JP2018120001A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer supply system that, even when the amount of developer in a developer bottle is reduced, can move a sufficient amount of developer from the developer bottle to a discharge part to stabilize the amount of developer discharged from the discharge part.SOLUTION: A developer supply system detects the amount of developer remaining in a developer bottle 50 with a residual amount sensor 55 in the developer bottle, and when the amount of developer remaining in the developer bottle 50 becomes less than a predetermined amount, controls the number of rotations of a rotation driving part 52 rotating the developer bottle 50 to be increased with respect to the number of discharge performed by a discharge part 51, and thereby can stably supply developer even when the amount of developer in the developer bottle 50 is reduced.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a developer supply system and an image forming apparatus including the developer supply system.

  2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses such as copying machines, printers, and facsimiles are known. In an electrophotographic image forming apparatus, an electrostatic latent image is formed on the surface of a photosensitive member, for example, a photosensitive drum, and toner is replenished to the photosensitive drum by a developing device to convert the electrostatic latent image into a toner. Develop as an image. Thereafter, the toner image formed on the photosensitive drum is transferred to a recording medium such as paper and fixed by a fixing device.

  A fine powder developer is used in an image forming apparatus such as an electrophotographic copying machine. In such an image forming apparatus, the developer consumed in association with image formation is supplied from a developer supply container.

  As such a conventional developer replenishing container, in the apparatus described in Patent Document 1, a bellows-like pump is provided in the developer replenishing container, and this pump is driven through a discharge port by a driving force input from the image forming apparatus side. An intake operation and an exhaust operation are alternately and repeatedly switched. Such a bellows pump is operated so that the developer can be discharged from the developer supply container to the transport path and transported to the developing device.

  In such a configuration, when the remaining amount of developer in the developer supply container decreases due to use by the user, the ratio of the volume of air to the developer in the developer supply container increases. Since the pressure applied to the developer by the pump is inversely proportional to the volume of air in the pump and developer supply container, the pressure generated by the contraction of the pump increases the volume of air without developer generated in the developer supply container. In some cases, the developer discharge performance may be reduced.

  In order to solve this problem, in Patent Document 1, when the developer in the developer supply container decreases, the operation is stopped in a state where the pump portion is extended, and the developer accommodating portion is rotated in the meantime. A configuration is shown in which the toner is continuously conveyed from the developer container to the discharge portion. Thereby, the discharge portion can be sufficiently filled with the developer, and a stable developer discharge amount can be maintained until the developer in the developer supply container becomes empty.

JP 2010-256894 A

  However, in the configuration as in Patent Document 1, when the amount of developer in the developer supply container decreases, the pump operation is stopped, the developer accommodating portion is rotated, and the developer is continuously conveyed. In this state, when the amount of developer in the developer supply container is small and the image forming operation is continued at a low printing rate, the developer is not instructed to supply the developer and the discharge unit is not driven to discharge. However, since the number of rotations of the developer container during that period is not controlled, the developer is continuously conveyed from the developer supply container toward the discharge unit. In such a case, there is a problem that the developer is excessively conveyed to the discharge unit, and the developer clogging occurs in the discharge unit called packing.

  The present invention has been made in view of the above-described problems in the prior art, and an object thereof is to stably discharge a developer.

  For this purpose, the developer replenishment system according to the present invention feeds the developer accommodated in the developer accommodating portion to the developer discharging portion by the developer feeding portion, and replenishes the developer from the developer discharging portion to the developing device. A developer replenishment system that determines the remaining amount of developer in the developer container, and the remaining amount determining unit determines that the remaining amount of developer has decreased to a predetermined amount. And changing means for changing the ratio of the feeding operation of the feeding means to the discharging operation of the developer discharging section to a predetermined ratio determined according to the predetermined amount. Is.

  According to the present invention, the developer can be discharged stably.

Schematic configuration diagram of an image forming apparatus Expanded configuration diagram of the image forming unit Configuration diagram of developer supply mechanism Conveyance path configuration diagram Configuration diagram of developer sensor The figure showing the relationship between the developer remaining amount and the output voltage of the developer sensor An example of a method for determining whether a developer is present or not Control block diagram Control flowchart in the first embodiment The figure which shows the relationship between the developer residual amount in a developer bottle when a developer bottle is rotated 1 time, and the developer movement amount to a discharge part. The figure which shows the relationship between the developer residual amount in a developer bottle, and the developer storage amount of a discharge part. The figure which shows the relationship between the developer discharge amount per drive of a discharge part, and the developer residual amount in a developer bottle. Flowchart in the second embodiment

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in the following embodiments are appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, there are particularly specific descriptions. It is not intended to limit the scope of the invention only to those unless otherwise specified. In the following embodiments, at least a portion to be used in a series of flows for replenishing the developer to the developing device is referred to as a developer replenishing system.

(First embodiment)
The image forming apparatus of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 of the present embodiment.

In the image forming apparatus 100 shown in FIG. 1, the recording medium P accommodated in a feeding cassette 101 is fed out by a feeding roller 102 and fed one by one in cooperation with a separation device (not shown).
Thereafter, the leading end portion of the recording medium P comes into contact with the nip region of the registration roller 103 that has stopped once, and the skew is corrected by the waist force of the recording medium P. Further, the skewed recording medium P is conveyed to the image forming unit 104, and an image is formed on the recording medium P.

  The image forming unit of this embodiment will be described with reference to FIG. FIG. 2 is an enlarged view of the image forming unit 104 shown in FIG.

  In this embodiment, the image forming apparatus 100 includes a rotatable drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum 1) 1 as an image carrier. Around the photosensitive drum 1, image forming process means according to this embodiment is arranged. That is, a charging roller 2 as a contact charging member, an exposure device 3, a developing device 4, a transfer roller 5 as a contact transfer member, and a cleaning device 7 are provided.

  A fixing device 6 is provided on the downstream side of the nip area formed between the photosensitive drum 1 and the transfer roller 5 in the recording medium P conveyance direction.

In the present embodiment, the photosensitive drum 1 is a negatively chargeable organic photoconductor (OPC) having an outer diameter of 30 mm, and is driven to rotate in the direction of an arrow (counterclockwise in FIG. 2) by driving of a driving unit (not shown).
A charging bias voltage of a predetermined condition is applied to the charging roller 2 from a power source (not shown), so that the peripheral surface of the photosensitive drum 1 is charged to a predetermined polarity and potential at the charging position a, and a uniform charging process is performed. .

The exposure apparatus 3 uses a semiconductor laser in the present embodiment, and outputs a laser beam L modulated in accordance with an image signal input from a host process such as an image reading apparatus (not shown) to perform photosensitivity. The uniformly charged surface of the drum 1 is subjected to scanning exposure (image exposure) at the exposure position b.
By scanning and exposing the uniformly charged surface, the potential of the portion irradiated with the laser beam on the surface of the photosensitive drum 1 is lowered. That is, electrostatic latent images corresponding to image information subjected to scanning exposure are sequentially formed on the surface of the photosensitive drum 1.

  The developing device 4 replenishes toner (developer) to an exposed portion (electrostatic latent image) on the surface of the photosensitive drum 1, and the replenished developer adheres to visualize the electrostatic latent image.

  The developing device 4 is provided with a developing sleeve 8 that can rotate in the direction of the arrow (counterclockwise in FIG. 2) as indicated by an arrow at the opening of the developing container 7, and the developer in the developing container 7 is supplied with the developing sleeve 8. A layer is formed thereon, and the developer is transported to the developing unit c facing the photosensitive drum 1 to replenish the developer to the electrostatic latent image on the surface of the photosensitive drum 1.

  The developer in the developing container 7 is a mixture of toner and magnetic carrier, and is conveyed to the developing sleeve 8 side while being uniformly stirred by the rotation of the stirring member 10 that can rotate in the direction of the arrow (clockwise in FIG. 2). .

  Further, the developer in the developer container 7 is detected by the developer sensor 11 in the developer container, and a replenishment command signal and a replenishment stop signal to the developer container 7 are issued based on this detection information.

  The developer bottle 50 that has received the replenishment command signal to the developer container 7 receives the drive from the rotation drive unit 52 by the drive transmission unit 53 and performs the discharge drive of the discharge unit 51 to remove the developer from the developer bottle 50. Discharge. Detailed discharge driving of the developer will be described later.

  The developer discharged from the developer bottle 50 by driving the discharge unit 51 is supplied to the transport path 59 through the supply port 58 connected to the discharge unit 51.

  A conveying screw 12 as a developer conveying means for conveying the developer to the developing container 7 is provided in the conveying path 59. Similarly, an in-conveyance path developer sensor 13 for detecting the developer in the conveyance path 59 at a position substantially immediately below the supply port 58 is disposed outside the conveyance path 59.

  The developer conveyed on the conveyance path 59 by the conveyance screw 12 is supplied to the developing container 7 through the supply port 14 shown in FIG.

  A conveyance screw 15 is provided at a position where the developer is supplied from the supply port 14 and dropped. The developer is supplied to the developing container 7 by the conveying screw 15.

  The transfer roller 5 is brought into contact with the photosensitive drum 1 with a predetermined pressing force to form a transfer portion d, and is driven to rotate in the arrow direction. Further, a transfer bias (positive transfer bias having a polarity opposite to the negative polarity that is the normal charging polarity of the toner) is applied from a power source (not shown). As a result, the toner image on the surface of the photosensitive drum 1 is transferred to the recording medium P such as paper at the transfer portion d.

  Further, in the cleaning device 16, the surface of the photosensitive drum 1 after the transfer of the toner image to the recording medium P is rubbed by the cleaning blade 16a to be cleaned to remove the transfer residual toner, and repeatedly used for image formation. . In FIG. 2, e is the photosensitive drum 1 surface contact portion of the cleaning blade 16a.

  The fixing device 6 has a fixing roller 6a and a pressure roller 6b that are rotatable in the direction of the arrow, and performs recording while holding the recording medium P in the fixing nip region between the fixing roller 6a and the pressure roller 6b. The toner image transferred to the surface of the medium P is heat-fixed by heating and pressing. Here, the fixing device 6 is provided downstream in the conveyance direction of the photosensitive drum 1, and the arrow of the recording medium P indicates the conveyance direction.

  Next, the developer supply mechanism in the present embodiment will be described.

  FIG. 3 is a schematic view of a developer replenishing mechanism using the developer bottle 50 shown in FIG. 3A is a side view of the developer replenishing mechanism when the developer is not discharged according to the present embodiment, and FIG. 3B is a bottom view of the developer replenishing mechanism when the developer is not discharged according to the present embodiment. FIG. 3C is a side view of the developer supply mechanism when the developer is discharged according to this embodiment, and FIG. 3D is a view when the developer supply mechanism when the developer is discharged according to this embodiment. It is the figure seen from the bottom.

  As shown in FIGS. 3A, 3 </ b> B, 3 </ b> C, and 3 </ b> D, the mechanism for supplying the developer includes a rotation driving unit 52 that rotates the developer bottle 50 and a rotation of the rotation driving unit 52. Is transmitted to the developer bottle 50, and a mounting portion 54 that mounts the developer bottle 50 on the discharge portion 51. The developer bottle 50 is detachably attached to the attachment portion 54.

  A spiral protrusion 50A is formed on the inner peripheral surface of the developer bottle 50 so as to protrude inward of the developer bottle 50, and the developer is discharged from the developer bottle 50 along the protrusion 50A by rotation. Will be guided to. The developer bottle 50 is provided with a developer bottle remaining amount sensor 55 described later, and detects the remaining amount of developer in the developer bottle 50.

  Here, as means for detecting the developer remaining amount in the developer bottle 50, means for detecting the developer remaining amount in the developer bottle 50, such as a configuration estimated from the dot count value and the rotation speed N of the developer bottle 50. If it is good.

  In the present embodiment, a resin variable volume pump whose volume is variable with reciprocating motion is adopted as the discharge unit 51. Specifically, a bellows-like pump is employed, and a plurality of “mountain folds” and “valley folds” are periodically and alternately formed. The discharging unit 51 is driven as described below by a discharging unit driving unit 56 described later.

  3A and 3B show a state in which the discharge unit 51 is extended to the maximum extent in use, and the developer is not discharged in this state.

3 (c) and 3 (d) show a state in which the discharge unit 51 is maximally contracted in use, and the developer is discharged when the expanded state is shifted to the contracted state.
That is, the discharge unit 51 of the present embodiment functions as an intake / exhaust mechanism that alternately performs an intake operation and an exhaust operation via the discharge port 58.

  In other words, the discharge unit 51 functions as an air flow generation mechanism that alternately and repeatedly generates an air flow directed toward the inside of the developer bottle 50 and an air flow directed toward the outside from the developer bottle 50.

  Therefore, the discharge unit 51 can repeatedly perform contraction and expansion alternately (expand and contract) by the driving force received from the rotational drive mechanism 52. In the present embodiment, the volume change amount when the discharge portion 51 is expanded and contracted is set to 17 cm ^ 3 [cc], and the contraction cycle is set to 0.3 [sec].

  By adopting such a discharge part 51, it becomes possible to change the volume of the discharge part 51 and to change it alternately and repeatedly at a predetermined cycle.

  That is, when the discharge part 51 is extended as shown in FIGS. 3A and 3B, the volume increases, and when the discharge part 51 is contracted as shown in FIGS. 3C and 3D. Has a smaller volume. In this way, the volume changes with the expansion and contraction of the discharge unit 51.

  Next, the toner conveyance path configuration, toner replenishing means, and remaining amount detecting means will be described with reference to FIG. 4 is a schematic view of the conveyance path 59 shown in FIG. 2, FIG. 4 (a) is a cross-sectional view seen from a direction perpendicular to the direction in which the developer is conveyed, and FIG. 4 (b) is a developer conveyance. FIG. 6 is a cross-sectional view viewed in the horizontal direction with respect to the developer conveyance direction from the downstream side of the direction.

  A conveying screw 12 as a developer conveying means for conveying the developer to the developing container 7 is provided in the conveying path 59. Similarly, an in-conveyance path developer sensor 13 for detecting the developer in the conveyance path 59 at a position substantially immediately below the discharge port 58 is disposed outside the conveyance path 59.

  Next, the developer sensor 11 in the developing container and the developer sensor 13 in the transport path will be described in detail with reference to FIG. FIG. 5 is a schematic configuration diagram of the magnetic bridge sensor 20 as the developer sensor 11 in the developing container and the developer sensor 13 in the conveyance path shown in FIG.

  In this embodiment, a magnetic bridge sensor 20 is used as the developer sensor 11 in the developing container and the developer sensor 13 in the transport path. As shown in FIG. 5, the magnetic bridge sensor 20 is integrally formed in a shape in which a detection head 20b is placed on a main body portion 20a, and is connected to an image forming apparatus main body via an input / output signal line 20c. Send and receive detection signals between.

  A detection transformer (not shown) is embedded in the detection head 20b, and this detection transformer includes a total of three primary windings and two secondary windings including a reference winding and a detection winding. Consists of windings. The detection winding is positioned on the top side of the detection head 20b, and the reference winding is positioned on the back side of the detection head 20b with the primary winding interposed therebetween.

  When a current having a signal having a constant waveform is input to the primary winding from the transmitter provided in the main body 20a, the two secondary windings including the reference winding and the detection winding are also electromagnetically induced or A current with a waveform signal flows. The detection head 20b is determined by determining a signal having a constant waveform from the transmitter at this time and a signal having a certain waveform of the current flowing from the detection winding by electromagnetic induction by a comparison circuit provided in the main body 20a. The density of the magnetic material is detected on the top surface side of the.

  That is, different outputs can be obtained depending on whether or not a magnetic body is present in front of the detection head 20b. The magnetic bridge sensor 20 is provided with a ferrite screw core (not shown) movably provided at the center of the detection transformer in order to cope with the difference in magnetic density and the like of the magnetic material to be detected. Appropriate detection is possible by adjusting. In addition, the detection range of the detection head 20b of the magnetic bridge sensor 20 is set to be larger than the range from when the developer is fully charged until it becomes empty.

  Here, the developer amount detection method of the magnetic bridge sensor 20 will be described with reference to FIG. FIG. 6 is a graph showing the relationship between the developer remaining amount and the output voltage of the magnetic bridge sensor.

  As shown in FIG. 6, the magnetic bridge sensor 20 shows the highest output voltage when the remaining amount of developer in the developer container 7 or the developer transport path 59 is in the maximum filling state (Full state), and the remaining developer amount. When the quantity is empty (Empty state), it shows the lowest output voltage. Since an output voltage corresponding to the remaining amount of developer is output between the Full state and the Empty state, the output voltage corresponding to the remaining amount of developer is detected to detect the output voltage in the developer transport path 59 or the developer container. The developer remaining amount in 7 can be detected.

  Next, a specific determination method for the presence / absence of developer in the developer sensor 11 in the developing container and the developer sensor 13 in the transport path will be described with reference to FIG. FIG. 7 shows an example of a method for determining whether or not there is a developer in the present embodiment.

  The developer sensor 11 in the developing container and the developer 13 in the transport path output a developer presence signal when an output voltage equal to or higher than a predetermined output voltage corresponding to a predetermined developer remaining amount is detected.

  In this embodiment, the developer remaining signal in the developer container 7 or the developer transport path 59 is detected 15 times every 100 ms, and the developer presence signal is detected among the 15 detections. When the number of times is 3 or more out of 15 (in the case of the result N shown in FIG. 7), it is determined that the developer is present in the developer container 7 or the developer transport path 59.

  When the developer sensor 11 in the developer container determines that the developer is present, the supply of the developer from the developer transport path 59 to the developer container 3 is stopped. If the developer sensor 11 in the developing container 11 or the developer sensor 13 in the transport path determines that the developer is present, the supply of the developer from the developer bottle 50 to the developer transport path 59 is stopped.

  Further, out of the 15 detections, when the detection of the developer presence signal is less than 3 times (in the case of the results K, L, and M shown in FIG. 7), in the developer container 7 or the developer conveyance path 59. It is determined that there is no developer. When the developer sensor 11 in the developing container determines that there is no developer, the developer is replenished from the developer conveying path 59 to the developing container 3. When both the developer sensor 11 in the developer container and the developer sensor 13 in the transport path determine that there is no developer, the developer is replenished from the developer bottle 50 to the developer transport path 59.

  If the developer sensor 13 in the transport path determines that there is a developer, and the detection result of the developer bottle remaining amount sensor 55 indicates that there is no remaining amount, the near-end state indicates that there is no developer supplied to the developer container 3. Although the image forming operation is continued, the user is warned that the remaining amount in the developer bottle 50 is zero.

If the developer sensor 11 in the developing container and the developer sensor 13 in the transport path determine that there is no developer, and the detection result of the developer bottle remaining amount sensor 55 indicates that there is no remaining amount, go to the developing container 3. Since there is no developer to be supplied and there is no developer in the developer container 3, it is determined that the developer is in an end state indicating that no developer that can be used for image formation remains. In that case, the image forming operation is prohibited, and the user is prompted to replace the developer bottle 50.
Next, the control configuration of the CPU 30 will be described with reference to FIG. FIG. 8 is a block diagram showing a control configuration of the CPU 30 of the present embodiment.

  The CPU 30 drives the rotation driving unit 52, the discharge unit driving unit 54, the developing container driving unit 31, and the transport path driving unit 32 shown in FIG. 2 based on the detection results of the developer sensors 11 and 13 in the developing container, and develops them. The supply of the developer to the container 7 and the conveyance path 59 is controlled.

  Various control programs for image formation are stored in a ROM (Read Only Memory). A RAM (Random Access Memory) temporarily stores various data during execution of the control program.

  Further, the display unit 57 includes a developer that is determined based on the detection results of the operation state and operation message of the image forming apparatus, or the remaining amount sensor 55 in the developer bottle, the developer sensor 11 in the developer container, and the developer sensor 13 in the conveyance path. The end state or near end state is displayed.

  Next, a developer replenishment flow of the developer bottle 50 in this embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing the operation of the CPU 30 in this embodiment.

  First, in S101, the CPU 30 determines whether or not an image forming operation has been started, and determines that the image forming operation has started. In S102, the CPU 30 enters the developing container 7 from the detection result of the developer sensor 11 in the developing container. Determine if there is developer.

  If the CPU 30 determines in S102 that the developer is present in the developing container 7 from the detection result of the developer sensor 11 in the developing container, in S103, the CPU 30 determines whether or not the conveyance path screw 15 is driven.

  If the CPU 30 determines that the conveyance path screw 15 is driven in S103, the CPU 30 stops the conveyance path screw 15 in S104, and in S105, the CPU 30 determines from the detection result of the developer bottle residual amount sensor 55. Then, it is determined whether or not there is a developer in the developer bottle 50. On the other hand, when the CPU 30 determines in S103 that the transport path screw 15 is not driven, the CPU 30 executes the step of S105 as it is.

  If the CPU 30 determines in S105 that there is no developer in the developer bottle 50, in S106, the CPU 30 displays a near-end notification on the display unit 57, and in S107, the CPU 30 determines whether the image forming operation is completed. To do. If the CPU 30 determines in S105 that the developer is present from the detection result of the developer bottle residual amount sensor 55, the CPU 30 executes the step of S107 as it is.

  When the CPU 30 determines in S107 that the image forming operation has been completed, the CPU 30 ends the developer supply flow. If the CPU 30 determines in S107 that the image forming operation has not been completed, the CPU 30 executes the flow subsequent to S102 again.

  If the CPU 30 determines in S102 that there is no developer in the developer container 7 from the detection result of the developer sensor 11 in the developer container, in S108, the CPU 30 determines the transport path from the detection result of the developer sensor 13 in the transport path. It is determined whether the developer is present in 59.

  If the CPU 30 determines that the developer is present in the conveyance path 59 in S108, in S109, the CPU 30 drives the conveyance path driving unit 32 to drive the conveyance path screw 15, and executes the flow subsequent to S102 again.

  If the CPU 30 determines in S108 that there is no developer in the transport path 59 from the detection result of the developer sensor 13 in the transport path, the CPU 30 determines that the development is based on the detection result of the developer bottle remaining amount sensor 55 in S110. It is determined whether or not there is a developer remaining amount in the developer bottle 50.

  When the CPU 30 determines in S110 that there is no developer remaining amount in the developer bottle 50 from the detection result of the developer bottle remaining amount sensor 55, in S111, the CPU 30 causes the display unit 57 to display a bottle replacement notification. In S112, the CPU 30 stops the image forming operation and ends the developer supply flow.

  If the CPU 30 determines in S110 that there is a developer remaining amount in the developer bottle 50 from the detection result of the developer bottle remaining amount sensor 55, in S113, the CPU 30 detects the detection result of the developer bottle remaining amount sensor 55. To determine whether or not the remaining amount of developer in the developer bottle 50 is 300 g or more.

  When the CPU 30 determines in S113 that the developer remaining amount in the developer bottle 50 is 300 g or more from the detection result of the developer bottle remaining amount sensor 55, in S114, the CPU 30 determines the rotation speed N of the rotation drive unit 52. Is set to once.

  In step S115, the CPU 30 rotates the developer bottle 50 by driving the rotation driving unit 52 by the number of rotations N set in step S114. Thereafter, in S116, the CPU 30 drives the discharge unit drive unit 54 to drive the discharge unit 51 once, and executes S108 and subsequent steps again.

  When the CPU 30 determines in S113 that the developer remaining amount in the developer bottle 50 is less than 300 g from the detection result of the developer bottle remaining amount sensor 55, in S117, the CPU 30 determines the rotational speed N of the rotation drive unit 52. Is set to 3 times, and the flow after S115 is executed.

  Here, the relationship between the developer remaining amount in the developer bottle 50 and the amount of developer that moves from the developer container to the discharge unit 51 when the developer bottle 50 is rotated once will be described with reference to FIG. FIG. 10 is a graph showing the relationship between the developer remaining amount in the developer bottle 50 and the amount of developer movement to the discharge unit 51 when the developer bottle 50 is rotated once.

  It can be seen that as the developer remaining amount in the developer bottle 50 decreases, the amount of developer movement to the discharge unit 51 gradually decreases. In this embodiment, the amount of developer discharged per pump is set to about 2 g. Therefore, it is desired to stably move 2 g or more of the developer to the discharge unit 51. However, when the developer in the developer bottle 50 is less than 300 g as shown in FIG. 10, the developer transfer amount to the discharge unit 51 is 2 g. Less than

  That is, when the developer remaining amount in the developer bottle 50 falls below 300 g, the rotation speed N of the developer bottle 50 is increased to stabilize the discharge amount per pump, and 2 g is supplied to the discharge unit 51. It is necessary to be able to move above. Since the developer can be moved by 0.9 g or more when the developer remaining amount in the developer bottle 50 is up to 50 g, even when the developer remaining amount in the developer bottle 50 is reduced to 50 g, the developer bottle 50 Can be moved by 0.9 × 3 times = 2.7 g.

  FIG. 11 is a graph showing the relationship between the remaining amount of developer in the developer bottle 50 and the amount of developer stored in the discharge unit 51.

  In the case where the present embodiment is not carried out (the solid line portion), when the developer remaining amount decreases to less than 300 g, as shown in FIG. 10, the developer movement amount from the developer bottle 50 to the discharge unit 51 is 1 pump. The amount of developer stored in the discharge portion 51 is reduced below 2 g of the discharge amount that can be discharged. Furthermore, if it reduces to about 100g, the developer storage amount of the discharge part 51 will also be less than 2g.

  In the case where the present embodiment is implemented (broken line portion), the rotation speed N of the developer bottle 50 is increased, so that even when the remaining amount of developer is reduced, the discharge unit 51 can be stably moved by 2 g or more. Therefore, the developer storage amount of the discharge unit 51 can be stably maintained.

  Next, the relationship between the developer discharge amount per driving of the discharge unit 51 and the remaining amount of developer in the developer bottle 50 will be described with reference to FIG. FIG. 12 is a graph showing the relationship between the developer discharge amount per driving of the discharge unit 51 and the developer remaining amount in the developer bottle 50.

  When this embodiment is not carried out (solid line portion), when the remaining amount of developer in the developer bottle 50 decreases and falls below 150 g, the developer discharge amount that has been stably 2 g or more decreases. As shown in FIGS. 10 and 11, as the developer remaining amount decreases, the amount of developer movement from the developer bottle 50 to the discharge unit 51 decreases, and as a result, the developer storage in the discharge unit 51 occurs. This is because the amount is reduced.

  When this embodiment is implemented (broken line portion), as shown by the broken line portion in FIGS. 10 and 11, even when the amount of developer in the developer bottle 50 decreases, the discharge portion 51 is stably 2 g or more. Since the developer storage amount of the discharge unit 51 can be stably maintained, 2 g can be stably supplied from the discharge unit 51 to the conveyance path 59.

  According to the above-described embodiment, the developer can be replenished stably even when the amount of developer in the developer bottle 50 becomes empty.

(Second Embodiment)
In the above-described first embodiment, when the remaining amount of developer in the developer bottle 50 reaches a predetermined amount, the ratio of the rotation speed N of the developer bottle 50 to one pump is changed to change the developer bottle. The configuration in which the developer can be used up until the developer bottle 50 is empty while the developer is stably replenished from 50 to the conveyance path 59 is shown. It has been described that the rotation speed N of the developer bottle 50 at this time requires at least three rotations.

  However, since the developer movement amount from the developer bottle 50 to the discharge portion 51 due to the rotation of the developer bottle 50 changes stepwise depending on the remaining amount of developer in the developer bottle 50, the developer remaining in the developer bottle 50 is Even when the amount reaches a predetermined amount, the rotation speed N of the developer bottle 50 may not necessarily be three, and the rotation driving unit 52 may be driven unnecessarily. Therefore, in the present embodiment, the ratio of the number of rotations of the developer bottle 50 to one pump is changed stepwise according to the remaining amount of developer.

  A developer supply flow of the developer bottle 50 in the present embodiment will be described with reference to FIG. FIG. 13 is a flowchart showing the operation of the CPU 30 in this embodiment.

  The developer replenishment flow in the present embodiment performs the same operation up to the flow of S113 in the developer replenishment flow shown in FIG. 9 of the first embodiment described above, and therefore a flow of a portion different from the first embodiment after S113. Only will be described. Also, the same parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  When the CPU 30 determines in S113 that the developer remaining amount in the developer bottle 50 is 300 g or more from the detection result of the developer bottle remaining amount sensor 55, in S201, the CPU 30 determines the rotational speed N of the rotation drive unit 52. Is set to once.

  In step S <b> 202, the CPU 30 rotates the developer bottle 50 by driving the rotation driving unit 52 by the set number of rotations N. Thereafter, in S203, the CPU 30 drives the discharge unit driving unit 54 once to drive the discharge unit 51, and executes S108 and subsequent steps again.

  When the CPU 30 determines in S113 that the developer remaining amount in the developer bottle 50 is less than 300 g from the detection result of the developer bottle remaining amount sensor 55, in S204, the CPU 30 determines in the developer bottle remaining amount sensor 55. From the detection result, it is determined whether the developer remaining amount in the developer bottle 50 is 150 g or more.

  If the CPU 30 determines in S204 that the remaining amount of developer in the developer bottle 50 is 150 g or more, in S205, the CPU 30 sets the rotation speed N of the rotation drive unit 52 to 2 times, and the flow from S202 onward. Run.

  When the CPU 30 determines in S204 that the developer remaining amount in the developer bottle 50 is less than 150 g, in S206, the CPU 30 sets the rotation speed N of the rotation drive unit 52 to 3 times, and the flow from S202 onward. Run.

  As described above, by controlling the rotation speed N of the rotation driving unit 52 in accordance with the remaining amount of developer in the developer bottle 50, the rotation driving unit 52 is not driven unnecessarily, and the developer bottle 50 has an inside. Even if the amount of the developer becomes empty, the developer can be replenished stably.

(Other embodiments)
In each of the above-described embodiments, when the remaining amount of developer in the developer bottle is less than a predetermined amount, the rotation number of the rotation drive unit is increased. However, the present invention is not limited to this. Even if the rotational speed of the rotational drive unit is reduced when the initial rotational speed is set to a high rotational speed and the remaining amount of developer in the developer bottle is equal to or greater than the predetermined amount, The invention can be applied.

  Further, in each of the above-described embodiments, when the developer remaining amount in the developer bottle becomes less than a predetermined amount, the rotation number of the rotation drive unit is increased. However, the present invention is applied to this. The present invention can also be applied to a configuration in which the number of discharges of the discharge unit is reduced with respect to the number of rotations of the drive rotation unit without changing the rotation number of the rotation drive unit.

  Further, in each of the above-described embodiments, the number of rotations of the rotation drive unit is increased by a predetermined number of times according to the amount of developer remaining in the developer bottle. The present invention can also be applied to a configuration in which the ratio of the number of discharges of the discharge unit and the number of rotations of the rotation drive unit is controlled at any time according to the developer remaining amount in the agent bottle.

  In each of the above-described embodiments, the bellows-type variable volume pump is used as the discharge unit. However, the present invention is not limited to this, and the discharge unit has an opening, and the rotation drive unit rotates a predetermined number of times. The present invention can be applied even when the developer is discharged by opening the discharge portion each time the developer is opened.

11 Developer sensor in developer container 13 Developer sensor in transport path 15 Transport path screw 30 CPU
DESCRIPTION OF SYMBOLS 50 Developer bottle 51 Discharge part 52 Rotation drive part 55 Developer bottle remaining amount sensor 59 Conveyance path 100 Image forming apparatus 104 Image forming part

Claims (7)

A developer replenishment system for supplying a developer contained in a developer accommodating portion to a developer discharging portion by a developer feeding portion and replenishing the developer from the developer discharging portion to a developing device, wherein the developer accommodating portion A remaining amount determining means for determining the remaining amount of developer in the section, and a discharging operation of the developer discharging section in response to the remaining amount determining means determining that the remaining developer amount has decreased to a predetermined amount And a changing means for changing the ratio of the feeding operation of the feeding means to a predetermined ratio determined according to the predetermined amount. The changing unit is configured such that when the remaining amount determining unit determines that the amount has decreased to the predetermined amount, the number of discharging operations of the discharging unit is smaller than the number of feeding operations of the developer feeding unit. The developer replenishing system according to claim 1, wherein the developer replenishing system is controlled. When the changing means determines that the remaining amount determining means has decreased to a second predetermined amount that is less than the predetermined amount, the changing means indicates that the remaining amount determining means has decreased to the predetermined amount. 3. The developer supply system according to claim 2, wherein control is performed such that the number of discharge operations of the discharge unit is further reduced with respect to the number of feed operations of the developer supply unit, as compared with the case of determination. . When the change means determines that the remaining amount determination means has decreased to the predetermined amount, the change means counts the number of feeding operations of the developer feeding section with respect to the number of discharge operations of the discharge section. The developer replenishing system according to claim 1, wherein the developer replenishing system is controlled so as to increase. When the changing means determines that the remaining amount determining means has decreased to a second predetermined amount that is less than the predetermined amount, the changing means indicates that the remaining amount determining means has decreased to the predetermined amount. 5. The developer supply system according to claim 4, wherein the developer replenishing system is controlled so that the number of times of the feeding operation of the developer feeding unit is larger than the number of times of the discharging operation of the discharging unit. The developer supply system according to claim 1, wherein the discharge unit is a discharge unit that discharges the developer with a predetermined pressure. 7. A developer replenishing system according to claim 1, and image forming means for forming an image on a recording medium with the developer replenished by the developer system. An image forming apparatus.

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