JP2020201460A - Developing device and image forming apparatus - Google Patents

Abstract

To provide a developing device and an image forming apparatus that can predict in advance the occurrence of retention of developer in the developing device and maintain suitable fluidity of the developer.SOLUTION: A developing device 30 comprises: a developer container 31; a first stirring and conveying member 35 and a second stirring and conveying member 36; a developing roller 37; and a developer amount detection unit 51. In a state where the consumption and supply of developer to the developer container 31 are stopped, the developing device 30 determines the fluidity of the developer in the developer container 31, based on the amount of developer detected by the developer amount detection unit 51 when the conveyance speed of the developer is a developing conveyance speed during a normal developing operation and when the conveyance speed is changed to a determination conveyance speed faster than the developing conveyance speed, when the fluidity is reduced, can execute a developer fluidity recovery mode for rotating the first stirring and conveying member 35 and the second stirring and conveying member 36 in the opposite direction by a predetermined amount, and every time the number of prints reaches a prescribed number of prints, executes the fluidity recovery mode.SELECTED DRAWING: Figure 4

Description

The present invention relates to a developing device and an image forming device including the developing device.

In electrophotographic image forming devices such as copiers and printers, an electrostatic latent image formed on the surface of a photoconductor drum, which is an image carrier, is developed by a developing device to obtain a toner image that is later transferred to paper. The forming device is widely used. In the developing apparatus, in order to realize a stable developing operation, the developing agent is conveyed while stirring in the developing apparatus so that the developing agent maintains a suitable fluidity. Then, a technique for suppressing the retention of the developer even when the fluidity of the developer is reduced has been proposed. An example of such a developing device is disclosed in Patent Document 1.

In the conventional developing apparatus disclosed in Patent Document 1, immediately after the apparatus is stopped or immediately before the start of driving, the stirring and conveying member is rotated by a predetermined angle in the direction opposite to that during normal driving, and the reverse rotation angle is set to the flow of the developer. Change according to gender. As a result, the developer can be dispersed and the retention can be eliminated in the staying portion of the developer in the housing of the developing apparatus. That is, even when the fluidity of the developer decreases, the retention of the developer can be suppressed, and the deterioration of the developer can also be suppressed.

JP-A-2009-36787

However, in the conventional developing apparatus disclosed in Patent Document 1, when the stagnation of the developer occurs in the housing, the stagnation of the developer can be eliminated, but the stagnation of the developer is predicted. The challenge was not being able to do it. Therefore, when the developer stays, there is a concern that image defects due to the decrease in the fluidity of the developer may have already occurred.

The present invention has been made in view of the above points, and is capable of predicting the occurrence of retention of the developer in the developing device and maintaining the suitable fluidity of the developing device and image forming. The purpose is to provide the device.

In order to solve the above problems, the developing apparatus of the present invention includes a developing container, a stirring and transporting member, a developing agent carrier, and a developing agent amount detecting unit. The developing container contains a developing agent to be supplied to the image carrier. The stirring and transporting member transports the developer in the developing container while stirring. The developer carrier supplies the developer in the developing container to the image carrier. The developer amount detection unit detects the amount of the developer in the developing container. In the developing apparatus, with the consumption and replenishment of the developing agent to the developing container stopped, the transport speed of the developer changes to the development transport speed during normal developing operation and the determined transport speed faster than the development transport speed. The fluidity of the developing agent in the developing container is determined based on the amount of the developing agent detected by the developing agent amount detecting unit, and if the fluidity is low, a predetermined amount of the stirring and conveying member is added. It is possible to execute the fluidity recovery mode of the developer which is rotated in the opposite direction, and the fluidity recovery mode is executed every time the number of printed sheets reaches the specified number of printed sheets.

According to the configuration of the present invention, it cannot be grasped when the transport speed of the developer is during normal developing operation, but by changing the transport speed and determining the fluidity of the developer under unusual circumstances, the fluidity of the developer can be determined. It can be predicted that the developer may stay after a while. Therefore, it is possible to predict the occurrence of retention of the developer in the developing apparatus and maintain the suitable fluidity of the developer.

It is schematic cross-sectional view which shows the structure of the image forming apparatus of embodiment of this invention. It is a block diagram which shows the structure of the image forming apparatus of embodiment of this invention. It is sectional drawing which shows the periphery of the image forming part of the image forming apparatus of embodiment of this invention. It is a top view of the developing apparatus of the image forming apparatus of an embodiment of this invention. It is a flowchart which shows the example of the process of the fluidity recovery mode of the developer in the developing apparatus of the image forming apparatus of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

FIG. 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus 1. FIG. 2 is a block diagram showing the configuration of the image forming apparatus 1. FIG. 3 is a cross-sectional view showing the periphery of the image forming portion 20 of the image forming apparatus 1. An example of the image forming apparatus 1 of the present embodiment is a so-called printer that receives image data and commands related to a printing job from an external computer and executes printing.

As shown in FIGS. 1 and 2, the image forming apparatus 1 includes a paper feeding unit 2, a paper conveying unit 3, an exposure unit 4, an image forming unit 20, a developer replenishing device 60, a transfer unit 5, a fixing unit 6, and paper. Includes a discharge unit 7, a control unit 9, and a storage unit 10.

The paper feeding unit 2 accommodates a plurality of sheets of paper P, and separates and sends out the paper P one by one at the time of printing. The paper transport unit 3 transports the paper P fed from the paper feed unit 2 to the transfer unit 5 and the fixing unit 6, and further discharges the fixed paper P from the paper ejection port 3a to the paper ejection unit 7. The exposure unit 4 irradiates the image forming unit 20 with a laser beam controlled based on the image data.

As shown in FIG. 1, the image forming unit 20 includes a photoconductor drum 21 which is an image carrier rotatably supported in a predetermined direction (clockwise in FIG. 1). The image forming unit 20 further includes a charging unit 22, a developing device 30, and a cleaning unit 23 around the photoconductor drum 21 along the rotation direction thereof. The transfer unit 5 is arranged between the developing device 30 and the cleaning unit 23.

The developer replenishing device 60 is arranged above, for example, the developing device 30. The developer replenishing device 60 includes a toner container 61 and a container remaining amount detecting unit 62. The toner container 61 contains a developer to be replenished in the developing container 31. The container remaining amount detecting unit 62 detects the amount of the developer in the toner container 61. The developer replenishing device 60 replenishes the developing agent in the toner container 61 to the developing container 31.

The charging unit 22 charges the surface of the photoconductor drum 21 to a predetermined potential by, for example, corona discharge. Then, an electrostatic latent image of the original image is formed on the surface of the photoconductor drum 21 by the laser light emitted from the exposure unit 4. The developing device 30 supplies toner to the electrostatic latent image and develops it to form a toner image.

The transfer unit 5 transfers the toner image on the surface of the photoconductor drum 21 to the paper P. The cleaning unit 23 removes and cleans the toner remaining on the surface of the photoconductor drum 21 after transfer. The fixing unit 6 heats and pressurizes the paper P on which the toner image is transferred to fix the toner image on the paper P.

The control unit 9 includes a CPU (not shown), an image processing unit, other electronic circuits, and electronic components (not shown). The CPU controls the operation of each component provided in the image forming apparatus 1 based on the control program or data stored in the storage unit 10 to perform processing related to the function of the image forming apparatus 1. Each of the paper feed unit 2, the paper transport unit 3, the exposure unit 4, the image forming unit 20, the developer replenishing device 60, the transfer unit 5, and the fixing unit 6 receives commands individually from the control unit 9, and their components are linked. Then, printing on paper P is executed.

The storage unit 10 is composed of a combination of a non-volatile storage device such as a program ROM (Read Only Memory) and a data ROM (not shown) and a volatile storage device such as a RAM (Random Access Memory).

Subsequently, the configuration of the developing device 30 of the image forming unit 20 will be described with reference to FIG. 4 in addition to FIGS. 1, 2 and 3. FIG. 4 is a plan view of the developing device 30. For convenience of explanation, FIG. 4 omits the drawing of the upper part of the developing container 31 so that the inside of the developing container 31 can be visually recognized from above.

As shown in FIGS. 3 and 4, the developing apparatus 30 includes a developing container 31, a partition 32, a first stirring chamber 33, a second stirring chamber 34, a first stirring and transporting member 35, a second stirring and transporting member 36, and a developing roller. 37, a regulating member 38, and a developer amount detecting unit 51 are provided.

The developing container 31 contains, for example, a magnetic one-component developer composed of only magnetic toner as a developing agent to be supplied to the photoconductor drum 21 which is an image carrier. In the description in this document, the developer may be simply referred to as "toner". The developing container 31 is made of, for example, a molded product of synthetic resin. The developing container 31 has an elongated shape extending in the axial direction, and is arranged with its longitudinal direction horizontal.

The partition portion 32 is provided inside the developing container 31. The partition portion 32 is provided at a substantially central portion in the lateral direction of the developing container 31 (the direction horizontally intersecting the axial direction of the developing roller 37), and extends in the axial direction and the vertical direction. The partition portion 32 divides the inside of the developing container 31 in the lateral direction.

The first stirring chamber 33 and the second stirring chamber 34 are provided inside the developing container 31. The first stirring chamber 33 and the second stirring chamber 34 are formed by dividing the inside of the developing container 31 in the lateral direction by the partition portion 32. That is, the developing container 31 has a first stirring chamber 33 and a second stirring chamber 34 arranged adjacent to the first stirring chamber 33 with the partition portion 32 interposed therebetween.

The first stirring chamber 33 and the second stirring chamber 34 are arranged at substantially the same height in the lateral direction. The second stirring chamber 34 is arranged adjacent to the arrangement region of the developing roller 37 in the developing container 31. The first stirring chamber 33 is arranged in a region of the developing container 31 that is separated from the developing roller 37 by the second stirring chamber 34. The first stirring chamber 33 has the developer supply port 331 shown in FIG. 4, and receives the developer supply from the developer supply device 60 through the developer supply port 331.

The partition portion 32 includes a first communication port 41 and a second communication port 42.

The first communication port 41 is arranged on one end side of the partition portion 32 in the axial direction. The first communication port 41 penetrates the partition portion 32 in the lateral direction, and the developer flows from the first stirring chamber 33 to the second stirring chamber 34.

The second communication port 42 is arranged on the other end side of the partition portion 32 in the axial direction on the opposite side to the one end side where the first communication port 41 is provided. The second communication port 42 penetrates the partition portion 32 in the lateral direction, and the developer flows from the second stirring chamber 34 to the first stirring chamber 33.

The first stirring and transporting member 35 is arranged inside the first stirring chamber 33. The first stirring and transporting member 35 is fixed to a rib portion 35b extending in substantially the entire axial direction of the first stirring chamber 33 between two supporting shaft portions 35a provided at both ends in the axial direction, and is fixed along the axial direction. It is configured to be provided with a screw 35c extending by The first stirring and transporting member 35 is rotatably supported by the developing container 31 around an axis extending in the horizontal direction. The first stirring and transporting member 35 rotates clockwise in FIG. 3, and the developer is in the first direction f1 (see FIG. 4) from the second communication port 42 side to the first communication port 41 side along the rotation axis direction. Is conveyed while stirring.

The second stirring and transporting member 36 is arranged inside the second stirring chamber 34. The second stirring and transporting member 36 is fixed to a rib portion 36b extending over substantially the entire axial direction of the first stirring chamber 33 between two supporting shaft portions 36a provided at both ends in the axial direction, and is fixed along the axial direction. The structure is provided with a screw 36c extending in the direction of the screw 36c. The second stirring and transporting member 36 is rotatably supported by the developing container 31 around an axis extending in the horizontal direction. The second stirring and transporting member 36 rotates clockwise in FIG. 3 and the developer is in the second direction f2 (see FIG. 4) from the first communication port 41 side to the second communication port 42 side along the rotation axis direction. Is conveyed while stirring.

The first direction f1 which is the developer transporting direction of the first stirring and transporting member 35 and the second direction f2 which is the developing agent transporting direction of the second stirring and transporting member 36 are opposite to each other. The developer inside the second stirring chamber 34 is supplied to the developing roller 37.

The developing roller 37 is a developing agent carrier arranged in a region facing the photoconductor drum 21. The developing container 31 is provided with an opening 31a at a position adjacent to the photoconductor drum 21. The developing roller 37 faces the opening 31a and is rotatably supported by the developing container 31 around an axis extending in the horizontal direction. The developing roller 37 rotates counterclockwise in FIG. A part of the peripheral surface of the developing roller 37 is located inside the developing container 31, and the other part of the peripheral surface is exposed to the outside through the opening 31a and faces the photoconductor drum 21. The developing roller 37 supplies the developer inside the second stirring chamber 34 to the photoconductor drum 21 in the region facing the photoconductor drum 21.

For example, the developing roller 37 includes a developing sleeve 371 that is rotatably supported and a magnet 372 that is fixed inside the developing sleeve 371. The developing roller 37 carries a developer on its surface by the magnetic force of the magnet 372. A development bias is applied to the development sleeve 371. The developer (toner) supported on the surface of the developing sleeve 371 is supplied to the photoconductor drum 21 due to the potential difference between the development bias potential and the exposed portion potential on the surface of the photoconductor drum 21. Then, the electrostatic latent image on the surface of the photoconductor drum 21 is developed.

The developing roller 37, the first stirring and transporting member 35, and the second stirring and transporting member 36 are rotatably supported by the developing container 31 about a rotation axis extending in parallel with each other. The developing roller 37, the first stirring and transporting member 35, and the second stirring and transporting member 36 are rotationally driven by a motor (not shown). The first stirring and transporting member 35 and the second stirring and transporting member 36 convey the developer while stirring in the directions opposite to each other in the axial direction. Then, the developing agent circulates between the first stirring chamber 33 and the second stirring chamber 34 through the first communication port 41 and the second communication port 42 of the partition portion 32.

The regulating member 38 is arranged close to the developing roller 37 with a predetermined distance between the tip thereof and the surface of the developing roller 37. The regulating member 38 is the rotation direction of the developing roller 37 in the region facing the developing roller 37 and the second stirring chamber 34 on the downstream side in the rotation direction of the developing roller 37 and in the region facing the developing roller 37 and the photoconductor drum 21. It is located on the upstream side. The regulating member 38 is a regulating member that regulates the layer thickness of the developer on the surface of the developing roller 37.

The developer amount detection unit 51 is arranged in the downstream portion of the first stirring chamber 33 in the first direction f1 which is the developer transporting direction of the first stirring and transporting member 35. The developer amount detecting unit 51 is arranged on the wall portion 33a extending in the vertical direction of the first stirring chamber 33. Further, it is preferable that the developer amount detection unit 51 can detect the amount of the developer up to the height of the upper end of the first stirring and transporting member 35.

The developer amount detection unit 51 is, for example, a magnetic permeability detection type sensor that detects the toner amount (developer amount) by changing the magnetic permeability. The magnetic permeability detection type sensor has, for example, a detection unit composed of a spiral flat coil. If the amount of magnetic toner in the vicinity of the magnetic permeability detection type sensor changes, the magnetic permeability also changes, and the output signal of the detection unit of the magnetic permeability detection type sensor also changes accordingly. For example, as the amount of magnetic toner in the vicinity of the developer amount detection unit 51 increases, the output signal of the developer amount detection unit 51 also increases. As a result, the developer amount detection unit 51 can detect the toner amount (developer amount) in the developing container 31.

Then, the developing apparatus 30 can execute an operation mode called a fluidity recovery mode of the developer housed in the developing container 31. The fluidity recovery mode is executed every time the number of printed sheets reaches the specified number of printed sheets. In the fluidity recovery mode, the fluidity of the developer in the developing container 31 is determined based on the amount of the developer detected by the developer amount detecting unit 51.

In the fluidity recovery mode, when the consumption and replenishment of the developer to the developing container 31 are stopped, the transfer speed of the developer is the development transfer speed during normal development operation, and the determination transfer speed is faster than the development transfer speed. The amount of the developing agent when changed to is detected by the developing agent amount detecting unit 51. The fluidity recovery mode may have two or more determined transport speeds at different speeds. Specifically, for example, it is decided to have a first determination transfer speed which is 1.2 times faster than the development transfer speed and a second determination transfer speed which is 1.5 times faster than the development transfer speed. It's okay.

More specifically, the average value of the output signals of the developer amount detection unit 51 for 10 seconds is acquired at the development transfer speed during normal development operation before the consumption and replenishment of the developer to the developing container 31 are stopped. To do. Subsequently, the transfer speed of the developer is changed to a determination transfer speed faster than the development transfer speed, the developing device 30 is driven for, for example, 60 seconds, and the average value of the output signals of the developer amount detection unit 51 for the last 10 seconds. To get. When the average value of the output signals of the developer amount detection unit 51 at the determination transfer speed becomes larger than the average value of the output signals of the developer amount detection unit 51 at the development transfer speed by a predetermined level or more, the inside of the developing container 31 It is determined that the fluidity of the developer is low.

In the fluidity recovery mode, the fluidity of the developer in the developing container 31 is determined, and when the fluidity is low, the stirring and transporting member is rotated in the reverse direction by a predetermined amount. Specifically, when the fluidity is low, the first stirring and transporting member 35 and the second stirring and transporting member 36 are rotated at a rotation angle of, for example, 180 degrees in the direction opposite to that during normal development operation.

The specified number of prints is preferably derived by adding a correction related to the integrated printing rate and a correction related to the integrated absolute humidity to a predetermined predetermined number of prints. As a result, the specified number of prints takes into consideration the load related to the number of prints, the load related to the printing rate, and the load related to humidity with respect to the developer. For example, the specified number of prints is derived by the following formula (1).

Equation (1) Specified number of prints = number of prints x (3.8 / integrated print rate) x integrated absolute humidity correction value

Here, the "printing rate" means the occupancy rate of toner per predetermined area on the surface of the paper P on which the toner image is transferred and printing is performed, or the number of dots of toner per predetermined area.

The integrated absolute humidity correction value can be obtained from Table 1 below.

The specified number of prints is preferably changed according to the case where the fluidity of the developer is not reduced and the determination transfer speed when the fluidity of the developer is reduced. That is, a plurality of specified print sheets are set. Specifically, for example, the first specified number of prints may be 40,000, the second specified number of prints may be 10,000, and the third specified number of prints may be 1,000.

FIG. 5 is a flowchart showing an example of processing of the fluidity recovery mode of the developer in the developing apparatus 30 of the image forming apparatus 1. The processing of the fluidity recovery mode of the developer in the developing apparatus 30 will be described with reference to the processing flow of FIG.

When the driving of the developing apparatus 30 is started (start of FIG. 5), a normal developing operation is performed while printing up to the first specified number of prints (for example, 40,000 sheets) (step # 101). The developer in the developing container 31 is transported while being stirred at the developing transport speed during normal developing operation.

When the first specified number of prints (for example, 40,000) is reached, the consumption and replenishment of the developer to the developing container 31 is stopped (step # 102). At this time, the average value of the output signals of the developer amount detection unit 51 for 10 seconds is acquired at the development transfer speed during normal development operation before the consumption and replenishment of the developer are stopped.

Subsequently, the transport speed of the developer is changed to a first determination transport speed (for example, 1.2 times faster than the development transport speed), which is faster than the development transport speed, and the developer amount detection unit 51 determines the amount of the developer. Detection is performed (step # 103). Specifically, the transport speed of the developer is changed to the first determination transport speed, the developing device 30 is driven for, for example, 60 seconds, and the average value of the output signals of the developer amount detection unit 51 for the last 10 seconds is acquired. To.

Subsequently, the fluidity of the developer in the developing container 31 is determined based on the amount of the developer detected by the developer amount detecting unit 51 (step # 104). Specifically, when the average value of the output signals of the developer amount detection unit 51 at the first determination transfer speed becomes larger than the average value of the output signals of the developer amount detection unit 51 at the development transfer speed by a predetermined level or more. In addition, it is determined that the fluidity of the developer in the developing container 31 is reduced.

When it is determined that the fluidity of the developer in the developing container 31 has not decreased (No in step # 104), the transfer speed of the developer is determined to be faster than the development transfer speed and the first determination transfer speed. The developing agent amount is detected by the developer amount detecting unit 51 after changing the transfer speed (for example, 1.5 times the developing transfer speed) (step # 105). Specifically, the transport speed of the developer is changed to the second determination transport speed, the developing device 30 is driven for, for example, 60 seconds, and the average value of the output signals of the developer amount detection unit 51 for the last 10 seconds is acquired. To.

Subsequently, the fluidity of the developer in the developing container 31 is determined based on the amount of the developer detected by the developer amount detecting unit 51 (step # 106). Specifically, when the average value of the output signals of the developer amount detection unit 51 at the second determination transfer speed becomes larger than the average value of the output signals of the developer amount detection unit 51 at the development transfer speed by a predetermined level or more. In addition, it is determined that the fluidity of the developer in the developing container 31 is reduced.

When it is determined that the fluidity of the developer in the developing container 31 has not decreased (No in step # 106), the process returns to step # 101 to print up to the next first specified number of prints (for example, 40,000). During that time, normal development operations are performed.

On the other hand, when it is determined that the fluidity of the developer in the developing container 31 is low (Yes in step # 106), the stirring and transporting member is rotated in the reverse direction by a predetermined amount (step # 107). Specifically, the first stirring and transporting member 35 and the second stirring and transporting member 36 are rotated in a direction opposite to that during normal development operation, for example, at a rotation angle of 180 degrees.

Subsequently, a normal development operation is performed while printing up to the next second specified number of prints (for example, 10000 sheets) (step # 108). Then, when the second specified number of prints (for example, 10,000) is reached, the process returns to step # 102, and the consumption and replenishment of the developer to the developing container 31 are stopped. At this time, the average value of the output signals of the developer amount detection unit 51 for 10 seconds is acquired at the development transfer speed during normal development operation before the consumption and replenishment of the developer are stopped.

Subsequently, the transport speed of the developer is changed to a first determination transport speed (for example, 1.2 times faster than the development transport speed), which is faster than the development transport speed, and the developer amount detection unit 51 determines the amount of the developer. Detection is performed (step # 103). Further, the fluidity of the developer in the developing container 31 is determined based on the amount of the developing agent detected by the developing agent amount detecting unit 51 (step # 104).

When it is determined in step # 104 that the fluidity of the developer in the developing container 31 is low (Yes in step # 104), the stirring and transporting member is rotated in the reverse direction by a predetermined amount (step # 109). .. Specifically, the first stirring and transporting member 35 and the second stirring and transporting member 36 are rotated in a direction opposite to that during normal development operation, for example, at a rotation angle of 180 degrees.

Subsequently, a normal development operation is performed while printing up to the next third specified number of prints (for example, 1000 sheets) (step # 110). Then, when the third specified number of prints (for example, 10,000 sheets) is reached, the consumption and replenishment of the developer to the developing container 31 is stopped (step # 111). At this time, the average value of the output signals of the developer amount detection unit 51 for 10 seconds is acquired at the development transfer speed during normal development operation before the consumption and replenishment of the developer are stopped.

Subsequently, the transport speed of the developer is changed to a first determination transport speed (for example, 1.2 times faster than the development transport speed), which is faster than the development transport speed, and the developer amount detection unit 51 determines the amount of the developer. Detection is performed (step # 112). Further, the fluidity of the developer in the developing container 31 is determined based on the amount of the developing agent detected by the developing agent amount detecting unit 51 (step # 113).

When it is determined that the fluidity of the developer in the developing container 31 has not decreased (No in step # 113), the process returns to step # 110 to print up to the next third specified number of prints (for example, 1000 sheets). During that time, normal development operations are performed.

As described above, the developing apparatus 30 executes the fluidity recovery mode of the developer every time the number of printed sheets reaches the specified number of printed sheets. According to this configuration, it is not possible to grasp the transfer speed of the developer during normal development operation, but by changing the transfer speed and determining the fluidity of the developer under unusual circumstances, it will be a while. It can be predicted that the developer may be retained over time. Therefore, it is possible to predict the occurrence of retention of the developer in the developing apparatus 30 and maintain the suitable fluidity of the developer.

Further, as in the above configuration, the fluidity recovery mode may have two or more determination transfer speeds (for example, a first determination transfer speed and a second determination transfer speed) having different speeds. Then, in the fluidity recovery mode, when the fluidity of the developer at the first determination transfer speed is not lowered, the fluidity of the developer is determined at the second determination transfer speed faster than the first determination transfer speed. .. According to this configuration, it is possible to improve the accuracy of predicting the possibility of the developer staying by determining the fluidity of the developer under even more severe conditions.

Further, as in the above configuration, in the fluidity recovery mode, the determination transport speed (for example, the first determination transport speed or the first determination transport speed) when the fluidity of the developer is not reduced and when the fluidity of the developer is reduced 2 Judgment transfer speed), and the specified number of prints (for example, the first specified number of prints, the second specified number of prints, or the third specified number of prints) until the next execution of the fluidity recovery mode is changed. According to this configuration, when the possibility that the developer stays is small, the period until the next fluidity recovery mode is executed is lengthened, and when the possibility that the developer stays is large, then The period until the liquidity recovery mode is implemented can be shortened. Therefore, depending on the state of the developer, the period until the next fluidity recovery mode is executed can be set to an appropriate period.

Further, as in the above configuration, the specified number of prints is derived by adding a correction related to the integrated print rate and a correction related to the integrated absolute humidity to a predetermined predetermined number of prints. When the number of printed sheets is large, the printing rate is low, and the humidity is high, the developer is deteriorated and the fluidity is lowered. Therefore, according to the above configuration, it is possible to carry out the fluidity recovery mode at an appropriate timing based on the usage state of the developing apparatus 30.

Further, as in the above configuration, the developer amount detecting unit 51 is arranged in the downstream portion of the first stirring chamber 33 in the first direction f1. The developer transported in the first direction f1 along the rotation axis direction of the first stirring and transporting member 35 in the first stirring chamber 33 has a transporting direction of the first communication port 41 in the downstream portion of the first direction f1. Since it changes at right angles to the direction, it tends to stay. Therefore, according to the above configuration, the amount of the developing agent can be detected at a place inside the developing container 31 where the developing agent tends to stay. It is known that a large amount of the developer is present at this location as compared with other locations inside the developing container 31, and the amount of the developer can be detected appropriately.

Further, as in the above configuration, the developer amount detection unit 51 is arranged on the wall portion 33a of the first stirring chamber 33, and the developer amount can be detected up to the height of the upper end of the first stirring and transporting member 35. preferable. According to this configuration, the amount of the developer at the location where the developer amount detection unit 51 is arranged can be appropriately detected. Therefore, it is possible to improve the accuracy of determining the fluidity of the developer in the developing container 31 based on the amount of the developing agent detected by the developing agent amount detecting unit 51.

Returning to the processing flow of FIG. 5, when it is determined in step # 113 that the fluidity of the developing agent in the developing container 31 is low (Yes in step # 113), the forced ejection operation of the developing agent is executed. Is done (step # 114). Specifically, the developing apparatus 30 forcibly discharges the developing agent in the developing container 31 onto the surface of the photoconductor drum 21. The developer discharged on the surface of the photoconductor drum 21 is collected by the cleaning unit 23 without being transferred to the paper P.

In this way, the developing apparatus 30 determines the fluidity of the developing agent a plurality of times, and then determines the fluidity of the developing agent at a predetermined predetermined number of prints (for example, a third specified number of prints). When a decrease is observed, the developer in the developing container 31 is forcibly discharged to the photoconductor drum 21. By discharging the deteriorated developer, the developing apparatus 30 can realize high-quality development.

Subsequently, in the image forming apparatus 1, the developer replenishing apparatus 60 detects the amount of the developer in the toner container 61 (step # 115). The amount of the developer in the toner container 61 is detected by the container remaining amount detecting unit 62.

Subsequently, with respect to the amount of the developer in the toner container 61, it is determined whether or not the developer in the toner container 61 can be replenished in the developing container 31 (step # 116). When the developer in the toner container 61 can be replenished to the developing container 31 (Yes in step # 116), it is normal to return to step # 101 and print up to the next first specified number of prints (for example, 40,000 sheets). Development operation is carried out.

When the developing agent cannot be replenished to the developing container 31 (No in step # 116), a notification prompting the replacement of the toner container 61 is performed (step # 117). The notification prompting the replacement of the toner container 61 is, for example, a display on an operation panel (not shown) provided in the housing of the image forming apparatus 1, transmission of notification information to an external computer capable of communicating with the image forming apparatus 1, and the like. Is carried out by. Then, the processing flow shown in FIG. 5 is completed.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the gist of the invention.

For example, in the above embodiment, the developer housed in the developing container 31 is a magnetic one-component developer, but the present invention is not limited to such a configuration. For example, the developer may be a two-component developer containing toner and a magnetic carrier, or it may be a non-magnetic developer.

Further, the developer amount detection unit is not limited to the magnetic permeability detection type sensor, and for example, a piezoelectric sensor, an optical sensor, or the like may be used.

Further, as shown in FIG. 4, the developer amount detecting unit 51 is a wall portion 33a of the first stirring chamber 33 extending along the rotation axis direction of the first stirring and transporting member 35 (the first stirring and transporting member of FIG. 4). Although it was decided to be arranged on the lower wall portion 33a) of the 35, the wall portion 33b extending in the direction intersecting the rotation axis direction of the first stirring and transporting member 35 (on the left side of the first stirring and transporting member 35 in FIG. 4). It may be arranged on the wall portion 33b). Further, the location of the developer amount detection unit 51 is not limited to the downstream portion of the first stirring chamber 33 in the first direction f1 which is the developer transport direction, and is, for example, intermediate between the upstream portion and the downstream portion. It may be.

Further, the numerical values related to the speed, time, angle, humidity, correction value, number of sheets, etc. used in the above description are merely examples, and are not limited to these numerical values, and can be arbitrarily changed as appropriate. ..

Further, in the above embodiment, the image forming apparatus 1 is an image forming apparatus for monochrome printing that forms a monochrome image, but the present invention is not limited to such a model, and an image for color printing is used. It may be a forming device.

The present invention can be used in a developing device and an image forming device including the developing device.

1 Image forming device 9 Control unit 20 Image forming unit 21 Photoreceptor drum (image carrier)
30 Developing device 31 Developing container 33 First stirring chamber 33a, 33b Wall part 34 Second stirring chamber 35 First stirring transport member 36 Second stirring transport member 37 Developing roller (developer carrier)
51 Developer amount detector f1 1st direction f2 2nd direction

Claims (8)

A developing container that houses the developer supplied to the image carrier,
A stirring and transporting member that transports the developer in the developing container while stirring.
A developer carrier that supplies the developer in the developing container to the image carrier, and
A developer amount detection unit that detects the amount of the developer in the developing container, and
In the state where the consumption and replenishment of the developer to the developing container are stopped, the transport speed of the developer is set to the development transport speed during normal development operation and to a determination transport speed faster than the development transport speed. The fluidity of the developer in the developing container is determined based on the amount of the developer detected by the developer amount detection unit when the amount is changed, and if the fluidity is reduced, the fluidity is determined. It is possible to execute the fluidity recovery mode of the developer, which rotates the stirring and conveying member in the opposite direction by a predetermined amount.
A developing apparatus characterized in that the fluidity recovery mode is executed each time the number of printed sheets reaches a specified number of printed sheets. The liquidity recovery mode is
Having two or more of the above-mentioned determined transport speeds at different speeds,
When the fluidity of the developer at a predetermined determination transfer speed is not lowered, the fluidity of the developer is determined at the determination transfer speed faster than the determination transfer speed. The developing apparatus according to claim 1. The liquidity recovery mode is
The specified number of prints until the next execution of the fluidity recovery mode according to the determination transfer speed when the fluidity of the developer is not reduced and when the fluidity of the developer is reduced. The developing apparatus according to claim 2, wherein the developing apparatus is characterized in that. The specified number of prints is claimed from claim 1, wherein the specified number of prints is derived by adding a correction related to the integrated printing rate and a correction related to the integrated absolute humidity to a predetermined predetermined number of prints. Item 3. The developing apparatus according to any one of Items 3. The developing container is arranged adjacent to the first stirring chamber for transporting the developer in the first direction while stirring and the first stirring chamber, and is opposite to the first direction while stirring the developer. It is provided with a second stirring chamber that is conveyed in the second direction and supplied to the developer carrier, and the developer circulates between the first stirring chamber and the second stirring chamber.
The developing apparatus according to any one of claims 1 to 4, wherein the developing agent amount detecting unit is arranged in the downstream portion in the first direction of the first stirring chamber. The first stirring chamber has the stirring and transporting member that transports the developer in the first direction while stirring.
The fifth aspect of claim 5, wherein the developer amount detecting unit is arranged on the wall portion of the first stirring chamber and can detect the developer amount up to the height of the upper end of the stirring and transporting member. Developing equipment. After performing the determination of the fluidity of the developer a plurality of times, when a decrease in the fluidity of the developer is observed in a predetermined predetermined number of prints, the development in the developing container is performed. The developing apparatus according to any one of claims 1 to 6, wherein the agent is forcibly discharged onto the image carrier. An image forming apparatus comprising the developing apparatus according to any one of claims 1 to 7.

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