JP6828615B2 - Deterioration state detection device, image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus and a deterioration state detecting apparatus provided in the image forming apparatus.

The electrophotographic image forming apparatus includes a developing apparatus for developing an electrostatic latent image formed on the surface of a photoconductor drum. This developing device contains a developing agent used for developing an electrostatic latent image. For example, the developer is a two-component developer containing a magnetic carrier and a non-magnetic toner. The developer is triboelectrically charged by stirring by a stirring member provided inside the developing device, and then supplied to the surface of the photoconductor drum.

Further, a so-called trickle developing type developing apparatus is known. In this developing apparatus, the developing agent, that is, both the toner and the carrier, is replenished according to the consumption of the toner in the developing agent. Further, in this developing apparatus, a part of the developing agent increased by replenishment is discharged to the outside of the apparatus. An image forming apparatus including this developing apparatus may include a magnetic permeability sensor capable of detecting the magnetic permeability of the developer in the developing apparatus. In this case, the image forming apparatus controls the supply of the developer to the developer based on the magnetic permeability of the developer detected by the magnetic permeability sensor.

By the way, in the developing apparatus, the developing agent contained therein may be deteriorated by stirring by a stirring member or the like. When the developer deteriorates, the fluidity of the toner and the carrier decreases, and the magnetic permeability of the developer changes regardless of the fluctuation of the toner concentration in the developer. As a result, a deviation may occur between the target value of the toner concentration in the developing unit and the actual toner concentration value in the supply control of the developer using the magnetic permeability sensor. On the other hand, the deteriorated state of the developer is detected by depositing the developer discharged from the developing apparatus on a deposit table and detecting the rest angle formed by the developer deposited on the deposit table. Possible configurations are known as prior art (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-141487

However, in the above-mentioned conventional technique, it is necessary to remove the developer deposited on the deposit table from the deposit table by using a driving unit such as a motor at each detection timing of the deteriorated state of the developer. Therefore, the configuration for detecting the deteriorated state of the developer becomes complicated.

An object of the present invention is to provide a deterioration state detection device and an image forming device capable of detecting a deterioration state of a developer with a simple configuration.

The deterioration state detection device according to one aspect of the present invention includes a swing unit, a center of gravity displacement unit, a detection unit, and an output unit. The swinging portion has a first receiving surface for receiving the developing agent discharged and dropped from the developing unit for developing an electrostatic latent image using a developing agent, and the first receiving surface is centered on a horizontal axis. It is swingably supported between a first position where the developer can be deposited on the surface and a second position where the developer can be slid off from the first receiving surface. When the rotational torque around the horizontal axis applied by the developer deposited on the first receiving surface exceeds a predetermined first threshold value, it rotates from the first position to the second position. The center-of-gravity displacement portion is provided on the swinging portion, and the center of gravity of the powder of the developing agent deposited on the first receiving surface in response to an increase in the amount of the developing agent deposited on the first receiving surface. Displace in the first direction away from the horizontal axis. The detection unit detects that the amount of deposit exceeds a predetermined second threshold value. When the detection unit detects that the deposited amount exceeds the second threshold value, the output unit outputs a detection signal indicating a deterioration state of the developer corresponding to the second threshold value.

The image forming apparatus according to another aspect of the present invention includes the deterioration state detecting apparatus and the developing unit.

According to the present invention, it is possible to detect the deteriorated state of the developer with a simple structure.

FIG. 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a system configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a configuration of an image forming unit of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a diagram showing a configuration of a developing unit of the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram showing a configuration of a deterioration state detection unit of the image forming apparatus according to the embodiment of the present invention. FIG. 6 is a diagram showing a configuration of a deposit portion of the image forming apparatus according to the embodiment of the present invention. FIG. 7 is a diagram showing a configuration of a swinging portion of the image forming apparatus according to the embodiment of the present invention. FIG. 8 is a diagram showing a configuration of a swinging portion of the image forming apparatus according to the embodiment of the present invention. FIG. 9 is a diagram showing a configuration of a swinging portion of the image forming apparatus according to the embodiment of the present invention. FIG. 10 is a flowchart showing an example of supply control processing executed by the image forming apparatus according to the embodiment of the present invention. FIG. 11 is a diagram showing a configuration of a swinging portion and a detecting portion of the image forming apparatus according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for the purpose of understanding the present invention. The following embodiments are examples that embody the present invention, and do not limit the technical scope of the present invention.

[Rough configuration of image forming apparatus 10]
First, the configuration of the image forming apparatus 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus 10.

For convenience of explanation, the vertical direction is defined as the vertical direction D1 in the installed state (state shown in FIG. 1) in which the image forming apparatus 10 can be used. Further, the front-rear direction D2 is defined with the left side surface of the image forming apparatus 10 shown in FIG. 1 as the front surface (front surface). Further, the left-right direction D3 is defined with reference to the front surface of the image forming apparatus 10 in the installed state.

The image forming apparatus 10 is a multifunction device having a plurality of functions such as a scanning function, a facsimile function, and a copying function, as well as a printing function for forming an image based on image data. The present invention can be applied to image forming devices such as printer devices, facsimile machines, and copiers.

Specifically, as shown in FIGS. 1 and 2, the image forming apparatus 10 includes an ADF (automatic document transporting apparatus) 1, an image reading unit 2, an image forming unit 3, a paper feeding unit 4, a control unit 5, and an operation. It includes a display unit 6 and a deterioration state detection unit 7.

The ADF 1 is an automatic document transporting device that includes a document setting section (not shown), a plurality of transport rollers, a document retainer, and a paper ejection section, and transports documents read by the image reading unit 2. The image reading unit 2 includes a document stand (not shown), a light source, a plurality of mirrors, an optical lens, and a CCD, and can read image data from the document.

The paper feed unit 4 includes a paper feed cassette, a sheet transport path, a plurality of transport rollers, and the like. The paper feed unit 4 supplies the sheet housed in the paper feed cassette to the image forming unit 3. For example, the sheets housed in the paper cassette are sheet materials such as paper, coated paper, postcards, envelopes, and transparencies.

The control unit 5 includes control devices such as a CPU, ROM, RAM, and EEPROM (registered trademark) (not shown). The CPU is a processor that executes various arithmetic processes. The ROM is a non-volatile storage device in which information such as a control program for causing the CPU to execute various processes is stored in advance. The RAM is a volatile storage device, and the EEPROM is a non-volatile storage device. The RAM and EEPROM are used as temporary storage memories (working areas) for various processes executed by the CPU. In the control unit 5, various control programs stored in advance in the ROM are executed by the CPU. As a result, the image forming apparatus 10 is collectively controlled by the control unit 5. The control unit 5 may be composed of an electronic circuit such as an integrated circuit (ASIC), and is a control unit provided separately from the main control unit that collectively controls the image forming apparatus 10. You may.

The operation display unit 6 includes a display unit such as a liquid crystal display that displays various information in response to a control instruction from the control unit 5, an operation key or a touch panel that inputs various information to the control unit 5 in response to a user operation. It has an operation unit of.

[Structure of image forming unit 3]
Next, the configuration of the image forming unit 3 will be described with reference to FIGS. 1 to 5. Here, FIG. 3 is a schematic cross-sectional view showing the configuration of the image forming unit 31. Further, FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. Further, FIG. 5 is a sectional view taken along line VV in FIG. The alternate long and short dash line in FIG. 4 is for indicating the position of the carry-in inlet 313M in the developing unit 313. The dotted line in FIG. 5 is for indicating the developing agent G. Further, the broken line in FIG. 5 is for indicating the light L1 emitted from the light emitting unit 73A.

The image forming unit 3 can execute an image forming process (printing process) for forming a color or monochrome image by an electrophotographic method based on the image data read by the image reading unit 2. Further, the image forming unit 3 can also execute the printing process based on the image data input from an information processing device such as an external personal computer.

As shown in FIG. 1, the image forming unit 3 includes a plurality of image forming units 31 to 34, an optical scanning device 35, an intermediate transfer belt 36, a secondary transfer roller 37, a fixing device 38, and a paper ejection tray 39. ..

The image forming unit 31 is Y (yellow), the image forming unit 32 is C (cyan), the image forming unit 33 is M (magenta), and the image forming unit 34 is K (black). is there. As shown in FIG. 1, the image forming units 31 to 34 are arranged in the order of yellow, cyan, magenta, and black from the front of the image forming apparatus 10 along the front-rear direction D2 of the image forming apparatus 10.

As shown in FIGS. 1 and 3, the image forming unit 31 includes a photoconductor drum 311, a charging unit 312, a developing unit 313, a primary transfer roller 314, a drum cleaning unit 315, and a developing agent supply unit 316. Further, each of the image forming units 32 to 34 has the same configuration as the image forming unit 31.

An electrostatic latent image is formed on the surface of the photoconductor drum 311. The photoconductor drum 311 rotates in the rotation direction D4 shown in FIG. 3 by a driving force supplied from a power source (not shown).

The charging unit 312 charges the photoconductor drum 311. For example, the charging unit 312 is a roller member provided in contact with the photoconductor drum 311 as shown in FIG.

The developing unit 313 develops an electrostatic latent image formed on the photoconductor drum 311 using a developing agent G (see FIG. 5) containing a magnetic carrier and a non-magnetic toner. The developing unit 313 will be described in detail later.

The primary transfer roller 314 transfers the toner image formed on the surface of the photoconductor drum 311 by the developing unit 313 to the intermediate transfer belt 36.

The drum cleaning unit 315 removes the toner remaining on the surface of the photoconductor drum 311.

The developer supply unit 316 supplies the developer G to the developing unit 313.

The optical scanning device 35 forms an electrostatic latent image on the surface of each of the photoconductor drums of the image forming units 31 to 34.

The intermediate transfer belt 36 is an endless belt member on which a toner image formed on the surface of each of the photoconductor drums of the image forming units 31 to 34 is transferred. The intermediate transfer belt 36 is stretched with a predetermined tension by a drive roller and a tension roller. The intermediate transfer belt 36 moves along the front-rear direction D2 of the image forming apparatus 10 by rotationally driving the drive roller by a driving force supplied from a power source (not shown).

The secondary transfer roller 37 transfers the toner image adhering to the surface of the intermediate transfer belt 36 to the sheet.

The fixing device 38 melts and fixes the toner image transferred to the sheet by the secondary transfer roller 37 to the sheet.

The sheet on which the toner image is fixed by the fixing device 38 is discharged to the paper ejection tray 39.

In the image forming unit 3, a color image is formed on the sheet supplied from the paper feeding unit 4 by the following procedure, and the sheet after the image formation is discharged to the paper ejection tray 39.

First, in the image forming unit 31, the photoconductor drum 311 is uniformly charged to a predetermined potential by the charging unit 312. Next, the light scanning device 35 irradiates the surface of the photoconductor drum 311 with light based on the image data. As a result, an electrostatic latent image corresponding to the image data is formed on the surface of the photoconductor drum 311. Then, the electrostatic latent image on the photoconductor drum 311 is developed (visualized) as a yellow toner image by the developing unit 313.

Subsequently, the yellow toner image formed on the photoconductor drum 311 is transferred to the intermediate transfer belt 36 by the primary transfer roller 314. On the other hand, the toner remaining on the surface of the photoconductor drum 311 is removed by the drum cleaning unit 315. For example, in the drum cleaning unit 315, the toner remaining on the surface of the photoconductor drum 311 is removed by a blade-shaped cleaning member. Then, the toner removed by the cleaning member is transported to a toner container (not shown) by a screw-shaped transport member and recovered.

In the image forming units 32 to 34, toner images of each color are formed on the photoconductor drums of the image forming units 32 to 34 by the same processing procedure as in the image forming unit 31, and the intermediate transfer belt 36 is yellowed. The images are transferred in the order of cyan, magenta, and black. Then, the toner image transferred to the intermediate transfer belt 36 is transferred to the sheet supplied from the paper feed unit 4 by the secondary transfer roller 37. After that, the sheet on which the toner image is transferred is formed by melting and fixing the toner image by the fixing device 38, and is discharged to the paper ejection tray 39.

Next, the developing unit 313 will be described in detail.

As shown in FIGS. 3 and 4, the developing unit 313 includes a housing 313A, a first conveying member 313B, a second conveying member 313C, a magnet roller 313D, a developing roller 313E, and a magnetic permeability sensor 313N.

The housing 313A is formed in a long rectangular parallelepiped shape in the left-right direction D3. As shown in FIG. 3, the housing 313A houses the first transport member 313B, the second transport member 313C, the magnet roller 313D, and the developing roller 313E. Further, the housing 313A accommodates the developer G.

As shown in FIG. 4, the housing 313A has a first transport path 313H and a second transport path 313J. Specifically, the bottom portion 313F of the housing 313A is provided with a partition wall 313G extending in the left-right direction D3 as shown in FIGS. 3 and 4. The side wall, the bottom portion 313F, and the partition wall 313G of the housing 313A form a long first transport path 313H and a second transport path 313J in the left-right direction D3.

The first transport member 313B is provided in the first transport path 313H as shown in FIG. For example, the first transport member 313B is a screw-shaped member that is long in the left-right direction D3 and has a rotation axis extending in the left-right direction D3. The rotation shaft of the first transport member 313B is rotatably supported by the housing 313A. The first transport member 313B is rotationally driven by the driving force supplied from the power source to transport the developer G in the right direction D31 (see FIG. 4), and the carrier and the carrier contained in the developer G. The toner is triboelectrically charged.

The second transport member 313C is provided in the second transport path 313J as shown in FIG. For example, the second transport member 313C, like the first transport member 313B, is a screw-shaped member that is long in the left-right direction D3 and has a rotation axis extending in the left-right direction D3. The rotation shaft of the second transport member 313C is rotatably supported by the housing 313A. The second transport member 313C is rotationally driven by the driving force supplied from the power source to transport the developer G in the left direction D32 (see FIG. 4), and the carrier and the carrier included in the developer G. The toner is triboelectrically charged.

At the downstream end of the partition wall 313G in the transport direction (right direction D31) of the developer G by the first transport member 313B, a first connection portion 313K connecting the first transport path 313H and the second transport path 313J (see FIG. 4). ) Is provided. On the other hand, at the downstream end of the partition wall 313G in the transport direction (left direction D32) of the developer G by the second transport member 313C, the second connecting portion 313L connecting the first transport path 313H and the second transport path 313J (FIG. 4) is provided. As a result, the developer G housed in the housing 313A is circulated and transported by the first transport member 313B and the second transport member 313C through the first transport path 313H and the second transport path 313J.

The magnet roller 313D pumps up the developer G from the second transport path 313J, and supplies the toner contained in the pumped developer G to the developing roller 313E. The developing roller 313E develops an electrostatic latent image formed on the surface of the photoconductor drum 311 by using the toner supplied from the magnet roller 313D.

The developing method by the developing unit 313 is not limited to the two-component developing method using the toner and the developing agent G containing the carrier described above. For example, the developing method of the developing unit 313 may be a one-component developing method using a magnetic toner. Further, the developing unit 313 may not be provided with the magnet roller 313D.

Here, the image forming apparatus 10 employs a so-called trickle developing method. Specifically, in the image forming apparatus 10, the developing agent G, that is, both the toner and the carrier is replenished from the developing agent supply unit 316 according to the consumption of the toner in the developing unit 313. Further, in the developing unit 313, a part of the developing agent G increased by replenishment is discharged to the outside of the housing 313A.

As shown in FIG. 3, a carry-in inlet 313M is formed in the housing 313A. Specifically, the carry-in inlet 313M is formed above the predetermined carry-in position P1 (see FIG. 4) in the first transport path 313H. For example, the carry-in position P1 is a position on the upstream side in the transport direction (right direction D31) of the developer G by the first transport member 313B in the first transport path 313H. The carry-in port 313M is used for carrying the developer G supplied from the developer supply unit 316 into the first transport path 313H.

The magnetic permeability sensor 313N detects the magnetic permeability of the developer G housed in the housing 313A. Specifically, the magnetic permeability sensor 313N is located at a detection position P2 (see FIG. 4) downstream of the carry-in position P1 in the first transport path 313H in the transport direction (right direction D31) of the developer G by the first transport member 313B. The magnetic permeability of the developer G is detected. As shown in FIG. 3, the magnetic permeability sensor 313N is provided on the outer surface side of the bottom 313F. The magnetic permeability sensor 313N outputs a first electric signal indicating the magnetic permeability of the developer G. In the image forming apparatus 10, the supply of the developer G from the developer supply unit 316 to the developing unit 313 is controlled based on the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N.

As shown in FIG. 4, an opening 313O is formed at the downstream end in the second transport path 313J in the transport direction (left direction D32) of the developer G by the second transport member 313C. As shown in FIG. 5, the opening 313O is formed on the inner surface of the housing 313A at a position higher than the bottom 313F. The opening 313O is connected to a discharge port 313Q (see FIG. 5) formed in the bottom 313F via a discharge path 313P (see FIG. 5) provided in the housing 313A.

In the image forming apparatus 10, when the developer G is supplied from the developer supply unit 316 to the developing unit 313, the upper surface of the powder of the developer G in the second transport path 313J rises. Then, when the upper surface of the powder exceeds the lower end of the opening 313O, a part of the powder moves from the opening 313O to the discharge path 313P, falls from the discharge port 313Q, and is discharged to the outside of the developing unit 313. Will be done.

By the way, in the developing unit 313, the developing agent G contained therein may be deteriorated by stirring by the first conveying member 313B and the second conveying member 313C. When the developer G deteriorates, the fluidity of the toner and the carrier decreases, and the magnetic permeability of the developer G changes regardless of the fluctuation of the toner concentration in the developer G. Specifically, when the developer G deteriorates, the magnetic permeability of the developer G decreases. As a result, there may be a discrepancy between the target value of the toner concentration in the developing unit 313 and the actual toner concentration value in the supply control of the developer G using the magnetic permeability sensor 313N. On the other hand, the developer G discharged from the developing unit 313 is deposited on a deposit table, and the rest angle formed by the developer G deposited on the deposit table is detected to detect the deteriorated state of the developer G. A detectable configuration is known as a prior art.

However, in the above-mentioned conventional technique, it is necessary to remove the developer G deposited on the deposit table from the deposit table by using a driving unit such as a motor at each detection timing of the deteriorated state of the developer G. Therefore, the configuration for detecting the deteriorated state of the developer G becomes complicated.

On the other hand, in the image forming apparatus 10 according to the embodiment of the present invention, it is possible to detect the deteriorated state of the developer G with a simple configuration as described below.

[Structure of deterioration state detection unit 7]
Hereinafter, the configuration of the deterioration state detection unit 7 will be described with reference to FIGS. 2 and 5 to 9. Here, FIG. 6 is a perspective view showing the configuration of the sedimentary portion 721. Further, FIG. 7 is a diagram showing a state in which the swing portion 72 is arranged at the first position P3. Further, FIG. 8 is a diagram showing a state in which the swing portion 72 is arranged at the second position P4. Further, FIG. 9 is a diagram showing a state in which the deteriorated developer G is deposited on the first receiving surface 721A1. The dotted lines in FIGS. 7 to 9 are for indicating the developing agent G. Further, the broken lines in FIGS. 7 to 9 are for indicating the light L1 emitted from the light emitting unit 73A. The two-dot chain line in FIGS. 7 and 8 is for indicating the inclination angles C1 and C2 of the partition wall portion 721D with respect to the vertical plane.

The deterioration state detection unit 7 detects the deterioration state of the developer G discharged from the developing unit 313. As shown in FIGS. 2 and 5, the deterioration state detection unit 7 includes a housing 71, a swing unit 72, a detection unit 73, and an output unit 74. Here, the deterioration state detection unit 7 is an example of the deterioration state detection device in the present invention.

The housing 71 accommodates the swing unit 72, the detection unit 73, and the output unit 74. For example, the housing 71 is formed in a rectangular parallelepiped box shape and has an internal space 71A. The swing unit 72, the detection unit 73, and the output unit 74 are housed in the internal space 71A.

As shown in FIG. 5, the housing 71 has an opening 71B and a discharge port 71C. The opening 71B is formed on the upper surface of the housing 71. The opening 71B connects the outside of the housing 71 and the internal space 71A. The discharge port 71C is formed on the lower surface of the housing 71. The discharge port 71C connects the outside of the housing 71 to the internal space 71A.

As shown in FIG. 5, the housing 71 is provided below the housing 313A of the developing unit 313. Specifically, the housing 71 is fixed to the bottom 313F of the developing unit 313 at a position where the opening 71B faces the discharge port 313Q of the developing unit 313. As a result, the developer G that has fallen from the discharge port 313Q falls into the internal space 71A via the opening 71B. The discharge port 71C of the housing 71 is connected to a developer container (not shown) via a transport path (not shown).

The rocking portion 72 is rocked by the developing agent G that falls from the opening 71B. As shown in FIG. 5, the swing portion 72 has a deposit portion 721, a connection portion 722, and a rotation shaft 723.

The deposition portion 721 has a bottom plate portion 721A, side wall portions 721B to 721C, and a partition wall portion 721D, as shown in FIGS. 5 and 6. The bottom plate portion 721A is formed in a rectangular flat plate shape. The side wall portions 721B to 721C are erected at each end portion of the bottom plate portion 721A in the lateral direction of the bottom plate portion 721A. As shown in FIG. 6, the side wall portion 721B is formed in a shape in which the wall of the bottom plate portion 721A gradually becomes lower from the central portion in the longitudinal direction of the bottom plate portion 721A toward each of the end portions in the longitudinal direction. For example, the side wall portion 721B is formed in a flat plate shape of an isosceles triangle. The side wall portion 721C is formed in the same shape as the side wall portion 721B. The partition wall portion 721D divides the surfaces (surfaces) of the bottom plate portion 721A on the side where the side wall portions 721B to 721C are erected into the first receiving surface 721A1 and the second receiving surface 721A2 shown in FIG. For example, the partition wall portion 721D is erected at the central portion of the bottom plate portion 721A in the longitudinal direction of the bottom plate portion 721A. The partition wall portion 721D is formed in a flat plate shape perpendicular to the first receiving surface 721A1 and the second receiving surface 721A2. The first receiving surface 721A1 and the second receiving surface 721A2 receive the developer G discharged from the developing unit 313 and dropped. The deposit portion 721 is formed in a shape symmetrical with respect to the plane including the partition wall portion 721D.

As shown in FIG. 5, the connecting portion 722 is provided on the back surface of the bottom plate portion 721A of the depositing portion 721. The connecting portion 722 connects the depositing portion 721 and the rotating shaft 723. Specifically, the connecting portion 722 connects the depositing portion 721 and the rotating shaft 723 in a positional relationship in which the rotating shaft 723 is included in the plane including the partition wall portion 721D.

The rotation shaft 723 is a shaft extending along the horizontal plane. Specifically, the rotation shaft 723 extends along the front-rear direction D2 as shown in FIG. The rotation shaft 723 is arranged below the opening 71B and is rotatably supported by the housing 71. As a result, the swing portion 72 is rotatably supported by the housing 71 in the rotation direction D5 shown in FIG. 5 around the rotation shaft 723. Specifically, the swinging portion 72 swings between the first position P3 shown in FIGS. 5 and 7 and the second position P4 shown in FIG. Here, the rotation shaft 723 is an example of the horizontal shaft in the present invention.

Here, the first position P3 is a position where the developer G falling from the opening 71B can be deposited on the first receiving surface 721A1 of the deposition portion 721. Specifically, the first position P3 is a position where the drop path of the developer G from the opening 71B and the first receiving surface 721A1 intersect. Further, the first position P3 is a position where the developer G deposited on the second receiving surface 721A2 can be slid down from the second receiving surface 721A2. Specifically, in the first position P3, the second receiving surface 721A2 is downward from the end portion on the partition wall portion 721D side in the direction orthogonal to the partition wall portion 721D on the second receiving surface 721A2 toward the other end portion. This is the position where the posture is tilted.

For example, the first position P3 is a position where the inclination angle of the partition wall portion 721D with respect to the vertical plane including the rotation shaft 723 is the inclination angle C1 shown in FIG. For example, as shown in FIG. 7, the housing 71 comes into contact with the bottom plate portion 721A of the depositing portion 721 and locks the rotation of the swinging portion 72 in the rotation direction D51 (see FIG. 7). 1 It has a locking portion 71D. The first position P3 is a position where the swinging portion 72 comes into contact with the first locking portion 71D.

Further, the second position P4 is a position where the developer G falling from the opening 71B can be deposited on the second receiving surface 721A2 of the deposition portion 721. Specifically, the second position P4 is a position where the drop path of the developer G from the opening 71B and the second receiving surface 721A2 intersect. Further, the second position P4 is a position where the developer G deposited on the first receiving surface 721A1 can be slid down from the first receiving surface 721A1. Specifically, in the second position P4, the first receiving surface 721A1 is downward from the end portion on the partition wall portion 721D side in the direction orthogonal to the partition wall portion 721D on the first receiving surface 721A1 toward the other end portion. This is the position where the posture is tilted.

For example, the second position P4 is a position where the inclination angle of the partition wall portion 721D with respect to the vertical plane including the rotation shaft 723 is the inclination angle C2 shown in FIG. For example, the tilt angle C2 has a sign opposite to that of the tilt angle C1 and has the same absolute value as the tilt angle C1. For example, as shown in FIG. 8, the housing 71 comes into contact with the bottom plate portion 721A of the depositing portion 721 and locks the rotation of the swinging portion 72 in the rotation direction D52 (see FIG. 8). It has 2 locking portions 71E. The second position P4 is a position where the swinging portion 72 comes into contact with the second locking portion 71E.

For example, the rocking portion 72 is arranged at either the first position P3 or the second position P4 in a state where the developer G is not deposited on both the first receiving surface 721A1 and the second receiving surface 721A2. To. Here, it is assumed that the device is located at the first position P3. In this state, the swinging portion 72 is locked by the first locking portion 71D in the rotation direction D51 due to its own weight. In this case, a rotation torque F1 (see FIG. 7) for rotating the swing portion 72 in the rotation direction D51 is applied to the rotation shaft 723 due to the weight of the swing portion 72.

When the developer G is discharged from the developing unit 313 with the rocking portion 72 arranged at the first position P3, the developing agent G falling from the opening 71B is received by the first receiving surface 721A1. It is deposited on the first receiving surface 721A1. The developer G deposited on the first receiving surface 721A1 forms a conical powder. When the amount of the developer G deposited on the first receiving surface 721A1 increases, the rocking portion 72 added by the developer G deposited on the first receiving surface 721A1 is rotated in the rotation direction D52. The rotational torque F2 (see FIG. 7) is gradually increased. Then, when the rotational torque F2 exceeds the rotational torque F1, the rocking portion 72 rotates from the first position P3 to the second position P4, and the developer G deposited on the first receiving surface 721A1 is the first. 1 It slides down from the receiving surface 721A1. As a result, the swinging portion 72 is arranged at the second position P4. The developer G that has slipped off the first receiving surface 721A1 is discharged from the discharge port 71C to the outside of the deterioration state detection unit 7. Here, the rotational torque F1 due to the weight of the swinging portion 72 is an example of the first threshold value in the present invention.

Here, the developer G deposited on the first receiving surface 721A1 is separated from the rotation shaft 723 by the partition wall portion 721D in the second direction D7 (see FIG. 7) in the direction opposite to the first direction D6 (see FIG. 7). See) is prevented from moving to. As a result, the powder of the developer G formed on the first receiving surface 721A1 increases in the first direction D6 as the amount of the developing agent G deposited on the first receiving surface 721A1 increases. Therefore, the center of gravity X of the powder is displaced in the first direction D6. That is, the partition wall portion 721D shifts the center of gravity X of the powder of the developer G deposited on the first receiving surface 721A1 to the first direction D6 in accordance with the increase in the amount of the developing agent G deposited on the first receiving surface 721A1. Displace. Here, the partition wall portion 721D is an example of the center of gravity displacement portion in the present invention and also an example of the barrier in the present invention.

Further, when the developer G deposited on the first receiving surface 721A1 is deteriorated, the friction coefficient on the surface of the carrier becomes large, and the powder of the developing agent G formed on the first receiving surface 721A1 becomes large. The fluidity of the developer G on the surface of the body is reduced. As a result, the angle of repose of the powder of the developer G formed on the first receiving surface 721A1 is increased. That is, the rate of increase of the powder in the first direction D6 becomes slow. Therefore, the speed at which the center of gravity X of the powder of the developer G deposited on the first receiving surface 721A1 by the partition wall portion 721D is displaced in the first direction D6 becomes slow. Therefore, the amount of the developer G deposited in order to obtain the rotational torque F2 exceeding the rotational torque F1 increases. That is, in the deterioration state detection unit 7, as the developer G deteriorates, the upper limit of the amount of the developer G that can be deposited on the first receiving surface 721A1 increases.

On the other hand, in the state where the swinging portion 72 is arranged at the second position P4, the swinging portion 72 is locked by the second locking portion 71E in the rotation direction D52 due to its own weight. In this case, a rotation torque F3 (see FIG. 8) for rotating the swing portion 72 in the rotation direction D52 is applied to the rotation shaft 723 due to the weight of the swing portion 72.

When the developer G is discharged from the developing unit 313 with the rocking portion 72 arranged at the second position P4, the developing agent G falling from the opening 71B is closer to the second direction D7 than the partition wall portion 721D. It is received by the second receiving surface 721A2 located and is deposited on the second receiving surface 721A2. When the amount of the developer G deposited on the second receiving surface 721A2 increases, the rocking portion 72 added by the developer G deposited on the second receiving surface 721A2 is rotated in the rotation direction D51. The rotational torque F4 (see FIG. 8) is gradually increased. Then, when the rotational torque F4 exceeds the rotational torque F3, the rocking portion 72 rotates from the second position P4 to the first position P3, and the developer G deposited on the second receiving surface 721A2 becomes the second. 2 It slides down from the receiving surface 721A2. As a result, the swinging portion 72 is arranged at the first position P3. The developer G that has slipped off the second receiving surface 721A2 is discharged from the discharge port 71C to the outside of the deterioration state detection unit 7. Here, the rotational torque F3 due to the weight of the swinging portion 72 is an example of the third threshold value in the present invention.

Here, the developer G deposited on the second receiving surface 721A2 is prevented from moving in the first direction D6 (see FIG. 8) by the partition wall portion 721D. As a result, the powder of the developer G formed on the second receiving surface 721A2 is in the second direction D7 (see FIG. 8) in accordance with the increase in the amount of the developing agent G deposited on the second receiving surface 721A2. ). Therefore, the center of gravity X of the powder is displaced in the second direction D7.

Further, when the developer G deposited on the second receiving surface 721A2 is deteriorated, the powder of the developing agent G formed on the second receiving surface 721A2 is similarly to the first receiving surface 721A1. The rate of increase in the second direction D7 is slowed down. Therefore, the speed at which the center of gravity X of the powder of the developer G deposited on the second receiving surface 721A2 by the partition wall portion 721D is displaced in the second direction D7 becomes slow. Therefore, the amount of the developer G deposited in order to obtain the rotational torque F4 exceeding the rotational torque F3 increases. That is, in the deterioration state detection unit 7, the more the developer G deteriorates, the larger the upper limit amount of the developer G that can be deposited on the second receiving surface 721A2.

Here, in the image forming apparatus 10, the rotational torque F1 and the rotational torque F3 are set to the same value. For example, the swing portion 72 is formed in a shape that includes a rotation shaft 723 and is plane-symmetric with respect to a plane orthogonal to the bottom plate portion 721A. Thereby, it is possible to detect the deteriorated state of the developer G on both the first receiving surface 721A1 and the second receiving surface 721A2.

In the image forming apparatus 10, the rotational torque F1 and the rotational torque F3 may be set to different values. For example, the swing portion 72 may not be formed in a shape that includes the rotation shaft 723 and is plane-symmetric with respect to a plane orthogonal to the bottom plate portion 721A. For example, the partition wall portion 721D may be provided on the second direction D7 (see FIG. 7) side of the plane including the rotation shaft 723 and orthogonal to the bottom plate portion 721A. In this case, the second receiving surface 721A2 may be provided with a weight for increasing the rotational torque F1. Further, the rotation shaft 723 may be arranged on the left side of the lower side of the opening 71B. Further, the swing portion 72 may not be provided with the second receiving surface 721A2. For example, the swing portion 72 may be urged in the rotation direction D51 by an urging member such as a torsion coil spring.

The detection unit 73 detects that the amount of the developer G deposited on the rocking unit 72 exceeds a predetermined second threshold value.

For example, the detection unit 73 is an optical sensor that detects the powder of the developer G deposited on the rocking unit 72 at a predetermined detection position P5 (see FIGS. 7 to 9) above the rocking unit 72. is there.

As described above, in the rocking portion 72, as the developing agent G deteriorates, the upper limit amount of the developing agent G that can be deposited on the first receiving surface 721A1 and the second receiving surface 721A2 increases, and the developing is performed. The angle of repose of agent G increases. Therefore, in the rocking portion 72, the height of the top of the powder of the developer G deposited on the first receiving surface 721A1 or the second receiving surface 721A2 when the rocking portion 72 rotates is the height of the developer G. It reflects the deterioration state of the above and the amount of the developer G deposited on the rocking portion 72. That is, based on whether or not the height of the top of the powder of the developer G deposited on the rocking portion 72 has reached a predetermined position, the amount of the developer G deposited on the rocking portion 72 is the position. It is possible to detect that the amount corresponding to is exceeded.

For example, the detection position P5 is the position (high) of the top of the powder of the developer G when the developer G with the accumulated amount of the second threshold value is deposited on the first receiving surface 721A1 or the second receiving surface 721A2. It is). The detection position P5 is a portion other than the top of the powder of the developer G when the developer G with the accumulated amount of the second threshold value is deposited on the first receiving surface 721A1 or the second receiving surface 721A2. It may be a position (height). Further, the second threshold value may be an arbitrarily determined value.

Specifically, the detection unit 73 includes a light emitting unit 73A and a light receiving unit 73B, as shown in FIGS. 7 to 9. The light emitting unit 73A and the light receiving unit 73B are provided so as to face each other with the detection position P5 interposed therebetween. The light emitting unit 73A emits light L1 toward the light receiving unit 73B. The light receiving unit 73B outputs a second electric signal according to the presence or absence of light reception of the light L1 emitted from the light emitting unit 73A. As a result, the detection unit 73 outputs the second electric signal according to the presence or absence of powder of the developer G at the detection position P5.

The deterioration state detection unit 7 may include a plurality of detection units 73 having different positions (heights) at which the powder of the developer G can be detected. In this case, the second threshold value is set for each individual detection unit 73.

When the detection unit 73 detects that the accumulated amount of the developer G in the rocking unit 72 exceeds the second threshold value, the output unit 74 determines the deterioration state of the developer G corresponding to the second threshold value. The indicated detection signal is output.

Specifically, the output unit 74 is an electric circuit that outputs the detection signal when the second electric signal indicating the presence of the powder of the developer G is input from the light receiving unit 73B of the detection unit 73.

When a plurality of detection units 73 are provided in the deterioration state detection unit 7, the output unit 74 corresponds to the detection unit 73 that outputs the second electric signal indicating the presence of powder of the developer G. The detection signal indicating the second threshold value (deterioration state of the developer G) is output.

Further, the ROM of the control unit 5 stores in advance a supply control program for causing the CPU to execute a supply control process (see the flowchart of FIG. 10) described later. Even if the supply control program is recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and is read from the recording medium and installed in a storage device such as EEPROM. Good.

Then, as shown in FIG. 2, the control unit 5 includes a supply control unit 51 and a correction processing unit 52. Specifically, the control unit 5 uses the CPU to execute the supply control program stored in the ROM. As a result, the control unit 5 functions as a supply control unit 51 and a correction processing unit 52.

The supply control unit 51 starts supplying the developer G to the developing unit 313 when the magnetic permeability of the developing agent G detected by the magnetic permeability sensor 313N becomes equal to or higher than a predetermined fifth threshold value.

For example, the supply control unit 51 determines whether or not the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N is equal to or higher than the fifth threshold value during the execution of the printing process. Then, when the supply control unit 51 determines that the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N is equal to or higher than the fifth threshold value, the supply control unit 51 controls the drive of the developer supply unit 316 to control the developer. The supply unit 316 is started to supply the developer G to the developing unit 313. For example, the supply control unit 51 causes the developer supply unit 316 to supply the developer G during the supply time set based on the difference between the detected magnetic permeability of the developer G and the fifth threshold value. The fifth threshold value may be arbitrarily set within a range in which image defects due to insufficient toner concentration in the developer G do not occur.

The correction processing unit 52 corrects the fifth threshold value based on the detection signal input from the deterioration state detection unit 7.

Specifically, when the detection signal is input from the deterioration state detection unit 7, the correction processing unit 52 subtracts a predetermined first specific value from the fifth threshold value to obtain a new fifth threshold value. By doing so, the fifth threshold value is corrected. The correction processing unit 52 may use the value obtained by multiplying the fifth threshold value by a predetermined second specific value as the new fifth threshold value.

The first specific value or the second specific value corresponds to each of the deteriorated states of the developer G when there are a plurality of the second threshold values (deteriorated states of the developing agent G) indicated by the detection signal. There may be more than one. In this case, the correction processing unit 52 uses the first specific value or the second specific value corresponding to the deterioration state of the developer G indicated by the detection signal input from the deterioration state detection unit 7. 5 Thresholds may be corrected.

[Supply control processing]
Hereinafter, an example of the procedure of the supply control process executed by the control unit 5 in the image forming apparatus 10 will be described with reference to FIG. Here, steps S11, S12 ... Represent the number of the processing procedure (step) executed by the control unit 5. The supply control process is executed together with the print process when the print process is executed in the image forming apparatus 10.

<Step S11>
First, in step S11, the control unit 5 determines whether or not the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N is equal to or higher than the fifth threshold value.

Here, when the control unit 5 determines that the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N is equal to or higher than the fifth threshold value (Yes side of S11), the process shifts to step S12. Further, if the magnetic permeability of the developer G detected by the magnetic permeability sensor 313N is not equal to or higher than the fifth threshold value (No side of S11), the control unit 5 shifts the process to step S13.

<Step S12>
In step S12, the control unit 5 controls the drive of the developer supply unit 316 to cause the developer supply unit 316 to start supplying the developer G to the developing unit 313. Here, the processes of steps S11 and S12 are executed by the supply control unit 51 of the control unit 5.

For example, the control unit 5 supplies the developer G to the developer supply unit 316 during the supply time set based on the difference between the magnetic permeability of the developer G detected in step S11 and the fifth threshold value. Let me.

<Step S13>
In step S13, the control unit 5 determines whether or not the detection signal has been input from the deterioration state detection unit 7.

Here, when the control unit 5 determines that the detection signal has been input from the deterioration state detection unit 7 (Yes side of S13), the control unit 5 shifts the process to step S14. Further, if the detection signal is not input from the deterioration state detection unit 7 (No side of S13), the control unit 5 shifts the process to step S15.

<Step S14>
In step S14, the control unit 5 corrects the fifth threshold value based on the detection signal input from the deterioration state detection unit 7. Here, the processes of steps S13 and S14 are executed by the correction processing unit 52 of the control unit 5.

Specifically, the control unit 5 corrects the fifth threshold value by using a value obtained by subtracting the first specific value from the fifth threshold value as the new fifth threshold value. As a result, due to the deterioration of the developer G, there is a gap between the target value of the toner concentration in the developing unit 313 and the actual toner concentration value in the supply control of the developer G using the magnetic permeability sensor 313N. It is avoided that it occurs.

<Step S15>
In step S15, the control unit 5 determines whether or not the printing process has been completed.

Here, when the control unit 5 determines that the printing process is completed (Yes side of S15), the control unit 5 ends the supply control process. If the printing process is not completed (No side of S15), the control unit 5 shifts the process to step S11.

As described above, in the image forming apparatus 10, the deterioration state detection unit 7 is provided with a rocking portion 72 that swings between the first position P3 and the second position P4 by the developer G falling from the opening 71B. ing. Therefore, it is not necessary to remove the developer G deposited on the rocking portion 72 from the rocking portion 72 by using a driving unit such as a motor. Therefore, it is possible to detect the deteriorated state of the developer G with a simple structure.

[Other Embodiments]
Hereinafter, the image forming apparatus 10 according to another embodiment of the present invention will be described with reference to FIG. Note that FIG. 11 is a side view showing the configurations of the swinging portion 72 and the detecting portion 73 of the image forming apparatus 10 according to another embodiment.

In other embodiments, the configurations of the swing unit 72 and the detection unit 73 are different from those in the above-described embodiment. The other configurations are common to the above-described embodiment and other embodiments. Therefore, in the following, only the configurations of the swing unit 72 and the detection unit 73 will be described.

The swinging portion 72 in the image forming apparatus 10 according to another embodiment can move between the third position P6 (see FIG. 11) and the fourth position P7 (see FIG. 11) below the third position P6. It is supported.

For example, the deterioration state detection unit 7 has a bearing unit 75 that rotatably supports the rotation shaft 723 of the swing unit 72. The bearing portion 75 has a pair of side wall portions that support the rotation shaft 723 of the swing portion 72, and a bottom plate portion on which each of the side wall portions is erected. The bearing portion 75 is movably supported in the vertical direction D1 by the housing 71. Further, the bearing portion 75 is urged upward by the urging members 71F to 71G (see FIG. 11). For example, one end of the urging members 71F to 71G is fixed to the housing 71, and the other end is fixed to the bottom plate portion of the bearing portion 75.

The rocking portion 72 is arranged at the third position P6 by its own weight in a state where the developer G is not deposited on the first receiving surface 721A1 and the second receiving surface 721A2. Further, the rocking portion 72 moves downward together with the bearing portion 75 according to the amount of the developer G deposited on the first receiving surface 721A1 or the second receiving surface 721A2. Then, the rocking portion 72 reaches the fourth position P7 when the amount of the developer G deposited on the first receiving surface 721A1 or the second receiving surface 721A2 exceeds the second threshold value. The bearing portion 75 is locked to move downward from the position corresponding to the fourth position P7 by a locking portion (not shown) provided in the housing 71. Here, the load applied to the rotating shaft 723 when the amount of the developer G deposited on the rocking portion 72 exceeds the second threshold value is an example of the fourth threshold value in the present invention.

Further, the detection unit 73 in the image forming apparatus 10 according to another embodiment is a sensor capable of detecting that the swing unit 72 has moved to the fourth position P7.

For example, the bottom plate portion of the bearing portion 75 is provided with a protruding piece 751 (see FIG. 11) that projects downward. Further, the detection unit 73 has a light emitting unit 73C and a light receiving unit 73D. The light emitting portion 73C and the light receiving portion 73D are arranged so as to face each other on the lower side of the bearing portion 75. The light emitting unit 73C emits light L2 toward the light receiving unit 73D. The light receiving unit 73D outputs a third electric signal according to the presence or absence of light reception of the light L2 emitted from the light emitting unit 73C. The light emitting unit 73C and the light receiving unit 73D are arranged at a position where the protruding piece 751 blocks the optical path of the light L2 when the rocking unit 72 is arranged at the fourth position P7. As a result, the detection unit 73 outputs the third electric signal according to whether or not the swing unit 72 has moved to the fourth position P7.

1 ADF
2 Image reading unit 3 Image forming unit 4 Paper feeding unit 5 Control unit 6 Operation display unit 7 Deterioration state detection unit 10 Image forming device 31 to 34 Image forming unit 51 Supply control unit 52 Correction processing unit 71 Housing 72 Swing unit 73 Detection part 74 Output part 313 Development part 316 Developer supply part 721 Accumulation part 721A Bottom plate part 721A1 First receiving surface 721A2 Second receiving surface 721B to 721C Side wall part 721D Partition part 722 Connection part 723 Rotating shaft

Claims (6)

The developer has a first receiving surface for receiving the developing agent discharged and dropped from the developing unit for developing an electrostatic latent image using a developing agent, and the developing agent is applied to the first receiving surface around the horizontal axis. It is swingably supported between a first position where it can be deposited and a second position where the developer can slide down from the first receiving surface, and is supported on the first receiving surface. A rocking portion that rotates from the first position to the second position when the rotational torque around the horizontal axis applied by the deposited developer exceeds a predetermined first threshold.
The center of gravity of the developer powder provided on the rocking portion and deposited on the first receiving surface is separated from the horizontal axis in response to an increase in the amount of the developing agent deposited on the first receiving surface. The displacement part of the center of gravity that is displaced in the first direction,
A detection unit that detects that the amount of deposit has exceeded a predetermined second threshold value, and
When the detection unit detects that the deposited amount exceeds the second threshold value, the output unit outputs a detection signal indicating the deterioration state of the developer corresponding to the second threshold value.
Equipped with a,
The center-of-gravity displacement portion is erected on the first receiving surface along a plane including the horizontal axis, and is in a second direction opposite to the first direction of the developing agent on the first receiving surface. It is a barrier that prevents you from moving to
The swinging portion has a second receiving surface for receiving the developing agent discharged and dropped from the developing portion on the second direction side of the displacement portion of the center of gravity, and the second receiving portion at the second position. The developer can be deposited on the retaining surface, and the developer can be slid down from the second receiving surface at the first position, and deposited on the second receiving surface. the developer by the deterioration state detecting device you rotate to the first position from the second position when the rotational torque exceeds a third predetermined threshold around the horizontal axis applied. The third threshold is the same as the first threshold.
The deterioration state detection device according to claim 1 . The detection unit is an optical sensor that detects the powder at a predetermined detection position above the rocking unit.
The deterioration state detection device according to claim 1 or 2 . The swinging portion is movably supported between the third position and the fourth position below the third position, and when the load applied to the horizontal axis exceeds a predetermined fourth threshold value. Moved from the third position side to the fourth position,
The detection unit is a sensor capable of detecting that the rocking unit has moved to the fourth position.
The deterioration state detection device according to any one of claims 1 to 3 . The deterioration state detection device according to any one of claims 1 to 4 ,
With the developing unit
An image forming apparatus comprising. The developer comprises a magnetic carrier and a non-magnetic toner.
The image forming apparatus includes a magnetic permeability sensor that detects the magnetic permeability of the developer in the developing unit, and a magnetic permeability sensor.
A supply control unit that starts supplying the developer to the developing unit when the magnetic permeability of the developing agent detected by the magnetic permeability sensor becomes equal to or higher than a predetermined fifth threshold value.
A correction processing unit that corrects the fifth threshold value based on the detection signal input from the deterioration state detection device, and
The image forming apparatus according to claim 5 .

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