JP2002169443A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which does not generate fogging, character dispersion and lowering of image density on an image obtained by mixing fresh toner and recycling toner. SOLUTION: The image forming device is provided with a photoreceptor, an electrifying device, an exposure optical system as an image exposure means, a developing device which performs image development with toner, a transfer device, and a cleaning device. The image forming device is further provided with a recycling toner transport device for reusing non-transferred toner as recycling toner by returning the non-transferred toner recovered with the cleaning device to a temporary storage tank of toner provided between the above developing device or this developing device and a fresh toner replenishing device. A toner ratio control device is provided for controlling the ratio of the quantity of recycling toner in the developing device or the temporary storage tank of toner and the quantity of fresh toner supplied from a fresh toner replenishing device.

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 such as a copying machine or a printer which uses a non-magnetic toner and has a mechanism for reusing recycled toner.

[0002]

2. Description of the Related Art In an image forming apparatus in which untransferred toner collected by a cleaning device is reused as recycled toner, the recycled toner is returned directly to a developing device or a toner temporary storage tank (buffer) mixed with fresh toner. Is returned to. At this time, since the amount of recycled toner returned is not particularly controlled, the ratio of the recycled toner in the developing device or the toner temporary storage tank increases when a copy in which the amount of recycled toner increases such as intermittent copying is frequently used. Here, the intermittent copying is a copying method in which a small number of copies, for example, about three or less, are intermittently taken. Recycled toners are generally stressed and therefore have changed physical properties, often impairing performance compared to fresh toners. Therefore, when the ratio of the recycled toner in the developing device or the toner temporary storage tank increases, “fog”, “character scattering”, “image density decrease”, and the like are likely to occur. These problems are further promoted by the environment inside or outside the image forming apparatus (for example, high temperature and high humidity environment),
It is likely to occur due to a decrease in the charge amount of the developer. In addition, since the toner produced by the polymerization method has a sharp physical property distribution, the property distribution of the recycled toner after the change in physical properties is greatly expanded, and the above-mentioned problem is more likely to occur.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and mainly uses a non-magnetic toner produced by a polymerization method and recovers an untransferred toner collected by a cleaning device. In the image forming apparatus that reuses the recycled toner as the recycled toner, the recycled toner is sent from the cleaning device to the developing device or the toner temporary storage tank so as to return to the image obtained by mixing the fresh toner and the recycled toner, It is an object of the present invention to provide an image forming apparatus in which problems such as "character scattering" and "image density reduction" do not occur.
In addition, the ratio of the fresh toner and the recycled toner according to the environmental conditions is adjusted so that, even in a high-humidity environment or a high-temperature and high-humidity environment, a stable high-quality image can be obtained as in a normal temperature and normal humidity state. It is an object of the present invention to provide an image forming apparatus capable of controlling the image forming apparatus to an appropriate value.

[0004]

This object is achieved by any of the following technical means (1) to (8).

(1) A photoreceptor as an image carrier, a charger for charging the photoreceptor, an exposure optical system as an image exposure means, a developing device for developing with toner, and a developed toner image are transferred to a transfer material. A recycle toner transport device for reusing the untransferred toner by returning the untransferred toner collected by the cleaning device to the developing device as recycled toner, the device being provided with at least a transfer device for performing the transfer and a cleaning device for cleaning the untransferred toner. And a toner ratio control device for controlling a ratio of the recycled toner amount and the fresh toner amount supplied from the fresh toner replenishing device in the developing device. Image forming device.

(2) A photoreceptor as an image carrier, a charger for charging the photoreceptor, an exposure optical system as an image exposure means, a developing device for developing with toner, and transferring the developed toner image to a transfer material And a cleaning device for cleaning the untransferred toner. The untransferred toner collected by the cleaning device is used as a recycled toner in a temporary toner storage tank provided between the fresh toner replenishing device and the developing device. An image forming apparatus provided with a recycled toner conveying device that reuses the untransferred toner by returning the untransferred toner, wherein the amount of the recycled toner and the fresh toner supplied from the fresh toner replenishing device in the toner temporary storage tank are provided. An image forming apparatus provided with a toner ratio control device for controlling a ratio to an amount.

(3) The toner ratio control device includes a recycled toner supply amount detecting device for detecting an amount of the recycled toner supplied to the developing device or the toner temporary storage tank, and a fresh toner for the developing device or the toner. A fresh toner replenishing amount detecting device for detecting an amount supplied to the temporary storage tank, wherein the recycle toner conveying device and the fresh toner replenishing device are operated based on a replenishing amount signal from each of the detecting devices. The image forming apparatus according to (1) or (2).

(4) A temporary storage tank for recycled toner is provided adjacent to the cleaning device from which the recycled toner is recovered, and the developing device or the temporary storage tank for toner is supplied from a supply port of the temporary storage tank for recycled toner. (1) to (3), wherein the amount of the recycled toner is controlled by rotating the transport screw connected to the supply port while the supply port is filled with the recycled toner. The image forming apparatus according to claim 1.

(5) There is provided an environment detecting means for detecting the temperature and humidity of the environment inside or outside the image forming apparatus, and replenishing the developing device or the toner temporary storage tank with the output of the temperature and humidity detection by the environment detecting means. (1) to (4) are performed to increase or decrease the amount of the recycled toner to be performed.
(4) The image forming apparatus according to any one of the above (4).

(6) The image forming apparatus according to any one of (1) to (5), wherein the toner is a non-magnetic toner and has a volume average particle diameter of 9 μm or less.

(7) Shape factor SF of the non-magnetic toner
-1 is 100 to 140, shape factor SF-2 is 100 to 1
20. The image forming apparatus according to item (6), wherein

(8) The image forming apparatus according to (6) or (7), wherein the non-magnetic toner is manufactured by a polymerization method.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of an image forming apparatus to which a transfer / conveying belt device of the present invention is applied is shown in FIG.
Will be described with reference to a schematic configuration diagram of FIG.

An image forming apparatus 1 shown in FIG. 1 is an image forming apparatus of a digital system, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer material conveying unit D as a transfer material conveying unit. It is configured.

An automatic document feeder for automatically conveying a document is provided above the image reading section A.
The original placed on the original 1 is moved by the original transport roller 12 to the original 1.
The sheets are separated and conveyed, and the image is read at the reading position 13a. The document for which reading of the document has been completed is discharged onto the document discharge tray 14 by the document conveying roller 12.

On the other hand, the image of the document placed on the platen glass 13 is read in the form of a V-shape by a reading operation at a speed v of a first mirror unit 15 comprising an illumination lamp and a first mirror constituting a scanning optical system. Reading is performed by moving the second mirror unit 16 including the second mirror and the third mirror located at the speed v / 2 in the same direction.

The read image is formed on a light receiving surface of an image sensor CCD as a line sensor through a projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (brightness signal), and then A
After performing / D conversion and performing processing such as density conversion and filter processing in the image processing unit B, the image data is temporarily stored in the memory.

In the image forming section C, as an image forming unit, a drum-shaped photosensitive member 21 serving as an image carrier, a charger 22 for charging the photosensitive member 21 on the outer periphery thereof, and a developing device 2
3. A transfer / conveying belt device 45 as a transfer means, a cleaning device 26 for the photoreceptor 21, and a PCL (precharge lamp) 27 as a light discharging means are arranged in the order of operation. The photoconductor 21 is formed by applying a photoconductive compound on a drum substrate, and is formed of, for example, an organic photoconductor (OP).
C) is preferably used and is driven and rotated clockwise as shown.

After the rotating photoreceptor 21 is uniformly charged by the charger 22, image exposure based on the image signal called from the memory of the image processing unit B is performed by the exposure optical system 30 as image exposure means. Done. An exposure optical system 30 serving as an image exposure means serving as a writing means uses a laser diode (not shown) as a light emission light source, passes through a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and the optical path is bent by a reflection mirror 32 to perform main scanning. In this case, image exposure is performed on the photoconductor 21 at the position Ao, and a latent image is formed by rotation (sub-scan) of the photoconductor 21. In one example of the present embodiment, a character portion is exposed to form a latent image.

The latent image on the photoreceptor 21 is subjected to reversal development by the developing device 23, and a visible toner image is formed on the surface of the photoreceptor 21. In the transfer material transport section D, paper feed units 41 (A) and 41 serving as transfer material storage means in which transfer materials P of different sizes are stored below the image forming unit.
(B) and 41 (C) are provided, and a manual paper feed unit 42 for performing manual paper feed is provided on the side, and a transfer material P selected from any of them is supplied to a guide roller 43.
The transfer material P is fed along the conveyance path 40, and the transfer material P is temporarily stopped by a pair of registration rollers 44 for correcting the inclination and deviation of the fed transfer material P, and then re-fed, and 40, the pre-transfer roller 43a, the paper feed path 46 and the entrance guide plate 47 guide the toner image on the photoconductor 21 to the transfer pole 24 and the separation pole 25 at the transfer position Bo.
Transfer transfer belt 45 of the transfer transfer belt device 45
The transfer material P is transferred to the transfer material P while being placed and transported on the transfer member 4, and is separated from the surface of the photoconductor 21.
To the fixing device 50.

The fixing device 50 has a fixing roller 51 and a pressure roller 52. By passing the transfer material P between the fixing roller 51 and the pressure roller 52, the toner is heated and pressurized. Weld. The transfer material P on which the toner image has been fixed is discharged onto the discharge tray 64.

The above is a description of a state in which an image is formed on one side of the transfer material. The image forming apparatus 1 of the present embodiment performs reverse conveyance before discharging the transfer material P, and An image is formed on the back side and double-sided transfer can be performed. However, since the double-sided transfer is not directly related to the present invention, the description thereof is omitted.

As shown in the front view of FIG. 2 and the perspective view of FIG. 4, the toner scraped off by the cleaning blade 26B provided downstream of the cleaning device 26 near the guide roller 26A is removed. The toner is collected and transported by the transport screw 26D, temporarily stored in the recycled toner temporary storage tank 26K, and returned to the developing device 23 for reuse. In this way, the amount of waste toner is drastically reduced, thereby preventing the occurrence of environmental problems due to contamination caused by improper processing of the waste toner, and improving the economic effect by reusing the toner.

More specifically, a guide roller 26A is provided in contact with the photosensitive member 21, and a cleaning blade 26B made of urethane rubber is provided on the photosensitive member 21 as a cleaning means provided on the downstream side near the guide roller 26A in a counter manner. The toner scraped off from the photoreceptor 21 is guided by the guide roller 26A while the conveying screw 26D
Is collected and stored in the recycled toner temporary storage tank 26K. The transport screw 485 provided inside a transport pipe (resin pipe) 484 as a transport path of the recycled toner transport device 480 supplies one end of the toner collected in the recycled toner temporary storage tank 26K to the stepping motor 26M. And the other end is rotatably supported by the bearing pin 23P1 of the support block 23P in the developing unit 23, so that the development is performed from the supply port 26G of the recycle toner temporary storage tank 26K. After being fed into the developing device 23 through the supply port 23G of the device 23 and mixed with the new toner conveyed from the fresh toner supply device 23A through the supply port 23AG, the developing device 23
The toner is supplied to the latent image on the photoreceptor 21 while being adjusted to an appropriate toner density (with respect to the carrier) in accordance with the control by the toner density sensor 23S in FIG.

In the front view of FIG. 3, a temporary toner storage tank 23K is connected between the fresh toner replenishing device 23A and the developing device 23, and the toner from the fresh toner replenishing device 23A is supplied to a supply port 23AG. The recycled toner that has passed through and is collected in the toner temporary storage tank 23K and transported by the transport screw 485 provided inside the transport pipe (resin pipe) 484 is also collected through the supply port 23G, mixed, and then supplied. The developer is supplied to the developing device 23 through the opening 23KG, and is uniformly stirred.
3B, the latent image formed on the photoconductor is developed.

The supply amount of fresh toner is controlled by the gate roller 23 provided in the fresh toner replenishing device 23A.
The rotation amount of Q is detected, and the supply amount of the recycled toner is detected by the rotation amount of the transport screw 485. However, in order for the supply amount of the recycled toner to be correctly detected based on the rotation amount of the transport screw 485, the recycled toner temporary storage tank 26
It is necessary that the K supply port 26G is filled so that at least the inside of the recycled toner is completely closed and filled. For this purpose, as shown in a partial front sectional view of FIG. 5, a level detector 2 of a recycled toner using, for example, a piezo element is provided at a position above the supply port 26G.
6 V is installed, and the drive is controlled so that the supply port 26G is confirmed to be filled with the recycled toner.

In this way, as shown in the circuit diagram of FIG.
A recycle toner supply amount detecting device 82 for detecting the rotation amount of the conveying screw 485 operating based on the V toner level satisfaction signal and a fresh toner supply amount detection device 83 for detecting the rotation amount of the gate roller 23Q. Upon receiving the detection signal, the recycled toner conveying device 48
The amount of rotation of the stepping motor 26M directly connected to the conveying screw 485 of the No. 0 via the connecting shaft 26MP and the amount of rotation of the stepping motor 23M directly connected to the gate roller 23Q of the fresh toner replenishing device 23A are determined so that a mixing ratio in a predetermined range can be obtained. Controlled.

As described above, the toner consumption rate is improved by about 20% as compared with the case where the toner is not recycled. In addition, the waste toner has almost disappeared, and the operation of receiving the waste toner and processing the industrial waste has been eased.

Next, the control operation of the image forming apparatus 1 in the case where environmental conditions such as temperature and humidity fluctuate will be described with reference to the flowcharts of FIGS. 7 and 8. (1) The copy operation is started in SP1,
When it is detected in SP2 that the inside or outside of the image forming apparatus is in a high-humidity environment or a high-temperature and high-humidity environment, FIG.
In the case of performing the control shown in (1), the process proceeds to the toner transport stop mode of SP3, and the recycled toner transport of SP4 is stopped.
That is, the supply of the recycled toner from the recycle toner temporary storage tank 26K to the developing device 23 or the toner temporary storage tank 23K is stopped, thereby completing the copying of SP12.

As shown in FIG. 8, when the amount of recycled toner is controlled without stopping, the ratio of the recycled toner in the developing device 23 or the temporary toner storage tank 23K is determined in a high humidity environment or a high temperature and high humidity environment. During detection, the upper limit 50%, which is the condition of (3) described below, is reduced to 20%, for example.
Is controlled. In this case, the flow proceeds to the recycled toner conveyance reduction mode of SP3a, and it is detected in SP7a whether the recycled toner has filled the supply port 26G of the recycled toner temporary storage tank 26K. 20 recycled toner
%, It is checked whether it is less than 20%, and if it is less than 20%, the process proceeds to SP10a, the transport of the recycled toner is carried out at that rate, and the copying is repeated as necessary in SP11a. However, during this time, the recycled toner is supplied to the supply port 2 of the recycled toner temporary storage tank 26K at SP7a.
When it is detected that 6G is not filled,
If the recycled toner does not become less than 20% in P9a, the process returns to SP8a to temporarily stop the transport of the recycled toner, and returns to SP7a to return to SP7a to SP7a to SP11a.
repeat. When the necessary copy is completed, the process proceeds to SP12, and the copy operation is completed. (2) In SP5, when the inside or outside of the image forming apparatus detects an environmental change (for example, a change from a high humidity environment to a normal humidity environment), a fixed copy number (for example, 200 copies)
After, or after a certain time, the developing device 23 or the toner temporary storage tank 23K from the recycled toner temporary storage tank 26K
In the flowchart of FIG. 7, the recycle of SP6 is performed so that the supply of the recycled toner to the toner is restarted in the flowchart of FIG. The toner transport is switched to the normal transport mode. (3) In SP9, the ratio of the recycled toner and the fresh toner in the developing device 23 or the toner temporary storage tank 23K is set to 1 in the total toner amount in the developing device 23 or the toner temporary storage tank 23K regardless of the environment detection. Time,
It is a standard that the ratio of the recycled toner is 0.5 or less. If the condition is satisfied, the process proceeds to SP10. If the ratio is exceeded, the process returns to SP8, and the transport of the recycled toner is temporarily stopped. (4) In SP7, the recycled toner temporary storage tank 26K has a configuration as shown in FIG. 5, stores the recycled toner dropped from above, and supplies the recycled toner to the developing device 23 or the toner temporary storage tank 23K. 26
After G is completely filled, conveyance of the recycled toner to the developing device 23 or the temporary toner storage tank 23K is started. Thereby, the recycled toner transport device 480 transported to the developing device 23 or the temporary toner storage tank 23K.
The transported amount of the recycled toner in the container can always be controlled to a fixed ratio or less with respect to the transported amount of the fresh toner. Whether or not the supply port is buried is detected using, for example, the above-described piezo element or optical sensor. If the filling is not detected, the conveyance of the recycled toner is temporarily stopped at SP8. (5) The amounts of the recycled toner and the fresh toner supplied to the developing device 23 or the toner temporary storage tank 23K are detected based on the operation states of the recycled toner transport device 480 and the fresh toner replenishing device 23A.

More specifically, it is detected by the rotation time and rotation speed of the transport screw 485 and the gate roller 23Q, or the operation time and operation speed of the driving device (motor 26M, 23M, etc.) of each device. (6) Recycled toner has a large change in physical properties as compared with fresh toner since small particle size toner is vulnerable to stress.
In particular, the present technology is effective for toner having a volume average particle diameter of 9 μm or less. Although an effect is obtained even when the thickness is 9 μm or more, the effect is smaller than the above range. (7) Since the physical property distribution of the polymerized toner is sharp, the property change of the recycled toner is larger than that of the fresh toner.
In particular, the shape factor SF-1 is 100 to 140, and the shape factor SF
The present technology is particularly effective for toner having a value of -2 from 100 to 120. Other shape factors are effective, but less effective than the above range.

Here, the shape factors SF-1 and SF-2 will be described as follows. SF-1 indicates the degree of sphere, SF-2 indicates the degree of unevenness,
It is given by the following equation.

SF-1 = {(Lmax) ² / A} × (π
/ 4) × 100 SF-2 = {(Laound) ² / A} × (1/4
π) × 100 Lmax; maximum diameter, Laround; perimeter, A;
Toner projection area

[0034]

Example 1 Example 1 is performed under the following conditions unless otherwise specified.

Image forming system: Electrophotographic (Carlson process) dry two-component developing system Photoreceptor: negatively charged OPC, φ80 mm, rotational linear velocity 280 mm / sec, charging potential -750 V Band electrode: scorotron, charging current value -800 μm
A, grid voltage -730V Exposure optical system: laser scanning method, 600 dpi (d
pi is a unit of resolving power indicating the number of points that can be identified within a length of 25.4 mm), laser power 300 μW, beam diameter 50 μm in the main scanning direction, 80 μm in the sub-scanning direction Developer: carrier particle diameter 60 μm, toner particle diameter 5
μm (produced by emulsion polymerization method), shape factor SF-1 is 1
20, shape factor SF-2 is 110 Developing device: bias is -600 V, sleeve diameter φ
40 mm, linear rotation speed 560 mm / sec Transfer separation electrode: Electrostatic transfer / electrostatic separation method Cleaning: Urethane rubber blade counter method Environmental detection: Detection is performed by a humidity sensor arranged near the developing unit inside the image forming apparatus.

Recycled toner ratio control: When high humidity is detected, the conveyance of the recycled toner from the recycled toner temporary storage tank is stopped.

Only the recycled toner temporary storage tank 26K is provided (recycled toner is directly returned to the developing device), and the recycled toner temporary storage tank 26K and the toner temporary storage tank 23K are provided.
(Buffer) A running test is performed on a three-level machine with both buffers and no temporary storage tank while changing the use environment.

The image forming apparatus having only the recycle toner temporary storage tank 26K and the image forming apparatus also having the toner temporary storage tank 23K have all of the above conditions, and the set values of the preferable conditions are as follows.

(Setting Values of Preferred Conditions) 1) When it is detected that the environment of high humidity (65% RH or more) has changed to become an environment of normal humidity (less than 65% RH and around 50% RH). After 200 copies from the detection of the environmental change, supply of the recycled toner is started from the recycled toner temporary storage tank 26K. 2) Supply port 26G of temporary storage tank 26K for recycled toner
Of the supply port 26G as a means for detecting the possibility of supply by detecting the filling of the toner
For example, the above-described piezo element is disposed above the piezo element, and detection is performed based on a change in the output of the piezo element when the recycled toner reaches the piezo element. 3) The detection of the supply amounts of the recycled toner and the fresh toner to the developing device 23 is performed by the recycled toner conveying device 480.
And the toner replenishing device 23A are provided with stepping motors 23M and 26M as drive sources, respectively, so that the amount of recycled toner and the amount of fresh toner supplied to the developing device 23 can be detected based on the operation time.

(Running test conditions) (A) An operation equivalent to 150,000 copies of A4 size continuous copy is performed, and (B) the use environment of the machine is changed every 10,000 copies.
The order is as follows.

(1) Normal temperature and normal humidity (20 ° C./50% RH) (2) Low temperature and low humidity (10 ° C./20% RH) (3) High temperature and high humidity (30 ° C./80% RH) (1) (3) was repeated.

(Result) Recycled toner temporary storage tank 26
In the image forming apparatus having only K and the image forming apparatus also including the fresh toner temporary storage tank 23K, no image defects (fogging, character scattering, image density reduction, etc.) occurred during the entire running test. The recycled toner and the fresh developer in the developing device 23 are periodically measured by using the recycled toner in the recycled toner conveying device 480, the developing toner developed on the photoconductor 21, and the fresh toner in the fresh toner replenishing device 23A. Assuming that the total amount of toner in the developing device is 1, as shown in the graph of FIG. 9, the ratio of the recycled toner is 0.12 in the image forming apparatus having only the recycled toner temporary storage tank 26K.
-0.46, the value was between 0.14 and 0.44 in the image forming apparatus having both the recycled toner temporary storage tank 26K and the toner temporary storage tank 23K (buffer).

On the other hand, in the image forming apparatus 1 without the temporary storage tanks 23K and 26K, "fogging" occurs during the high-temperature and high-humidity environment from 20,000 copies, and even after the normal temperature and normal humidity environment starts from 30,000 copies. About 150 copies of "fogging" occurred and then disappeared. Also, "character scattering" began to be noticeable in a high-temperature, high-humidity environment of 80,000 to 90,000 copies. At a high temperature and a high humidity of 140,000 to 150,000 copies, "image density decrease" occurred, and the image was remarkably deteriorated. The ratio between the recycled toner and the fresh toner changed from 0.41 to 0.69 when the total amount of toner in the developing device was 1.

The measurement of the ratio of the recycled toner will be described later. Example 2 Unless otherwise specified, Example 2 was performed under the same conditions as Example 1.

That is, the recycled toner ratio control reduces the transport of recycled toner from the recycled toner temporary storage tank 26K when high humidity is detected, and performs the same running test as in the first embodiment. The set value at that time is the same as the set value of the following preferable condition.

(Setting Values of Preferred Conditions) 1) When high humidity is detected, the amount of recycled toner in the developing device 23 is set to 0.2 or less of the total amount of toner. 2) High humidity (65% RH or more) environment changes to normal humidity (6% or more).
When the environment is detected (less than 5% RH and around 50% RH)
After 200 copies from the environmental change detection, the supply amount of the recycled toner from the recycled toner temporary storage tank 26K is returned to the normal humidity level. Other (running test conditions)
Was the same as in (Example 1).

(Result) Recycled toner temporary storage tank 26
In the image forming apparatus 1 with K, no image defects (fogging, character scattering, image density reduction, etc.) occurred during the entire running test. The recycled toner and the fresh developer in the developing device 23 are periodically measured by using the recycled toner in the recycled toner conveying device 480, the developing toner developed on the photoconductor 21, and the fresh toner in the fresh toner replenishing device 23A. The toner ratio is
As shown in the graph of FIG. 10, when the total amount of toner in the developing device 23 is 1, the recycled toner is 0.13 in the image forming apparatus 1 having only the recycled toner temporary storage tank 26K.
In the image forming apparatus 1 having both the recycled toner temporary storage tank 26K and the toner temporary storage tank 23K (buffer), the value fluctuated between 0.14 and 0.45.

On the other hand, a recycle toner temporary storage tank 26K
In the image forming apparatus 1 without the image, "fogging" occurs during the high-temperature and high-humidity environment from 20,000 copies, and "fogging" occurs about 150 copies after starting the normal temperature and normal humidity environment from 30,000 copies, and then disappears. did. Also, "character scattering" began to be noticeable in a high-temperature, high-humidity environment of 80,000 to 90,000 copies. 14
At a high temperature and a high humidity of 10,000 to 150,000 copies, "image density decrease" occurred, and the image was remarkably deteriorated. The ratio between the recycled toner and the fresh toner changed from 0.38 to 0.66 when the total amount of toner in the developing device 23 was 1.

(Supplementary Explanation on Measurement of Ratio of Fresh Toner and Recycled Toner) In a recycled toner, an external additive on the toner surface is more likely to be peeled off or buried than a fresh toner due to mechanical stress or the like.
Therefore, by measuring the amount of the external additive on the toner surface using an X-ray diffraction analyzer or the like, the difference between the amount of the external additive on the fresh toner and the amount of the external additive on the recycled toner surface can be measured. In this embodiment, attention is paid to Si (silica) in the external additive, and the ratio of fresh toner and recycled toner is measured by measuring the amount of Si on the surface of the developed toner developed on the photoreceptor 21 with fresh toner and recycled toner. Could be asked. The calculation formula is shown below.

Ratio of recycled toner in the developing device: a Since the ratio of fresh toner in the developing device is 1−a, (amount of developed toner Si) = (amount of recycled toner Si)
Amount) x a + (Si amount of fresh toner) x (1-a) =
(Amount of fresh toner Si) + ((Recycled toner S
The formula of (i amount)-(fresh toner Si amount)) × a holds, therefore, a = ((developing toner Si amount)-(fresh toner Si amount)) ÷ ((recycled toner Si amount)
− (Fresh toner Si amount)).

[0051]

According to the present invention, when a non-magnetic toner produced mainly by a polymerization method is used, an untransferred toner collected by a cleaning device is reused as a recycled toner to form an image with stable high image quality. The device can be used, and the recycled toner is sent from the cleaning device back to the developing device or the temporary toner storage tank, and the image obtained by mixing the fresh toner and the recycled toner is subjected to “fogging”, “character scattering”, “image As a result, an image forming apparatus free from such problems as "density reduction" was obtained. Furthermore, for example, in a high humidity environment or a high temperature and high humidity environment, the ratio of the fresh toner and the recycled toner is set to an appropriate value according to the environmental conditions so that a stable high-quality image can be obtained as in the normal temperature and normal humidity state. Thus, an image forming apparatus that can be controlled at a high speed was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus of the present invention.

FIG. 2 is a partial front view of an example in which recycled toner collected from a cleaning device in the image forming apparatus of the present invention is fed into fresh toner of a developing device.

FIG. 3 is a partial front view of an example in which recycled toner collected from a cleaning device in the image forming apparatus of the present invention is fed into fresh toner in a temporary toner storage tank.

FIG. 4 is a perspective view showing an arrangement of a cleaning device, a recycled toner conveying device, and a photoconductor in the image forming apparatus of the present invention.

FIG. 5 is a partial front cross-sectional view showing a level detector for detecting a state of recycled toner filling a supply port of a recycled toner temporary storage tank and a recycled toner conveying device.

FIG. 6 is a circuit diagram illustrating toner ratio control.

FIG. 7 is a flowchart illustrating switching between the normal mode of the recycled toner transport and the recycled toner transport stop mode in the present invention.

FIG. 8 is a flowchart illustrating switching between a normal mode of recycled toner transport and a reduced recycled toner transport mode in the present invention.

9 is a graph corresponding to the mode of FIG. 7 and showing a state in which the ratio of recycled toner to all toner during development changes according to the number of copies.

FIG. 10 is a graph showing a state in which the ratio of recycled toner to all toner during development changes in accordance with the number of copies, corresponding to the mode of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Photoreceptor 22 Charger 23 Developing device 23A Fresh toner replenishing device (Toner replenishing device) 23B Sleeve 23G, 23AG, 23KG, 26G Supply port 23K Toner temporary storage tank 23M, 26M Stepping motor 23P Support block 23P1 Bearing pin Reference Signs List 26 Cleaning device 26A Guide roller 26B Cleaning blade 26D, 485 Transport screw 26K Recycle toner temporary storage tank 26MP Connecting shaft 26V Level detector 30 Exposure optical system 45 Transfer transport belt device 50 Fixing device 81 Toner ratio control device 82 Recycled toner supply amount detection Device 83 Fresh toner supply amount detection device 480 Recycled toner transport device 484 Transport pipe (resin pipe)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/00 372 (72) Inventor Toru Yamaguchi 2970, Ishikawacho, Hachioji-shi, Tokyo Konica Corporation F-term ( Reference) 2H005 AA15 AB06 EA05 2H027 DA11 DA14 DA41 DD01 DD03 EA06 EC06 ED10 2H034 BF01 CA02 CA04 CB01 2H077 AA11 AA15 AA37 AC02 AC16 AD02 AD06 DA12 DA18 DA35 DA45 DA72 DB02 EA14

Claims (8)

[Claims] 1. A photoreceptor as an image carrier, a charger for charging the photoreceptor, an exposure optical system as an image exposure unit, a developing device for developing with toner, and transferring the developed toner image to a transfer material A recycle toner transport device that includes at least a transfer device and a cleaning device that cleans the untransferred toner, and that reuses the untransferred toner by returning the untransferred toner collected by the cleaning device to the developing device as recycled toner. An image forming apparatus comprising: a toner ratio control device that controls a ratio between the amount of recycled toner and the amount of fresh toner supplied from a fresh toner replenishing device in the developing device. Forming equipment. 2. A photoreceptor as an image carrier, a charger for charging the photoreceptor, an exposure optical system as image exposure means, a developing device for developing with toner, and transferring the developed toner image to a transfer material. At least a transfer device and a cleaning device for cleaning untransferred toner are provided, and the untransferred toner collected by the cleaning device is returned to a temporary toner storage tank provided between the fresh toner replenishing device and the developing device as recycled toner. An image forming apparatus provided with a recycled toner conveying device for reusing the untransferred toner, wherein the amount of recycled toner and the amount of fresh toner supplied from the fresh toner replenishing device in the temporary toner storage tank An image forming apparatus provided with a toner ratio control device for controlling the ratio of the toner image. 3. The toner ratio control device includes a recycled toner supply amount detection device that detects an amount of the recycled toner supplied to the developing device or the toner temporary storage tank, and a fresh toner that is supplied to the developing device or the toner temporary storage tank. A fresh toner replenishing amount detecting device for detecting an amount supplied to the storage tank, wherein the recycle toner conveying device and the fresh toner replenishing device are operated based on a replenishing amount signal from each of the detecting devices. Claim 1
Or the image forming apparatus according to 2. 4. A recycle toner temporary storage tank is provided adjacent to the cleaning device from which the recycle toner is collected, and replenished to the developing device or the toner temporary storage tank from a supply port of the recycle toner temporary storage tank. The amount of the recycled toner is controlled by rotating a transport screw connected to the supply port while the supply port is filled with the recycled toner, and controlling the rotation amount. Item 10. The image forming apparatus according to item 1. 5. An image forming apparatus comprising: an environment detecting unit for detecting a temperature and a humidity of an environment inside or outside the image forming apparatus; and an output of the temperature and humidity detection by the environment detecting unit is supplied to the developing device or the toner temporary storage tank. The image forming apparatus according to claim 1, wherein control is performed to increase or decrease the amount of the recycled toner. 6. The toner according to claim 1, wherein the toner is a non-magnetic toner and has a volume average particle diameter of 9 μm or less.
6. The image forming apparatus according to claim 5. 7. The image forming apparatus according to claim 6, wherein the non-magnetic toner has a shape factor SF-1 of 100 to 140 and a shape factor SF-2 of 100 to 120. 8. The image forming apparatus according to claim 6, wherein the non-magnetic toner is manufactured by a polymerization method.