JP2000010394A - Toner quantity detecting device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and precisely detect the toner quantity even if toner scattering causes the contamination of a light emitting element and the contamination of the light receiving element window and light emitting side window of a toner cartridge by performing the toner quantity detection at prescribed intervals on and after on the basis of the detected toner quantity. SOLUTION: This toner quantity detecting device performs the toner quantity in a toner cartridge. Emission of a light emitting element is performed just after replacement by a new toner cartridge, and the number of pieces to print up to the following measurement of toner quantity is set according to the toner quantity measured on the basis of the emission signal of a light receiving element. Namely, when the toner residual quantity is detected, the interval to the following toner quantity detection is extended when the toner quantity (toner residual quantity) is 100% in the first measurement. For example, the following detection of toner quantity A2 is performed after printing of several hundreds pieces from the first detection of toner quantity A1, and the interval to the following toner quantity detection is shortened on and after to increase the frequency of toner quantity detection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner amount detecting device for detecting the remaining amount of toner and detecting the integrated amount of waste toner in an image forming apparatus such as a copying machine, a printer, a facsimile or the like using an electrophotographic system.

[0002]

2. Description of the Related Art The amount of residual toner used in a developing process of an image forming apparatus using an electrophotographic system or the integrated amount of waste toner after the developing process is detected by a light transmission type toner amount detecting device.

As shown in FIGS. 9 and 10, a conventional light-transmitting toner amount detecting device for detecting the integrated amount of waste toner is a light receiving side window 103 of a toner cartridge 101 from which toner (waste toner) is collected. The light receiving element 102 and the light emitting element 105 are disposed to face each other outside the light emitting side window 104. In the toner cartridge 101, a fin 108 for rotating the toner around the central axis to carry the toner into the toner cartridge 101, a stirring rod 106 for stirring the toner by rotation, and a stirring rod 106
A wiper 107 for wiping the light receiving side window 103 and the light emitting side window 104 by 106 rotations, a sleeve 109 for collecting toner, and a rotating sleeve 118 are provided.

In FIG. 10, reference numeral 110 denotes a detection window (light-receiving window, light-emitting window), 112 denotes a bearing for fixing the fin 108, and 114 denotes a driving unit (not shown) for rotating the stirring rod 106. Reference numeral 115 denotes a mechanical input unit for detachably attaching the toner cartridge 101 to an apparatus main body (not shown), and 116 denotes a boss for positioning the toner cartridge 101 with respect to the apparatus main body (not shown).

When the toner cartridge 101 is inserted into the apparatus main body (not shown), the positioning is performed by the boss 116 which is a positioning portion, and the toner cartridge 101 is mechanically connected. The apparatus body (not shown) collects toner (waste toner)
When the gear 114 is rotationally driven by driving of a driving unit (not shown), the fin 108 is rotated, and the sleeve 109 and the stirring rod 106 are rotated.

In the conventional toner amount detecting device described above, the toner (waste toner) collected from the photosensitive drum (not shown) by the rotation of the sleeve 109 is carried into the toner cartridge 101 by the adjacent rotating sleeve 118. Then, the fins 108 further carry the cartridge 101 inside.

When a large amount of used and collected toner accumulates, the toner starts to be agitated by the stirring rod 106 at a constant period, and the light transmitted through the light receiving window 103 and the light emitting window 104 starts to be blocked by the toner. . And stirring rod 1
06 by the wiper 107 attached to the light-receiving side window 1
03 and the light emitting side window 104 are wiped, and until the wiped space is filled with toner, the light receiving side window 103 is wiped.
After the light-emitting side window 104 is wiped, the light transmitted from the light-emitting element 105 to the light-receiving element 102 continues to pass, and this time starts to decrease as the toner amount increases.

In the sequence for detecting the toner amount based on the light receiving signal from the light receiving element 102, the stirring rod 1
While the light emitting element 06 rotates several times, the light emitting element 105 is turned on, the output voltage (light receiving signal) of the light receiving element 102 is detected, and a comparison is made with a preset threshold value. The time is counted as the time during which light is transmitted. By this count number, for example, when the count number is small,
It is determined that the accumulated amount of toner (waste toner) in the toner cartridge 101 is in an increased state.

On the other hand, when the remaining amount of toner in the toner cartridge is detected, the amount of toner decreases with time. Therefore, the light transmission time increases and the number of counts increases. judge.

[0010]

By the way, in the above-mentioned conventional toner amount detecting device, the light emitting element 105 and the light receiving element 1 due to the influence of toner scattering during the image forming process.
02 and the light receiving side window 10 of the cartridge body 101.
3 and the light emitting side window 104, toner
The light emission amount decreases due to the element lifetime of 05,
There has been a problem that the detection accuracy is lowered and the toner amount cannot be accurately detected.

Accordingly, the present invention is to stably and accurately detect the toner amount even when the light emitting element and the light receiving element are stained due to toner scattering or the like and the light receiving side window and the light emitting side window of the toner cartridge are stained. It is an object of the present invention to provide a toner amount detecting device of an image forming apparatus which can perform the above.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a toner amount detecting device for optically detecting the amount of toner used in an electrophotographic image forming apparatus. A light-emitting element that enters light into a portion of the container that allows light to pass therethrough, a light-receiving element that receives light transmitted through the container, and a toner amount in the container based on a light-receiving signal output from the light-receiving element. Control means for detecting the amount of toner, the control means performing subsequent toner amount detection at predetermined intervals based on the detected toner amount.

Further, the detection means is characterized in that as the toner amount approaches the detection limit value, the interval between the detection of the next toner amount is shortened.

Further, the detecting means changes the light emission timing of the light emitting element in accordance with the number of images formed by the image forming apparatus.

Further, in a toner amount detecting device for optically detecting a toner amount used in an image forming apparatus using an electrophotographic system, a light emitting element for irradiating light to a light transmitting portion of a container for storing toner is provided. And a light receiving element that receives light transmitted through the inside of the container, and control means for controlling light emission of the light emitting element, wherein the control means has a pulse width of a light receiving signal output from the light receiving element. Comparing the pulse width of a preset reference value with the calculated pulse width and calculating the difference, and controlling the light emission amount of the light emitting element so that the light receiving signal of the light receiving element is constant based on the calculation result. I have.

Further, in a toner amount detecting device for optically detecting a toner amount used in an image forming apparatus using an electrophotographic system, a light emitting element for emitting light to a light transmitting portion of a container for storing toner is provided. And a light receiving element that receives light transmitted through the inside of the container, and control means for controlling light emission of the light emitting element, wherein the control means adjusts the light emission timing of the light emitting element, It is characterized in that the light emitted from the light emitting element is synchronized with a stirring cycle of a stirring member for stirring toner in an optical path incident on the light receiving element or a cycle of wiping a window provided on a light transmitting surface of the container.

(Operation) According to the present invention, the subsequent toner amount detection is performed at predetermined intervals based on the detected toner amount, so that as the toner amount approaches the limit value, the interval until the next toner amount detection is increased. By shortening the frequency and increasing the frequency of toner amount detection, accurate measurement near the limit value of the toner amount can be performed.

Further, the pulse width of the light receiving signal output from the light receiving element is compared with the pulse width of a preset reference value to calculate the difference, and the light receiving signal of the light receiving element is made constant based on the calculation result. By controlling the light emission amount of the light emitting element so that the toner amount can always be accurately detected.

Further, the light emission timing of the light emitting element is set at a stirring cycle of a stirring member for stirring toner in an optical path where light emitted from the light emitting element in the container enters the light receiving element, or provided on a light transmitting surface of the container. By synchronizing with the window wiping cycle, a decrease in the amount of light received by the light receiving element can be prevented, and the toner amount can be detected at an accurate detection timing.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1> FIG. 1 is a schematic diagram showing an image forming apparatus (a full-color mode laser beam printer in the figure) using an electrophotographic process system, and FIG. FIG. 2 is a configuration diagram illustrating a light transmission type toner amount detection device that detects a remaining toner amount (or an integrated amount of waste toner).

In this image forming apparatus, a drum type electrophotographic photosensitive member (hereinafter, referred to as a “printer engine”) is installed in an apparatus body (printer engine) 19.
A photosensitive drum 1), a charging roller 2, an exposure device (scanner device) 3, a developing device 4, an intermediate transfer belt 5 as an intermediate transfer member, a secondary transfer roller 7, a transport guide member 8, a fixing device 9, and the like. I have.

The photosensitive drum 1 has an organic photoconductor layer (not shown) on a drum base (not shown) made of aluminum. A drive motor (not shown) is connected to the photosensitive drum 1, and the photosensitive drum 1 is rotated at a predetermined process speed by the drive motor.

The charging roller 2 is pressed against the surface of the photosensitive drum 1 with a predetermined pressing force, rotates following the rotation of the photosensitive drum 1, and receives a predetermined charge from a power source (not shown). The photosensitive drum 1 is charged to a predetermined polarity and potential by applying a bias.

The exposure device (scanner device) 3 includes a laser diode (not shown), a polygon mirror, an imaging lens system,
And a reflection mirror 3a. When an image signal is input, the laser diode irradiates the polygon mirror with image light corresponding to the image signal. The image light reflected by the high-speed rotating polygon mirror is used to form an image forming lens system and a reflection mirror 3.
By selectively exposing the surface of the photosensitive drum 1 rotating at a constant speed via a, an electrostatic latent image is formed on the surface of the photosensitive drum 1.

The developing device 4 includes a yellow developing device 4Y and a magenta developing device 4 for visualizing the electrostatic latent image.
M, a cyan developing unit 4C, and a black developing unit 4Bk. The yellow developing unit 4Y, the magenta developing unit 4M, the cyan developing unit 4C, and the black developing unit 4Bk have a sleeve 4Ys, a sleeve 4Ms, a sleeve 4Cs, and a sleeve 4Bks, respectively. Is provided.

Yellow developing unit 4Y, magenta developing unit 4
The M, cyan developing unit 4C, and black developing unit 4Bk rotate with the rotation of the developing rotary 4A during image formation, and a predetermined sleeve 4Ys, a sleeve 4Ms, a sleeve 4Cs, and a sleeve 4Bks move 30 times with respect to the photosensitive drum 1.
They face each other with a small interval of about 0 μm. This allows
The predetermined yellow developing unit 4Y, magenta developing unit 4M, cyan developing unit 4C, and black developing unit 4Bk are stopped at the developing position facing the photosensitive drum 1, and a visible image is formed on the photosensitive drum 1.

The intermediate transfer belt 5 includes driving rollers 5a, 2
It is supported by the next transfer opposing roller 5b and the tension roller 5c so that an appropriate tension is maintained. A primary transfer roller 6 is disposed in contact with the photosensitive drum 1 via an intermediate transfer belt 5.

Next, an image forming operation of the above-described image forming apparatus will be described.

At the time of image formation, a print request signal is input from a not-shown external host computer to the printer engine controller. Next, in response to the print signal, the inside of the apparatus main body 19 starts a scanner motor (not shown) and then performs a print start preparation operation. When the apparatus enters a standby state, the print operation is started.

The transfer material P such as paper is supplied to the cassette paper feeding unit 1.
The paper is fed from either the cassette feeding roller 11 from 0 or the multi-manual feeding roller 13 from the multi-manual feeding unit 12, and is conveyed by the conveying rollers 14. Then, the transfer material P temporarily stops after the skew is corrected by the registration roller 16. Here, the transfer material P is conveyed again at a timing such that the leading end of the transfer material P and the leading end of the image coincide.

On the other hand, the photosensitive drum 1 is driven by driving means (not shown).
, And is charged at a predetermined polarity and potential by the charging roller 2 to which a predetermined charging bias is applied. Then, image exposure with laser light is given to the charged photosensitive drum 1 by the exposure device 3 to form an electrostatic latent image corresponding to a first color component image (for example, a yellow component image) of a target color image. Is done. Next, the electrostatic latent image is developed by the yellow developing device 4Y of the developing device 4 with the first color yellow toner.

The first type formed and supported on the photosensitive drum 1
The yellow toner image of the color is applied to the primary transfer roller 6 and the pressure at the primary transfer roller 6 in the process of passing through the transfer nip (primary transfer portion) between the photosensitive drum 1 and the intermediate transfer belt 5. The primary transfer is performed on the intermediate transfer belt 5 by the electric field generated by the primary transfer bias. Hereinafter, similarly, the magenta developing device 4M and the cyan developing device 4M
C, a second color magenta toner image formed and carried on the photosensitive drum 1 by the black developing device 4Bk,
The color cyan toner image and the fourth color black toner image are sequentially superimposed and transferred onto the intermediate transfer belt 5 to form a composite color toner image corresponding to the target color image.

Then, the transfer material P is fed to the transfer nip (secondary transfer section) between the intermediate transfer belt 5 and the secondary transfer roller 7 at the timing described above. At this time, a secondary transfer bias is applied to the secondary transfer roller 7, and the composite color toner image is transferred from the intermediate transfer belt 5 onto the transfer material P.

The transfer material P on which the composite color toner image has been transferred is conveyed to a fixing device 9 by a conveyance guide member 8, and
A color visible image is permanently fixed on the transfer material P by heating and pressing by the fixing roller 9a and the pressing roller 9b. The transfer material P is discharged onto a discharge tray 18 via a pair of discharge rollers 17a, 17b, and 17c.

In the apparatus main body 19 of the above-described image forming apparatus, toners (yellow toner,
There is provided a toner amount detection device for independently detecting each remaining amount of magenta toner, cyan toner, and black toner).

FIG. 2 is a configuration diagram showing an example of a light transmission type toner amount detecting device for detecting the remaining amount of toner according to the present embodiment. The toner amount detection device is provided near the toner cartridge 101 (see FIG.
It is provided on the side.

In this figure, reference numeral 20 denotes a transistor, 2
1 is a current limiting resistor, and 22 is a light emitting element (LED in this embodiment). Reference numeral 23 denotes a detection resistor, reference numeral 24 denotes a phototransistor as a light receiving element, and reference numeral 25 denotes a transistor for amplifying a detection current of the light receiving element (phototransistor). The base of the transistor 20 on the light emitting element 22 side is connected to an output port of a control device (CPU) 27, and emits light when the output port is set to Hi or Lo. Light (infrared light) emitted from the light emitting element 22
Transmits through the toner T, which is a light shielding object in a toner cartridge (not shown), and enters the light receiving element 24.

The output of the light receiving element 24 is input to an input port of the control device 27 or an A / D converter (not shown). In the case of the input port of the control device 27, the threshold value is hardware-based. Will be decided. Also, A
When inputting to the / D converter, the threshold value is determined in advance. The light receiving signal of the light receiving element 24 is transmitted to the control device 2.
7 or an A / D converter, a few m
Sampling is performed at intervals of about s, the number of times exceeding the threshold value is counted, and when the counted number becomes equal to or greater than a predetermined value, it is detected that the toner amount is at the limit value.

In this embodiment, the light guides 26a and 26b are used to efficiently guide the light from the light emitting element 22 to the light receiving element 24. This is made of a resin such as transparent acrylic or polycarbonate, which has a very high transmittance and a high formability, and receives the light emitted from the light emitting element 22 through a toner cartridge (not shown) using the total internal reflection. It leads to the element 24.

Then, as described in the conventional example, a toner cartridge (not shown) is inserted into the apparatus main body, the toner cartridge is locked according to the operation procedure of the apparatus main body, and the door of the apparatus main body is closed. Is turned on to perform an initialization process.

At this time, the toner amount in the toner cartridge is detected by the toner amount detecting device described above. In the toner amount detecting device according to the present embodiment, the light emitting element 2
The light emission of No. 2 is performed immediately after the replacement of the new toner cartridge, and the number of prints until the next toner amount is measured is set according to the toner amount measured based on the light receiving signal of the light receiving element 24 at that time.

That is, as shown in FIG. 3, when the remaining amount of toner is detected (upper side of FIG. 3), assuming that the toner amount (remaining toner amount) is 100% in the first measurement, the following is performed. Increase the interval until the toner amount is detected. For example, in FIG. 3, from the detection of the first toner amount A ₁ to the next toner amount A ₂
Is detected after printing several hundred sheets, and thereafter, the interval until the next toner amount detection is shortened (the number of prints until the next toner amount detection is reduced), and the frequency of toner amount detection is increased. .

[0044] Thus, to increase the interval from the first toner quantity A ₁ detected up next toner quantity A ₂ detects, when the toner amount (remaining toner) A ₃ detects 50%, until the next detection The number of prints is reduced, and the detection is performed in a short time.
Further, the toner amount (toner remaining amount) is detected at 30% and 20%, and the interval is narrowed. When the toner amount becomes 20% or less, the detection is performed at the same interval as the normal detection timing. At this time, the light emission timing of the light emitting element 22 also corresponds to the toner amount detection timing.

The detection of the integrated amount of waste toner after image formation (lower side in FIG. 3) can be performed in the same manner. In this case, the amount of waste toner (amount of waste toner) increases as the amount of waste toner is integrated, contrary to the above-described detection of the remaining amount of toner.

As described above, in the present embodiment, the light emission time of the light emitting element 12 is reduced by increasing the toner amount detection interval at first (the number of prints until the next toner amount detection is increased). As the amount of toner approaches the limit value (0% for toner remaining amount detection, 100% for waste toner amount detection), the interval until the next toner amount detection is shortened, By increasing the frequency of toner amount detection, accurate measurement near the limit value of the toner amount can be performed.

<Embodiment 2> FIG. 4 is a block diagram showing a toner amount detecting apparatus according to the present embodiment.

In this figure, reference numeral 201a denotes a light emitting unit;
1b is a light emission control unit, 202 is a toner cartridge, 20
3 is a light receiving unit, 204 is an A / D converter, 205 is an amplitude detecting unit, 206 is a threshold value comparing / counting unit, and 207 is a comparing and error calculating unit.

In this embodiment, the light emitting section (light emitting element) 2
The light emitted from 01a passes through the toner in the toner cartridge 202 and enters the light receiving unit 203. Light receiving unit 2
The light receiving signal 03 has, for example, a waveform as shown in FIG. A portion near the power supply voltage Vcc is a stirring rod or a window (not shown) (light receiving window and light emitting window) in the toner cartridge 202.
Is a region that is shielded from light by a wiper that wipes off the light, and a portion where a low voltage is output allows light to pass through and the light-receiving part (light-receiving element)
203 is incident.

The light receiving output from the light receiving section 203 is represented by A
After binarization by the / D converter 204, in the related art, the threshold voltage comparing / counting unit 206 compares and calculates the detection voltage (light receiving signal) with a preset threshold value, and as a result, exceeds the threshold value. If this is the case, the count data is increased by one, but the windows (light-receiving window and light-emitting window) are made of toner.
If the light-emitting element and the light-receiving element become contaminated, the amount of transmitted light decreases, so that the detection voltage (light-receiving signal) does not drop below a preset threshold value, causing an error in the count value.

In order to avoid this, in the present embodiment, after the light receiving output from the light receiving section 203 is binarized by the A / D converter 204, the amplitude (pulse width) is detected by the amplitude detecting section 205 and compared. The error calculator 204 compares and calculates the pulse width of the reference value of the light reception output of the light receiver 203 set in advance, and inputs the obtained error information to the light emission controller 201b.

FIG. 6 shows a light emission control section 2 for inputting the error information and controlling the light emission amount of the light emitting section (light emitting element) 201a.
01b is a circuit diagram. In this figure, 30 is a switching control circuit, 31 is a transistor which is a switching element for turning on and off, 32 is a capacitor, 33 is an inductor, and 34 is a resistor. The resistor 34 is for preventing the maximum current from exceeding the rating of the light emitting unit (light emitting element) 201 and for preventing the temperature of the light emitting element from rising. Note that the resistor 34 may be omitted depending on the requirement of the ripple.

In the present embodiment, the switching control circuit 30 and the transistor 31 perform switching width control of the current from the power supply voltage Vcc based on the input error information.
2, the inductor 33, and the resistor 34 rectify the current to obtain a desired current, and the light emitting unit (light emitting element) 201.
The light emission amount of a is controlled so that the light receiving signal of the light receiving unit (light receiving element) 203 becomes constant.

As described above, in the present embodiment, by controlling the light emission amount of the light emitting unit (light emitting element) 201a so that the light receiving signal of the light receiving unit (light receiving element) 203 is constant,
The toner amount can always be accurately detected.

<Embodiment 3> FIG. 7 is a schematic sectional view showing a toner amount detecting apparatus according to the present embodiment. In addition,
The same members as those of the conventional toner amount detecting device shown in FIG. 9 are denoted by the same reference numerals, and duplicate description will be omitted.

In this embodiment, the position detecting sensor 117 for detecting the position of the stirring rod 106 for stirring the toner is provided, and the other structure is the same as that of the conventional toner amount detecting device shown in FIG. is there.

The stirring rod 1 rotated by the position detection sensor 117
When the position of No. 06 is detected, as shown in FIG.
A synchronization pulse is output according to the rotation cycle (stirring cycle) of No. 6, and the synchronization pulse signal is input to the light emission control unit 120 of the light emitting element 105. The light emission control unit 120 causes a current (light emitting element current) to flow to the light emitting element 105 for a predetermined time based on the input synchronization pulse signal to emit light.

The light emission control unit 120 samples the output (light reception signal) from the light receiving element 102 that receives the light transmitted through the toner in the toner cartridge 101 (the sampling cycle is about several ms), and the light emitting element 105 The number of times the reference threshold value is exceeded during the light emission time is counted, and when the counted number exceeds a predetermined value, it is detected that the toner amount is the limit value. Actually, the measurement is performed twice, and when it is detected twice consecutively, it is determined that the limit value has been reached, an operator call is instructed, and the user has no toner remaining or is abolished through display on the operation panel or the like. Notifies that the accumulated amount of toner is full.

As described above, in the present embodiment, the light emitting element 1
By synchronizing the light emission timing of 05 with the stirring cycle of the stirring rod 106, a decrease in the amount of light received by the light receiving element 102 due to toner contamination of the light receiving element 102 and the light emitting element 105 is prevented, and the toner amount is accurately detected. Detection can be performed.

[0060]

As described above, according to the toner amount detecting apparatus of the present invention, in the sensor for optically detecting the amount of toner, it is possible to extend the life of the light emitting element.
It is possible to correct the influence of a decrease in the amount of light received by the light receiving element due to the toner adhering to the light emitting element, the light receiving element, or any of the optical paths therebetween due to toner leakage or scattering, and to always accurately detect the toner amount.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a toner amount detection device of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating detection of a toner amount according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing a toner amount detection device of the image forming apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a diagram showing a light receiving signal according to the second embodiment of the present invention.

FIG. 6 is a circuit diagram showing a light emission control unit of the toner amount detection device according to the second embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a toner amount detection device of the image forming apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a diagram showing a light receiving signal, a synchronization pulse signal, and a light emitting element current signal in Embodiment 3 of the present invention.

FIG. 9 is a schematic sectional view showing a toner amount detecting device of a conventional image forming apparatus.

FIG. 10 is a schematic sectional view showing a toner amount detecting device of a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 20 transistor 21 current limiting resistor 22 light emitting element 23 detection resistor 24 light receiving element 25 transistor 27 control device (control means) 30 switching control circuit 31 transistor 32 capacitor 33 inductor 34 resistor 101 toner cartridge 102 light receiving element 103 light receiving side window 104 light emitting side Window 105 Light-emitting element 106 Stirring bar (stirring member) 107 Wiper 108 Fin 109 Sleeve 112 Bearing unit 114 Gear 115 Mechanical input unit 116 Boss 117 Position detection sensor 118 Rotating sleeve 120 Light emission control unit (control means) 201a Light emission unit 201b Light emission control Unit 202 toner cartridge 203 light receiving unit 204 A / D converter 205 amplitude detection unit 206 threshold value comparison / counting unit 207 comparison / error calculation unit

Claims (5)

[Claims] 1. A toner amount detecting device for optically detecting a toner amount used in an image forming apparatus using an electrophotography method, wherein a light emitting element for emitting light to a light transmitting portion of a container for storing the toner. A light-receiving element that receives light transmitted through the container; and a control unit that detects an amount of toner in the container based on a light-receiving signal output from the light-receiving element. A toner amount detecting device for an image forming apparatus, wherein subsequent toner amount detection is performed at predetermined intervals based on the detected toner amount. 2. The toner amount detecting device according to claim 1, wherein said detecting means shortens an interval until a next toner amount is detected as the toner amount approaches a detection limit value. 3. The toner amount detecting device for an image forming apparatus according to claim 1, wherein said detecting means changes light emission timing of said light emitting element in accordance with the number of images formed by said image forming apparatus. 4. A toner amount detecting device for optically detecting the amount of toner used in an image forming apparatus using an electrophotographic method, wherein a light emitting element for emitting light to a light transmitting portion of a container containing the toner is provided. And a light receiving element that receives light transmitted through the container; and a control unit that controls light emission of the light emitting element. The control unit has a pulse width of a light receiving signal output from the light receiving element. Comparing the pulse width of a preset reference value with the pulse width, calculating the difference, and controlling the light emission amount of the light emitting element based on the calculation result so that the light receiving signal of the light receiving element is constant. A toner amount detecting device of the image forming apparatus. 5. A toner amount detecting device for optically detecting a toner amount used in an image forming apparatus using an electrophotographic method, wherein a light emitting element for emitting light to a light transmissive portion of a container storing the toner. And a light-receiving element that receives light transmitted through the inside of the container; and a control unit that controls light emission of the light-emitting element. The control unit controls the light-emission timing of the light-emitting element, The light emitted from the light emitting element is synchronized with a stirring cycle of a stirring member for stirring toner in an optical path incident on the light receiving element or a cycle of wiping a window provided on a light transmitting surface of the container. A toner amount detecting device of an image forming apparatus.