JP2004139123A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of yielding a well-matched and vivid color image by holding a developing gap fixed where a developer carrier and a developer layer for thickness regulating the member are opposed and by keeping density definite. <P>SOLUTION: The developing device is provided at least with the developer carrier 141 opposed to an image forming body 10 to supply developer to the image forming body 10, and the developer layer for thickness regulating member 144 for regulating the layer thickness of the developer held by the developer carrier 141. Furthermore, it is provided with a supporting member 146 which rotatably supports the developer carrier 141 and which is installed to rock in a developing unit housing 140, and a pressing means 150 for pressing the developer carrier 141 to the image forming body 10. The developing device application is not restricted to a color image forming apparatus equipped with a plurality of developing units but it is also applied to a monochrome image forming apparatus equipped with a developing device. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a developing device provided in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile, and in particular, relates to a developer carrying member and a layer thickness regulating member in a color image forming apparatus having a plurality of developing devices. Regarding improvements.

In a conventional developing device, a developer carrier (developing sleeve) that rotates in proximity to a rotating image forming body is disposed. The developer carrier is formed in a hollow cylindrical shape, and is housed in a housing having an opening on a side facing the image forming body. For example, a developing bias voltage in which an AC voltage of 1300 V and 3500 Hz is superimposed on a DC voltage of 200 V is applied to the developer carrier. The developer carrier has a fixed magnet inside, and a two-component developer in which toner particles and magnetic particles (carrier) are mixed is carried on the outer peripheral surface of the developer carrier. In order to regulate the layer thickness of the two-component developer, a layer thickness regulating member is provided. The layer thickness regulating member is provided inside the opposed side wall of the housing at an upstream position in the rotation direction of the developer carrying member, and is installed so as to generate a certain gap between the layer and the outer peripheral surface of the developer carrying member. ing. The layer regulating member generally has a plate shape or a small cylindrical shape.

In a conventional developing device, there is a developing device in which a layer thickness regulating member for regulating a layer thickness of a developer held on a developer carrier is formed of a magnetic material. As a result, the layer thickness of the developer formed on the developer carrier can be increased, and stable developer supply can be achieved. However, when all of the layer thickness regulating member is formed of a magnetic material, the developer to be held by the developer carrier continues to adhere to the layer thickness regulating member, and the developer adheres to the entire region of the layer thickness regulating member. . As described above, when the developer adheres to the entire region of the layer thickness regulating member, the developer leaks out of the developing device and enters the bearing members provided at both ends of the developer carrier to cause a rotation failure, or to cause a development failure. It may flow out of the apparatus and scatter, and the inside of the image forming apparatus may be contaminated by the developer.

Conventionally, a plurality of developing devices are individually pressed against an image forming body by a biasing force of a spring or the like, and a developing roller provided in the developing device is brought into contact with an outer peripheral surface of the image forming body, so that a developing gap is kept constant. However, if a plurality of developing devices are to be accommodated in a limited space, the pressing does not always act in a direction perpendicular to the image forming surface. Therefore, the development gap cannot be kept constant, and stable image formation cannot be maintained. In particular, in a developing device in which a plurality of developing devices are integrally connected, it is extremely difficult to apply a uniform pressing force to all the developing rollers when a conventional pressing is performed.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to maintain a constant development gap in which a developer carrier and a developer layer thickness regulating member face each other, and to stabilize the density. An object of the present invention is to provide a developing device capable of obtaining a harmonious and clear color image.

目的 The object of the present invention can be achieved by the following constitutions.

(Claim 1) In a developing device having at least a developer carrier opposed to an image forming body and supplying a developer to the image forming body, and a developing device casing for housing the developer, the developer carrying body is A developing device comprising: a support member rotatably supported and swingably disposed on the developing device casing; and a pressing unit for pressing the developer carrier against the image forming body.

(Claim 2) The support member is engaged with an engaging portion of the developing device casing or an engaging portion provided on the developing device casing, and is installed to be swingable about the engaging portion as a fulcrum. The developing device according to claim 1, wherein:

(3) The support member supports a developer layer regulating member provided substantially in parallel with a surface of the developer carrying member that carries the developer. The developing device according to claim 1.

(4) The developer carrier has a magnetic field generating means inside the developer carrier, and the developer layer regulating member is provided opposite to a magnetic pole of the magnetic field generating means, and the developer layer regulating member is provided. The developing device according to claim 3, wherein the developing device is made of a magnetic material.

(Claim 5) The image forming body and the developer carrying member have a gap between them, and the gap is maintained by a gap holding member in contact with the image forming body. The developing device according to any one of claims 1 to 4.

(Claim 6) The developing device according to any one of claims 1 to 5, wherein the pressing means is formed of an elastic member.

(Claim 7) The developer carrier and the image forming body have a gap therebetween, and the developer carrier receives supply of electric power for forming an electric field in the gap, and the elastic member includes The developing device according to claim 6, comprising a conductive member that supplies the electric power.

(8) The developing device according to any one of (1) to (5), wherein the pressing unit is a pressing unit that obtains a pressing force by a driving source that rotationally drives the developer carrier. .

(Claim 9) The support member includes a first support member that supports at least one portion of the developer carrier, and a second support member that supports another portion of the developer carrier. The pressing unit presses the first support member by a driving source that rotationally drives the developer carrier so as to press the developer carrier against the image forming body. 2. The image forming apparatus according to claim 1, further comprising a pressing unit, and a second pressing unit configured to press the second support member by an elastic member so as to press the developer carrier against the image forming body. 6. The developing device according to any one of 5.

(Claim 10) The support member includes a first support member that supports at least one portion of the developer carrier, and a second support member that supports another portion of the developer carrier. The first support member and the second support member are independently and swingably installed on the developing device casing, respectively. The developing device according to claim 1.

According to the first aspect of the present invention, there is provided a supporting member rotatably supporting a developer carrier, and a supporting member rotatably mounted on a developing device casing, and a pressing means for pressing the developer carrier against the image forming body. It is about. By the support member and the pressing means, the developer carrier swings and is pressed against the image forming body independently of the developing device, so that the positional relationship of the developer carrier with respect to the image forming body can be accurately set, Stable image formation is possible regardless of the installation state of the developing device. In particular, in a developing device in which a plurality of developing devices are integrally connected, it is effective when it is intended to accurately set the positional relationship of a developer carrier provided in each developing device with respect to an image forming body.

The invention described in claim 2 relates to the fact that the support member swings about an engaging portion of the developing device casing as a fulcrum. If the support member that supports the developer carrier swings about the engagement portion as a fulcrum, the developer carrier can be accurately brought close to the image forming body, and the image forming body of the developer carrier is Can be set accurately. In particular, the positional relationship can be accurately set for a cylindrical image forming body.

The third aspect of the present invention relates to installing a developer leveling member for regulating the amount of developer carried by a developer carrier on the support member. The developer leveling member is also supported by the support member in the same manner as the developer carrier, so that the position of the developer carrier and the developer layer thickness regulating member (developer leveling member) can be maintained even when the support member swings. Since the relationship can be kept constant, the developer carried on the developer carrying member can be always kept constant. Therefore, an image with a constant density can always be formed.

The invention described in claim 4 relates to forming the developer layer thickness regulating member from a magnetic material. In a developing device in which a support member that supports the developer carrier swings, it is difficult to make the amount of the developer carried on the developer carrier constant because the developer carrier swings. Therefore, by forming the developer leveling member that controls the amount of the developer carried on the developer carrier from a magnetic material, the developer is easily attracted to the developer leveling member, and the amount of the developer carried is Since the amount is easily regulated, the amount of the developer can be kept constant, and an image having a constant density can always be formed.

The fifth aspect of the present invention relates to securing a space between the image forming body and the developer carrying member by a gap holding member. In a developing device in which a support member for supporting a developer carrier swings, the developer carrier is brought close to the image forming body by a considerable force by a pressing means, so that the image forming body and the developer carrying body are physically moved. You need to keep your body separated. Therefore, if the gap is maintained by a gap holding member such as a roller, the gap can be accurately maintained, and non-contact development can be favorably performed.

The invention described in claim 6 relates to the pressing means being formed of an elastic member. If the pressing member is formed of an elastic member, and the developer carrying member is brought close to the image forming member, it is possible to most simply and surely maintain the distance between the image forming member and the developer carrying member.

The seventh aspect of the present invention relates to a method of supplying electric power to the developer carrier, wherein the elastic member used for the pressing means is a conductive member, and the electric power is supplied to the member. In this way, if power is supplied to the developer carrying member by the pressing means, it is not necessary to separately install power supply parts, so that the number of parts can be reduced and the number of assembly steps can be reduced. .

The invention described in claim 8 relates to obtaining a force for pressing the developer carrier against the image forming body by a driving source that rotationally drives the developer carrier. By obtaining the pressing force by the driving source, it is not necessary to separately provide a pressing means, so that the number of parts can be reduced and the number of assembling steps can be reduced as in the invention of the seventh aspect.

According to a ninth aspect of the present invention, the first support member that supports one side of the developer carrier is pressed by a pressing unit by a driving source that rotationally drives the developer carrier, and another side of the developer carrier is pressed. The present invention relates to pressing of a second supporting member to be supported by a pressing means using an elastic member. The developer carrier is supported at two places, and by pressing each of the support members, the positional relationship between the image forming body and the developer carrier can be accurately maintained. Moreover, by pressing one of the members by the pressing force of the drive source for driving the developer carrier, there is no need to separately provide a pressing means such as an elastic member, so that the number of parts can be reduced and the number of assembly steps can be reduced. Can also be.

According to a tenth aspect of the present invention, the first support member for supporting one side of the developer carrier and the second support member for supporting the other side of the developer carrier are swingable independently of the developing casing. It is about installing as much as possible.

If the first support member and the second support member are not allowed to swing independently when supporting the developer carrier at two places, one side of the developer carrier is pressed by the pressing means and the image is formed. Although it is set at an accurate position with respect to the image forming body, it may not be set at an accurate position with respect to the image forming body even if another side of the developer carrier is pressed by the pressing means. Therefore, when the first support member and the second support member are configured to be swingable independently of each other, both ends of the developer carrier are appropriately pressed by the pressing means, respectively, so that the image forming body and the developer carrier are pressed. The positional relationship of the body can be set accurately.

Also, at this time, the positional relationship between the developer carrying member and the developer layer thickness regulating member can be maintained constant.

The invention according to claims 1 to 10 provides a developing sleeve and an image forming device by providing pressing means for independently pressing a supporting member for supporting both ends of a developer carrier and a developer layer thickness regulating member. The gap with the formation is set exactly. Therefore, it is possible to form an image with a constant density. In addition, by supplying power to the developing sleeve using the pressing means, it is not necessary to separately provide a power supply component, and the number of components and the number of assembly steps can be reduced.

Prior to the description of the embodiment of the present invention, the configuration and operation of a color printer as an example of an image forming apparatus equipped with a plurality of developing devices of the present invention will be described with reference to the cross-sectional configuration diagram of FIG.

This color printer superimposes each color toner image sequentially formed on an image forming body, transfers the color toner image on recording paper once by a transfer unit to form a color image, and then separates the color image from a surface of the image forming body by a separating unit. This is a color image forming apparatus of a peeling type.

In FIG. 1, reference numeral 10 denotes a photosensitive drum as an image forming body, which is formed by applying an OPC photosensitive body (organic photosensitive body) on a drum base, and is grounded and driven to rotate clockwise in the drawing. Reference numeral 11 denotes a scorotron charger, which uniformly applies a high potential VH to the peripheral surface of the photoreceptor drum 10 by corona discharge using a grid maintained at a grid potential VG and a corona discharge wire. Prior to the charging by the scorotron charger 11, in order to eliminate the history of the photoconductor up to the previous print, exposure is performed by a PCL (pre-charging static eliminator) 12 using a light emitting diode or the like, and the peripheral surface of the photoconductor is neutralized. deep.

(4) After the photosensitive drum 10 is uniformly charged, the image exposure means 13 performs image exposure based on the image signal. The image exposing means 13 is a main scanning performed by bending an optical path by a reflection mirror 134 through a polygon mirror 131, an fθ lens 132, and a cylindrical lens 133 which rotate by using a laser diode (not shown) as a light emitting light source. A latent image is formed by (sub-scan). In the present embodiment, a character portion is exposed to form a reversal latent image such that the character portion has a lower potential VL.

Around the periphery of the photosensitive drum 10, developing devices 14Y, 14M, each containing a two-component developer composed of a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier. A developing device 14 including 14C and 14K is provided. First, development of the first color yellow is performed by a developer carrier (developing sleeve) 141 which rotates while holding a developer with a built-in magnet. The developer consists of a carrier with ferrite as the core and an insulating resin coated around it, and a toner with polyester as the main material and a pigment according to the color, a charge control agent, silica, titanium oxide, etc. The developer is regulated to a layer thickness (developer) of 100 to 600 μm on the developing sleeve 141 by the layer forming means, and is conveyed to the developing area.

As 0.2~1.0mm gap is greater than the developer layer thickness between the developing sleeve 141 and the photosensitive drum 10 in the developing zone, DC bias of AC bias and V _DC of V _AC is applied so as to overlap the meantime You. V _DC and V _H, for charging the toner are the same polarity, the toner given the opportunity to leave from the carrier by V _AC is not adhere to a portion of the high V _H of potential than V _DC, potential than V _DC Adhered to the low V _L portion, and visualization (reverse development) is performed.

After the visualization of the first color has been completed, the image forming process for the magenta of the second color is started, and uniform charging is performed again by the scorotron charger 11, and a latent image based on the image data of the second color is formed by the image exposure means 13. You. At this time, the charge elimination by the PCL 12 performed in the image forming process of the first color is not performed because the toner attached to the image portion of the first color scatters due to a sharp drop in the surrounding potential.

A latent image similar to that of the first color is formed on a portion of the photoconductor having a potential of _VH again over the entire peripheral surface of the photoconductor drum 10 where the first color image is not formed, and development is performed. the potential difference in the portion to perform re-development to part there is an image of the first color, 1 V _M by color toner adhering to the charge possessed by the shading and toner itself 'latent image is formed, V _DC and V _M' Is performed in accordance with. In the overlapping portion of the first color image and the second color image, if the development of the first color is performed by creating a _VL latent image, the balance between the first color and the second color is lost. There may be an intermediate potential where _H > V _M > V _L.

The same image forming process as that of magenta of the second color is performed for cyan of the third color and black of the fourth color, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

The toner supply device that controls and replenishes each of the developing units 14Y, 14M, 14C, and 14K with new color toners includes a plurality of detachable toner cartridges 15 (Y, M, C, and K), and a toner storage unit 16 ( Y, M, C, K) and the toner conveying means 17 (Y, M, C, K).

On the other hand, one sheet of the transfer material (transfer paper or the like) P carried out from the paper feed cassette 18 via the half-moon roller 181 temporarily stops, and when the transfer timing is adjusted, the registration roller pair 182 of the paper feed unit rotates. The paper is fed to the transfer area by the operation.

(4) In the transfer area, the transfer means 19 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing, and the multi-color image is collectively transferred while sandwiching the fed transfer material P.

Next, the transfer material P is neutralized by the separating means 20, separated from the peripheral surface of the photosensitive drum 10 and conveyed to the fixing device 22, where the heat roller (upper roller) 221 and the pressure roller (lower roller) 222 are heated and heated. After the toner is fused by the pressure, the toner is discharged onto a discharge tray 24 outside the apparatus via a discharge roller 23. The transfer means 19 is retracted from the peripheral surface of the photoreceptor drum 10 after the transfer material P has passed, and prepares for the formation of the next toner image.

On the other hand, the photosensitive drum 10 from which the transfer material P has been separated is cleaned by removing the residual toner by pressing the blade 211 of the cleaning device 21 and receiving the charge by the PCL 12 and the charge by the scorotron charger 11 again to form the next image. Enter the process. The blade 211 moves immediately after the cleaning of the surface of the photoconductor and moves away from the peripheral surface of the photoconductor drum 10. The waste toner scraped into the cleaning device 21 by the blade 211 is discharged by the screw 212 and then stored in a waste toner collecting container (not shown).

FIG. 2 is a cross-sectional view illustrating a configuration of the developing device 14 including a plurality of developing devices. Around the periphery of the photosensitive drum 10, developing devices 14Y, 14M, 14C, each containing a developer including a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier, are provided. A developing device 14 of 14K is provided. The developing device housing 140 includes a developing device housing 140Y for the developing device 14Y, a developing device housing 140M for the developing device 14M, and a developing device housing 140C for the developing device 14C arranged in a three-tiered configuration. Are mounted, these four members are stacked, positioned and integrated to form three developer chambers isolated from each other. Since these developing units 14Y, 14M, 14C, and 14K have substantially the same configuration, these developing units will be hereinafter referred to as a developing device 14 as a representative.

FIG. 3 is a sectional view of the developing device 14. In the figure, reference numeral 140 denotes a developer housing for containing a two-component developer composed of toner and carrier, and 141 denotes a developer conveying means having a magnetic field generating means (magnet roll) 142 having a fixed magnet inside. A carrier (hereinafter, referred to as a developing sleeve), 143 is a developer supply roller (hereinafter, referred to as a supply paddle), and 144 is a developer layer thickness regulating member that regulates a developer layer thickness on the developing sleeve 141 to a predetermined amount. 145A and 145B are developer stirring screws (hereinafter referred to as stirring screws), and 171 is a toner supply port opened at the upper part of the developing device housing 140 and is provided from the toner cartridge 15. The toner supplied via the toner storing means 16 and the toner conveying means 17 is received.

FIG. 4 is a plan sectional view of the developing device 14. The vicinity of both shaft ends of the developing sleeve 141 is rotatably supported by ball bearings (ball ring) 147A and 147B provided on support members 146A and 146B. In the vicinity of both shaft ends of the developing sleeve 141, butting rollers 148A and 148B are rotatably supported via ball bearings. The outer peripheral surfaces of the abutting rollers 148A and 148B come into contact with both ends of the outer peripheral surface of the image forming body 10 to keep the gap between the image forming body 10 and the developing sleeve 141 constant. Both ends of the magnetic field generating means 142 having a plurality of magnetic poles are fixedly supported by support members 146A and 146B. The developing sleeve 141 is driven and rotated by a driving source (not shown) connected to a gear G1 fixed to one shaft end. G2 is a gear for transmitting drive to the rotating shaft of the stirring screw 145A, and G3 is a gear for transmitting drive to the rotating shaft of the stirring screw 145B.

FIG. 5 is a front sectional view of the developer carrier 141 and the layer thickness regulating member 144. The layer thickness regulating member 144 is formed by using a magnetic member 144A in a region substantially the same as the image forming region, and press-fitting a non-magnetic member 144B into projections at both ends of the magnetic member 144A. If the surface of the joint is polished after the press-fitting, the unevenness of the joint is eliminated. As the magnetic material, magnetic stainless steel SUS430 is preferable. Examples of the non-magnetic member include an aluminum alloy and a copper alloy, but non-magnetic stainless steel SUS304 is particularly preferable. As described above, the developer hardly adheres to the region using the non-magnetic material, and the lateral leakage of the developer can be prevented.

FIG. 6A is a partial cross-sectional view showing another embodiment of the layer thickness regulating member 144. The layer thickness regulating member shown in the figure is obtained by turning the shaft end of the magnetic member 144A to form a small-diameter portion, and press-fitting a ring-shaped nonmagnetic member 144C into the small-diameter portion. Can be

FIG. 6B is a partial cross-sectional view showing still another embodiment of the layer thickness regulating member 144. The layer thickness regulating member shown in the drawing is such that a disk-shaped shielding member 144D whose outer shape is larger than the outer shape of the magnetic member 144A is fitted into the protrusion at the shaft end of the magnetic member 144A, and then the non-magnetic member 144B is fitted to the protrusion. Are integrated by press-fitting. By interposing the shielding member 144D, the movement of the developer in the axial end direction outside the image forming area of the layer thickness regulating member 144 is prevented. As the shielding member 144D, a flexible film made of a nonmagnetic material, polyethylene terephthalate (PET), is preferable, but other materials can also be used. Further, a magnetic material can be used as the shielding member 144D.

FIG. 7 is a side view of the developing device of the present invention.

The support members 146A and 146B are rotatably supported by a pair of engaging portions (rotating pins) 149 implanted on both side walls of the developing device housing 140. A hole formed at one end of the pressing means 150, which is a leaf spring having elasticity, is fitted into one axial end of the magnetic field generating means 142, and is electrically connected to the developing sleeve 141. I have. The other end of the pressing means (leaf spring) 150 has a curved shape and is elastically deformable. The curved surface portion of the leaf spring 150 is pressed against the end surface of the conductive wiring member 151 fixedly disposed on the side surface of the developing device housing 140 with a predetermined pressing force. The leaf spring 150 is formed of an elastic material having conductivity, and is manufactured by pressing a phosphor bronze plate, a beryllium bronze plate, a stainless steel plate, or the like. Note that the pressing means 150 is not limited to the above-mentioned leaf spring, and other means can be applied as long as the material and the material have conductivity and elasticity. By the predetermined elastic pressing force of the pressing means 150, the abutting rollers 148A and 148B are pressed against the outer peripheral surface of the image forming body 10, and the developing sleeve 141 approaches the image forming body 10 while maintaining a predetermined gap. The support members 146A and 146B for supporting the developing sleeve 141 and the like are independently and swingably supported on both end surfaces of the developing device casing 140, and are pressed by individually provided pressing means 150, and are pressed against the abutting rollers 148A. , 148B, the gap between the developing sleeve 141 and the image forming body 10 is kept constant.

FIG. 8 is a side view showing a state in which the developing device 14 is separated from the outer peripheral surface of the image forming body 10. In this separated state, the supporting members 146A and 145B supporting the developing sleeve 141 rotate the engaging portion (rotating pin) 149 in the figure by the pressing force of the pressing means 150 and the weight of the developing sleeve 141, the magnetic field generating means 142 and the like. It rotates counterclockwise in the figure as a fulcrum.

Although the pressing means 150 may be provided at both ends of the developing sleeve 141, in the configuration shown in this embodiment, one side of the developing sleeve 140 is pressed by the second pressing means 150 made of an elastic member such as a leaf spring. The other side is pressed by the rotational driving force of the gear G1 (first pressing means) connected to the driving source. Since the pressing force of the first pressing unit 150 and the pressing force of the gear G1 serving as the second pressing unit act independently, the pressing force between the developing sleeve 141 and the image forming body 10 is increased in the same manner as described above. The gap is kept constant.

The developing device of the present invention is not limited to a color image forming device having a plurality of developing devices, but is also applicable to a monochrome image forming device with one developing device. However, in the case of a color image forming apparatus, the effects of downsizing and cost reduction of the apparatus are particularly remarkable.

FIG. 1 is a cross-sectional configuration diagram of a color printer as an example of an image forming apparatus equipped with a developing device of the present invention. FIG. 2 is a cross-sectional view of a developing device including a plurality of developing devices. FIG. 3 is a cross-sectional view of the developing device. FIG. 3 is a plan sectional view of the developing device. FIG. 3 is a front cross-sectional view of a developer carrying member and a layer thickness regulating member of the developing device. FIG. 9 is a partial cross-sectional view showing another embodiment of the layer thickness regulating member. FIG. 2 is a side view of the developing device of the present invention. FIG. 4 is a side view showing a state in which the developing device is separated from an outer peripheral surface of the image forming body.

Explanation of reference numerals

10 Photoconductor drum (image forming body)
14 Developing device 14Y, 14M, 14C, 14K Developing device 140 Developing device housing 141 Developer carrier (developing sleeve)
142 Magnetic field generating means (magnet roll)
144 Developer layer thickness regulating member (layer thickness regulating member)
144A Magnetic member 144B, 144C Non-magnetic member 144D Shielding member 146A, 146B Support member 148A, 148B Butt roller (gap holding member)
149 Engagement part (rotating pin)
150 pressing means (elastic member)
151 conductive wiring member

Claims (10)

At least a developing device having a developer carrier facing the image forming body and supplying a developer to the image forming body, and a developing device casing for housing the developer, rotatably supporting the developer carrying body. A developing apparatus comprising: a support member swingably mounted on the developing device casing; and pressing means for pressing the developer carrier against the image forming body. The support member is engaged with an engaging portion of the developing device casing or an engaging portion provided on the developing device casing, and is swingably provided around the engaging portion as a fulcrum. The developing device according to claim 1. The developing device according to claim 1, wherein the support member supports a developer layer regulating member provided substantially in parallel with a surface of the developer carrier that carries the developer. The developer carrier has a magnetic field generator inside the developer carrier, and the developer layer regulating member is provided opposite to the magnetic pole of the magnetic field generator, and the developer layer regulating member is made of a magnetic material. The developing device according to claim 3, wherein: The image forming body and the developer carrying member have a gap therebetween, and the gap is maintained by a gap holding member abutting on the image forming body. The developing device according to claim 1. The developing device according to claim 1, wherein the pressing unit includes an elastic member. The developer carrier and the image forming body have a gap between them, the developer carrier receives a power supply for forming an electric field in the gap, and the elastic member supplies the power supply. The developing device according to claim 6, wherein the developing device comprises a conductive member. The developing device according to claim 1, wherein the pressing unit is a pressing unit that obtains a pressing force by a driving source that rotationally drives the developer carrier. The support member includes a first support member that supports at least one location of the developer carrier, and a second support member that supports another location of the developer carrier. Means for pressing the first support member by a driving source for rotating the developer carrier so as to press the developer carrier against the image forming body; and The image forming apparatus according to claim 1, further comprising a second pressing unit configured to press the second support member with an elastic member so as to press a developer carrier against the image forming body. Item 6. The developing device according to item 1. The support member includes a first support member that supports at least one location of the developer carrier, and a second support member that supports another location of the developer carrier. The developing device according to any one of claims 1 to 9, wherein the one support member and the second support member are independently and swingably installed on the developing device casing.

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