JPS6232477A - Method for controlling supply quantity of developer - Google Patents

Abstract

PURPOSE:To use a reference reflecting plate and a light quantity sensor to control the supply quantity of a developer by using the reference reflecting plate and the light quantity sensor to detect the image density of an original and forecasting developer consumption in accordance with the image density to supply the quantity of developer corresponding to this developer consumption. CONSTITUTION:A reference reflecting plate 3 is provided and a light quantity sensor 11 is arranged just behind a lens 9, and a reference quantity of light is obtained in accordance with the quantity of reflected light from the reference reflecting plate 3 and is compared with the quantity of reflected light from an original surface to detect the image density of an original 2, and the quantity of the developer corresponding to the image density is supplied into a developing machine 15, thus controlling the supply quantity of the developer. That is, the developer consumption is forecasted in accordance with the image density of the original 2, and the quantity of the developer corresponding to this consumption is supplied. The operation of a developer supply device motor 16 is controlled by a power source 14 to supply the developer to the developing machine. Outputs of said reference reflecting plate 3 and the light quantity sensor 11 which detects the quantity of reflected light from the original surface are given as data to a CPU 13 through an A/D converter 12 of a control system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the amount of developer supplied when the developer is supplied to a developing machine in an image forming apparatus using a developer.

[Conventional technology]

Conventionally, when controlling the supply of developer in an electrostatic copying machine that uses developer, the following method has been adopted. That is, there are methods of detecting the toner concentration using a detection method using magnetic permeability, for example, and keeping the toner concentration within a certain range;
Solid (Sol) is applied on the photoreceptor or conductive glass surface.
id) A method of developing an image, detecting its density, and controlling the amount of toner supply to keep the solid density constant.

However, in the former method based on toner concentration detection, such as the magnetic permeability detection type, the bulk specific gravity changes depending on conditions even if the toner concentration is the same, making it difficult to apply to developers whose magnetic permeability changes. Furthermore, for developers whose optimal toner density changes depending on the environment, especially humidity, it is necessary to make settings according to the environment, and the latter method of detecting the density of a solid image is subject to errors due to dirt, etc. Not only do each method have its own problems, such as problems with the reliability of the concentration sensor due to the This poses an obstacle to introducing such a method.

[Problem that the invention seeks to solve]

The present invention is intended to solve the problem of cost, speed, etc., in addition to the problems such as the limitations on the developer used and the reliability.

[Means for solving problems]

For this reason, the present invention uses a reference reflector and a light intensity sensor to detect the entire image density of the original, predicts the total amount of developer consumption from the image density, and supplies an amount of developer corresponding to that amount. This control is performed using a total reference reflector and a light amount sensor.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In Figure 1, (1) is the platen glass of the static copying machine, (2) is the original, (3) is the reference reflector plate provided at one end of the platen glass (1), and the exposure lamp (4) is the reference. It is moved along the lower surface of the reflecting plate (3) and the platen glass (1). (5) to (8) are mirrors, and (9) is a lens. These components constitute the optical system, and the exposure lamp (
The reflected light obtained during the irradiation in step 4) is made incident on this optical system, and when the original (2) is copied, an original image is formed as an electrostatic latent image on the surface of the photoreceptor (9). A light amount sensor aD is provided immediately behind the lens (9) in the middle of the optical system.

This light intensity setting (11) is used to control the original (2) as described later.
This is used to read the amount of light reflected from the reference reflector (3) and the amount of light reflected from the document surface when detecting the image density of the reference reflector (3). 1) Place it in a position that does not interfere with the image formation above.

This makes it possible to read the reflected light Nk over a wide range of areas, including no single point, during control.

(12+ is the A/D converter, αJ is the central processing unit (CPU) of the microcomputer, (14) is the CPU
The developer is supplied to the developing machine (15) by the motor controlled by f131 and the power supply for driving. (3) The output of the light amount sensor (11) that detects the amount of reflected light on the document surface is given as data to the CPUQ31-\ via the A/D converter (121k) of the control system.

Note that since the developer supply amount is controlled by detecting the entire image density of the document (2), unlike the conventional method described above, a reference reflector plate (as shown in FIG. 1) is used as hardware. 3) A light amount sensor (11) is used, but the reference reflector (3) can also serve as a reflector for the AE function and the light amount automatic correction function. That is, the reference reflector f3) id,
When the present control method is applied to a copying machine having an AE function or the like, it may be a copying machine that is used for the AE function or the like. This point also applies to the light amount sensor (ill).

The developer supply amount is controlled by using the reference reflector plate (3) as described above.
), and a light amount sensor G11t is placed immediately behind the lens (9), and the reference light amount is obtained from the amount of light reflected by the reference reflector (3), and relative comparison is made with the amount of reflected light from the document surface.
This is done by detecting the image density of the document (2) and supplying an amount of developer corresponding to the image density into the developing machine (15). , and supply the corresponding amount of developer.

The image density can be detected by reading and relatively comparing the amount of light reflected from the reference reflector (3) and the total amount of light reflected from the document surface, and the image density of the document (2) at this time. Image density = 1 - (original reflected light amount/reference light amount)...(1)
However, in this example, as a simple method, the standard light amount, - x reference light amount, n x reference light amount,...
A method was adopted in which a series of standard values such as . . . , . Regarding control not based on this ranking,
This will be explained in the next example.

Now, as mentioned above, if you want to derive a series of reference values (reference light intensity minus 1 x reference light intensity) from the reference light intensity, compare them with the original surface reflected light JjL/'t'', and rank them. , read the amount of reflected light from the reference reflecting plate (3).Then, from the amount of light at this time, the reference amount of light when the image density is -0 is obtained.

Next, as mentioned above, the standard light amount, 22 x standard light amount, □
×Reference light amount, −−×Reference light amount,...
Since a series of reference values such as n is provided, the reflected light amount values are read at regular intervals during document scanning, that is, during copying or blank scanning, and are ranked by comparing with the above reference values.

Table 1 below provides an example of this.

Table 1 In the above table, the numbers in parentheses are for adjustment.

Then, the rank value is integrated by the number of times of sampling, and the required toner amount is calculated and controlled based on this integrated value.

In this way, a reference reflector (3λ) is provided, a light amount sensor αD is placed on the blade immediately after the lens (9), and the original (
By detecting the image density (2), the amount of developer consumed can be predicted, and the supply of developer can be controlled by supplying an amount of developer corresponding to the amount of developer consumed.

Therefore, the only required hardware is the reference reflector (3) and the light amount sensor 01). Furthermore, since these functions can be used in common with the AE function, etc., if applied to control the developer supply of a copying machine that already has such a function, further cost and space savings can be realized.

In addition, as mentioned above, if a series of reference values are derived from the reference light intensity, and the total amount of light reflected from the document surface is compared with the reference values to rank them, it is possible to make the method simpler and to make the ranking even easier. By preparing several types of values to be used as shown in Table 1, it becomes possible to easily carry out all adjustments.

Next, other embodiments of the present invention will be described.

In the embodiment described above, when the amount of developer consumed is predicted from the image density of the document (2) and the corresponding amount of developer is supplied, a method is adopted in which the rank values are integrated as described above.
In this embodiment, in order to detect the image density, the reference light amount is obtained by reading the reflected light amount of the reference reflector plate (3) using the total light amount sensor 01), and the amount of reflected light from the document surface is read by the light amount sensor Uυ.
Then, calculate the image density = 1 - (amount of reflected light from the original/reference light amount), and then multiply the integrated value obtained by the image area width by a coefficient to find the required amount of developer. Make it.

That is, first, the amount of light reflected by the reference reflector (3) is read. A reference light amount when image density=0 is obtained from the light amount at this time. This may be done by adjusting the reference reflector (3) so that the read value can be used as is, or it may be determined by calculation.

Next, the amount of reflected light is read at regular intervals while scanning the document (during copying or blank scanning).

Then, A=1-(amount of original reflected light/reference light amount) is calculated and integrated by the number of times of Ai sampling.

Here, the number of sampling times is the number of sampling times=sampling period/scan length (=image area length).

Next, the required amount of developer is determined from the integrated value of A using the following formula.

Required developer amount = A integrated value x image area width Xk (coefficient)・
(2) Then, the developer supply device is controlled according to this required amount of developer, and the developer is supplied.

The developer is supplied as follows. That is, it is performed in the next cycle after reading the image density.

Figures 2 and 3 show examples of this; the former is 1
In the case of one copy operation, the latter is a timing chart of the print switch, document scan, developer drive motor, and developer supply device motor (161) in the case of continuous copy operation. As shown, the developer supply device is driven for a period of A2 during the next copy cycle 12 based on the image density read during the copy cycle T, and the image density read during the copy cycle T2 is based on this fL. During the next copy cycle T3, the developer supply device is driven for a period A3.During continuous copying, the image density is read only in the first cycle as shown in FIG.
From the second cycle onwards, the developer is supplied based on the second cycle.

In this way, the developer is supplied in such a manner that during the next copying operation, the developer is supplied in tones corresponding to the previously increased image density.

Further, in this case, if the supply cannot be completed in one copy cycle, the surplus may be stored in the memory and used from the next cycle onward. In other words, if the supply cannot be completed, it will be reflected in the next cycle and thereafter. Furthermore, it is also possible to integrate the supply time until it exceeds a certain value and then operate the system at the point when the supply time exceeds a certain value. That is, in consideration of the responsiveness of the developer supply device motor (16), the integration may be performed until a certain period of time or more is reached, and the operation may be performed every several copies.

Regarding the developer supply operation as described above,
The embodiments described above may also be similar.

Next, still another embodiment of the present invention will be described.

In this embodiment, the image density is detected by relatively comparing the amount of light reflected from the reference reflector (3) and the amount of light reflected from the document surface by the total light amount sensor (1υ), k (coefficient) x image density x image area area. The amount of consumed developer, that is, the required developer 'ji, given by is determined, and the amount of developer supplied is controlled in stages, and furthermore, it is linked with the copy density selection function.

That is, the steps from reading the amount of reflected light from the reference reflector (3) to determining the required amount of developer as described above are the same as in the previous embodiment, but then the developer supply device motor (161) is calculated from the required amount of developer. Try to determine the operating time.Also,
In this case, the rotation speed of the developer supply device motor (161) may be fully controlled.

The following Table 2 shows this example, when the capacity of the developer supply device is 180 mg/see and the required developer ff1 (B
4) when the original image density (per 1%) is 11 mg Lv.

Table 2 Required developer amount MD ■ 0≦Mo<45 ■ 45≦MD<90 ■ 90≦MD <150 ■ 150≦Mo <220 ■ 220≦MD Note that in Table 2 above, D is the standard value. However, the standard value can be changed depending on the situation.

Further, the operation time is changed depending on the selection status of the copy/degree selection function. In other words, for example, "Usu<"
1. For copying machines that allow you to select a copy density such as ``Light'' or ``Normal,'' this function should be linked to the copy density selection function.For example, when D is a standard value. If we take , we can make them correspond as follows: B ← "tingle" C ← "ya\light" D ← "normal" E ← "ya 5 thick" F ← "kogu".

In this way, as a mode of controlling the amount of developer supplied,
Once the required amount of developer is determined, it is possible to determine the range within which it falls and control the amount of developer supplied step by step.Furthermore, the system may be linked with a copy density selection function. You can.

Next, still another embodiment of the present invention will be described.

In this embodiment, the image density is detected using the reference reflector (3).
By relatively comparing the amount of reflected light from the original surface with the reflected light from the document surface@total light amount sensor Uυ, step 9 sets an upper limit to the image density read at this time.

Naturally, the originals to be copied by a copying machine may have different background colors, such as a blank original or a colored original.

When handling such originals, the control of the amount of developer supplied is carried out using the reference reflector (3) and the light sensor (3), as described above.
11) has advantages over conventional methods in terms of cost, space, etc., and can be easily introduced even with low-cost machines, but on the other hand, it has the following disadvantages: There is a risk that this may occur. In other words, an original with a colored background has less reflected light than an original with a white background, and even if the image density is the same, the detected image density will be higher in the case of a colored original. In the case of this control method of supplying a certain amount of developer, there are cases where proper control is hindered by this. In particular, when combined with an automatic exposure function, etc., there is a large difference between the consumption amount and the supply amount.

As mentioned above, setting an upper limit on the image density to be read is because
This is to prevent excessive supply of developer in the case of such colored originals.

A specific example in which the image density is set to 25 inches as the upper limit will be described below.

First, [111 each F': 2! ;
Read reflected light i[1 of ffi reflection (3). To obtain the reference light amount when the image density is 20 from the light 1t when the image density is 2S; The same is true for the point that 5 may be used as is, or may be determined by calculation.

Next, while scanning the document (during copying or blank scanning), read the reflected light amount value at regular intervals, and
= 1 - (amount of reflected light on the original, /reference light amount) is calculated completely, and this A
The integration is performed for the n number of sampling cycles expressed by the ratio of the i sampling period to the scan length (=image area length). Here, if the value of A is A > 0.25, this is calculated as A = 0.25. 25. As a result, even if a relatively large number of colored originals are used, the above-mentioned inconveniences will not occur, and the advantages of this control method will not be lost (such as when the image density is 25 cm). Although it is rare that a document exceeding the maximum capacity is copied, if it does occur, it is possible to prevent an excessive supply of developer as described above).

Next, if A is integrated with the upper limit suppressed in this way, the A integration value x image area width x1c (
Calculate the required amount of developer from the coefficient).

Then, the entire developer supplying device is controlled according to the required amount of developer to supply the developer.

In the above example, an upper limit is set on the image density to be read, but the same effect can be obtained by setting an upper limit on the developer supply amount. Therefore, if it is desired to prevent the possibility of excessive supply of developer in the case of a colored original, it is sufficient to set an upper limit on the image density reading or the amount of developer supplied.

Also, if you use a method that corrects the read image density by receiving information from the AE function (original background density detection function), it will be possible to more accurately handle colored originals, and there will be no need to set an upper limit like in the previous method. It disappears.

In the case of each of the above embodiments, the configuration is the same as the hardware configuration shown in FIG. 1, only the control program of the microcomputer is different. The sensor 01) is the same in that it can control the developer supply amount by using the sensor 01) all around the sensor, and it is also possible to control the amount of developer supplied by using the sensor 01). The same goes for the fact that there is no problem with accepting the offer. Furthermore, the specific control modes described for each of the above embodiments do not preclude implementing one or more of them in combination as necessary; for example, in the case of the ranking method described first. In this case, when the required amount of developer is calculated and supplied based on the integrated value obtained by integrating the rank values, an upper limit may be set on the amount of developer supplied, or the like may be combined as appropriate.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to control the developer supply amount by supplying the developer in an amount corresponding to the image density of the original. All controls can be carried out using the installed light quantity sensor, and these can also be used for the AE function, etc., so if the structure is shared, it has the advantage of further reducing costs and saving space.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the hardware configuration of each embodiment method of the present invention, FIG. 2 is a timing chart for explaining developer supply for one copy operation, and FIG. 3 is a continuous copy operation diagram. It is a timing chart which shows an example. [Code explanation]

Claims (1)

[Claims] A reference reflector is provided, and a light amount sensor is placed in the optical system to detect the amount of light reflected from the reference reflector and the amount of light reflected from the surface of the document, and the amount of developer consumed is predicted by detecting the image density of the document. A developer supply amount control method characterized by supplying a corresponding amount of developer.