JPH041560Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a dry phenomenon device used in electrophotographic devices and electrostatic recording devices such as copying machines, printers, and facsimile machines.

``Prior art'' Conventionally, high-resistance toner is charged with a polarity opposite to that of the electrostatic latent image, so that the toner is uniformly adhered to the surface of a conductive developing roller, and the roller is rotated close to the surface of the photoreceptor. However, dry type development devices for forming a toner image on the electrostatic latent image portion carried on the surface of the photoreceptor are already known, and typical examples include a touch-down development method and a pressure development method.

"Technical problem to be solved by the invention" In such a developing method, after the toner is attached to the electrostatic latent image area, the charged toner remaining on the surface of the developing roller is not wiped off before the next step. When charging is performed, toner is further superimposed and adhered to the portion of the surface of the developing roller where residual toner has adhered, causing uneven adhesion of toner, resulting in uneven image and uneven image density during development. , it is difficult to obtain clear and stable images.

In order to prevent such a drawback, it is sufficient to sweep off the residual toner by disposing a cleaning member on the surface of the conductive developing roller near the photoreceptor, that is, on the downstream side of the developing position. Since the roller rotates in the opposite direction to the rotation direction of the photoreceptor, if a configuration in which a cleaning member is simply brought into contact with the surface of the developing roller is used, toner will be scattered on the upstream side of the developing roller, that is, on the photoreceptor side, and the developing Excess toner adheres to the visible image area and background area on the surface of the photoreceptor, causing image disturbance and making it impossible to form a clear image.

Furthermore, since the toner remaining on the surface of the developing roller is charged toner, if it is swept away as it is, the toner may aggregate in the toner storage chamber, or the toner may adhere unevenly when reused next time. This may adversely affect image formation.

In view of the drawbacks of the prior art, the present invention reliably sweeps off the residual toner adhering to the surface of the developing roller without scattering the toner on the surface of the photoreceptor after development, and as a result, the surface of the developing roller is It is an object of the present invention to provide a dry type developing device that can always prepare for the next supply of toner in a clean state and can always form stable and highly clear images.

"Technical Means for Solving the Problems" The present invention includes a toner supply roller that guides toner whose layer thickness is regulated by an enclosed magnet assembly toward a photoconductor, and a toner supply roller that is disposed between the supply roller and the photoconductor, The present invention relates to a dry type developing device comprising an electrically conductive developing roller that guides toner carried on the drum to a developing position facing a photoreceptor.

More specifically, the present invention is applied to a dry type developing device in which a developing roller is disposed between a toner supply roller containing a magnet assembly and a photosensitive drum.

The feature of the present invention is that the developing roller is rotatable in contact with the lower circumferential surface of the developing roller along the rotational direction of the developing roller until it contacts the photoconductor or reaches a position facing the supply roller at a nearby position. The present invention is characterized in that a cleaning member is provided, and a group of conductive fibers is provided on the surface layer of the cleaning member.

That is, to summarize, the cleaning member is disposed in contact with the lower circumferential surface of the phenomenon roller downstream of the development position, and a group of conductive fibers is attached to the surface layer of the cleaning member, and more specifically, the cleaning member is made of polyester,
Acrylic, rayon, carbon-containing rayon,
Conductive fibers such as nylon or vinylon are formed into a rotating brush shape around a rotating shaft, or the fibers are wound into a rotating roller shape.

It is characterized by

The surface of the developing roller is coated with a conductive coating layer made of the same kind of material as the toner. Here, "the same kind as the toner 4" refers to the materials constituting the toner 4 described above, such as resin, magnetic powder, and coloring. A material made of a composition containing at least one of the following: a resistance control agent, a resistance control agent, an additive, etc.

The cleaning member is rotated in the opposite direction to the rotating direction of the developing roller and set at a circumferential speed higher than the circumferential speed of the developing roller, that is, the cleaning member sweeps off the toner on the lower circumferential surface of the developing roller toward the supply roller side. The point is that the rotation direction and circumferential speed are set as possible.

We propose a dry developing device featuring the following.

"Effect" According to this technical means, as shown in Figure 3,
Since the cleaning member 50 rotates in the opposite direction to the rotational direction of the developing roller 30 and is set at a higher peripheral speed than the developing roller 30, it can be rotated while rubbing the surface of the developing roller 30 in the direction of the supply roller 40, and as a result, the developing roller The toner 4 remaining on the supply roller 30 is swept off toward the supply roller 40 side.

Since the toner that is swept away at this time is a fine powder on the order of microns, even if the toner is swept off on the upper peripheral surface of the developing roller 30, it simply floats in the air and re-adheres to the developing roller 30. Undesirable.

In contrast, in the present invention, the cleaning member 50
Since the contact surface is located on the lower circumferential surface of the developing roller 30, the fear of re-adhesion can be eliminated.

In addition, this invention does not simply sweep it into the air,
The swept toner adheres to the supply roller 40 because it is swept toward the toner supply roller 40 side, in other words, the supply roller 40 side that includes the magnet assembly 41 and has the ability to carry toner;
Not only can it be recovered, but it can also prevent airborne contamination.

Since the cleaning member 50 is made of a fibrous material, the toner can be reliably captured and swept away. However, if the cleaning member 50 is made of an insulating fibrous material, it will be charged by rubbing against the developing roller 30 and the toner will be swept away. The toner adheres to the surface of the cleaning member 50 and cannot be smoothly swept away.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks by forming the cleaning member 50 from a conductive fiber material.The fact that the cleaning member 50 is formed from a conductive material is advantageous in that during the sweeping process, The charge on the toner 4 can be removed,
It will not cause any problems during the next reuse.

Now, as described above, when the cleaning member 50 and the developing roller 30 are rubbed together through the toner, the residual toner carried on the developing roller 30 is not only disposed between the cleaning member 50 and the developing roller 30.
As a result, the toner is injected with charge due to frictional electrification and is attracted to the developing roller 30 side, making it impossible to sweep it away smoothly.

Therefore, in the present invention, since a conductive coating layer made of the same material as the toner is formed on the surface of the developing roller 30, frictional electrification does not occur due to the rubbing, and the cleaning member 50 can slide more smoothly. In addition, the surface of the developing roller 30 can be kept clean and ready for the next charging, and as a result, the electric field strength between the supply roller 40 and the developing roller 30 is always constant and stable. Image formation becomes possible.

Furthermore, since no electric charge is injected into the toner in either the cleaning member 50 or the developing roller 30, and any residual electric charge is removed, even if the toner is repeatedly charged between the two rollers, the developing roller 30
There is no fluctuation in the amount of toner 4 that adheres to the surface, and stable image formation is possible.

"Embodiments" Hereinafter, embodiments of the present invention will be described in detail by way of example based on the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative positions of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. Not too much.

FIG. 1 shows a schematic configuration of a copying machine to which an embodiment of the present invention is applied, in which 7 is a drum-shaped photoreceptor with a photoconductive layer on its surface, around which are a charging device 8, an exposure device 9, and a developing device. 10, transfer device 11, cleaning device 1
2 etc. are arranged.

In such a copying machine, as is well known, when the photoreceptor 7 rotates clockwise in synchronization with the movement of a document table (not shown), a predetermined charge is first applied by a charging device 8, and then a predetermined charge is applied by an exposure device 9. The electrostatic latent image 7a corresponding to the original image on the original platen is exposed sequentially to the photoreceptor 7.
formed on the surface. This electrostatic latent image 7a is visualized as a toner image by a developing device 10, which will be described in detail later, and reaches a transfer device 11. In the transfer device 11, the toner image is transferred and carried on the transfer paper 13 fed from the paper feeder 14, and then the transfer paper 13 is transferred to the photoreceptor 7.
The image is separated from the image and fixed as a final image in the fixing device 15. On the other hand, the photoreceptor 7 to which the toner image was transferred
After the residual toner 4 is removed by the cleaning device 12, it is ready for the next copying.

Since these copying steps are already well known, detailed explanation will be omitted.

On the other hand, the toner 4 used in the copying machine is a high-resistance magnetic toner having a volume resistivity of at least 10 ¹³ Ωcm or more, such as styrene-acrylic resin, magnetite (magnetic powder), carbon black (which also serves as a coloring agent). Resistance control agent), silica (additive), etc. are kneaded and heated in an appropriate blending ratio, then pulverized and classified to have an average particle size of 15 to 25 μm.

FIGS. 2 and 3 show a developing device 10 as an embodiment of the present invention used in the copying machine, and a frame 20
, a developing roller 30 , a supply roller 40 , a cleaning member 50 , and a height regulating member 60 .

The frame body 20 is arranged along the circumferential direction of the photoreceptor 7 over almost the entire length in the longitudinal direction of the photoreceptor 7,
It consists of a cartridge mounting part 21 formed at the top, and a toner storage chamber 22 which is continuous with the cartridge mounting part 21 and has an opening on the side facing the photoreceptor 7.

A toner replenishment cartridge 23 is detachably attached to the cartridge attachment part 21, and by peeling off the sealing member 24 stuck to the bottom surface of the cartridge 23 using a peeling means (not shown), the toner in the cartridge 23 can be removed. flows down along the frame bottom plate 25 and is replenished into the storage chamber 22.

Inside the toner storage chamber 22, the developing roller 30, the supply roller 40, and the cleaning member 50 are arranged parallel to the rotation axis of the photoreceptor 7, respectively, and a height regulating member 60 is arranged above the supply roller 40 so that the lower end 6
1 is disposed close to the outer peripheral surface of the supply roller 40.

The phenomenon roller 30 is composed of a rotating body 31 made of conductive rubber and a conductive coating layer 32 applied to the outer circumferential surface of the rotating body 31, and is arranged so that the outer circumferential surface is in contact with the outer circumferential surface of the photoreceptor 7. At the same time, the developing roller 30 rotates in contact with the rotation of the photoreceptor 7 via a gear (not shown) or the like, that is, the developing roller 30 has the same circumferential speed as the photoreceptor 7 and rotates in the opposite direction. It is configured as follows. Note that the contact with the outer circumferential surface of the photoreceptor 7 may be either contact or elastic pressure contact. The rotating body 31 formed of the conductive rubber has a volume resistance value of 10 as an electrical resistance.
The resistance to be used is ¹¹ Ωcm or less, preferably in the range of 10 ⁵ to ^{10 9} Ωcm.

Further, since the developing roller 30 is grounded and is electrically conductive as described above, an electric field can be formed between it and the supply roller 40 as described later.

Next, to explain the coat layer 32 in detail, the material of the coat layer 32 is the same as that of the toner 4 in order to reduce the physical adhesive resistance between the two when the coat layer 32 comes into contact with the toner 4. In addition, in order to smoothly achieve the electric field formation, the volume resistance value is 10 ¹¹ Ω similarly to the rotating body 31.
cm or less, preferably in the range of 10 ⁵ to 10 ⁹ Ωcm.

Here, "the same kind as the toner 4" means that the toner 4 is made of a composition material containing at least the same types of the materials constituting the toner 4, such as resin, magnetic powder, colorant, resistance control agent, and additives. refers to something that has been done.

In this embodiment, only the blending ratio of the resistance control agent such as magnetite or carbon black in the materials constituting the toner 4 was changed (increased) to control the volume resistivity within the range of 10 ⁵ to ^{10 9} Ωcm. It is formed by

As the thickness of the coating layer 32 increases, the conductive resistance increases, which is not preferable for toner adhesion and electric field formation as described later. The film is formed to be about 3 to 5 times thicker.

Further, the coating layer 32 may be applied so as to absorb the unevenness on the surface of the rotating body 31 formed of the conductive rubber so that the surface of the developing roller 30 becomes a smooth surface. The coating may be applied by brush coating, dipping or other known coating methods, and may also be baked or electron beam hardened to prevent peeling from the surface of the rotating body 31.

A supply roller 40 is disposed on the upstream side of the photoreceptor 7 contact side of the developing roller 30, that is, on the entrance side of the toner 4 storage chamber, with its outer circumferential surface being close to the outer circumferential surface of the developing roller 30.

The supply roller 40 includes a cylindrical magnet assembly 41 having a large number of magnetic poles formed on its surface, and a conductive sleeve made of a conductive non-magnetic material such as aluminum and arranged concentrically around the assembly 41. 42, the magnet assembly 41 and the conductive sleeve 4
By relatively rotating between the two, the toner 4 (magnetic brush 4a) carried in the form of a spike on the conductive sleeve 42 is conveyed to the developing roller 30 side. Here, "relatively rotating" means that the magnet assembly 41 and/or the conductive sleeve 42 are rotated so that a relative speed is generated between the magnet assembly 41 and the conductive sleeve 42. This refers to the case where there is.

Next, the configuration of the supply roller 40 will be explained in more detail.The supply roller 40 is connected to the developing roller 30 from a supply roller proximity point (hereinafter referred to as a supply device) to a contact point of the photoreceptor 7 (hereinafter referred to as a development position). The peripheral surface length α is the electrostatic latent image 7 of the photoreceptor 7
The length β from the exposure point forming a to the developing position is greater than β, and the facing distance between the supply roller 40 and the developing roller 30 is 0.3 mm.
It is set to about.

A modulated AC or DC voltage applying means 43 is electrically contacted with the supply roller 40, and a DC voltage having a polarity opposite to that of the electrostatic charge formed on the surface of the photoreceptor 7 by the voltage applying means 43 is electrically connected to the supply roller 40. is applied to the supply roller 40 to generate an electric field of a predetermined strength near the supply position between the conductive developing rollers 30. Further, since the voltage applying means 43 is configured to be voltage controllable, both the rollers 30, 40
The electric field strength between the two can be freely controlled. Further, a control circuit 44 is interposed between the voltage application means 43 and the roller 40, and the voltage application means 43 is turned off at the same time or immediately after the exposure process by the exposure device 9 is completed.

Note that the voltage applying means 43 may be brought into contact with the developing roller 30 side, contrary to this embodiment, but when a DC voltage is applied to the developing roller 30 side, the photoreceptor 7
A potential difference also occurs between the surface and the developing roller 30, and for example, if a DC voltage of opposite polarity to the electrostatic charge is applied, the toner 4 will also adhere to the background area where the electrostatic latent image 7a is not formed (fogging). )do. However, application of a moderate DC voltage may be helpful in removing fog.

The cleaning member 50 is located on the downstream side of the developing position of the developing roller 30, and conductive fibers such as polyester, acrylic, rayon, carbon-containing rayon, nylon, vinylon, etc. are formed into a rotating brush shape around a rotating shaft, or the cleaning member 50 is arranged so that the conductive fibers are formed into a rotating brush shape around a rotating shaft. It is wound to form a rotating roller, and its outer peripheral surface is in contact with the surface of the developing roller 30 between the downstream side of the developing position of the developing roller 30 with the photoreceptor 7 and the supplying position of the supply roller 40. Place it in

The rotation direction and peripheral speed of the cleaning member 50 are set so that the toner 4 remaining on the developing roller 30 is not swept off toward the photoconductor 7 but only toward the supply roller 40. are doing. Specifically, the developing roller 30 is rotated in a direction opposite to the rotating direction of the developing roller 30, and its circumferential speed is configured to be greater than the circumferential speed of the developing roller 30.

The brush height regulating member 60 has a blade shape, and its tip is disposed close to the outer peripheral surface of the supply roller 40 on the upstream side of the supply position, so that the brush height of the magnetic brush 4a can be regulated to a predetermined height.

Next, the operation of the present invention with such a configuration will be explained.

First, when the copying machine starts, as the photoreceptor 7 rotates, the developing roller 30, the supply roller 40,
The cleaning members 50 and 50 are rotated in predetermined rotational directions, and a DC voltage is applied to the supply roller 40, and development is performed in the following order.

That is, first, the toner 4 staying in the storage chamber 22 is carried in the shape of a spike (magnetic brush 4a) on the conductive sleeve 42 by the magnetic attraction force of the magnet assembly 41, and then the toner 4 is held in the shape of a spike (magnetic brush 4a) by the magnet assembly 41 and conductive. The magnetic brush 4a is conveyed to the developing roller 30 side by the relative rotation between the magnetic sleeves 42, and while the brush height of the magnetic brush 4a is regulated by the brush height regulating member 60, only an appropriate amount of toner 4 is delivered to the supply position between the developing rollers 30. approach.

A DC voltage having a polarity opposite to that of the electrostatic charge is applied to the supply roller 40, and a conductive developing roller 3 is applied to the supply roller 40.
0 is grounded, an electric field corresponding to the DC voltage is formed between the rollers 30 and 40. On the other hand, since the rollers 30 and 40 are rotating in opposite directions, the rollers 30 and 40 There is a considerable relative rotational speed between the rollers 30 and 40, and therefore the toner 4 guided to the supply position is formed between the rollers 30 and 40 while being rubbed between the rollers 30 and 40. A charge of opposite polarity to the electrostatic charge corresponding to the electric field strength is applied, and a desired amount of toner 4 is transferred to the developing roller 30.
Electrostatic charge adheres to the entire outer circumferential surface of the The toner 4 adhering to the developing roller 30 is conveyed to the photoreceptor 7 side by the rotation of the roller 30 and guided to the developing position.

The amount of toner attached to the developing roller 30, that is, the amount of toner conveyed to the developing position on the photoreceptor 7 side is as follows:
Since it can be freely controlled by changing the DC voltage applied to the supply roller 40, the electrostatic latent image formed on the surface of the photoreceptor 7 can be controlled depending on whether it is an area image or a line image. Even when adjusting the copy density of the latent image area, by manually or automatically changing the DC voltage, it is possible to easily adjust the copy density and select the developing effect depending on the type of image area.

Next, since the toner 4 guided to the development position is charged with a polarity opposite to the electrostatic charge, it comes into contact with the electrostatic latent image 7a on the surface of the photoreceptor 7, thereby causing the electrostatic latent image 7a to come into contact with the electrostatic latent image 7a.
It is attracted to part a and a visible image is formed.

At this time, since the photoreceptor 7 and the developing roller 30 are rotating at the same circumferential speed while being in rolling contact with each other, the toner 4 can be developed without being rubbed against the photoreceptor 7. This is a drawback of conventional one-component development systems. It is possible to obtain extremely clear images without image disturbances (shifts or blurring) caused by mechanical rubbing.

In particular, in this embodiment, since the surface layer of the developing roller 30 is formed of a conductive rubber-like rotating body 31 with the coating layer 32 in between, the developing roller 30 is pressed against the surface of the photoreceptor 7 (elastically The developing efficiency is further improved.

Further, the development is not performed by applying an electric charge by mechanical friction as in the conventional one-component development method, but by applying an electric charge to the toner 4 forcibly charged at the supply position between the supply roller 40 and the developing roller 30. Photoreceptor 7
The electrostatic latent image area is electrically attracted and
Because it is attached, the development efficiency is extremely high.

For example, print density indicated by reflected optical density is
In order to increase the voltage to 1.4 or higher, the surface potential of the photoreceptor 7 must be set to 1000 V in the conventionally known one-component development method.
However, in this example, even if the surface potential of the photoreceptor 7 was lowered to 400V, it was possible to maintain a printing density of 1.4 or more.

Furthermore, in this embodiment, the developing roller 30
The rotating body 31 made of conductive rubber and the toner 4
Since a low-resistance conductive coating layer 32 made of the same material as the toner 4 is interposed between the toner 4 and the toner 4, the surface energy between the developing roller 30 surface and the toner 4 can be reduced, and the toner 4 can be roller 30
It becomes easy to transfer (suction adhesion) from the photoreceptor 7 to the photoreceptor 7, and the image clarity on the surface of the photoreceptor 7 improves. Furthermore, the presence of the coating layer 32 can prevent the toner 4 from adhering to the surface of the developing roller 30, thereby preventing irregularities in the developing conditions due to time-series resistance changes and variations on the surface of the developing roller 30 caused by the adhesion of the toner 4. It is possible to stabilize the image and prevent image unevenness.

The developing roller 30 that has passed the developing position further rotates and reaches the cleaning member 50. Since the cleaning member 50 rotates while being rubbed against the surface of the developing roller 30, the toner 4 remaining on the developing roller 30 is surely swept away toward the supply roller 40 side. At this time, in this embodiment, since the surface of the developing roller 30 is coated with a conductive coating layer 32 made of the same material as the toner 4, the toner 4 can be more easily swept away.

In this way, the cleaning member 50 is attached to the developing roller 30 between the downstream side of the developing position and the supply position.
Because it is placed in contact with the surface, the developing roller 3
The surface of the roller 0 can always be kept clean in preparation for the next charging, and as a result, the electric field strength between the supply roller 40 and the developing roller 30 is always constant, and charging is repeatedly performed between the rollers 30 and 40. Even if the toner 4 is mixed, the amount of toner 4 adhering to the developing roller 30 does not fluctuate, and stable image formation is possible.

Further, the toner 4 caused by the cleaning member 50
Since the toner 4 is swept only to the supply roller 40 side without being swept to the photoreceptor 7 side, excess toner 4 adheres to the visible image area and background area on the surface of the photoreceptor 7 after development. It is possible to prevent image distortion, etc. without having to do anything.

Further, since the cleaning member 50 is made of a conductive material, it is possible to remove the charge on the toner 4 during the cleaning process, and no problem will occur during the next reuse.

Thereafter, development is carried out while repeating the above-mentioned actions.

At the end of development, the exposure device 9
At the same time or immediately after the exposure process ends, the voltage application means 43 is turned off and the supply roller 40
Stop applying the DC voltage to both rollers 3.
The supply of toner 4 to the developing roller 30 is stopped by cutting off the electric field between 0 and 40, and the developing roller 30 is rotated so that no toner other than toner 4 necessary for development is placed on the developing roller 30. The rearmost electrostatic latent image 7a formed at the end point of the exposure process
After developing the developed visible image, the toner at the rear end adhering to the developing roller 30 is transferred to the developing position, i.e., until the developed visible image is transferred or the final step is performed, i.e., the final image is formed. The toner 4 passes through the contact position of the photoreceptor 7 and is further swept away by the cleaning member 50 on the downstream side, and the machine is stopped with no toner 4 attached to the surface of the developing roller 30.

In this embodiment, the circumferential length α from the supply position of the developing roller 30 to the developing position where it contacts the photoreceptor 7 is longer than the developing position from the exposure point where the electrostatic latent image 7a is formed on the photoreceptor 7. Since the length up to the developing roller 30 is longer than β,
Until the rearmost toner adhering thereon passes through the development position, the rearmost electrostatic latent image 7a formed at the end point of the exposure process passes through the development position,
The above effects are smoothly achieved.

"Effects" As described above, according to the present invention, a rotatable cleaning member is brought into contact with the surface of the developing roller between the downstream side of the photoconductor contacting or proximate position and the toner charging position, and the cleaning member sweeps the surface of the developing roller. The rotating direction and circumferential speed of the cleaning member are set so that the toner that has been removed falls on the side opposite to the photoconductor, so that the toner remaining on the surface of the developing roller can be reliably removed without scattering on the surface of the photoconductor after development. The toner is swept off to the side opposite to the photoreceptor, and as a result, the surface of the developing roller can always be kept clean and ready for the next supply of toner, and stable development and high-definition image formation can be achieved at all times.

In addition, by forming the cleaning member from an electrostatically conductive material, during the sweeping process,
Charged toner can be neutralized, toner aggregation within the toner storage chamber, and uneven toner adhesion during subsequent reuse can be prevented, making it possible to form a good image.

It has various effects such as

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic explanatory diagram of a copying machine to which a phenomenon device according to the present embodiment is applied, FIG. 2 is a sectional view of the phenomenon device, and FIG. FIG. 3 is an explanatory diagram showing the state of adhesion of toner. 4...Toner, 30...Developing roller, 50...
Cleaning parts.

Claims (1)

[Claims for Utility Model Registration] A toner supply roller that guides toner whose layer thickness is regulated by an enclosed magnet assembly toward a photoconductor, and a toner supply roller that is disposed between the supply roller and the photoconductor and that collects the toner carried by the supply roller. In a dry-type developing device comprising a conductive developing roller that is guided to a developing position side facing a photoreceptor, the developing roller is in contact with or close to the photoreceptor up to a position facing the supply roller along the rotation direction of the photoreceptor. a rotatable cleaning member that contacts the lower circumferential surface of the developing roller; and a developing roller whose surface is coated with a conductive coating layer made of the same material as the toner; At the same time, the cleaning member is rotated in the opposite direction to the rotating direction of the developing roller and set at a circumferential speed higher than the circumferential speed of the developing roller, thereby removing the toner on the lower circumferential surface of the developing roller. A dry type developing device, characterized in that the dry type developing device is configured to be able to sweep off toward the supply roller side.