JP3400588B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
More specifically, it relates to a toner replenishing device used in an image forming apparatus using a two-component developer.

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a copying machine, a printer or a facsimile machine uses an electrophotographic copying system. In the electrophotographic copying method, an electrostatic latent image is formed on a photosensitive member which is a uniformly charged image carrier by exposure or optical writing, and the electrostatic latent image is mixed with, for example, a magnetic carrier and toner. A two-component developer is used to transfer a visible image-processed image with toner to a recording paper or the like to obtain a copy. As an example of an image forming apparatus using a two-component developer, a case where a drum-shaped photoreceptor is used will be described. There is a configuration shown in FIG. The printer shown in FIG. 20 is configured to irradiate a dot-shaped spot in the main scanning direction and the sub-scanning direction of the photosensitive drum with a laser beam to form an electrostatic latent image.

In FIG. 20, a photosensitive drum 1 is provided inside the printer so as to be rotatable in the direction of the arrow shown in the figure. Around the photosensitive drum 1, a charging device 2, which is a means for executing an image forming process along the rotation direction,
An optical writing device 3, a developing device 4, a transfer / separation device 5, and a cleaning device 6 are arranged. The charging device 2 is provided to uniformly charge the photosensitive drum. The optical writing device 3 includes a semiconductor laser 3A, a rotary polygon mirror 3B, and f.
The / θ lens 3C and the scanning mirror 3D are provided. The semiconductor laser 3A is controlled to emit light by the laser driver 3E, and the laser beam emitted from the semiconductor laser 3A is incident on and reflected by the rotating polygon mirror 3B to be scanned in the main scanning direction and the sub-scanning direction on the photosensitive drum 1 to be exposed. An electrostatic latent image corresponding to the writing information is formed on the body drum 1 by combining dot-shaped spots. The developing device 4 is a visible image processing means constituted by a magnetic brush developing device using a two-component developer constituted by magnetically adsorbing toner frictionally charged to a magnetic carrier. Therefore, in the developing container 4A, a developing sleeve 4B that carries a magnetic brush from the side close to the photoconductor drum 1 to bring the magnetic brush into contact with the electrostatic latent image on the photoconductor drum 1, and agitate and agitate the toner. Stirring members 4C and 4D for charging and a toner replenishing device 4E are arranged. As shown in FIGS. 20 and 21, the developing device 4 is configured such that the stirring members 4C and 4D are arranged in parallel in the horizontal direction to reduce the occupied area in the height direction, and the toner replenishing device 4E. The toner replenishment path from is also set in the direction in which it is fed from the side end portion, not from above the stirring members 4C and 4D. As a result, the developer agitated and adsorbing the charged toner moves in the horizontal direction, and the amount of the magnetic brush carried on the developing sleeve 4B is regulated by the doctor member 4F facing the peripheral surface of the developing sleeve 4B. It has become Let 's that.

Toner replenishing device 4E forming toner replenishing means
Is a toner replenishment control means composed of a replenishment tank 4E1 and a rotatable replenishment feeding member 4E2 arranged at the opening of the tank 4E1.
Are provided so as to be replaceable, and the replenishment feeding member 4
E2 is configured to deliver a required amount of toner by setting a rotation amount by drive control by an image forming apparatus control circuit for executing toner density control, which will be described later.

As an example of the structure of the developing device 4, there are structures shown in FIGS. 22 and 23. 22 and 23, the developing device 4 includes stirring members 4C and 4D.
A screw is used as each stirring member 4C, 4
The rotation direction of D is set to a direction in which the developer can be transferred in directions opposite to each other with stirring. In FIG. 23, the stirring screw 4C located on the side having an opening communicating with the toner supply tank 4E1 at one end in the axial direction (hereinafter, this screw is referred to as a supply stirring screw) is
As shown in FIG. 23, the length of the other stirring screw (hereinafter, this screw is referred to as a developing stirring screw) 4D is longer than that of the other stirring screw 4D, and the replenished toner is indicated by an arrow F.
As shown in FIG. 5, the developing stirring screw 4D can be transported toward the other end in the axial direction. The developing device 4 accommodates a supply stirring screw 4C and a developing stirring screw 4D with the partition wall 4A1 as a boundary, and the longitudinal ends of the partition wall 4A1 parallel to the axial direction of each stirring screw are cut off. The space in which the replenishment stirring screw 4C and the development stirring screw 4D are accommodated is communicated with each other. As a result, the replenished toner is transported while being agitated in the direction away from the opening by the replenishment stirring screw 4C, and is agitated for development through the portion where the partition wall 4A1 is cut off, as shown by the alternate long and short dash line in FIG. Screw 4D
Enters the space in which is stored, and is moved in the axial direction of the developing sleeve 4B while being stirred by the developing stirring screw 4D. Since the developing stirring screw 4D is arranged so as to face the developing sleeve 4B, the magnetic brush carried on the agitated surface is not connected to the developing sleeve 4B.
Can be attached to the peripheral surface of the.

The transfer / separation device 5 is composed of a charging device, and the transfer charging device is the developing device 4.
At the same time, by charging the toner attached to the latent image portion of the photosensitive drum 1 with a polarity opposite to the charging polarity, the transfer material S such as recording paper fed from a paper feeding device (not shown)
The visible image on the photosensitive drum 1 is electrostatically adsorbed and transferred. The separation charging device performs charging for electrically neutralizing the transfer material S charged by the transfer charging device, and facilitates separation of the transfer material S from the photosensitive drum 1. .

The cleaning device 6 is provided with a scraping member and a blade for removing the toner remaining on the surface of the photosensitive drum 1 after the transfer, and
The toner removed from the surface is collected in a waste toner tank (not shown) or transferred to the developing device 4 or the replenishment tank 4E1 for reuse.

In the printer having the above-mentioned structure, after the charging device 2 uniformly charges the photosensitive drum 1, the writing device 3 scans to form an electrostatic latent image on the photosensitive drum 1. This electrostatic latent image is subjected to a visible image processing by the toner in the magnetic brush carried by the developing sleeve 4B of the developing device 4 to form a visible image, and the transfer charging device in the transfer / separation device electrostatically charges the recording paper S. The image is transferred and made to be easily peeled off from the photoconductor drum 1 by the separation charging device, peeled off from the photoconductor drum 1 by a separation member (not shown), and image-fixed by a fixing device (not shown).

In the developing device 4, the toner in the developer is consumed to develop the electrostatic latent image on the photosensitive drum 1.
Therefore, the density of the visible image formed on the photosensitive drum,
The so-called toner density may change with time and may not reach the predetermined density.

Therefore, conventionally, the toner concentration in the developer in the developing device 4 is monitored, and when the toner concentration is insufficient, the toner is replenished. It is necessary to detect the toner concentration for replenishment, and as a method therefor, there has been proposed a method of measuring the rate of change of the inductance of a detection coil installed in the developer (for example, Japanese Patent Publication No. 63-2
8305, JP-A-58-55952). As a configuration using this method, as shown in FIG. 20, the toner concentration detection sensor 10 is installed in the developing device 4, and the toner concentration in the developer in the developing device 4 is used as the voltage value V _TC in the image forming apparatus. There is one that is adapted to output to the control device 11. In this configuration, it is determined whether or not the toner is to be replenished and the amount of replenishment is set according to the density detected by the image forming apparatus control circuit 11 for toner concentration control, and the toner replenishment is performed based on the result. A drive signal is output to the replenishment feeding member 4E2 of the device 4E. The image forming apparatus control circuit 11 which constitutes an image forming apparatus control unit for executing toner density control is a circuit which performs not only control related to toner replenishment but also overall control related to image formation, and also emission control of the semiconductor laser 3A. I am supposed to do it. Therefore, the image forming apparatus control circuit 11 for executing the toner density control outputs the information signal input from the image reading apparatus (not shown) to the writing control unit 12, and the light emission control signal based on the signal is output to the laser driver. It is output to 3E to set the light emission timing and light emission amount of the semiconductor laser.

In the image forming apparatus having such a structure, when copying is performed and the toner in the developer is consumed, the toner corresponding to the consumed amount is replenished.
As the supply method, the procedure shown in FIG. 24 is executed. In FIG. 24, the toner density is detected and the detected potential (V _TC ) is obtained. If the detected potential (V _TC ) is V0 or less of the preset replenishment determination potential, toner replenishment is not performed, and again after T1 (seconds).
Toner density detection is executed. Above detection potential (V _TC )
However, if V0 or more and V1 or less of the preset replenishment determination potential, a small amount (L) of toner is replenished. The subsequent toner concentration detection timing is set after T2 (seconds) in consideration of the time when it is considered that the supplied toner is sufficiently mixed during development.
When the detected potential (V _TC ) is V1 or more and V2 or less of the preset replenishment determination potential, medium amount (M) toner replenishment is executed. The toner concentration detection timing thereafter is T2 in consideration of the time when it is considered that the supplied toner is sufficiently mixed during development.
(Seconds) later. When the detected potential (V _TC ) is V2 or more of the preset replenishment determination potential, a large amount (H) of toner replenishment is executed. The toner concentration detection timing after that is T time in consideration of the time when the replenished toner is considered to be sufficiently mixed during development.
It is set after 2 (seconds). However, in general, even when the toner concentration is detected by using the above method, there is a certain time lag between the time when the replenished toner is agitated and the time when the replenished toner is carried on the developing sleeve. It cannot be said that the image density on the photosensitive drum 1 can be optimized just because the image formation is started. Therefore, when only the toner density in the developer is measured, it does not mean that the density control that can correct the actual image density is performed.

Therefore, in controlling the toner density to a standard value, a method has been proposed in which, in particular, the toner consumption amount is predicted and the toner supply amount is corrected (for example,
JP-A-2-220082). In the invention described in the above publication, a blackened area ratio detecting means for measuring the blackened area ratio of the original is provided, and the detection value from the toner density detection sensor is corrected based on the detection signal from the blackened area ratio detecting means. It is supposed to do.

[0013]

However, in the invention described in the latter publication, the reflected light of a part of the original on the platen glass forming the original placing table is detected by the light receiving element through the optical system and reflected. Since the histogram is obtained by comparing the light quantity with the determination criteria one by one, the configuration becomes complicated. Moreover, no consideration is given to changes in the use environment of the developer and the developing device or changes with time. Therefore, when only the blackened area ratio on the original is simply used as a reference, the carrier that constitutes a part of the developer depending on the actual consumption amount and the environmental conditions when replenishing the toner suitable for development or It is difficult to accurately set the toner replenishment amount because the change in the characteristics of the photoconductor is not taken into consideration. Moreover, in recent years, an image forming apparatus equipped with a scanner as an image input device has been provided, and in this case, since the driving time of the scanner is related to the deterioration of the photoconductor with time, It has been found to affect consumption. Therefore, the invention described in the above publication has a problem that it is impossible to set an appropriate amount of toner replenishment when such an image input device is attached.

In addition, when a screw structure is used as the stirring member of the developing device, a certain amount of time is required until the replenished toner reaches the developing sleeve. In the case of alternately developing high and low images, the replenishment timing cannot be immediately adjusted, so that replenishment is not performed according to the amount of toner consumed for each image density, and the developed image density There was a problem that unevenness was likely to occur.

In view of the above-mentioned problems in the conventional image forming apparatus, an object of the present invention is to quickly supply toner according to the amount of toner consumed with respect to the image density, and the environment in which the toner is used and the developing device. Another object of the present invention is to provide an image forming apparatus that can always set a stable toner density regardless of the change with time of the image input apparatus.

[0016]

To achieve this object, the invention according to claim 1 is directed to an image carrier and an electrostatic latent image formed on the image carrier by irradiating and projecting scanning light. Equipped with means for processing a visible image with a two-component developer consisting of toner and carrier, and toner replenishing means for detecting toner concentration in the developer and executing toner replenishment control based on the detection result. in the images forming apparatus, horizontal
So that the developer can be transferred in opposite directions.
One of the screws as juxtaposed stirring members
One side is longer than the other side, and toner is added to the lengthened part.
The toner fed from the feeding member is fed to the other end in the axial direction.
Means for detecting a developing apparatus having a structure for transferring the latent image writing area ratio by the scanning beam irradiation or projected to the means for forming the electrostatic latent image on said image bearing member toward said developer Toner concentration in agent and writing of latent image
The area ratio is entered, and the toner replenishment is fed out.
An image forming apparatus control circuit for controlling the operation of the members,
The image forming apparatus control circuit controls the toner concentration in the developer.
The latent image is written when replenishing the toner according to the change in
Correct the toner replenishment amount according to the included area ratio
The drive status and current status of the toner replenishment feeding member.
When the developer consumed in the image area reaches the development area again
Make sure that the developer contains replenished toner
It is characterized in that the toner supply start and end timings are set.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the image forming apparatus control circuit comprises:
Of toner supply start and end timing
The fixed area is the development area that moves along the axial direction of the screw.
The developer whose toner has been consumed by increases the axial length above.
At the axial position of the screw
Timing to reach the position where toner is replenished by the roller member
The feature is that it is performed in accordance with.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the image forming apparatus described above, the toner replenishment feeding
The toner that is fed from the roller member starts and ends as described above.
When the amount is fixed during the timing, or at the start and
And is changed at the end .

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

According to the invention described in claims 1 and 2 , in the horizontal direction
Arranged side by side so that the developer can be transferred in opposite directions.
One of the screws as a stirring member is
And replenish the toner supply to the lengthened part.
Direct the toner delivered from the projecting member to the other end in the axial direction.
For developing devices equipped with a structure for transferring
Toner density in the developer when the toner density of
When replenishing toner according to changes in the
After correcting the toner replenishment amount according to the area ratio,
Driving state and developing area of the toner replenishment feeding member
When the developer consumed in the area reaches the developing area again,
Toner that contains replenished toner in the developer
Current supply start and end timings are set.
Newly replenished toner is contained in the developer that has reached the image area.
Included in the developing area
It is possible to prevent uneven image density that occurs when
It

According to the third aspect of the invention, at the start of development,
And the tendency for toner consumption to decrease at the end
Waste toner by reducing the toner supply amount
Do not replenish the toner to keep the toner concentration constant.
Can be realized.

[0026]

[0027]

[0028]

[0029]

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 is a diagram showing a system configuration of an image forming apparatus showing an embodiment of the present invention. In the drawings after FIG. 1, the same components as those shown in FIG. 20 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a basic system configuration of an image forming apparatus according to the present invention. In this configuration, a correction circuit 20 is connected to an image forming apparatus control circuit 11 for controlling toner density. The correction circuit 20 has registered therein a reference value relating to adjustment of toner consumption, and by taking in and comparing the registered reference value with the condition for reducing the toner in the developer, the inside of the developing device 4 can be compared. The toner replenishment amount obtained from the toner concentration detection value is corrected, and then a signal (S _OU ) relating to the corrected toner replenishment amount is output to the image forming device control circuit 11 The toner replenishing amount, the replenishing time, and the replenishing timing of the toner replenishing device 4E are adjusted. Toner reduction conditions used in the correction circuit 20 include the size of the image forming area that affects toner consumption, the temperature and humidity in the apparatus, the number of times the photosensitive drum 1 is driven and the number of times of transfer, and the like. It is used as a parameter. To determine the size of the image forming area, the number of dots of the laser beam and the light emission time are used as parameters.

An embodiment using each condition will be described below.

In FIG. 1, the toner density detection sensor 10 and the writing dot counting section 21 installed in the developing device 4 are connected to the input side of the correction circuit 20, and the image forming apparatus control circuit 11 is connected to the output side. Are connected. The correction circuit 20 is adapted to transfer the write dot count number STD and also to receive the detection voltage value V _TC from the toner concentration detection sensor 10. The correction circuit 20 performs the correction process shown in FIG. 2 on the toner replenishment amount based on the detected voltage value V _TC from the toner concentration detection sensor 10, and indicates the toner replenishment amount determined by this process. The signal (S _OU ) is output to the image forming apparatus control circuit 11. As a result, in the image forming apparatus control circuit 11, the replenishment feeding member 4E2 corresponding to the corrected toner replenishment amount.
A signal ( _STA ) for controlling the driving state of the device is output.

In FIG. 2, the toner concentration detecting sensor 10
Outputs a voltage value (V _TC ) corresponding to the toner density detection value in the developing device 4 to the correction circuit 20. The correction circuit 20 compares the voltage value ( _VTC ) with the reference voltage value (V1). In this case, the reference voltage value (V1) corresponds to the surface potential of the photoconductor that gives an appropriate value of the toner concentration, among the surface potentials of the photoconductor that affect the toner adhesion amount per predetermined area. . The same applies to the reference voltage values listed below, but the reference voltage values are changed to numerical values that can increase the image density stepwise. In the comparison between the reference voltage value (V1) and the density detection voltage value ( _VTC ), when the density detection voltage value ( _VTC ) is smaller, the number of writing dots is compared. The number of dots is compared with the writing dot count section 2
The number of write dots counted from 1 (S _TD ) is the correction circuit 2
It is compared with the reference number of dots registered in 0. The reference number of dots (D1) in this case corresponds to the number of dots where the density of the image formed at the surface potential corresponding to the reference voltage value becomes an appropriate value. The same applies to the number of reference dots described below, but the number is changed so that the image density can be increased with the change of the reference voltage. When the reference dot number (D1) is compared with the write dot count number (S _TD ) and the reference dot number or less, toner is not replenished (toner replenishment amount = 0). When the number of written dots (S _TD ) is equal to or larger than the reference number of dots (D1), the toner replenishment amount is corrected to a small amount (L) (replenishment amount = L).

The density detection voltage value (V _TC ) is the reference voltage value (V
When it is 1) or more, it is compared with the reference voltage value (V2) of the next stage. The concentration detection voltage value (V _TC ) is the reference voltage value (V
If it is smaller than 2), the count number of writing dots (S _TD ) is compared with the reference dot number (D2). If it is smaller than the reference dot number (D2), the toner supply amount is corrected to a small amount (L). (Correction amount = L). If the result of comparing the number of written dots (S _TD ) with the reference dot number (D2) in the next stage is equal to or greater than the reference dot number (D2), the toner replenishment amount is corrected to the medium amount (M). (Correction amount = M).

The density detection voltage value (V _TC ) is the reference voltage value (V
When it is 2) or more, it is compared with the reference voltage value (V3) of the next stage. The concentration detection voltage value (V _TC ) is the reference voltage value (V
If it is smaller than 3), the number of written dots (S _TD ) is compared with the reference dot number (D3) of the next stage, and if it is smaller than the reference dot number (D3), the toner replenishment amount is a medium amount ( M) is corrected (correction amount = M). If the result of comparing the count number (S _TD ) of the write dots with the reference dot number (D3) is equal to or larger than the reference dot number (D3), the toner supply amount is unconditionally corrected to a large amount (H). (Correction amount =
H).

Reference voltage values V1 to V used for the above comparison
The relationship of 3 is set to V1 <V2 <V3, and the relationship of the reference dot numbers D1 to D3 is set to D1 <D2 <D3. However, the reference dot number may be D1 = D2 = D3 depending on the configuration of the image forming apparatus,
Further, when the number of written dots is extremely small with respect to the reference number of dots, it is possible to correct the toner replenishment amount to a small amount in order to prevent the harmful effects such as toner scattering.

The toner supply amount used in this embodiment is
A small amount (L) is set to 2.5 g, a medium amount (M) is set to 5.0 g, and a large amount (H) is set to 10.0 g with respect to the developer of 500 g. However, since this amount itself is a value peculiar to the apparatus, it can be set according to the configuration of the apparatus, the type of the developer, and the model such as the amount of the developer.

When the correction amount of the toner replenishment amount is determined in this way, the toner replenishment timing is set.
The toner replenishment timing means a toner replenishment start timing and a toner replenishment timing, and the following procedure is used.
FIG. 3 shows a developing device 4 having the configuration shown in FIG. 23. In this developing device 4, the region that contributes to the development of the electrostatic latent image formed on the photosensitive drum 1 is the developing device. It is a range indicated by symbols P1 and P2 in the axial direction of the stirring screw 4D for use. Therefore, in order to keep the concentration of the developer used for the development constant, it is necessary to replenish the toner consumed in the developer in the above area.

Therefore, at least at the time when the developer located at the point P2 moves to the point P1, it is consumed in the above-mentioned region in the developer moving to the point P2 by the replenishment stirring screw 4C. Replenishment of toner is necessary to keep the toner density in the area constant. For this reason, at least P1 with respect to the point indicated by the reference symbol P3 on the accommodation space side of the replenishment stirring screw 4C among the openings communicating with the space accommodating each stirring screw.
If newly replenished toner is present at the time when the developer located at the point moves, the above-mentioned is performed while the developer moves from the point P2 to the point P1 and contributes to the development. After the developer located at the point P2 moves to the point P1, the developer newly moving from the point P2 to the point P1 contains the replenished toner.

FIG. 4 is a timing chart showing the toner replenishment start timing and the toner replenishment timing based on the above premise, and the meanings of the respective symbols are as follows. T10: Time for the developer to move from the P1 point to the P3 point T11: Time for the developer to move from the P2 point to the P3 point T12: Position P4 to P3 point opposite to the supply opening in the axial direction of the supply stirring screw 4C If the toner replenishment timing corresponds to the development bias on / off time corresponding to the development start / end time, the toner replenishment start timing is from the time the development bias is turned on (T
It is set at the time when the relationship of 10-T12> 0) is established. As a result, new replenishment toner can be mixed in the developer when the developer moves from the point P1 to the point P3. The above relationship may be T10 = T13, which means that new replenishment toner can be mixed into the developer when the developer moves from the point P1 to the point P3.

The toner replenishment end time is set to the time when the relationship of (T11-T12> 0) is established from the time when the developing bias is turned off. As a result, the developer located at the point P2 consumes the toner that contributed to the development, and the developer P3 is consumed.
During subsequent development at the time of the move to the point, the developer containing the new supply toner from point P2 can developing sleeve and pair countercurrent to <br/> Rukoto. Regarding the timing of starting toner replenishment, T
In the case of 10 <T12 would toner replenishment is started earlier than the on-set of the developing bias. The toner replenishment timing described above may be configured such that a fixed amount can be replenished simply by on / off control, but since toner consumption generally tends to decrease at the development start timing and the development end timing, the toner replenishment timing tends to decrease. It is also preferable to change the replenishment amount so that the toner replenishment amount becomes small at the start and end of the replenishment, in order to realize the constant toner density without wasteful replenishment.

The total replenishment amount of toner in this case is the amount calculated from the written dot count number, and the amount obtained by dividing the total replenishment amount by the total time is the replenishment amount per unit time.
From this, referring to the supply amount per unit time,
The number of rotations of the replenishment feeding member 4E2 and each stirring screw is set. Incidentally, in this embodiment, although the time of developing bias on / off was equivalent at the beginning / end of the development, thereby corresponding on / off or the like of a clutch for operating the developing sleeve and the developing unit at the beginning / end of the developing In short, if the timing contributing to the development can be controlled, it is possible to control the toner replenishment timing based on the timing.

FIG. 5 shows a modified example of the configuration shown in FIG. 1. In this example, a writing time counting section 22 is provided in place of the writing dot counting section shown in FIG. There is. In FIG. 5, a write time counting section 22 is connected to the correction circuit 20 so that the write time count number STD is transferred. In addition, the correction circuit 2
0 indicates the detected voltage value V from the toner density detection sensor 10.
_{TC is} also input. In the correction circuit 20,
The toner replenishment amount based on the detected voltage value V _TC from the toner concentration detection sensor 10 is subjected to the correction process shown in FIG. 6, and a signal (S _OU ) for instructing the toner replenishment amount determined by this process. Is output to the image forming apparatus control circuit 11. As a result, the image forming apparatus control circuit 11 outputs a signal ( _STA ) for controlling the driving state of the replenishment feeding member 4E2 that matches the corrected toner replenishment amount.

In FIG. 6, the toner concentration detecting sensor 10
Outputs a voltage value (V _TC ) corresponding to the toner density detection value in the developing device 4 to the correction circuit 20. The correction circuit 20 compares the voltage value ( _VTC ) with the reference voltage value (V1). The reference voltage value (V1) in this case corresponds to the surface potential of the photoconductor that gives an appropriate value of the toner density per predetermined area, as in the above-described embodiment. The same applies to the reference voltage values listed below, but the values are increased stepwise to increase the image density. Reference voltage value (V1)
When the density detection voltage value (V _TC ) is smaller than the density detection voltage value (V _TC ), the writing time is compared. The writing time is compared with the writing time counting unit 22.
The write time from is compared with the reference time (T1) registered in the correction circuit 20. Reference time (T1) in this case
Is equivalent to the time required to obtain the surface potential of the photoconductor at which the density of the image formed in the image area per predetermined area becomes an appropriate value. The same applies to the reference times listed below, but the values are changed in the direction of increasing the image density. In the comparison between the reference time (T1) and the writing time, if the writing time is the reference time (T1) or less, the toner is not replenished (toner replenishment amount = 0). When the writing time is equal to or longer than the reference time (T1), the toner replenishment amount is corrected to a small amount (L) (replenishment amount = L).

The concentration detection voltage value (V _TC ) is equal to the reference voltage value (V
When it is 1) or more, it is compared with the reference voltage value (V2) of the next stage. The concentration detection voltage value (V _TC ) is the reference voltage value (V
If it is smaller than 2), the writing time is the reference time (T
In contrast to 2), if it is less than the reference time (T2), the toner replenishment amount is corrected to a small amount (L) (correction amount = L).
When the result of comparing the writing time with the reference time (T2) of the next stage is the reference time (T2) or more, the toner replenishment amount is corrected to the medium amount (M) (correction amount = M).

The density detection voltage value (V _TC ) is the reference voltage value (V
When it is 2) or more, it is compared with the reference voltage value (V3) of the next stage. The concentration detection voltage value (V _TC ) is the reference voltage value (V
If it is smaller than 3), the writing time is compared with the reference time (T3) of the next stage. If the writing time is shorter than the reference time (T3), the toner replenishment amount is corrected to the medium amount (M). (Correction amount = M). When the result of comparing the writing time with the reference time (T3) is longer than the reference time (T3), the toner supply amount is unconditionally corrected to a large amount (H) (correction amount =
H).

Reference voltage values V1 to V used for the above comparison
The relationship of 3 is set to V1 <V2 <V3, and the relationship of reference times T1 to T3 is set to T1 <T2 <T3. However, the reference number of dots may be T1 = T2 = T3 depending on the configuration of the image forming apparatus, etc. Further, when the writing time is extremely short with respect to the reference number of dots, there is a problem such as toner scattering. To prevent this, it is possible to correct the toner supply amount to a small amount.

The toner supply amount used in this embodiment is
A small amount (L) is set to 2.5 g, a medium amount (M) is set to 5.0 g, and a large amount (H) is set to 10.0 g with respect to the developer of 500 g. However, since this amount itself is a value peculiar to the apparatus, it can be set according to the configuration of the apparatus, the type of the developer, and the model such as the amount of the developer.

When the replenishment amount is corrected in this way, the toner replenishment timing is set to the same state as that shown in FIG.

With respect to the embodiment having the above structure, the present inventor conducted an experiment on the change of the image density according to the correction result of the toner supply amount by the correction circuit 20, and obtained the result shown in FIG. The experiment result shown in FIG. 7 shows that the image density when the image area ratio is 5% and the image density when the image area ratio is 50% are alternately set to 10 sheets, and 200 sheets in total in the 1to1 mode. The results of the experiments are shown, the results indicated by the solid line are according to the present embodiment, and the results indicated by the chain double-dashed line are the results obtained by the conventional configuration shown in FIG. As is apparent from FIG. 7, in the case of the conventional configuration, immediately after the image area ratio is changed from 50% to 5%, the toner replenishment amount and timing cannot immediately respond to the toner consumption degree, and In the present embodiment, the density deviation is 0.1 or less and the maximum density deviation is 0.25 at maximum, and in the present embodiment, the density deviation is 0.1 or less. No state was observed, and a stable image density could be maintained.

In the above embodiment, the image forming apparatus using the laser beam as the writing apparatus 3 is targeted, but the present invention is not limited to such an apparatus, and the image area of the digital type using the LED is obviously used. It is also possible to target an analog image forming apparatus using a means for calculating the rate. The correction of the toner replenishment amount when the light emitting means is changed is the same as that in the above embodiment. With such a configuration, the writing device can be downsized and the image forming apparatus itself can be prevented from being upsized.

Next, an embodiment of the invention described in claim 2 will be described. The present embodiment is characterized in that the toner replenishment amount, replenishment time, and replenishment timing are set according to the size of the transfer material onto which the toner image is transferred.

FIG. 8 shows the developing device 4 shown in FIG.
The developing sleeve used in the developing device 4 is set so that its axial length corresponds to the maximum size of the transfer materials used for copying. As an example, in the case of an A3 size transfer material, the axial length is 297 m.
It is set to m. However, the transfer material used for copying is not limited to one that uses the entire area of the axial length of the developing sleeve. As an example, B4 size (257m
m) or the transfer material of A4 size is set with its longitudinal direction perpendicular to the axial direction of the developing sleeve (the length of the developing sleeve in this case is 210 m in the axial direction).
In m), development is performed in a range shorter than the axial length of the developing sleeve. For this reason, regions that do not contribute to the development occur at both ends or one end side in the axial direction of the developing sleeve, and when toner is replenished at the replenishment timing shown in FIG. 3, the development is performed immediately after the start of replenishment and immediately before the end of replenishment. Toner is replenished to the area that does not contribute to the development, the density in that area increases, and when developing to a transfer material of a size that newly uses the entire axial area of the developing sleeve, Density unevenness occurs in the direction.

Therefore, when developing a transfer material having a size smaller than the axial length of the developing sleeve, it is necessary to change the replenishment timing according to the size. The details will be described below with reference to FIGS. 8 and 9. If the moving area of the developer by the developing stirring screw D in the case of developing using the entire area of the developing sleeve in the axial direction is the range indicated by the symbols P1 and P2 in FIG. 3, a region shorter than the range. , Reference numerals P1 'and P2' in FIG.
When the range indicated by is used, the supply timing shown in FIG. 9 is set. The symbols in FIG. 9 have the following meanings. T20: Time for the developer to move from the P1 'point to the P3 point T21: Time for the developer to move from the P2' point to the P3 point The toner replenishment timing is based on the timing described in FIG. Assuming that the on / off time corresponds to the start / end of development, the toner replenishment start time is set to (T10-T2) with respect to the start time shown in FIG.
2) (seconds), and the toner replenishment end time is advanced by (T11-T21) (seconds) with respect to the end time shown in FIG. 4, and as shown in FIG. 9, the toner replenishment start time is From the time when the developing bias is turned on (T20-T
It is set when the relationship of 12) is established. The toner replenishment end time is from the time when the developing bias is turned off (T2
1-T12) is established when the relationship is established. The timing chart shown at the bottom of FIG. 9 is the timing chart shown in FIG. 4, and is shown in order to make it easier to understand the difference in timing from this embodiment.

As a result, the time until the developer is mixed with the newly supplied toner and the time until the developer mixed with the newly supplied toner and agitated face the developing sleeve. The contact time between the developing sleeve and the developer can be adjusted when the target is shorter than the entire area in the axial direction, and the toner supply consumed by the contact with the developing sleeve can be adjusted until the next contact with the developing sleeve. It will be completed in the meantime. In this case, the size of the transfer agent is detected by using a detection mechanism (not shown), a side edge guide position detection mechanism for manual feeding, or the like, and the above timing is corrected based on the detection result.

According to this embodiment, since the replenishment amount and the replenishment timing can be corrected in accordance with the developing range in the axial direction of the developing sleeve, wasteful replenishment of toner is prevented and the developing sleeve of the developing sleeve is prevented. It is possible to prevent a situation in which the developer concentration in the axial direction becomes uneven.

By the way, it is known that the amount of toner that moves from the developing device 4 toward the electrostatic latent image and adheres to the electrostatic latent image with the surface potential of the photosensitive member kept constant depends on the temperature. For example, 10 ° C 60% RH, 20 ° C 60% R
Comparing the case where the temperature changes at the same humidity such as H and 30 ° C. 60% RH, the toner adhesion amount per unit area on the photoconductor with respect to the surface potential of 500 V is
This is as shown in FIG. As is clear from FIG. 10, the toner adhesion amount increases in proportion to the temperature rise.
Therefore, if the toner density is set on the basis of the condition of 20 ° C. and 60% RH, the image density will inevitably decrease under this condition, and the image density will decrease under this condition. Will inevitably rise. In particular,
When the image density is increased, there is a possibility that a secondary problem may occur that the background of the photoconductor is stained. Therefore, it is necessary to maintain a constant toner density regardless of the temperature change.

FIG. 11 shows an embodiment in this case, and this embodiment is characterized in that the toner density detection result in the developing device 4 is corrected according to the temperature change in the device. The embodiment shown in FIG. 11 is based on the configuration of the embodiment shown in FIG. 1, and a temperature sensor 60 is arranged in the vicinity of the photosensitive drum 1, and the temperature sensor 60 is used for the correction circuit 2.
It is configured by connecting to 0. The correction circuit 20 has the configuration shown in FIG.
Similarly to the embodiment shown in FIG. 5, the detection voltage V _TC from the toner concentration detection sensor 10 installed in the developing device 4 and the write dot count number S _TD from the write dot count unit 21 are transferred. The output signal (V _TH ) from the temperature sensor 60 is input.

In the correction circuit 20, the detection voltage V _TC from the toner concentration detection sensor 10 and the write dot count unit 2
Based on the dot count number S _TD from 1, the process shown in FIG. 2 is performed, and the temperature shown in FIG.
The toner replenishment amount is corrected according to the temperature based on the relationship of the toner adhesion amount. Therefore, in addition to the correction result obtained by the process shown in FIG. 2, the reference concentration obtained from the relationship shown in FIG.
A signal (S) for correcting the toner replenishment amount based on the correction result is corrected so that the density at 0% RH is obtained.
_OU ) is output to the image forming apparatus control circuit 11. In this embodiment, when 20 ° C. 60% RH is used as a condition for obtaining the reference density, and when 10 ° C. 60% RH, the amount of toner replenishment corrected by the process shown in FIG. 2 is increased by 4%. In the case of 30 ° C. and 60% RH, the toner supply amount corrected by the process shown in FIG. 2 is reduced by 6%. According to this embodiment, as a result of correcting the toner replenishment amount under various temperature environments with respect to the reference temperature, the ID variation value of the image based on the Macbeth value is 0.25.
To 0.08.

The output signal from the temperature sensor 60 can be input to the correction circuit 20 via the image forming apparatus control circuit 11. In this case, as shown in FIG. 12, a signal input / output line is connected between the image forming apparatus control circuit 11 and the correction circuit 20 to output the output signal (V _TH ) from the temperature sensor 60 to the correction circuit 20. 11 as an input signal (S _IN ) to the image forming apparatus controller 11 as a feedback signal (S _OU ) that is the same as the case shown in FIG. Similar results are obtained. According to the present embodiment, a stable image density can be maintained regardless of the temperature change, so that stable image quality can be obtained without causing excessive supply or insufficient supply of toner or background stain.

It is known that the amount of toner that moves from the developing device 4 toward the electrostatic latent image and adheres to the electrostatic latent image with the surface potential of the photosensitive member kept constant depends on the humidity. For example, 20 ° C 30% RH, 20 ° C 60% RH, 20 ° C 9
When comparing the case where the humidity changes at the same temperature such as 0% RH, the toner adhesion amount per unit area on the photoconductor with respect to the surface potential of 500 V is as shown in FIG. As is clear from FIG. 13, the toner adhesion amount increases in proportion to the increase in humidity. Therefore, if
When the toner density is set on the basis of the condition of 20 ° C. and 60% RH, the image density is inevitably lowered under the condition, and the image density is inevitably exceeded under the condition. As a result, it will rise. In particular, when the image density is increased, there is a possibility that a secondary problem may occur in which the background of the photoconductor is stained. Therefore, it is necessary to maintain a constant toner density regardless of changes in humidity.

FIG. 14 shows an embodiment in this case, and this embodiment is characterized in that the toner density detection result in the developing device 4 is corrected according to the humidity change in the device. The embodiment shown in FIG. 14 is based on the configuration of the embodiment shown in FIG. 1, and a humidity sensor 70 is arranged in the vicinity of the photosensitive drum 1, and the humidity sensor 70 is used for the correction circuit 2.
It is configured by connecting to 0. The correction circuit 20 has the configuration shown in FIG.
Similarly to the embodiment shown in FIG. 5, the detection voltage V _TC from the toner concentration detection sensor 10 installed in the developing device 4 and the write dot count number S _TD from the write dot count unit 21 are transferred. The output signal (V _CU ) from the humidity sensor 70 is input.

In the correction circuit 20, the detection voltage V _TC from the toner density detection sensor 10 and the write dot count unit 2
The processing shown in FIG. 2 is performed based on the dot count number S _TD from 1 and the humidity shown in FIG.
The toner replenishment amount is corrected according to the humidity based on the relationship of the toner adhesion amount. Therefore, in addition to the correction result obtained by the processing shown in FIG. 2, the reference concentration obtained from the relationship shown in FIG.
A signal (S) for correcting the toner replenishment amount based on the correction result is corrected so that the density at 0% RH is obtained.
_OU ) is output to the image forming apparatus control circuit 11. In this embodiment, when 20 ° C. 60% RH is set as the condition for obtaining the reference density, and when 20 ° C. 30% RH, the toner replenishment amount corrected by the process shown in FIG. %, And at 20 ° C. and 90% RH, 3.5% of the toner replenishment amount corrected by the process shown in FIG.
It is designed to lose weight. According to the present embodiment, as a result of correcting the toner replenishment amount under various humidity environments with respect to the reference humidity, the ID variation value of the image based on the Macbeth value decreases from 0.17 to 0.08, and the background stain also occurs. It was constant and never changed.

It is also possible to input the output signal from the humidity sensor 70 to the correction circuit 20 via the image forming apparatus control circuit 11. In this case, as shown in FIG. 15, a signal input / output line is connected between the image forming apparatus control circuit 11 and the correction circuit 20 to output the output signal (V _HU ) from the humidity sensor 70 to the correction circuit 20. In the case shown in FIG. 14, by inputting to the image forming apparatus control device 11 as a feedback signal (S _OU ) the result obtained by performing the same correction as that shown in FIG. 14 as the input signal (S _IN ). Similar results are obtained. According to this embodiment, a stable image density can always be maintained regardless of changes in humidity, so that stable image quality can be obtained without causing excessive toner supply, insufficient toner supply, or background stain. Note that FIG.
Temperature sensor 60 shown in FIGS. 12, 14, and 15.
It is needless to say that the humidity sensor 70 may be the one used for other process control without special preparation.

The developer used in the developing device 4 is a virgin agent, that is, the state of the latest developer, the resistance value of the carrier decreases as the number of times of image formation increases, or the coating layer on the surface becomes thin so that the toner becomes toner. Is fixed, the charging function of the toner is deteriorated, and the developing ability, which means selective adhesion to the photoconductor, is deteriorated. Therefore, the amount of toner adhered to the electrostatic latent image, which is set to a constant surface potential on the photoconductor, is also reduced. Also,
The output value from the toner concentration detection sensor 10 may not match the actual concentration due to wear of the contact surface of the toner concentration detection sensor 10 with the developer or deterioration of the stirring members 3C, 3D (see FIG. 1) such as scrapers. is there.
As an example, when a paper passing test is performed on 10K (K = 1000) sheets of transfer material, when the surface potential is set to 500V, the toner adhesion amount per unit area is as shown in FIG. , It decreases as the number of passed sheets increases. Therefore, if the toner replenishment control is performed without considering the number of image formations on the assumption that the developer is the latest, the toner density will decrease depending on the number of image formations.

Therefore, it is necessary to maintain a constant toner density regardless of the increase in the number of sheets passed, which corresponds to the number of times of image formation.

FIG. 17 shows an embodiment in this case. This embodiment is based on the configuration of the embodiment shown in FIG. 1 and communicates with the image forming apparatus control circuit 11 and the correction circuit 20. A sheet number counting unit 80 is connected and configured. The sheet passing number counting unit 80 is adapted to store the total number of sheets passed up to the current stage when the sheet passing number information from the image forming apparatus control circuit 11 is input, and is newly added. It has a function of counting the number of sheets passed from, and outputs the number information signal (S _TR ) to the correction circuit 20. Correction circuit 20
Then, based on the number information signal from the sheet passing number counting unit 80, the toner replenishment amount is corrected according to the number of sheets-toner adhesion amount relationship shown in FIG. In this case, the correction is performed in such a direction as to obtain the toner adhesion amount when the first image formation is performed using the latest developer. Therefore, the replenishment amount based on the number information signal (S _TR ) is corrected with respect to the toner replenishment amount based on the toner concentration detection voltage (V _TC ) input from the toner concentration detection sensor 10 to the correction circuit 20, The correction result is the image forming apparatus control circuit 11
To the output signal (S _OU ).

According to the Macbeth value after passing 10K (K = 1000) sheets of A4 size transfer material when the longitudinal direction is set to the sheet passing direction using the configuration shown in FIG. As a result of observing the ID variation of the image, it was confirmed that the decrease in ID was decreased from 0.11 before correction to 0.05. In this embodiment, not only the number of sheets passed,
It is also possible to capture the size of the transfer material to be passed and the direction of passing the sheet as information for correction in the correction circuit.

As a method of judging that the developer is the latest one, there is a method such as a reset process of the number of passed sheets after replacing the developer or an automatic recognition of the developer replacement in the apparatus itself. Used. Further, among the above-described deterioration with time, the deterioration of the developer itself and the deterioration of the toner concentration detection sensor 10 of the developing device with time are separated, and each information is individually taken into the correction circuit 20 to set the correction amount. You may do it. As the sheet passing number counting unit 80 used in the above embodiment, an existing one can be used.

Another example of the decrease in the toner adhesion amount with the passage of time is the drive time of the main motor used for driving the various operation members such as the photosensitive drum 1 in addition to the above-mentioned example. The inventor pays attention to this point,
When the relationship between the drive time of the main motor and the toner adhesion amount was investigated, the results shown in FIG. 18 were obtained. FIG. 18 shows the amount of adhered toner per unit area on the photoconductor with respect to the drive time of the main motor when the surface potential is set to 500V. As is clear from FIG. 18, as the driving time of the main motor becomes longer, the toner adhesion amount decreases.

Therefore, it is necessary to maintain a constant toner density regardless of the increase in the drive time of the main motor.

FIG. 19 shows an embodiment in this case. This embodiment is based on the configuration of the embodiment shown in FIG. 1 and has a main circuit for the image forming apparatus control circuit 11 and the correction circuit 20. A motor drive time counting unit 90 is connected and configured. Main motor drive time counting section 90
Is a function of inputting and storing the total drive time up to the present stage from the image forming apparatus control circuit 11 and counting the drive time corresponding to the number of image forming times newly input from the image forming apparatus control circuit 11. And outputs the drive time information signal (S _™ ) to the correction circuit 20. In the correction circuit 20, based on the drive time information signal from the main motor drive time counting section 90,
From the relationship between the driving time and the toner adhesion amount shown in (4), the toner replenishment amount is corrected according to the driving time. In this case, the correction is performed in such a direction as to obtain the toner adhesion amount when the first image formation is performed using the latest developer. Therefore, the replenishment amount based on the drive time information signal (S _TM ) is corrected with respect to the toner replenishment amount based on the toner concentration detection voltage (V _TC ) input from the toner concentration detection sensor 10 to the correction circuit 20. The correction result is used as an output signal (S _OU ) to the image forming apparatus control circuit 11.

The inventor of the present invention changes the ID of an image depending on the Macbeth value after passing a transfer material of A4 size for 80 hours when the longitudinal direction is set in the sheet passing direction using the configuration shown in FIG. As a result, it was confirmed that the decrease in ID decreased from 0.10 before correction to 0.04.
Regarding the counting of driving time, if the stirring member in the developing device is stopped when a non-image is formed by using a clutch, etc., one that counts the driving time when the developing device is in operation However, the accuracy is expected to improve. Further, as the driving time counting unit 90, it is possible to use an existing counter or the like provided in the device.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the gist of the present invention. For example, the respective embodiments can be combined instead of being used alone. In this case, more accurate correction can be made by increasing the information regarding correction of toner replenishment. Further, since the reference voltage, the number of writing dots, the writing time, etc. used in the embodiment are peculiar to the device, it goes without saying that the characteristics of the device should be taken into consideration when carrying out.

[0077]

As described above, according to the first and second aspects.
According to the invention described, in the directions opposite to each other in the horizontal direction
The stirring members are arranged side by side so that the developer can be transferred.
One of the screws longer than the other
Feeding out the toner replenishment feeding member to the lengthened part
Is equipped with a structure that transfers the toner that is retained toward the other end in the axial direction.
The toner concentration in the developer is made constant for various developing devices.
The toner according to the change in the toner concentration in the developer
When replenishing the
Toner replenishment amount and correct the toner replenishment
The developer consumed in the driving state of the output member and the developing area
Was replenished in the developer when it reached the development area again
Toner replenishment start and end of toner replenishment
Since the end timing is set, the developer reaching the development area
The newly supplied toner is included in the
Emitted when the toner that is newly supplied in the area is not included.
The resulting uneven image density can be prevented .

According to the invention of claim 3, the start of development
Toner consumption tends to decrease at the end and at the end.
By reducing the amount of toner replenishment,
The toner concentration is kept constant by not replenishing the toner
Can be realized .

[0079]

[0080]

[0081]

[0082]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a basic system configuration of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a flowchart for explaining density correction performed by the image forming apparatus shown in FIG.

3 is a cross-sectional view showing a configuration of a main part of the image forming apparatus shown in FIG.

FIG. 4 is a timing chart for explaining a replenishment timing executed in the main part shown in FIG.

5 is a diagram for explaining the system configuration of a partial modification of the image forming apparatus shown in FIG.

6 is a flow chart for explaining density correction executed in the image forming apparatus shown in FIG.

FIG. 7 is a diagram for explaining a comparison between an image density obtained by the image forming apparatus shown in FIGS. 1 and 5 and an image density obtained by a conventional apparatus.

FIG. 8 is a sectional view showing a main part of an image forming apparatus according to an embodiment of the invention described in claim 2.

9 is a timing chart for explaining a replenishment timing executed in the main part shown in FIG.

FIG. 10 is a diagram for explaining the relationship between temperature and toner adhesion amount.

11 is a diagram showing a configuration of a main part of the image forming apparatus based on the relationship shown in FIG.

12 is a diagram showing a modification of the configuration of the main part shown in FIG.

FIG. 13 is a diagram for explaining the relationship between humidity and the amount of adhered toner.

FIG. 14 is a diagram showing a main part of the image forming apparatus based on the relationship shown in FIG.

15 is a diagram showing a modified example of the configuration of the main part shown in FIG.

FIG. 16 is a diagram for explaining the relationship between the number of sheets of paper passing corresponding to the number of times of image formation and the toner adhesion amount.

FIG. 17 is a diagram showing a main part of the image forming apparatus based on the relationship shown in FIG.

FIG. 18 is a diagram for explaining the relationship between the drive time of the main motor and the toner adhesion amount.

19 is a diagram showing a main part of the image forming apparatus based on the relationship shown in FIG.

FIG. 20 is a diagram illustrating a conventional example of an image forming apparatus having a configuration for replenishing toner.

21 is a cross-sectional view showing a main part of a developing device in the image forming apparatus shown in FIG.

22 is a perspective view of a main part shown in FIG. 21. FIG.

FIG. 23 is a cross-sectional view showing the internal structure of the main part shown in FIG. 21.

24 is a flowchart for explaining an image control procedure in the image forming apparatus shown in FIG.

[Explanation of symbols]

1 Photosensitive drum, which is one of the image bearing members 3 Writing scanning device 3A semiconductor laser 10 Toner density detection sensor 11 Toner density control image forming apparatus control circuit 20 Correction circuit 21 Writing dot counting section 22 Writing time counting section 60 temperature sensor 70 Humidity sensor 80 Paper passing count section 90 Main motor drive time counting section

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-116973 (JP, A) JP 4-320285 (JP, A) JP 52-139434 (JP, A) JP 58- 93080 (JP, A) JP-A-4-336571 (JP, A) JP-A-6-282166 (JP, A) JP-A-50-26550 (JP, A) Actual development Sho-53-139848 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 112 G03G 15/08 115 G03G 15/08 507

Claims (3)

(57) [Claims] 1. An image bearing member, and an electrostatic latent image formed on the image bearing member by irradiating and projecting scanning light is subjected to visible image processing by a two-component developer comprising a toner and a carrier. transfer means, to detect the toner concentration in the developer, the images forming apparatus having based on the detection result of the toner replenishing means for performing the toner replenishment control, the developer in opposite directions to each other in the horizontal direction I can do it
Of the screws as stirrers that are arranged side by side
One is made longer than the other and the
-Axial direction of toner delivered from the replenishment delivery member
A developing device having a configuration of moving toward the other end, and means for detecting a latent image writing area ratio by means for irradiating or projecting scanning light for forming the electrostatic latent image on the image carrier, Toner concentration in the developer and the latent image writing area
The respective rates are input, and the toner replenishing feeding member is provided.
And an image forming apparatus control circuit for controlling the operation of the developer.
The latent image is written when replenishing the toner according to the change in
Correct the toner replenishment amount according to the included area ratio
The drive status and current status of the toner replenishment feeding member.
When the developer consumed in the image area reaches the development area again
Make sure that the developer contains replenished toner
An image forming apparatus characterized in that the start and end timings of toner replenishment are set. 2. The image forming apparatus according to claim 1, wherein the toner supplement implemented in the image forming apparatus control circuit is used.
Set the feed start and end timings using the screw
The toner was consumed in the development area by moving along the axial direction of
Axial direction of the screw in which the developer lengthens the above axial direction
In the opposite direction,
Make sure to match the time to reach the position where replenishment is done
An image forming apparatus characterized by being performed . 3. An image forming apparatus according to claim 1, wherein the toner is fed from the toner replenishing feeding member.
Is a fixed amount during the above start and end timings.
Alternatively, the image forming apparatus is characterized by being changed at the start and the end .