JP3400620B2 - Electrophotographic recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a laser printer,
The present invention relates to an electrophotographic recording device such as a plain paper facsimile device and a copying machine, and more particularly to an electrophotographic recording device using a one-component toner.

[0002]

2. Description of the Related Art In a conventional electrophotographic recording device, a developing device for developing an electrostatic latent image formed on an electrophotographic photosensitive member such as a photosensitive drum with toner, and a device detachably attached to the main body of the device. And a toner cartridge for replenishing the toner in the toner storage portion of the developing device.

FIG. 8 is a block diagram showing an example of a conventional electrophotographic recording apparatus as described above. Reference numeral 1 denotes a toner cartridge in which a toner tank 2 stores a one-component magnetic toner (hereinafter, simply referred to as toner). Yes, toner cartridge 1
Is detachably attached to the illustrated attachment position. In this toner cartridge 1, 3 and 4 are agitators and magnetic rollers respectively rotatably supported in the toner tank 2 and connected to a drive mechanism (not shown), and 5 are toner supply ports opened in the toner tank 2. A plurality of toner supply ports 5 are provided in the longitudinal direction as shown in FIG.

Reference numeral 6 denotes a developing device. In this developing device 6, 7 is a case, 8 is a toner storage portion formed in the case 7, and 9 is a stirring member rotatably supported in the toner storage portion 8. A plate, 10 is a toner receiving opening opened in the case 7, 11 is a developing roller arranged next to the stirring plate 9 in the case 7, and 12
Is a doctor blade whose front end is brought close to the surface of the developing roller 11, and 13 is an intermediate roller in contact with the developing roller 11.

Reference numeral 14 is a photoconductor drum which is an electrophotographic photoconductor.
Reference numeral 15 is a transfer roller in contact with the photoconductor drum 14, 16 is a cleaning device in which a blade 16a is brought into contact with the surface of the photoconductor drum 14, and 17 is a charging device facing the photoconductor drum 14.

Next, the operation of the electrophotographic recording apparatus having the above structure will be briefly described. Photoconductor drum 14 that rotates in the direction of the arrow
Is charged by the charger 17 to a predetermined potential and then scanned by the laser light L emitted from an optical writer (not shown), so that an electrostatic latent image is formed on its image bearing surface. The developing device 6 rotates the stirring plate 9, the developing roller 11, and the intermediate roller 13 at the time of developing the electrostatic latent image, and applies a bias voltage to the intermediate roller 13 and the like. At this time, the agitating plate 9 agitates the toner in the toner storage portion 8, and the developing roller 11 adsorbs the toner agitated by the agitating plate 9. The toner adsorbed on the developing roller 11 is thinned by the doctor blade 12 and is triboelectrically charged to transfer and adhere to the intermediate roller 13. The toner transferred and adhered to the intermediate roller 13 is a photoconductor due to electrostatic force. The electrostatic latent image formed on the photosensitive drum 14 by being transferred and attached to the drum 14 is developed into a toner image. The toner image on the photoconductor drum 14 is transferred to the recording paper P by the transfer roller 15, and the toner remaining on the photoconductor drum 14 after the transfer is completed is removed and collected by the cleaning device 16.

On the other hand, the toner cartridge 1 replenishes the toner storage portion 8 with an amount of toner substantially equal to the amount consumed by the development so that the toner in the toner storage portion 8 is maintained at a predetermined amount in a steady state. . The toner cartridge 1 rotates the agitator 3 when replenishing the toner to the developing device 6, agitates the toner in the toner tank 2 by the agitator 3, and adsorbs the toner by the magnetic roller 4 that rotates in conjunction with the agitator 3. The toner attracted to the magnetic roller 4 is scraped off by the peeling member 18 provided at the downstream position of the toner supply port 5 as the magnetic roller 4 rotates.
The toner drops into the toner storage unit 8 through the toner supply port 5 and the toner receiving port 10.

[0008]

The toner used in the electrophotographic recording apparatus as described above usually contains additives for adjusting lubricity and controlling charging characteristics. Since this additive has a characteristic that it is less likely to be transferred and adhered to the photosensitive drum 14 as compared with toner particles that are a coloring component, a phenomenon that the concentration of the additive increases in the toner storage portion 8 as the number of development times increases. Occurs. As the concentration of the additive in the toner stored in the toner storage portion 8 increases, the amount of toner transferred per unit area from the intermediate roller 13 to the photosensitive drum 14 decreases, and the image density of the toner image decreases. That problem is likely to occur.

The description and drawings attached to the application of Japanese Patent Application No. 7-106516 filed by the applicant of the present application on April 28, 1995 show the construction of the developing device applied to the electrophotographic recording apparatus. As "a toner storage portion for accumulating a one-component toner to be attached to the electrostatic latent image of the electrophotographic photosensitive member, a stirring means for stirring the toner in the toner storage portion, and detachable with respect to the apparatus main body, Further, in a developing device having a toner cartridge for storing new toner therein and for supplying the new toner to the toner storage portion, a supply port for feeding the new toner inside and a new supply port for supplying the new toner to the toner cartridge. A transfer unit that transfers toner, a recovery port into which the toner pushed out by the stirring unit enters, and a transfer unit that moves the toner stored in the toner storage unit to a portion facing the recovery port. A developing unit provided with a feeding unit and a collecting unit that conveys the toner entering from the collecting port inside is described. By applying the developing unit to an electrophotographic recording apparatus, the number of times of development described above increases. It is described as an effect that the problem that the image density is reduced can be solved.

However, in the developing device described in the specification and drawings attached to the application of Japanese Patent Application No. 7-106516, the transfer means always moves the toner to the opposite portion of the recovery port in the toner storage portion at a constant speed. . For this reason, even when this developing device is applied to an electrophotographic recording device, the toner remaining in the toner tank becomes less than a certain amount and the toner supplied from the toner cartridge to the toner storage unit per unit time. When the amount of toner decreases, the amount of toner moved by the transfer means becomes larger than the amount of toner supplied from the supply port, so the amount of toner accumulated near the supply port decreases and the amount of toner accumulated near the recovery port decreases. Will increase. Further, in this developing device, the supply ports are arranged at both ends in the longitudinal direction of the toner cartridge, and the recovery port is arranged in the central portion in the longitudinal direction of the toner cartridge, and the longitudinal direction of the toner cartridge is in the main scanning direction with respect to the electrophotographic photosensitive member. It almost agrees with. As a result, the amount of toner transferred and attached to both ends of the photoconductor drum 14 in the main scanning direction is reduced in response to the decrease in the amount of toner accumulated near the supply port in the toner storage unit, and the toner is developed on the photoconductor drum 14. There is a problem that the image density of the formed toner image is reduced at both ends in the main scanning direction.

According to the present invention, it is possible to prevent the image density of the toner image developed on the photosensitive drum from becoming unstable due to the increase of the additive concentration in the toner storage portion or the non-uniformity of the toner accumulation amount. An object is to provide a photographic recording device.

[0012]

In order to solve the above problems, an electrophotographic recording apparatus according to claim 1 of the present invention transfers a one-component toner filled in a toner storage portion onto an electrophotographic photosensitive member. Developing means for developing an electrostatic latent image formed on the electrophotographic photosensitive member by a one-component toner, and a one-component toner detachably attached to the apparatus main body and housed in a toner tank. in electrophotographic recording apparatus having a toner cartridge for replenishing before Symbol toner accommodating portion, a one-component toner accommodated in said toner accommodating portion, conveyed to the central portion from both ends of the toner containing portion
Backflow conveying means provided in said toner accommodating portion, wherein
Toner supply ports are provided on both ends of the toner cartridge in the longitudinal direction.
Forming a toner recovery port at the center,
When the cartridge is detachably attached to the device body
The toner supply port and toner in the developing unit.
-Form an opening in the area facing the recovery port to supply the toner.
Transport the one-component toner to the supply port to
Drop one-component toner onto both ends of the toner storage section.
In addition, the toner is conveyed by the backflow toner conveying means.
-One-component toner transported near the collection port
Through the toner recovery port and into the toner tank.
And then merge with the one-component toner in the toner tank.
It provided a toner backflow means for the toner tank, that the transport speed of the one-component toner by the reverse flow conveying means, provided with a toner circulation control means for changing in correspondence with the amount of toner remaining in the toner tank Characterize.

Further, in the electrophotographic recording apparatus according to the present invention, the toner circulation control means conveys the backflow toner when the toner remaining amount in the toner tank becomes equal to or less than a preset near-end toner amount. It is characterized in that the means is stopped.

According to a third aspect of the present invention, the electrophotographic recording apparatus is formed on the electrophotographic photosensitive member by transferring and adhering the one-component toner filled in the toner storage portion onto the electrophotographic photosensitive member. a developing unit for developing the electrostatic latent image by the one-component toner, the toner cartridge for replenishing is detachably attached to the apparatus main body, and a one-component toner accommodated in the toner tank before Symbol toner storage portion In the electrophotographic recording apparatus having the
The one-component toner, the middle from both ends of the toner containing portion
The backflow toner conveying means for conveying the toner to the central portion is provided in the toner storing section.
Are installed inside the toner cartridge, and at both ends of the toner cartridge in the longitudinal direction.
Toner supply port is formed and toner recovery port is formed in the center
The toner cartridge can be attached to and detached from the main unit
The toner supply to the developing means when it is mounted properly.
Opening is formed in the part facing the supply port and toner recovery port
Then , the one-component toner is fed to the toner supply port side before
One component from the toner supply port to both ends of the toner storage unit
Drop the system toner, and
The toner was conveyed near the portion facing the toner recovery port by the step.
Pass the one-component toner through the toner recovery port and
-Reverse flow into the tank to create a one-component system in the toner tank
The toner backflow means for merging with the toner is provided in the toner tank.
The toner carrying capacity of the backflow toner carrying means provided inside
The, than near the opposing portion between the toner supply opening, wherein the kite is made larger at the opposite side of said toner collecting port.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Members corresponding to those shown in FIGS. 8 and 9 are designated by the same reference numerals,
The description is omitted. FIG. 1 is a side sectional view showing a configuration of a main part of an embodiment of the electrophotographic recording apparatus of the present invention, and FIG. 2 is a perspective view of a toner cartridge in the electrophotographic recording apparatus of the present embodiment. Reference numeral 20 denotes a toner cartridge that stores toner in the toner tank 21, and the toner cartridge 20 is removably mounted at the mounting position shown in the figure. In the toner cartridge 20, 22 is a toner tank
The blade 22 is supported within 21, and the blade 22 comes into contact with the surface of the magnetic roller 4 only at the axial center thereof. Reference numeral 23 denotes a peeling member that protrudes from the inner surface of the toner tank 21 toward the magnetic roller 4, and the pair of peeling members 23 have their front ends in close proximity to the surface of this roller only at both axial end portions of the magnetic roller 4. .

Further, 24 and 25 are toner tanks, respectively.
Reference numeral 21 denotes a toner collecting port and a toner supplying port which are opened below the magnetic roller 4, the toner collecting port 25 is opened at a position facing both axial ends of the magnetic roller 4, and the toner supplying port 24 is provided at the toner supplying port 24. A plurality of openings (three in FIG. 2) are opened at positions facing the central portion in the axial direction.

Reference numeral 30 denotes a developing device. In the developing device 30, 31 is a case, 32 is a plurality of toner circulation ports opened in the case 31, and the plurality of toner circulation ports 32 are the toner cartridge 20 at the mounting position. The toner recovery port 24 and the toner supply port 25 are opened at positions facing each other. 33 is a sponge arranged on the upper surface of the case 31.
Has a plurality of insertion holes communicating with the toner circulation port 32, and in a state where the toner cartridge 20 is mounted at the mounting position, the toner cartridge 20 is in close contact with the lower surface of the toner cartridge 20 and the toner circulation port 32 and the toner recovery port 24 or the toner supply port. Connect with mouth 25. Reference numeral 34 is a screw feeder which is provided on the outer periphery of the stirring plate 9 and functions as a back-flow toner conveying means. As shown in the perspective view of FIG. 3, the pair of screw feeders 34 are provided in a coil shape at both ends of the stirring plate 9, respectively. Thus, the winding direction is such that the toner in the vicinity of the position facing the toner supply port 25 is transported to the vicinity of the position facing the toner recovery port 24. Reference numeral 35 denotes a toner sensor which is supported at a position close to the bottom surface of the toner tank 21 when the toner cartridge 20 is mounted at the mounting position.

Next, the operation of the main part of the electrophotographic recording apparatus of this embodiment will be described. The developing device 30 is a photosensitive drum.
During development of the electrostatic latent image formed on 14, the stirring plate 9, the developing roller 11, and the intermediate roller 13 are rotated, and a predetermined bias voltage is applied to the intermediate roller 13 and the like. At this time, the agitating plate 9 agitates the toner in the toner storage portion 8, and the developing roller 11 adsorbs the toner agitated by the agitating plate 9. The toner attracted to the developing roller 11 is frictionally charged together when thinned transition adhering to the intermediate roller 13 by a doctor blade 12, toner transferred adheres to the intermediate roller 13, the electrostatic force The electrostatic latent image formed on the photosensitive drum 14 by being transferred and attached to the photosensitive drum 14 is developed into a toner image.

Here, in the screw feeder 34, as the stirring plate 9 rotates in the direction of arrow A, the toner storage portion 8
The toner in the vicinity of the position facing the toner supply port 25 is transported to the vicinity of the position facing the toner recovery port 24. The toner conveyed by the screw feeder 34 and accumulated near the position facing the toner recovery port 24 is agitated by the agitation plate 9, so that a part of the toner is circulated in the toner circulation port 32 and the sponge.
It flows back into the toner tank 21 through 33 and the toner recovery port 24, and is attracted to the magnetic roller 4. As the magnetic roller 4 rotates in the direction of arrow B, the toner attracted to the magnetic roller 4 is peeled off by the blade 22 having its tip in contact with the central portion of the magnetic roller 4 and falls to the bottom of the toner tank 21. The toner is deposited on the toner remaining in the toner tank 21, and then mixed by the agitator 3 so as to be uniform.

The agitator 3 mixes the residual toner in the toner tank 21 and the backflow toner from the developing device 30 and agitates the mixed toner. The agitated toner is attracted to the magnetic roller 4, and the toner attracted to both ends of the magnetic roller 4 is conveyed onto the toner supply port 25, is peeled by the peeling member 23, and falls into the toner storage unit 8.

In the electrophotographic recording apparatus of the present embodiment, the screw feeder 34 functioning as a backflow toner conveying means.
And the stirring plate 9, the magnetic roller 4 and the blade 22 which function as toner backflow means perform the above-mentioned operations, whereby the toner in the toner storage portion 8 and the toner in the toner tank 21 circulate and the toner tank The composition of the toner in 21 and the developing device 30 is made uniform, and the concentration of the additive in the toner in the toner storage portion 8 is suppressed.

FIG. 4 is a block diagram showing the arrangement of the control section in the electrophotographic recording apparatus of this embodiment. 51 is a CPU
(Central processing unit), 52 is a memory that stores control conditions for the device, 53 is an A / D converter that converts the detection signal from the toner sensor 35 from analog to digital, and 54 is the main motor 36 and the variable mechanism 37. It is a drive system control circuit for controlling. The main motor 36 is a drive source for rotating members such as the photosensitive drum 14 shown in FIG. 1, and the variable mechanism 37 is a drive system control circuit 54.
It is configured to switch the speed reduction ratio in accordance with the signal from the agitator plate 9 via the variable mechanism 37.
The rotational force from 36 is transmitted.

FIG. 5 is a characteristic diagram showing the relationship between the detection signal from the toner sensor of this embodiment and the remaining amount of toner in the toner tank. The sensor output, which is the detection signal output from the toner sensor 35, decreases as the remaining toner amount in the toner tank 21 decreases, but as is clear from FIG.
The output reduction rate changes drastically with a boundary around 50g. Here, W _L plotted on the horizontal axis is the toner lower limit amount at which the toner supply amount to the toner storage unit 8 per unit time sharply decreases when the remaining toner amount is less than this, or W _L
E is the near-end toner amount at which the toner supply amount to the toner storage unit 8 per unit time becomes substantially zero when the remaining toner amount is less than this. Further, the memory 52 stores the toner lower limit amount W
Corresponding to the _L sensor output V _L and near-end toner amount W _E
The sensor output V _E corresponding to is stored in advance.

FIG. 6 is a flow chart showing a control process for toner circulation between the toner tank and the developing device of this embodiment. When the CPU 51 starts development on the electrostatic latent image formed on the photosensitive drum 14 (step S
1) Based on the detection signal from the toner sensor 35 which is converted into a digital signal by the A / D converter 53, the detection of the toner remaining amount in the toner tank 21 is started (step S2), and the toner remaining amount is below the toner. Judge whether it is more than the limit W _L
(Step S3). When the toner remaining amount is larger than the toner lower limit amount W _L (Yes in step S3), the CPU 51 controls the variable mechanism 37 so that the stirring plate 9 rotates at high speed (step S4), and the preset control cycle is set. The counting of t is started (step S5). When the toner remaining amount is less than the toner lower limit amount W _L (NO in step S3), the variable mechanism 37 is controlled so that the stirring plate 9 rotates at low speed (step S6), and the toner remaining amount is the near end toner. It is determined whether or not the quantity is larger than the quantity W _E (step S7). When the toner remaining amount is larger than the near end toner amount W _E (Yes in step S7), the CPU 51 starts counting the preset control cycle t (step S5).

When the counting of the control period t in step S5 is completed, it is determined whether the remaining amount of toner is larger than the near end toner amount W _E (step S8). CPU51, when the amount of remaining toner is determined to less near-end toner amount W _E at step S8, or if the remaining amount of toner in step S7 is determined as follows near-end toner amount W _E, stops the rotation of the stirring plate 9 respectively After that (step S9), toner end processing is performed (step S10). If it is determined in step S8 that the toner remaining amount is larger than the near end toner amount W _E , the process returns to step S3 and steps S3 to S
The process of 8 is repeated. By the toner end processing in step S10, for example, a display unit (not shown) indicates to the user that it is time to replace the toner cartridge 20, and the apparatus operation is performed after the current image formation is completed. Interlock.

In the electrophotographic recording apparatus of this embodiment, the CP
When U51 rotates the stirring plate 9 at high speed when the remaining amount of toner in the toner tank 21 is larger than the toner lower limit amount W _L , the screw feeder 34 also rotates at high speed and a large amount of toner faces the toner recovery port 24. Transport to near the section. As a result, in a state where the toner cartridge 20 is supplying the toner to the developing device 30 at a predetermined supply speed, the toner circulation amount between the toner tank 21 and the toner storage portion 8 is increased, so that the toner tank 21 and Since it is possible to surely make the concentration of the additive in the toner in the toner storage portion 8 uniform, the high concentration of the additive in the toner storage portion 8 is prevented, and the toner is filled in the toner storage portion 8. It is possible to prevent a decrease in image density caused by an increase in the concentration of the additive in the toner for a long term.

Further, the CPU 51 rotates the stirring plate 9 at a low speed when the remaining amount of the toner in the toner tank 21 is less than the toner lower limit amount W _L , so that the screw feeder 34 also rotates at a low speed to collect the toner in the toner recovery port 24. The ability to convey it to the vicinity of the facing portion is reduced. As a result, the toner cartridge 20
Is supplying toner to the developing device 30 at a speed lower than a predetermined supply speed, it is possible to prevent the toner accumulation amount in the vicinity of the portion facing the toner supply port 25 in the toner storage portion 8 from being significantly reduced. As a result, the toner accumulation amount can be made uniform, which can prevent a decrease in the toner transfer and adhesion amount to the photoconductor drum 14 due to a decrease in the toner accumulation amount in the toner storage portion 8. It is possible to prevent the image density from decreasing at both ends. In this state, the toner tank 21
~ Although the amount of toner circulating between the toner storage portions 8 is reduced,
After the toner in the toner tank 21 has decreased to the toner lower limit amount W _L , the toner cartridge 20 is replaced in a relatively short time, which makes it difficult to increase the concentration of the additive in the toner in the toner storage portion 8. It does not become.

Further, when the near-end toner amount W _E is detected, the rotation of the stirring plate 9 is stopped and the toner supply port is stopped.
The toner storage portion 8 is stopped by stopping the toner conveyance from the portion facing the toner collecting port 24 to the portion facing the toner collecting port 24.
It is possible to prevent all the toner in the vicinity of the portion facing the toner supply port 25 from being conveyed inside, and to prevent the development of the both ends of the electrostatic latent image in the main scanning direction from becoming impossible.

FIG. 7 is a front view showing another example of the screw feeder in the electrophotographic recording apparatus of this embodiment.
The screw feeder 38, which is a reverse-flow toner conveying means, has a winding pitch P ₁ of the conveying portion F _{1 in} the vicinity of a portion facing the toner supply port 25 in the axial direction and an inner side of the conveying portion F ₁ , that is, the toner collecting port 24. Conveying part F ₂ on the opposite side of
Are wound on the outer periphery of the stirring plate 9 so that the winding pitches P ₂ thereof are different from each other. Here, there is a relationship of winding pitch P ₁ <winding pitch P ₂ . As a result, the screw feeder 38 has a higher conveying speed for the toner by the conveying portion F ₂ than the conveying speed for the toner by the conveying portion F ₁ during its rotation. It becomes smaller near the portion facing the toner supply port 25 than on the side facing the recovery port 24. In addition, when the screw feeder 38 is used, as shown in FIG.
It is assumed that the stirring plate 9 is always rotated at a constant speed when developing the electrostatic latent image on the photoconductor drum 14 without controlling the rotation speed of the stirring plate 9 described above.

In the electrophotographic recording apparatus of the present embodiment, the screw feeder 38 is used as the backflow toner conveying means, so that the toner cartridge 20 is supplying toner to the developing device 30 at a speed lower than a predetermined supply speed. ,
Since the toner feeding capability of the screw feeder 38 in the toner storage portion 8 is smaller in the vicinity of the portion facing the toner supply port 25 than in the portion facing the toner recovery port 24, the toner supply port 25 in the toner storage portion 8 is smaller. It is possible to prevent the toner accumulation amount in the vicinity of the opposite portion from being significantly reduced and to make the toner accumulation amount uniform, and as a result, the photosensitive drum is reduced due to the reduction of the toner accumulation amount in the toner storage unit 8. Since it is possible to prevent a decrease in the amount of toner transferred and adhered to 14, it is possible to prevent the image density from decreasing at both ends in the main scanning direction. Further, in the state where the toner cartridge 20 is supplying the toner to the developing device 30 at a predetermined supply speed, the effective contact area of the screw feeder 38 with respect to the toner is increased in the vicinity of the portion facing the toner supply port 25, so that the toner is supplied. The efficiency of toner transportation by the screw feeder 38 is improved in the vicinity of the portion facing the port 25, and the toner accumulation amount in the toner storage portion 8 can be made uniform.

[0031]

As described above, according to the first aspect of the present invention.
According to the electrophotographic recording apparatus described above, the toner circulation control means changes the conveying speed of the one-component toner by the backflow toner conveying means in accordance with the remaining amount of toner in the toner tank, thereby developing the toner cartridge. In accordance with the change in the toner supply speed with respect to, the amount of toner conveyed by the backflow toner conveying means to the vicinity of the portion facing the toner recovery port in the toner storage portion can be controlled. As a result, it is possible to prevent the toner deposition amount in the vicinity of the portion facing the toner supply port in the toner storage unit from being significantly reduced, and to make the toner deposition amount uniform, and to prevent the toner deposition between the toner tank and the toner storage unit. Therefore, the image density of the toner image developed on the photosensitive drum becomes unstable due to the increase of the additive concentration in the toner storage portion or the non-uniformity of the toner accumulation amount. Is prevented from happening.

Further, according to the second aspect of the electrophotographic recording apparatus, the toner circulation control means, when the toner remaining amount in the toner tank becomes equal to or less than the preset near-end toner amount, the backflow toner conveying means. By stopping the operation, it is possible to prevent all the toner in the vicinity of the portion facing the toner supply port in the toner storage portion from being conveyed, and to provide an area in the electrostatic latent image corresponding to the vicinity of the portion facing the toner supply port. Can be prevented from being unable to be developed.

According to another aspect of the electrophotographic recording apparatus of the present invention, the backflow toner conveying means conveys the one-component toner to the vicinity of the portion facing the toner recovery port in the toner storage portion, and the toner supply port. In the state where the toner cartridge is supplying the toner to the developing device at a speed lower than a predetermined supply speed, the toner is stored in the vicinity of the facing portion of the toner collecting port. The amount of toner that can be made uniform by preventing a significant decrease in the amount of toner accumulated in the vicinity of the portion facing the toner supply port inside the unit, and the amount of toner required and sufficient between the toner tank and the toner storage unit Since it can be circulated only for a while, the image density of the toner image developed on the photoconductor drum is increased due to the increase of the additive concentration in the toner storage portion or the non-uniformity of the toner accumulation amount. It is prevented from becoming stable. In a state where the toner cartridge is supplying the toner to the developing unit at a predetermined feed rate, by the backflow conveying means in the vicinity of the opposing portion between the toner supply opening by the expansion of the contact area of the backflow conveying means to the toner The toner transport efficiency is improved, and the toner accumulation amount in the toner storage unit can be made uniform.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of a main part in an embodiment of an electrophotographic recording apparatus of the present invention.

FIG. 2 is a perspective view of a toner cartridge in the electrophotographic recording apparatus of this embodiment.

FIG. 3 is a perspective view of an example of a screw feeder in the electrophotographic recording apparatus of this embodiment.

FIG. 4 is a block diagram showing a configuration of a control unit in the electrophotographic recording apparatus of this embodiment.

FIG. 5 is a characteristic diagram showing the relationship between the detection signal from the toner sensor of the present embodiment and the remaining amount of toner in the toner tank.

FIG. 6 is a flowchart showing a control process for toner circulation between the toner tank and the developing device of the present embodiment.

FIG. 7 is a front view showing another example of the screw feeder in the electrophotographic recording apparatus of the present embodiment.

FIG. 8 is a configuration diagram showing an example of a conventional electrophotographic recording apparatus.

9 is a perspective view of a toner cartridge in the electrophotographic recording apparatus shown in FIG.

[Explanation of symbols]

3 ... Agitator, 4 ... Magnetic roller, 8 ... Toner storage section, 9 ... Stirring plate, 11 ... Developing roller, 13 ... Intermediate roller, 14 ... Photosensitive drum, 20 ... Toner cartridge,
21 ... Toner tank, 22 ... Blade, 23 ... Peeling member, 24 ... Toner recovery port, 25 ... Toner supply port, 30 ...
Developing device, 31 ... Case, 32 ... Toner circulation port, 34, 38 ...
Screw feeder.

Claims (3)

(57) [Claims] 1. A developing unit for transferring a mono-component toner filled in a toner accommodating portion onto an electrophotographic photosensitive member and developing the electrostatic latent image formed on the electrophotographic photosensitive member with the mono-component toner. When, it is detachably attached to the apparatus main body, and the electrophotographic recording apparatus having a toner cartridge for replenishing before <br/> Symbol toner accommodating portion to one-component toner accommodated in the toner tank, wherein A backflow toner that conveys the one-component toner stored in the toner storage portion from both ends of the toner storage portion to the central portion.
-Providing a conveying means in the toner storage section to supply toner to both ends of the toner cartridge in the longitudinal direction.
The toner recovery port is formed at the center of the toner
-The cartridge was removably attached to the device body.
At this time, the toner supply port and toner
An opening is formed in a portion facing the toner recovery port, and the one-component toner is conveyed to the toner supply port side to transfer the toner to the toner supply port.
From the toner supply port to both ends of the toner storage unit.
The toner to the backflow toner transporting means.
Is transported near the portion facing the toner recovery port.
Pass the separation toner through the toner recovery port, and
Back into the tank, and
A toner backflow means for merging the toner into the toner tank.
Provided, the reverse flow of the transport speed of the one-component toner by the conveying means, said electrophotographic recording apparatus so as to correspond to the amount of remaining toner, characterized in that a toner circulation control means for changing in the toner tank. 2. The toner circulation control means stops the backflow toner conveying means when the remaining amount of toner in the toner tank becomes equal to or less than a preset near-end toner amount. 1. The electrophotographic recording device described in 1. 3. A developing unit for transferring the electrostatic latent image formed on the electrophotographic photosensitive member to the electrostatic latent image formed on the electrophotographic photosensitive member by transferring the monocomponent toner filled in the toner storage portion onto the electrophotographic photosensitive member. When, it is detachably attached to the apparatus main body, and the electrophotographic recording apparatus having a toner cartridge for replenishing before <br/> Symbol toner accommodating portion to one-component toner accommodated in the toner tank, wherein A backflow toner that conveys the one-component toner stored in the toner storage portion from both ends of the toner storage portion to the central portion.
-Providing a conveying means in the toner storage section to supply toner to both ends of the toner cartridge in the longitudinal direction.
The toner recovery port is formed at the center of the toner
-The cartridge was removably attached to the device body.
At this time, the toner supply port and toner
An opening is formed in a portion facing the toner recovery port, and the one-component toner is conveyed to the toner supply port side to transfer the toner to the toner supply port.
From the toner supply port to both ends of the toner storage unit.
The toner to the backflow toner transporting means.
Is transported near the portion facing the toner recovery port.
Pass the separation toner through the toner recovery port, and
Back into the tank, and
A toner backflow means for merging the toner into the toner tank.
Provided, electrons the toner conveying ability of the backflow conveying means, and wherein the kite as the than near portion facing the toner <br/> over the supply port becomes large at the opposite side of said toner recovery port Photo recording device.