JP2017181649A - Development device, process cartridge and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development device, a process cartridge and an image formation device with which the problem is reduced that winding of a sheet-like member on a winding shaft is not performed normally and use of the development device is begun in that state as is.SOLUTION: In order that a sheet-like member 13m forming a closed space inside a development device 13 where a developer G is accommodated is removed when its use is begun in an image information device body 1, a winding shaft 13k for winding the sheet-like member 13m is provided and a drive transmission mechanism for causing the winding shaft 13k to be rotated in a prescribed direction by a drive motor is provided. The drive transmission mechanism is constructed so that drive transmission from the drive motor is cut off after winding of the sheet-like member 13m is completed, causing the winding shaft 13k to stop rotating. Furthermore, there is provided a concentration detection sensor 40 (detection means) for detecting a state of winding of the sheet-like member 13m having been completed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof, and a developing device and a process cartridge installed therein.

  Conventionally, in a developing device that is detachably installed in an image forming apparatus such as a copying machine or a printer, the developer previously stored in a new developing device at the time of shipment from the factory does not leak out of the developing device during transportation. As described above, a technique is known in which a sheet-like member (shielding sheet, sealing sheet) that separates a space in which a developer is contained as a closed space is detachable (see, for example, Patent Documents 1 and 2).

Specifically, in the developing device that is mounted on the image forming apparatus main body and starts to be used, a closed space in which the developer is accommodated so that the developer that is accommodated (preset) in the interior does not leak to the outside. The sheet-like member which isolates an inside is formed so that may be formed.
Before the use of the image forming apparatus main body is started, the sheet-like member is moved in a direction substantially perpendicular to the width direction (longitudinal direction corresponding to the rotation axis direction of the developing roller), The sheet-like member is removed, and the developer is entirely accommodated in the developing device.
In this way, the developing process (image formation) can be performed by the developing device. That is, the developer accommodated in the developing device is stirred and mixed while being conveyed so as to circulate in the longitudinal direction by a plurality of conveying members such as a plurality of conveying screws. Part of the stirred and mixed developer is supplied to a developing roller (developer carrier). The developer carried on the developing roller is regulated to an appropriate amount by a doctor blade (developer regulating member) facing the developing roller, and then reaches a position facing the photosensitive drum (image bearing member). In this way, the latent image formed on the surface of the photosensitive drum is developed to form a toner image.

  On the other hand, in Patent Documents 1 and 2, a winding shaft that winds up a sheet-like member (shielding sheet, sealing sheet) is provided, and the winding shaft is rotated and driven together with the conveying member by a motor drive. Has been disclosed that automatically winds the sheet in a direction substantially perpendicular to the width direction. In particular, Patent Document 1 discloses that a sheet-like member is wound around a take-up shaft (sheet collecting shaft) for the purpose of reducing the driving torque of the drive motor after the winding operation of the sheet-like member (shielding sheet) is completed. A technique is disclosed in which a drive transmission stop mechanism is provided so that drive is not transmitted to the winding shaft after being taken.

  On the other hand, in Patent Document 3, the seal take-up shaft is manually rotated to wind the sealing seal member around the seal take-up shaft, and the developer contained in the developer containing portion is supplied into the developer housing. Techniques to do this are disclosed. And in patent document 3, it is judged whether the developing device is new by detecting the opaque processing part formed in the sealing seal member with the detection sensor installed just before the seal winding shaft. ing.

Since the techniques of Patent Documents 1 and 2 described above are configured to automatically wind the sheet-like member, the user-friendliness is improved as compared with the case where the sheet-like member is wound manually. Great effect can be expected.
However, if the sheet-shaped member is not normally wound around the winding shaft and the use of the developing device is started as it is, the normal image forming operation is not performed. .

  The present invention has been made to solve the above-mentioned problems, and the use of the developing device is started in a state in which the sheet-like member is not normally wound around the winding shaft. It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus that can reduce the problem.

  The developing device according to the present invention is a developing device that is detachably installed on the main body of the image forming apparatus, stores a developer therein, and develops a latent image formed on the surface of the image carrier, A sheet-like member that isolates the interior of the developing device so as to form a closed space in which the developer is contained so that the developer contained in the developing device does not leak to the outside; A winding shaft that winds up the sheet-like member with a winding direction rotating in a predetermined direction so that the sheet-like member is removed from the inside of the apparatus and intersecting the width direction of the sheet-like member; Drive is transmitted, the winding shaft is rotated in the predetermined direction to wind up the sheet-like member, and after the winding of the sheet-like member is completed, the drive transmission from the driving means is interrupted. Winding A drive transmission mechanism that rotates stop the axis, detecting means for detecting a state in which the winding has been completed the sheet-like member, those having a.

  According to the present invention, a developing device, a process cartridge, and the like that reduce the trouble that the use of the developing device is started as it is without the sheet-like member winding operation being normally performed on the winding shaft. An image forming apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows an image creation part. (A) The schematic sectional view which looked at the upper part of the developing device in the longitudinal direction, (B) The schematic sectional view which looked at the lower part of the developing device in the longitudinal direction. It is the schematic sectional drawing which looked at the circulation path of the developing device in the longitudinal direction. It is a schematic sectional drawing which shows the new image development apparatus at the time of factory shipment. FIG. 6 is a diagram illustrating an initial operation when a new developing device is mounted on the image forming apparatus main body. It is a perspective view which shows the principal part of a developing device from the side. It is a perspective view which shows the principal part of a developing device from the back side. It is the schematic which shows the state which the winding-up defect of the sheet-like member produced at the time of the initial stage operation | movement of a new developing apparatus. It is a schematic sectional drawing which shows the new image development apparatus at the time of factory shipment as a modification. As another modified example, (A) a schematic diagram showing a state in which the sheet-like member has been normally wound during the initial operation of a new developing device, and (B) a winding failure of the sheet-like member. FIG. 2 is a schematic diagram showing a state that has occurred.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the overall configuration and operation of the image forming apparatus 1 will be described with reference to FIG.
In FIG. 1, 1 is a tandem type color copier as an image forming apparatus, 3 is a document conveying unit that conveys a document to a document reading unit, 4 is a document reading unit that reads image information of the document, and 5 is an output image. A paper discharge tray, 7 is a paper feed unit for storing a recording medium P such as transfer paper, 9 is a registration roller (timing roller) for adjusting the conveyance timing of the recording medium P, and 11Y, 11M, 11C, and 11BK are each color ( Yellow, magenta, cyan, black) photoconductor drums as image carriers on which toner images are formed; 13 is a development for developing electrostatic latent images formed on the photoconductor drums 11Y, 11M, 11C, and 11BK; Reference numeral 14 denotes a primary transfer bias roller for transferring a toner image formed on each of the photoconductive drums 11Y, 11M, 11C, and 11BK while being superimposed on the recording medium P.
Reference numeral 17 denotes an intermediate transfer belt as an intermediate transfer body onto which toner images of a plurality of colors are transferred, and reference numeral 18 denotes a secondary transfer bias roller for transferring the color toner image on the intermediate transfer belt 17 onto the recording medium P. , 20 indicates a fixing device that fixes an unfixed image on the recording medium P, and 28 indicates a toner container in which toner of each color (yellow, cyan, magenta, black) to be supplied to the developing device 13 is accommodated.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described. Note that FIG. 2 can also be referred to for the image forming process performed on the photosensitive drums 11Y, 11M, 11C, and 11BK.
First, the document is transported from the document table by the transport rollers of the document transport unit 3 and placed on the contact glass of the document reading unit 4. Then, the document reading unit 4 optically reads the image information of the document placed on the contact glass.

  Specifically, the document reading unit 4 scans an image of a document on the contact glass while irradiating light emitted from an illumination lamp. Then, the light reflected from the original is imaged on the color sensor via the mirror group and the lens. The color image information of the original is read for each color separation light of RGB (red, green, blue) by the color sensor, and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by the image processing unit based on the RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information.

  Then, image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit. Then, a laser beam L (see FIG. 2) based on the image information of each color is emitted from the writing unit toward the corresponding photosensitive drums 11Y, 11M, 11C, and 11BK.

On the other hand, the four photosensitive drums 11Y, 11M, 11C, and 11BK are rotated clockwise in FIG. First, the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11BK are uniformly charged at a portion facing the charging unit 12 (see FIG. 2) (charging process). Thus, a charged potential is formed on the photosensitive drums 11Y, 11M, 11C, and 11BK. Thereafter, the surfaces of the charged photosensitive drums 11Y, 11M, 11C, and 11BK reach the irradiation positions of the respective laser beams.
In the writing unit, laser beams corresponding to the image signals are emitted from the four light sources corresponding to the respective colors. Each laser beam passes through a separate optical path for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  The laser beam corresponding to the yellow component is applied to the surface of the first photosensitive drum 11Y from the left side of the paper. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 11Y by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the surface of the photosensitive drum 11Y after being charged by the charging unit 12.

  Similarly, the laser beam corresponding to the magenta component is irradiated on the surface of the second photosensitive drum 11M from the left side of the paper, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is applied to the surface of the third photosensitive drum 11C from the left side of the drawing to form an electrostatic latent image of the cyan component. The black component laser light is applied to the surface of the fourth photoconductive drum 11BK from the left side of the drawing to form an electrostatic latent image of the black component.

Thereafter, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK on which the electrostatic latent images of the respective colors are formed reach the positions facing the developing device 13, respectively. Then, the respective color toners are supplied from the developing devices 13 onto the photosensitive drums 11Y, 11M, 11C, and 11BK, and the latent images on the photosensitive drums 11Y, 11M, 11C, and 11BK are developed (development process). .)
Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK after the development process reach the facing portions of the intermediate transfer belt 17, respectively. Here, a primary transfer bias roller 14 is installed at each facing portion so as to be in contact with the inner peripheral surface of the intermediate transfer belt 17. The toner images of the respective colors formed on the photosensitive drums 11Y, 11M, 11C, and 11BK on the intermediate transfer belt 17 at the position of the primary transfer bias roller 14 (the primary transfer nip) are sequentially. The primary transfer is repeated (primary transfer step).

Then, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK after the transfer process reach positions facing the cleaning unit 15, respectively. Then, the untransferred toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11BK is collected by the cleaning unit 15 (this is a cleaning process).
Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK pass through the static eliminating unit, and a series of image forming processes in the photoconductive drums 11Y, 11M, 11C, and 11BK is completed.

On the other hand, the intermediate transfer belt 17 (intermediate transfer member) on which the toners of the respective colors on the photosensitive drums 11Y, 11M, 11C, and 11BK are primarily transferred (carried) is run counterclockwise in the drawing, It reaches a position facing the secondary transfer bias roller 18. Then, the color toner image carried on the intermediate transfer belt 17 is secondarily transferred onto the recording medium P at a position facing the secondary transfer bias roller 18 (secondary transfer step).
Thereafter, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning unit. Then, the untransferred toner attached on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit, and a series of transfer processes in the intermediate transfer belt 17 is completed.

Here, the recording medium P transported between the intermediate transfer belt 17 and the secondary transfer bias roller 18 (secondary transfer nip) is transported from the paper supply unit 7 via the registration roller 9 and the like. It is a thing.
Specifically, the recording medium P fed by the paper feeding roller 8 from the paper feeding unit 7 that stores the recording medium P is guided to the registration roller 9 after passing through the conveyance guide. The recording medium P that has reached the registration roller 9 is conveyed toward the secondary transfer nip at the same timing.

Then, the recording medium P on which the full color image is transferred is guided to the fixing device 20 thereafter. In the fixing device 20, the color image is fixed on the recording medium P at the nip between the fixing roller and the pressure roller.
Then, the recording medium P after the fixing step is discharged as an output image outside the apparatus main body 1 by a discharge roller and stacked on the discharge tray 5 to complete a series of image forming processes.

Next, the image forming unit in the image forming apparatus will be described in detail with reference to FIGS.
FIG. 2 is a configuration diagram illustrating the image forming unit. FIG. 3A is a schematic cross-sectional view (horizontal cross-sectional view) of the upper portion of the developing device 13 (the position of the second transfer screw 13b2 as a recovery transfer member) as viewed in the longitudinal direction (width direction). FIG. 3B is a schematic cross-sectional view of the lower portion of the developing device 13 (the position of the first conveying screw 13b1 serving as a conveying member for supply) as viewed in the longitudinal direction. FIG. 4 is a schematic cross-sectional view (vertical cross-sectional view) of the circulation path of the developing device 13 in the longitudinal direction. In particular, FIG. 4A shows a developer in a normal developing process (image formation). FIG. 4B is a diagram showing the developing device 1 shipped from the factory and showing a state in which the developer is biased toward one end in the longitudinal direction by transportation. .
Since the image forming units for each color have almost the same structure, the alphabets (Y, C, M, BK) of symbols in each member constituting the image forming unit are appropriately removed in FIGS. And illustrated.

As shown in FIG. 2, the image forming unit includes a photosensitive drum 11 as an image carrier, a charging unit 12, a developing device 13 (developing unit), a cleaning unit 15, and the like.
A photoconductive drum 11 as an image carrier is a negatively charged organic photoconductor, and is rotationally driven clockwise by a main drive motor.

The charging unit 12 is a charging roller having elasticity in which a foamed urethane layer having a medium resistance in which a urethane resin, carbon black as conductive particles, a sulfurizing agent, a foaming agent, and the like are formed in a roller shape on a core metal. The material of the middle resistance layer of the charging unit 12 is urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber (NBR), silicone rubber, isoprene rubber, etc. It is also possible to use a rubber material in which a conductive material such as the above is dispersed or a foamed material of these materials.
The cleaning unit 15 is provided with a cleaning blade that is in sliding contact with the photosensitive drum 11, and mechanically removes and collects untransferred toner on the photosensitive drum 11.

  The developing device 13 is disposed such that a developing roller 13a as a developer carrying member is close to the photosensitive drum 11, and a developing region (developing) where the photosensitive drum 11 and the magnetic brush are in contact with each other. Nip) is formed. A developer G (two-component developer) composed of toner T and carrier C is accommodated in the developing device 13. The developing device 13 develops the electrostatic latent image formed on the photosensitive drum 11 (forms a toner image). The configuration and operation of the developing device 13 will be described in detail later.

Referring to FIG. 1, toner container 28 contains toner T to be supplied into developing device 13 therein. Specifically, development is performed from the toner container 28 via the toner transport tube based on information on the toner concentration (the ratio of the toner in the developer G) detected by the magnetic sensor installed in the developing device 13. The toner T is appropriately supplied from the toner supply port 13w toward the inside of the apparatus 13.
The supply of the toner T is not limited to the toner density information, but the image density information (for example, density detection described later) detected from the reflectance of the toner image formed on the photosensitive drum, the intermediate transfer belt, or the like. It is a detection result of the sensor 40.). Further, the implementation of the supply of the toner T may be determined by combining these different pieces of information.
In addition, the toner T (the toner in the developer G, the toner in the toner container 28) and the carrier C (the carrier in the developer G) used in the present embodiment are known ones. it can.

Hereinafter, the developing device 13 in the image forming apparatus will be described in detail.
2 to 4 and the like, the developing device 13 includes a developing roller 13a as a developer carrying member, conveying screws 13b1 and 13b2 (auger screws) as a plurality of conveying members, and a doctor blade as a developer regulating member. 13c, etc.
A developing roller 13a as a developer carrying member is rotated in a counterclockwise direction by a drive motor 51 as a driving means, which is a sleeve 13a2 formed of a nonmagnetic material such as aluminum, stainless steel, brass, or conductive resin in a cylindrical shape. It is comprised so that. Referring to FIG. 3, a magnet 13a1 that forms a plurality of magnetic poles on the peripheral surface (surrounding) of the sleeve 13a2 is fixed in the sleeve 13a2 of the developing roller 13a. The developer G carried on the developing roller 13a is conveyed as the developing roller 13a rotates in the direction of the arrow, and reaches the position of the doctor blade 13c. The developer G on the developing roller 13a is regulated to an appropriate amount at this position, and then conveyed to a position facing the photosensitive drum 11 (which is a developing region). The toner is attracted to the latent image formed on the photosensitive drum 11 by the electric field (developing electric field) formed in the developing area.

  Specifically, the pumping magnetic pole acts on a carrier as a magnetic body, and the developer G accommodated in the supply transport path is pumped onto the developing roller 13a. Part of the developer G carried on the developing roller 13a is scraped off at the position of the doctor blade 13c and returned to the supply conveyance path. On the other hand, the developer G carried on the developing roller 13a through the doctor gap between the doctor blade 13c and the developing roller 13a at the position of the doctor blade 13c where the magnetic force by the pumping magnetic pole acts is at the position of the main magnetic pole. It rises and becomes a magnetic brush in the developing area and slides on the photosensitive drum 11. Thus, the toner T in the developer G carried on the developing roller 13 a adheres to the latent image on the photosensitive drum 11. Thereafter, the developer G that has passed the position of the main magnetic pole is transported to the position of the agent separation magnetic pole by the plurality of transport magnetic poles. Then, a repulsive magnetic field (a magnetic field acting in a direction away from the developing roller 13a) acts on the carrier at the position of the agent separating magnetic pole, and the developer G after the developing process carried on the developing roller 13a becomes It is detached from the developing roller 13a. The detached developer G falls into the recovery transport path and is transported downstream of the recovery transport path by the second transport screw 13b2.

  Referring to FIG. 2 and the like, the doctor blade 13c as a developer regulating member is a non-magnetic plate-like member disposed below the developing roller 13a (a part of which can be formed of a magnetic material). It is.

The developing roller 13a rotates counterclockwise in FIG. 2, and the photosensitive drum 11 rotates clockwise in FIG.
The two conveying screws 13b1 and 13b2 (a plurality of conveying members) are stirred and mixed while circulating and conveying the developer G accommodated in the developing device 13 in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 2). To do.
The first conveying screw 13b1 (supplying conveying member) as the first conveying member is disposed at a position facing the developing roller 13a, and horizontally conveys the developer G in the longitudinal direction (rotational axis direction) ( In addition, the developer G is supplied onto the developing roller 13a at the position of the pumping magnetic pole (the supply in the direction indicated by the white arrow in FIG. 3B). .) The first transport screw 13b1 rotates in the clockwise direction in FIG.

A second conveyance screw 13b2 (collection conveyance member) as a second conveyance member is disposed above the first conveyance screw 13b1 and at a position facing the developing roller 13a. Then, the developer G released from the developing roller 13a (the developer G forcibly released from the developing roller 13a by the agent separating magnetic pole after the developing process, and released in the direction of the white arrow in FIG. 3A). Is transported horizontally in the longitudinal direction (the transport in the right direction indicated by the broken-line arrow in FIG. 3A). In the present embodiment, the rotation direction of the second conveying screw 13b2 is set to be the same direction (the counterclockwise direction in FIG. 2) with respect to the rotation direction of the developing roller 13a.
Then, the second transport screw 13b2 secondly supplies the developer G circulated from the downstream side of the transport path by the first transport screw 13b1 via the first relay portion 13s to the upstream side of the transport path by the first transport screw 13b1. It conveys via the relay part 13t (it is the conveyance shown by the dashed-dotted arrow of FIG. 3).
The two conveying screws 13b1 and 13b2 are arranged so that the rotation shaft is substantially horizontal, like the developing roller 13a and the photosensitive drum 11. Moreover, as for the two conveyance screws 13b1 and 13b2, both have a screw part spirally wound around the shaft part.

The two transport screws 13b1 and 13b2 form a drive system by a gear train together with the developing roller 13a, and are configured to be rotationally driven by a drive motor 51 as a drive unit. That is, when the drive motor 51 is driven and controlled by the control unit 50, the two conveying screws 13b1 and 13b2 are rotationally driven together with the developing roller 13a.
The main parts of the two conveying screws 13b1 and 13b2 (a plurality of conveying members) are installed inside the developing device 13, and are driven in the forward direction (in the direction of the arrow in FIG. 2) by the driving motor 51 (driving means) during the developing process. The developer G that is rotationally driven at a predetermined rotational speed and is accommodated in the developing device 13 is circulated and conveyed. The developing roller 13a is rotationally driven together with the two conveying screws 13b1 and 13b2 (a plurality of conveying members) by a driving motor 51 (driving means).

More specifically, the developing roller 13a is directly driven (driving force) from the driving motor 51 to the shaft portion on one end side in the width direction (the vertical direction in FIG. 2 and the left-right direction in FIG. 3). A coupling is provided for transmission. In addition, a gear is installed on the shaft portion on one end side in the width direction of the developing roller 13a, and this gear meshes with a gear installed on the shaft portion on one end side in the width direction of the first conveying screw 13b1. In addition, a first gear 13e is installed on the shaft portion on the other end side in the width direction of the first transport screw 13b1, and this first gear 13e is connected to the shaft portion on the other end side in the width direction of the second transport screw 13b2. It meshes with the installed second gear 13f (see FIGS. 7 and 8). Here, the second gear 13f (driving side gear) is configured to be able to mesh with a third gear 13g (driven side gear) installed on the winding shaft 13k. This will be described in detail later. .
In the present embodiment, the drive motor 51 (drive means) that drives the developing device is provided as a development drive motor independently of the main drive motor that rotationally drives the photosensitive drum 11 and the like. The driving motor 51 (driving means) for driving the developing device is a forward / reverse bidirectional rotation type motor and a rotation speed variable type motor.

Here, the conveyance path (supply conveyance path) by the first conveyance screw 13b1 and the conveyance path (collection conveyance path) by the second conveyance screw 13b2 are separated from each other by the wall (partition 13d).
Referring to FIGS. 3 and 4A, the downstream side of the transport path (collection transport path) by the second transport screw 13b2, and the upstream side of the transport path (supply transport path) by the first transport screw 13b1 Are communicated via the second relay portion 13t. The developer G that has reached the downstream side of the collection conveyance path by the second conveyance screw 13b2 falls by its own weight at the second relay portion 13t and reaches the upstream side of the supply conveyance path.
3 and 4A, the downstream side of the conveyance path by the first conveyance screw 13b1 and the upstream side of the conveyance path by the second conveyance screw 13b2 are connected via the first relay portion 13s. Communicate. Then, the developer G that has not been supplied onto the developing roller 13a in the supply conveyance path by the first conveyance screw 13b1 stays in the vicinity of the first relay portion 13s and rises up, and passes through the first relay portion 13s. It is transported (supplied) to the upstream side of the transport path for collection by the two transport screws 13b2.
In addition, in order to improve the developer transportability in the first relay section 13s (delivery of the developer against the direction of gravity from the supply transport path to the collection transport path), the first transport screw 13b1 is provided. A paddle-shaped portion or a screw portion in which the screw winding direction is formed in the reverse direction can also be provided at a downstream position (a position corresponding to the first relay portion 13s).

  With such a configuration, a circulation path for circulating the developer G in the longitudinal direction in the developing device 13 is formed by the two conveying screws 13b1 and 13b2. That is, when the developing device 13 is operated, the developer G accommodated in the device flows in the direction of the broken arrow in FIGS. 3 and 4A. Thus, the developer G supply path to the developing roller 13a (the transport path for supply by the first transport screw 13b1) and the developer G recovery path (second transport screw) separated from the developing roller 13a. 13b2), the density deviation of the toner image formed on the photosensitive drum 11 can be reduced.

A magnetic sensor for detecting the toner concentration of the developer circulating in the apparatus is installed in the conveyance path by the second conveyance screw 13b2. Then, based on the toner density information detected by the magnetic sensor, the toner container 28 is directed into the developing device 13 through the toner supply port 13w (located in the vicinity of the first relay portion 13s). New toner T is supplied.
3 and 4A, the toner replenishing port 13w is located upstream of the upstream side of the transport path by the second transport screw 13b2 and away from the development area (the longitudinal direction of the development roller 13a). Outside the range of directions.). By installing the toner replenishing port 13w in the vicinity of the first relay portion 13s in this way, the developer that has separated from the developing roller 13a descends from above the replenishment toner having a small specific gravity in the collection conveyance path, and the collection conveyance path. The replenishment toner can be sufficiently dispersed and mixed with respect to the developer over a relatively long time toward the downstream side.
In the present embodiment, the toner replenishing port 13w is disposed in the collection transport path by the second transport screw 13b2, but the position of the toner replenishing port 13w is not limited to this, and for example, the transport for supply It can also be arranged above the upstream side of the path.

Hereinafter, a characteristic configuration and operation of the developing device 13 according to the present embodiment will be described.
The developing device 13 in the present embodiment is detachably (replaceable) with respect to the image forming apparatus main body 1 and is replaced with a new one (including a recycled product) in a predetermined replacement cycle. .
Here, referring to FIG. 5, the developing device 13 in the present embodiment includes a developer G (preliminary at the time of factory shipment) stored in the developing device 13 until use in the image forming apparatus main body 1 is started. The sheet-like member 13m that isolates the inside is provided so that a closed space in which the developer G is accommodated is formed in the developing device 13 so that the developer G that is packed is not leaked to the outside. ing.
Further, the developing device 13 has a predetermined direction (counterclockwise in FIG. 6B) so that the sheet-like member 13m is removed from the inside of the developing device 13 when the image forming apparatus main body 1 is used. And a winding shaft 13k that winds the sheet-like member 13m with a direction (substantially orthogonal) intersecting the width direction of the sheet-like member 13m as a winding direction.

  Specifically, the sheet-like member 13m is made of a transparent resin material such as an OHP sheet having a thickness of about 0.1 to 0.5 mm, Mylar, and the winding direction (the white arrow direction in FIG. 6B). ) To extend in a substantially rectangular shape. The sheet-like member 13m is set to have a length in the width direction in accordance with the range in the width direction so that the inside of the developing device 13 can be isolated. The length in the winding direction is set sufficiently long so that winding can be performed.

Then, a new developing device 13 (including a recycled product) is shipped from the factory with the sheet-like member 13m installed as shown in FIG. That is, in the factory, the developer G is inside the developing device 13 (or the developing device before the developing roller 13a is assembled) in a state where the assembly is completed (the supply conveyance path and the collection conveyance path). After the filling, the sheet-like member 13m is installed so as to seal the supply conveyance path and the collection conveyance path so that the developer G does not leak.
Specifically, with reference to FIG. 5, in the present embodiment, the sheet-like member 13 m has a longitudinal direction between the tip of the partition portion 13 d and the tip of the doctor blade 13 c in the developing device 13. It is formed so as to cover the entire region (the range between the inner wall on one end side in the longitudinal direction of the developing case and the inner wall on the other end side in the longitudinal direction). Then, the vicinity of the end of the sheet-like member 13m on the doctor blade 13c side is bonded (or thermally welded) to the developing device 13 (in this embodiment, the tip of the doctor blade 13c) with a relatively light force. Then, the other end portion of the sheet-like member 13m is wound around the take-up shaft 13k, and tension is applied to the sheet-like member 13m. Thereby, the developer is prevented from leaking out from the first conveying screw 13b1 (supply screw) side.
Similarly, in the developing device 13, the sheet-like member 13m is located between the front end of the partition portion 13d and the opening 13r1 (or the take-up shaft 13k) in the entire longitudinal direction (one end side in the longitudinal direction of the developing case). And the inner wall on the other end side in the longitudinal direction). The developer is prevented from leaking from the second conveying screw 13b2 (collection screw) side by the tension of the sheet-like member 13m. Then, in addition to the distal end portion of the doctor blade 13c, the distal end portion of the partition portion 13d is bonded (or thermally welded) with a relatively light force, thereby further improving the sealing performance.
In the present embodiment, the vicinity of the end portion of the sheet-like member 13m on the doctor blade 13c side is bonded to the tip end portion of the doctor blade 13c, but the end portion of the sheet-like member 13m on the doctor blade 13c side is bonded to the developing device. It is also possible to adhere to the outside of 13 (for example, the exposed surface of the doctor blade 13c or the developing case).

Further, referring to FIG. 5 (or FIGS. 7 and 8), etc., the ceiling portion of the developing case 13r that functions as the exterior or casing of the developing device 13 (with respect to the inside where the developer G is accommodated in the developing device 13). On the outside, the winding shaft 13k is rotatably installed. Then, by rotating the take-up shaft 13k, the sheet-like member 13m can be taken up on the outer periphery of the take-up shaft 13k. Are fixed by bonding or the like.
Further, as shown in FIG. 5, a substantially rectangular opening 13r1 communicating from the inside of the developing device 13 to the outside is formed in the ceiling portion of the developing case 13r, and the sheet-like member 13m is formed through the opening 13r1. Is configured to be movable (wound up) from the inside of the developing device 13 toward the outside.

The developing device 13 configured as described above has an image forming apparatus as shown in FIG. 6 with the developer G accommodated therein by the sheet-like member 13m sealed and encapsulated as shown in FIG. It will be attached to the main body 1. As such a mode, (1) a new image forming apparatus main body 1 is shipped with a new developing device 13 mounted, and (2) it is already used by a user. There is a case where a new (replacement) developing device 13 is attached to the image forming apparatus main body 1.
In any of the cases described above, the new developing device 13 is in a sealed / sealed state by rotating the winding shaft 13k before the use (development process) in the image forming apparatus 1 is started. The sheet-like member 13m is wound around the winding shaft 13k. That is, as shown in FIG. 6B, the image forming operation (developing process) is performed in a state where the developing device 13 in which the sealed sheet-like member 13m is installed is mounted on the image forming apparatus main body 1. Before starting, by rotating the take-up shaft 13k, the sheet-like member 13m is moved in the direction of the white arrow and taken up by the take-up shaft 13k, and normal image formation is performed in the state shown in FIG. A process (development process) will be performed.

Here, in this Embodiment, the winding shaft 13k is formed with the metal material whose diameter is about 3-6 mm.
Further, in the present embodiment, as shown in FIG. 5, the sheet-like member 13m is wound around a flat portion 13r2 (upper part is covered with a cover member) formed in a part of the developing case 13r. It is configured to function as a part of the winding path. That is, the winding path is formed such that a part (the flat surface portion 13r2) thereof is along the developing case 13r.

  As described above, in this embodiment, even when the developing device 13 is transported (carried) as a replacement, the developing device 13 is mounted on the image forming apparatus main body 1 at the time of shipment. Even when transported, since the developer G stored in advance in the developing device 13 is sealed by the sheet-like member 13m, the developer G is stored in the interior due to vibration or the like generated during transport. The problem that the developer G leaks to the outside of the developing device 13 can be prevented.

In particular, in the present embodiment, as shown in FIG. 5, the sheet-like member 13m has a developing roller 13a (developer carrier) in the developing device 13 in a state before the winding by the winding shaft 13k is started. ) Is provided so as to form a closed space.
Thereby, since the developer G is not carried on the surface of the developing roller 13a during transportation, it is possible to reliably prevent the user from touching the surface of the developing roller 13a and getting dirty with the developer G. Even when a new developing device 13 is installed in a new image forming apparatus main body 1 and shipped from the factory, the surface of the photosensitive drum is damaged by the developer G carried on the surface of the developing roller 13a during transportation. It is possible to prevent problems that may occur.

In this embodiment, as shown in FIGS. 2 and 5, an opening 13 r 1 for removing the sheet-like member 13 m from the inside of the developing device 13 is formed in the ceiling portion of the developing case 13 r that is not buried in the developer G. Has been. Accordingly, it is possible to make it difficult for the developer G to leak from the opening 13r1 during normal image formation as compared with the case where the opening is formed on the side of the developing case 13r buried in the developer G.
In the present embodiment, in order to further reliably reduce the leakage of the developer G from the opening 13r1 as described above, the sheet-like member 13m and the opening 13r1 are not disturbed without interrupting the winding operation of the sheet-like member 13m. A sealing material 13n that seals the gap is provided in the opening 13r1. The sealing material 13n is formed of an elastic material such as polyurethane foam, and has a slit corresponding to the width of the sheet-like member 13m.

Here, driving (driving force) is transmitted from the driving motor 51 (driving means) to the developing device 13 in the present embodiment, and the winding 13k axis is set in a predetermined direction (counterclockwise in FIG. 6). Drive transmission mechanisms 13g, 13h for rotating and winding the sheet-like member 13m and stopping the rotation of the take-up shaft 13k by interrupting the drive transmission from the drive motor 51 after the winding of the sheet-like member 13m is completed. 13p and 13q are provided.
That is, in the present embodiment, the winding shaft 13k is driven by the driving motor 51 after the driving (driving force) is transmitted from the driving motor 51 and rotated in a predetermined direction to complete the winding of the sheet-like member 13m. The transmission of (driving force) is cut off and the rotation is stopped.

With reference to FIGS. 7 and 8, the mechanism for interrupting the drive transmission from the drive motor 51 to the take-up shaft 13k after the completion of the take-up will be described in detail.
As described above, the developing device 13 is rotated by the driving force transmitted from the driving motor 51 for the developing device 13 via the gear train to the second conveying screw 13b2 (one of the plurality of conveying members). Member). The take-up shaft 13k is provided with a third gear 13g as a driven gear that meshes with a second gear 13f as a drive side gear installed in the second transport screw 13b2. Further, the take-up shaft 13k is screwed into a female screw portion 13p (nut) fixed to the ceiling portion of the developing device 13 to move the take-up shaft 13k in the axial direction (width direction). The part 13q is formed in a part in the axial direction.

Then, when the driving force is transmitted from the second gear 13f (driving side gear) to the third gear 13g (driven side gear) and the winding shaft 13k rotates, the feed screw portion 13q and the female screw portion 13p are screwed together. The winding shaft 13k moves in the axial direction (the arrow direction in FIGS. 7 and 8 and the width direction), and the winding of the sheet-like member 13m onto the winding shaft 13k is completed. The meshing between the second gear 13f and the third gear 13g is released, and the winding shaft 13k stops rotating. That is, the screwing of the feed screw portion 13q and the female screw portion 13p advances, the third gear 13g slides in the axial direction together with the winding shaft 13k, and the third gear 13g does not mesh with the second gear 13f ( When reaching the disengagement position), the transmission of the driving force is interrupted and the winding shaft 13k stops rotating. In order to achieve such an operation, the tooth width and rotation speed (number of teeth) of the two gears 13f and 13g, the screwing position and screwing length of the feed screw portion 13q and the female screw portion 13p, etc. Is set.
Thus, members such as the third gear 13g, the female screw portion 13p, and the feed screw portion 13q function as a drive transmission mechanism.

  After winding the sheet-like member 13m in this way, the winding shaft 13k is permanently driven in conjunction with the driving of the developing device 13 by stopping the rotation of the winding shaft 13k. Therefore, it is possible to suppress the problem that abnormal noise is generated or the driving torque is constantly kept large. Further, since the rotation of the take-up shaft 13k is stopped when the normal image forming operation is started, it is possible to suppress a problem that the vibration caused by the rotation of the take-up shaft 13k affects the image formation.

Further, the driving of the developing roller 13a and the conveying screws 13b1 and 13b2 is cut off by using the driving force of the driving motor 51 that drives the developing device 13 without providing a motor for driving the winding shaft 13k independently. Therefore, it becomes possible to cut off only the drive of the winding shaft 13k. Therefore, the developing device 13 can be reduced in size and weight.
In the present embodiment, the third gear 13g (driven gear) installed on the winding shaft 13k is configured to mesh with the second gear 13f installed on the second conveying screw 13b2, but drive transmission is performed. However, for example, the gear (driven gear) installed on the winding shaft 13k may be configured to mesh with the first gear 13e installed on the first conveying screw 13b1. it can.

Here, referring to FIG. 6, in the present embodiment, the drive transmission mechanisms 13g, 13h, 13p, and 13q have two conveying screws 13b1 and 13b2 (a plurality of conveying members) driven by a driving motor 51 (driving means). When rotating in the forward direction (in the direction of the arrows in FIGS. 6A and 6C), the take-up shaft 13k is idled, and the drive motor 51 causes the two conveying screws 13b1 and 13b2 to move in the forward direction. When rotating in the reverse direction (in the direction of the arrow in FIG. 6B), the winding shaft 13k is configured to rotate in a predetermined direction (in the counterclockwise direction in FIG. 6B). ing.
That is, the winding shaft 13k rotates idle when the two conveying screws 13b1 and 13b2 are rotated in the forward direction by the drive motor 51, and the two conveying screws 13b1 and 13b2 are rotated in the opposite direction by the driving motor 51. When rotating, it is configured to rotate in a predetermined direction.
In other words, as shown in FIGS. 2, 6A, and 6C, when the developing device 13 is driven in the forward direction by the driving motor 51, driving (driving force) is transmitted to the winding shaft 13k. Instead, the winding shaft 13k stops rotating. On the other hand, as shown in FIG. 6B, when the developing device 13 is driven in the reverse direction by the drive motor 51, the drive (driving force) is transmitted to the take-up shaft 13k, and the take-up shaft 13k. Is rotated in the direction of the arrow, and a winding operation is performed.

  Specifically, a drive motor 51 (development drive motor) as a drive means for driving the developing device 13 is used that can rotate in both forward and reverse directions. As described above, with reference to FIGS. 7 and 8, the second gear 13f (driving side gear) installed on the second conveying screw 13b2 has a third gear installed on the winding shaft 13k. The gear 13g (driven gear) is engaged. When the third gear 13g rotates in the forward direction (clockwise in FIG. 6) following the second gear 13f that rotates in the forward direction, the winding shaft 13k is provided on the inner diameter portion of the third gear 13g. When the third gear 13g rotates in the reverse direction (counterclockwise in FIG. 6) following the second gear 13f rotating in the opposite direction without transmitting the rotation to the winding shaft 13k. A one-way clutch 13h for transmission is inserted.

  With this configuration, as shown in FIG. 6B, when the sheet-like member 13m is wound up by the take-up shaft 13k at the start of use of the new developing device 13, the developing device 13 is reversed by the drive motor 51. When the third gear 13g is rotated counterclockwise, the rotation is transmitted to the winding shaft 13k via the one-way clutch 13h (the winding shaft 13k rotates and the sheet-like member 13m rotates). Is wound up). On the other hand, during normal image formation, the developing device 13 is rotated forward by the drive motor 51 and the third gear 13g is rotated clockwise, so that the one-way clutch 13h rotates the winding shaft 13k. Is not transmitted (the third gear 13g idles and the winding shaft 13k stops rotating). Thus, the one-way clutch 13h also functions as a member constituting the drive transmission mechanism.

  As described above, when the sheet-like member 13m is wound, the developing roller 13a and the conveying screws 13b1 and 13b2 are also driven, and the developing roller 13a having an uneven surface vibrates the sheet-like member 13m. The developer adhering to the top is removed. Furthermore, the tip of the partition part 13d and the opening 13r1 (seal material 13n) through which the sheet-like member 13m passes respectively scrape off the developer attached to the surface of the sheet-like member 13m.

  When the developing device 13 in the present embodiment starts to be used in the image forming apparatus main body 1, the two conveying screws 13b1 and 13b2 (and the developing roller 13a) are reversed by the driving motor 51 (driving means). The sheet-like member 13m is wound up by the winding shaft 13k by being rotationally driven in the direction (the arrow direction in FIG. 6B).

Specifically, in the present embodiment, when the use of the developing device 13 is started in the image forming apparatus main body 1, the two conveying screws 13 b 1 and 13 b 2 (and the developing roller 13 a) are predetermined in the forward direction by the drive motor 51. Until the winding of the sheet-like member 13m is completed by at least the winding shaft 13k. The two drive screws 13b1 and 13b2 (and the developing roller 13a) are rotationally driven in the opposite direction by the drive motor 51 at a rotational speed smaller than a predetermined rotational speed (the rotational speed during the normal developing process). As described above, it is controlled by the control unit 50.
As a result, even if the developer G accommodated in the developing device 13 is biased toward one end in the longitudinal direction, the winding operation of the sheet-like member 13m is performed well without increasing the starting torque of the drive motor 51. be able to.

  More specifically, when a new developing device 13 is mounted on the image forming apparatus 1 (or when operation of the new image forming apparatus 1 with the new developing device 13 mounted is started), During a warm-up operation in which image conditions are adjusted, first, as shown in FIG. 6A, the developing device 13 is driven in the forward direction at a low speed for a predetermined time. At this time, since the drive is not transmitted to the take-up shaft 13k, the take-up operation of the sheet-like member 13m is not performed, and the two conveying screws 13b1 and 13b2 are driven at a low rotational speed to circulate in the developing device 13. The developer G is circulated slowly in the path.

Therefore, when the developing device 13 shipped from the factory toward the user is transported in a state of being inclined in the longitudinal direction, it is accommodated inside the developing device 13 as shown in FIG. Even if the developer G is biased toward one end in the longitudinal direction, such development can be achieved without increasing the starting torque of the drive motor 51 by the two conveying screws 13b1 and 13b2 that are rotationally driven at a low rotational speed. The developer G is circulated slowly so that the unevenness of the agent G is eliminated.
That is, as shown in FIG. 4B, in the state where the developer G accommodated in the developing device 13 is biased toward one end in the longitudinal direction, the winding shaft 13k is conveyed to the transport screw 13b1, by the drive motor 51. If it is rotationally driven with normal rotation together with 13b2, the starting torque of the drive motor 51 becomes large, and winding failure of the sheet-like member 13m occurs. On the other hand, in the present embodiment, immediately after the new developing device 13 is set in the image forming apparatus main body 1, the sheet-like member 13m is not immediately wound by the winding shaft 13k. Since the developing device 13 is driven at a low speed in a state where the drive transmission to the winding shaft 13k is cut off, such a state is resolved even when the developer G is biased. Thus, it is possible to prevent the winding failure of the sheet-like member 13m due to an increase in driving torque.
Note that the time (predetermined time) during which the developing device 13 is driven at a low speed as shown in FIG. 6 (A), even if there is a bias of the developer G as shown in FIG. 4 (B), the bias is the transport screw 13b1. , 13b2 is set to a time that can be sufficiently eliminated.

Then, during the warm-up operation, after the forward low speed rotation of the developing device 13 as shown in FIG. 6A is performed for a predetermined time, the drive motor 51 is rotated at a low speed as shown in FIG. 6B. By driving in the reverse direction for a predetermined time, the drive is transmitted to the winding shaft 13k, and the two conveying screws 13b1 and 13b2 are driven at a low rotational speed while the sheet-like member 13m is wound. Thus, the developer G is slowly circulated in the reverse direction in the circulation path in the developing device 13. At this time, the winding operation of the sheet-like member 13m by the winding shaft 13k is performed by the two conveying screws 13b1 and 13b2 that are rotationally driven at a low rotational speed without increasing the starting torque of the driving motor 51 so much. become. The time for which the drive motor 51 is driven in the reverse direction in this way is set to a time during which the winding operation of the sheet-like member 13m is sufficiently performed by the winding shaft 13k.
Then, as shown in FIG. 6C, after the winding of the sheet-like member 13m is completed (after the state shown in FIG. 2), the developing device 13 can normally perform the developing process in the warm-up operation. In order to perform the remaining operations (for example, image density adjustment) that should be performed after reaching the state, the developing device 13 is driven in the forward direction by normal rotation by the drive motor 51. At this time, since the drive is not transmitted to the winding shaft 13k, the generation of noise and the influence on the image due to the rotation of the winding shaft 13k are suppressed.
Then, after the warm-up operation is completed, a normal image forming process (development process) as described above with reference to FIGS. 1 and 2 is performed.

  Here, the developing device 13 in the present embodiment is provided with a density detection sensor 40 as detection means for detecting a state in which the winding of the sheet-like member 13m is completed. The density detection sensor 40 as the detection means optically detects a state in which the image density of the toner image formed on the photosensitive drum 11 by the developing device 13 has reached a predetermined threshold value. A known reflection type photosensor (P sensor) including an element and a light receiving element can be used. In the present embodiment, the density detection sensor 40 is installed in the developing case 13r (developing device 13) so as to face the downstream side of the developing region (developing nip portion) with respect to the photosensitive drum 11, but the photosensitive member. If it is installed downstream of the development area (development nip portion) with respect to the drum 11 and opposed to the upstream side of the primary transfer nip, the density detection sensor 40 is connected to the development case 13r (development device 13). It does not have to be installed integrally.

  When the use of the developing device 13 is started in the image forming apparatus main body 1, the winding shaft 13k is rotated by the drive motor 51 (drive means), and the sheet-like member is detected by the density detection sensor 40 (detection means). When the state where the winding of 13m is completed is detected, the use is started, and when the state where the winding of the sheet-like member 13m is not detected by the density detection sensor 40, the start of the use is interrupted. Further, the drive motor 51 is controlled by the control unit 50 based on the information sent from the density detection sensor 40.

Specifically, in the warm-up operation described above, after driving the drive motor 51 in the reverse direction for a predetermined time as shown in FIG. 6B, the developing device 13 is driven by the drive motor 51 as shown in FIG. 6C. The toner image (substantially rectangular shape) formed on the photosensitive drum 11 by performing the image forming process (described previously with reference to FIGS. 1 and 2) while driving the toner in the forward direction with normal rotation. The image density of the patch pattern is detected by the density detection sensor 40.
When the image density detected by the density detection sensor 40 has reached a predetermined threshold value (when a toner image having a sufficient image density is formed), a sheet-like member is formed on the winding shaft 13k. Assuming that 13m is normally wound up and the sheet-like member 13m does not remain in the developing device 13, a normal image forming process (developing step) is performed as it is.

On the other hand, when the image density detected by the density detection sensor 40 does not reach a predetermined threshold value (when a toner image having a sufficient image density is not formed), as shown in FIG. Further, assuming that the sheet-like member 13m is not normally wound on the take-up shaft 13k and the sheet-like member 13m remains in the developing device 13, the normal image forming process (developing step) is not performed as it is. Then, the operation of the developing device 13 (image forming apparatus 1) is interrupted (the drive is stopped).
Then, it is notified that the winding of the sheet-like member 13m has not been completed. That is, when the state where the winding of the sheet-like member 13m is not detected is detected by the density detection sensor 40 (detecting means), the fact that the winding of the sheet-like member 13m is not completed is notified. Specifically, the display panel 52 (display unit) installed on the exterior of the apparatus main body 1 says, “The sheet-like member of the developing device is not wound correctly. Message will be displayed. Thereby, the user can surely recognize the winding failure of the sheet-like member 13m.

Then, a procedure for completing the winding of the sheet-like member 13m (recovery means) is displayed on the display panel 52. That is, when the density detection sensor 40 (detection means) does not detect the completion of the winding of the sheet-like member 13m, a procedure for completing the winding of the sheet-like member 13m is displayed on the display panel 52 as a display unit. Will do.
Specifically, on the display panel 52 (display unit) installed in the exterior part of the apparatus main body 1, “According to the illustrated procedure, take out the developing device from the apparatus and manually remove the sheet-like member. In such a case, please contact a service person. " As a result, the user can resolve the winding failure of the sheet-like member 13m and resume the normal image forming process.

  As described so far, the developing device 13 in the present embodiment is configured to automatically wind up the sheet-like member 13m, and thus is configured to wind up the sheet-like member 13m manually. Compared with, user convenience can be improved. Further, since the density detection sensor 40 (detection means) for detecting the winding failure of the sheet-like member 13m is provided, the winding operation of the sheet-like member 13m around the winding shaft 13k is not normally performed and In this state, the use of the developing device 13 is started, so that a problem that a normal image forming operation is not performed can be surely reduced.

In the present embodiment, the density detection sensor 40 is used as detection means for detecting a state in which the winding of the sheet-like member 13m is completed.
On the other hand, as a detection means for detecting a state in which the winding of the sheet-like member 13m is completed, a torque detection sensor 41 (FIG. 2) for detecting a state in which the change in the drive torque of the drive motor 51 is greater than a predetermined value. Can also be used. As the torque detection sensor 41, a known sensor can be used. For example, a sensor that detects a change in the drive torque from a change in the magnitude of the current flowing through the drive motor 51 can be used.
In the warming-up operation described above, the drive motor 51 is driven in the reverse direction for a predetermined time as shown in FIG. 6B, and the drive torque from the start to the end of the drive is detected by the torque detection sensor. 41.
When the change in the driving torque detected by the torque detection sensor 41 is larger than a predetermined value, the sheet-like member 13m is normally wound around the take-up shaft 13k, and the sheet-like member 13m is placed in the developing device 13. A normal image forming process (development process) is performed as it is, assuming that the sheet-like member 13m wound around the winding shaft 13k does not remain and is not in tension. On the other hand, when the change in the driving torque detected by the torque detection sensor 41 is smaller than a predetermined value, the sheet-like member 13m is normally wound around the winding shaft 13k as shown in FIG. Assuming that the sheet-like member 13m remains in the developing device 13 and the sheet-like member 13m wound around the take-up shaft 13k is under tension, a normal image forming process (development process) ), The operation of the developing device 13 (image forming apparatus 1) is interrupted (driving is stopped).

<Modification 1>
In the present embodiment, in the operation of FIG. 6B, the drive motor 51 is driven in the reverse direction at a low speed to transmit the drive to the take-up shaft 13k and take up the sheet-like member 13m. While continuously performing the operation, the two conveying screws 13b1 and 13b2 were driven at a low rotational speed, and the developer G was slowly circulated in the reverse direction in the circulation path in the developing device 13.
On the other hand, in the operation of FIG. 6B, the drive motor 51 is repeatedly driven alternately in the reverse direction and the forward direction at a low speed rotation, so that the drive is transmitted to the winding shaft 13k or the drive transmission is canceled. Then, while intermittently performing the winding operation of the sheet-like member 13m, the two conveying screws 13b1 and 13b2 are alternately driven in the reverse direction and the forward direction at a low rotational speed, and the circulation path in the developing device 13 , The developer G can be slowly circulated in the reverse direction and the forward direction.
That is, in Modification 1, when the use of the developing device 13 is started in the image forming apparatus main body 1, the two conveying screws 13 b 1 and 13 b 2 (and the developing roller 13 a) are moved in the normal direction by the drive motor 51. The two rotations are carried by the drive motor 51 until the sheet-shaped member 13m is completely wound up by at least the winding shaft 13k after being driven to rotate for a predetermined time at a rotational speed smaller than the rotational speed (predetermined rotational speed). The screws 13b1 and 13b2 (and the developing roller 13a) are repeatedly driven to rotate alternately in the reverse direction and the forward direction at a rotational speed smaller than the normal rotational speed.
Even in such a case, the same effect as that of the present embodiment can be obtained. In particular, in Modification 1, when the sheet-like member 13m shown in FIG. 6B is wound, the developer G is continuously circulated in the opposite direction to the normal circulation direction by the conveying screws 13b1 and 13b2. However, since the circulation in the normal circulation direction is appropriately performed while the circulation in the reverse direction is performed, the winding time of the sheet-like member 13m is extra, but the toner supply port is separated from the circulation path in the collection path. The problem that the developer G flows to the position 13w and the developer G flows backward from the toner supply port 13w to the outside of the apparatus can be reduced.

<Modification 2>
FIG. 10 is a schematic cross-sectional view showing a new developing device 13 at the time of factory shipment as a second modification, and corresponds to FIG. 5 in the present embodiment.
As shown in FIG. 10, in the second modification, in the new developing device 13 (the developer G is preset in the closed space formed by the sheet-like member 13m), the winding shaft 13k is used. The other end side of the sheet-like member 13m is wound by one turn in the reverse direction (the reverse direction with respect to the winding direction of the winding shaft 13k and the clockwise direction in FIG. 10). Further, in order to ensure the sealing performance by the sheet-like member 13m, the vicinity of the other end side of the sheet-like member 13m is bonded (or thermally welded) to the flat portion 13r2 with a relatively light force.
With this configuration, when the driving motor 51 starts to be driven in the reverse direction as shown in FIG. 6B in the warming-up operation described above, the winding of the sheet-like member 13m is suddenly applied. The driving torque of the shaft 13k is not applied to the driving motor 51 together with the starting torque, but the driving torque of the winding shaft 13k applied with the tension of the sheet-like member 13m is delayed by one rotation described above from the timing at which the starting torque is applied. Since the drive motor 51 is applied, the maximum drive torque in the drive motor 51 can be reduced.

<Modification 3>
FIG. 11A is a schematic diagram showing a state in which the sheet-like member 13m is normally wound during the initial operation of the new developing device 13 as the third modification. On the other hand, FIG. 11B is a schematic diagram showing a state in which a winding failure of the sheet-like member 13m occurs during the initial operation of the new developing device 13 as the third modification.
As shown in FIG. 11, in the third modification, a sheet detection sensor 42 as a detection unit is installed in the developing case 13r (in the vicinity of the opening 13r1). The sheet detection sensor 42 detects a state in which the sheet-like member 13m is not present inside the developing device 13, and is used as a detection unit that detects a state in which the winding of the sheet-like member 13m is completed. This function functions in place of the density detection sensor 40. As the sheet detection sensor 42, a known reflection type photosensor including a light emitting element and a light receiving element can be used. Further, as the sheet-like member 13m, it is preferable to use a sheet-shaped member made of a material that reflects light so that the sheet detection sensor 42 can optically detect whether or not the sheet-like member 13m is present at that position. .
Then, in the warming-up operation described above, as shown in FIG. 6B, the drive motor 51 is driven in the reverse direction for a predetermined time, and whether or not the sheet-like member 13m is at that position by the sheet detection sensor 42. Is detected.
When the sheet detection sensor 42 detects that there is no sheet-like member 13m, as shown in FIG. 11A, the sheet-like member 13m is normally wound around the winding shaft 13k, and the developing device 13 Assuming that the sheet-like member 13m does not remain therein, a normal image forming process (developing step) is performed as it is. On the other hand, when the sheet detection sensor 42 detects that the sheet-like member 13m is present, the sheet-like member 13m is normally wound around the take-up shaft 13k as shown in FIG. Assuming that the sheet-like member 13m remains in the developing device 13, the operation of the developing device 13 (image forming device 1) is interrupted without performing the normal image forming process (developing step) as it is. (Stop driving).

As described above, in the present embodiment, when the sheet-like member 13m forming the closed space in which the developer G is accommodated inside the developing device 13 is used in the image forming apparatus main body 1. Is provided with a winding shaft 13k that rotates in a predetermined direction and winds the sheet-like member 13m with the direction intersecting the width direction of the sheet-like member 13m as a winding direction, and drives the winding shaft 13k. Drive transmission mechanisms 13g, 13h, 13p, and 13q that are rotated in a predetermined direction by a motor 51 (driving means) are provided. The drive transmission mechanisms 13g, 13h, 13p, and 13q are configured to stop the rotation of the take-up shaft 13k by interrupting the drive transmission from the drive motor 51 after the winding of the sheet-like member 13m is completed. Yes. Further, a density detection sensor 40 (detection means) that detects a state in which the winding of the sheet-like member 13m is completed is installed.
As a result, it is possible to reduce the problem that the use of the developing device 13 is started in the state as it is without the sheet member 13m being normally wound around the winding shaft 13k.

In the present embodiment, the second conveying screw 13b2 that functions as a recovery screw is installed above the first conveying screw 13b1 that functions as a supply screw, and the doctor blade 13c is installed below the developing roller 13a. The present invention is applied to the developing device 13 of the component developing system. However, the form of the developing device to which the present invention is applied is not limited to this. For example, a second conveying screw that functions as a recovery screw is installed below the first conveying screw that functions as a supply screw, and is a doctor blade. Is a two-component development type developing device installed above the developing roller, a two-component development type developing device in which a plurality of conveying members are arranged in parallel in the horizontal direction, or a toner containing no carrier as a developer. The present invention can also be applied to a single-component developing type developing apparatus.
Even in such a case, the same effect as that of the present embodiment can be obtained.

In the present embodiment, the present invention is applied to the image forming apparatus 1 in which the developing device 13 is configured as a unit that is detachably attached to the main body of the image forming apparatus. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to an image forming apparatus in which a part or all of the image forming unit is formed as a process cartridge. In that case, the workability of maintenance of the image forming unit is improved.
In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing unit (developing device) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. It is defined as a unit in which at least one of the cleaning units and the image carrier are integrated and installed detachably with respect to the image forming apparatus main body.

Further, in the present embodiment, by providing the take-up shaft 13k with the feed screw portion 13q, the take-up shaft 13k is moved in the axial direction to the position where the gears 13f and 13g are disengaged, and the drive force from the drive means It was configured to be able to shut off. On the other hand, without providing the feed screw portion 13q, the driving side gear 13f and the driven side gear 13g are respectively helical gears, and the driven side gear 13g installed on the winding shaft 13k is engaged with the driving side gear 13f. By receiving the component force that moves in the axial direction, the winding shaft 13k can be moved in the axial direction to the position where the gears 13f and 13g are disengaged, and the driving force from the driving means can be cut off. it can.
Even in such a case, the same effect as that of the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus (image forming apparatus main body),
11, 11Y, 11C, 11M, 11BK Photosensitive drum (image carrier),
13 Developing device (developing part),
13a Development roller (developer carrier),
13b1 first conveying screw (conveying member),
13b2 second conveying screw (conveying member),
13c Doctor blade (developer regulating member),
13d partition part,
13e first gear,
13f 2nd gear (drive side gear),
13g 3rd gear (driven gear, drive transmission mechanism),
13h one-way clutch (drive transmission mechanism),
13k winding shaft,
13m sheet-like member,
13n sealing material,
13p female thread (drive transmission mechanism),
13q feed screw (drive transmission mechanism),
13r development case,
13r1 opening,
13r2 plane part,
40 Concentration detection sensor (detection means),
41 Torque detection sensor (detection means),
42 Sheet detection sensor (detection means),
G developer (two-component developer), T toner, C carrier.

JP-A-2006-1254 JP 2014-81665 A JP 2012-159602 A

Claims (10)

A developing device that is detachably installed on the image forming apparatus main body, contains a developer therein, and develops a latent image formed on the surface of the image carrier,
A sheet-like member that isolates the interior so as to form a closed space in which the developer is accommodated in the developing device so that the developer accommodated in the developing device does not leak to the outside;
A winding shaft that rotates in a predetermined direction so that the sheet-shaped member is removed from the inside of the developing device and winds the sheet-shaped member with a direction intersecting the width direction of the sheet-shaped member as a winding direction;
Drive is transmitted from the drive means, the winding shaft is rotated in the predetermined direction to wind up the sheet-like member, and the drive transmission from the drive means is cut off after the winding of the sheet-like member is completed. A drive transmission mechanism for stopping the rotation of the winding shaft;
Detecting means for detecting a state where winding of the sheet-like member is completed;
A developing device comprising:   When the image forming apparatus main body starts to be used, the driving unit rotates the winding shaft, and when the detection unit detects that the sheet-shaped member has been completely wound, the use is performed. 2. The developing device according to claim 1, wherein when the state of winding of the sheet-like member is not detected by the detection unit, the start of use is interrupted.   3. The development according to claim 2, wherein when the state of winding of the sheet-like member is not detected by the detecting unit, the fact that winding of the sheet-like member is not completed is notified. apparatus.   The procedure for completing the winding of the sheet-like member is displayed on the display unit when the detection unit does not detect the completion of the winding of the sheet-like member. Development device.   The detection unit is a density detection sensor that detects a state in which an image density of a toner image formed on the image carrier by the developing device has reached a predetermined threshold value. Item 5. The developing device according to Item 4.   The developing device according to claim 1, wherein the detection unit is a sheet detection sensor that detects a state where the sheet-like member is not present in the developing device.   The developing device according to claim 1, wherein the detection unit is a torque detection sensor that detects a state in which a change in driving torque of the driving unit is greater than a predetermined value. . A plurality of conveying members that are installed inside the developing device and are circulated and conveyed by a predetermined rotational speed in the forward direction by the driving means during the developing process to circulate and convey the developer contained in the developing device. With
The drive transmission mechanism causes the take-up shaft to idle when the plurality of conveying members are rotated in the forward direction by the driving unit, and the plurality of conveying members are moved with respect to the positive direction by the driving unit. It is configured to rotate the winding shaft in the predetermined direction when driven to rotate in the reverse direction,
When the use is started in the image forming apparatus main body, the plurality of conveying members are rotationally driven in the reverse direction by the driving unit, and the sheet-like member is wound by the winding shaft. The developing device according to claim 1, wherein the developing device is characterized in that: A process cartridge that is detachably attached to the image forming apparatus main body,
9. A process cartridge in which the developing device according to claim 1 and the image carrier are integrated.   An image forming apparatus comprising the developing device according to claim 1.

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