JP2015052668A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of reduce a time until a development unit is replenished with a necessary amount of toner from a storage container even when the storage container is changed with another one.SOLUTION: An image formation device 200 comprises a development unit 5a, an installation part in which a toner bottle 20a for replenishing the development unit 5a with a toner is installed, a toner bottle detection sensor 54 for detecting installation of the toner bottle 20a, a drive motor 60 for rotating the toner bottle 20a with a drive force corresponding to a current, a rotation detection sensor 58 for detecting information about the rotation of the toner bottle 20a, and a CPU 70 for controlling a current value supplied to the drive motor 60. If the current supplied to the drive motor 60 before the toner bottle 20a is changed is less than a prescribed value, the CPU 70 changes the current to be supplied to the drive motor 60 to a higher current value than the prescribed value.

Description

  The present invention relates to an image forming apparatus to which a storage container in which toner is stored is mounted.

  An electrophotographic image forming apparatus forms a toner image by developing an electrostatic latent image formed on a photoreceptor using a developer (hereinafter referred to as “toner”) in a developing device. Since the amount of toner that can be accumulated in the developing device is limited, the toner is appropriately replenished to the developing device from a container that is detachable from the main body of the image forming apparatus.

  As a container for containing toner, a rotating part that is driven to rotate, a pump part that changes the internal pressure of the containing part in order to discharge the toner from the containing part that contains toner, and a rotational movement of the rotating part to an expansion and contraction movement of the pump part The thing provided with the conversion part to convert is proposed (patent document 1). The container discharges the toner in the container by expanding and contracting the pump unit according to the rotation of the container. That is, in the storage container, the air sucked from the discharge port as the pump part extends releases the toner in the storage part, and then the pump part compresses so that the air in the storage container covers the discharge port. Push the toner out from the outlet.

JP 2010-256893 A

  However, when the container (toner bottle) is replaced, the rotation of the toner bottle is caused by the difference between the driving torque for rotating the toner bottle before replacement and the driving torque for rotating the toner bottle after replacement. The speed may decrease. This is because the drive torque is controlled according to the amount of toner in the toner bottle. For example, when the toner bottle is replaced, the driving torque set in a state where the toner amount in the toner bottle is decreased is smaller than the driving torque necessary for rotating the replaced toner bottle. Therefore, even if the toner bottle is replaced, even if the toner bottle is rotated using the driving torque set before the replacement, the replaced toner bottle can be rotated at the target rotation speed. Can not. That is, there is a possibility that the time until the required amount of toner is supplied to the developing device after the toner bottle replacement is increased.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can shorten the time required to replenish a necessary amount of toner from a container even when the container is replaced.

  In order to solve the above-mentioned problem, the image forming apparatus according to claim 1 is equipped with a developing unit that develops the electrostatic latent image formed on the photoreceptor using toner, and a storage container that stores the toner. A mounting unit; a mounting detection unit configured to detect that the storage unit is mounted on the mounting unit; and a storage unit mounted on the mounting unit for supplying toner from the storage container to the developing unit. The rotation speed of the receiving container based on the rotation information detected by the rotation detecting means, the rotation detecting means for detecting the rotation information of the receiving container rotated by the driving means, Control means for controlling the current supplied to the drive means so as to have a predetermined speed, and the control means is configured to remove the storage container attached to the attachment portion and then to attach the attachment detection means. In If it is detected that the storage container is attached to the attachment part, and if the current supplied to the drive means by the control means before the storage container is removed from the attachment part is less than a predetermined value, The current to be supplied to the driving means is changed to a current higher than the predetermined value.

  According to the present invention, even when the storage container is replaced, it is possible to shorten the time until the necessary amount of toner is supplied from the storage container.

1 is a schematic sectional view of an image forming apparatus. It is a principal part schematic diagram of a bottle mounting part. FIG. 3 is a schematic view of a main part of a toner bottle. 3 is a block diagram illustrating a control configuration of a toner supply system. FIG. 6 is a flowchart illustrating a procedure of rotation speed adjustment processing after toner bottle replacement. FIG. 3 is a schematic view of a main part showing a positional relationship between a toner bottle and a rotation detection sensor. 6 is a timing chart of toner supply processing.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  FIG. 1 is a schematic sectional view of the image forming apparatus.

  In FIG. 1, an image forming apparatus 200 is an electrophotographic image forming apparatus. For example, an intermediate transfer tandem in which image forming units 100Y, 100M, 100C, and 100Bk corresponding to four colors are arranged in parallel in a substantially horizontal direction. This is an image forming apparatus of the type.

  The image forming units 100Y to 100Bk include photosensitive drums 1a, 1b, 1c, and 1d, charging devices 2a, 2b, 2c, and 2d, exposure devices 3a, 3b, 3c, and 3d, developing devices 5a, 5b, 5c, and 5d, respectively. Transfer rollers 4a, 4b, 4c and 4d are provided. Here, the photosensitive drums 1a, 1b, 1c, and 1d function as photosensitive members. Further, the image forming units 100Y to 100Bk are provided with photoreceptor cleaners 6a, 6b, 6c, and 6d, respectively.

  An intermediate transfer belt 7 is disposed above the image forming unit. The intermediate transfer belt 7 is an endless belt and rotates in the direction of arrow A. The intermediate transfer belt 7 is rotatably stretched by a secondary transfer inner roller 8 that also serves as a drive roller, a tension roller 9, a secondary transfer upstream roller 10, and a secondary transfer downstream roller 11. Above the intermediate transfer belt 7, toner bottles 20 a, 20 b, 20 c, and 20 d as storage containers for supplying toner as a developer to the developing devices 5 a to 5 d of the image forming unit are disposed.

  Below the image forming units 100Y to 100Bk, two-stage recording material storages 16a and 16b are provided, and the recording material storages 16a and 16b store sheets S as recording materials, respectively. . A transport path R1 is provided from the recording material storages 16a and 16b through the fixing device 19 to the paper discharge roller 22. Paper feed rollers 17a and 17b and a registration roller (registration roller) 18 are arranged in the transport path R1. The fixing device 19 is provided with a heater serving as a heat source (not shown).

  In the image forming apparatus 200 having such a configuration, after the photosensitive drums 1a to 1d of the image forming units 100Y to 100Bk start to rotate, the charging devices 2a to 2d uniformly distribute the surfaces of the corresponding photosensitive drums 1a to 1d, respectively. Is charged. Next, the exposure devices 3a to 3d irradiate the photosensitive drums 1a to 1d with laser beams based on the image signals, so that the exposure devices 3a to 3d form electrostatic latent images on the photosensitive drums 1a to 1d. Corresponding developing devices 5a to 5d supply toner to the electrostatic latent images formed on the photosensitive drums 1a to 1d, respectively, and are visualized as toner images. The toner images formed on the respective photosensitive drums 1a to 1d are subjected to intermediate transfer so that the corresponding primary transfer portions 15a to 15d are given a transfer bias (primary transfer bias) and are sequentially superimposed on the upstream color toner images. Transferred onto the belt 7. As a result, a full-color image is carried on the intermediate transfer belt 7. Here, the primary transfer portions 15a, 15b, 15c, and 15d are regions formed by the photosensitive drums 1a, 1b, 1c, and 1d and the primary transfer rollers 4a, 4b, 4c, and 4d of each image forming portion.

  The toner remaining on the photosensitive drums 1a to 1d without being transferred from the photosensitive drums 1a to 1d to the intermediate transfer belt 7 is removed by the photosensitive member cleaners 6a to 6d. When the toner amount in the developing devices 5a to 5d decreases, the toner is replenished from the corresponding toner bottles 20a to 20d. A specific toner supply method will be described later.

  The sheet S is conveyed to the secondary transfer unit 24 at the same timing that the image formed on the intermediate transfer belt 7 is conveyed to the secondary transfer unit 24. Here, the secondary transfer portion 24 is an area formed by the secondary transfer inner roller 8 and the secondary transfer outer roller 13 of the intermediate transfer belt 7. The sheet S sent out by the sheet feeding roller 17 is conveyed toward the registration roller 18 through the conveyance path R1, and then subjected to the skew correction and adjustment of the conveyance timing in the registration roller 18, and then the secondary transfer. It is conveyed to the section 24. A transfer bias (secondary transfer bias) is applied to the sheet S conveyed to the secondary transfer unit 24 via the secondary transfer inner roller 8 or the secondary transfer outer roller 13, so that a color image on the intermediate transfer belt 7 is obtained. Is transferred to the paper S. The toner remaining on the intermediate transfer belt 7 without being transferred from the intermediate transfer belt 7 to the paper S is removed by the blade 12 a of the transfer cleaner device 12.

  The sheet S on which the color image has been transferred is carried into the fixing device 19 and given a predetermined pressure and heat amount while passing through a fixing nip formed by two opposing rollers of the fixing device 19. The upper color image is melted and fixed on the paper S and fixed. The paper S on which the color image has been fixed is discharged onto a paper discharge tray 23 via a paper discharge roller 22.

  Next, the developer supply mechanism (hereinafter referred to as “toner supply mechanism”) in the image forming apparatus 200 of FIG. 1 will be described. The toner replenishment mechanism replenishes the developing devices 5a to 5d with toner as a developer. Four toner replenishing mechanisms are provided to correspond to the image forming units 100Y to 100Bk, respectively, but all have the same configuration. Accordingly, the structure, operation, and the like will be described in detail below using a toner supply mechanism corresponding to the image forming unit 100Y as an example.

  The toner replenishing mechanism includes a bottle mounting portion provided in the image forming apparatus 200, and a drive motor as a rotation drive source of the toner bottle mounted on the bottle mounting portion.

  2A and 2B are schematic views of a main part of the bottle mounting portion in the image forming apparatus 200 of FIG. 1, in which FIG. 2A is a front view and FIG. 2B is a perspective view with a part cut away.

  In FIG. 2, the bottle mounting portion includes a mounting portion main body 30 in which a semi-cylindrical recess into which a substantially cylindrical toner bottle is fitted and a substantially circular through-hole into which one end of the toner bottle is fitted, and the mounting It is mainly composed of a drive gear 59 provided in a through hole portion of the part main body 30. When the toner bottle is mounted along the arrow B, the drive gear 59 meshes with the driven gear of the toner bottle and transmits the driving force to the toner bottle. The semi-cylindrical concave portion of the mounting portion main body 30 has a step-shaped rotation restricting portion that fits with a protruding portion of a cap portion, which will be described later, of the toner bottle along the length direction thereof and restricts the rotation of the cap portion. 31 is provided. An axial direction regulating member 33 is provided at the bottom of one end of the rotation regulating unit 31, and the axial direction regulating member 33 regulates movement of the mounted toner bottle in the rotational axis direction.

  3A and 3B are schematic views of a main part of the toner bottle mounted on the bottle mounting portion of FIG. 2, in which FIG. 3A is an external view, and FIG. 3B is a maximum extension of the toner bottle pump portion. FIG. FIG. 3C is a diagram illustrating a state where the pump portion of the toner bottle is maximally contracted.

  3A to 3C, the toner bottle 20a discharges the toner toward the developing device in synchronization with the rotation operation. The toner bottle 20a includes a toner container 41 that stores toner, a driving force input unit 44 that receives rotational driving force, a body 45 that is fixed to the driving input unit 44, a discharge unit 47 that discharges toner, and a discharge unit 47. It has a pump unit 50 for controlling the internal pressure. The toner bottle 20 a has a reciprocating member 51 connected to the pump unit 50. That is, the toner bottle 20a includes a toner container 41, a driving force input unit 44, a body 45 fixed to the driving input unit 44, a toner discharge unit 47, a pump unit 50 that controls the pressure in the discharge unit 47, and It is mainly composed of a reciprocating member 51 connected to the pump unit 50. A part of the body part 45, the discharge part 47, the pump part 50, and the reciprocating member 51 are covered with a cap part 52.

  A driven gear 43 is formed in the driving force input unit 44 along the circumferential direction thereof. The body portion 45 includes a small diameter portion 45a and a large diameter portion 45b. The driven gear 43 meshes with a drive gear 59 of a toner bottle drive motor (hereinafter simply referred to as “drive motor”) 60 that drives the toner bottle 20a. A rotational driving force is input to the driving force input unit 44 from the driving motor 60 via the driving gear 59 and the driven gear 43.

  On the inner wall surface of the toner storage unit 41, a conveyance unit 42 protruding in a spiral shape is provided. Accordingly, the toner in the toner storage unit 41 is conveyed from the toner storage unit 41 to the discharge unit 47 in accordance with the rotation of the toner storage unit 41.

  The large-diameter portion 45b of the body portion 45 is provided with a detected portion 55 including a convex portion 55a and a flat portion 55b along the circumferential direction, and the phase is set so as to face the detected portion 55. A rotation detection sensor 58 as a detecting means is arranged. In addition, the small-diameter portion 45a of the body portion 45 is provided with a cam groove 46 that is curved at a predetermined cycle over the entire circumference in the circumferential direction. The discharge portion 47 communicates with the toner storage portion 41 and the internal space. Furthermore, the internal space of the discharge part 47 and the pump part 50 are also communicated.

  The discharge portion 47 is provided with a toner discharge port 48. The diameter of the discharge port 48 is, for example, about 2 [mm]. As the toner bottle 20a rotates, the toner in the toner storage unit is transported to the discharge unit 47 by the transport unit 42, temporarily stays in the discharge unit 47, and then the discharge port 48 is opened by the action of the pump unit 50. Then, it is discharged toward a developing device (not shown).

  The discharge part 47 and the pump part 50 are substantially cylindrical. The pump unit 50 is a bellows-like pump in which a plurality of mountain folds and valley folds are alternately formed, and is made of resin. A reciprocating member 51 is connected to the tip of the pump unit 50, and an arm of the reciprocating member 51 extends to the cam groove 46. Two arms of the reciprocating member 51 are provided with the central axis of the pump unit 50 symmetrical. A claw portion is formed on the arm of the reciprocating member 51, and this claw portion is engaged with the cam groove 46.

  The reciprocating member 51 and the cam groove 46 with which the reciprocating member 51 engages constitute a driving force conversion mechanism that converts a part of the rotational driving force input to the toner bottle 20a into a reciprocating driving force. . That is, the body 45 is rotated together with the toner container 41 by the rotational driving force input from the drive motor 60 to the toner bottle 20a. As the body 45 rotates, the reciprocating member 51 engaged with the cam groove 46 repeats linear motion reciprocating in the direction of arrow C in FIG. When the reciprocating member 51 reciprocates, the tip of the pump member 50 and the end of the fixed pump unit 50 are also reciprocated in the direction of arrow C, whereby the pump unit 50 expands and contracts (FIG. 3 (B)). (FIG. 3C) is repeated.

  The pump unit 50 functions as an intake / exhaust mechanism that alternately performs an intake operation and an exhaust operation via a toner discharge port 48. In addition, by the intake / exhaust by the pump unit 50, an airflow that flows from the discharge port 48 toward the inside of the toner bottle 20 a and an airflow that flows from the inside of the toner bottle 20 a through the discharge port 48 to the outside of the discharge unit 47 are alternately formed. Therefore, the pump unit 50 is also an airflow generation mechanism.

  While the toner bottle 20a rotates once, the reciprocating member 51 reciprocates twice in the direction of arrow C, for example, and the pump unit 50 repeats expansion and contraction, for example, twice. As a result, toner is supplied to a developing device (not shown). The amount of toner replenished from the toner bottle 20a to the developing device is determined by the number of expansion and contraction operations of the pump unit 50. After the number of expansion and contraction operations (necessary number) of the pump unit 50 is determined according to the amount of toner to be supplied to the developing device, the number of expansion and contraction operations of the pump unit 50 detected by the rotation detection sensor 58. Until the required number of times is reached, the toner bottle 20a is rotated.

  Further, the outer peripheral surface of the cap portion 52 has a protruding portion that partially protrudes, and this protruding portion is a rotation restricting portion provided in the mounting portion main body 30 of the bottle mounting portion for mounting the toner bottle 20a. 31. Therefore, the cap portion 52 of the toner bottle 20a does not rotate. The cap unit 52 is provided with a toner bottle detection flag 53. The toner bottle detection flag 53 is detected when the toner bottle 20a is mounted on the bottle mounting portion of the image forming apparatus 200 in the image forming apparatus 200. A detection sensor 54 is provided. The toner bottle detection sensor 54 functions as a mounting detection unit. The discharge part 47 is connected to the body part 45 via a sliding part, and the rotation is restricted by a rotation restriction member (not shown). Therefore, the discharge part 47 and the pump part 50 have a structure that does not rotate even when the body part 45 rotates.

  Next, the control configuration of the toner replenishment system in the image forming apparatus 200 having such a configuration will be described.

  FIG. 4 is a block diagram showing a control configuration of the toner supply system in the image forming apparatus 200 of FIG.

  In FIG. 4, a control board 300 that controls the entire image forming apparatus 200 includes a CPU 70 as a central processing unit. The CPU 70 is connected to a RAM 73, a ROM 74, and an ASIC 72, which are nonvolatile memories. The ASIC 72 is connected to the rotation detection sensor 58 via a sensor drive circuit 65 and a sensor output detection circuit 66, respectively. The ASIC 72 is connected to a drive motor 60 that drives the toner bottle 20 a via a motor drive path 63, and is connected to the toner bottle detection sensor 54 via a sensor detection circuit 67. The toner bottle detection sensor 54 is toner bottle attachment detection means.

  The ASIC 72 is an integrated circuit in which functions related to the toner replenishing operation are implemented as hardware, and reduces the arithmetic processing of the CPU 70. The motor drive circuit 63 receives the motor control signal from the ASIC 72 and controls the drive speed of the drive motor 60 that drives the toner bottle in accordance with the received motor control signal. The motor control signal is, for example, a PWM (Pulse Width Modulation) signal. This PWM signal is a signal indicating the ratio of time during which current is supplied to the drive motor 60 per predetermined time. When the DUTY ratio of the PWM signal increases, the time during which current is supplied to the drive motor 60 in a predetermined time increases. On the other hand, when the DUTY ratio of the PWM signal decreases, the time during which current is supplied to the drive motor 60 in a predetermined time decreases. A DC motor (brush motor) is used as the drive motor 60. For this reason, even if a current is supplied to the drive motor 60 based on a predetermined DUTY ratio, the rotational speed of the drive motor 60 decreases if the weight of the toner bottle 20a increases.

  The rotation detection sensor 58 is driven by the sensor drive circuit 65, and when the toner bottle 20a is rotated while the toner bottle 20a is mounted on the image forming apparatus 200, the output changes according to the state of the rotation detection flag 57. It is configured to do. The ASIC 72 can detect the toner supply operation by monitoring the output of the rotation detection sensor 58 through the sensor output detection circuit 66. The ASIC 72 has a timer function for measuring the time during which the rotation detection sensor 58 outputs a predetermined output (here, Low) during the toner replenishment operation, and the measurement result (the rotation detection sensor 58 outputs a predetermined output signal). The output time) is stored in the nonvolatile RAM 73. The ASIC 72 performs feedback control of the DUTY ratio of the PWM signal so that the time during which the rotation detection sensor 58 outputs a predetermined output signal becomes the target time. A method for feedback controlling the rotation speed of the toner bottle 20a based on the output signal of the rotation detection sensor 58 will be described later. The example in which the toner replenishment control is executed using the ASIC 72 has been described above. However, the toner replenishment control can be executed similarly using only the CPU 70.

  Next, the rotation speed adjustment processing after the toner bottle replacement using the image forming apparatus of FIG. 1 will be described in detail with reference to the drawings.

  FIG. 5 is a flowchart showing the procedure of the rotation speed adjustment process after the toner bottle replacement. The rotation speed adjustment process after the toner bottle replacement is executed by the CPU 70 (or ASIC 72) provided on the control board 300 of the image forming apparatus 200 reading out the rotation speed adjustment process program after the toner bottle replacement stored in the ROM 74. Is done.

  In FIG. 5, when the rotation speed adjustment process after the toner bottle replacement is started, the CPU 70 first determines whether or not the toner bottle has been replaced (step S501). The CPU 70 determines that the toner bottle 20a has been replaced when the detection signal of the toner bottle detection sensor 54 that detects the toner bottle detection flag 53 changes from “flag non-detection” to “flag detection”.

  As a result of the determination in step S501, when the toner bottle 20a is replaced (“YES” in step S501), the CPU 70 determines whether or not the current value supplied to the drive motor 60 before the toner bottle replacement is equal to or greater than a predetermined value. Is determined. That is, the CPU 70 determines whether or not the DUTY ratio of the PWM signal input to the drive motor 60 before the toner bottle 20a is replaced is greater than or equal to a predetermined value (step S502). The DUTY ratio (current amount) of the PWM signal before the toner bottle replacement is stored in, for example, the nonvolatile RAM 73 and can be confirmed by the CPU 70.

  Next, when the DUTY ratio of the PWM signal before bottle replacement is equal to or greater than a predetermined value (“YES” in step S502), the CPU 70 determines that the driving torque of the toner bottle before bottle replacement is large. Then, the CPU 70 sets the DUTY ratio of the PWM signal before the bottle replacement as it is as the DUTY ratio of the PWM signal after the bottle replacement. That is, the DUTY ratio is not changed (step S503).

  On the other hand, if the DUTY ratio of the PWM signal before bottle replacement is less than the predetermined value (“NO” in step S502), the CPU 70 determines that the driving torque of the toner bottle before bottle replacement was small. Then, the CPU 70 sets the DUTY ratio of the PWM signal having a longer current supply time than the DUTY ratio of the PWM signal before bottle replacement as the DUTY ratio of the PWM signal after bottle replacement (step S508). The DUTY ratio of the PWM signal, in which the current supply time is longer than the DUTY ratio of the PWM signal before the bottle replacement, is a toner bottle 20a within a predetermined time even when the load on the toner bottle 20a is maximum in manufacturing. Is set so as to obtain a driving torque capable of rotating once. The DUTY ratio (predetermined DUTY ratio) of the PWM signal whose current supply time is longer than the DUTY ratio of the PWM signal before the bottle replacement is stored in the nonvolatile RAM 73 in advance.

  Next, after the ASIC 72 sets a PWM signal having a predetermined DUTY ratio, the ASIC 72 waits until the drive motor 60 is driven at the drive timing of the toner bottle 20a, for example, the toner replenishment timing, and starts driving at this drive timing. (Step S504). Next, the ASIC 72 measures the time during which the rotation detection sensor 58 detects the rotation detection flag 57, that is, the time during which the rotation detection sensor 58 outputs the output “Low” (step S505), and the rotation speed of the toner bottle 20a. Ask for.

  Here, FIG. 6 is a main part schematic diagram showing the positional relationship between the toner bottle and the rotation detection sensor. FIG. 6A is a diagram illustrating a state in which the rotation detection sensor 58 detects the convex portion 55a of the detected portion of the toner bottle 20a. FIG. 6B is a diagram illustrating a state in which the rotation detection sensor 58 detects the flat portion 55b of the detected portion of the toner bottle 20a.

  6A and 6B, a rotation detection sensor 58 that detects rotation information of the toner bottle 20a is provided so as to face the detected portion 55 provided in the body 45 of the toner bottle 20a. The rotation detection sensor 58 detects the convex portion 55 a of the detected portion 55 via the rotation detection flag 57. As shown in FIGS. 6A and 6B, the rotation detection flag 57 is supported so as to be swingable in the directions of arrows R1 and R2. Further, the rotation detection flag 57 is in contact with the body 45 of the toner bottle 20a by its own weight. When the body 45 of the toner bottle 20a rotates, the rotation detection flag 57 is pushed up by the convex portion 55a, and the rotation detection flag 57 swings around the rotation shaft 49 in the direction of arrow R1 in FIG. . As shown in FIG. 6B, the rotation detection sensor 58 cannot detect the rotation detection flag 57 while the rotation detection flag 57 is in contact with the flat portion 55b. The rotation detection sensor 58 is an optical sensor having a light emitting unit and a light receiving unit, and when a light shielding object, for example, a rotation detection flag 57 exists between the light emitting unit and the light receiving unit (FIG. 6A), In this case, the output signal “Low” is output. On the other hand, if there is no light-shielding object, for example, the rotation detection flag 57 between the light emitting unit and the light receiving unit (FIG. 6B), the amount of light received by the light receiving unit is equal to or greater than a threshold value. Output signal “Hi” is output. That is, the output signal of the rotation detection sensor 58 changes from “Low” to “Hi” and from “Hi” to “Low” by detecting the detected portion.

  The convex portion 55a of the detected portion 55 is provided in synchronization with the timing at which the pump portion 50 contracts, that is, the timing at which the toner is discharged, and the convex portion 55a is detected and the toner is replenished toward the developing device. During this time, the output “Low” is output. The ASIC 72 stops the rotation drive of the drive motor 60 in response to the rotation detection sensor 58 outputting the output signal “Hi”.

  FIG. 7 is a timing chart of the toner supply process.

  In FIG. 7, the drive of the drive motor 60 is started, and the rotational speed stabilizes and reaches Vn at time t1. When the drive motor 60 is driven, the toner bottle 20a is rotated, and the rotation detection sensor 58 outputs “Low” at time t2 in synchronization with the timing at which toner supply from the toner bottle 20a toward the developing device is started. Is output. When the output of the rotation detection sensor 58 changes from “Hi” to “Low”, the ASIC 72 starts the counter and measures the time until time t3 when the output of the rotation detection sensor 58 changes to “Hi”. That is, the ASIC 72 counts the toner replenishment time. The ASIC 72 stops the drive motor 60 at time t4 after the rotation detection sensor 58 detects the output “Hi”. The ASIC 72 measures the time during which the rotation detection sensor 58 outputs the output “Low”, and detects the rotation speed of the toner bottle. As can be seen from FIG. 7, since the drive motor 60 is stopped after the replenishment of toner toward the developing device is completed, the toner bottle 20a is always stopped in the intake state.

  Returning to FIG. 5, after the time during which the rotation detection sensor 58 outputs the output “Low” is measured (step S 505), the ASIC 72 keeps the time during which the rotation detection sensor 58 outputs the output “Low” within a predetermined range. It is determined whether or not there is (step S506). Based on the time during which the rotation detection sensor 58 outputs “Low”, the rotation speed of the container 20a can be detected. Next, if the time during which the rotation detection sensor 58 has output the output signal “Low” is within a predetermined range (“YES” in step S506), the ASIC 72 determines the DUTY of the PWM signal set by the CPU 70 in step S503 or S508. Judge that the ratio is appropriate. Then, the ASIC 72 determines the DUTY ratio of the PWM signal as the DUTY ratio of the PWM signal to be input to the drive motor 60 in the next toner replenishment operation (step S507), and ends this process. Note that the predetermined range of time during which the output of the rotation detection sensor 58 is “Low” is appropriately determined depending on the amount of toner replenished to the developing device.

  On the other hand, if the time during which the rotation detection sensor 58 outputs the output signal “Low” is out of the predetermined range (“NO” in step S506), whether or not the time during which the output signal “Low” is output is longer than the predetermined range. Is determined (step S510). If the rotation speed of the toner bottle 20a does not reach the target speed, the amount of toner replenished from the toner bottle 20a to the developing device varies by one replenishment operation of the toner bottle 20a, and an image formed by the image forming apparatus. May not be the desired concentration. As a result of the determination in step S510, when the time when the output signal “Low” is output from the rotation detection sensor 58 is longer than the predetermined range (“YES” in step S510), the ASIC 72 has a low rotation speed of the toner bottle 20a. Judge. Then, the ASIC 72 increases the duty ratio of the PWM signal by a predetermined amount in order to increase the rotational speed of the drive motor 60 (step S511), and then returns the process to step S504.

  On the other hand, as a result of the determination in step S510, when the time when the output signal “Low” is output from the rotation detection sensor 58 is shorter than the predetermined range (“NO” in step S510), the ASIC 72 has the rotation speed of the toner bottle 20a. Judge that it is fast. Then, the ASIC 72 decreases the DUTY ratio of the PWM signal by a predetermined amount in order to decelerate the rotation speed of the drive motor 60 (step S512), and returns the process to step S504 as described above.

  The ASIC 72 performs feedback control of the DUTY ratio of the PWM signal so that the rotation speed of the toner bottle 20a becomes the target speed by repeating the operations in steps S504 to S512.

  If the result of the determination in step S501 is that the toner bottle 20a has not been replaced, the CPU 70 sets the DUTY ratio of the PWM signal before the bottle replacement as it is as the DUTY ratio of the PWM signal (step S509). That is, the CPU 70 does not change the rotation speed of the drive motor 60 unless the toner bottle 20a is replaced.

  According to the process of FIG. 5, when the storage container is mounted, if the current supplied to the drive means of the storage container by the control means before the storage container is removed from the mounting portion is less than a predetermined value, the drive means The current to be supplied is changed to a current higher than a predetermined value. That is, even after the toner bottle 20a is replaced, the rotation speed of the toner bottle 20a can be maintained at a predetermined speed or higher, so that a necessary amount of toner is supplied from the toner bottle 20a to the developing device immediately after the toner bottle 20a is replaced. Can be shortened.

  As a result, even if the driving torque for rotating the toner bottle varies with the replacement of the toner bottle, the rotation speed of the toner bottle becomes the target speed. Variation in density can be reduced.

5a to 5d Developing devices 20a to 20d Toner bottle 41 Toner accommodating portion 44 Driving force input portion 45 Trunk portion 47 Discharge portion 50 Pump portion 54 Toner bottle detection sensor 55 Detected portion 55a Convex portion 55b Flat portion 57 Rotation detection flag 58 Rotation Detection sensor 60 Drive motor 70 CPU
100Y-100Bk image forming unit

Claims (7)

Developing means for developing the electrostatic latent image formed on the photoreceptor using toner;
A mounting portion on which a storage container storing toner is mounted;
A mounting detecting means for detecting that a storage container is mounted on the mounting portion;
Drive means for rotating the storage container mounted on the mounting portion with a driving force corresponding to an electric current in order to replenish toner from the storage container to the developing means;
Rotation detection means for detecting rotation information of the container rotated by the driving means;
Control means for controlling the current supplied to the drive means so that the rotation speed of the container becomes a predetermined speed based on the rotation information detected by the rotation detection means;
When the control unit detects that the storage container is mounted on the mounting unit by the mounting detection unit after the storage container mounted on the mounting unit is removed, the control unit removes the storage container from the mounting unit. If the current supplied to the driving means by the control means before being removed is less than a predetermined value, the current to be supplied to the driving means is changed to a current higher than the predetermined value. apparatus.   The rotation detection means includes a detected portion provided on an outer peripheral surface of the container and a phase detection means for detecting the detected portion, and uses the time for the phase detection means to detect the detected portion. The image forming apparatus according to claim 1, wherein a rotation speed of the container is detected.   The control means sets a current higher than the predetermined value so as to obtain a driving torque capable of rotating the storage container once within a predetermined time even when the drive torque of the storage container is maximum. The image forming apparatus according to claim 1 or 2.   4. The image formation according to claim 1, wherein the control unit determines that the container is replaced when the output of the attachment detection unit changes from non-detection to detection. 5. apparatus. Storage means for storing a current value supplied to the driving means before the container is replaced;
5. The image formation according to claim 1, wherein the control unit confirms the current value stored in the storage unit and sets a current value higher than the predetermined value. 6. apparatus.   The control means supplies the drive means after replacement of the storage container when the current supplied to the drive means by the control means before the storage container is removed from the mounting portion is within a predetermined range. 6. The image according to claim 1, wherein the current supplied to the driving unit by the control unit before the container is removed from the mounting portion is set as a current to be performed. Forming equipment. The container is
An accommodating portion for accommodating the developer;
A discharge portion for discharging the developer toward the developing means;
A transport unit that transports the developer in the storage unit toward the discharge unit;
A driving force input unit for receiving a rotational driving force from the driving means;
A driving force conversion mechanism that converts the rotational driving force input to the driving force input unit into a reciprocating driving force;
A pump unit that repeats expansion and contraction by the reciprocating driving force;
Have
The control means includes
7. The image according to claim 1, wherein the developer is controlled to be replenished to the developing unit via the discharge unit by expansion and contraction of the pump unit. 8. Forming equipment.