JP2020016844A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

To provide a developing device, a process cartridge, and an image forming apparatus that reduce the likelihood of a reduction in gap between a developing roller and a cover member.SOLUTION: A developing device 13 developing a latent image formed on a surface of a photoreceptor drum 11 (image carrier) is provided with a developing roller 13a that is opposite to the photoreceptor drum 11, an upper cover 13r (cover member) that covers the developing roller 13a, and a pressing member 13n that presses the upper cover 13r from the inside of the developing device 13.SELECTED DRAWING: Figure 2

Description

  The present invention uses a developing device for developing a latent image formed on the surface of an image carrier, a process cartridge having the same, and an electrophotographic system such as a copier, a printer, a facsimile, or a multifunction machine thereof. Image forming apparatus.

  2. Description of the Related Art Conventionally, there has been known a developing device installed in an image forming apparatus such as a copying machine or a printer, in which a cover member (developing case) is installed so as to cover a developing roller (developer carrier) (for example, a developing device). And Patent Document 1.).

Specifically, the developer accommodated in the developing device is agitated and mixed by a conveying member such as a conveying screw. A part of the stirred and mixed developer is supplied to the developing roller. 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 carrier). Then, at the opposed position, a part of the toner in the developer carried on the developing roller moves to the surface of the photosensitive drum. Thus, the latent image formed on the surface of the photosensitive drum is developed to form a toner image.
After that, the developer carried on the developing roller (the developer after the developing process) passes through a position facing the cover member (developing case), and then separates from the developing roller to enter the inside of the developing device. Will be returned.

  In the conventional developing device, the gap between the developing roller and the cover member tends to be narrower than a target range. For this reason, there is a possibility that the developer carried by the developing roller after the developing process is not smoothly transported to the gap between the developing roller and the cover member, but overflows there and leaks out of the apparatus.

  SUMMARY An advantage of some aspects of the invention is to provide a developing device, a process cartridge, and an image forming apparatus in which a gap between a developing roller and a cover member is not easily narrowed.

  The developing device according to the present invention is a developing device that develops a latent image formed on a surface of an image carrier, a developing roller that faces or contacts the image carrier, a cover member that covers the developing roller, And a pressing member for pressing the cover member from the inside of the developing device.

  According to the present invention, it is possible to provide a developing device, a process cartridge, and an image forming apparatus in which a gap between a developing roller and a cover member is not easily narrowed.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating an image forming unit. (A) is a schematic sectional view of the upper part of the developing device in the width direction, and (B) is a schematic sectional view of the lower part of the developing device in the width direction. FIG. 4 is a schematic cross-sectional view of a circulation path of the developing device in a width direction. (A) is a schematic sectional view showing a new developing device at the time of factory shipment, and (B) is a schematic sectional view showing a state where a new developing device is mounted on the image forming apparatus main body. FIG. 3 is a perspective view illustrating a main part of the developing device from a side. FIG. 3 is a perspective view illustrating a main part of the developing device as viewed from the rear side. FIG. 3A is a perspective view showing a developing device, and FIG. 3B is a perspective view showing the developing device with a holding cover and a filter removed. FIG. 4 is a perspective view illustrating a state in which a holding cover is attached to a developing device. FIG. 5 is a perspective view illustrating a state where the pressing member is mounted on the developing device. It is a perspective view showing the state where the pressing member was attached to the cover member. It is a perspective view showing a pressing member. FIG. 5 is an enlarged view showing a procedure for assembling the main parts of the developing device. It is the schematic which shows the state which the pressing member contacted the winding shaft in the width direction.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each of the drawings, the same or corresponding portions are denoted by the same reference characters, and a repeated description thereof will be appropriately simplified or omitted.

First, the overall configuration and operation of the image forming apparatus 1 will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a tandem-type color copying machine as an image forming apparatus; 3, a document conveying unit for conveying a document to a document reading unit; 4, a document reading unit for reading image information of the document; Reference numeral 7 denotes a paper feed unit that stores sheets P such as paper, and 9 denotes a registration roller (timing roller) that adjusts the conveyance timing of the sheets P.
11Y, 11M, 11C and 11BK are photosensitive drums as image carriers on which toner images of respective colors (yellow, magenta, cyan and black) are formed, and 13 is a photosensitive drum of each of the photosensitive drums 11Y, 11M, 11C and 11BK. A developing device that develops an electrostatic latent image formed on the surface; a primary transfer roller that transfers a toner image formed on the surface of each of the photosensitive drums 11Y, 11M, 11C, and 11BK onto the sheet P in a superimposed manner; Is shown.
Reference numeral 17 denotes an intermediate transfer belt as an intermediate transfer body on which a plurality of color toner images are transferred in an overlapping manner; 18, a secondary transfer roller for transferring the color toner image on the intermediate transfer belt 17 onto the sheet P; Denotes a fixing device for fixing an unfixed image on the sheet P, and 28 denotes a toner container containing toner of each color (yellow, cyan, magenta, black) to be supplied to the developing device 13.

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

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

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

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

  The laser beam corresponding to the yellow component is applied to the surface of the first photoconductor drum 11Y from the left in the drawing. At this time, the laser light of the yellow component is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 11Y by the polygon mirror that rotates at a 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 in the drawing, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is irradiated onto the surface of the third photosensitive drum 11C from the left in 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 photoconductor drum 11BK from the left in 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 toner of each color is supplied from the developing device 13 onto the photosensitive drums 11Y, 11M, 11C, and 11BK, and the latent images on the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK are developed (in the developing step). is there.).
Thereafter, the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11BK after the development process reach the portions facing the intermediate transfer belt 17, respectively. Here, a primary transfer roller 14 is provided at each of the opposing portions so as to contact the inner peripheral surface of the intermediate transfer belt 17. Then, at the position of the primary transfer roller 14, the toner images of the respective colors formed on the photosensitive drums 11Y, 11M, 11C, and 11BK are sequentially superimposed and primary-transferred onto the intermediate transfer belt 17 (primary transfer). This is a transfer step.).

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

On the other hand, the intermediate transfer belt 17 (intermediate transfer member) on which the toners of the respective colors on the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK are superimposed and primary-transferred (carried) runs counterclockwise in FIG. Reaches the position facing the secondary transfer roller 18. Then, the color toner image carried on the intermediate transfer belt 17 is secondarily transferred onto the sheet P at a position facing the secondary transfer roller 18 (this is a 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 adhered on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit, and a series of transfer processes on the intermediate transfer belt 17 is completed.

Here, the sheet P conveyed between the intermediate transfer belt 17 and the secondary transfer roller 18 (which is a secondary transfer nip) is conveyed from the sheet feeding unit 7 via the registration roller 9 and the like. It is.
More specifically, the sheet P fed from the sheet feeding unit 7 that stores the sheet P by the sheet feeding roller 8 is guided to the registration roller 9 after passing through the conveyance guide. The sheet P that has reached the registration roller 9 is conveyed toward the secondary transfer nip at the same time.

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

Next, an image forming unit in the image forming apparatus will be described in detail with reference to FIGS.
FIG. 2 is a configuration diagram illustrating an image forming unit. FIG. 3A is a schematic cross-sectional view (horizontal cross-sectional view) of the upper part of the developing device 13 (the position of the second conveying screw 13b2 as a collecting conveying member) viewed in the width direction (longitudinal direction). FIG. 3B is a schematic cross-sectional view of the lower portion of the developing device 13 (the position of the first transport screw 13b1 as a transport member for supply) viewed in the width 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 width direction.
Since each image forming unit has substantially the same structure, the image forming unit and the developing device are illustrated in FIGS. 2 to 4 and the like except for the alphabetical characters (Y, C, M, and 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.
The photoconductor drum 11 as an image carrier is a negatively charged organic photoconductor, and is driven to rotate clockwise by a drive motor.

The charging section 12 is a resilient charging roller formed by forming a medium-resistance urethane foam layer formed of a core metal on which a urethane resin, carbon black as conductive particles, a sulfide agent, a foaming agent, and the like are prescribed, in a roller shape. Examples of the material of the medium resistance layer of the charging unit 12 include urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber (NBR), silicone rubber, and isoprene rubber. A rubber material in which a conductive material such as the above is dispersed, or a foamed material thereof can also be used.
The cleaning unit 15 is provided with a cleaning blade that slides on the photosensitive drum 11 and mechanically removes and collects untransferred toner on the photosensitive drum 11.

  The developing device 13 includes a developing roller 13a as a developer carrier that is opposed to the photoconductor drum 11 with a slight gap therebetween. The photoconductor drum 11 and the magnetic brush are provided at both opposing portions. A developing region (developing nip) that comes into contact is formed. The developing device 13 contains a developer G (two-component developer) including a toner T and a carrier C. Then, 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 later in detail.

Referring to FIG. 1, toner container 28 contains toner T to be supplied into developing device 13 therein. Specifically, based on the information of the toner density (the ratio of the toner in the developer G) detected by the magnetic sensor provided in the developing device 13, the toner is developed from the toner container 28 via the toner conveying pipe. The toner T is appropriately supplied into the apparatus 13 from the toner supply port 13e.
In addition, as the toner T (the toner in the developer G and the toner in the toner container 28) and the carrier C (the carrier in the developer G) used in the present embodiment, known materials may be used. it can.

Hereinafter, the developing device 13 in the image forming apparatus will be described in detail.
2 to 4, etc., the developing device 13 includes a developing roller 13a as a developer carrier, conveying screws 13b1 and 13b2 (auger screws) as conveying members, a doctor blade 13c as a developer regulating member, And so on.
The developing roller 13a is configured such that a sleeve 13a2 formed of a non-magnetic material such as aluminum, stainless steel, brass, or a conductive resin in a cylindrical shape is rotated in a counterclockwise direction by a driving motor as driving means. . Referring to FIG. 3, a magnet 13a1 that forms a plurality of magnetic poles on the peripheral surface (periphery) of the sleeve 13a2 is fixed inside the sleeve 13a2 of the developing roller 13a. The developer G carried on the developing roller 13a is transported with the rotation of the developing roller 13a in the direction of the arrow, and reaches the position of the doctor blade 13c. Then, the developer G on the developing roller 13a is regulated to an appropriate amount at that position, and then is conveyed to a position (developing area) facing the photosensitive drum 11. Then, 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 material, and the developer G accommodated in the supply conveyance path is pumped onto the developing roller 13a. A 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 transport path. On the other hand, at the position of the doctor blade 13c where the magnetic force of the pumping magnetic pole acts, the developer G carried on the developing roller 13a through the doctor gap between the doctor blade 13c and the developing roller 13a is moved at the position of the main magnetic pole. It rises and becomes a magnetic brush in the developing area and comes into sliding contact with the photosensitive drum 11. Thus, the toner T in the developer G carried on the developing roller 13a adheres to the latent image on the photosensitive drum 11. After that, the developer G that has passed the position of the main magnetic pole is conveyed by a plurality of conveying magnetic poles to and from the upper cover 13r (cover member), and then conveyed to the position of the magnetic pole away from the developer. Then, at the position of the developer release magnetic pole, a repulsive magnetic field (a magnetic field acting in a direction away from the developing roller 13a) acts on the carrier, and the developer G that has been carried on the developing roller 13a after the developing process is removed. It is detached from the developing roller 13a. The separated 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, doctor blade 13c as a developer regulating member is a non-magnetic plate-like member (part of which may be formed of a magnetic material) disposed below developing roller 13a. is there. The doctor blade 13c opposes the developing roller 13a below and functions as a developer regulating member that regulates the amount of the developer G carried on the developing roller 13a.

Then, 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 stir and mix the developer G accommodated in the developing device 13 while circulating the developer G in the width direction (perpendicular to the plane 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 width direction (rotation 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 (in the direction indicated by the white arrow in FIG. 3B). The first transport screw 13b1 rotates counterclockwise in FIG.

The second transport screw 13b2 (recovery transport member) is disposed above the first transport screw 13b1 and at a position facing the developing roller 13a. Then, the developer G detached from the developing roller 13a (a developer G forcibly detached from the developing roller 13a by the developer releasing magnetic pole after the developing step and detached in the white arrow direction in FIG. 3A) ) Is conveyed horizontally in the width direction (conveyance in the right direction indicated by the broken arrow in FIG. 3A). In the present embodiment, the rotation direction of the second conveying screw 13b2 is set to be opposite (the clockwise direction in FIG. 2) to the rotation direction of the developing roller 13a.
The second transport screw 13b2 transfers the developer G circulated from the downstream side of the transport path of the first transport screw 13b1 via the first relay portion 13f to the upstream side of the transport path of the first transport screw 13b1. The sheet is conveyed via the relay section 13g (conveyance indicated by a dashed line arrow in FIG. 3).
The two transport screws 13b1 and 13b2 are arranged so that the rotation axes are substantially horizontal, similarly to the developing roller 13a and the photosensitive drum 11. Each of the two transport screws 13b1 and 13b2 has a screw portion spirally wound around a shaft portion.

The two transport screws 13b1 and 13b2, together with the developing roller 13a, form one drive system by a gear train, and are configured to be rotationally driven by a drive motor as drive means. That is, the drive of the drive motor is controlled by the control unit, so that the two transport screws 13b1 and 13b2 are rotationally driven together with the developing roller 13a.
More specifically, the driving force of the developing roller 13a is directly transmitted from the driving motor to the shaft portion at one end in the width direction (the direction perpendicular to the paper surface of FIG. 2 and the horizontal direction of FIG. 3). A coupling is provided. Further, a gear is provided on a shaft portion on one end side in the width direction of the developing roller 13a, and this gear meshes with a gear provided on a shaft portion on one end side in the width direction of the first transport screw 13b1 via an idler. are doing. A first gear 13x is provided on a shaft portion on the other end side in the width direction of the first transport screw 13b1, and this first gear 13x is attached to a shaft portion on the other end side in the width direction of the second transport screw 13b2. It meshes with the installed second gear 13y (see FIGS. 6 and 7). Here, the second gear 13y (drive-side gear) is configured to mesh with a third gear 13z (driven-side gear) provided on the winding shaft 13k, which will be described later in detail. .
In the present embodiment, a drive motor (drive means) for driving the developing device is provided independently of a drive motor for rotating and driving the photosensitive drum 11 and the like as a development drive motor.

Here, the transport route (supply transport route) by the first transport screw 13b1 and the transport route (recovery transport route) by the second transport screw 13b2 are separated by a wall (partition 13d).
Referring to FIGS. 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 the same. They are communicated via two relays 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.
Also, with reference to FIGS. 3 and 4, the downstream side of the transport path by the first transport screw 13b1 and the upstream side of the transport path by the second transport screw 13b2 communicate via the first relay unit 13f. I have. Then, the developer G that has not been supplied onto the developing roller 13a in the supply transport path by the first transport screw 13b1 stays in the vicinity of the first relay section 13f and rises up, and rises through the first relay section 13f. It is transported (supplied) to the upstream side of the recovery transport path by the two transport screw 13b2.
In order to improve the transportability of the developer in the first relay portion 13f (transfer of the developer from the supply transport path to the recovery transport path in the direction of gravity), the first transport screw 13b1 is used. A paddle-shaped portion or a screw portion in which a screw winding direction is formed in a reverse direction may 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 width direction (longitudinal direction) in the developing device 13 is formed by the two transport 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 dashed arrow in FIGS. As described above, the supply path of the developer G to the developing roller 13a (the supply transport path by the first transport screw 13b1) and the recovery path of the developer G separated from the developing roller 13a (the second transport screw) 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 provided in the transport path of the second transport screw 13b2. Then, based on the information on the toner concentration detected by the magnetic sensor, the toner is directed from the toner container 28 into the developing device 13 through the toner supply port 13e (disposed near the first relay portion 13f). New toner T is supplied.
Referring to FIGS. 3 and 4, the toner supply port 13e is located on the upstream side of the transport path by the second transport screw 13b2 and at a position away from the developing area (the width direction of the developing roller 13a). Outside).) By arranging the toner supply port 13e in the vicinity of the first relay portion 13f in this manner, the developer separated from the developing roller 13a falls down from above the supply toner having a small specific gravity in the collection conveyance path, and the collection conveyance path. It is possible to sufficiently disperse and mix the replenishment toner with respect to the developer over a relatively long time toward the downstream side of the developer.
In the present embodiment, the toner supply port 13e is provided in the recovery transport path by the second transport screw 13b2. However, the position of the toner supply port 13e is not limited to this. It can also be located above the upstream side of the path.

Here, the developing device 13 in the present embodiment is installed detachably (replaceable) with respect to the image forming apparatus main body 1 and becomes a new one (including a recycled product) in a predetermined replacement cycle. Be exchanged.
Then, referring to FIG. 5, the developing device 13 in the present embodiment is filled with the developer G (pre-packed at the time of factory shipment) housed in the developing device 13 until the use in the image forming apparatus main body 1 is started. In order to prevent leakage of the developer G as a preset agent, a sheet-like member 13m that isolates the inside of the developing device 13 so as to form a closed space in which the developer G is stored is formed. Is provided.
Further, the developing device 13 is disposed in a predetermined direction (FIG. 5 ( The winding shaft 13k that winds the sheet-shaped member 13m in a direction intersecting the width direction of the sheet-shaped member 13m (ie, a direction substantially orthogonal to the width direction of the sheet-shaped member 13m). Is provided.

  More specifically, the sheet-shaped member 13m is made of a material such as polyurethane rubber having a thickness of about 0.1 to 0.5 mm, and extends in the winding direction (the direction of the white arrow in FIG. 5B). It is formed in a substantially rectangular shape. The sheet-shaped member 13m has a length in the width direction set in accordance with a range in the width direction so as to isolate the inside of the developing device 13, and isolates the inside of the developing device 13 and uses a winding shaft 13k. The length in the winding direction is set to be 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 member 13m installed as shown in FIG. That is, in the factory, the developer G is contained 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 conveying path and the collecting conveying 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, sheet-shaped member 13m is a virtual plane connecting the tip of partition 13d and the tip of doctor blade 13c inside developing device 13. However, the portion extended toward the doctor blade 13c is adhered to the exterior of the developing device 13 on the doctor blade 13c side with relatively light force (or one end of the sheet-like member 13m). Then, the other end of the sheet-shaped member 13m is wound around a winding shaft 13k, and tension is applied to the sheet-shaped member 13m. This prevents the developer from leaking out from the first transport screw 13b1 (supply screw) side.
Similarly, in the sheet-shaped member 13m, a virtual plane (substantially straight in the drawing) connecting the tip of the partition 13d and the opening 13r1 formed in the upper cover 13r is extended to the winding shaft 13k. The other end of the sheet-shaped member 13m is wound around the winding shaft 13k, and tension is applied to the sheet-shaped member 13m. This prevents the developer from leaking from the second transport screw 13b2 (recovery screw) side.
If the sheet-like member 13m is bonded (or heat-welded) to the tip of the partition 13d and the tip of the doctor blade 13c with relatively light force, respectively, the sheet-like member 13m is formed in the developing device 13. Hermeticity will be further increased.

Further, referring to FIG. 5 (or FIGS. 6 and 7) and the like, the ceiling portion of the upper cover 13r as a cover member functioning as a part of the exterior of the developing device 13 and the housing (the developing device 13 The winding shaft 13k is rotatably installed at the outside of the inside where G is housed.). Then, by rotating the winding shaft 13k, the end of the sheet-shaped member 13m (the end in the winding direction) can be wound on the winding shaft 13k so that the sheet-shaped member 13m can be wound around the outer periphery of the winding shaft 13k. Is fixed by bonding or the like.
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 of the upper cover 13r (cover member) in the width direction (perpendicular to the paper surface of FIG. 5). ) So that the sheet-like member 13m can move from the inside of the developing device 13 to the outside through the opening 13r1 (to be wound up). In the present embodiment, the opening 13r1 is configured to open in a vertical direction together with a vent 13r2 described later.

As shown in FIG. 5 (A), the developing device 13 configured as described above is configured as shown in FIG. 5 (B) while the developer G contained therein is hermetically sealed by the sheet-like member 13m. As shown, it is mounted on the image forming apparatus main body 1. Examples of such an embodiment include (1) a case where the image forming apparatus is shipped with a new developing device 13 attached to a new image forming apparatus main body 1, and (2) a case where the image forming apparatus 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 above-described cases, before the use of the new developing device 13 in the image forming apparatus 1 (developing process) is started, the winding shaft 13k is rotated so that the sealed / sealed state is achieved. The sheet 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 on which the sheet-like member 13m in the closed / sealed state is installed is mounted on the image forming apparatus main body 1. Before starting, by rotating the winding shaft 13k, the sheet-like member 13m is moved in the direction of the white arrow and wound by the winding shaft 13k, and normal image formation is performed in a state as shown in FIG. A process (development step) is performed.
In the present embodiment, the winding shaft 13k is formed of a metal material having a diameter of about 3 to 6 mm.

  As described above, in the present embodiment, even when the developing device 13 is transported alone as a replacement device, the developing device 13 is transported with the developing device 13 attached to the image forming apparatus main body 1 at the time of shipment. Even in this case, since the developer G (preset agent) stored in advance in the developing device 13 is sealed by the sheet-like member 13m, the developer G (preset agent) is stored in the developing device 13 due to vibration generated during transportation or the like. The problem that the developer G (preset agent) leaks out of the developing device 13 can be prevented.

In particular, in the present embodiment, as shown in FIG. 5, the sheet-shaped member 13m covers the outer peripheral surface of the developing roller 13a inside the developing device 13 before the winding by the winding shaft 13k is started. It is installed so that a closed space is formed.
This prevents the developer G from being carried on the surface of the developing roller 13a during transportation, so that it is possible to reliably prevent the user from touching the surface of the developing roller 13a and being stained 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 a 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 also possible to prevent inconveniences that may occur.

In this embodiment, as shown in FIGS. 2 and 5, an opening 13r1 for removing the sheet-like member 13m from the inside of the developing device 13 is formed in the upper cover 13r that is not buried in the developer G. . This makes it possible to make the developer G less likely to leak out of the opening 13r1 during normal image formation than when an opening is formed in the lower cover 13u buried in the developer G.
In the present embodiment, even if the developer G leaks from the opening 13r1 as described above, the pressing cover 13s that covers the space in which the winding shaft 13k is installed is further provided. The developer G does not leak out of the developing device 13.

In the present embodiment, the take-up shaft 13k rotates in a predetermined direction (counterclockwise in FIG. 5B) when a driving force is transmitted from a drive motor (drive unit) that drives the developing device 13. Then, the transmission of the driving force from the driving motor is interrupted and the rotation is stopped after a predetermined time that is equal to or longer than the time for completing the winding of the sheet-shaped member 13m. Here, the above-mentioned “predetermined time” is a time of a warm-up operation until the developing device 13 is mounted on the image forming apparatus main body 1 and a developing process is performed. That is, when the new developing device 13 is mounted on the image forming apparatus 1 (or when the operation of the new image forming apparatus 1 with the new developing device 13 mounted is started), the image forming conditions are changed. During the warming-up operation in which adjustment and the like are performed, the drive motor starts rotating the winding shaft 13k from the state shown in FIG. 5B, and the winding operation of the sheet-like member 13m is performed. Then, after the winding of the sheet-shaped member 13m is completed (after the state shown in FIG. 2), the drive transmission from the drive motor to the winding shaft 13k is interrupted, and the winding shaft 13k (the sheet-shaped member 13m is wound). The normal image forming operation (development step) is performed in a state where the rotation is stopped.
Further, at the time of winding the sheet-shaped member 13m, 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-shaped member 13m. The attached developer will be removed. Further, the leading end of the partition 13d and the opening 13r1 through which the sheet-like member 13m passes respectively scrape off the developer attached to the surface of the sheet-like member 13m.

  By stopping the rotation of the winding shaft 13k after the winding of the sheet-shaped member 13m is completed in this way, the winding shaft 13k is permanently idle driven in conjunction with the driving of the developing device 13, thereby causing an abnormality. It is possible to suppress a problem that a noise is generated or a state in which the driving torque is always large. In addition, when the normal image forming operation is started, the rotation of the winding shaft 13k is stopped, so that a problem that the vibration due to the rotation of the winding shaft 13k affects image formation can be suppressed.

Referring to FIGS. 6 and 7, a mechanism for interrupting the transmission of the driving force from the driving motor (driving means) to the winding shaft 13k after the predetermined time has elapsed as described above will be described in detail.
As described above, the developing device 13 is provided with the second transport screw 13b2 (rotating member) that is rotated by a driving force transmitted from a driving motor (driving unit) for the developing device 13 via a gear train. ing. A third gear 13z (driven gear) meshing with a second gear 13y (drive gear) provided on the second transport screw 13b2 is provided on the winding shaft 13k. Further, a feed screw for screwing with a female screw portion 13p (nut) fixed to the ceiling of the developing device 13 to move the winding shaft 13k in the axial direction (width direction) is provided on the winding shaft 13k. The portion 13q is formed at a part in the axial direction.

Then, a driving force is transmitted from the second gear 13y (drive-side gear) to the third gear 13z (driven-side gear), and the winding shaft 13k rotates, thereby screwing the feed screw portion 13q and the female screw portion 13p. The take-up shaft 13k moves in the axial direction (the direction of the arrow in FIGS. 6 and 7 and is the width direction), and after a predetermined time has elapsed, the second gear 13y and the third gear 13z mesh. 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 proceeds, the third gear 13z slides in the axial direction together with the winding shaft 13k, and the third gear 13z does not mesh with the second gear 13y ( At this point, 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 the number of rotations (the number of teeth) of the two gears 13y and 13z, the screw position and the screw length of the feed screw portion 13q and the female screw portion 13p, etc. Is set.
With such a configuration, the developing roller 13a and the transport screws 13b1, 13b2 can be driven by using the driving force of the driving motor for driving the developing device 13 without independently providing a motor for driving the winding shaft 13k. Without interrupting the drive of the winding shaft 13k. Therefore, it is possible to reduce the size and weight of the developing device 13.
In the present embodiment, the third gear 13z (driven gear) installed on the winding shaft 13k is configured to mesh with the second gear 13y installed on the second transport screw 13b2. The embodiment is not limited to this. For example, a configuration may be adopted in which a gear (driven gear) provided on the winding shaft 13k is meshed with a first gear 13x provided on the first transport screw 13b1. it can.

Hereinafter, the characteristic configuration and operation of the developing device 13 according to the present embodiment will be described.
As described above with reference to FIG. 2 and the like, the developing device 13 according to the present embodiment includes a developing roller 13a facing the photosensitive drum 11 (image carrier) and a cover member that covers the developing roller 13a. The upper cover 13r is provided.
The upper cover 13r (cover member) is formed so as to cover the upper part of the developing device 13 (a range including the upper part of the developing roller 13a). Together with the holding cover 13s for covering the shaft 13k and a filter 13t to be described later, it functions as an exterior or a housing of the developing device 13. In the present embodiment, the upper cover 13, the lower cover 13u, and the holding cover 13s are all formed of a resin material such as ABS and PC.

Referring to FIG. 2, in the present embodiment, gap H (casing gap) between developing roller 13a and upper cover 13r is set to be in the range of 0.6 to 1.0 mm. .
When the casing gap H becomes smaller than 0.6 mm, the developer G carried by the developing roller 13a after the development process is not smoothly transported to the gap H between the developing roller 13a and the upper cover 13r, and the developer G is not conveyed. Spillover from the developing device 13 to the outside.
On the other hand, if the casing gap H is larger than 1.0 mm, the developer G carried on the developing roller 13a is unlikely to slide on the inner peripheral surface of the upper cover 13r, and the developing device 13 It is difficult to form a suction airflow toward the inside of the device, and toner scattering from the developing device 13 (toner scattering around the development area) is likely to occur.
By maintaining the casing gap H in an appropriate range, leakage of the developer G and toner scattering can be reduced.

Here, with reference to FIG. 2, FIG. 8, FIG. 9, etc., a vent 13r2 (opening) that allows ventilation inside and outside the developing device 13 is formed in the upper cover 13r as a cover member. . The developing device 13 is provided with a filter 13t that covers the vent 13r2 of the upper cover 13r (cover member) and collects and vents the toner.
In other words, a flow path for sending air from the inside of the developing device 13 to the outside is formed in the upper cover 13r. A filter 13t is provided so as to cover a part of the flow path. The filter 13t is formed of a mesh smaller than the particle size of the toner T and the carrier C, and is formed so that only air can pass.
Due to the suction airflow in the casing gap H described above, the internal pressure of the developing device 13 tends to increase, and if the internal pressure increases, toner scatters from the gap of the developing device 13. On the other hand, in the present embodiment, since the ventilation port 13r2 covered with the filter 13t is provided, only the ventilation is performed while collecting the toner T and preventing the toner T from scattering to the outside. 13 is suppressed. That is, toner scattering due to an increase in the internal pressure of the developing device 13 is prevented.

Here, with reference to FIG. 2 and FIGS. 8 to 10, in the developing device 13 in the present embodiment, a pressing cover 13 s is detachably provided separately from the upper cover 13 r and the lower cover 13 u.
The presser cover 13s is to be fitted to the upper cover 13r (cover member) in a state where the filter 13t is installed in the vent 13r2, and to hold the filter 13t between itself and the upper cover 13r. . In other words, the presser cover 13s presses the filter 13t installed on the upper cover 13r from above in order to prevent the filter 13t from falling off.
In the present embodiment, the holding cover 13s is formed so as to cover the winding shaft 13k with the upper cover 13r. As a result, most of the winding shaft 13k is not exposed to the outside of the apparatus, so that a user or a service person erroneously applies a strong external force to the winding shaft 13k to deform the winding shaft 13k. Can be prevented.
In the present embodiment, the pressing cover 13s is fitted to the upper cover 13r by patching.

Here, with reference to FIG. 2, FIG. 10, FIG. 11, etc., the developing device 13 in the present embodiment is provided with a pressing member 13n that presses the upper cover 13r (cover member) from inside the developing device 13. ing.
Referring to FIG. 13D and the like, the pressing member 13n raises the upper cover 13r from the inside of the developing device 13 on the side away from the developing roller 13a with respect to the ventilation port 13r2 (see FIG. 13D). (In the direction of the white arrow).
More specifically, as shown in FIG. 13D, a vent 13r2 (filter 13t) is arranged between the developing roller 13a and the pressing member 13n. In the present embodiment, the pressing member 13n is a thin elastic member made of PET (polyethylene terephthalate) having a thickness of about 75 μm. The pressing member 13n has its root portion (a portion other than the distal end portion 13n1) supported by the upper cover 13r, the pressing cover 13s, and the winding shaft 13k, and its distal end portion 13n1 (see FIG. 12). Is a free end, and presses the upper cover 13r upward from below by its elastic force. In the present embodiment, the length in the width direction of the tip portion 13n1 is set to about 15 to 30 mm.

  By providing the pressing member 13n that presses the upper cover 13r from the inside of the developing device 13 in this manner, a force for always holding the upper cover 13r upward acts on the upper cover 13r. The problem that the gap H (casing gap) with the cover 13r becomes narrower than the intended range is less likely to occur. Therefore, since the casing gap H is narrow, the developer G carried by the developing roller 13a after the developing process is not smoothly transported to the casing gap H, and is less likely to overflow and leak out of the apparatus. Become.

  In particular, in the present embodiment, the upper cover 13r is formed of a relatively thin resin material in order to reduce the weight and cost of the developing device 13. Therefore, as compared with the case where the upper cover 13r is formed of a heavy metal material, the mechanical strength of the upper cover 13r is reduced, and the upper cover 13r is bent such that the casing gap H is narrowed (a downwardly convex shape). ). Therefore, the effect of installing the pressing member 13n as in the present embodiment is increased.

Further, in the present embodiment, as described above with reference to FIG. 5 and the like, the preset agent is stored in the developing device 13 from the time of shipment from the factory until the use of the developing device 13 is started at the user site. In order to accommodate the developer G, the sheet-like member 13 m is installed so as to isolate the inside of the developing device 13. As shown in FIG. 5 and FIG. 13C, the sheet-like member 13m keeps the pressing member 13n up until the use of the developing device 13 is started (until it is wound on the winding shaft 13k). Since the upper cover 13r is interposed between the upper cover 13r and the cover 13r, the upper cover 13r is pressed upward from below by the tension of the sheet-like member 13m, thereby preventing the casing gap H from being narrowed.
However, as shown in FIG. 2 and FIG. 13 (D), when the use of the developing device 13 is started and the sheet-like member 13m is wound around the winding shaft 13k, the upper cover 13r by such a sheet-like member 13m is formed. , There is a possibility that the casing gap H may be narrowed as it is. Therefore, the effect of installing the pressing member 13n as in the present embodiment is particularly large.
In particular, in the manufacturing process, as shown in FIGS. 5A and 13C, the casing gap H is adjusted so that the casing gap H is in a target range in a state where the sheet-like member 13m is installed in the developing device 13. Is performed, there is a possibility that the casing gap H becomes smaller than the target range after the sheet-like member 13m is wound up (when the use of the apparatus is started.). Therefore, the effect of installing the pressing member 13n as in the present embodiment is increased.

Here, referring to FIGS. 2, 13 and the like, in the present embodiment, distal end 13n1 (see FIG. 12) of pressing member 13n is inserted into upper cover 13r as a cover member from outside developing device 13. A possible opening 13r1 is formed. As described above with reference to FIG. 5 and the like, the opening 13r1 allows the sheet-shaped member 13m to move from the inside of the developing device 13 to the outside (to be wound by the winding shaft 13k). It is for. That is, the pressing member 13n is inserted into the opening 13r1 in addition to the sheet-like member 13m.
With this configuration, the number of openings in the developing device 13 can be reduced as compared with the case where the opening for the pressing member 13n is provided separately from the opening for the sheet-shaped member 13m. It becomes easy to secure the airtightness in the case.

Then, as shown in FIGS. 10 and 13, the pressing member 13n is detachably mounted on the developing device 13 with the pressing cover 13s removed. Then, the posture of the pressing member 13n is restricted by the pressing cover 13s attached to the developing device 13.
By thus configuring the pressing member 13n so as to be detachable, replacement work and maintenance work of the pressing member 13n become easy. Further, the grip 13n2 (see FIG. 12) side of the pressing member 13n is held by the pressing cover 13s so as not to shift upward, so that the attitude of the pressing member 13n in the developing device 13 is determined, and the pressing of the pressing member 13n against the upper cover 13r is performed. The pressing force of the member 13n is stabilized, and the casing gap H is also stabilized.

In particular, when it is desired to adjust the pressing force of the pressing member 13n according to the size of the casing gap H, an operation of replacing the pressing member 13n with a different thickness and a different length in the width direction occurs. On the other hand, in the present embodiment, since the pressing member 13n is configured to be detachable, such work is also facilitated.
Specifically, when the casing H of the developing roller 13a and the upper cover 13r is small, the pressing member 13n has at least one of the thickness and the length in the width direction larger than when the casing gap H is large. Will be set to That is, the thickness and the length in the width direction of the pressing member 13n are optimized according to the size of the casing gap H, and the casing gap H falls within a target range by optimizing the elastic force (stiffness) of the pressing member 13n. It will be adjusted to become.

Here, as shown in FIG. 12, the pressing member 13n is a thin plate-shaped member provided with a tip portion 13n1 and a grip portion 13n2, and has a substantially boomerang-like shape in a direction of being inserted into the opening 13r1. Wing-shaped stopper portions 13n3 are formed at both ends in the width direction.
The distal end 13n1 of the pressing member 13n is located at the end opposite to the grip 13n2 (opposite to the opening 13r1 in the insertion / removal direction). The tip 13n1 is formed so as to be inserted into the opening 13r1 formed in the upper cover 13r from outside the developing device 13. Then, the distal end portion 13n1 of the pressing member 13n comes into contact with the upper cover 13r, and the contact portion serves as an action point for applying a pressing force to the upper cover 13r.

On the other hand, as shown in FIG. 13B, the holding portion 13n2 of the pressing member 13n is formed so as to be exposed to the outside of the developing device 13 in a state where the pressing cover 13s is removed and can be held.
Specifically, the grip 13n2 is formed so as to be inclined with respect to the distal end 13n1 in the insertion direction of the pressing member 13n (the direction of insertion into the opening 13r1 and the horizontal direction in FIG. 13). That is, the pressing member 13n is formed in a substantially boomerang shape (U shape) from the grip portion 13n2 to the tip portion 13n1. The grip portion 13n2 is long enough to be gripped by a worker such as an engineer or a serviceman (the length in the insertion direction), and even when the distal end portion 13n1 is inserted into the developing device 13. The setting is made so that the worker can sufficiently grasp it.

By providing the grip 13n2 on the pressing member 13n in this manner, the work of assembling and removing the pressing member 13n from the developing device 13 by the operator becomes easy.
In addition, by forming the pressing member 13n in a substantially boomerang shape, a plurality of portions of the pressing member 13n can easily come into contact with any of the upper cover 13r, the holding cover 13s, and the winding shaft 13k. This makes it easier to determine the attitude of the pressing member 13n in the developing device 13. Therefore, the pressing force of the pressing member 13n against the upper cover 13r is stabilized, and the casing gap H is also stabilized.

On the other hand, the stopper 13n3 of the pressing member 13n contacts the edge of the opening 13r1 in the upper cover 13r (cover member) to determine the length of the tip 13n1 inserted into the developing device 13. is there.
More specifically, as shown in FIG. 12, the stopper 13n3 is formed so as to be inclined and protrude from both ends in the width direction of the pressing member 13n with respect to the tip 13n1. Specifically, in the present embodiment, the stopper portion 13n3 is inclined so as to stand upward (in the same bending direction as the grip portion 13n2) by 30 to 45 degrees with respect to the surface on which the tip portion 13n1 is formed. are doing.
Then, when the distal end portion 13n1 of the pressing member 13n is inserted into the opening 13r1, the end surface of the stopper portion 13n3 (the portion shown by a dashed line in FIG. 12) comes into contact with the edge of the opening 13r1. Therefore, the pressing member 13n can no longer be inserted, and the length of the tip portion 13n1 inserted into the developing device 13 is determined. That is, the distal end 13n1 of the pressing member 13n is inserted into the developing device 13 by a target length.

Thereby, the pressing force of the pressing member 13n against the upper cover 13r is stabilized, and the casing gap H is also stabilized.
In addition, by providing the blade-shaped stopper portion 13n3 inclined with respect to the plane on which the tip portion 13n1 is formed, a stronger stiffness is provided on the plane on which the tip portion 13n1 is formed than when there is no such stopper portion 13n3. Is formed. For this reason, the elastic force of the distal end portion 13n1 can be strengthened even though the thickness of the pressing member 13n is thin.

Here, in the present embodiment, the pressing member 13n is formed so as to make linear contact with the winding shaft 13k.
Specifically, as shown in FIG. 14, the wing-shaped stopper portion 13n3 that is inclined upward in the pressing member 13n comes into contact with the winding shaft 13k while being curved so as to spread in the width direction. That is, the portion of the stopper portion 13n3 surrounded by the broken line in FIG. 14 comes into line contact with the winding shaft 13k.
With this configuration, the winding when the winding shaft 13k rotates and winds the sheet-like member 13m is compared with the case where the pressing member 13n is configured to make surface contact with the winding shaft 13k. The sliding resistance between the shaft 13k and the pressing member 13n can be reduced. Therefore, the winding operation by the winding shaft 13k is performed smoothly.

Here, in the present embodiment, the pressing member 13n presses the upper cover 13r from the inside of the developing device 13 with the front end portion 13n1 abutting on the central portion in the width direction of the upper cover 13r inside the developing device 13. Is configured.
That is, the pressing member 13n does not press the upper cover 13r over the entire area in the width direction, but presses only the central portion in the width direction of the upper cover 13r (the range indicated by the double-headed arrow in FIG. 10). It is configured.
The reason for this configuration is that, as described above, the upper cover 13r is bent downward at the center in the width direction. For this reason, the bending of the upper cover 13r can be efficiently corrected by applying the pressing force of the pressing member 13n to the central portion in the width direction where the upper cover 13r is most likely to bend. Therefore, it becomes easy to set the casing gap H to a target range across the width direction.

Finally, the relationship between the procedure for assembling the pressing member 13n and the winding of the sheet-like member 13m will be described with reference to FIGS.
First, in a manufacturing process in a factory, as shown in FIGS. 13A and 13B, a developing device 13 in which a sheet-like member 13m is mounted and assembled to a state in which a developer G as a preset agent is stored. The filter 13t is set so as to cover the vent 13r2. Further, the pressing member 13n is set so that the distal end 13n1 of the pressing member 13n is inserted into the opening 13r1.
Thereafter, as shown in FIGS. 13B and 13C, the pressing cover 13s is set on the developing device 13 on which the filter 13t and the pressing member 13n are set. Then, the developing device 13 in the state of FIG. 13C is shipped from the factory.
Thereafter, as shown in FIG. 13D, the user winds up the sheet-like member 13m, and only the pressing member 13n presses the upper cover 13r upward.
When the pressing member 13n is replaced with respect to the developing device 13 (in the state of FIGS. 2 and 13D) after the start of use, first, FIGS. The pressing cover 13s is removed from the developing device 13 in the state D), and then the pressing member 13n is removed. Then, a replacement pressing member 13n is mounted in place of the removed pressing member, and finally, the pressing cover 13s is fitted.

As described above, in the present embodiment, the developing device 13 that develops the latent image formed on the surface of the photoconductor drum 11 (image carrier) includes the developing roller 13 a facing the photoconductor drum 11, An upper cover 13r (cover member) that covers the roller 13a and a pressing member 13n that presses the upper cover 13r from inside the developing device 13 are provided.
Thereby, it is possible to make it less likely that the gap between the developing roller 13a and the upper cover 13r (cover member) becomes narrow.

In the present embodiment, the second transfer screw 13b2 functioning as a collection screw is installed above the first transfer screw 13b1 functioning 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 transfer screw that functions as a recovery screw is installed below the first transfer screw that functions as a supply screw, and a doctor blade is installed. Is a two-component developing type developing device installed above the developing roller, a two-component developing type developing device in which a plurality of conveying members are arranged in a horizontal direction, or only a toner containing no carrier as a developer is used. The present invention can be applied to a developing device of the one-component developing system.
In the present embodiment, the present invention is applied to the developing device 13 in which the developing roller 13a faces the photosensitive drum 11 (image carrier) with a gap therebetween. The present invention can also be applied to a developing device of a contact-type one-component developing type in which is disposed so as to contact the image carrier.
Then, even in such a case, the same effect as that of the present embodiment can be obtained.

Further, in the present embodiment, the present invention is applied to the developing device 13 configured as a unit that is detachably attached to the image forming apparatus main body 1 by itself. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to a developing device formed as a process cartridge. In this case, the workability of maintenance of the image forming unit is improved.
In the present application, the “process cartridge” includes 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 unit that cleans the image carrier. At least one of the cleaning unit and the image carrier are integrated and defined as a unit that is detachably attached to the image forming apparatus main body.

Further, in the present embodiment, by providing the feed screw portion 13q to the winding shaft 13k, the winding shaft 13k is moved in the axial direction to a position where the gears 13y and 13z are disengaged from each other, and the driving force from the driving unit is provided. It was configured to be able to shut off. On the other hand, without providing the feed screw portion 13q, the driven gear 13y and the driven gear 13z are each a helical gear, and the driven gear 13z installed on the winding shaft 13k is meshed with the driving gear 13y. By receiving the component force moving in the axial direction, the winding shaft 13k is moved in the axial direction to a position where the gears 13y and 13z are disengaged from each other, so that the driving force from the driving means can be cut off. it can.
Further, in the present embodiment, the winding shaft 13k is configured to be automatically rotated by the driving unit. However, the winding shaft 13k may be configured to be rotated manually.
Then, even in such a case, the same effect as that of the present embodiment can be obtained.

  It is to be noted that the present invention is not limited to the present embodiment, and it is apparent that the present embodiment can be appropriately modified other than the ones suggested in the present embodiment within the scope of the technical idea of the present invention. is there. Further, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, but can be set to a number, position, shape, and the like suitable for carrying out the present invention.

1 image forming apparatus (image forming apparatus main body),
11, 11Y, 11C, 11M, 11BK Photoconductor drum (image carrier),
13 developing device (developing section),
13a developing roller (developer carrier),
13c doctor blade (developer regulating member),
13k winding shaft,
13m sheet-like member,
13n pressing member,
13n1 tip,
13n2 gripper,
13n3 stopper part,
13r Upper cover (cover member),
13r1 opening,
13r2 vent,
13s presser cover,
13t filter,
13u lower cover,
G developer (two-component developer), T toner, C carrier.

JP-A-2006-148826

Claims (13)

A developing device for developing a latent image formed on the surface of the image carrier,
A developing roller facing or contacting the image carrier;
A cover member that covers the developing roller,
A pressing member for pressing the cover member from inside the developing device,
A developing device comprising: The cover member is formed so as to cover the upper part of the developing device, and includes a ventilation port that allows ventilation inside and outside the developing device,
A filter that covers the ventilation port of the cover member and collects and vents toner.
A press cover that fits into the cover member in a state where the filter is installed in the vent, and holds the filter between the cover member and the cover member.
With
The developing device according to claim 1, wherein the pressing member presses the cover member from the inside of the developing device on a side away from the developing roller with respect to the ventilation port. The cover member has an opening through which the distal end of the pressing member can be inserted from outside the developing device,
The said pressing member is installed so that attachment and detachment is possible with respect to the said developing device in the state where the said holding | maintenance cover was removed, The attitude | position is restrict | limited by the said holding | maintenance cover attached to the said developing device, The claim Item 3. The developing device according to Item 2.   4. The pressing member according to claim 3, wherein the front end of the pressing member abuts on a central portion in a width direction of the cover member inside the developing device, and presses the cover member from the inside of the developing device. 5. Developing device.   The developing device according to claim 3, wherein the pressing member includes a gripper that is exposed to the outside of the developing device in a state where the pressing cover is removed and can be gripped.   4. The stopper according to claim 3, wherein the pressing member includes a stopper that abuts on an edge of the opening in the cover member and determines a length of the tip inserted into the developing device. 5. Item 6. The developing device according to any one of Items 5. A sheet-like member that isolates the inside so that a closed space containing the developer is formed inside the developing device;
The sheet-shaped member is rotated in a predetermined direction so that the sheet-shaped member is removed from the inside of the developing device to the outside through the opening when the use of the sheet-shaped member is started in the image forming apparatus main body. A winding shaft that winds the sheet-shaped member with a direction to be taken as a winding direction,
With
The developing device according to claim 3, wherein the pressing cover is formed to cover the winding shaft between the pressing cover and the cover member.   The developing device according to claim 7, wherein the pressing member is formed so as to make linear contact with the winding shaft.   The developing device according to claim 1, wherein the pressing member is a thin plate member having elasticity.   When the gap between the developing roller and the cover member is small, the pressing member is set so that at least one of the thickness and the length in the width direction is larger than when the gap is large. The developing device according to claim 1, wherein:   11. The developer control device according to claim 1, further comprising: a developer regulating member that opposes the developing roller at a lower position and regulates an amount of the developer carried on the developing roller. Developing device. A process cartridge detachably mounted to the image forming apparatus main body,
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.

Images