 in the flowchart of FIG. 11 and step S12 in FIG.
Processing for selecting a toner supply table to be used in step 04 will be described with reference to the flowcharts in FIGS. 14 and 15.

Since the configuration and ATR control of this embodiment are almost the same as those of the first embodiment, only different portions will be described here.

First, it is determined whether or not the initial installation switch is on (S1501). The initial setting SW can be input from the operation unit 704 as described above. If the initial installation SW is on, the toner supply table α is used (S15).
02). If the initial installation SW is off, it is determined whether the remaining toner level v satisfies v ≧ b (S150).
3). If v ≧ b, the toner replenishment table γ is used (S1505). Otherwise, that is, if v <b, the toner replenishment table β is selected and used (S1504).

As described above, the initial setting SW is controlled so that when the remaining toner level v detects v ≦ a, the initial setting SW is automatically switched off.

As described above, there are a total of three types of tables, a toner replenishment table at the time of initial installation and a toner replenishment table when the remaining amount of toner during normal copying is small and large. By selecting and using an optimal toner supply table in accordance with the remaining amount of toner, the amount of toner supplied from the hopper to the developing device can be stabilized.

The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copier, a facsimile). Device).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the above-described embodiment to a system or an apparatus, and a computer (or CPU or MPU) of the system or apparatus to supply the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

Examples of the storage medium for supplying the program code include a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, and a CD-RO.
M, CD-R, magnetic tape, nonvolatile memory card,
A ROM or the like can be used.

Further, not only the above-described embodiment is realized by executing the program code read by the computer, but also an OS (operation system) running on the computer based on the instruction of the program code. However, it goes without saying that a case where some or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

Further, the program code read from the storage medium is used by a function expansion board inserted into the computer, a function expansion board connected to the computer, or a CPU provided in a function expansion unit to execute a part or all of the actual processing. Of course, and the processing realizes the function of the above-described embodiment.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

[0126]

As described above, according to the image forming apparatus of the present invention, the toner density detecting means for detecting the toner density in the developing means and the toner remaining quantity detecting means for detecting the remaining toner in the hopper means. Means, a first supply parameter and a first supply parameter for calculating a density variation value of the developer from the density data detected by the toner density detection means, and determining a toner supply amount to be supplied from the hopper means to the development means. Computing means for determining a toner supply amount through two supply parameters; and switching means for switching use of the first supply parameter and the second supply parameter,
When the switching means for selecting the parameter is set, the first supply parameter is used, and when the remaining toner amount in the hopper means detected by the remaining toner detecting means reaches a predetermined level. By canceling the setting of the switching means and controlling the second supply parameter to be used, the toner for replenishing the toner from the hopper means to the developing means irrespective of the initial installation and the normal sequence. The developer concentration can be stabilized by suppressing the variation in the replenishment amount, and a high-quality image can be obtained.

Further, according to the image forming apparatus of the present invention, a toner density detecting means for detecting the toner density in the developing means,
A toner remaining amount detecting unit for detecting a remaining amount of toner in the hopper unit, a toner density variation value calculated from the density data detected by the toner density detecting unit, and a toner supplied from the hopper unit to the developing unit. Calculating means for determining the toner supply amount through a first supply parameter and a second supply parameter for determining the supply amount,
The toner remaining amount detection unit uses the first supply parameter until the remaining toner amount detects that the supply level has reached the switching level of the supply parameter. By using the second replenishment parameter, regardless of the initial installation and the normal sequence, a variation in the amount of toner replenishment when replenishing toner from the hopper means to the developing means is suppressed and the developer concentration is stabilized. And high quality images can be obtained.

Further, according to the image forming apparatus of the present invention, the toner density detecting means for detecting the toner density in the developing means, the toner remaining quantity detecting means for detecting the remaining toner quantity in the hopper means, A first, second, and a third method for calculating a density variation value of the developer from the density data detected by the detection means and the initial density data, and determining a toner supply amount supplied from the hopper means to the development means. Third
Computing means for determining the toner supply amount through the replenishment parameters, and switching means for switching the use of the first, second, and third replenishment parameters. When the switching means is set, In a state where the switching means is set using the first supply parameter, the remaining amount of toner in the hopper means detected by the remaining toner amount detecting means reaches the first remaining level. The setting of the switching means is released, the setting of the switching means is released using the third supply parameter, and the hopper detected by the toner remaining amount detecting means is used. When the remaining amount of toner in the printer reaches the second remaining level, control is performed so as to use the second replenishment parameter. Therefore, it is possible to achieve a stable developer concentration by suppressing a variation in the amount of toner supplied when the toner is supplied from the hopper unit to the developing unit, and further reduce the variation in the amount of toner supplied during a normal sequence. Thus, it is possible to stabilize the developer concentration while suppressing the occurrence of a high-quality image.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a color image forming apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a control system in the color image forming apparatus of FIG.

FIG. 3 is a schematic sectional view showing one embodiment of a developing device.

FIG. 4 is an explanatory diagram schematically showing an embodiment of a patch ATR sensor.

FIG. 5 is an explanatory view schematically showing a structure of an optical ATR sensor.

FIG. 6 is a diagram for explaining the principle of the ATR according to the present invention.

FIG. 7 is a schematic front view showing a hopper in the color image forming apparatus of FIG. 1;

FIG. 8 is a view for explaining the structure of the hopper of FIG. 7;

FIG. 9 is a cross-sectional view illustrating a positional relationship between a hopper and a developing device.

FIG. 10 is a diagram showing a correlation between a remaining toner amount and a replenishment amount at the time of initial installation and at the time of normal copying.

FIG. 11 is a flowchart illustrating toner supply control of M, C, and Y developing units.

FIG. 12 is a diagram illustrating a toner supply table.

FIG. 13 is a flowchart illustrating toner supply control of the BK developing device.

FIG. 14 is a diagram showing a correlation between a remaining toner amount and a replenishing amount at the time of initial installation and at the time of normal copying in another embodiment of the present invention.

FIG. 15 is a flowchart illustrating control for selecting an optimal toner supply table according to another embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 photosensitive drum (image carrier) 4y, 4c, 4m, 4Bk developing unit (developing unit) 50 optical ATR sensor (toner density detecting unit) 60 patch ATR sensor (toner density detecting unit) 701 printer controller (calculating unit) 704 operation Unit 901 Hopper (hopper means) 902 Toner remaining amount sensor (toner remaining amount detecting means)

Claims (7)

[Claims] 1. An image comprising: an image carrier on which a latent image is formed; developing means for containing a developer containing toner and developing the latent image with toner; and hopper means for supplying toner to the developing means. In the forming apparatus, a toner concentration detecting means for detecting a toner concentration in the developing means, a toner remaining amount detecting means for detecting a remaining amount of toner in the hopper means, and the density data detected by the toner concentration detecting means. Calculating means for calculating a developer density variation value and determining a toner supply amount through a first supply parameter and a second supply parameter for determining a toner supply amount to be supplied from the hopper means to the developing means; Switching means for switching between use of the first supply parameter and the second supply parameter, and a switching means for selecting the supply parameter. Is set, the first supply parameter is used, and when the remaining amount of toner in the hopper unit detected by the remaining toner amount detecting unit reaches a predetermined level, the setting of the switching unit is performed. Wherein the image forming apparatus is controlled to use the second supply parameter. 2. The image forming apparatus according to claim 1, wherein the first supply parameter is used when the image forming apparatus is initially installed, and the second supply parameter is used during a normal sequence. 3. The image forming apparatus according to claim 1, further comprising an operation unit, wherein the setting of the switching unit can be set via the operation unit. 4. An image comprising: an image carrier on which a latent image is formed; developing means for containing a developer containing toner and developing the latent image with toner; and hopper means for supplying toner to the developing means. In the forming apparatus, a toner concentration detecting means for detecting a toner concentration in the developing means, a toner remaining amount detecting means for detecting a remaining amount of toner in the hopper means, and the density data detected by the toner concentration detecting means. Calculating means for calculating a developer density variation value and determining a toner supply amount through a first supply parameter and a second supply parameter for determining a toner supply amount to be supplied from the hopper means to the developing means; The first replenishment parameter until the toner remaining amount detecting means detects that the toner remaining amount has reached the replenishment parameter switching level. Using the data, after it is detected that reaches the switching level image forming apparatus characterized by using said second supply parameters. 5. An image comprising: an image carrier on which a latent image is formed; developing means for containing a developer containing toner and developing the latent image with toner; and hopper means for supplying toner to the developing means. In the forming apparatus, a toner density detecting means for detecting a toner density in the developing means, a toner remaining quantity detecting means for detecting a remaining toner quantity in the hopper means, a density data detected by the toner density detecting means and an initial value. And a toner supply amount through first, second, and third supply parameters for determining a supply amount of toner supplied from the hopper unit to the development unit. And a switching means for switching the use of the first, second, and third supply parameters, and a switching means for selecting the supply parameters. Is set, the first supply parameter is used, the switching means is set, and the remaining amount of toner in the hopper means detected by the remaining toner amount detecting means is used. When the first remaining amount level is reached, the setting of the switching means is released, the third supply parameter is used, and the setting of the switching means is released. An image forming apparatus configured to control to use the second supply parameter when the remaining amount of toner in the hopper detected by the means reaches a second remaining amount level. 6. The first replenishment parameter is used when the image forming apparatus is initially installed, and the second replenishment parameter is lower than a second remaining level at which the remaining amount of toner in the hopper means is small during a normal sequence. 6. The image forming apparatus according to claim 5, wherein the third supply parameter is used when the remaining amount of toner in the hopper means is equal to or higher than a second remaining amount level in a normal sequence. 7. The image forming apparatus according to claim 6, further comprising an operation unit, wherein the setting of the switching unit can be set via the operation unit.