JP2018072553A - Developer supply device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer supply device that can reduce developer supply time with a simple configuration.SOLUTION: A developer supply device comprises: a pump 51 for supplying, to a developing unit 3, toner inside a removable toner bottle 50 that stores the toner; and a CPU 70 that causes the pump 51 to carry out developer supply operation, and, when determining that the toner bottle 50 is newly attached, can set time when the pump 51 continuously supplies the toner to be longer than time when, subsequent thereto, the pump 51 supplies the toner.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a developer supply device suitable for an electrophotographic image forming apparatus such as a laser beam printer or an LED printer.

  In an electrophotographic image forming apparatus, toner (developer) stored in a developing device is supplied by a developing sleeve to an electrostatic latent image formed on the surface of a photosensitive drum (image carrier). Thus, a toner image is formed on the photosensitive drum.

  Further, the toner supply to the developing device is performed from the toner filled in the toner bottle (developer container), and when the toner in the toner bottle runs out, an empty toner bottle and a new toner bottle can be exchanged. Is widely known.

  Here, after replacement of a new toner bottle, the toner may become clogged and it may be difficult to discharge the toner from the toner bottle. This occurs, for example, when the toner bottle is stored vertically for a long time with the discharge port of the toner bottle down, or when transportation or storage is performed in a state other than the preferred state.

  Thus, a configuration for eliminating the phenomenon of toner clogging has been proposed. For example, Patent Document 1 describes a configuration in which a toner transport expected value and an actually received toner amount are detected by a weight sensor, and when the difference is equal to or greater than a predetermined value, it is determined that the toner is clogged and the screw in the toner transport path is rotated backward. Has been.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a configuration in which after a toner clogging is detected by a sensor, vibration is applied to eliminate the clogged state.

JP-A-10-268725 Japanese Patent Laid-Open No. 11-52811

  However, in the case of eliminating the toner clogging with the configuration described in Patent Document 1, the toner replenishment time is extended by the time for rotating the screw in the reverse direction. Further, when a toner clog occurs in a portion outside the screw conveyance, the toner clog cannot be eliminated.

  Further, when toner clogging is eliminated with the configuration described in Patent Document 2, the configuration is complicated because a sensor that detects toner clogging, a member that receives a signal from the sensor and applies vibration to the sensor, and a control system are necessary.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developer replenishing device capable of shortening the developer replenishment time with a simple configuration.

  In order to achieve this object, a developer replenishing device according to the present invention includes a supply means for supplying a developer in a detachable developer storage container for storing a developer to a developing device, and developing the supply means. A supply operation of the developer, and when it is determined that the developer storage container is newly installed, the supply unit continuously supplies the developer after the time for supplying the developer is determined. And control means that can be set to a longer time than the supply time.

  According to the present invention, the developer replenishment time can be shortened with a simple configuration.

1 is a schematic cross-sectional view of an image forming apparatus. It is an enlarged view of an image forming unit. It is the graph which shows the perspective view and output characteristic of a sensor in a conveyance path. 2 is a block diagram of a control unit of the image forming apparatus. FIG. FIG. 2 is a side view and a plan view of a toner supply device and a developing device. FIG. 4 is a schematic cross-sectional view and a schematic plan view of a toner replenishing device when a pump expands and contracts. It is sectional drawing and a side view of a conveyance path. 3 is a flowchart of a toner supply sequence according to the first embodiment. It is a table | surface which shows the drive condition of the pump of 1st Embodiment. 6 is a flowchart of a toner supply sequence of a comparative example. 6 is a table for comparing toner replenishment times between the first embodiment and a comparative example. 10 is a flowchart of a toner supply sequence according to a second embodiment. It is a table | surface which shows the drive conditions of the pump of 2nd Embodiment. 10 is a table for comparing toner replenishment times between the second embodiment and a comparative example.

(First embodiment)
<Image forming apparatus>
First, the overall configuration of the image forming apparatus A including the developer supply device according to the first embodiment of the present invention will be described with reference to the drawings together with the operation during image formation. The type, shape, arrangement, number, etc. of the members are not limited to those in the following embodiments, and are appropriately replaced within the scope not departing from the gist of the invention, such as appropriately replacing the constituent elements with those having the same effects. It can be changed.

  As shown in FIG. 1, the image forming apparatus A includes an image forming unit 45 that transfers a toner image onto a sheet, an image reading unit 40 that reads an image of a document, a sheet feeding unit that supplies a sheet to the image forming unit, And a fixing unit 5 for fixing the toner image on the sheet.

  FIG. 2 is an enlarged view of the image forming unit 45. As shown in FIG. 2, the image forming unit 45 includes a photosensitive drum 1 (image carrier) made of an organic photosensitive member, a charging roller 2, a developing device 3, a transfer roller 4, a laser scanner unit 41, a cleaning blade 47, and the like. Prepare. Further, a toner replenishing device 100 (developer replenishing device) that replenishes toner accommodated in the toner bottle 50 to the developing device 3 via the conveyance path 60 is provided.

  In the image formation, as shown in FIG. 1, when the CPU 70 (see FIG. 4) issues a print signal, the sheet S stacked and stored in the sheet stacking unit 43 by a feed roller and a conveyance roller (not shown) is transferred to the image forming unit. 45.

  On the other hand, in the image forming unit 45, as shown in FIG. 2, first, a charging bias is applied to the charging roller 2, whereby the surface of the photosensitive drum 1 in contact with the charging roller 2 is charged.

  Thereafter, the laser scanner unit 41 emits laser light from a light source (not shown) provided therein, and irradiates the photosensitive drum 1 with laser light according to image information read by the image reading unit 40. As a result, the potential of the photosensitive drum 1 is partially reduced, and an electrostatic latent image corresponding to image information is formed on the surface of the photosensitive drum 1.

  Thereafter, a developing bias is applied to the developing sleeve 8 provided in the developing device 3, whereby toner is attached to the electrostatic latent image formed on the surface of the photosensitive drum 1 from the developing sleeve 8 to form a toner image. In this embodiment, a developing bias in which an AC voltage and a DC voltage are superimposed is applied from a high voltage application substrate (not shown). The toner of the present embodiment is a magnetic one-component toner by a pulverization method, the toner particle size is about 5 to 10 μm, and the charge amount is about −5 to −20 uC / g. The configuration of the present invention is not limited to this, and nonmagnetic one-component toner or nonmagnetic two-component toner may be used.

  The toner image formed on the surface of the photosensitive drum 1 is sent to a transfer nip portion formed between the photosensitive drum 1 and the transfer roller 4. When the toner image arrives at the transfer nip portion, a transfer bias having a polarity opposite to that of the toner is applied to the transfer roller 4, and the toner image is transferred to the sheet S.

  Thereafter, the sheet S to which the toner image has been transferred is sent to the fixing unit 5 where it is heated and pressurized at the fixing nip formed between the heating unit and the pressing unit of the fixing unit 5, and the toner image is applied to the sheet. It is fixed. Thereafter, the sheet is conveyed to a discharge roller (not shown) and discharged to the discharge unit 42.

  When the toner in the developing device 3 is reduced, the toner stored in the toner bottle 50 (developer storage container) is supplied to the developing device 3 via the transport path 60. That is, the transport path 60 and the developing device 3 are provided with a transport path sensor 14 and a developer sensor 16 as detection means for detecting the toner amount. Then, the presence or absence of toner is detected by these sensors, and the toner is supplied to the developing device 3 based on the detection result.

  Specifically, in this embodiment, a magnetic bridge sensor, which is a magnetic permeability sensor, is used as the transport path sensor 14 and the developer sensor 16. Since these sensors have the same configuration, the sensor 14 in the transport path will be described with reference to the sensor 14 in the transport path. As shown in FIG. 3A, the sensor 14 in the transport path has a columnar detection head 14b on the main body 14a. It is configured integrally with the shape that is on the board. As shown in FIG. 3B, a high output voltage is shown when the magnetic toner on the top surface side of the detection head 14b is large, and a low output voltage is shown when the toner is small. These detection signals are exchanged with the CPU 70 via the input / output signal line 14c.

  In this embodiment, for the sensor 16 in the developing unit, for example, when the toner weight in the developing unit 3 is about 200 g, the output Duty of the sensor 16 in the developing unit is about 20% and 250 g. A relationship with a duty of 30% is obtained.

  The CPU 70 detects that the toner is present (developer is present) when the output voltage obtained by the sensor is equal to or higher than a predetermined value, and detects that the toner is absent (developer is absent) when the output voltage is lower than the predetermined value. Note that the determination threshold for the presence of toner can be changed depending on the desired toner weight.

<Control unit>
Next, the control unit of the image forming apparatus A will be described with reference to the block diagram shown in FIG. Here, a control system related to the developing device 3 will be described in particular.

  As shown in FIG. 4, the CPU 70 (control means) is connected to the in-conveyance path sensor 14 and the in-developer sensor 16 via the toner detection unit 71. Further, a bottle drive motor 74, a conveyance path motor 75, and a developing device clutch 76 are connected via a drive control unit 72. Therefore, the CPU 70 can control the driving of the toner supply device 100 and the developing device 3 based on the detection results of the in-conveyance path sensor 14 and the developing device sensor 16.

  The CPU 70 is connected to a storage unit 73 including a ROM and a RAM, and can store various types of information.

<Developer supply device>
Next, the configuration of the toner replenishing device 100 as a developer replenishing device that replenishes toner to the developing device 3 will be described in detail. FIG. 5 is a side view and a plan view of the toner replenishing device 100 and the developing device 3. 5A is a right view of FIG. 2, and FIG. 5B is a top view of FIG.

  As shown in FIG. 5, the toner replenishing device 100 is provided in the vicinity of the developing device 3. The toner supply device 100 includes a toner bottle 50 and a bottle mounting portion 9 that rotatably supports the toner bottle 50. In addition, a rotation driving mechanism 10 is provided that receives a driving force from a bottle driving motor 74 (see FIG. 4) to rotate the toner bottle 50. Further, a transport path 60 for transporting toner from the toner bottle 50 to the developing device 3 is provided.

Inside the bottle mounting portion 9 is provided a pump 51 (pump member), which is a resin-made bellows-type variable volume type pump whose volume is variable with reciprocation. The pump 51 has a plurality of mountain folds and valley folds formed alternately and periodically. Then, the driving force received from the rotary drive mechanism 10 is converted into the reciprocating power of the pump 51, whereby compression and extension can be alternately repeated (stretched). In the present embodiment, the volume change amount when the pump 51 is expanded and contracted is set to 17 cm ³ (cc). A drive system for driving the pump 51 will be described later.

  The toner bottle 50 is a cylindrical member, and a spiral protrusion 50 a is formed on the inner peripheral surface so as to protrude inward of the toner bottle 50. Then, the toner is transported to the bottle mounting portion 9 side by the protrusion 50 a by being rotationally driven by the rotational drive mechanism 10, and then the toner is transported into the pump 51. The toner bottle 50 is detachably attached to the bottle mounting portion 9 (the apparatus main body of the developer supply device).

  FIG. 6 is a diagram for explaining the configuration of the pump 51. Here, FIG. 6A is a schematic cross-sectional view of the pump 51 in a state in which the pump 51 is extended as much as possible. FIG. 6B is a schematic cross-sectional view showing a state where the pump 51 is maximally contracted in use. FIG. 6C is a view of FIG. 6A viewed from above, and FIG. 6D is a view of FIG. 6B viewed from above.

  As shown in FIG. 6, the pump 51 includes a discharge port 52 for discharging the toner to the conveyance path 60. Then, the volume of the space including the toner bottle 50 is changed by repeatedly expanding and contracting at a predetermined cycle, the intake operation and the exhaust operation are repeated through the discharge port 52, and the toner is discharged from the discharge port 52 to the conveyance path 60.

  That is, the pump 51 is extended to the maximum volume (the state shown in FIGS. 6A and 6C) and contracted to the minimum volume (the states shown in FIGS. 6B and 6D). Repeat at a predetermined cycle. As a result, an air flow directed to the inside of the toner bottle 50 through the discharge port 52 and an air flow directed to the outside from the toner bottle 50 are repeatedly generated, and the toner is efficiently transferred from the discharge port 52 having a small diameter (about 2 mm in diameter) to the conveyance path 60. Let it drain. Further, the discharged toner is supplied to the developing device 3 through the conveyance path 60. That is, the driving (extension / contraction) of the pump 51 can be said to be a supply operation for supplying the toner to the developing device 3 via the conveyance path 60. The pump 51 is provided so that it does not rotate in the rotation direction of the cylindrical portion 57.

  Next, the drive system of the toner bottle 50 and the pump 51 will be described with reference to FIG.

  As shown in FIG. 6, the toner bottle 50 includes a gear portion 53 (drive receiving portion), and the toner bottle 50 rotates when the gear portion 53 is rotationally driven. In addition, the gear portion 53 is provided with a cam groove 55 having a groove on the entire periphery thereof. Then, by the cam mechanism including the cam groove 55, the rotational driving force for rotating the toner bottle 50 is converted into a force in the direction in which the pump 51 is reciprocated. As described above, the configuration in which the driving force for rotating the toner bottle 50 and the reciprocating motion of the pump 51 is received by the single gear portion 53 makes it possible to compare the toner bottle 50 with the case where two drive receiving portions are separately provided. The configuration of the drive input mechanism can be simplified.

  Specifically, a reciprocating member 54 (drive transmission member) is used as a member interposed for converting the rotational driving force into the reciprocating power of the pump 51. First, when the gear portion 53 receives rotational driving from the rotational drive mechanism 10, the cam groove 55 integrated with the gear portion 53 rotates. The cam groove 55 is engaged with an engaging protrusion 56 partially protruding from the reciprocating member 54. The reciprocating member 54 is fixed so that it does not rotate in the direction of rotation of the cylindrical portion 57 (allows a backlash to be allowed). Therefore, the rotation of the cam groove 55 causes the engagement projection 56 to reciprocate along the shape of the cam groove 55, whereby the reciprocating member 54 reciprocates, and the pump 51 is alternately expanded and contracted. repeat.

  In the present embodiment, a plurality of engaging protrusions 56 are provided to engage with the cam groove 55. Specifically, two engaging projections 56 are provided on the outer peripheral surface of the cylindrical portion 57 so as to face each other by about 180 °. However, at least one engagement protrusion 56 may be provided. However, since a moment is generated in the drive conversion mechanism or the like due to the drag force when the pump 51 is expanded or contracted, smooth reciprocation may not be performed. Therefore, it is preferable to provide a plurality so that the relationship with the shape of the cam groove 55 does not break. .

  The rotation of the toner bottle 50 is confirmed by providing a protrusion (not shown) on a part of the toner bottle 50 and using a photo interrupter type HP sensor (not shown). The protruding portion is installed so as to be detected by the HP sensor every half rotation of the toner bottle 50, and the pump 51 is configured to be driven (expanded) once every half rotation.

  The state in which the HP sensor detects the protrusion and the rotation of the toner bottle 50 is stopped is hereinafter referred to as a home position. Here, when the rotation of the toner bottle 50 is stopped at a position other than the home position, the pump 51 is stopped in a state where the pump 51 is extended or contracted. When the next rotational drive is started from here, the pump 51 cannot perform normal expansion and contraction, and the possibility of occurrence of toner discharge abnormality increases. Therefore, the rotation of the toner bottle 50 is controlled to stop at the home position.

  Next, the configuration of the transport path 60 will be described. FIG. 7 is a diagram illustrating a configuration of the conveyance path 60. Here, FIG. 7A is a cross-sectional view of the conveyance path 60, and FIG. 7B is a side view of the conveyance path 60.

  As shown in FIG. 7, the transport path 60 includes a transport path supply port 61 connected to the discharge port 52 (see FIG. 5). Further, the developing device 3 is provided with a conveying screw 13 (developer conveying means) for conveying the toner. Further, in the vicinity of the conveyance screw 13 and just below the conveyance path supply port 61, a sensor 14 in the conveyance path is provided. Further, a replenishing port 62 for replenishing toner to the developing device 3 is provided.

  Next, the toner conveyance operation of the conveyance path 60 will be described. First, toner is supplied into the conveyance path 60 from the conveyance path supply port 61. Thereafter, the driving screw 13 is rotated by receiving a driving force from the transport path motor 75 (see FIG. 4), so that the toner is transported to the supply port 62 side. When the toner is conveyed to the replenishing port 62, the toner is replenished from the replenishing port 62 to the developing device 3.

The toner used in the conveyance path 60 of the present embodiment has a bulk density of about 0.5 to 0.8 g / cm ^{3 in} an environment where the temperature is 20 to 25 ° C. and the humidity is 30 to 60%. Under this configuration, the diameter of the conveying screw 13 is preferably about 10 to 20 mm, the screw pitch is about 10 to 30 mm, and the screw rotation speed is preferably 100 to 200 rpm. Note that when the type of toner and the amount of toner supplied into the transport path are significantly changed, the configuration of the transport screw needs to be optimized as appropriate.

<Toner replenishment sequence>
Next, a toner supply sequence for supplying toner to the developing device 3 after replacement of the toner bottle 50 will be described.

  First, before explaining the sequence, a phenomenon called initial blockage in which toner is not discharged from the discharge port 52 even if the pump 51 is driven due to toner clogging at the initial time after replacement of the toner bottle 50 will be described.

  The state in which the toner is discharged from the toner bottle 50 varies depending on the storage state of the toner bottle 50. Here we define the conditions of normal storage and harsh logistics. The normal storage is a state in which the toner bottle 50 is left for 10 days at a temperature of 20 to 25 ° C. (room temperature) and a humidity of 40 to 60%. The severe distribution is a state where the toner bottle 50 is dropped about 1000 times from a height of 3 to 6 cm above the ground with the toner discharge side on which the pump 51 is disposed down, and vibration is applied.

  In normal storage, the toner is smoothly discharged immediately after the toner bottle 50 is replaced. However, in severe logistics, since the diameter of the discharge port 52 is often small, toner clogging is likely to occur. For this reason, even if the pump 51 is driven in the initial state, an idle shot in which the toner is not discharged occurs, and the toner is discharged after the idle shot is performed to some extent. This is a phenomenon of toner clogging called initial blockage. When the initial blockage occurs as described above, the toner replenishment time for replenishing the toner from the toner replenishing device 100 to the developing device 3 is prolonged.

  Therefore, in order to suppress such a prolonged toner replenishment time due to the initial blockage, toner replenishment is performed after the toner bottle 50 is replaced by a toner replenishment sequence described below. Hereinafter, the contents of the toner replenishment sequence will be specifically described with reference to the flowchart shown in FIG.

  As shown in FIG. 8, first, the CPU 70 detects that the toner bottle 50 has been replaced (S1). This starts the sequence.

  Next, the presence or absence of toner in the transport path 60 is determined by the transport path sensor 14 in the transport path 60 (S2).

  Next, when the absence of toner in the conveyance path 60 is detected, the pump 51 performs an operation (normal drive) in a normal replenishment operation (S3). Here, the normal drive means that the pump 51 is driven under the START and STOP conditions of the pump normal drive shown in FIG. That is, the pump 51 starts driving when the conveyance path sensor 14 detects the absence of toner, and stops driving when the HP sensor detects that the toner bottle 50 is half-rotated. That is, in the normal replenishment operation, the pump 51 expands and contracts once to perform the toner supply operation. The driving time when the pump 51 performs normal driving is 0.7 sec.

  Next, when the transport path sensor 14 detects the absence of toner although the pump 51 is normally driven (S4), +1 is added to the no-toner count and the result is stored in the RAM of the storage unit 73 (S5). Here, the time for the conveyance path sensor 14 to detect the presence or absence of toner is 0.5 sec.

  Next, it is determined whether the toner non-count is +10 or less (S6). Here, when the toner non-count is +10 or less, the pump 51 is normally driven again (S3), and the conveyance path sensor 14 detects the presence or absence of toner again (S4).

  By repeating this, when the toner non-count becomes larger than +10 (S6), it is determined as an initial blockage (S7), and the pump 51 is continuously driven as a supply operation that promotes the supply rather than the normal replenishment operation (S8). ). Here, the continuous drive means that the pump 51 is driven under the START and STOP conditions of the pump continuous drive shown in FIG. That is, the pump 51 starts continuous driving as an initial closing when the conveyance path sensor 14 continuously detects no-toner detection 10 times (continuously detected a predetermined number of times or more), and performs an expansion / contraction operation (normal toner supply operation) for a time. Run continuously without regular intervals. When the in-conveyance path sensor 14 detects the presence of toner (S9), the continuous driving is stopped (S10). That is, when the toner bottle 50 is newly attached and the conveyance path sensor 14 does not detect the toner continuously for a predetermined number of times or more after that, the CPU 70 starts the continuous driving and continues the pump for a longer time than the normal replenishment operation. 51 is set to supply toner.

  After the continuous drive is stopped, the drive condition of the pump 51 returns to the START and STOP conditions of the pump normal drive shown in FIG. Thereafter, the presence or absence of toner in the developing device 3 is determined by the developing device sensor 16 (S11). Here, when the absence of toner is detected, the in-conveyance path sensor 14 determines the presence or absence of toner (S2). When the absence of toner is detected, the pump 51 is normally driven (S3).

  In this state, since the initial blockage is eliminated by the continuous driving of the pump 51 described above, the toner is supplied to the conveyance path 60 by the normal driving of the pump 51. Accordingly, the in-conveyance path sensor 14 detects the presence of toner (S4), and the in-developer sensor 16 again determines the presence or absence of toner in the developer 3 (S11). This is repeated until the developer sensor 16 detects the presence of toner.

  Thereafter, when the in-developer sensor 16 detects the presence of toner, the toner absence count stored in the RAM of the storage unit 73 is cleared (S12), and the toner replenishment sequence is terminated (S13).

<Comparison of toner replenishment time>
Next, the toner supply time of the toner supply sequence of the present embodiment and the toner supply sequence of the comparative example are compared. In this comparison, it is assumed that idling occurs until the pump 51 is driven 80 times due to the initial blockage, and toner is discharged from the 81st time. Further, it is assumed that the developing device sensor 16 detects the presence of toner when the pump 51 is driven from the 81st time to the 100th time.

  A toner replenishment sequence of the comparative example is shown in the flowchart of FIG. The major difference from the toner supply sequence of this embodiment is as follows. That is, as shown in FIG. 10, even when the initial blockage occurs, the pump 51 is not continuously driven, the toner presence / absence determination by the in-conveyance path sensor 14 (S104), and the pump 51 normal drive (S103). Repeat step).

  Next, the toner replenishment time according to the toner replenishment sequence of the comparative example will be described first. As shown in FIG. 11A, in the sequence of the comparative example, the pump 51 is driven under normal conditions from the replacement of the toner bottle 50 until the toner supply operation is completed. Accordingly, the pump 51 driving 1 cycle time from the 1st to the 80th time when the pump 51 is idling occurs is 0.5 sec during which no toner is detected by the in-conveyance path sensor 14 during the pump 51 driving time 0.7 sec. The added time is 1.2 sec. That is, 1.2 sec × 80 times = 96 sec obtained by multiplying 1.2 sec by 80 pump driving times.

  Thereafter, the toner is discharged from the 81st to the 100th time, the developing device sensor 16 detects the presence of toner, and the toner supply sequence is stopped. The pump 51 driving cycle during this period is added to the pump driving time of 0.7 sec by adding 2.0 sec when the toner in the developer sensor 16 is not detected after the in-conveyance sensor 14 detects the presence of toner. 2.7 sec. Then, when 2.7 sec is multiplied by 20 times of pump driving, 2.7 sec × 20 times = 54 sec. Therefore, the toner replenishment time from the replacement of the toner bottle 50 to the completion of toner replenishment is 96 sec + 54 sec = 150 sec.

  Next, the toner replenishment time according to the toner replenishment sequence of this embodiment will be described. As shown in FIG. 11B, in the sequence of the present embodiment, the pump is driven 10 times under normal driving conditions after the replacement of the toner bottle 50 until it is determined as the initial blockage. The period of one cycle of pump driving during this period is 1.2 sec, and the time during this period is 12 sec at 1.2 sec × 10 times.

  Next, when it is determined as the initial blockage, the pump is continuously driven from the 11th to the 80th time when the toner is not discharged. That is, unlike the comparative example, since the detection time (0.5 sec) of the in-conveyance path sensor 14 is omitted, the time for one cycle of the pump drive during this period is 0.7 sec. Therefore, the time during this period is 0.7 sec × 70 times = 49 sec.

  Next, the toner is discharged from the 81st to the 100th time, the developer sensor 16 detects the presence of toner, and the toner supply sequence is stopped. The time during this period is 2.7 sec × 20 times = 54 sec as in the comparative example. Therefore, the toner replenishment time from the replacement of the toner bottle 50 to the completion of toner replenishment is 12 sec + 49 sec + 54 sec = 115 sec.

  From the above, it was found that the toner replenishment time can be shortened in the sequence of the present embodiment compared to the configuration in which the pump 51 is not continuously driven as in the sequence of the comparative example. In the present embodiment, toner clogging is eliminated by an existing configuration without providing a new member. Therefore, with the configuration of the present embodiment, it is possible to suppress the toner replenishment time from being prolonged due to the initial blockage with a simple configuration, and to shorten the toner replenishment time.

<Discharged toner amount>
Next, the amount of toner discharged to the conveyance path 60 by driving the pump 51 (supply operation by the pump 51) will be described.

  If toner is excessively supplied from the discharge port 52 near the in-transport path sensor 14 of the transport path 60, the toner may be clogged, resulting in failure or toner leakage. In this embodiment, the inner diameter of the pipe between the pump 51 and the conveying path 60 is 6 mm, the length is 30 mm, and the inner diameter of the conveying path 60 is 16.4 mm. The conveying screw 13 has a diameter of 15.4 mm and a core diameter of 6 mm, a screw pitch of 20 mm, and a screw rotation speed of 150 rpm. At this time, if 8.0 g or more of toner accumulates on the conveyance path 60, the above-described failure or toner leakage may occur.

  Here, in the present embodiment, the toner discharge amount when driven once during normal driving of the pump 51 is about 2.0 to 8.0 g, whereas the pump 51 is driven once during continuous driving after the initial closing. When the toner is discharged, the amount of discharged toner is 0.5 to 1.5 g. That is, the amount of toner supplied per toner supply operation by the pump 51 is smaller when the pump 51 is continuously driven than when the pump 51 is normally driven. In this way, the amount of toner discharged during continuous driving is small because the toner at the time of initial clogging is agglomerated toner, so the amount of toner discharged per pump is small compared to normal toner that is not agglomerated. It is to become.

  For this reason, if continuous driving is performed while the toner is in a normal state, the amount of toner discharged becomes excessive, which may cause the above-described failure or toner leakage. For example, if the pump 51 is continuously driven twice when the discharge amount is 8.0 g by one pump, about 16.0 g is deposited on the conveyance path 60, and the above problem may occur.

  On the other hand, since the aggregated toner after the initial blockage has a small amount of toner discharge, even if the toner is continuously driven, the situation in which the toner accumulates on the conveyance path 60 is not high enough to cause the above-described failure or toner leakage.

  Therefore, the pump 51 is normally driven immediately after the replacement of the toner bottle 50, and is continuously driven after the initial blockage determination, so that it is possible to suppress the occurrence of the above problem due to the accumulation of toner on the conveyance path 60. Further, since the pump 51 is normally driven immediately after the replacement of the toner bottle 50, it is possible to obtain more time for the toner remaining in the vicinity of the sensor 14 in the transport path before the replacement of the toner bottle 50 to be transported by the transport screw 13. It becomes difficult for toner to accumulate on the conveyance path 60.

  When the conveyance path sensor 14 detects the presence of toner during continuous driving of the pump 51, the toner bottle 50 is in the middle of rotation and is in a position other than the home position. Accordingly, after the presence of toner is detected, the toner bottle 50 rotates to the next home position with the continuous drive condition maintained. For this reason, the toner is discharged twice by the pump 51 during this time. However, since the aggregated toner has a small discharge amount per pump, it does not cause a failure in the conveyance path or toner leakage due to toner clogging.

(Second Embodiment)
Next, a second embodiment of the image forming apparatus A including the developer supply device according to the present invention will be described. About the part which overlaps with the said 1st Embodiment, the same drawing and the same code | symbol are attached | subjected and description is abbreviate | omitted.

  The toner replenishment sequence of this embodiment will be described with reference to the flowchart shown in FIG. As shown in FIG. 12, first, the CPU 70 detects that the toner bottle 50 has been replaced (S51). This starts the sequence.

  Next, the pump 51 is continuously driven (S52). Here, the continuous drive means that the pump 51 is driven under the START and STOP conditions of the pump continuous drive shown in FIG. That is, the pump 51 starts continuous driving when the replacement of the toner bottle 50 is detected. When the conveyance path sensor 14 detects the presence of toner (S53), the continuous driving stops (S54).

  Next, the presence or absence of toner in the developing device 3 is determined by the developing device sensor 16 (S55). If it is detected that toner is present, the presence or absence of toner is determined by the transport path sensor 14 (S56). If it is detected that toner is present, the pump 51 is normally driven (S57).

  At this time, the initial blockage is eliminated by the continuous driving in step S53. Accordingly, the conveyance path sensor 14 detects the presence of toner (S56), and the development unit sensor 16 detects the presence of toner again (S55), and this is repeated until the development unit sensor 16 detects the presence of toner. .

  Thereafter, when the developing device sensor 16 detects the presence of toner, the toner replenishment sequence is terminated (S59).

<Comparison of toner replenishment time>
Next, the toner supply time of the toner supply sequence of the present embodiment and the toner supply sequence of the comparative example are compared. In this comparison, it is assumed that the pump 51 is emptied until the first to 80th drive due to the initial blockage, and the toner is discharged from the 81st time. Further, it is assumed that the developing device sensor 16 detects the presence of toner when the pump 51 is driven from the 81st time to the 100th time.

  In the toner supply sequence of the comparative example, as described in the first embodiment, the time from the replacement of the toner bottle to the completion of the toner supply is 150 seconds (FIG. 14A).

  On the other hand, as shown in FIG. 14B, in the toner replenishment sequence of this embodiment, the pump is continuously driven after the toner bottle 50 is replaced until the conveyance path sensor 14 detects the presence of toner. Accordingly, the pump drive 1 cycle time from the 1st to the 80th time when the toner is not discharged is 0.7 sec. Therefore, the time during this period is 0.7 sec × 80 times = 56 sec.

  Next, the toner is discharged from the 81st to the 100th time, the developer sensor 16 detects the presence of toner, and the toner supply sequence is stopped. The time during this period is 2.7 sec × 20 times = 54 sec as in the comparative example. Therefore, the toner supply time from the replacement of the toner bottle 50 to the completion of toner supply is 56 sec + 54 sec = 110 sec.

  From the above, it was found that the toner replenishment time can be shortened in the sequence of this embodiment compared to the configuration in which the pump 51 is not continuously driven as in the sequence of the comparative example. In the toner supply sequence of the first embodiment, since the toner supply time is 115 seconds, it has been found that the toner supply time can be further shortened by executing the toner supply sequence of the present embodiment. In other words, it has been found that the configuration of this embodiment can suppress the toner replenishment time from being prolonged due to the initial blockage with a simple configuration and can shorten the toner replenishment time.

<Discharged toner amount>
Next, the amount of toner discharged to the conveyance path 60 by driving the pump 51 will be described.

  In the present embodiment, unlike the first embodiment, the inner diameter of the tube between the pump 51 and the conveying path 60 is 9 mm, the length is 30 mm, and the inner diameter of the conveying path 60 is 24.0 mm. The diameter of the conveying screw 13 is 23.0 mm, the core diameter is 9 mm, the screw pitch is 20 mm, and the screw rotation speed is 150 rpm. For this reason, when toner of 24.0 g or more accumulates on the conveyance path 60, there is a possibility that the conveyance path 60 may be broken or toner leakage may occur due to toner clogging.

  Here, in the toner supply sequence of the present embodiment, as described above, the pump is continuously driven as soon as the replacement of the toner bottle 50 is detected. However, even if the toner in the toner bottle 50 is in a normal state at this time, there is no problem due to toner clogging in the conveyance path 60.

  That is, as described in the first embodiment, the toner discharge amount per pump of the toner in the normal state is about 2.0 to 8.0 g. For this reason, when the pump 51 is continuously driven and then the conveyance path sensor 14 detects the presence of toner and is changed to the normal drive, even if the toner discharge by the pump 51 is performed twice continuously, about 16 Only 0.0 g of toner accumulates on the conveyance path 60. For this reason, only 24.0 g or less of toner that may cause a problem due to toner clogging accumulates, and no problem occurs.

  In this embodiment, the limit of toner accumulation that causes toner clogging is increased by changing the inner diameter of the conveyance path 60, but toner clogging in the conveyance path 60 can also be suppressed by other methods. That is, for example, a method for making the conveyance path 60 difficult to clog, or a method for improving the toner conveyance performance by changing the shape and rotation speed of the conveyance screw 13 may be adopted.

  In the first and second embodiments, the pump 51 is continuously driven to suppress the toner replenishment time from being prolonged due to the initial closing. However, the toner can be grasped in real time or close to the time when the toner is discharged by driving the pump 51, and the toner can be similarly configured so that it can be very close to the pump continuous driving condition under the normal pump driving condition. Prolonged supply time can be suppressed.

  Further, the total number of idle shots of the pump 51 is stored in the RAM of the storage unit 73, and the fact that the toner is not replenished by that number is reflected in the toner replenishment amount, so that the accuracy of the replenishment amount can be improved.

1 ... photosensitive drum (image carrier)
3 ... developer 50 ... toner supply device (developer supply device)
60 ... Conveying path 70 ... CPU (control means)
A: Image forming apparatus

Claims (7)

Supply means for supplying developer to a developing device in a detachable developer storage container for storing developer;
The supply means performs the supply operation of the developer, and when it is determined that the developer container is newly installed, the supply means continuously supplies a time for supplying the developer. Control means which can be set to a time longer than the time during which the means supplies developer;
A developer replenishing device comprising: A detecting means for detecting a developer in a conveyance path connecting the developer container and the developing device;
2. The development according to claim 1, wherein the control unit sets a long time for the supply unit to supply continuously when the detection unit does not detect the developer continuously for a predetermined number of times or more. Agent supply device.   3. The developer replenishing apparatus according to claim 2, wherein the control unit causes the supply unit to continuously supply the developer until the detection unit detects the developer.   4. The developer supply device according to claim 1, wherein the continuous supply repeats a supply operation at the time of image formation without a time interval. 5. .   5. The developer supply amount per supply operation when the continuous supply is performed is smaller than the developer supply amount when the supply operation is performed once. Developer replenisher.   6. The supply unit according to claim 1, wherein the supply unit includes a pump unit having a variable volume, and the supply operation is performed by changing a volume of the pump unit. Developer supply device. An image carrier;
A developing device for supplying a developer to the image carrier;
A developer replenishing device according to any one of claims 1 to 6,
An image forming apparatus comprising: