JP2006220984A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus providing a high-quality image without exerting influence on image density even in compact and simple toner supply means constitution. <P>SOLUTION: The image forming apparatus stores a supply amount of toner supplied to a developing device 1 from a sub toner container 3 in the case of supplying the toner to the sub toner container 3 from a main toner container 5 by executing recovery sequence, and makes control to keep not only the amount of the toner in the developing device but also the image density at a prescribed rate by correcting the supply amount stored before when forming an image after the recovery sequence. Even in the case of performing toner supply at two stages by the same driving source, therefore, the apparatus does not exert the influence on image quality. Miniaturization, the reduction of cost and the high quality are thereby realized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus for recording an image on a medium such as paper such as a copying machine, a laser printer, and a facsimile machine.

  Conventionally, in this type of image forming apparatus, a dry developer as a developer is carried on the surface of the developer carrying member, and the developer is conveyed and supplied near the surface of the image carrying member carrying the electrostatic latent image. A method for developing and developing an electrostatic latent image while applying an alternating (alternate) electric field between an image carrier and a developer carrier is well known, and a developing sleeve is used as the developer carrier. In general, a photosensitive drum is used as the image carrier.

  As a developing method, for example, a developer (two-component developer) composed of a two-component composition (carrier particles and toner particles) is used, and a magnetic brush is formed on the surface of a developing sleeve in which a magnet is disposed. The magnetic brush is rubbed or brought close to the opposing photosensitive drum while maintaining a gap, and an alternating electric field is continuously applied between the developing sleeve and the photosensitive drum (between SD) to develop the toner particles on the developing sleeve side. There is known a so-called magnetic brush development method in which development is performed by repeatedly performing transition and reverse transition from the toner to the photosensitive drum (see, for example, Patent Documents 1 and 2).

  The configurations of the developing unit and toner supply means for developing the two-component magnetic brush will be described below.

  FIG. 8 is a schematic cross-sectional view of the developing device and toner replenishing means. 501 is a developing sleeve, 502 is a magnet roller fixedly arranged in the developing sleeve 501, 503 is a developing screw, 504 is a stirring screw, 505 is a developing container, 505a is a toner receiving hole, 505b is a developing chamber, 505c is a stirring chamber, 506 is a regulating blade arranged to form a thin layer of developer on the surface of the developing sleeve 501, and 507 is a photosensitive drum, as illustrated. The developing sleeve 501 is disposed close to the photosensitive drum 507, rotates in the opposite direction or the same direction as the photosensitive drum 507, and is set so that development can be performed in a state where the developer (shown by hatching) is in contact with the photosensitive drum 507. Has been.

  401 is a sub-toner container for storing toner, 402 is a toner supply port that is formed above the sub-toner container 401 and can receive the supply of toner, and 403 has a cylindrical shape that projects substantially horizontally below the sub-toner container 401. A toner conveying pipe formed and capable of conveying toner from the sub-toner container 401, 404 is a replenishing screw that is rotatably provided in the toner conveying pipe 403 and has a spiral surface formed, and 405 rotationally drives the replenishing screw 404. A driving unit 406 is a toner sensor that directly or electrically detects the presence or absence of toner, and 407 is an agitating member that is movably provided inside the sub toner container 401.

  Reference numeral 410 denotes a main toner container provided on the upper portion of the sub-toner container 401, 411 denotes a stirring member rotatably provided in the main toner container 410, and 412 denotes driving means for driving the stirring member 411 to rotate.

  Hereinafter, an image forming operation in the developing device will be described.

  A developer container 505 contains a developer in which toner particles and a magnetic carrier are mixed. The mixing ratio of toner particles and magnetic carrier (hereinafter referred to as T / C ratio) is determined by the amount of toner consumed by development. The appropriate amount of toner is fixed by dropping from the sub-toner container 401 storing the replenishing toner through the receiving hole 505a of the developing container 505 to the agitating chamber provided with the agitating screw 504 by the replenishing screw 404. It is kept in. Various methods for detecting and maintaining the mixing ratio of the toner particles and the magnetic carrier in the developing container 505 at this time have been put into practical use.

  Although the configuration of the developing unit for developing the two-component magnetic brush has been described above, various other methods such as a one-component contact developing method have been put to practical use.

  Hereinafter, an operation of replenishing the toner in the sub toner container 401 when the toner in the sub toner container 401 is reduced as the toner is consumed will be described.

  The agitating member 407 has a function of loosening the toner in order to prevent the toner from solidifying in the sub toner container 401 by rotating or rotating. The replenishing screw 404 transports the toner in the sub-toner container 401 toward the hole 505a communicating with the developing container 505 in the longitudinal direction (direction parallel to the paper surface) and pushes the toner out of the hole and falls to the developing container 505. It is provided to make it act.

  If the toner sensor 406 detects the absence of toner, and the stirring member 407 operates and the state where there is no toner continues, the toner is not solidified in a part of the sub-toner container 401 but the toner is truly Judge that it is gone. If it is determined that there is no toner in the sub toner container 401, the stirring member 411 in the main toner container 410 rotates to replenish the toner from the main toner container 410 to the sub toner container 401.

  In order to prevent the toner from solidifying in the main toner container 410 due to the rotation of the stirring member 411, the action of loosening the toner and toward the toner supply port 402 that communicates the toner in the main toner container 410 to the sub toner container 401. It is provided for the purpose of transporting in the longitudinal direction (direction parallel to the paper surface) and the function of pushing the toner out of its hole and dropping it into the sub-toner container 401. For example, a sheet material such as PET is generally used. is there. The rotation of the stirring member 411 of the main toner container 410 continues until the toner sensor 406 detects the presence of toner, and after the presence of toner is detected, the toner is continuously supplied from the sub toner container 401 via the supply screw 404. .

  Here, the case where the stirring member rotates after the toner sensor detects the absence of toner has been described. However, since the stirring member is a sheet material, the toner is not pushed into the sub toner container more than necessary, and before the detection of the absence of toner. Even if the stirring member rotates, there is no problem.

  Further, if the toner sensor 406 does not detect the presence of toner even if the stirring member 411 of the sub toner container 410 is rotated for a sufficient time, the toner is not replenished to the sub toner container 401. That is, it can be determined that the main toner container 410 has run out of toner, and the user is notified of the absence of toner through display means such as an operation panel (not shown).

  The main toner container 410 may be detachable or fixed to the apparatus. When the toner is detachable, the main toner container 410 is generally called a toner cartridge. When the toner runs out, the main toner container 410 is filled with the toner by replacing the entire toner container 410. When the toner is fixed to the apparatus, the main toner container 410 is directly filled with toner from another toner container.

  The replenishing screw 404 is rotated by the driving unit 405, and the number of rotations or rotation time is set according to the amount of toner requested by the developing device. When the set number of rotations or rotation time is reached, the rotation stops. As a result, as much toner as requested by the developing device is conveyed, and the toner is supplied to the developing container. At this time, the amount of toner transport per rotation or unit time is set in advance according to the size of each toner replenishing screw, and control for calculating the number of rotations or the rotation time according to the required amount is possible. It has become.

  Here, since the amount of toner transported by the screw is proportional to the number of rotations of the screw, in order to set the rotation time, it is assumed that the screw driving means can always rotate the screw at a constant speed. If a means for counting the number of rotations of the screw is provided, the rotation speed of the screw can be set by the number of rotations, whether it is constant or not.

  In FIG. 6, in order to make the drawing easier to see, the longitudinal directions of the photosensitive drum 507 and the developing container 505 are perpendicular to the paper surface, and the longitudinal directions of the sub toner container 401, the replenishing screw 404, and the main toner container 410 are parallel to the paper surface. However, in general, these longitudinal directions are generally the same direction.

  FIG. 9 shows a quadruple tandem image forming apparatus, in which 501 is a first color, 502 is a second color, 503 is a third color, 504 is a fourth color developer and a toner replenishing unit. The configuration is the same as that shown in FIG. As shown in FIG. 8, full-color printing is possible by connecting the developing devices for four colors and the toner supply means. In the case of this system, the recording paper or the intermediate transfer medium moves in the direction indicated by the arrow and the images of the respective colors are overlapped. Therefore, each color is delayed by the time the recording paper or the intermediate transfer medium moves to perform the image forming operation. .

  The photosensitive drum is always rotating because it is in contact with the recording paper or the intermediate transfer medium. However, the stirring screw and the developing screw in the developing unit require the required time during the image forming operation to minimize the deterioration of the developer. It is common to rotate only.

  When the operation of replenishing toner from the sub-toner container to the developing device with the stirring screw and developing screw in the developing device stopped, the replenished toner stagnates in the vicinity of the replenishing port, causing clogging of the toner and T in the developing device. Since this causes non-uniformity of the / C ratio, it is essential to perform an operation of supplying toner from the sub-toner container to the developing device while the stirring screw and the developing screw in the developing device are always rotating.

  FIG. 10 shows the time during which the agitating screw and the developing screw in the developing device are rotating. T in the drawing corresponds to the time during which the recording paper or the intermediate transfer medium moves along the dimension P in FIG. Accordingly, as shown in FIG. 10, while the agitating screw and the developing screw in each color developing device are rotating, the corresponding motor is rotated in the A1 direction, and the replenishing screw of the toner replenishing means is rotated to remove the developing device from the sub toner container. The operation of replenishing toner is performed, and the stirring operation is performed by rotating the motor in the B1 direction as necessary using the other time.

JP-A-55-032060 JP 59-165082 A

  In order to further simplify the configuration from the above conventional example and to realize a small and low-priced toner replenishing means, when the drive motor makes one revolution, the amount of toner replenished from the sub toner container to the developing device is larger than the amount of toner from the main toner container. Consider a configuration in which the amount of replenishment to the container is sufficiently large so that the switching mechanism and the clutch mechanism by the lever are omitted with the same drive source.

  In the realization of this configuration, when the toner in the sub toner container runs out, the drive motor is rotated to replenish the toner from the main toner container to the sub toner container (recovery sequence), and the replenishment from the sub toner container to the developing device is the same. Since the toner is driven by the driving source, the toner is also conveyed to the developing device, and there arises a problem that the image density ratio is deviated from a predetermined amount.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can supply a high-quality image without affecting the image density even with a small and simple toner replenishing means configuration.

  In order to solve the above problems, in the present invention, when a recovery sequence is executed and toner is supplied from the main toner container to the sub toner container, the amount of toner supplied from the sub toner container to the developing device is stored, In the image formation after the recovery sequence, the stored replenishment amount is corrected to control the toner amount in the developing device, that is, the image density to keep the image density at a predetermined ratio.

  According to the present invention, even if two stages of toner supply are executed with the same drive source, the image quality is not affected, and downsizing, cost reduction, and high quality can be realized.

  Embodiments of the present invention will be described below. Since the image forming method and the like of the developing device are the same as those in the conventional example, description thereof will be omitted, and only the toner replenishing means that is a feature of the present invention will be described in comparison with the conventional example.

<Embodiment 1>
FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a developing device capable of developing the developer stored inside into a visible image, 2 denotes a stirring screw and a developing screw that are stirring means for stirring the developer in the developing device 1, and 3 denotes a developing device 1. A sub-toner container 4 stores toner to be replenished, 4 is a replenishing screw which is a first replenishing means for discharging the toner from the sub-toner container 3 and replenishing the developing device 1, and 5 stores toner to be replenished to the sub-toner container 3. A main toner container 6 is a stirring member as second supply means for discharging toner from the main toner container 5 and replenishing it to the sub toner container 3, and 7 is a rotation driving means capable of transmitting drive to the supply screw 4 and the stirring member 6. A motor 8 is a drive gear train which is a drive transmission means capable of transmitting the rotation of the motor 7 to the replenishing screw 4 and the stirring member 6, and 9 is a control means for controlling the rotation and stop of the motor.

  In the above configuration, when the motor 7 rotates in the direction A in the figure, the replenishing screw 4 and the stirring member 6 rotate at the same time, and the motor 7 stops and stops at the same time. That is, unlike the conventional example, the drive gear train 8 does not have a lever switching mechanism, a speed change mechanism, or a clutch mechanism, so that the rotational speeds of the motor 7, the replenishing screw 4, and the stirring means 6 are always proportional. Yes.

  In this case, unlike the conventional example, it is impossible to rotate the replenishing screw 4 with the stirring means 6 stopped, or to rotate the stirring means 6 with the replenishing screw 4 stopped. The stirring means 6 can always only be rotated and stopped at the same time. Therefore, if the angle at which the stirring means 6 rotates while the replenishing screw 4 rotates once is A ° (the constant A is determined from the gear ratio of the drive gear train), the sub-toner container when the replenishing screw 4 rotates 360 °. From the amount of toner replenished from 3 to the developing device 1: Xg, the average value of the amount replenished from the main toner container 5 to the sub toner container 4 when the stirring means 6 is rotated by A °: Yg is sufficiently large. The gear ratio of the drive gear train 8, the shape of the stirring member 6, the pitch of the replenishing screw 4, the size of the supply port from the main toner container 5 to the sub toner container 3, and the like are set.

  Hereinafter, a toner replenishment sequence with the above configuration will be described.

  The toner in the main toner container 5 is conveyed to the sub toner container 3 by driving the stirring member 6. In order to stably supply toner, the supply screw unit 4 and the sub toner container 3 are always required to secure a toner amount. Therefore, the toner consumption is predicted by a video count, which will be described later, and the motor 7 is turned on to drive the supply screw 4 so as to supply toner to the developing device 1 by the amount consumed in image formation. Since the replenishing screw 4 and the agitating member 6 rotate and stop simultaneously, when toner is replenished to the developing device 1, toner is replenished to the sub toner container 3 from the main toner container 5.

  The on-time of the motor 7 is set in units of blocks. That is, the amount of toner to be replenished in the process of continuously driving the replenishment screw 4 for a certain fixed time (for example, 250 msec) is defined as one block, and the amount of consumed toner is converted into the number of blocks to obtain the continuous drive time. Based on this time, the motor 7 is turned on to convey the toner from the sub-toner container 3 to the developing device 1.

  Here, the timing at which the replenishment screw 4 can rotate is limited to the time when the developing screw 2 of the developing device 1 is rotating, as in the conventional example. The control means 9 is set so that the developing screw 2 stops after the replenishment screw 4 stops rotating.

  FIG. 2 shows a normal replenishment timing chart in the case of replenishing 4 blocks to Y by color printing. The number of replenishment blocks is calculated from the video count value at the timing of writing the first color (Y) image. Based on the calculated number of supply blocks, the supply screw 4 is driven to convey the toner to the developing device 1. At this time, the on-time of the motor 7 is controlled so as to be within the time during which each color developer is being driven (during image formation). Here, an example of one color is given. However, when toner supply of a plurality of colors is performed, control is performed in accordance with the image start timing independently for each color as shown in FIG.

  The video count is usually just before the laser recording unit of the image forming apparatus, the image signal value that drives the laser is added for each color over the entire image, and the toner amount used for actual image formation is calculated from the added value by calculation. To determine the next replenishment amount. Accordingly, the video count value of the previous image is reflected in the number of toner supply blocks at the time of the next image formation. FIG. 3 shows an example of a table representing the relationship between the video count value per color for one A4, 600 dpi image and the number of supply blocks for the next image formation in this embodiment.

  As shown in the “replenishment rate” in the table, after forming an image with a high image duty and a large amount of toner consumption, instead of replenishing the consumed toner 100%, the next replenishment amount is set to a small value once. A large amount of toner is replenished to prevent the T / C ratio from becoming unstable. An actual video count value is acquired at the start of image formation, and the number of supply blocks is determined by linear interpolation of the values in this table.

  FIG. 11 shows a flowchart of the supply block number determination and the normal supply sequence based on the video count.

  At the start of image formation, the video count value of the previous image is acquired (S1101), and based on this, the number of supply blocks and the remaining count VC1 indicating the fraction less than one block are calculated (S1102). If B is the number of blocks that can be replenished at one time, the entire amount is replenished (S1104).

  On the other hand, if B is larger than the upper limit number of blocks that can be replenished in one image formation, only the replenishable amount is replenished, and the amount that could not be replenished is converted back to a video count and added to the remaining count VC1. . The remaining count VC1 is added to the video count acquisition value at the next image formation to be reflected in the correction result.

  Next, the remaining toner detection control and the recovery sequence will be described.

The presence or absence of toner is detected by using a toner sensor 406 attached to the sub toner container 3. If a large amount of toner remains in the main toner container 5 at the time of detecting the absence of toner, the user's satisfaction is impaired. Therefore, it is necessary to reduce the remaining amount of toner in the main toner container 5 as much as possible when determining the absence of toner. On the other hand, in order to stabilize the replenishment amount to the developing device 1, it is necessary to control the amount of toner in the sub toner container 3 to be a certain amount or more. Therefore, the toner remaining amount detection control and recovery sequence are executed as follows.
(1) Detection of remaining amount during installation When the user does not have toner in the sub-toner container 3 or the replenishment screw 4 and the user sets the main toner container 5 in the main body, the toner is brought into the sub-toner container 3 and a partial replenishment screw by the weight of the toner. 4 is filled.

The ratio at which the toner is filled in the sub-toner container 3 and its lower part varies depending on the state of the toner in the main toner container 5. For example, when the main toner container 5 is vibrated and left for a long time, the toner hardly falls. On the other hand, when the toner is sufficiently loosened, the toner may be filled up to the replenishing screw 4 just by being set. Thus, if the toner filling ratio at the time of installation is different, there is a concern that the block replenishment amount after installation is not stable and the density fluctuation becomes large. In order to avoid this, residual toner detection control is performed at the time of installation, and when no toner is detected, a recovery sequence described later is performed.
(2) Remaining amount detection at power-on / main toner container cover opening / closing The presence / absence detection of the toner sensor 406 is performed by integrating a predetermined number of data. It takes time to confirm. Therefore, if there is no toner before the power is turned off or before the cover is opened, the recovery sequence is executed assuming that no toner is present when the power is turned on or when the cover is closed.
(3) Remaining amount detection during image formation When no toner is detected during image formation, an upper module (not shown) is notified of the absence of toner, and the upper module continues the image forming operation only for the pages that have already started the paper feeding operation. Control is performed so as not to feed paper thereafter. If the image forming operation is performed after the detection of the absence of toner due to the above operation, toner replenishment may be required. In that case, the replenishment is continued with the toner remaining in the sub-toner container 3 and the replenishment screw 4 portion. After completing the operation, execute the recovery sequence.

  In the recovery sequence, the stirring member 6 of the main toner container 5 is driven for a time corresponding to one block, and the toner remaining in the main toner container 5 is supplied to the sub toner container 3. If the toner sensor 406 still detects the absence of toner after driving a predetermined number of blocks (eg, 4 blocks), it is determined that the main toner container 5 is empty, and the “no toner state” is determined.

  When the stirring member 6 is rotated in order to transport the toner in the main toner container 5 to the sub toner container 3 in the recovery sequence, the replenishing screw 4 and the stirring means 6 are always rotated and stopped simultaneously by driving the motor 7. Therefore, the toner remaining in the sub-toner container 3 is added to the developing device 1 through the supply screw 4 by an amount corresponding to the driving time.

  To correct the T / C ratio error and density error due to this extra toner addition, the amount of toner that was unscheduled and transferred into the developing device 1 when the recovery sequence was performed is stored, and the recovery sequence ends. At the time of toner replenishment in a normal sequence performed in subsequent image formation, the toner density in the developing device is restored to a predetermined density by feeding back to the toner amount to be replenished.

  FIG. 6 is a flowchart for explaining toner amount error detection during the recovery sequence. As described above, in the recovery sequence, the motor 7 is turned on for a time corresponding to one block and the toner is replenished from the main toner container 5 to the sub toner container 3, so that the amount corresponding to one block is increased every time the drive is driven. Toner enters the developing device 1. Therefore, by counting the number of blocks VAL_FORCE driven in the recovery sequence (S602) and backing up, the amount of extra toner supplied can be determined.

  When the output of the toner sensor 406 changes to the “toner present” state during the recovery sequence (S603), it is assumed that the toner still remains in the main toner container 5 (S604), and the recovery sequence ends.

  On the other hand, if there is no change from “no toner” even after driving a predetermined number of drive motors, “no toner” detection is determined (S606). In both cases, after the recovery sequence is completed, the amount of extra replenished toner is held in the number of blocks VAL_FORCE.

  In order to correct the amount and replenish the toner in the subsequent processing, after the recovery sequence is completed, for example, the video count number corresponding to the recovery correction block number VAL_FORCE is added to the remaining count VC1 of the video count value described in FIG. (S607). As a result, at the time of the next image formation, the count result can be reflected in the normal replenishment sequence shown in FIG. 11, and at the same time, the toner density in the developing device can be recovered without changing the density by reflecting the replenishment amount at a time. be able to.

  Here, the toner sensor 406 of the sub-toner container 3 is installed in the middle of the sub-toner container 3, and when the sensor output changes from the toner present state to the toner-free state, a certain amount of toner is still in the sub toner container 3. Remaining. For example, in this embodiment, the sub-toner container accommodates 18 blocks of toner on the sensor and 12 blocks of toner under the sensor.

<Embodiment 2>
As a means for correcting the toner density, in addition to the above video count, in case there is an error in the replenishment amount, the paper interval when the number of sheets exceeds the number during continuous image formation or the video count integration number is a constant value. It is considered to perform automatic density correction control by patch detection (hereinafter referred to as patch detection ATR) to correct the error when the value exceeds. Here, the patch detection ATR forms a solid image of a predetermined density for each color on the transfer belt of the image forming apparatus, and detects the density of the solid image formed by the reflection type density sensor provided facing the belt. In this method, the toner replenishment amount is controlled so as to fill in the error by comparing with the predetermined density of the wrinkles originally formed.

  FIG. 4 shows a flowchart of processing for converting the density difference into the number of ATR correction blocks (VAL_ATR) in order to perform block replenishment based on the result of the patch detection ATR.

  As described above, the density D of the patch image is measured by the density sensor (S402), and the T / C ratio change amount ΔD is obtained from the density error from the predetermined density (S403). When ΔD is larger than a predetermined adjustable range (S404), it is determined that correction cannot be made by adjustment, and an ATR error is determined (S405). When ΔD is within the adjustable range, the patch density D is multiplied by a conversion coefficient for converting ΔD into the number of toner replenishment blocks depending on whether the patch density D is less than or equal to the predetermined value (S406 to S412). The ATR correction block number VAL_ATR is calculated (S413).

  FIG. 5 shows a flowchart of processing for determining the number of blocks to be actually replenished from the video count result and the number of ATR correction blocks.

  In FIG. 5, the limit of the number of blocks that can be increased or decreased from the basic supply block number B obtained by video count in one supply is limited (in this example, limited to 1 block), and the ATR correction block number VAL_ATR is set to a value other than 0. If it is set (S503), correction is performed for each block (S504 to S507) regardless of whether the patch is dark or light. When the number of ATR correction blocks VAL_ATR is larger than the number of blocks that can be added at one time (S508), the number of remaining blocks (B-upper limit value) is stored and stored in VAL_ATR (S511), and the next time toner is replenished. Replenish as above.

In the system that performs this correction, instead of the process in which VAL_FORCE is converted into a video count value and fed back in the first embodiment, the above-mentioned forced supply correction block number VAL_FORCE is added to the ATR correction block number VAL_ATR in FIG.
By adding correction such as adding minutes, it is possible to reflect the density error generated in the recovery sequence little by little in the correction.

  In the first and second embodiments, the error caused by the recovery sequence is fed back to the number of toner blocks to be replenished next time. In addition to this, for example, the total number of replenishment blocks reflecting only the ATR correction is calculated in FIG. In addition, various implementation methods are conceivable for feedback of the forced supply block number VAL_FORCE, such as changing the toner supply speed according to the difference between the total supply block number and the forced supply block number VAL_FORCE to reduce the excess supply amount.

<Embodiment 3>
In the above embodiment, when the toner sensor 406 detects the absence of toner for the first time after the toner is present, it is considered that 12 blocks of toner remain in the sub toner container 3. If the replenishment screw 4 is driven by the number of remaining toner blocks in the sub-toner container 3, if the main toner container 5 is really empty, the toner in the sub-toner container 3 may be empty. In this case, since the relationship between the number of blocks and the replenished toner amount is not guaranteed, the number of blocks to be replenished in the image formation and forced replenishment sequence after the determination of no toner can be controlled so as not to exceed this remaining toner amount. desirable.

  FIG. 7 shows a flowchart for calculating the number of forced replenishment blocks VAL_FORCE when there is no toner in the remaining amount detection during image formation and image formation is continued thereafter.

  After the toner is determined (S701), an image is formed and the toner is consumed, and when the normal replenishment sequence is operated with the remaining toner in the sub toner container 3 (S704), the VAL_FORCE count is started from the time when the toner is determined, and thereafter The number of replenished blocks is counted (S705).

After the completion of image formation, the forced replenishment sequence is entered continuously, the number of blocks in the forced replenishment sequence is added to the number of blocks used in image formation (S708), and thereafter the number of forced replenishment blocks VAL_FORCE is set as in the first embodiment. Number of ATR correction blocks VAL_ATR
Is added to and backed up (S709 to S713). By utilizing this, by adjusting the supply amount of the normal supply sequence at the time of subsequent image formation, it becomes possible to adjust the toner amount more accurately.

It is the figure which showed the mechanical structure of Embodiment 1 of this invention. It is a normal replenishment sequence timing diagram. It is a figure which shows the relationship between a video count and the block supply frequency | count. It is a flowchart of a patch detection ATR result-supply block number conversion process. It is a supply block number determination process flowchart of the normal supply sequence of Embodiment 2 of this invention. 6 is an error toner amount calculation flowchart in a forced supply sequence. 12 is an error toner amount calculation flowchart according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a conventional developing device and toner replenishing means. 1 is a cross-sectional view of a quadruple tandem image forming apparatus. This is the relationship between the developing device drive time and the toner replenishment time. It is a replenishment block number determination process flowchart of the normal replenishment sequence of Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developer 2 Stir development screw 3 Sub-toner container 4 Replenishment screw 5 Main toner container 6 Stirring member 7 Motor 8 Drive gear train 9 Control means

Claims (2)

A developer,
A sub-toner container for storing toner to be replenished to the developer;
First supply means for discharging toner from the sub-toner container and supplying the developer to the developer;
A main toner container for storing toner to be replenished to the sub-toner container;
Second supply means for discharging toner from the main toner container and supplying the toner to the sub toner container;
A rotation drive means serving as a drive source for the first supply means and the second supply means;
Drive transmission means configured such that the rotational speeds of the rotational drive means, the first supply means, and the second supply means are always in a substantially proportional relationship;
Control means for rotating and stopping the rotation driving means;
Measuring means for measuring the remaining amount of toner in the sub-toner container;
In the image forming apparatus provided with a control unit that performs a recovery sequence when the toner remaining amount measuring unit of the sub toner container measures the absence of toner,
A toner replenishment amount adjusting unit that measures a toner amount replenished to the developing device during the recovery sequence and corrects the measured toner amount based on a toner replenishment amount during image formation after the recovery sequence; An image forming apparatus.   The image forming apparatus according to claim 1, wherein the toner replenishing amount adjusting unit divides and reduces the toner replenishing amount that needs to be reduced when the image is formed at least twice.

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