JP2579466B2 - Developing device for image generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a developing device for an image generator, and more particularly, to a developing device that applies toner to an electrostatic latent image and develops the toner image in the image generator.

<Prior Art> As is well known to those skilled in the art, an electrostatic copying machine or an electrostatic printing method of forming an electrostatic latent image on an electrophotographic photosensitive member and then developing the electrostatic latent image into a toner image Image generators such as printers are widely used in practice. In such an image generator, a developing device that applies toner to an electrostatic latent image to develop the toner image generally includes a developing chamber and the developing chamber for applying toner to the electrostatic latent image to be developed. And a toner storage chamber communicated with the developing chamber through a toner discharge opening.

In the developing device of the above-described embodiment, instead of installing the image generating apparatus at the place of use and filling the toner containing chamber with toner when actually starting use, the toner containing chamber is previously prepared at the time of manufacturing or the like. There is a tendency that a so-called toner pre-filling method is adopted in which a toner is filled and supplied to a user in such a state. In particular, a movable photosensitive member supporting means such as a rotating drum having an electrophotographic photosensitive member on its surface and a developing device (and, in many cases, after a toner image on the photosensitive member is transferred to a transfer member such as ordinary paper) A cleaning unit for removing residual toner from the photoreceptor) is mounted on a common unit frame to constitute a replaceable so-called process unit, and the process unit is detachably mounted on a housing of the image forming machine. In many types of image generating apparatuses, a developing apparatus adopting the above-described toner pre-filling method is often used.

Therefore, it is important that the following requirements are satisfied in the developing device employing the above-described toner pre-filling method. That is, it is important that the toner is securely sealed in the toner storage chamber without being discharged from the toner discharge opening until the toner is actually installed in the use place and the use is started. If toner leaks from the toner discharge opening during transportation or the like, the leaked toner contaminates the photoconductor or various elements disposed around the photoconductor. On the other hand,
After the start of use, it is important that toner is supplied from the toner storage chamber to the developing chamber through the toner discharge opening as required.

In order to satisfy the above requirements, in a conventional developing device employing the above-described toner pre-filling method, the toner discharge opening of the toner storage chamber is sealed with an appropriate seal member, and the seal member is used at the start of use. It is removed so that the toner discharge opening is opened.

<Problems of the Related Art> However, the conventional developing device has the following problems. Toner is inevitably attached to a portion of the seal member that is exposed to the toner storage chamber through the toner discharge opening. Therefore, when the seal member is removed, the toner adhered to the seal member often adheres to the hand or clothes of the worker or scatters around.

<Object of the Invention> The present invention has been made in view of the above-mentioned facts, and its main purpose is to securely seal the toner discharge opening until it is installed at the place of use and to start use, and the toner from the toner storage chamber Can be reliably prevented, and at the start of use, the toner discharge opening is opened to remove toner from the toner storage chamber without fear of attaching toner to the hands or clothes of the worker or causing the toner to scatter around. Supply of the toner to the developing chamber can be enabled. It is to provide an improved developing device for an image generator.

<Summary of the Invention> According to the present invention, a developing chamber, an application unit disposed in the developing chamber for applying a toner to an electrostatic latent image to be developed, and a developing device are communicated with the developing chamber through a toner discharge opening. And a toner supply roller rotatably disposed in the toner discharge opening. The toner supply roller is made of an elastically deformable material. A large-diameter portion formed at a distance from the rotation center axis to the peripheral surface larger than other portions, and when not in use, the large-diameter portion is positioned at a sealing angle position located at the toner discharge opening; A developing device is provided, wherein a peripheral surface portion of a diameter portion is pressed against the toner discharge opening, and the toner discharge opening is hermetically sealed by slightly elastically deforming the large diameter portion.

<Preferred Specific Embodiment of the Invention> Hereinafter, a more detailed description will be given with reference to the accompanying drawings.

Overview of Electrostatic Copying Machine FIG. 1 schematically shows an electrostatic copying machine provided with a specific example of a developing device configured according to the present invention.

The illustrated copying machine includes a substantially straight three-dimensional housing indicated by reference numeral 2 as a whole. The housing 2 has a support structure defined by a lower support frame 4 and an upper support frame 6. The lower left end of the support frame 6 is pivotally connected to the lower support frame 4 via a shaft 8, and pivots between a closed position indicated by a solid line and an open position indicated by a two-dot chain line. Can be done.

On the upper surface of the housing 2, that is, on the upper surface of the upper support frame 6, a document placing means 10 is mounted so as to be reciprocally movable in the left-right direction. The original placing means 10 includes a transparent plate 12 on which an original to be copied is placed, and an openable / closable original cover 14 for covering the transparent plate 12 and the original placed thereon.
And

A so-called process unit, generally denoted by reference numeral 16, which is positioned substantially at the center of the housing 2, is detachably mounted on the support frame 6. More specifically, a pair of support rails 18 and 20 extending in a direction perpendicular to the paper are fixed to the upper support frame 6 at intervals in the left-right direction.
On the other hand, the process unit 16 has a unit frame 22,
On both left and right sides of the unit frame 22, supported rail portions 24 and 26 extending in a direction perpendicular to the paper surface are formed. The supported rail portions 24 and 26 of the unit frame 22 are engaged with the support rails 18 and 20 of the upper support frame 6, respectively, and the unit frame 22 is slid in the front-rear direction, that is, in the direction perpendicular to the plane of FIG. As a result, the process unit 16 is attached to and detached from the upper support frame 6. At a substantially central portion of the unit frame 22, a rotary drum 28 is rotatably mounted. An appropriate electrophotographic photosensitive member is disposed on the peripheral surface of the rotating drum 28. The unit frame 22 further includes a charging corona discharger 32 around a rotary drum 28 that is driven to rotate in a direction indicated by an arrow 30 in the rotation direction, and a developing device generally denoted by reference numeral 34. Is also mounted. The cleaning device 36 includes an elastic blade 38 that contacts the peripheral surface of the rotary drum 28, a toner feeding roller 42 that is driven to rotate in a direction indicated by an arrow 40, and a toner storage chamber 44. The developing device 34 will be described in further detail later.

The upper support frame 6 further includes the process unit 16.
The illumination lamp 46, the reflection plate 48, and the optical system 50, which are located above, are also mounted. The optical system 50 is composed of a number of elongated optical elements extending in the vertical direction (for example, a rod-shaped lens sold by Nippon Sheet Glass Co., Ltd. under the trade name "Selfoc Microlens"). The light from the irradiation lamp 46 irradiates the original placed thereon through the transparent plate 12 as shown by a dashed line, and the reflected light from the original is formed on the optical system 50 and the upper wall 52 of the unit frame 22. The rotating drum 28 in the exposure area 56 through the exposed opening 54
Is projected on the surrounding surface. A part of the light from the irradiation lamp 46 also passes through an opening 58 formed on the lower surface of the reflection plate 48 and a charge eliminating light opening 60 formed on the upper wall 52 of the unit frame 22, as indicated by a dashed line. The light is projected on the peripheral surface of the rotating drum 28 in the charge removal area 62.

In a substantially central portion of the lower support frame 4, a transfer corona discharger facing the peripheral surface of the rotary drum 28 in the transfer area 64.
A transfer neutralizer 68 is disposed adjacent to and downstream of the transfer corona discharger 66.

Further, at the right end of the lower support frame 4, a copy paper supply means indicated by reference numeral 72 is provided.
A copy paper tray 74 is disposed at the left end of the tray. Further, between the copy paper supply means 72 and the copy paper tray 74, the entirety for conveying the copy paper through the transfer area 64 is designated by numeral 76.
Is provided. Copy paper supply means
72 includes a copy paper table 78 and a copy paper delivery roller 80 disposed above the downstream end of the copy paper table 78. The copy paper delivery roller 80 is selectively moved up and down and
It is driven to rotate in the direction indicated by 82. Copy paper supply means
72 is further provided downstream of the copy paper stand 78 and has an arrow
A copy paper feed roller 86 driven to rotate in the direction indicated by 84,
And a copy paper separating means 88 disposed below. The copy paper separating means 88 includes a support member 92 rotatably mounted by a pin 90 and a separation member 94 formed on a top surface of the support member 92 and formed of a high friction material such as synthetic rubber. Have. The support member 92 is elastically biased clockwise by a suitable spring means (not shown) so that the separating member 94 is elastically pressed against the copy paper feed roller 86. Copy paper supply means 72 as described above
In, a layer of sheet-like copy paper of the appropriate dimensions is manually inserted onto the copy paper table 78. Each time the copy paper delivery roller 80 is lowered and rotated at the arrow 82, the upper copy paper in the copy paper layer is sequentially delivered, and the copy paper is further advanced by the copy paper supply roller 86. The separating member 94 prevents the copy paper other than the top copy paper from being advanced by the copy paper feed roller 86 when two or more copy papers are fed at one time by the copy paper feed roller 80. Thus, the copy paper is supplied to the copy paper transport system 76 one by one. Copy paper transport system 76
Is a guide plate pair 96, a transport roller pair 100 that is driven to rotate in the direction indicated by arrow 98, guide plates 102 and 104, a transport belt mechanism 108 that is driven to rotate in the direction indicated by arrow 106, and rotates in the direction indicated by arrow 110. Driven fixing roller pair 112, guide plate pair 11
4, and a discharge roller pair 118 which is driven to rotate in the direction indicated by arrow 116. Appropriate heating means 122 is provided in the upper heating roller 120 of the heating and fixing roller pair 112. The upper heating roller 120 is provided with a peeling member 124 for preventing the wrapping of the copy paper.

In the electrostatic copying machine as described above, the rotating drum 28
Is driven to rotate in the direction indicated by the arrow 30, the charging corona discharger 32 charges the photoreceptor substantially uniformly to a specific polarity on the rotating drum 28, and then in the exposure area 56, on the transparent plate 12. The document image is scanned and exposed on the photoconductor, and an electrostatic latent image corresponding to the document image is thus formed on the photoconductor. At the time of the above-mentioned scanning exposure, the document placing means 10 is moved by, for example, scanning exposure from a scanning exposure start position shown by a two-dot chain line 10A to a scanning exposure end position shown by a two-dot chain line 10B. Thereafter, the electrostatic latent image on the photoreceptor is transferred to the developing device 34.
Is developed into a toner image. Next, the copy paper supplied from the copy paper supply means 72 and conveyed by the copy paper conveyance means 76 is brought into close contact with the peripheral surface of the rotating drum 28 in the transfer area 64, and is transferred onto the photoreceptor by the action of the transfer corona discharger 66. The toner image is transferred onto the copy paper. Thereafter, the copy paper is peeled from the rotating drum 28 by the action of the static eliminator 68. The peeled copy paper is conveyed through a pair of heat fixing rollers 112, during which the toner image on the copy paper is heated and fixed, and then discharged onto the copy paper tray 74. On the other hand, the rotating drum 28 is further rotated, and the toner remaining on the photoconductor after transfer is removed from the photoconductor by the action of the elastic blade 38 of the cleaning device 36. The removed toner is
The toner is fed into the toner collecting chamber 44 by the toner feeding roller 42 and collected there. Next, in the neutralization area 62, the photosensitive member is irradiated with static elimination light, and residual charges on the photosensitive member are eliminated.

Thus, the electrostatic copying machine as described above is merely an example of an image generator to which a specific example of the developing device configured according to the present invention is applied, and therefore, as described above, Details of the configuration and operation of the electrostatic copying machine other than the developing device will not be described in the present invention.

Configuration of Developing Apparatus The description will be further continued with reference to FIG. 2 together with FIG.
The unit frame 22 is in the front-back direction (that is, the direction perpendicular to the paper surface).
Has a front wall and a rear wall (not shown) arranged at predetermined intervals. The illustrated developing device 34 includes end walls 126 (FIG. 4) and 128 (FIG. 1, FIG. 1) disposed between the front and rear walls.
FIG. 4). Between the end walls 126 and 128, various walls 130, 132, 134, 136, 138, 140 extending in the front-back direction and
142 is provided, and the developing device 34 is provided with the walls 130, 132, 1
Three rooms partitioned by 34,136,138,140 and 142,
That is, a developing chamber 144, a start developer storage chamber 146, and a toner storage chamber 148 are provided. The walls 130, 132, 134, 136, 138, 140 and 142 can be formed integrally with each other.

The left side of the developing chamber 144 facing the rotating drum 28 is opened. In the developing chamber 144, the application unit 150,
A stirring means 152 and a partition plate 154 are provided. The application means 150 comprises a stationary permanent magnet 160 having a cylindrical sleeve 158 rotatably driven in the direction indicated by the arrow 156 and a plurality of magnetic poles disposed in the sleeve 158 and circumferentially spaced. And can be composed of The stirring means 152 can be configured by a spiral blade or the like that is driven to rotate in the direction indicated by the arrow 162. On a wall 142 that defines a left upper surface wall of the developing chamber 144, a so-called ear-cutting means 164 protruding toward the sleeve 158 of the applying means 150 is formed. Further, on the wall 142, a toner density detector 166 located above the ear cutting means 164 is provided. The detector 166, which may be of a known type, has a detection surface exposed in the developing chamber 144.

The start developer storage chamber 146 is filled in advance with a start developer (not shown) composed of a carrier and a toner. Such a start developer storage chamber 146
It is important that the developing device 34 is securely sealed until the time of actual use, so that toner and / or carrier do not leak from the start developer accommodating chamber 146. On the other hand, as described later, when the use of the developing device 34 is started, it is necessary to supply the start developer housed in the start developer housing chamber 146 to the developing chamber 144, One or a plurality of openings (not shown), which are openably sealed, are formed in a wall 138 forming a partition between the chamber 144 and the start developer accommodating chamber 146.
Are formed. A sealing means (not shown) for opening and closing the opening is disclosed in Japanese Patent Application No. 61-80938 (name of the device: developing device for image forming machine) filed by the present applicant. It is convenient that the configuration is as disclosed in the drawings, and the description thereof is left to the specification and drawings of the above-mentioned utility model registration application, and is omitted in this specification.

The toner is filled in the toner storage chamber 148 in advance. An elongated toner discharge opening 168 extending in the front-rear direction is formed at a lower end portion of a wall 136 forming a partition between the toner storage chamber 148 and the developing chamber 144. In a specific example, two toner discharge openings 168 are provided in the front-rear direction. The toner storage chamber 148 is communicated with the developing chamber 144 through the toner discharge opening 168. Except for the toner discharge opening 168, the toner storage chamber 148 can be completely sealed. The toner discharge opening 168 has an arrow 184
Toner supply roller selectively driven to rotate in the direction shown by
172 are provided. The toner supply roller 172 has an arrow 184
The toner can be supplied from the toner storage chamber 148 to the developing chamber 144 accordingly. The toner supply roller 172 and components related thereto will be further described later.

In the developing device 34 as described above, as will be apparent from the following description, after the developing device 34 is actually used, the toner storage chamber is rotated according to the rotation of the toner supply roller 172 in the direction indicated by the arrow 184. It is important that the toner is reliably supplied from the 148 to the developing chamber 144. On the other hand, before the developing device 34 is actually used, for example, when the process unit 16 is transported or when the entire electrostatic copying machine to which the process unit 16 is mounted is transported, the toner chamber 1
It is important to ensure that toner does not leak to 44. When the toner leaks from the toner storage chamber 148 to the developing chamber 144, as will be easily understood, the toner is supplied to the rotary drum 28 or a charging corona discharge device disposed around the rotary drum 28.
They adhere to elements such as 32 and contaminate them.

In the developing device 34 configured according to the present invention, the toner supply roller 172 disposed at the toner discharge opening 168 is used.
It is important that the toner discharge opening 168 is sealed by elastic deformation of the toner supply roller 172. Referring mainly to FIGS. 2 and 3, in a specific example, the toner storage chamber 148
The toner supply roller 172 has two cylindrical rollers 174 corresponding to each of the toner discharge openings 168 provided in
Two rollers 174 are mounted on the shaft member 176 at predetermined intervals. Both ends 178a and 178b of the shaft member 176 are rotatably mounted on the end walls 126 and 128, and the shaft member 176 (constituting the shaft of the toner supply roller 172) is shown in FIGS.
As can be understood from the drawing, a rotation center axis extending in the front-rear direction of the toner supply roller 172 is configured. Each roller 174 is preferably formed from a relatively soft material such as sponge rubber. Each of the rollers 174 has a size somewhat larger than the size of each toner discharge opening 168, as shown in FIG. 4, and closes the corresponding toner discharge opening 168. A substantially upper half of the peripheral surface of each roller 174 is located on the toner storage chamber 148 side, and a substantially lower half of the peripheral surface of each roller 174 is located on the developing chamber 144 side.

In such a specific example, it is important that the toner supply roller 172 has a large diameter portion whose distance from the rotation center axis to the peripheral surface is larger than other portions. 2 to 5, in the illustrated specific example, the shaft member 176 is
The roller 174 is arranged eccentrically to one side (the upper side in FIGS. 4 and 5) from the center axis of the roller 174 itself. Therefore, the other side of the roller 174 (the lower side in FIGS. 4 and 5) has the longest distance from the rotation center axis (formed by the shaft member 176) to the peripheral surface as compared with the other parts. The other side portion constitutes the large diameter portion described above. Shaft member
Instead of disposing the 176 eccentrically from the center axis of the roller 174 itself, a projection extending in the axial direction may be provided on the peripheral surface of the roller 174, and the projection may constitute a large diameter portion. In the toner supply roller 172, the sealing angle position (the angle position shown in FIGS. 2 and 4)
, The other side of the roller 174 (the portion forming the large diameter portion) is positioned at the toner discharge opening 168. In this way, as clearly shown in FIGS. 2 and 4, the other side of the peripheral surface of each roller 174 has a large distance from the rotation center axis to the peripheral surface at the other side. Wall 136
As shown in FIGS. 2 and 4, the roller 174 is pressed against a portion defining the toner discharge opening 168 at the lower end of the roller 174, and the surface of the other side of each roller 174 acts as a portion defining the toner discharge opening 168. It is somewhat elastically deformed. Therefore, when the toner supply roller 172 is at the sealing angle position, the toner discharge opening 168 is completely sealed by the corresponding roller 174.

In a specific example, in relation to the toner supply roller 172,
Further, deflection preventing means is provided. As shown in FIGS. 2 and 3, the deflection preventing means shown in the drawing comprises a substantially triangular deflection preventing member 182 provided with a receiving recess 180. The deflection preventing member 182 is provided at the intermediate portion 178c of the shaft member 176 of the toner supply roller 172.
180 is operatively fixed to the walls 132 and 136, and serves mainly to prevent the toner supply roller 172 from bending when the toner supply roller 172 is at the sealing angle position. That is, when the toner supply roller 172 is at the sealing angle position, the other side of the roller 174 is pressed against the portion defining the toner discharge opening 168, so that the toner supply roller 172 is separated from the toner discharge opening 168. And the amount of deflection is substantially central in the axial direction (in the specific example, the middle portion).
178c) is substantially the maximum. Accordingly, there is a possibility that the toner discharge opening 168 may be somewhat released due to such bending, and therefore, the bending prevention member 1 may be used to reliably prevent the toner discharge opening 168 from being released due to the bending.
82 is attached. As will be easily understood from the above description, when the above-described bending of the toner supply roller 172 is substantially absent (for example, when the length of the toner supply roller 172 in the axial direction is short, etc.), the above-described bending prevention member is used. 182
Can be omitted, and in such a case, as can be easily understood, a single toner discharge opening 168 can be used. If desired, a lock means for releasably locking the toner supply roller 172 at the above-mentioned sealing angle position may be provided.

Operation and Effect of Developing Device The operation and effect of the developing device 34 described above will be described.
It is as follows.

By the time the developing device 34 is actually used, as described above, the developing chamber 144 and the start developer accommodating chamber 146 are provided.
An opening (not shown) formed in a wall 138 which forms a partition wall is sealed by a sealing means (not shown) which can be opened. In addition, the toner supply roller 172
Are located in the sealing angle position. When in the above-mentioned sealing angle position, the roller 1
The other side (large-diameter portion) of 74 is somewhat elastically deformed by the portion defining the toner discharge opening 168, thereby ensuring that the toner discharge opening 168 is tightly sealed. As can be easily understood by referring to the drawings, the roller 174 reliably prevents the toner from leaking from the toner storage chamber 148 through the toner discharge opening 168 to the developing chamber 144. Thus, when the process unit 16 is transported or when the entire electrostatic copying machine to which the process unit 16 is mounted is transported, the start developer is reliably prevented from leaking from the start developer storage chamber 146 to the developing chamber 144. In addition, the leakage of the toner from the toner storage chamber 148 to the developing chamber 144 is reliably prevented.

When the use of the developing device 34 is started, an opening (not shown) formed in a wall 138 that forms a partition between the developing chamber 144 and the start developer accommodating chamber 146 is opened, and thus the start developer is opened. The start developer stored in the storage chamber 146 (the start developer is composed of carrier and toner) is dropped into the development chamber 144. Then, developing room 1
The start developer is supplied to 44, and the electrostatic latent image can be developed by the developing device. When performing the development, the stirring means 152 is rotated in the direction indicated by the arrow 162 in the developing chamber 144, whereby the developer is stirred and the toner is charged to a predetermined polarity. The sleeve 158 in the application means 150 is rotated in the direction shown by the arrow 156, and the developer retained on the surface of the sleeve 158 by the magnetic attraction force of the magnet 160 disposed in the sleeve 158 is released.
Are transported in the direction indicated by the arrow 156 in accordance with the rotation of. The excess of the developer held on the surface of the sleeve 158 is removed by the action of the
The amount of developer on the surface of 158 is adjusted. Thereafter, the developer on the surface of the sleeve 158 is brought into contact with the photoreceptor disposed on the surface of the rotating drum 28, and the toner in the developer corresponding to the electrostatic latent image on the photoreceptor is removed. Given above,
Thus, the electrostatic latent image is developed into a toner image. Hot cutting means 16
The developer removed from the surface of the sleeve 158 by the action of 4 is caused to flow upward, then to the right on the partition plate 154, and to flow down onto the stirring means 152. The toner concentration detector 166 detects the toner concentration in the developer. When the toner is consumed and the toner concentration is reduced by performing the development, the detector 166 generates a signal, and accordingly, the toner supply roller 172 is rotated in the direction shown by the arrow 184 (FIG. 2). Then, the toner supply roller 172
Is rotated from the above sealing angle position to automatically open the toner discharge opening 168, and thus the toner is supplied from the toner storage chamber 148 to the developing chamber 144 through the toner discharge opening 168 by the action of the toner supply roller 172 and therefore the roller 174. Is done.
In this specific example, the distance from the rotation center axis to the peripheral surface is relatively short on one side of the roller 174, while the distance from the rotation center axis to the peripheral surface is relatively long on the other side of the roller 174. The above-described toner developing chamber
The supply to 144 is performed mainly when the one side of the roller 174 passes through the toner discharge opening 168.

<Effects of the Invention> According to the present invention, the toner supply roller is formed of an elastically deformable material, has a large-diameter portion in which the distance from the rotation center axis to the peripheral surface is larger than other portions, and is not used. Sometimes, the large-diameter portion is positioned at a sealing angle position located at the toner discharge opening, and the peripheral surface of the large-diameter portion is pressed against the toner discharge opening, and the large-diameter portion is somewhat elastically deformed, thereby causing toner discharge. Since the opening is configured to be sealed, it is possible to reliably prevent the toner from leaking from the toner storage chamber to the developing chamber when the copying machine is not in use, such as during transportation.

Further, according to the present invention, when the toner supply roller is rotationally driven during toner supply, the driving torque is reduced except when the large diameter portion of the toner supply roller is located at the sealing angle position. Can be minimized.

[Brief description of the drawings]

FIG. 1 is a simplified sectional view showing an electrostatic copying machine provided with a specific example of a developing device constituted according to the present invention. FIG. 2 is a sectional view showing the developing device shown in FIG. FIG. 3 is an exploded perspective view showing the toner supply roller of the developing device of FIG. 2 and its vicinity in an exploded manner. FIG. 4 is a sectional view showing a toner supply roller of the developing device of FIG. 2 and its vicinity. FIG. 5 is a side view showing a toner supply roller in the developing device of FIG. 2 Housing 4 Lower support frame 6 Upper support frame 16 Process unit 22 Unit frame 34 Developing device 144 Developing chamber 146 Start developer container 150 150 Toner Storage chamber 168: toner discharge opening 172: toner supply roller 174: roller

Claims (3)

(57) [Claims] A developing chamber for applying toner to an electrostatic latent image to be developed; an application means disposed in the developing chamber; and a toner storage chamber communicated with the developing chamber through a toner discharge opening. And a toner supply roller rotatably disposed at the toner discharge opening, wherein the toner supply roller is formed of an elastically deformable material and has a rotation center axis. Has a large diameter portion whose distance from the peripheral surface is larger than other portions, and when not in use, the large diameter portion is positioned at the sealing angle position located at the toner discharge opening, and the peripheral surface portion of the large diameter portion Wherein the large diameter portion is somewhat elastically deformed by being pressed against the toner discharge opening to seal the toner discharge opening. 2. The toner supply roller is composed of a cylindrical roller, and the center axis of rotation of the toner supply roller is slightly eccentric to one side from the center axis of the roller itself, and the other side of the roller is connected to the other side of the roller. Claim 1 comprising a large diameter portion
6. The developing device according to claim 1. 3. A flexure preventing means for preventing flexure of the toner supply roller, which is generated when the toner supply roller is at the sealing angle position, is provided at an axially intermediate portion of the toner supply roller. 3. The developing device according to claim 1 or 2.