JP2016024251A - Developing device, image forming apparatus, and control method of developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a situation in which: when a developer sent out from an exit of a developer supply part is conveyed to an entrance side of a developing part along a lateral conveyance path extending in the lateral direction, even after developing processing and developer supply processing are interrupted, the developing processing and developer supply processing can be started from an initial state where the developer does not remain in the lateral conveyance path.SOLUTION: A control part 8 operates an intermediate lateral conveying part 121 in a lateral conveyance path 120 and a circulation conveyance part 132 in a developing tank 130 before starting for the first time after interruption of developing processing and developer supply processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic developing apparatus, an image forming apparatus including the same, and a control method for the developing apparatus.

  In general, an electrophotographic image forming apparatus includes an image carrier and a developing device. It is known that the developing device includes a developing unit that develops an electrostatic latent image on the image carrier and a developer replenishing unit that supplies a developer to the developing unit (see, for example, Patent Document 1). ).

  The developing unit develops the electrostatic latent image on the image carrier by supplying the developer from a developing tank to the image carrier. The developer replenishing section operates when the amount of the developer in the developing tank decreases.

  In addition, when the developer outlet in the developer replenishing unit and the developer inlet in the developing unit are at different positions in the horizontal direction, the developing device may further include an intermediate lateral conveying unit. The intermediate lateral transport unit transports the developer fed from the outlet of the developer replenishing unit to the inlet side of the developing unit along a lateral transport path extending in the lateral direction.

  As the developer replenishing section and the intermediate lateral transport section operate, the developer in the developer replenishing section is replenished to the developing section through the intermediate lateral transport section.

JP 2008-129357 A

  By the way, in the developing device, in order to stabilize the development quality, it is desirable that the developer replenishment process is started every time under a certain initial state where the developer does not remain in the lateral conveyance path.

  On the other hand, in the developing device, when the development process and the developer supply process are performed in parallel, the development process and the developer supply process may be interrupted without being completed due to some factor. The cause of the interruption is, for example, that an error such as a recording sheet jam has occurred, or that a forced stop operation such as power-off has been performed.

  When the development process and the developer replenishment process are interrupted, the intermediate horizontal conveyance unit stops while the developer remains in the horizontal conveyance path. In this case, when the development process and the developer replenishment process are first started after being interrupted, the developer remains in the lateral conveyance path. This is not preferable for stabilizing the development quality.

  It is an object of the present invention to interrupt the development process and the developer replenishment process when the developer sent from the outlet of the developer replenishment part is transported to the entrance side of the development part along the lateral transport path extending in the lateral direction. It is another object of the present invention to provide a developing device, an image forming apparatus, and a developing device control method capable of starting development processing and developer replenishment processing from an initial state where no developer remains in the lateral conveyance path.

  A developing device according to one aspect of the present invention includes a developer replenishing unit, an intermediate lateral conveyance unit, a developing unit, a developer amount sensor, a development execution control unit, a developer replenishment control unit, and before development resumption. A processing control unit. The developer replenishing portion is a portion that feeds the developer from a replenishing container that accommodates the developer. The intermediate lateral transport unit is a part that transports the developer fed from the developer replenishing unit to an outlet of the lateral transport path along a lateral transport path extending in the lateral direction. The developing unit includes a circulation conveyance unit and a developing roller. The circulation conveyance unit circulates the developer in a developer tank that accumulates the developer sent out from the outlet of the horizontal conveyance path. The developing roller supplies the developer from the developing tank to the image carrier. The developer amount sensor is a sensor that detects the amount of the developer in the developer tank. The development execution control unit is a control unit that executes a development process for developing the electrostatic latent image on the image carrier by operating the circulation conveyance unit and the development roller. The developer replenishment control unit controls the developer replenishment unit and the intermediate lateral transport unit when the detection result of the developer amount sensor satisfies a predetermined shortage condition when the development process is being performed. It is a control part which performs a developer replenishment process by operating. The development restart pre-processing control unit is a control unit that operates the intermediate lateral conveyance unit and the circulation conveyance unit before starting the first after the development process and the developer supply process are interrupted.

  An image forming apparatus according to another aspect of the present invention includes an image carrier and the developing device according to one aspect of the present invention.

  A control method for an image forming apparatus according to another aspect of the present invention is a control method for a developing device including the developer replenishing unit, the intermediate lateral conveyance unit, the developing unit, and the developer amount sensor. . The present control method includes a development execution control step, a developer replenishment control step, and a development resumption pretreatment control step. The development execution control step is a step of executing a development process for developing the electrostatic latent image on the image carrier by operating the circulation conveyance unit and the development roller. In the developer replenishment control step, when the detection result of the developer amount sensor satisfies a predetermined shortage condition while the development process is being performed, the developer replenishment unit and the intermediate lateral conveyance unit are This is a step of executing the developer replenishment process by operating. The pre-development pre-processing control step is a step of operating the intermediate horizontal conveyance unit and the circulation conveyance unit before starting the first after the development processing and the developer replenishment processing are interrupted.

  According to the present invention, the development process and the developer replenishment process are interrupted when the developer fed from the outlet of the developer replenishment section is transported to the entrance side of the development section along the lateral transport path extending in the lateral direction. Even later, it is possible to provide a developing device, an image forming apparatus, and a control method for the developing device that can start the development processing and the developer replenishment processing from the initial state where the developer does not remain in the lateral conveyance path.

FIG. 1 is a configuration diagram of an image forming apparatus including a developing device according to an embodiment of the present invention. FIG. 2 is a block diagram of control-related equipment of the developing device according to the embodiment of the present invention. FIG. 3 is a flowchart showing an example of a development execution control process in the developing device according to the embodiment of the present invention. FIG. 4 is a flowchart showing an example of a developer replenishment control process in the developing device according to the embodiment of the present invention. FIG. 5 is a flowchart showing an example of a post-development processing control process in the developing device according to the embodiment of the present invention. FIG. 6 is a flowchart illustrating an example of the pre-development pre-processing control process in the developing device according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: It does not have the character which limits the technical scope of this invention.

[Configuration of Image Forming Apparatus 10]
First, the configuration of the developing device 43 according to the embodiment of the present invention and the image forming apparatus 10 including the same will be described with reference to FIGS. The image forming apparatus 10 is an electrophotographic image forming apparatus. As shown in FIG. 1, the image forming apparatus 10 includes a sheet supply unit 2, a sheet conveying unit 3, an image forming unit 4, an optical scanning unit 5, a fixing unit 6, a developer amount sensor 800, and a control in a casing 100. Part 8 and the like.

  The image forming apparatus 10 is, for example, a printer, a copier, a facsimile machine, or a multifunction machine. The multifunction machine has both the printer function and the copier function.

  The sheet supply unit 2 includes a sheet receiving unit 21 and a sheet sending unit 22. The sheet receiving portion 21 is configured to be able to stack a plurality of recording sheets 9. The recording sheet 9 is a sheet-like image forming medium such as paper, coated paper, postcard, envelope, and OHP sheet.

  The sheet feeding unit 22 rotates in contact with the recording sheet 9 to send the recording sheet 9 from the sheet receiving unit 21 toward the conveyance path 30.

  The sheet conveyance unit 3 includes a conveyance roller 31. The conveyance roller 31 conveys the recording sheet 9 supplied from the sheet supply unit 2 toward the image forming unit 4, and further, the recording sheet 9 after image formation is discharged from the discharge port of the conveyance path 30. The sheet is discharged onto the discharge tray 101.

  The image forming unit 4 forms an image on the surface of the recording sheet 9 that is supplied from the sheet feeding unit 22 and is moving along the conveyance path 30. The image forming unit 4 includes a drum-shaped photoconductor 41, a charging device 42, a developing device 43, a transfer device 45, a charge eliminating device 46, a cleaning device 47, and the like. The photoreceptor 41 is an example of an image carrier.

  The photoconductor 41 rotates and the charging device 42 charges the surface of the photoconductor 41 uniformly. Further, an electrostatic latent image is written on the surface of the photosensitive member 41 charged by scanning the laser beam with the optical scanning unit 5.

  The developing device 43 develops the electrostatic latent image on the photoreceptor 41 with a developer. Further, the transfer device 45 transfers the image (developer image) on the surface of the photoconductor 41 to the recording sheet 9 moving on the conveyance path 30. For example, the developer is a one-component developer containing toner or a two-component developer containing toner and carrier.

  Further, the neutralization device 46 neutralizes the surface of the photoconductor 41 after image transfer, and the cleaning device 47 removes the developer remaining on the photoconductor 41 surface.

  The fixing unit 6 sandwiches the recording sheet 9 on which an image is formed between a fixing roller 61 including a heater 610 such as a halogen heater and a pressure roller 62, and sends the recording sheet 9 to a subsequent process. As a result, the fixing unit 6 heats the image of the developer on the recording sheet 9 and fixes the image on the recording sheet 9.

[Details of development equipment]
The developing device 43 includes a developer supply unit 11, a developer intermediate transport unit 12, and a developing unit 13. In the present embodiment, the developing device 43 also includes a portion for controlling the developer replenishing unit 11, the developer intermediate transport unit 12, and the developing unit 13 in the control unit 8.

  As shown in FIG. 1, the developing unit 13 includes a developing tank 130, a developing roller 131, and a circulation conveyance unit 132. The developer tank 130 is a container for storing the developer supplied from the developer supply unit 11 via the developer intermediate transport unit 12.

  The developing unit 13 develops the electrostatic latent image on the photoconductor 41 by supplying the developer in the developing tank 130 to the photoconductor 41. The circulation conveyance unit 132 rotates in the developing tank 130 to convey the developer to the periphery of the developing roller 131 while circulating in the developing tank 130. The circulation conveyance unit 132 is also a stirring unit that stirs the developer in the developing tank 130. For example, the circulation conveyance unit 132 includes a plurality of screw-type conveyance members that are rotating bodies each having a rotation shaft portion and a spiral blade portion formed around the rotation shaft portion.

  When an image forming job is executed, the developing roller 131 develops the electrostatic latent image on the surface of the photoconductor 41 with the developer by supplying the developer to the surface of the photoconductor 41. The developing roller 131 may be referred to as a developing sleeve.

  The developer supply unit 11 is detachably attached to the main body (inside the casing 100) of the image forming apparatus 10 including the developing unit 13.

  The developer supply unit 11 has a supply container 110 and a developer delivery unit 111. The replenishing container 110 is a container for storing the developer. The developer delivery unit 111 rotates to deliver the developer from the supply container 110 to the developer intermediate transport unit 12.

  For example, it is conceivable that the developer delivery unit 111 is a screw-type conveying member that is a rotating body having a rotating shaft portion and a spiral blade portion formed around the rotating shaft portion.

  The developer intermediate transport unit 12 includes an intermediate lateral transport unit 121. The intermediate lateral transport unit 121 transports the developer fed from the developer replenishing unit 11 to the outlet 1201 of the lateral transport path 120 along the lateral transport path 120 extending in the lateral direction. An inlet 1200 of the lateral conveyance path 120 and an outlet 1101 of the developer replenishing unit 11 communicate with each other in the vertical direction. Similarly, the outlet 1201 of the lateral conveyance path 120 and the inlet 1300 of the developing unit 13 communicate in the vertical direction.

  The outlet 1101 of the developer supply unit 11 is an outlet of the developer in the supply container 110. An inlet 1300 of the developing unit 13 is an inlet of the developer in the developing tank 130.

  The horizontal conveyance path 120 is formed of a cylindrical member that is supported in a state where the center line is along the horizontal direction. The horizontal direction includes a horizontal direction (straight side direction) and a direction slightly inclined with respect to the horizontal direction, for example, a direction forming an acute angle of less than 45 degrees with respect to the horizontal direction (oblique horizontal direction).

  The intermediate lateral transport unit 121 transports the developer in the lateral direction by rotating in the lateral transport path 120. The intermediate lateral transport unit 121 transports the developer from the entrance 1200 side of the lateral transport path 120 to the exit 1201. In other words, the developer replenishing unit 11 replenishes the developer from the replenishing container 110 to the developing tank 130 via the developer intermediate transport unit 12.

  For example, it is conceivable that the intermediate lateral conveying unit 121 is a screw-type conveying member that is a rotating body having a rotating shaft portion and a spiral blade portion formed around the rotating shaft portion.

  The photosensitive member 41, the developing roller 131, the circulation conveyance unit 132, and the intermediate horizontal conveyance unit 121 are rotationally driven by the development driving unit 14. For example, the development driving unit 14 includes a motor and a gear mechanism that transmits the rotational force of the motor to the photoconductor 41, the developing roller 131, the circulation conveyance unit 132, and the intermediate lateral conveyance unit 121. .

  The developer delivery unit 111 of the developer supply unit 11 is driven by a supply drive unit 15. For example, the replenishment drive unit 15 can release the gear mechanism that transmits the rotational force of the drive source (motor) of the development drive unit 14 to the developer delivery unit 111, and the connection between the gear mechanism and the drive source. It has a clutch.

  The developer amount sensor 800 is a sensor that detects the amount of the developer in the developer tank 130. For example, it is conceivable that the developer amount sensor 800 is a magnetic permeability sensor that detects magnetism that changes in accordance with the amount of the developer in the developer tank 130. In addition, the developer amount sensor 800 may be a piezoelectric vibration sensor that outputs a signal that changes according to the amount of the developer (powder) present in the vicinity. It is also conceivable that the developer amount sensor 800 is a transmissive optical sensor.

  The control unit 8 controls various devices included in the image forming apparatus 10. For example, the control unit 8 controls the replenishment drive unit 15 according to the detection result of the developer amount sensor 800 and controls the development drive unit 14 according to the status of the image forming job. In the present embodiment, at least a portion of the control unit 8 that controls the development drive unit 14 and the replenishment drive unit 15 forms a part of the development device 43.

  As shown in FIG. 2, the control unit 8 includes an MPU (Micro Processor Unit) 81, a memory 82, a signal interface 83, a drive circuit 84, and the like.

  The MPU 81 is a processor that executes various arithmetic processes. The control unit 8 performs overall control of the image forming apparatus 10 by the MPU 81 executing various control programs Pr1 to Pr4 stored in advance in the memory 82.

  The memory 82 is a nonvolatile storage unit in which information such as the control programs Pr1 to Pr4 for causing the MPU 81 to execute various processes is stored in advance. Further, the memory 82 is also a storage unit that can read and write various data D1, D2 by the MPU 81. It is also conceivable that a memory for storing the control programs Pr1 to Pr4 and a memory for recording the data D1 and D2 are provided separately.

  The signal interface 83 is an interface circuit that relays signal transfer between the MPU 81 and the sensors and control target devices. The MPU 81 inputs detection signals (measurement signals) from various sensors including the developer amount sensor 800 through the signal interface 83.

  Further, the MPU 81 outputs a control signal to the drive circuit 84 through the signal interface 83, thereby controlling the development drive unit 14, the replenishment drive unit 15, the charging device 42, the charge removal device 46, and the like. The drive circuit 84 operates or stops controlled devices such as the development drive unit 14 and the replenishment drive unit 15 in accordance with a control signal from the MPU 81.

  By the way, in the developing device 43, the developer replenishing process for replenishing the developer from the replenishing container 110 to the developing tank 130 in order to stabilize the development quality is performed each time the developer is in the lateral conveyance path 120. It is desirable to start under certain initial conditions that do not remain in the

  On the other hand, in the developing device 43, the developer replenishing unit 11 operates when the developing process is being performed, and the intermediate lateral transport unit 121 remains in a state where the developer remains in the lateral transport path 120. May stop.

  For example, in the developing device 43, when the developing process for developing the electrostatic latent image on the photoconductor 41 and the developer replenishing process are performed in parallel, the developing process and the developer are caused by some factor. The replenishment process may be interrupted without being completed. The cause of the interruption is, for example, that an error such as a jam of the recording sheet 90 has occurred, or that a forced stop operation such as power-off has been performed.

  When the development process and the developer replenishment process are interrupted, the intermediate horizontal conveyance unit 121 is stopped while the developer remains in the horizontal conveyance path 120. In this case, the developer remains in the lateral conveyance path 120 when the development process and the developer supply process are first started after being interrupted. This is not preferable for stabilizing the development quality.

  However, when the developer fed from the outlet 1101 of the developer supply unit 11 is transported to the inlet 1300 side of the developing unit 13 along the lateral transport path 120 extending in the lateral direction, the control unit 8 It is conceivable to execute a development re-starting pre-processing control step which will be described later. Thereby, after the development process and the developer supply process are interrupted, the development process and the developer supply process may be started under an initial state where the developer does not remain in the lateral conveyance path 120. it can.

  Further, even when the development processing and the developer replenishment processing are completed, there is a possibility that a long time elapses with the developer remaining in the lateral conveyance path 120. In this case, the developer aggregates or fails to be charged in the lateral conveyance path 120, which may cause clogging of the developer conveyance path and development failure.

  However, when the developer fed from the outlet 1101 of the developer supply unit 11 is transported to the inlet 1300 side of the developing unit 13 along the lateral transport path 120 extending in the lateral direction, the control unit 8 It is conceivable to perform a post-development processing control step described later. Thereby, it is possible to prevent the developer from remaining in the lateral conveyance path 120.

  Hereinafter, an example of a method for controlling the developing device 43 will be described with reference to the flowcharts of FIGS. In the following description, S1, S2,... Represent processing procedure identification codes. The processing of the control unit 8 shown below is realized by the MPU 81 executing a control program stored in the memory 82.

[Development execution control process]
First, an example of the development execution control process will be described with reference to FIG. FIG. 3 is a flowchart showing an example of the development execution control process executed by the control unit 8. The control unit 8 executes the development execution control process shown in FIG. 3 when an image forming job is generated and when the processing of the image forming job is resumed after being interrupted.

<Process S1>
In the development execution control step, first, the control unit 8 is in a state after the previous development execution control step is interrupted in the middle, and thereby the previous developer replenishment process is interrupted in the middle. It is determined whether or not there is. That is, the control unit 8 determines whether or not the current state is a state in which the development process is started first after the development process and the developer supply process are interrupted.

  In step S <b> 1, the control unit 8 refers to the replenishment record data recorded in the memory 82 to determine whether or not the previous developer replenishment process has been interrupted. The replenishment record data will be described later.

  If the previous developer replenishment process is not interrupted, the control unit 8 skips the next step S2 and shifts the process to step S3 described later.

<Process S2>
When the previous developer replenishment process is interrupted, the control unit 8 waits until a process control process before resuming development described later is completed, and then shifts the process to process S3 described later.

<Process S3>
In step S <b> 3, the control unit 8 operates the developing drive unit 14 and operates the charge removal device 46 and the charging device 42. At this time, the control unit 8 also executes a process of writing the electrostatic latent image on the photoconductor 41 by controlling the optical scanning unit 5. As a result, the circulation conveyance unit 132, the developing roller 131, and the photosensitive member 41 are operated, and the developing process corresponding to the content of the image forming job is started. In the present embodiment, when the circulating transport unit 132 is operated, the intermediate lateral transport unit 121 is also operated in conjunction therewith.

<Steps S4 and S5>
Further, the control unit 8 calculates a printing rate for each predetermined unit in the developing process, and temporarily stores the calculation result (S4). For example, the control unit 8 calculates the printing rate for each image formation on one recording sheet 9. The printing rate is the ratio of the area of the actually developed portion to the area of the image forming range. The controller 8 repeats the calculation of the printing rate for each predetermined unit until the development processing corresponding to the image forming job is completed (S5).

<Step S6>
When the development processing corresponding to the image forming job is completed, the control unit 8 calculates a control printing rate from the printing rate calculated in step S4. Further, the control unit 8 records the calculated control printing rate D 1 in the memory 82.

  The control printing rate D1 is a representative value of the printing rate for each unit area in a series of the developing processes corresponding to the image forming job. For example, the control printing rate D1 is an average value or an integrated value of the plurality of printing rates calculated in step S4.

  Steps S1 to S6 shown above execute the development processing for developing the electrostatic latent image on the photosensitive member 41 (image carrier) by operating the circulation conveyance unit 132 and the developing roller 131. It is an example of an execution control process. The development execution control step is realized by the MPU 81 executing the development execution control program Pr1. The MPU 81 that executes the development execution control program Pr1 is an example of a development execution control unit.

<Step S7>
When the development processing corresponding to the image forming job is completed, the control unit 8 further executes a post-development processing control step to be described later. In the post-development processing control step, the control unit 8 stops the development driving unit 14.

[Developer supply control process]
Next, an example of the developer supply control process will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the developer replenishment control process executed by the control unit 8. For example, the controller 8 executes the developer replenishment control process shown in FIG. 4 when the image forming job is generated and when the processing of the image forming job is resumed after being interrupted. In this case, the development execution control process (S1 to S6) and the developer supply control process are executed in parallel.

<Step S11>
In the developer replenishment control step, the controller 8 determines whether or not the current state is a state after the previous developer replenishment process is interrupted in the middle, as in step S1. That is, the control unit 8 determines whether or not the current state is a state in which the development process and the developer supply process are first started after the development process and the developer supply process are interrupted.

  If the previous developer replenishment process is not interrupted, the control unit 8 skips the next step S12 and shifts the process to step S13, which will be described later.

<Step S12>
When the previous developer replenishment process is interrupted, the control unit 8 shifts the process to step S13 to be described later after executing the development resumption pre-processing control step to be described later.

<Step S13>
In step S13, the controller 8 determines whether or not the detection result of the developer amount sensor 800 satisfies a predetermined shortage condition as needed.

  For example, the shortage condition is that the developer amount sensor 800 detects less than a predetermined appropriate lower limit amount. The state where the shortage condition is satisfied is a state where the amount of the developer in the developing tank 130 reaches a minimum amount necessary for proper development.

  It is also conceivable that the shortage condition may be adopted such that the state where the developer amount sensor 800 detects less than the appropriate lower limit amount continues for a predetermined period.

<Step S14>
When the detection result of the developer amount sensor 800 satisfies the shortage condition, the control unit 8 refers to the control printing rate D 1 recorded in the memory 82. Further, the control unit 8 sets a replenishment time according to the control printing rate D1.

  In step S14, the control unit 8 sets the replenishment time to a longer time when the control printing rate is higher than when the control printing rate is low. For example, the control unit 8 sets the replenishment time having a positive linear correlation with the control printing rate D1.

<Step S15>
Further, the control unit 8 records the replenishment record data D2 indicating that the developer replenishment process has been practically “started” in the memory 82. As will be described later, the replenishment record data D2 is data indicating whether the developer replenishment process is completed or interrupted in the middle.

<Step S16>
Further, the control unit 8 operates the replenishment driving unit 15 and continues its operation until the replenishment time elapses. Thereby, the developer replenishing section 11 operates until the replenishment time elapses after the shortage condition is satisfied. This step S16 is executed in parallel with steps S3 to S5 in the development execution processing step. Therefore, in step S <b> 16, the control unit 8 operates the developer replenishing unit 11 and also operates the intermediate lateral conveyance unit 121, the circulation conveyance unit 132, and the developing roller 131.

<Steps S17 and S18>
When the replenishment time elapses, the control unit 8 stops the replenishment drive unit 15 (S17), and further records the replenishment record data D2 indicating that the developer replenishment process is “completed” in the memory 82. (Update. Thereby, the developer replenishment control process ends.

  The fact that the record content of the replenishment record data D2 at the start of the development process is “completed” means that the developer replenishment process is executed during the previous development process, and the developer replenishment process is performed. Indicates that is complete. On the other hand, the recorded content of the replenishment record data D2 at the start of the development process is “start”, which means that the developer replenishment process is executed during the previous development process, and the developer Indicates that the supply process has been interrupted.

  Accordingly, in steps S1 and S11 described above, the control unit 8 refers to the replenishment record data D2 to determine whether or not the previous developer replenishment process has been interrupted.

  Steps S13 to S18 shown above are an example of the developer supply control step. The developer supply control process is realized by the MPU 81 executing the developer supply control program Pr2. The MPU 81 that executes the developer supply control program Pr2 is an example of a developer supply control unit.

  In the developer supply control step, the control unit 8 (the developer supply control unit) operates the developer supply unit 11 when the detection result of the developer amount sensor 800 satisfies the shortage condition (S13). , S14).

  In the developer replenishment control step, the control unit 8 (the developer replenishment control unit) is more likely to develop the developer replenishment unit 11 when the control printing rate representing the size of the printing rate is higher than when the control printing rate is low. And the said intermediate horizontal conveyance part 121 is operated for a longer time (S14, S16). In this case, the operation speed of the developer supply unit 11 (the developer delivery unit 111) is constant.

  That is, the control unit 8 (the developer replenishment control unit) is configured to operate the developer replenishment unit under an operating condition in which the amount of the developer delivered is higher when the printing rate in the development process is higher than when the printing rate is low. 11 is operated (S14, S16). Thereby, even when the detection accuracy of the developer amount sensor 800 is not so high, the amount of the developer in the developer tank 130 can be stably maintained within an appropriate range.

[Development post-processing control process]
Next, an example of the post-development processing control step (S7) will be described with reference to FIG. FIG. 5 is a flowchart showing an example of the post-development processing control step executed by the control unit 8. The post-development process control step is executed subsequent to the development execution control step (S1 to S6).

<Step S21>
In the post-development process control step, first, the controller 8 determines whether or not the replenishment record data D2 is recorded in the memory 82. The controller 8 shifts the process to step S22 when the replenishment record data D2 is recorded, and shifts the process to step S25 when it is not recorded.

  The fact that the replenishment record data D2 is recorded in the memory 82 indicates that the control unit 8 has operated the developer replenishment unit 11 during the development process. Accordingly, the fact that the replenishment record data D2 is not recorded indicates that the developer replenishment unit 11 (the developer delivery unit 111) has not been operated when the development process is being performed.

<Step S22>
When the replenishment record data D2 is recorded, the control unit 8 refers to the control printing rate D1 recorded in the memory 82. Further, the control unit 8 sets an extension time corresponding to the control printing rate D1.

  In step S22, the control unit 8 sets the extended time to a longer time when the control printing rate is higher than when the control printing rate is low. For example, the control unit 8 sets the extension time having a positive linear correlation with respect to the control printing rate D1.

<Step S23>
Then, the control unit 8 continues the operation of the development drive unit 14 following the development execution control step until the extended time elapses, and also continues the operations of the charge removal device 46 and the charging device 42. .

<Step S24>
When the extended time elapses, the control unit 8 erases the replenishment record data D2 in the memory 82.

<Step S25>
Further, when the extension time has elapsed (YES in S23), the control unit 8 stops the development driving unit 14 and stops the charge removal device 46 and the charging device 42. As a result, the intermediate lateral conveyance unit 121, the developing unit 13, and the photoconductor 41 are stopped, and the post-development processing control step (S5: S21 to S25) is completed. In addition, when the replenishment record data D2 is not recorded (NO in S21), the control unit 8 promptly does not wait for the extension time to elapse and the development driving unit 14, the charge removal device 46, and the charging The device 42 is stopped.

  Steps S21 to S25 shown above are an example of the post-development processing control step. The post-development process control step is realized by the MPU 81 executing the post-development process control program Pr3. The MPU 81 that executes the post-development processing control program Pr3 is an example of a post-development processing control unit.

  In the post-development process control step, the control unit 8 (the post-development process control unit) stops after continuously operating the intermediate lateral conveyance unit 121 and the developing unit 13 even after the development process is completed. (S23, S25). Thereby, it is possible to prevent the developer from remaining in the lateral conveyance path 120. As a result, it is possible to prevent the occurrence of inconveniences such as aggregation of the developer or charging failure, and further to prevent clogging of the developer transport path and development failure due to these inconveniences.

  The control unit 8 (the post-development processing control unit) passes a longer time after the end of the development process when the control printing rate indicating the size of the printing rate is higher than when the control printing rate is low. Until then, the intermediate lateral conveyance section 121 and the developing section 13 are continuously operated (S22, S23, S25). In this case, the operation speed of the developer supply unit 11 (the developer delivery unit 111) is constant.

  That is, the control unit 8 (the post-development process control unit) increases the amount of the developer delivered after the development process is finished when the printing rate in the development process is higher than when the printing rate is low. The intermediate lateral conveyance unit 121 is operated under operating conditions. Thereby, when the amount of the developer fed from the developer replenishing unit 11 is controlled according to the printing rate, the extension process (S23) of the operations of the intermediate lateral conveying unit 121 and the developing unit 13 is performed. It is executed without excess or deficiency.

  Further, the control unit 8 (the post-development processing control unit) performs the development process only when the developer supply unit 11 is operated by the developer supply control step while the development process is being performed. Even after the completion, the intermediate lateral conveying section 121 and the developing section 13 are continuously operated and then stopped (S21, S23, S25). As a result, it is possible to prevent deterioration of the developer and wasteful power consumption caused by performing the extension processing (S23) of the intermediate lateral conveyance unit 121 and the developing unit 13 more than necessary.

[Development pre-processing control process]
Next, an example of the development resumption pretreatment control step (S12) will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of the pre-development pre-processing control process executed by the control unit 8. The pre-development pre-processing control step is executed before starting for the first time after the development processing and the developer replenishment processing are interrupted (S12).

<Step S31>
In the development resumption pretreatment control step, the control unit 8 refers to the control printing rate D1 recorded in the memory 82. At this time, the control printing rate D1 recorded in the memory 82 represents the printing rate in the previous development processing that was interrupted. Further, the control unit 8 sets a preprocessing time corresponding to the control printing rate D1.

  In step S32, the control unit 8 sets the preprocessing time to a longer time when the control printing rate is higher than when the control printing rate is low. For example, the control unit 8 sets the preprocessing time having a positive linear correlation with respect to the control printing rate D1.

<Process S32>
Further, the control unit 8 operates the development driving unit 14 and continues the operation until the preprocessing time elapses. As a result, the intermediate lateral conveyance unit 121 and the circulation conveyance unit 132 operate. Therefore, the developer remaining in the lateral conveyance path 120 is conveyed into the developing tank 130 and further stirred in the developing tank 130.

  In step S <b> 32, the control unit 8 does not execute the process of writing the electrostatic latent image on the photoconductor 41. Furthermore, in step S32, the control unit 8 does not operate the replenishment drive unit 15. Therefore, step S32 is executed before the development process and the developer supply process are performed.

  In this embodiment, the cleaning device 47 removes the developer remaining on the photoconductor 41 by rotating the photoconductor 41 in step S32. Further, in the present embodiment, in step S32, the developing roller 131 rotates, but the development process is not executed because the electrostatic latent image is not written.

<Step S33>
When the preprocessing time has elapsed, the control unit 8 erases the replenishment record data D2 in the memory 82.

<Step S34>
Further, when the preprocessing time has elapsed, the control unit 8 stops the development driving unit 14. As a result, the intermediate lateral conveyance unit 121 and the circulation conveyance unit 132 are stopped, and the pre-development reprocessing control process (S12: S31 to S34) is completed. The photosensitive member 41 and the developing roller 131 are also stopped.

  Steps S31 to S34 shown above are an example of the pre-restart processing control process. The development resumption pretreatment control process is realized by the MPU 81 executing the development resumption pretreatment control program Pr4. The MPU 81 that executes the development resumption preprocessing control program Pr4 is an example of a development resumption pretreatment control unit.

  In the pre-development pre-processing control step, the control unit 8 operates the intermediate horizontal conveyance unit 121 and the circulation conveyance unit 132 before starting the first after the development processing and the developer replenishment processing are interrupted. (S32). Thereby, even when the development process and the developer supply process are interrupted, the development process and the developer supply process are started under an initial state in which the developer does not remain in the lateral conveyance path 120 thereafter. can do. As a result, the development quality is stabilized.

  In addition, the control unit 8 is configured under the operating condition in which the developer delivery amount is increased when the printing rate (the control printing rate D1) in the previous development processing that has been interrupted is higher than when the printing rate is low. The intermediate horizontal conveyance unit 121 is operated (S31, S32).

  More specifically, the control unit 8 starts first when the development process and the developer replenishment process are interrupted when the printing rate in the previous development process is interrupted is higher than when the printing rate is low. Before the operation, the intermediate horizontal conveyance unit 121 and the circulation conveyance unit 132 are operated for a longer time (S31, S32). In this case, the operation speeds of the intermediate lateral conveyance unit 121 and the circulation conveyance unit 132 are constant.

  When the amount of the developer delivered from the developer supply unit 11 is controlled according to the printing rate, the pre-processing time is set according to the printing rate, so that the pre-development pre-processing control is performed. The operations (S32) of the intermediate horizontal conveyance unit 121 and the circulation conveyance unit 132 in the process are executed without excess or deficiency. As a result, it is possible to prevent the developer from being deteriorated and wasteful power consumption due to the operations of the intermediate lateral conveyance unit 121 and the circulation conveyance unit 132 being performed more than necessary.

  In the present embodiment, the developer feed amount in the developer replenishing unit 11 (the developer delivery unit 111), the intermediate lateral transport unit 121, and the circulation transport unit 132 is determined not by the operation speed but by the operation time. Be controlled. In this case, the developer feed amount can be adjusted by the development drive unit 14 and the replenishment drive unit 15 configured by a simple mechanism.

[Other application examples]
The developer feed amount in the developer replenishing unit 11 and the intermediate lateral transport unit 121 adjusted according to the printing rate changes the operating speed of each of the developer replenishment unit 11 and the intermediate lateral transport unit 121. It is considered that it is adjusted by.

  In the developer replenishment control step (S13 to S17), it is conceivable that the control unit 8 records the operation time of the developer replenishment unit 11 in the memory 82. In step S22, the control unit 8 may set the extension time corresponding to the recorded operation time. Similarly, in step S31, it is conceivable that the control unit 8 sets the preprocessing time corresponding to the recorded operation time.

  The developing device 43 may include an intermediate conveyance driving unit that drives the intermediate horizontal conveyance unit 121 and a development driving unit that drives the photosensitive member 41, the developing roller 131, and the circulation conveyance unit 132, separately. It is done. In this case, the control unit 8 operates the development driving unit in step S3, and stops the development driving unit in step S25. Further, the control unit 8 operates the replenishment drive unit 15 and the intermediate conveyance drive unit in step S16, and stops the replenishment drive unit 15 and the intermediate conveyance drive unit in step S17. Further, the control unit 8 operates the intermediate conveyance driving unit and the development driving unit in step S32, and stops the intermediate conveyance driving unit and the development driving unit in step S34.

  Further, the developing device 43 drives the intermediate conveyance driving unit that drives the intermediate lateral conveyance unit 121, the circulation conveyance driving unit that drives the circulation conveyance unit 132, the photoconductor 41, and the developing roller 131. It is conceivable to provide the development driving unit separately. In this case, the control unit 8 operates the circulation conveyance drive unit and the development drive unit in step S3, and stops the circulation conveyance drive unit and the development drive unit in step S25. Further, the control unit 8 operates the replenishment drive unit 15 and the intermediate conveyance drive unit in step S16, and stops the replenishment drive unit 15 and the intermediate conveyance drive unit in step S17. Further, it is conceivable that the control unit 8 operates the intermediate conveyance driving unit and the circulation conveyance driving unit in step S32 and stops the intermediate conveyance driving unit and the circulation conveyance driving unit in step S34.

  It is also conceivable that the image forming apparatus 10 includes an intermediate transfer belt to which an image on the photoreceptor 41 is transferred, and a belt cleaning device that removes the developer remaining on the intermediate transfer belt. In this case, in the pre-development preprocessing step, the intermediate transfer belt rotates, and the belt cleaning device removes the developer remaining on the intermediate transfer belt.

  The developing device, the image forming apparatus, and the developing device control method according to the present invention can be freely combined or implemented within the scope of the invention described in each claim. It is also possible to configure by modifying the form and application examples as appropriate or omitting some of them.

2: Sheet supply unit 3: Sheet transport unit 4: Image forming unit 5: Optical scanning unit 6: Fixing unit 8: Control unit 9: Recording sheet 10: Image forming apparatus 11: Developer replenishing unit 12: Developer intermediate transport unit 13: Development unit 14: Development drive unit 15: Replenishment drive unit 21: Sheet receiving unit 22: Sheet delivery unit 30: Conveyance path 31: Conveyance roller 41: Photoconductor (image carrier)
42: Charging device 43: Developing device 45: Transfer device 46: Static eliminating device 47: Cleaning device 61: Fixing roller 62: Pressure roller 81: MPU
82: Memory 83: Signal interface 84: Drive circuit 90: Recording sheet 100: Housing 101: Discharge tray 110: Replenishment container 111: Developer delivery unit 120: Horizontal conveyance path 121: Intermediate horizontal conveyance unit 130: Developer tank 131: Developing roller 132: Circulation conveyance unit 610: Heater 800: Developer amount sensor 1101: Developer supply unit outlet 1200: Horizontal conveyance path inlet 1201: Horizontal conveyance path outlet 1300: Development unit inlet Pr1: Development execution control program Pr2: Developer supply control program Pr3: Post-development processing control program Pr4: Pre-development pre-processing control program

Claims (6)

A developer replenishment section for delivering the developer from a replenishment container that contains the developer;
An intermediate horizontal conveyance unit that conveys the developer fed from the developer replenishment unit to an outlet of the horizontal conveyance path along a horizontal conveyance path extending in a lateral direction;
A developing unit having a circulating and conveying unit that circulates the developer in a developing tank that stores the developer sent out from the outlet of the horizontal conveying path, and a developing roller that supplies the developer from the developing tank to the image carrier;
A developer amount sensor for detecting the amount of the developer in the developer tank;
A development execution control unit for executing a development process for developing the electrostatic latent image of the image carrier by operating the circulation conveyance unit and the development roller;
When the development processing is being performed and the detection result of the developer amount sensor satisfies a predetermined shortage condition, the developer replenishment processing is performed by operating the developer replenishment unit and the intermediate lateral conveyance unit. A developer replenishment control unit for executing
A developing device comprising: a development re-processing pre-processing control unit that operates the intermediate lateral conveyance unit and the circulation conveyance unit before the development process and the developer replenishment process are started for the first time after interruption.   The development resumption pre-processing control unit operates the intermediate lateral conveyance unit under an operating condition in which the developer feeding amount is higher when the printing rate in the previous developing process is interrupted than when the printing rate is low. The developing device according to claim 1. The developer replenishment control unit operates the developer replenishment unit and the intermediate lateral conveyance unit for a longer time when the printing rate in the development process is higher than when the printing rate is low,
The development resumption pre-processing control unit is configured to start the first time after the development processing and the developer replenishment processing are interrupted when the printing rate in the previous development processing that was interrupted is higher than when the printing rate is low. The developing device according to claim 2, wherein the intermediate lateral conveyance unit and the circulation conveyance unit are operated for a longer time.   If the developer replenishment process is performed while the development process is being performed, the intermediate lateral conveyance unit and the circulation conveyance unit are continuously operated after the development process is completed and then stopped. The developing device according to claim 1, further comprising a post-development processing control unit. An image carrier;
An image forming apparatus comprising: the developing device according to claim 1. A developer replenishment section for delivering the developer from a replenishment container that contains the developer;
An intermediate horizontal conveyance unit that conveys the developer fed from the developer replenishment unit to an outlet of the horizontal conveyance path along a horizontal conveyance path extending in a lateral direction;
A developing unit having a circulating and conveying unit that circulates the developer in a developing tank that stores the developer sent out from the outlet of the horizontal conveying path, and a developing roller that supplies the developer from the developing tank to the image carrier;
A developer amount sensor for detecting the amount of the developer in the developer tank;
A development execution control step of performing development processing by operating the circulation conveyance unit and the development roller;
When the development processing is being performed and the detection result of the developer amount sensor satisfies a predetermined shortage condition, the developer replenishment processing is performed by operating the developer replenishment unit and the intermediate lateral conveyance unit. A developer replenishment control step for executing
And a development pre-resumption pretreatment control step of operating the intermediate lateral conveyance unit and the circulation conveyance unit before the development process and the developer replenishment process are started for the first time after the interruption.