JP3997083B2 - Agent replenishing device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agent replenishing device that replenishes toner, a toner and carrier mixture or a carrier containing a carrier alone to a predetermined place, and an image forming apparatus such as an electrophotographic printer, facsimile, and copying machine.
[0002]
[Prior art]
Conventionally, as a dry toner or carrier used in an electrophotographic image forming apparatus, or an agent (hereinafter collectively referred to as toner), which is a mixture of toner and carrier, a hard bottle type container is used as a container for storing the toner. It is common. This type of storage container is equipped with an agitator as a toner agitating and discharging means inside, a container with a spiral groove on the container wall surface to rotate and discharge the toner inside, and further discharging There are things that are replenished by hand without having a mechanism.
[0003]
In recent years, environmental issues have been emphasized, and toner storage containers are also required to be collected and recycled. However, the toner storage container of the hard bottle described above has many problems in recoverability and recyclability, such as high transportation cost and difficulty in cleaning even when reused.
[0004]
In view of this, there is a demand for a soft-type toner storage container that can be reduced in volume and made of a flexible material from the viewpoint of recoverability and recyclability. However, dry toner for electrophotography generally has poor fluidity and tends to agglomerate, so that it is very difficult to discharge from a soft container. This is because since the container is soft, it is difficult to add an agitator or a discharge mechanism, and even if a discharge mechanism can be provided, volume reduction of the container is hindered by the discharge mechanism.
[0005]
Japanese Patent Application Laid-Open Nos. 2000-47465, 2000-98721, and the like disclose techniques that can relieve the problems of the conventional image forming apparatus. The toner replenishing devices described in these publications are configured to suck and discharge toner stored in a flexible container by suction pressure (negative pressure) of a suction type powder pump (uniaxial eccentric screw pump). Therefore, even if the toner is stored in a flexible container, it can be replenished to the developing device without any trouble, and since it is flexible, the container can be easily recovered and the transportation cost does not increase. Further, the toner replenishing device is advantageous in that air is supplied into the toner storage container and the toner stored in the air is sufficiently stirred, so that the toner quality can be maintained in a good state. ing.
[0006]
By the way, although recent image forming apparatuses have been made compact, further downsizing is required. Therefore, each part device itself to be used is miniaturized, and the developing device is miniaturized without exception. When the developing device is downsized, the amount of developer that can be stored in the device also becomes small. For example, in the case of a two-component developing device, it is necessary to replenish the toner almost frequently to keep the toner concentration constant. There is a need for a toner replenishing device with a more accurate replenishment amount.
[0007]
Above powder In a toner replenishing device that replenishes toner by operating a pump, the signal from the toner density sensor powder Control is performed so that a predetermined amount of toner is replenished by setting the operation time and operation timing of the pump. Such control is powder This is based on the premise that the pump operating time and toner transport amount are approximately proportional.
[0008]
[Problems to be solved by the invention]
However, the inventor of the present application, as a result of various experiments, powder The pump operation time and the toner transport amount are approximately proportional if the interval from the previous replenishment is longer than a certain time, or if the replenishment amount is greater than a certain amount, but less than the replenishment amount, If the interval between replenishment is shorter than a certain time powder It has been found that the toner conveyance amount becomes unstable with respect to the operation time of the pump. For this reason, when toner is replenished under certain conditions, problems such as the image density fluctuating depending on the replenishment interval have occurred.
[0009]
In view of the above-described conventional problems, an object of the present invention is to provide an agent replenishing device having a high accuracy and a stable replenishment performance for transporting an agent, and an image forming apparatus using the agent replenishing device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an agent storage means for storing a powder agent, and a predetermined place via a conveyance path in which the agent stored in the agent storage means is substantially sealed by negative pressure. And a control means for controlling the operation of the uniaxial eccentric screw pump, and the control means sets the operation timing and the operation time of the uniaxial eccentric screw pump in advance when the agent is replenished. In the agent replenishing device, the control means has an interval from the previous agent replenishment. Predetermined Until the prescribed replenishment interval is exceeded , Replenishment The shorter the interval, the longer the operating time of the uniaxial eccentric screw pump. , Longer supply intervals operating time When the replenishment interval exceeds the predetermined replenishment interval, it is corrected so that it operates for a fixed time longer than the operation time when the replenishment interval is shorter than the predetermined replenishment interval. Do The agent replenishing device characterized by this is proposed.
[0011]
In the present invention, When the predetermined replenishment interval is 100 seconds, the operating time of the uniaxial eccentric screw pump is not corrected when the predetermined opening time is 100 seconds or more, and the operating time of the uniaxial eccentric screw pump is corrected when it is less than 100 seconds. And effective.
[0012]
Furthermore, the present invention provides an air supply means for supplying air into the agent storage means, and the control means Single-shaft eccentric screw pump It is effective to operate the air supply means by assuming that the amount of replenishment of the agent has reached a predetermined amount when the operating time reaches a predetermined time.
[0013]
In order to achieve the above object, the present invention develops a toner storage means for storing powdered toner and the toner stored in the toner storage means via a conveyance path that is substantially sealed by negative pressure. A uniaxial eccentric screw pump transported to the apparatus; a toner concentration detecting means for detecting a developer concentration in the developing apparatus; and a control means for controlling the operation of the uniaxial eccentric screw pump. In the image forming apparatus that controls the toner supply by setting the operation timing and operation time of the uniaxial eccentric screw pump in advance from the toner density detected by the density detection means and the output image data, the control means includes toner density detection The operation time of the uniaxial eccentric screw pump set from the toner concentration detected by the means and the output image data is calculated as the previous agent. Interval from the sheet is Predetermined Until the prescribed replenishment interval is exceeded , Replenishment The shorter the interval, the longer the operating time of the uniaxial eccentric screw pump. , Longer supply intervals operating time When the replenishment interval exceeds the predetermined replenishment interval, it is corrected so that it operates for a fixed time longer than the operation time when the replenishment interval is shorter than the predetermined replenishment interval. Do An image forming apparatus characterized by this is proposed.
[0014]
According to the present invention, the control unit sets the time interval from the previous toner replenishment as a fixed value at the first toner replenishment after the main power supply of the image forming apparatus is turned on. Single-shaft eccentric screw pump It is effective to correct the operation time.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing a color laser printer as an example of an image forming apparatus provided with a toner replenishing device as an agent replenishing device according to the present invention.
[0016]
This color laser printer has a configuration in which a paper feed unit 2 is disposed at the bottom of the apparatus main body 1 and an image forming unit 3 is disposed above the paper feed unit 2. The image forming unit 3 is provided with a transfer belt device arranged so as to be inclined so that the paper feed side is on the bottom and the paper discharge side is on the top. The transfer belt device includes a plurality of rollers 11, in this example, an endless transfer belt 12 wound around four rollers 11, and one of the rollers 11 is driven by a drive source (not shown). The transfer belt 12 is rotated counterclockwise as indicated by an arrow. Four image forming units 4M, 4C, 4Y, and 4Bk for magenta (M), cyan (C), yellow (Y), and black (Bk) are arranged in parallel on the upper running side of the transfer belt 12 from the bottom. Has been.
[0017]
Each of the image forming units 4M, 4C, 4Y, and 4Bk is provided with a photosensitive drum 5 as an image carrier, and the photosensitive drum 5 is driven to rotate clockwise by a driving unit (not shown). Around the photosensitive drum 5, a charging roll 6 as a charging unit, an optical writing unit in which writing by laser light is performed by an optical writing unit 8, a developing unit 10 as a developing unit, and a cleaning unit 9 as a cleaning unit are provided. Yes. The developing device 10 is a two-component developing device composed of toner and a carrier, and the toner is replenished by a toner replenishing device, which will be described later, according to the amount of consumed toner.
[0018]
Next, an image forming operation for performing full color printing of the color printer shown in FIG. 1 will be described.
Each image forming unit drives an LD (laser diode) (not shown) to the photosensitive drum 5 charged by the charging roll 6, irradiates the polygon mirror 8a with laser light, and reflects it through a cylinder lens or the like. Optical writing of an optical image to be developed with toner of each color is performed by an optical writing device 8 that guides light onto the photosensitive drum 5. By this writing, an electrostatic latent image is formed on the photosensitive drum 5 based on image data sent from a host machine such as a personal computer, and the latent image becomes a visible toner image by the developing device 10.
[0019]
On the other hand, a sheet designated as a transfer material is fed from the sheet feeding unit 2, and the fed sheet is once abutted against a registration roller 13 provided on the upstream side in the transport direction of the transfer belt 12, and then The toner is fed onto the transfer belt 12 in synchronism with the visible image, and reaches the transfer position facing the photosensitive drum 5 as the belt travels. At this transfer position, the visible image of the magenta toner is first transferred onto the paper by the action of the transfer roll 14 disposed on the back side of the transfer belt 12.
[0020]
In the same manner as described above, in the other image forming units 4C, 4Y, and 4Bk, visible images are formed by the respective toners on the surfaces of the respective photosensitive drums 5, and these visible images are conveyed by the transfer belt 12. Is transferred to each transfer position each time. Therefore, this color printer transfers a full color image, which is an advantage of the tandem type, onto a sheet in a short time almost the same as monochrome. The transferred paper is separated from the transfer belt 12 and fixed by the fixing device 15. The sheet after fixing is normally discharged out of the apparatus as it is, or at this time, the sheet is reversed and discharged on the back side to a discharge tray 16 provided on the upper surface of the apparatus body 1. Backside paper discharge is an almost indispensable condition for the printer to arrange prints in page order.
[0021]
The developing device 10 is a two-component developing device, monitors the mixing ratio of toner and carrier in the device, and replenishes the shortage when the toner is insufficient. In such toner replenishment, the toner stored in the toner storage container 20 as the agent storage means disposed at a position away from the developing device, in this example, the upper right in FIG. 1, is supplied by the toner supply device as the agent supply device. It is configured.
[0022]
Next, the toner replenishing device will be described in detail with reference to FIG.
The developing device 10 is provided with a uniaxial eccentric screw pump that is a suction type powder pump 40 in the vicinity or integrally therewith. The powder pump 40 has a structure in which a rotor 41 made of a screw eccentric with a rigid material such as metal and a two-screw through hole are formed, and a stator made of an elastic body such as rubber. 42 and a holder 43 made of a resin material or the like that holds the stator 42 so as not to rotate and forms a powder conveyance path. As shown in FIG. 3, the rotor 41 is connected to a drive shaft 44 connected by a pin joint that absorbs the eccentric motion, and a gear 45 is fixed to the drive shaft 44. The drive to the gear 45 is a clutch. It is interrupted by turning on and off 46.
[0023]
Further, a toner suction portion 47 is provided at the tip of the holder 43, that is, the right end in FIG. 2, and is connected by the toner suction portion 47 and a toner connection port 54 provided in a nozzle 51 described later and the toner transport tube 17. ing. It is extremely effective to use a flexible tube made of a rubber material (for example, polyurethane, nitrile, EPDM, silicon, etc.) having a diameter of 4 mm to 10 mm and excellent in toner resistance as the toner conveying tube 17. If it is a flexible tube, piping can be easily performed in any direction, up, down, left and right.
[0024]
On the other hand, the toner storage container 20 storing the toner to be replenished to the developing device 10 is set in a container holder 50 of a setting unit, and a nozzle 51 having a circular cross section inserted into the toner storage container 20 is inserted in the container holder 50. Is erected. The toner storage container 20 is set from above onto a container holder 50 which is a set part of the image forming apparatus main body 1, whereby the nozzle 51 is inserted into the container. The nozzle 51 is formed with a pointed portion 52 having a conical section at the top, and has a single tube structure inside, and a passage 53 that serves both as an air flow path and a toner passage is formed. The lower end of the nozzle 51 is mounted with the above-described toner transport tube 17, and the passage 53 has an air inlet 54 formed above it.
[0025]
An air pump 30 as an air supply means is connected to the air inlet 54 via an air transfer pipe 31. The air pump 30 is used to generate a flow rate of about 1 to 3 liters per minute. When the air pump 30 is activated, the air pump 30 is connected to the lower portion of the toner storage container 20 through the air transfer pipe 31 and the air inflow passage 53. Air is ejected from the side. The air jetted into the toner storage container 20 passes through the stored toner layer, and fluidizes like a liquid while stirring the poorly fluid toner. The air transfer pipe 31 is provided with an opening / closing valve 32 for preventing toner from entering the air pump.
[0026]
The toner storage container 20 in the present embodiment is a back-in-box type having an outer box 21 as a protective case and a toner bag 22 as a flexible and deformable container body detachably housed in the outer box 21. It is configured. The outer box 21 is made of a material such as paper, cardboard, or resin having rigidity, and has an internal space that can accommodate the toner bag 22. In addition, the bag portion of the toner bag 22 is made of a flexible sheet material (thickness of about 80 to 200 μm) such as a polyester film or a polyethylene film, and the inflow and outflow of air made as in origami production with a single-layer or multi-layer structure. There is no sealed bag-like container shape. Further, in order to easily discharge the stored toner, it is formed in a tapered shape that is narrowed down from an appropriate middle portion in the vertical direction toward a discharge port at the bottom. A base member 23 made of resin such as polyethylene or nylon is provided at the tapered lower center of the toner bag 22, and the base member 23 includes a case 24 made of resin such as polyethylene or nylon and a sponge or the like. It is comprised with the sealing material 25 which consists of elastic members, such as rubber | gum. For the case 24 and the sealing material 25, it is desirable to use members of the same system from the viewpoint of recycling, and welding to the bag container can be facilitated. Further, the sealing material 25 has a cross-shaped slit, which is in close contact with the nozzle 51 with the nozzle 51 inserted, and can prevent toner leakage from the toner storage container 20 to the outside of the apparatus. Even when the storage container 20 is taken out, the slit of the sealing material closes due to its elasticity, thereby preventing toner leakage. The length of the slit is about the same diameter as the outer diameter of the nozzle 51 to 3 mm, and the sealing material 25 and the case 24 are bonded by a double-sided adhesive tape or the like. Note that it is preferable to use a sealing material 25 having a toner resistance, a very low air permeation, and an excellent creep strength.
[0027]
The toner container 20 configured as described above not only protects the toner bag 22 from an external impact and the like by being stored in the outer box 21 even if the toner bag 22 storing the toner is flexible. In addition, since the handling property is improved, it is easy to handle the container, and it is possible to obtain the advantage that the storage is easy to organize.
[0028]
The toner replenishing device configured as described above powder Due to the rotation of the rotor 41 of the pump 40, a strong self-suction force (suction pressure) is generated in the pump, and the toner can be sucked from the toner storage container 20. The toner in the toner storage container 20 drops from time to time near the nozzle 51 due to gravity, and the toner is transferred to the outside of the container using the suction force of the powder pump 40, but the electrophotographic toner has poor fluidity. After the toner near the nozzle is sucked by the powder pump 40, there is a concern that a cross-linking phenomenon occurs in the container. By supplying air from the air pump 30 to the inside of the toner storage container 20, the toner is agitated and fluidized. To prevent the toner from cross-linking. Therefore, even if cross-linking occurs in the toner storage container 20, it can be broken down by air, so that it is possible to stabilize the amount of toner replenishment and reduce the remaining amount of toner in the container.
[0029]
FIG. 3 is a control system block diagram relating to toner supply in the image forming apparatus.
This toner replenishing device has a micro processing unit (hereinafter referred to as MPU) as a control means for controlling the drive using a conventionally known developer concentration detection method. In this example, the developing device 10 is provided with a magnetic permeability detector 35 that detects a change in the mixing ratio of the toner and the carrier as a toner concentration detection means, and the MPU detects a result of the magnetic permeability detector 35 that detects the image density. Is captured. In this control method, the detection result of the permeability detector 35 and the image data (number of pixels) are used. powder A toner replenishment signal in which the operation time of the pump 40 is set is issued.
[0030]
When the toner replenishment signal is issued, the clutch 46 is turned on, a rotational driving force is transmitted from the drive source (not shown) of the image forming apparatus to the drive shaft 45, and the powder pump 40 operates for the set time. powder When the pump 40 is operated, a predetermined amount of toner in the toner container 20 is supplied to the developing device 10 by the suction negative pressure generated thereby. The toner concentration detection means is not limited to a magnetic permeability detector, and may be one that detects the reflection density of the toner image on the photosensitive member. Also, powder The pump 40 can be driven by a unique motor without providing a clutch.
[0031]
Further, the MPU also controls the air pump 30, and the air supply control is performed when the accumulated operating time of the powder pump 40 reaches a predetermined value (for example, accumulated 1 sec) as shown in FIG. Immediately after stopping 40, the air pump 30 is operated. Here, the air pump 30 is not moved simultaneously with the powder pump 40. As shown in FIG. 5, when the air pump 30 is driven simultaneously with the powder pump 40, the air is sent to the powder pump 40 side, and the toner in the container 20 may not be sufficiently stirred.
[0032]
In addition, powder The toner sucked by the pump 40 falls into the developing device through a toner introduction hole 10a provided in a part of the developing device 10, and is transferred to the developing unit by a stirring and conveying member (not shown) inside the developing device. When the two-component development method is used, the toner replenished during the transfer process is agitated and mixed with the developer in the developing device, so that a uniform agent concentration and an appropriate charge amount are obtained.
[0033]
In addition, as shown in FIG. 6, it is also possible to provide a breathable filter 26 on the upper part of the toner bag 22, thereby reducing the rise in the inside of the container to a positive pressure due to the air supplied from the air pump 30 described above. To play a role.
[0034]
By the way, the control of the toner replenishing device is as follows. powder This is based on the fact that the uniaxial eccentric screw pump which is the pump 40 is capable of continuous quantitative transfer at a high solid-gas ratio and can obtain an accurate toner conveyance amount proportional to the rotational speed of the rotor 41. However, the inventor of the present application investigated whether the replenishment amount of the uniaxial eccentric screw pump always becomes a substantially constant amount proportional to the rotational speed of the rotor 41 under various conditions using the toner replenishing device.
[0035]
As a result, as shown in FIG. 7, it has been found that when the conveyance interval is shorter than the previous toner conveyance, the toner conveyance is increased and the conveyance amount of the uniaxial eccentric screw pump is not always substantially constant. In FIG. powder The driving condition of the pump 40 was 270 rpm, the clutch on time was 0.2 seconds, and the transport amount was an average value obtained 100 times under the same conditions.
[0036]
As is apparent from FIG. 7, the replenishment amount of the toner replenishing device becomes almost constant when the replenishment interval from the previous time is 100 seconds or more, but when it is less than 100 seconds, the toner replenishment amount increases as the interval decreases. I found out. In other words, it has been found that the replenishment amount of the toner replenishing device increases as the replenishment interval from the previous time is shorter, stabilizes slightly when the interval reaches 60 seconds, and becomes substantially constant when the interval exceeds 100 seconds. The main cause of such a variation in the toner replenishment amount is that air is contained and the fluidity is good when the toner is being transported, but the air escapes and sinks with the lapse of time when the toner is stopped, and the fluidity is lowered. It is assumed that
[0037]
Therefore, the toner replenishing device is controlled by the MPU according to the flowchart shown in FIG. In FIG. 8, the output of the magnetic permeability detector 35 is read (step 1), and the image data is read (step 2). The toner consumption is calculated from the toner density and the number of pixels of the image data (step 3). Here, data relating to the replenishment interval, that is, the time that has been stopped since the last replenishment is read (step 4). Then, the driving time of the clutch 46 corresponding to the toner replenishing amount is calculated (step 5). Since the driving time is taken in step 4 since the replenishing interval data is taken in, the replenishing interval is shorter than 100 seconds. The driving time is also shortened, whereby the driving time that can replenish the target amount of toner is calculated. The calculated driving time is added to the accumulated time (step 6). Then, the clutch 46 is turned on (step 7), and the turned on clutch 46 is turned off when the calculated time is reached (step 8).
[0038]
The accumulated time in step 6 is monitored and used for controlling the air pump 30, and it is determined whether or not the accumulated time has reached a predetermined time N seconds (step 9). When the accumulated time reaches the predetermined time N seconds, the air pump 30 is driven to supply air to the toner container 20 (step 10), and the accumulated time is cleared to zero (step 11). Further, when the driving time of the clutch 46 does not exceed N seconds in step 9, the process is ended. In step 7 of the control flow, the timing is controlled so that the clutch 46 is not turned on when the air pump 30 is operated.
[0039]
Thus, by controlling the toner replenishing device, it is possible to always replenish the required amount of toner. In such control, the data shown in FIG. 9 is a data table showing the replenishment time when the three types of toner consumption conditions are different.
[0040]
In FIG. 9, a is 0.02 g, b is 0.1 g, and c is 0.3 g of toner. When the replenishment interval is 0, a is 0.1 second, b is 0.2 second, c is 0.5 seconds. FIG. 9 shows the driving time (unit: msec) of the clutch 46 when the replenishment interval is 4 seconds, 10 seconds, 20 seconds, 40 seconds, 65 seconds, 100 seconds, 180 seconds, and 1000 seconds. As is apparent from this table, the replenishment amount for all of a, b, and c is 100 seconds until the replenishment interval reaches 100 seconds. Increase Therefore, the drive time of the clutch 46 is set to compensate for this. Short By controlling in this way, all the replenishment amounts in each row can be made substantially equal to 0.02 g, b is 0.1 g, and c is 0.3 g. In addition, when the replenishment interval exceeds 100 seconds for a, b, and c, the change in the toner conveyance amount due to the replenishment interval is eliminated, and the clutch 46 is driven for a certain time. Since the replenishment interval, toner density, and image data conditions in actual control are continuous numerical values, it is effective to calculate the replenishment time by formulating the relationship between these parameters in advance.
[0041]
By the way, as apparent from the graph of FIG. 7 and the table of FIG. 9, when the replenishment interval exceeds 60 seconds, powder When the replenishment amount of the pump 40 approaches almost constant and the replenishment interval exceeds 100 seconds, it converges almost constant. Therefore, when the replenishment interval is 60 seconds and exceeds 100 seconds for further accuracy, the above-described replenishment time calculation formula can be simplified by using a predetermined replenishment time.
[0042]
The replenishment time is measured using the timer function of the MPU. For this reason, when the power of the image forming apparatus is turned off, the replenishment interval from the previous time cannot be determined. However, when the power is turned off, the replenishment interval from the previous time at the first toner replenishment after the power is turned on mostly exceeds 60 seconds. Accordingly, the replenishment time can be set on the assumption that the replenishment interval exceeds 60 seconds or even 100 seconds at the first toner replenishment after the power is turned on.
[0043]
In addition, for more accuracy, an independent power source may be provided in the image forming apparatus, and the MPU may be kept on by the independent power source even when the main power source is turned off, so that the replenishment interval from the previous time can be accurately detected. it can. Furthermore, timer means having a lower power than that of the MPU may be provided and operated by an independent power source (battery) to detect the replenishment interval. If comprised in this way, power consumption can be reduced rather than counting by MPU at the time of a power-off or sleeping mode.
[0044]
FIG. 10 shows the experimental results of measuring the replenishment amount by changing the replenishment interval, as in FIG. powder The peristaltic conditions of the pump 40 were 270 rpm and the clutch on time was 0.5 seconds. As in FIG. 7, the replenishment amount is plotted as the average replenishment amount obtained by repeating the same conditions 100 times. However, FIG. 7 and FIG. 10 differ in the range of the average replenishment amount.
[0045]
When the replenishment amount per time is large, such as 0.5 g in FIG. 10 or 0.3 g in FIG. 9 c, the decrease in the replenishment amount due to the difference in the replenishment interval is very small compared to the case where the replenishment amount is smaller than that. . This means that the replenishment amount is large powder The operating time of the pump 40 is activated. powder The uniaxial eccentric screw pump, which is a pump, increases the toner replenishment amount at start-up and then stabilizes to a constant amount, but operating for a long time mostly uses a stable region, so there is little decrease in the replenishment amount Is. On the contrary, when a small amount of toner is replenished by rotating the rotor several tens of degrees, the previous replenishment interval is easily affected.
[0046]
Therefore, when the toner replenishment amount is large, control may be performed by taking in replenishment interval data as shown in the flow of FIG. 8, or may be controlled only by the set toner consumption without considering the replenishment interval. . The former control provides accurate toner supply, the latter control is simplified, and the accuracy is inferior to the former, but the difference is negligible.
[0047]
In the above toner replenishing device, when a predetermined amount of toner, for example, 2 g, is replenished, it is advantageous in that the air pump 30 is operated to supply an appropriate amount of air into the toner storage container 20 in terms of good toner conveyance and reducing residual toner. It is recognized from various experiments. However, if the air supply is excessive, the supplied air flows into the toner transport tube 17 and pushes the toner in the tube. Also, the supplied toner flows directly into the tube and pushes in the toner. If this phenomenon continues several times, the toner in the tube is hardened. powder The pump 40 generates a “clogging” that prevents toner from being conveyed.
[0048]
For this reason, it is important to accurately know the amount of toner replenishment, but it is extremely difficult to detect this directly. Therefore, the toner replenishment amount is powder The operation time of the pump 40 is estimated as a cumulative time. Such estimation of the toner replenishment amount is performed at the replenishment interval as described above. powder When the control for correcting the operation time of the pump 40 is performed, if the actual operation time is accumulated, there is a high possibility that it is determined that the toner conveyance amount has reached the predetermined amount by an amount smaller than the predetermined amount. Explaining this, for example, when the amount of toner x is replenished, the operating time t of the powder pump 40 is set. However, the operation time t + t1 of the powder pump 40 may be corrected from the replenishment interval from the previous time. At this time, powder The accumulated time of the pump 40 is increased by t1 and is actually counted as having been replenished with x + x1 (replenishment amount for the operation time t1) although only x amount is replenished. Therefore, it is determined that the predetermined amount has been supplied before the toner supply amount reaches the predetermined amount, and air is supplied, which may cause a problem of excessive air.
[0049]
Therefore, in the present embodiment, the control of the air pump 30 is performed based on the flow of FIG.
Steps 1 to 3 are the same as the flow of FIG. powder The operating time of the pump 40 is set. Then, the set operation time is added to the accumulated time (step 5). Next, the replenishment interval is read (step 6), the operation time of the clutch 46 is corrected (step 7), and the clutch 46 is turned on (step 8) and turned off (step 9). Next, it is determined whether or not the cumulative time of operation of the clutch has reached a predetermined time N (step 10), and if it has reached N time, the air pump 30 is operated (step 11). Clear (step 12).
[0050]
Thus, by setting the operation time of the toner replenishment amount set according to the toner replenishment amount as the cumulative time, the air pump 30 can be supplied with an appropriate amount of air to the toner storage container 20. More specifically, this control is assumed to be 0.1 g, for example, under the toner consumption condition of FIG. In addition, the air supply is performed once in a replenishment cumulative time of 4 seconds (the aim is air supply for every 2 g of toner replenishment amount). If the replenishment interval is constant at 100 seconds, 320 msec is an appropriate value for the actual replenishment clutch on time, and 0.1 g of toner is replenished. Here, if the actual replenishment time accumulation is used, if it continues 13 times, it will be 4.16 seconds, exceeding 4 seconds, but the cumulative toner replenishment amount is 1.3 g for 13 times. In other words, air supply is performed every 1.3 g of toner supply, which is different from the aim. Similarly, when the supply interval is 10 seconds, the supply time is 250 msec, and air is supplied every 1.6 g of toner supply amount of 16 times. However, even if the interval is 40 seconds or 10 seconds, if the accumulated time is counted with a replenishment time of 200 msec when the interval is 0, the replenishment accumulated time is 4 seconds with 20 replenishments. Is supplied. The cumulative toner replenishment amount at this time is also 2 g because 0.1 g of replenishment is actually performed 20 times, which is consistent with the target (constant).
[0051]
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to the said embodiment, Various modifications can be made.
For example, in the above embodiment, the toner replenishing device that replenishes toner to the developing device has been described as the agent replenishing device. However, the present invention can also be applied to a device that replenishes toner to the hopper of the developing device, and is not limited to toner. The present invention can also be applied to a developer composed of toner and a carrier and replenishment of only the carrier.
[0052]
【The invention's effect】
According to the structure of Claim 1, a control means sets based on the space | interval of time from the last agent replenishment. Single-shaft eccentric screw pump Therefore, the difference in the amount of replenishment caused by the length of the standing time can be corrected, and a stable and stable agent replenishment amount can always be ensured.
[0053]
According to the configuration of claim 2, the control means does not correct the operation time of the suction means when the time interval from the previous agent replenishment is 100 seconds or more, and the operation of the suction means is less than 100 seconds. Since the time is corrected, it is accurately corrected when the leaving time when the replenishment amount fluctuates is less than 100 seconds, and is not corrected when the replenishment amount is less than 100 seconds, and control is facilitated.
[0054]
According to the configuration of claim 3, the air supply means for supplying air is provided in the agent storage means, and the control means is set. Single-shaft eccentric screw pump Since the air supply means is operated assuming that the agent replenishment amount has reached the predetermined amount when the operation time of the time reaches the predetermined time, the assumed amount is not actually counted because the agent replenishment amount is not counted in the corrected operation time. The amount almost matches the amount, and problems such as excessive air can be avoided.
[0055]
According to the configuration of the fourth aspect, the control unit is set based on the toner density detected by the toner density detection unit and the output image data. Single-shaft eccentric screw pump Is corrected based on the data of the time interval from the previous toner replenishment, so that the replenishment amount due to the difference in the leaving time is corrected and stable highly accurate toner replenishment can be obtained.
[0066]
Claim 5 With this configuration, since the time interval from the previous toner replenishment is fixed at the first toner replenishment after the main power of the image forming apparatus is turned on, the control is easy and an error in the replenishment amount due to this is generated. Nor.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an outline of an entire image forming apparatus according to the present invention.
FIG. 2 is an explanatory cross-sectional view of a toner supply device of the present invention.
FIG. 3 is a block diagram showing control means of the present invention.
[Fig. 4] powder It is a timing chart which shows the preferable timing of a pump and an air pump.
[Figure 5] powder It is a timing chart which shows the problematic timing of a pump and an air pump.
FIG. 6 is a perspective view illustrating a toner bag of a toner storage container.
FIG. 7 is a graph showing a relationship between a supply interval and a toner supply amount.
FIG. 8 is a flowchart showing a flow of control by the control means.
FIG. 9 is a table showing the relationship of replenishment time for each replenishment interval.
FIG. 10 is a graph showing a relationship between a replenishment interval and a toner replenishment amount under conditions different from those in FIG.
11A and 11B show another embodiment of the nozzle, where FIG. 11A is a front view and FIG. 11B is a cross-sectional view.
12 is a flowchart showing a flow of control of an operation different from that of FIG. 8 by the control means.
[Explanation of symbols]
10 Developer
20 Toner container
22 Toner Bag
30 Air pump
40 powder pump

Claims (5)

Agent storage means for storing powder agent, uniaxial eccentric screw pump for conveying the agent stored in the agent storage means to a predetermined place via a substantially sealed conveyance path by negative pressure, and the uniaxial eccentricity Control means for controlling the operation of the screw pump, the control means in the agent replenishment device in which the operation timing and the operation time of the uniaxial eccentric screw pump is set in advance when the agent is replenished,
The control means sets the operating time of the uniaxial eccentric screw pump as the replenishment interval is longer than the predetermined replenishment interval until the interval from the previous agent replenishment exceeds a predetermined replenishment interval . Try to shorten the operating time ,
When the replenishment interval exceeds the predetermined replenishment interval, the replenishment interval operates for a fixed time longer than the operation time when the replenishment interval is shorter than the predetermined replenishment interval.
The agent replenishing device characterized by correcting as follows .   The agent replenishing device according to claim 1, wherein the predetermined replenishment interval is 100 seconds, and the operating time of the uniaxial eccentric screw pump is not corrected when the predetermined replenishment interval is opened for 100 seconds or more, and when it is less than 100 seconds, An agent replenishing device which corrects an operation time of a uniaxial eccentric screw pump.   2. The agent replenishing apparatus according to claim 1, wherein air supply means for supplying air is provided in the agent storage means, and the control means supplies the agent when the set operation time of the uniaxial eccentric screw pump reaches a predetermined time. The agent replenishing device characterized in that the air supply means is operated assuming that the amount reaches a predetermined amount. A toner storage means for storing powder toner, a uniaxial eccentric screw pump for transporting the toner stored in the toner storage means to the developing device through a substantially sealed transport path by a negative pressure, and the inside of the developing device And a control unit for controlling the operation of the uniaxial eccentric screw pump. The control unit detects the toner concentration detected by the toner concentration detection unit and the output image. In the image forming apparatus for controlling the toner supply by setting the operation timing and operation time of the uniaxial eccentric screw pump in advance from the data,
The control means sets the operating time of the uniaxial eccentric screw pump set from the toner density detected by the toner density detecting means and the output image data to a predetermined supply interval in which an interval from the previous agent supply is predetermined. Until the replenishment interval is shorter, the operation time of the uniaxial eccentric screw pump is made shorter than the operation time at a longer replenishment interval ,
When the replenishment interval exceeds the predetermined replenishment interval, the replenishment interval operates for a fixed time longer than the operation time when the replenishment interval is shorter than the predetermined replenishment interval.
The image forming apparatus is corrected as described above .   The control means corrects the operation time of the uniaxial eccentric screw pump with a fixed time interval from the previous toner supply at the first toner supply after the main power supply of the image forming apparatus is turned on. 5. The image forming apparatus according to 4.

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