JP2016148826A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that prevents the occurrence of a failure in take-up of a sheet-like member even when taking up the sheet-like member in a direction intersecting with the width direction, a process cartridge, and an image forming apparatus.SOLUTION: A developing device includes a take-up shaft 13k that rotates in a predetermined direction to take up a sheet-like member 13m that has formed a closed space accommodating developer G inside a developing device 13, in a take-up direction that is a direction intersecting with the width direction of the sheet-like member 13m, so that the sheet-like member 13m is removed when the developing device is started to be used in an image forming apparatus body 1. A take-up path in the take-up direction where the sheet-like member 13m is taken up by the take-up shaft 13k is formed to be longer at the center part in the width direction than at both ends in the width direction.SELECTED DRAWING: Figure 5

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 (seal member, sealing sheet) that separates a space containing a developer as a closed space is detachable (see, for example, Patent Documents 1 and 2).

Specifically, a closed space in which the developer is accommodated is formed in the developing device that is attached to the main body of the image forming apparatus and is not yet used so that the developer that is accommodated in advance does not leak to the outside. Thus, a sheet-like member that isolates the interior is provided.
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 agitated and mixed by a conveying member such as a conveying screw. 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 Document 2, a winding shaft for winding a sheet-like member (sealing sheet) is provided, and the winding shaft is driven to rotate by a motor so that the sheet-like member is substantially orthogonal to the width direction. A technique for automatically winding in the direction of movement is disclosed.

In the conventional technique described above, the sheet-like member is wound up (removed) in a direction substantially orthogonal to the width direction, so that the sheet-like member is wound up in the width direction. An opening for removing the shaped member from the inside of the developing device can be formed on the ceiling surface side of the developing case that is not buried in the developer, and an effect of reducing the problem that the developer leaks from the opening can be expected. .
However, in the conventional technology, when the sheet-like member is wound in a direction substantially orthogonal to the width direction, the sheet is wound so that the center portion in the width direction precedes both ends in the width direction. In some cases, the sheet-like member is wrinkled or broken, resulting in poor winding.

  The present invention has been made to solve the above-described problems, and even when the sheet-like member is wound in a direction intersecting (orthogonal) with respect to the width direction, the sheet-like member is poorly wound. It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus that are less likely to cause image formation.

  According to the first aspect of the present invention, the developing device is detachably installed on the main body of the image forming apparatus, the developer is accommodated therein, and the latent image formed on the surface of the image carrier is displayed. A developing device for developing, wherein the developer is contained in the developing device so that the developer contained in the developing device does not leak to the outside until use in the image forming apparatus main body is started. A sheet-like member that isolates the interior so that a closed space is formed, and a predetermined direction so that the sheet-like member is removed from the inside of the developing device when use is started in the image forming apparatus main body. A winding shaft that winds the sheet-like member around a direction that intersects the width direction of the sheet-like member and winds up the sheet-like member by the winding shaft. Winding path direction is one that is formed such that the widthwise central portion is longer than the width direction end portions.

  According to the present invention, a developing device, a process cartridge, and an image forming apparatus that are unlikely to cause poor winding of a sheet-like member even when the sheet-like member is wound in a direction intersecting the width direction. 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. 2A is a schematic cross-sectional view showing a new developing device at the time of factory shipment, and FIG. 2B is a schematic cross-sectional view showing a state in which the 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 a figure which shows a winding shaft in the width direction. In the developing device as the modified example 1, (A1) a schematic view showing a state in which the sheet-like member is wound up in the central portion in the width direction, (A2) an enlarged view showing the main part in the central portion in the width direction, and (B1) It is the schematic which shows the state by which a sheet-like member is wound up by the width direction both ends, (B2) The enlarged view which shows the principal part of the width direction both ends. In the developing device as the modified example 2, (A) a schematic diagram showing a state in which a sheet-like member is wound, and (B) a schematic diagram showing a state during normal image formation. FIG. 10 is a schematic diagram showing a main part of four developing devices as a third modification.

Embodiment.
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 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 a writing unit (not shown). 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 a cyan component electrostatic latent image. 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. At the position of the primary transfer bias roller 14, the toner images of the respective colors formed on the photosensitive drums 11Y, 11M, 11C, and 11BK are sequentially superimposed and transferred onto the intermediate transfer belt 17 (1). Next 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 photoconductor drums 11Y, 11M, 11C, and 11BK pass through a charge removal unit (not shown), and a series of image forming processes on the photoconductor 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 an intermediate transfer belt cleaning unit (not shown). 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 as viewed in the longitudinal direction.
Since each image forming unit has almost the same structure, the image forming unit and the developing device are illustrated in FIG. 2 to FIG. 4 except for alphabets (Y, C, M, BK).

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 counterclockwise by a drive motor (not shown).

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, toner conveyance (not shown) is performed based on information on the toner density (the ratio of toner in the developer G) detected by a magnetic sensor (not shown) installed in the developing device 13. The toner T is appropriately supplied from the toner supply port 13e from the toner container 28 into the developing device 13 through the tube.
The supply of the toner T is not limited to the toner density information, but may be performed based on the image density information detected from the reflectance of the toner image formed on the photosensitive belt or the intermediate transfer belt. Good. 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 conveying members, a doctor blade 13c as a developer regulating member, Etc.
The developing roller 13a as the developer carrying member is a sleeve 13a2 formed of a non-magnetic material such as aluminum, stainless steel, brass, or conductive resin in a cylindrical shape by a driving motor (not shown) as a driving means. It is configured to rotate counterclockwise. 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 (conveying members) stir and mix the developer G accommodated in the developing device 13 while circulating in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 2).
The first transport screw 13b1 (supply transport member) is disposed at a position facing the developing roller 13a, and transports the developer G horizontally in the longitudinal direction (rotational axis direction) (see FIG. 3B). At the same time, the developer G is supplied onto the developing roller 13a at the position of the pumping magnetic pole (the supply in the direction of the white arrow in FIG. 3B). The first transport screw 13b1 rotates counterclockwise in FIG.

The second conveying screw 13b2 (collecting conveying member) as a rotating member is disposed above the first conveying 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 opposite to the rotation direction of the developing roller 13a (clockwise in FIG. 2).
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 13f to the upstream side of the transport path by the first transport screw 13b1. It conveys via the relay part 13g (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 conveying screws 13b1 and 13b2 together with the developing roller 13a form a drive system by a gear train, and are configured to be rotationally driven by a drive motor as drive means. That is, when the drive motor is driven and controlled by the control unit, the two conveying screws 13b1 and 13b2 are rotationally driven together with the developing roller 13a.
Although not shown in detail, the developing roller 13a receives a driving force from a driving motor on a 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 direct transmission coupling is provided. Further, 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 the gear installed on the shaft portion on one end side in the width direction of the first conveying screw 13b1 via an idler. doing. 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. 6 and 7). 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, a driving motor (driving means) for driving the developing device is provided independently as a developing driving motor separately from the driving motor for rotationally driving the photosensitive drum 11 and the like.

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).
3 and 4, 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 2 It communicates via the relay part 13g. 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 13g and reaches the upstream side of the supply conveyance path.
3 and 4, 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 communicate with each other via the first relay unit 13f. Yes. Then, the developer G that has not been supplied onto the developing roller 13a through the supply conveyance path by the first conveyance screw 13b1 stays in the vicinity of the first relay portion 13f and rises up, and then passes through the first relay portion 13f. 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 portion 13f (the developer is transferred from the supply transport path to the collection transport path in the direction of gravity), the first transport screw 13b1 A paddle-shaped portion or a screw portion in which the winding direction of the screw is formed in the reverse direction can be provided at a downstream position (a position corresponding to the first relay portion 13f).

  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 line arrow in FIGS. 3 and 4. 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.

Although illustration is omitted, 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 13e (located in the vicinity of the first relay portion 13f). New toner T is supplied.
3 and 4, the toner replenishing port 13e is located above the upstream side of the transport path by the second transport screw 13b2 and away from the developing area (the range in the longitudinal direction of the developing roller 13a). It is arranged outside.). By installing the toner replenishing port 13e in the vicinity of the first relay portion 13f in this way, the developer that has separated from the developing roller 13a falls from above the replenishment toner having a small specific gravity in the collecting transport path, and the collecting transport 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 13e is disposed in the collection transport path by the second transport screw 13b2, but the position of the toner replenishing port 13e 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. 5B) so that the sheet-like member 13m is removed from the inside of the developing device 13 when use in the image forming apparatus main body 1 is started. 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. 5B). ) 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, the new developing device 13 (including recycled products) 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. 5A, in the present embodiment, the sheet-like member 13m includes, in the developing device 13, the tip of the partition portion 13d, the tip of the doctor blade 13c, and the partition portion 13d. The end of the sheet-like member 13m on the doctor blade 13c side is passed between the end of the developing roller extending over a virtual plane (a straight line in the drawing) connecting the tip of the doctor blade 13c and the tip of the doctor blade 13c. Is bonded to the outside of the developing device 13 with a relatively light force (or heat-welded), and the other end of the sheet-like member 13m is wound around the take-up shaft 13k to give tension to the sheet-like member 13m. . Thereby, the developer is prevented from leaking out from the first conveying screw 13b1 (supply screw) side. Similarly, the sheet-like member 13m has a longitudinal length exceeding a virtual plane (in the drawing, a straight line) connecting the tip of the partition portion 13d, the winding shaft 13k, and the tip of the partition portion 13d and the winding shaft 13k. The developer is prevented from leaking out from the second conveying screw 13b2 (collection screw) side by the tension (tension) of the sheet-like member 13m. If the tip of the partition portion 13d and the tip of the doctor blade 13c are bonded (or thermally welded) with a relatively light force, the sealing performance is further increased.

Further, referring to FIG. 5 (or FIG. 6, FIG. 7) and the like, 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.

As shown in FIG. 5 (A), the developing device 13 configured in this way is shown in FIG. 5 (B) while the developer G accommodated therein is sealed and enclosed by the sheet-like member 13m. As shown, it is attached to the image forming apparatus 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. 5B, the image forming operation (developing step) 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. In the present embodiment, the take-up shaft 13k is formed in a crown shape (a drum shape) as shown in FIG. 8, which will be described in detail later.
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 the present embodiment, even when the developing device 13 is transported alone as a replacement, the developing device 13 is transported in a state of being mounted on the image forming apparatus main body 1 at the time of shipment. Even in this case, since the developer G stored in advance in the developing device 13 is sealed by the sheet-like member 13m, the developer G stored in the interior due to vibration generated during transportation or the like. Can be prevented from leaking outside the developing device 13.

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 the 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 (see FIG. 2). it can).
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, in the developing device 13 according to the present embodiment, the winding path in the winding direction in which the sheet-like member 13m is wound by the winding shaft 13k is longer in the center in the width direction than in the both ends in the width direction. Is formed. In other words, the length of the winding path at the central portion in the width direction of the sheet-like member 13m wound by the winding shaft 13k is equal to the winding path at both ends in the width direction of the sheet-like member 13m wound by the winding shaft 13k. It is formed to be longer than the length of.
Specifically, the take-up shaft 13k is formed in a crown shape (a drum shape) as shown in FIG. That is, the winding shaft 13k is formed so that the outer diameter D1 of the width direction center portion is larger than the outer diameter D2 of the width direction center portion (D1> D2). In other words, the take-up shaft 13k is formed so that the outer diameter gradually increases from the center in the width direction to the center in the width direction. In the present embodiment, the drum amount ((D1-D2) / 2) of the winding shaft 13k is set to be about 0.1 to 1 mm.
In addition, as the winding shaft 13k, as shown in FIG. 8 (A), it is possible to use one formed so that the ridge line of the outer peripheral surface is curved, as shown in FIG. 8 (B), What formed so that the ridgeline of an outer peripheral surface may become linear form can also be used.

Thus, by forming the winding shaft 13k in a crown shape, the circumferential length (πD1) of the central portion in the width direction of the winding shaft 13k becomes longer than the circumferential length (πD2) of the central portion in the width direction. As the take-up shaft 13k rotates, the sheet-like member 13m is wound around the take-up shaft 13k with both end portions in the width direction preceding the center portion in the width direction. In other words, the length of the winding path at the center in the width direction of the sheet-like member 13m wound by the winding shaft 13k is equal to the winding path at both ends in the width direction of the sheet-like member 13m wound by the winding shaft 13k. Longer than the length of.
Therefore, the sheet-like member 13m is wound around the take-up member 13k so that the widthwise central portion is pulled to both ends in the width direction, so that the sheet-like member 13m is wrinkled or broken and wound up. It becomes difficult to produce the malfunction which a defect generate | occur | produces.

In the present embodiment, the winding shaft 13k is rotated in a predetermined direction (counterclockwise in FIG. 5B) when a driving force is transmitted from a driving motor (driving means) that drives the developing device 13. Then, after a predetermined time which is equal to or longer than the time for completing the winding of the sheet-like member 13m, the transmission of the driving force from the driving motor (driving means) is cut off and the rotation is stopped. Here, the above-mentioned “predetermined time” is within the warm-up operation time until the developing device 13 is mounted on the image forming apparatus main body 1 and the developing process is performed. That is, when a new developing device 13 is mounted on the image forming apparatus 1 (or when the new image forming apparatus 1 with the new developing device 13 mounted is started), the image forming condition is satisfied. During the warming-up operation in which adjustment or the like is performed, the rotation driving of the winding shaft 13k is started by the drive motor from the state of FIG. 5B, and the winding operation of the sheet-like member 13m is performed. Then, after the winding of the sheet-like member 13m is completed (after the state shown in FIG. 2), the drive transmission from the drive motor to the winding shaft 13k is cut off and the winding shaft 13k (the sheet-like member 13m is wound). The normal image forming operation (development process) is performed in a state where the rotation is stopped.
Further, when the sheet-like member 13m is wound, the developing roller 13a conveying screws 13b1 and 13b2 are also driven, and the developing roller 13a having unevenness on the surface vibrates the sheet-like member 13m, so that it adheres on the sheet-like member 13m. The developed developer is removed. Furthermore, the tip of the partition part 13d and the opening 13r1 passing through the sheet-like member 13m respectively scrape off the developer attached to the surface of the sheet-like member 13m.

  In this way, by stopping the rotation of the winding shaft 13k after the winding of the sheet-like member 13m is completed, the winding shaft 13k is permanently driven in conjunction with the driving of the developing device 13, thereby causing an abnormality. It is possible to suppress a problem that a sound is generated or a state in which the driving torque is always 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.

With reference to FIGS. 6 and 7, the mechanism for interrupting transmission of the driving force from the driving motor (driving means) to the winding shaft 13k after a predetermined time has elapsed as described above will be described in detail.
As described above, the developing device 13 is provided with the second conveying screw 13b2 as a rotating member that rotates when a driving force is transmitted from a driving motor (driving means) for the developing device 13 via a gear train. ing. The take-up shaft 13k is provided with a third gear 13g as a driven side gear that meshes with a second gear 13f as a drive side gear provided on the second transport screw 13b2 (rotating member). 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. 6 and 7 and the width direction), and after a predetermined time has elapsed, the second gear 13f and the third gear 13g are engaged. 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.
With this configuration, the developing roller 13a and the conveying screws 13b1 and 13b2 can be used by using the driving force of the driving motor that drives the developing device 13 without independently providing a motor for driving the winding shaft 13k. It is possible to cut off only the drive of the winding shaft 13k without shutting off the drive of. 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.

In the present embodiment, the length of the winding path in the central portion in the width direction of the sheet-like member 13m wound by the winding shaft 13k is determined by forming the winding shaft 13k in a crown shape. It formed so that it might become longer than the length of the winding path | route of the width direction both ends in the sheet-like member 13m wound up by 13k.
On the other hand, as shown in FIGS. 9A1 and 9A2, in the sheet-like member 13m wound by the winding shaft 13k, the protrusion 13r3 is provided in the winding path in the central portion in the width direction. The length of the winding path at the center in the width direction can be formed to be longer than the length of the winding path at both ends in the width direction of the sheet-like member 13m wound by the winding shaft 13k.
Specifically, as shown in FIG. 9, a flat portion 13r2 (upper part is covered with a cover member) formed in a part of the developing case 13r is wound in the winding direction in which the sheet-like member 13m is wound. It is configured to function as a part of the take route. That is, the winding path is formed such that a part (the flat surface portion 13r2) thereof is along the developing case 13r. The developing case 13r is formed with a protrusion 13r3 protruding in a direction (upward) away from the developing case 13r (ceiling) at a portion corresponding to the winding path in the central portion in the width direction. That is, as shown in FIGS. 9A1 and 9A2, the winding path (plane portion 13r2) in the central portion in the width direction is formed with a protruding portion 13r3 that rises upward. As shown in B1) and (B2), such a protruding portion 13r3 is not formed in the winding path (plane portion 13r2) at both ends in the width direction (the portion other than the central portion in the width direction). . In addition, it is preferable that the part of projection part 13r3 which the sheet-like member 13m contacts is a curved surface shape so that the sheet-like member 13m may not be damaged, and it is a spherical shape or the shape where D cut extends in a longitudinal direction.

Even in such a case, the sheet-like member 13m is wound around the winding shaft 13k with both ends in the width direction leading to the center portion in the width direction by rotating the winding shaft 13k. Become. In other words, the length of the winding path at the center in the width direction of the sheet-like member 13m wound by the winding shaft 13k is equal to the winding path at both ends in the width direction of the sheet-like member 13m wound by the winding shaft 13k. Longer than the length of.
Therefore, the sheet-like member 13m is wound around the take-up member 13k so that the widthwise central portion is pulled to both ends in the width direction, so that the sheet-like member 13m is wrinkled or broken and wound up. It becomes difficult to produce the malfunction which a defect generate | occur | produces.
In order to further reliably form such a difference in the length of the winding path, it is preferable to provide a guide portion 13r4 (cover member) so as to sandwich the sheet-like member 13m between the flat portion 13r2. .

In the present embodiment, the rotation directions of the rotating members 13a, 13b1, 13b2 to which the developing device 13 is driven during normal image formation and the rotations at which the developing device 13 is driven when the winding shaft 13k is driven to rotate. The rotation directions of the members 13a, 13b1, and 13b2 are configured in the same direction.
On the other hand, as shown in FIG. 10, the rotation direction of each rotation member 13a, 13b1, 13b2 that drives the developing device 13 during normal image formation (refer to the arrow direction in FIG. 10B). The rotation direction of each of the rotating members 13a, 13b1, 13b2 that drives the developing device 13 when the winding shaft 13k is driven to rotate (refer to the arrow direction in FIG. 10A) is opposite. It can also be configured.
Specifically, a drive motor (development drive motor) that can rotate in both forward and reverse directions is used as a drive motor (development drive motor) that drives the developing device 13. When the third gear 13g rotates in the forward direction (counterclockwise in FIG. 10), the inner diameter portion of the third gear 13g (see FIGS. 6 and 7) can be moved to the winding shaft 13k. A one-way clutch that does not transmit rotation to the take-up shaft 13k when the third gear 13g rotates in the reverse direction (clockwise in FIG. 10) is transmitted.

With such a configuration, as shown in FIG. 10A, when the sheet-like member 13m is taken up by the take-up shaft 13k at the start of use of the new developing device 13, the developing device 13 is reversely rotated by the drive motor. Then, the rotation of the third gear 13g in the forward direction causes rotation to be transmitted to the take-up shaft 13k via the one-way clutch (the take-up shaft 13k rotates and the sheet-like member 13m is taken up). ). On the other hand, during normal image formation, the developing device 13 is rotated forward by the drive motor and the third gear 13g is rotated in the reverse direction, so that the rotation is not transmitted to the take-up shaft 13k by the one-way clutch. (The third gear 13g idles and the winding shaft 13k stops rotating).
Even in this case, only the driving of the winding shaft 13k is performed without interrupting the driving of the developing roller 13a and the conveying screws 13b1 and 13b2 by using the driving force of the driving motor that drives the developing device 13. Can be cut off. Therefore, the developing device 13 can be reduced in size and weight. Further, as shown in FIG. 10 (A), the sheet-like member 13m is wound up along the rotation direction of the developing roller 13a rotating in the reverse direction, so that the winding property of the sheet-like member 13m is improved. .
Note that the mechanism using the one-way clutch described here and the mechanism (the third gear 13g and the winding shaft 13k) of the feed screw portion 13q and the female screw portion 13p described earlier with reference to FIGS. And a mechanism that slides in the axial direction).

Referring to FIG. 11, in the present embodiment, a plurality of developing devices 13 installed to face the photosensitive drums 11Y, 11M, 11C, and 11BK of the respective colors (yellow, cyan, magenta, and black). (Y), 13 (M), 13 (C), and 13 (BK) can also be configured to be driven by one drive motor 40 (drive means). In such a case, when the image forming apparatus 1 arrives, sheet-like members respectively installed in the four developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK). Since 13m is driven by one drive motor 40 and simultaneously wound on each winding shaft 13k, there is a possibility that a large load (drive torque) may be generated in the drive motor 40 as it is. . Therefore, in the example of FIG. 11, in such a case, a large load (drive torque) is not generated at a stretch in the drive motor 40, so that the drive motor 40 does not increase in size and the drive motor 40 malfunctions. Is prevented from occurring.
Here, in FIG. 11, the path through which the driving force is transmitted from the driving motor 40 to the take-up shaft 13k is illustrated in a simplified manner, but the developing devices 13 (Y), 13 (M), 13 (C ), 13 (BK), the drive mechanism described above with reference to FIGS. 6 and 7 is employed.

Specifically, the drive motor 40 (drive means) is separate from the developing device (for example, the developing device 13 (Y) for yellow) as a separate developing device 13 (installed in the image forming apparatus main body 1). M), 13 (C), and 13 (BK) are also driven, and in other developing devices 13 (M), 13 (C), and 13 (BK) configured similarly to the developing device 13 (Y). The driving force is transmitted also to the winding shaft 13k and rotated in a predetermined direction.
Then, driving force to the winding shaft 13k of the developing device 13 (Y) and the winding shaft 13k of another developing device 13 (M), 13 (C), 13 (BK) by the driving motor 40 (driving means). The timing at which the driving torque generated when the sheet-like member 13m is wound around the winding shaft 13k of the developing device 13 (Y) is maximized after the start of the transmission of the developing device 13 (Y) is different from the other developing devices 13 (M), 13 (C) and (BK) are configured so as not to overlap with the timing at which the driving torque generated by winding the sheet-like member 13m on the winding shafts 13k of 13 (BK) becomes maximum. That is, the driving torque when the sheet-like member 13m is wound around the winding shaft 13k of the four developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK) by one driving motor 40. The peaks are configured to occur at different times. In other words, the driving torque peak when the sheet-like member 13m is wound around the winding shaft 13k of the developing device 13 (Y) for yellow and the winding shaft 13k of the developing device 13 (M) for magenta. The peak of driving torque when the sheet-like member 13m is wound, the peak of driving torque when the sheet-like member 13m is wound around the winding shaft 13k of the cyan developing device 13 (C), and the black The peak of the driving torque when the sheet-like member 13m is wound around the winding shaft 13k of the developing device 13 (BK) is configured not to overlap with each other at the same time. Here, the timing at which the driving torque becomes maximum on the winding shaft 13k (peak of driving torque) is the moment when the maximum tension is generated in the sheet-like member 13m, and the sheet adhered to the housing of the developing device 13 This is the moment when the shaped member 13m is pulled by the winding shaft 13k and peeled off from the housing.

Specifically, in the example of FIG. 11A, the developing is performed separately from the winding shaft 13k of the developing device (for example, the developing device 13 (Y) for yellow is used as a reference) by the driving motor 40 (driving means). In a state before transmission of driving force to the winding shaft 13k of the devices 13 (M), 13 (C), 13 (BK) is started, the sheet shape with respect to the winding shaft 13k of the developing device 13 (Y). The amount of slack of the member 13m is configured to be different from the amount of slack of the sheet-like member 13m with respect to the take-up shaft 13k of another developing device 13 (M), 13 (C), 13 (BK). As shown in FIG. 11A, the new yellow developing device 13 (Y) is configured so that the amount of looseness of the sheet-like member 13m with respect to the take-up shaft 13k is small. On the other hand, in each of the new developing devices 13 (M), 13 (C), and 13 (BK), the sheet-like member 13 m is wound by a predetermined amount in the reverse rotation direction of the winding shaft 13 k in advance. Thus, the portion is configured to be a slack portion 13m1 of the sheet-like member 13m with respect to the winding shaft 13k. The length of the slack portion 13m1 is different for each of the developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK).
With such a configuration, the driving motor 40 is driven to wind the sheet-like member 13m around the winding shaft 13k in the four developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK). Is started, the timing at which the driving torque becomes maximum on each winding shaft 13k (the peak of the driving torque) is shifted. Specifically, the developing device 13 (Y) for yellow, the developing device 13 (M) for magenta, the developing device 13 (C) for cyan, and the developing device 13 (BK) for black are selected from those having a small amount of slack. In this order, the timing is shifted and a peak of driving torque occurs.

In the example of FIG. 11B, the winding shaft 13k of the developing device (for example, the developing device 13 for yellow (Y) is used as a reference) has an outer diameter d1 of another developing device 13 ( The outer diameters d2 to d4 of the winding shafts 13k of M), 13 (C), and 13 (BK) are different. That is, the outer diameter d1 of the winding shaft 13k of the yellow developing device 13 (Y), the outer diameter d2 of the winding shaft 13k of the magenta developing device 13 (M), and the cyan developing device 13 (C ) And the outer diameter d4 of the winding shaft 13k of the black developing device 13 (BK) are different from each other (in the example of FIG. 11B). D4 <d1 <d2 <d3).
With such a configuration, the driving motor 40 is driven to wind the sheet-like member 13m around the winding shaft 13k in the four developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK). Since the speed at which the sheet-like member 13m is taken up by the respective take-up shafts 13k is different when the start is started, the timing at which the drive torque reaches the maximum at each take-up shaft 13k (the peak of the drive torque) It will shift. Specifically, a developing device 13 (BK) for black, a developing device 13 (Y) for yellow, a developing device 13 (M) for magenta, and a developing device 13 (C) for cyan from those having a small outer diameter. In this order, the timing is shifted and a peak of driving torque occurs.
In the example of FIG. 11B, when the winding shaft 13k is formed in a crown shape as shown in FIG. 8, the outer diameters d1 to d4 of the winding shaft 13k are the outer diameters of the respective parts. It becomes. For example, when the outer diameter d1 of the take-up shaft 13k of the yellow developing device 13 (Y) is smaller than the outer diameter d2 of the take-up shaft 13k of the magenta developing device 13 (M), the widthwise center from the both ends in the width direction. Such a magnitude relationship is established over the part. That is, the outer diameter d1 (D2) of the winding shaft 13k of the yellow developing device 13 (Y) is larger than the outer diameter d2 (D2) of the winding shaft 13k of the magenta developing device 13 (M) at both ends in the width direction. The outer diameter d1 (D1) of the take-up shaft 13k of the yellow developing device 13 (Y) is smaller than the outer diameter d2 (D1) of the take-up shaft 13k of the magenta developing device 13 (M). Get smaller.

  Here, in the example of FIG. 11, the four developing devices 13 (Y), 13 (M), 13 (C), and 13 (BK) are configured to be driven by a single drive motor 40. The number of developing devices 13 driven by a motor is not limited to this. For example, three color developing devices 13 (Y), 13 (M), and 13 (C) are driven by one color driving motor, and the black developing device 13 is driven by one black driving motor. It can also be configured to drive only (BK). In the drive system that drives the plurality of developing devices 13 by one drive motor, the same configuration as that of the example of FIG. 11 can be adopted.

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. The winding path in the winding direction in which the member 13m is wound is formed so that the center part in the width direction is longer than both ends in the width direction.
Thereby, even if it is a case where the sheet-like member 13m is wound in the direction which cross | intersects with respect to the width direction, it can be made hard to generate | occur | produce the winding-up defect of the sheet-like member 13m.

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.
In the present embodiment, the take-up shaft 13k is automatically rotated by the driving means. However, the take-up shaft 13k may be manually rotated.
And even if it is such a case, the effect similar to the thing of this Embodiment can be acquired.

  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,
13b2 second conveying screw (rotating member),
13c Doctor blade (developer regulating member),
13d partition part,
13e first gear,
13f 2nd gear (drive side gear),
13g 3rd gear (driven gear),
13k winding shaft,
13m sheet-like member,
13n sealing material,
13p female thread,
13q feed screw,
13r development case,
13r1 opening,
13r2 plane part,
13r3 protrusion,
13r4 guide part,
G developer (two-component developer), T toner, C carrier.

Japanese Patent No. 5397616 JP 2014-81665 A

Claims (13)

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 closed space in which the developer is accommodated is formed in the developing device so that the developer accommodated in the developing device does not leak to the outside until use in the image forming apparatus main body is started. A sheet-like member that isolates the interior,
The winding direction is a direction that rotates in a predetermined direction and intersects the width direction of the sheet-like member so that the sheet-like member is removed from the inside of the developing device when use is started in the image forming apparatus main body. A winding shaft for winding the sheet-like member as
With
The developing device, wherein a winding path in a winding direction in which the sheet-like member is wound by the winding shaft is formed so that a central portion in the width direction is longer than both end portions in the width direction.   The developing device according to claim 1, wherein the winding shaft is formed in a crown shape. The winding shaft is installed outside the interior in which the developer is accommodated in the developing device,
The winding path is formed so that a part thereof is along the developing case,
3. The developing case according to claim 1, wherein a protrusion that protrudes in a direction away from the developing case is formed at a portion corresponding to the winding path in a central portion in the width direction. Development device. The winding shaft is rotated in the predetermined direction when a driving force is transmitted from a driving unit that drives the developing device,
The driving means also drives another developing device installed in the image forming apparatus main body separately from the developing device, with respect to a winding shaft in the other developing device configured similarly to the developing device. Even if you transmit the driving force and rotate it in a predetermined direction,
The winding shaft of the developing device is formed so that an outer diameter thereof is different from an outer diameter of a winding shaft of the another developing device. The developing device according to 1. 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 closed space in which the developer is accommodated is formed in the developing device so that the developer accommodated in the developing device does not leak to the outside until use in the image forming apparatus main body is started. A sheet-like member that isolates the interior,
The winding direction is a direction that rotates in a predetermined direction and intersects the width direction of the sheet-like member so that the sheet-like member is removed from the inside of the developing device when use is started in the image forming apparatus main body. A winding shaft for winding the sheet-like member as
With
The winding shaft is rotated in the predetermined direction when a driving force is transmitted from a driving unit that drives the developing device,
The driving means also drives another developing device installed in the image forming apparatus main body separately from the developing device, with respect to a winding shaft in the other developing device configured similarly to the developing device. Even if you transmit the driving force and rotate it in a predetermined direction,
After the driving means starts transmission of driving force to the winding shaft of the developing device and the winding shaft of the other developing device, the sheet-like member is wound around the winding shaft of the developing device. The timing at which the driving torque generated by being taken is maximum does not overlap with the timing at which the driving torque generated by winding the sheet-like member on the winding shaft of the other developing device is maximized. A developing device.   The sheet-like shape with respect to the take-up shaft of the developing device in a state before transmission of driving force to the take-up shaft of the developing device and the take-up shaft of the other developing device is started by the driving means. The developing device according to claim 5, wherein the slack amount of the member is configured to be different from the slack amount of the sheet-like member with respect to the winding shaft of the another developing device.   The winding shaft of the developing device is formed so that an outer diameter of the winding shaft is different from an outer diameter of a winding shaft of the another developing device. Development device.   The winding shaft is rotated in the predetermined direction when a driving force is transmitted from a driving unit that drives the developing device, and after the predetermined time that is equal to or longer than the time for completing the winding of the sheet-like member has elapsed, The developing device according to claim 1, wherein transmission of driving force from the driving unit is interrupted and rotation is stopped.   The developing device according to claim 8, wherein the predetermined time is within a warm-up operation time until the developing device is mounted on the image forming apparatus main body and a developing process is performed. A rotating member that rotates when the driving force is transmitted from the driving means;
The winding shaft includes a driven gear that meshes with a driving gear installed on the rotating member, and is screwed into a female screw portion fixed to the developing device so that the winding shaft is axially moved. A feed screw for moving is formed in a part of the axial direction,
When the driving force is transmitted from the driving side gear to the driven side gear and the winding shaft rotates, the winding shaft moves in the axial direction from the screwing of the feed screw portion and the female screw portion. 10. The developing device according to claim 8, wherein the engagement of the driving side gear and the driven side gear is released after the predetermined time has elapsed. A developer carrying member disposed to face the image carrier and carrying a developer;
The sheet-like member is formed in a substantially rectangular shape so as to extend in the winding direction, and the outer peripheral surface of the developer carrier is formed inside the developing device in a state before winding by the winding shaft is started. The developing device according to claim 1, wherein the developing device is installed so as to cover and form the closed space. A process cartridge that is detachably attached to the image forming apparatus main body,
12. A process cartridge, wherein 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 and the image carrier.

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