JP2000147885A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent banding and failure in a thin layer of a developer on a developer carrier by restricting the quantity of the developer fed to a contact part between the developer carrier and a developer feeding member. SOLUTION: In this developing device, a separating part 40C is provided on the more upstream side from the contact part F of the developing roll 23C and a feeding roll 25C in the rotating direction of the feeding roll 25C. Furthermore, even when a developing device 22C is filled full with a toner, the toner is not fed excessively to the area E in the vicinity of the contact part. Developer is one component developer and a thin layer blade 26C which makes the developer into a thin layer treat-abutting on the developing roll 23C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device such as a copying machine, a facsimile, a printer, and the like. More particularly, the present invention relates to a developer carrier disposed at a position facing an image carrier, and to a developer carrier. The present invention relates to a developing device including a developer supply member that supplies a developer, and a developer storage unit that supplies a developer to a developer carrier and a developer supply member.

[0002]

2. Description of the Related Art Conventionally, in a developing device which has been put to practical use, a uniform toner layer is formed on the surface of a developing roller as a developer carrier, and the toner carried on the surface adheres to the surface of the latent image carrier. Various methods have been adopted to perform good image formation. For example, JP-A-5-31488
In the developing device disclosed in Japanese Patent Application Publication No.
A supply roller made of an elastic member having a cylindrical outer shape as a developer supply member that supplies toner while rotating on the development roller, and a thin layer blade that contacts the development roller and thins the toner on the surface of the development roller. Provided in the developing case.
The supply roller is disposed so as to rub a part of the peripheral surface thereof with the developing case, and the developing case is used as a contact member. Thus, in the developing device, aggregation and fixation of the toner on the surface of the supply roller and the like are prevented.

[0003]

However, as in the developing device disclosed in JP-A-5-31488,
In the conventional developing devices, there is no regulation of the toner at the contact portion between the developing roller and the supply roller. That is, there is no regulation on the amount of toner in the portion of the supply roller that becomes the developer supply position to the developing roller. In general, a supply roller made of an elastic body or a foamed body is easily deformed and changes the amount of toner sandwiched in a contact portion with the developing roller, so that the frictional resistance between the supply roller and the developing roller is changed to rotate the developing roller. Causes unevenness. When rotation unevenness occurs in the developing roller, banding occurs as a density difference in a formed image. In particular, when the developing case is full of toner, the toner is excessively supplied to the above-mentioned contact portion, and the powder pressure of the toner is applied. Failure may occur.

The present invention has been made in view of the above problems, and has as its object to regulate the amount of toner supplied to a contact portion between a developer carrying member and a developer supply member.
An object of the present invention is to provide a developing device capable of preventing banding and a defective toner thin layer on a developer carrying member.

[0005]

In order to achieve the above object, a developing device according to any one of claims 1 to 4 includes a developer carrier disposed at a position facing the image carrier, and a developer carrier disposed at a position facing the image carrier. In a developing device having a developer supply member that supplies a developer, and a developer carrier and a developer storage unit that replenishes the developer to the developer supply member, a contact portion between the developer carrier and the developer supply member Further, a partitioning portion for separating the developer accommodating portion and the contact portion is provided further upstream in the rotation direction of the developer supply member.

According to a second aspect of the present invention, in the developing device of the first aspect, the developer is a one-component developer, and the developer on the developer carrier is brought into contact with the developer carrier to form a thin layer. Wherein the developing agent regulating member is brought into contact with the trading.

In the developing device according to any one of the first to fourth aspects, the partition provided on the upstream side in the rotation direction of the developer supply member from the contact portion between the developer carrier and the developer supply member,
The developer accommodating section and the contact section are partitioned, and the developer is supplied from the developer accommodating section to the contact section via the partition section. Thereby, the amount of the developer supplied from the developer accommodating portion to the contact portion can be regulated. In particular, even when the developer is full in the developing device, it is possible to prevent the developer from being excessively supplied to the contact portion and applying excessive powder pressure of the developer.

According to a third aspect of the present invention, in the developing device of the first aspect, a contact member that comes into contact with the developer supply member and scrapes the developer also serves as a part of the partition portion. It is assumed that. In the developing device according to the third aspect, the provision of the contact member prevents the developer from aggregating and fixing on the surface of the developer supply member even after the developer is supplied from the developer supply member to the developer carrier. Can be prevented. Further, in the developing device according to the third aspect,
Since the contact portion also serves as a part of the partition, the device can be simplified and the cost can be reduced by reducing the number of parts as compared with the case where the contact portion and the partition are provided independently.

According to a fourth aspect of the present invention, in the developing device of the first aspect, an end of the partition portion elastically contacts the developer supply member.
In the developing device according to the fourth aspect, since the end of the partition portion is in elastic contact with the developer supply member, the adhesion between the partition portion and the developer supply member is further enhanced. Thereby, it is possible to sufficiently prevent the developer from entering the contact portion between the developer carrier and the developer supply member.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color printer as an image forming apparatus will be described below. First, the configuration and operation of the entire color printer according to the present embodiment will be described.

FIG. 1 is a schematic configuration diagram of a color printer according to the present embodiment. In FIG. 1, a flexible belt-shaped photoconductor (hereinafter, referred to as a photoconductor belt) 1 as a latent image carrier is shown.
Is mounted between the rotating rollers 2 and 3 and is conveyed in the direction of the arrow A (clockwise) in the figure by the rotation of the rotating roller 2. Around this photoreceptor belt 1, a charging charger 4 as a charging unit for uniformly charging the surface of the photoreceptor belt 1,
As will be described later, a laser writing system unit 5 that performs electrostatic image exposure based on an image writing signal, from three developing units each having a yellow (Y), magenta (M), and cyan (C) color developer. Color developing device 6 and a black developing device 7 provided with a black developer.

Further, an intermediate transfer belt 10 serving as an intermediate transfer member is provided.
Is provided between the rotation rollers 11 and 12 and is conveyed in the direction of arrow B (counterclockwise) in the figure by the rotation of the rotation roller 11. The photoreceptor belt 1 and the intermediate transfer belt 10
Contact at the position of the rotating roller 3 of the photoreceptor belt 1,
Here, the toner image on the photosensitive belt 1 is the intermediate transfer belt 1
0. A front end of a conductive bias brush 13 is in contact with a back surface of the intermediate transfer belt 10 at a contact portion between the photosensitive belt 1 and the intermediate transfer belt 10 under a predetermined condition. A transfer roller 14 for transferring the toner on the intermediate transfer belt 10 onto transfer paper is provided around the intermediate transfer belt 1.

Further, as described later, a waste toner collecting container 15 for removing toner remaining on the photosensitive belt 1 is provided near the rotating roller 2 with a cleaning blade 15a.
Is arranged in contact with the belt surface. In addition, a cleaning device 16 that removes toner remaining on the intermediate transfer belt 10 is provided near the rotating roller 11.

Image formation by the above-described color printer is performed as follows. First, when the laser writing system unit 5 is driven based on an image information signal sent from an external image reading device, a host computer, or the like, a laser beam L generated by a semiconductor laser (not shown) Rotationally scanned by a polygon mirror 5b rotating at a high speed by a polygon motor 5a, the fθ lens 5c
Then, the light path is bent by the reflection mirror 5d through the reflection mirror 5d and is emitted to the outside of the unit case 5e, and is scanned and exposed on the outer peripheral surface of the photosensitive belt 1 uniformly charged in advance by the charging charger 4. As a result, an electrostatic latent image is formed on the photosensitive belt 1. Here, the image pattern to be exposed is a single-color image pattern when a desired full-color image is separated into yellow, magenta, cyan, and black.

The electrostatic latent images of the three colors formed on the photoreceptor belt 1 are rotated by a rotating operation every 120 degrees around the circumference in synchronism with the developing timing of the corresponding color of the color developing device 6 to form a yellow image to be described later. , Magenta, and cyan developing units are sequentially moved to a developing position facing the photoreceptor belt 1 to be developed. As a result, a single-color image of each color is sequentially formed on the photosensitive belt 1. On the other hand, the electrostatic latent image corresponding to the black image on the photosensitive belt 1 is developed by the black developing device 7 moved to the developing position. Thereby, the photoreceptor belt 1
A black monochromatic image is sequentially formed thereon.

The single-color images developed on the photosensitive belt 1 are sequentially transferred onto an intermediate transfer belt 10 rotating in synchronization with the photosensitive belt 1 by a bias brush 13 applied to a predetermined transfer bias. Is done. Each time a single-color image is transferred onto the intermediate transfer belt 10, the toner remaining on the photosensitive belt 1 is scraped off by the cleaning blade 15 a and collected in the waste toner collecting container 15. You.

The yellow, magenta, cyan, and black images superimposed on the intermediate transfer belt 10 are
The transfer roller 14 collectively transfers the transfer paper 17a from the paper feed table (paper feed cassette) 17 onto the transfer paper 17a transported to the transfer unit via the paper feed roller 18, the transport roller pairs 19a and 19b, and the registration roller pairs 20a and 20b. (Secondary transfer). After the completion of the secondary transfer, the transfer paper 17a is fixed by the fixing device 80 to complete the full-color image, and the discharge rollers 81a and 81
The sheet is discharged to the sheet discharge stack section 82 via 1b. In addition, 2
The toner remaining on the intermediate transfer belt 10 after the next transfer is removed by the cleaning blade 16 of the cleaning device 16.
a, and is conveyed by the auger 16b toward the front of the drawing, and conveyed to the waste toner collecting container 15 by a conveying unit (not shown). The cleaning blade 16a is held at a position separated from the surface of the intermediate transfer belt 10 during the image transfer operation, and is configured to be in contact with the surface of the intermediate transfer belt 10 after image transfer.

This color printer comprises a front frame 8 as a front housing capable of releasing a transfer paper transport path and a main body frame 9 as an immovable housing. In a central portion of the main body frame 9, as a process cartridge 31, components including a photoreceptor belt 1, a charging charger 4, an intermediate transfer belt 10, a cleaning device 16, and a registration roller 20 b are integrally formed. The case exterior portion of the process cartridge 31 on the side of the registration roller 20b also has a function as a paper conveyance guide. In this color printer, the process cartridge 31, the color developing device 6, and the black developing device 7 are exchangeably arranged. Further, the waste toner collecting container 15 is exchangeably built into the process cartridge 31. By replacing the process cartridge 31 when a predetermined amount or more of waste toner is stored in the waste toner collection container 15, the life of the process cartridge 31 can be extended.

Here, the developing device which characterizes the present embodiment will be described in detail. First, the color developing device 6 will be described with reference to FIGS.

As shown in FIGS. 2 and 3, the color developing device 6 is a so-called rotary type (also referred to as revolver type or rotary type) developing device using a non-magnetic one-component developer. The developing units 22Y, 22M, and 22C that respectively store yellow, magenta, and cyan toners are provided in a casing 21 that rotates. Each of the developing devices 22Y, 22M, and 22C is provided with a cylindrical developing roller 23Y, 23M, and 23C as a developer carrier. Each of these developing rollers 23Y, 23M, 23
C is rotated in the direction of arrow D by a drive mechanism (not shown) in synchronization with the color information, and is arranged such that a portion thereof is exposed to the outside from an opening 21 a provided in the casing 21. As described above, the electrostatic latent images formed on the photosensitive belt 1 are sequentially developed. FIG. 2 shows a state in which the developing device 22C containing the cyan toner is at the developing position.

Hereinafter, the developing units 22Y, 22M, 22C
Have the same form and the same operation, and therefore, a description will be given by taking the developing device 22C containing cyan toner as an example. As shown in FIG. 4, when the developing device 22C is at the developing position, the developing roller 23C is disposed at a position facing the photoreceptor belt 1 so as to partially expose the opening 21a. The developing roller 23C is disposed so as to rotate in the same direction as the photoconductor moving direction A with a predetermined peripheral speed ratio with respect to the photoconductor belt 1.

Below the developing roller 23C,
A supply roller 25C as a developer supply member made of an elastic material such as foamed polyurethane rubs against the development roller 23C,
Further, it is arranged so as to rotate in the same direction as the developing roller 23C at the contact portion at a predetermined peripheral speed ratio with respect to the developing roller 23C. On the downstream side in the moving direction of the developing roller 23C from the contact portion F between the supply roller 25C and the developing roller 23C, in the vicinity of the opening 21a, a thin plate having a spring property such as stainless steel or urethane rubber is used as a developer regulating member. A thin-layer blade 26C made of an elastic material such as is provided so that the vicinity of one end thereof is in contact with the developing roller 23C.

Further, as shown in FIG. 5, on the front side of the color developing device 6, cyan, magenta, and yellow toners are accommodated, and toner is supplied to each of the developing units 22C, 22M, and 22Y to supply the toner. Parts 29C, 29M, 29Y
Are provided respectively. These toner storage units 29
C, 29M, and 29Y have toner cartridges 30C, 30M, 30 for supplying toner to the outer peripheral portions thereof.
Y are provided respectively. Toner cartridge 30
Is detachably attached to the toner storage unit 29, is mounted and replaced when the color developing device 6 is newly mounted and at the time of toner end, and always supplies necessary toner into the toner storage unit 29. The developing device 22, the toner container 29, and the toner cartridge 30 all rotate integrally about a rotation axis.

As shown in FIGS. 4 and 6, at a position facing the contact portion F between the developing roller 23C and the supply roller 25C, the toner is moved from the toner container 29C on the near side of the developing device toward the back. And a second toner conveying member 28C for conveying the toner from the rear side of the developing device to the front side below the supply roller 25C. I have. First toner transport member 27C and second toner transport member 28C
Are the developing roller 23C and the supply roller 2 from the toner storage portion 29C to the side plate (the left side surface in the drawing) on the opposite side in the longitudinal direction.
5C, is arranged in parallel with the developing roller 23C and the supply roller 25C, and is rotated at a predetermined peripheral speed ratio. In addition, as shown in FIG.
Is arranged so that a part thereof is in contact with the supply roller 25C, and the developing roller 23C, the supply roller 25C, and the casing 21C form a toner transport space 24C surrounding the first toner transport member 27C.

In the developing device 22C configured as described above, the first toner conveying member 27C is
The toner is transported from 9C into the toner transport space 24C, and is supplied onto the supply roller 25C. The toner supplied on the supply roller 25C is supplied while being charged on the surface of the developing roller 23C by the supply roller 25C,
It is carried on the surface of the developing roller 23C. Developing roller 23C
The toner carried on the surface is made into a uniform and thin layer of toner by the thin layer blade 26C, and the electrostatic latent image formed on the surface of the photoreceptor belt 1 is developed by contact or non-contact development. On the other hand, the toner not used in the developing step is transported by the first toner transport member 27C to the toner circulating section 31C on the side opposite to the toner storage section 29C in the longitudinal direction. The toner transported to the toner circulating unit 31C falls to the lower part of the developing unit 22C by gravity, and is transported to the toner storage unit 29C by the second toner transporting member 28C. Thus, the first toner conveying member 27
By appropriately setting the toner transport amount of C and the second toner transport member 28C, toner can be supplied onto the supply roller 25C without detecting the toner amount in the developing device 22C or performing complicated supply amount control. It is possible to provide a small-sized developing device having a large degree of freedom in layout and a small sectional occupation ratio with respect to the photoconductor.

Note that the color developing device 6 waits and stops at the developing device home position as shown in FIG. 3 except during the image forming operation, ie, before and after the image forming operation. In the present embodiment, the developing roller 23C of the cyan developing device 22C and the developing roller 23C of the yellow developing device 22Y are used.
The home position is a position approximately halfway between Y and the position where the developing rollers 23C and 23Y do not contact the surface of the photosensitive belt 1. This is because the cyan developing device 22C, which is used first when performing the color developing operation in the present embodiment, moves faster in the developing position due to the rotation of the color developing device 6 in the direction of arrow D in FIG. It is a position that can be accurately reached, and prevents the photosensitive belt 1 and the developing roller 23 from being deteriorated or damaged due to unnecessary contact between the photosensitive belt 1 and the developing roller 23 during non-operation. This position prevents the toner from adhering or sticking.

Here, as shown in FIG. 4, in the developing device 22C according to the present embodiment, the elastic member is located upstream of the contact portion F between the developing roller 23C and the supply roller 25C in the rotation direction of the supply roller 25C. Film-shaped partition part 4
OC-shaped contact member 41 having a cylindrical outer shape made of metal or resin
C is provided. The partitioning section 40C partitions the toner transporting space 24C including the toner storing section 29C from the contact section F, and a partitioning member for preventing the toner transported from the toner storing section 29C from being directly supplied to the contacting section F. Has become. One end of the partition part 40C is fixed to the wall surface of the casing 21C, and the other end is abutting member 41.
It is provided so as to elastically contact the supply roller 25C via C. On the other hand, the contact member 41C has both ends fixed to the side plate of the casing 21C and the supply roller 25C.
And are arranged in parallel. In the present embodiment, by configuring the supply roller 25C from an elastic body, the partition 40C and the supply roller 25C are configured to elastically contact even if the contact member 41C is made of metal or resin. ing.

As described above, in the developing unit 22C, by providing the partitioning portion 40C, the partitioning portion 40C and the contact member 41C allow the developing unit 22C to be located in the region E near the contact portion F between the developing roller 23C and the supply roller 25C. , Transport space 2
The toner in 4C can be supplied in an appropriate amount.
Therefore, even when the toner is full in the casing 21C, the toner is not excessively supplied into the area E. For this reason, the toner powder pressure is not excessively applied to the contact portion F, and banding due to load fluctuation of the supply roller 25C and a thin toner layer defect on the developing roller 23C that causes moiré and spots on an image occur. Can be prevented.

By providing the contact member 41C, it is possible to prevent the toner from aggregating and sticking to the surface of the supply roller 25C even after the toner is supplied from the supply roller 25C to the developing roller 23C. Thereby, the uniformly charged developer can be supplied onto the supply roller 25C, and a uniform image density can be obtained. Further, by employing a configuration in which the contact member 41C also serves as a part of the partition portion 40C, it is possible to reduce the number of parts and cost as compared with a case where the partition portion and the contact portion are provided independently. Further, by forming the partition 40C from an elastic body, the adhesion between the contact member 41C and the supply roller 25C is enhanced, and even when the parallelism between the contact member 41C and the supply roller 25C is small, It is possible to sufficiently prevent toner from entering the area E.

Further, in the present embodiment, the thin layer blade 2
By providing 6C, the toner on the developing roller 23C can be made uniform and a thin layer with a predetermined thickness, so that banding and a thin layer defect on the developing roller 23C can be reliably prevented.

In this embodiment, the cyan developing device 22
The example in which the partitioning portion 40C and the contact member 41C are provided for C has been described, but other color developing devices 22M and 22Y are provided.
It goes without saying that the same applies to

Next, the black developing device 7 will be described. As shown in FIG. 7, the black developing device 7 is a developing device of a type in which a black toner is contained in a developing container 71 as a developer accommodating portion. This is a developing unit integrally formed as a cartridge. The black developing device 7 is configured such that a developing roller 23K as a developer carrier is exposed in an opening 71a in a developing container 71 at a position facing the photoreceptor belt 1 as an image carrier. It is arranged so as to rotate in the same direction as the moving direction of the body belt 1. In the developing container 71, a supply roller 25K made of an elastic material such as foamed polyurethane is formed in parallel with the developing roller 23K and in contact with the developing roller 23K at a predetermined contact pressure to form a nip. The developing roller 23K is arranged so as to rotate in a direction opposite to the moving direction of the developing roller 23K at a contact portion with the developing roller 23K. Further, downstream of the contact portion F between the developing roller 23K and the supply roller 25K in the moving direction of the developing roller 23K,
In the vicinity of the opening 71a, a thin blade 26K as a developer regulating member made of a thin plate having a spring property such as stainless steel or an elastic body such as urethane rubber contacts one end of the blade near the developing roller 23K. Is provided.

In the developing container 71, the developing container 71
A first agitator 73 that stirs the toner inside and conveys the toner to the supply roller 25K and the developing roller 23K side;
Again, the toner in the developing container 71 is agitated, and the supply roller 2
A second agitator 74 for transporting the toner to the 5K and the developing roller 23K side is disposed in parallel with the developing roller 23K and the supply roller 25K. First agitator 7
Third, a film-like elastic sheet or the like is attached to the second agitator 74 so that the leading end thereof slides on the bottom of the developing container 71. As a result, the toner in the developing container 71 can be efficiently transported, and the remaining amount of the toner in the developing container 71 can be reduced. It is desirable that the rotation speed of the agitators 73 and 74 be as low as possible so as not to apply extra stress to the toner.

As shown in FIG. 3, the developing roller 23K is located at a position where the developing roller 23K is separated from the surface of the photoreceptor belt 1 by a cam 75 and a spring (not shown) except during the image forming operation. Will be retained. Developing roller 2
In a state where 3K is not in contact with the photoreceptor belt 1, the driving of the developing roller 23K is turned off so that the developing roller 23K is controlled so as not to rotate. The roller 23K and other components of the developing device 7 are prevented from being deteriorated early. On the other hand, at the time of image formation, that is, when the black developing device 7 develops a black latent image formed on the photoreceptor belt 1, as shown in FIG. Is moved in the horizontal direction along a guide member (not shown) to bring the developing roller 23K into contact with the surface of the photoreceptor belt 1 with a predetermined nip.

Here, in the black developing device 7 according to the present embodiment, as shown in FIG. 7, a foaming member is disposed upstream of the contact portion F between the developing roller 23K and the supply roller 25K in the rotation direction of the supply roller 25K. And a cylindrical outer contact member 43 made of metal or resin. The partition part 42 partitions the inside of the developing container 71 as a toner storage part from the contact part F, and serves as a partition member for preventing the toner in the developing container 71 from being directly supplied to the contact part F. The partition 42 is provided such that one end thereof is fixed to the wall surface of the developing container 71 and the other end is in elastic contact with the supply roller 25K via the contact member 43. The contact member 43 has both ends fixed to a side plate of the developing container 71 and is arranged in parallel with the supply roller 25K. As described in the color developing device 6, in the present embodiment, by forming the supply roller 25K from an elastic material, the partition member 42 and the supply roller 25K are configured such that the contact member 43 is made of metal or resin. Are also configured to resiliently contact.

As described above, in the black developing device 7, by providing the partition 42, the developing roller 23K and the supply roller 25K are interposed via the partition 42 and the contact member 43.
A suitable amount of toner in the developing container 71 can be supplied into a region E near the contact portion F with the toner. Therefore,
In particular, even when the developing device 71 is full of toner, the toner is not excessively supplied into the area E. Therefore, the toner powder pressure is not excessively applied to the contact portion F, and banding due to load fluctuation of the supply roller 25K, and a thin toner layer defect on the developing roller 23K that causes moiré and spots on an image occur. Can be prevented.

As described in the color developing device 6, the provision of the contact member 43 allows the supply roller 25 to be provided.
Even after the toner is supplied from K to the developing roller 23K, it is possible to prevent the toner from aggregating and sticking to the surface of the supply roller 25K. Thereby, the uniformly charged developer can be supplied onto the supply roller 25K, and a uniform image density can be obtained. Further, the configuration in which the contact member 43 also serves as a part of the partition part 42 leads to a reduction in the number of parts and a cost reduction as compared with a case where the partition part and the contact part are provided independently. By forming the partition 42 from an elastic body, the adhesion between the contact member 43 and the supply roller 25K is enhanced, and even when the parallelism between the contact member 43 and the supply roller 25K is small, It is possible to sufficiently prevent toner from entering the area E.

Further, in the present embodiment, the thin layer blade 2
By providing the 6K, the toner on the developing roller 23K can be made uniform and a thin layer having a predetermined thickness, so that banding and a thin layer defect on the developing roller 23C can be reliably prevented.

In this embodiment, the contact member also serves as a part of the partition. However, the partition may be provided alone. For example, as shown in FIG. 44 and a cylindrical contact member 45 made of metal
May be independently provided.

[0040]

According to the present invention, the contact portion and the developer accommodating portion are partitioned by the partition provided near the contact portion between the developer carrier and the developer supply member. The amount of developer supplied to the contact portion can be regulated. Therefore, it is possible to prevent the developer powder pressure from being excessively applied to the contact portion. In particular, even when the developer is full in the developing device, the developer powder pressure is excessively applied to the contact portion. Banding due to
There is an excellent effect that the toner thin layer defect on the developing roller can be prevented.

In particular, according to the third aspect of the present invention, the contact member provided so as to contact the developer supply member prevents the developer from aggregating and sticking to the developer supply member. Since the uniformly charged developer is supplied to the supply member,
A uniform image density can be obtained. In addition, since the contact member also serves as a part of the partition portion, the apparatus can be simplified and the cost can be reduced by reducing the number of components.

In particular, according to the fourth aspect of the present invention, the adhesion between the partition portion and the developer supply member is enhanced, and the toner sufficiently enters the contact portion between the developer carrier and the developer supply member. Therefore, banding due to the powder pressure of the developer and a defect of the developer thin layer on the developer carrier can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a color printer according to an embodiment.

FIG. 2 is a cross-sectional view illustrating an internal configuration of a color developing device and a black developing device in the color printer.

FIG. 3 is a cross-sectional view illustrating an internal configuration of the color printer when the color developing device and the black developing device are not operated.

FIG. 4 is an enlarged sectional view of a main part showing a state when a cyan developing device of the color developing device is at a developing position.

FIG. 5 is a perspective view showing the internal configuration of the color developing device.

FIG. 6 is a longitudinal sectional view showing the internal configuration of the color developing device.

FIG. 7 is an enlarged sectional view of a main part showing an internal configuration of the black developing device.

FIG. 8 is an enlarged sectional view of a main part showing an internal configuration of another black developing device.

[Explanation of symbols]

 Reference Signs List 1 photoconductor belt 4 charging charger 5 laser writing system unit 6 color developing device 7 black developing device 10 intermediate transfer belt 14 transfer roller 15 waste toner collecting container 16 cleaning device 21 casing 22 color developing device 23 developing roller 24 toner transport space 25 supply Roller 26 Thin layer blade 27 First toner transport member 28 Second toner transport member 29 Toner storage unit 30 Toner cartridge 40, 42, 44 Partition unit 41, 43, 45 Contact unit

Claims (4)

[Claims] A developer supply member provided at a position opposed to the image carrier; a developer supply member for supplying a developer to the developer support; and a developer supply member for developing the developer support and the developer supply member. In a developing device having a developer accommodating section for replenishing the developer, the developer accommodating section is separated from the contact section between the developer carrying member and the developer supplying member on the upstream side in the rotation direction of the developer supplying member. A developing device provided with a partition. 2. A developer regulating member according to claim 1, wherein said developer is a one-component developer, and is in contact with said developer carrier to reduce the thickness of said developer on said developer carrier. A developing device in contact with the developing device. 3. The developing device according to claim 1, wherein a contact member that contacts the developer supply member and scrapes the developer also serves as a part of the partition. 4. The developing device according to claim 1, wherein an end of said partition portion elastically contacts said developer supply member.