JP2000075647A - Developing device, developing cartridge, and electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely prevent the occurrence of uncharged developer at both longitudinal ends of a developer carrier and to perform the steady, satisfactory formation of a developer thin layer on the developer carrier. SOLUTION: Developer charge application members 40 are arranged at both the longitudinal ends of the developer carrier 20YS, thereby electrically charging the non-magnetic one-component developer layer on the developer carrier 20YS. Also, a bias having the same polarity as the non-magnetic one-component developer is applied to the developer charge application member 40 via a flexible bias feed means 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic image forming apparatus, a developing cartridge detachable from a main body of the electrophotographic image forming apparatus, and an electrophotographic image forming apparatus detachable from the developing cartridge. .

Here, an electrophotographic image forming apparatus forms an image on a recording medium by using an electrophotographic image forming process, and includes, for example, an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer, etc.). Etc.), an electrophotographic facsimile machine, and an electrophotographic word processor.

[0003]

2. Description of the Related Art An electrophotographic image forming apparatus such as a color printer has a structure in which a charging roller to which a voltage as a primary charger is applied is pressed against an electrophotographic photosensitive member (photosensitive drum). The charging roller uniformly charges the surface of the electrophotographic photosensitive member before performing the electrostatic latent image.

Exposure to the electrophotographic photosensitive member is performed by a scanner having a laser diode. The laser diode emits light corresponding to the image signal and irradiates the polygon mirror. The reflected laser light scans the electrophotographic photosensitive member in the axial direction by a polygon mirror rotating at high speed. Then, the light is condensed on the surface of the electrophotographic photosensitive member via the coupling lens and the reflection mirror.

[0005] The surface of the electrophotographic photosensitive member is exposed by condensing a laser beam corresponding to an image signal to form an electrostatic latent image of each color.

In such an electrophotographic image forming apparatus, a developing device for developing an electrostatic latent image of each color formed on the electrophotographic photosensitive member is disposed at a position facing the electrophotographic photosensitive member. Thus, the developing sleeve as a developer carrying member is positioned so as to be opposed to the surface of the electrophotographic photosensitive member at a small interval.

At the time of image formation, a high voltage power supply of the main body of the electrophotographic image forming apparatus is connected to a developing sleeve of the developing apparatus, and a bias is applied. At the same time, it is coupled to driving means from a driving source of the main body of the electrophotographic image forming apparatus.

As one of such developing devices, a developing device 100 as shown in FIG. 9 has been proposed and put into practical use.
In this conventional developing device 100, a developing sleeve 104 is provided in a developing container 104 containing a non-magnetic toner 103 as a one-component developer at a position upstream of a developing blade 102 as a developer layer forming member in a rotation direction of a developing sleeve 102. 10
2. A toner 103 is supplied onto the developing sleeve 102 by providing an application roller 105 as a developer application body using a polyurethane foam or a sponge or a fur brush using a fur brush and rotating in the arrow F direction. I have.

The toner 103 supplied onto the developing sleeve 102 is sent to the contact portion between the developing blade 101 and the developing sleeve 102 with the rotation of the developing sleeve 102 to be thinned, and the photosensitive member as an image carrier is formed. The electrostatic latent image on the drum 15 is developed. Then, the toner 103 remaining without being consumed in the development on the developing sleeve 102 is peeled off by the application roller 105, and new toner 103 is supplied to the development sleeve 102 by the application roller 105 as described above, and the above-described operation is repeated. . At this time,
When a metal material is used for the developing sleeve 102,
The developing blade 101 made of a thin metal plate is not preferable in terms of abrasion of the developing sleeve 102, and it is necessary to use a rubber material such as urethane or silicon in order to obtain a good toner thin layer.

With this configuration, a thin layer of non-magnetic toner on the developing sleeve 102 can be formed satisfactorily.

However, in a developing device using a non-magnetic toner, since a non-magnetic toner is used, compared with a magnetic developing device which uses a magnetic toner and can easily hold the toner on the surface of a developing sleeve by the action of a magnetic field. Since magnetic attraction cannot be used, it is difficult to prevent the toner 103 from leaking out of the developing device 100.
In other words, except for the toner that has escaped from the pressure contact portion of the developing blade 101 to the developing sleeve 102 and is sufficiently frictionally charged, the developing sleeve 102 has no force to hold the toner. Leakage, that is, so-called toner leakage, easily causes a problem that the inside of the image forming apparatus is contaminated with toner.

For this reason, in a developing device using a non-magnetic toner, a flexible seal member 106 which is lightly pressed against the developing sleeve 102 is provided at the toner collecting portion below the developing container 104, and the undeveloped portion is formed. The passage of the toner is allowed, the toner 103 in the developing container 104 is prevented from leaking from a lower portion of the developing container 104, and an end seal member 107 is separately provided near the end of the developing sleeve 102.

FIG. 10 is a view of the developing device 100 shown in FIG. 9 viewed from the direction of the photosensitive drum 15. For convenience of explanation, the developing sleeve 102 is not shown, and the developing blade 101 is in contact with the developing sleeve 102. The portion N (see FIG. 9) is indicated by oblique lines. As shown in FIG. 10, both ends of the developing sleeve 102 and the opening 10 of the developing container 104 are formed.
An end seal member 107 made of a fiber material such as wool felt or Teflon pile or a foam material such as polyurethane foam or sponge rubber is provided in the gap 4a, and the gap between the longitudinal ends of the developing container 104 and the developing sleeve 102 is provided. 9 and by sandwiching both ends of the developing blade 101 between the developing sleeve 102 and the end sealing member 107 (that is, by the end sealing member 107, as shown in FIG. 9). At the contact portion of the developing sleeve 102 with the end seal member 107.
The toner is prevented from leaking from both ends of the developing blade 101 by pressing down from the back side of the developing blade 101).

However, in this conventional configuration, in order to secure the sealing performance, the end sealing member 10 is pressed at a pressure equal to or higher than a predetermined value.
7 need to be pressed against the developing blade 101, and the developing sleeve 102 extends from the contact nip portion N between the developing sleeve 102 and the developing sleeve 102 at both ends sandwiched between the developing sleeve 102 and the end seal member 107. The developing blade 101 is deformed along the surface. As a result, the longitudinal sides of both ends of the developing blade 101 tend to rise, and the developing sleeve 10
The developer layer formed on the developing sleeve 2 becomes excessively large as compared with other portions, and thus the toner 103 becomes insufficiently charged. The toner 103 is transferred from the both ends of the sleeve 102 to the photosensitive drum 15 as fog,
This causes a problem that the toner 103 scatters or leaks.

Therefore, as shown in FIG. 11, it has been proposed to provide oblique cut portions 108a at both ends of the developing blade 108. This oblique cut portion 108a is formed as shown in FIG.
As shown in FIG.
From the most downstream point N1 in the developing sleeve rotation direction of the contact nip portion (the area shown by oblique lines) N with the developing blade 108
Of the developing blade 108 is continuously reduced toward the outer end in the vicinity of both ends in the longitudinal direction of the developing blade 108, and at least the leading end 108b at the outer end of the developing blade 108 abuts. It is formed so as to be inside the nip portion N. For this reason, the inside of the longitudinal direction of both ends of the developing blade 108 tends to be lifted, and even if the developer layer formed on the developing sleeve 102 in this portion becomes excessively large compared to other portions, the portion in that portion is Since the contact nip area with the developing sleeve 102 is small and the edge is slightly contacted, the thin layer of non-magnetic toner can be favorably developed on the developing sleeve 102.

[0016]

However, when the developing operation using the above-described conventional developing device is repeated many times,
Since the contact nip area is small at both ends of the developing blade 108, the pressure per area is larger than the contact nip pressure at the center, and the toner 103 is easily caught in the contact nip N near the end of the developing blade 108. Become. Both ends of the contact nip N are caught by the toner, so that the developing blade 10
8, the toner layer is gradually thickened in a streak shape, and the electric adhesion (mirror) to the developing sleeve 102 is obtained.
And the toner 103 is transferred to the photosensitive drum 15 as a fog, or the toner spills out of the surface of the developing sleeve 102 to the outside, causing a problem that a so-called toner leak occurs, which significantly contaminates the inside of the image forming apparatus. Was.

Further, toner 103 sent along with the rotation of the developing sleeve 102 is deposited on the oblique cut portions 108a at both ends of the developing blade 108, and the toner 103 repeats the developing operation many times. It travels along the surface on the tip side (the surface of the oblique cut portion 108a) in the end direction. Then, the toner 103 transmitted on the surface on the front end side is supplied to the developing sleeve 1 through a small gap between the end seal member 107, the developing sleeve 102, and both ends of the developing blade 108.
Enter the 02 side. As a result, the surface of the end seal member 107 that contacts the developing sleeve 102 gradually becomes the toner 10.
3 and the developing sleeve 102 is scraped by the rubbing between the end seal member 107 and the developing sleeve 102.

The scraping of the developing sleeve 102 is performed by toner 103
Reduces the charge application. As a result, the electrical adhesion (mirror power) of the toner 103 to the developing sleeve 102 is reduced, and the toner 103 is transferred to the photosensitive drum 15 as fog, or the toner 103 spills out of the surface of the developing sleeve 102 to the outside. As a result, the inside of the image forming apparatus is significantly contaminated.

The toner 103 used in the developing device
Is excellent in transferability when transferring from the photosensitive drum 15 to a transfer material as a recording medium by a transfer unit (not shown), and removes untransferred residual toner remaining on the photosensitive drum 15 without being transferred onto a blade, a fur brush, or the like. Has high lubricity during cleaning by the cleaning means (1) and thus has the advantage that the friction of the photosensitive drum 15 is small. However, since the toner is spherical, the surface is smooth and the fluidity is particularly high. , Toner 1 toward developing sleeve 102
03 is remarkably seen.

The present invention is a further development of the above-mentioned prior art, and its main purpose is to reliably prevent the generation of uncharged developer at both ends in the longitudinal direction of the developer carrying member, An object of the present invention is to provide a developing device capable of stably and favorably forming a thin developer layer on a body.

Another main purpose is to prevent the generation of uncharged developer at both ends in the longitudinal direction of the developer carrier, which can be detachably attached to the main body of the electrophotographic image forming apparatus. An object of the present invention is to provide a developing cartridge capable of stably and favorably forming the above-mentioned thin layer of developer.

Another main purpose is to reliably prevent the generation of uncharged developer at both ends in the longitudinal direction of the developer carrying member and to stably form a thin layer of the developer on the developer carrying member. It is an object of the present invention to provide an electrophotographic image forming apparatus in which a developing cartridge which can be satisfactorily performed can be detachably mounted.

[0023]

To achieve the above object, a typical constitution of the present invention is as follows: (1): A non-magnetic one-component developer is formed on an electrophotographic photosensitive member by rotating while supporting the developer. A developer carrier for developing the latent image thus formed with the non-magnetic one-component developer; and a non-magnetic one-component developer for applying a thin layer of the non-magnetic one-component developer on the developer carrier. A developer layer forming member contacting via a magnetic one-component developer, and the developer at a downstream side in a rotational direction of the developer carrier with respect to a contact portion of the developer layer forming member with the developer carrier. A developer charging member that abuts both ends in the longitudinal direction of the carrier, a supporting member that rotatably supports the developer charging member, and the developer holding member that holds the developer charging member via the supporting member. A swing member for swingably holding the body; A swing support member for swingably supporting a member, wherein the developer charge applying member that swings together with the swing member against the developer carrier is contacted with the developer carrier. A bias having a voltage equal to or higher than the discharge starting voltage and having the same polarity as that of the non-magnetic one-component developer is applied to the non-magnetic one-component developer layer having a thin layer applied thereon through a flexible bias power supply unit. A developing device characterized in that: (1-2): a developing container containing a non-magnetic one-component developer, and extending along the longitudinal direction of an opening of the developing container, and rotating while carrying the non-magnetic one-component developer. A developer carrier for developing the latent image formed on the electrophotographic photoreceptor by the non-magnetic one-component developer, and a thin-layer coating of the non-magnetic one-component developer on the developer carrier. A developer layer forming member that abuts on the developer carrier via the non-magnetic one-component developer, and a developer carrier of the developer carrier that abuts on the developer carrier of the developer layer forming member. A developer application member for supplying and applying the non-magnetic one-component developer in contact with the developer carrier on the upstream side in the rotation direction, and a contact portion between the developer carrier of the developer layer forming member and the developer carrier; With respect to the longitudinal direction of the developer carrier on the downstream side in the rotational direction of the developer carrier. A developer charge applying member that contacts an end portion, a support member that rotatably supports the developer charge application member, and swings the developer charge application member with respect to the developer carrier via the support member. And a swing member that swingably holds the swing member and a swing support member that swingably supports the swing member. The agent charge imparting member may be biased at a voltage equal to or higher than the discharge start voltage and with the same polarity as the non-magnetic one-component developer with respect to the non-magnetic one-component developer layer thinly coated on the developer carrier. The developing device is applied through a flexible bias power supply unit. (2): In a developing cartridge detachably mountable to the main body of the electrophotographic image forming apparatus, the latent image formed on the electrophotographic photosensitive member is rotated by the non-magnetic one-component developer by carrying the non-magnetic one-component developer. A developer carrier that develops with a developer, and a developing device that contacts the developer carrier via the nonmagnetic one-component developer so as to apply a thin layer of the nonmagnetic one-component developer on the developer carrier. A developer contacting a longitudinal end portion of the developer carrier at a downstream side in a rotational direction of the developer carrier with respect to a contact portion between the developer layer-forming member and the developer carrier of the developer layer-forming member. An agent charge providing member, a support member rotatably supporting the developer charge providing member,
A swing member that swingably holds the developer charge applying member with respect to the developer carrier via the support member; and a swing support member that swingably supports the swing member. The developer charge applying member that swings together with the swinging member against the developer carrier and contacts the non-magnetic one-component developer layer thinly coated on the developer carrier. On the other hand, a developing cartridge characterized in that a bias having a voltage equal to or higher than a discharge starting voltage and having the same polarity as that of the non-magnetic one-component developer is applied via a flexible bias power supply unit. (2-2): in a developing cartridge detachable from the main body of the electrophotographic image forming apparatus, a developing container for storing a non-magnetic one-component developer, and extending along a longitudinal direction of an opening of the developing container; A developer carrier for developing the latent image formed on the electrophotographic photosensitive member by the nonmagnetic one-component developer by carrying and rotating the non-magnetic one-component developer; and A developer layer forming member that abuts on the developer carrier via the nonmagnetic one-component developer so as to apply the nonmagnetic one-component developer in a thin layer; and the developer carrier of the developer layer-forming member. A developer application body for supplying and applying the non-magnetic one-component developer by abutting the developer carrier on the upstream side in the rotation direction of the developer carrier with respect to a contact portion with the developer; A contact portion of the layer forming member with the developer carrier is provided. A developer charge applying member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotation direction of the developer carrier, a support member that rotatably supports the developer charge application member, and the developer A swing member that swingably holds the charge applying member with respect to the developer carrier via the support member, and a swing support member that swingably supports the swing member, The developer charge applying member that swings together with the swinging member against the developer carrying member starts discharging to the non-magnetic one-component developer layer thinly coated on the developer carrying member. A developing cartridge characterized in that a bias having a voltage equal to or higher than the voltage and having the same polarity as that of the non-magnetic one-component developer is applied through a flexible bias power supply unit. (3) In an electrophotographic image forming apparatus for forming an image on a recording medium in which a developing cartridge is detachable,
a) an electrophotographic photoreceptor, and b) a developer carrier for developing the latent image formed on the electrophotographic photoreceptor with the nonmagnetic one-component developer by rotating while carrying the non-magnetic one-component developer. A developer layer forming member that abuts on the developer carrier via the non-magnetic one-component developer so as to apply a thin layer of the non-magnetic one-component developer on the developer carrier; and A developer charge providing member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotational direction of the developer carrier with respect to the contact portion of the developer layer forming member with the developer carrier; A support member rotatably supporting the developer charge application member, a swing member for swingably holding the developer charge application member with respect to the developer carrier via the support member, and the swing member A swing support member for swingably supporting the The developer charge applying member that swings together with the swinging member against the developer carrier is provided with a discharge starting voltage with respect to the non-magnetic one-component developer layer thinly coated on the developer carrier. A mounting means for removably mounting the developing cartridge to which a bias having the same polarity as that of the non-magnetic one-component developer is applied via a flexible bias feeding means; and c) the non-magnetic one-component developer. Transfer means for transferring a developer image formed on the electrophotographic photoreceptor by one-component developer to the recording medium; and d) conveying means for conveying the recording medium. It is an electrophotographic image forming apparatus. (3-2): In an electrophotographic image forming apparatus for detachably attaching a developing cartridge and forming an image on a recording medium, a developing container containing a) an electrophotographic photosensitive member and b) a non-magnetic one-component developer. A latent image formed on the electrophotographic photosensitive member by rotating along with the non-magnetic one-component developer while extending along the longitudinal direction of the opening of the developing container, A developer carrier to be developed by a one-component developer, and the non-magnetic one-component developer via the non-magnetic one-component developer to the developer carrier so as to apply a thin layer of the non-magnetic one-component developer on the developer carrier. The developer layer forming member is in contact with the developer carrier of the developer layer forming member, and the developer carrier is in contact with the developer carrier on the upstream side in the rotation direction of the developer carrier. Developer application to supply and apply magnetic one-component developer And a developer charge applying member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotation direction of the developer carrier with respect to the contact portion of the developer layer forming member with the developer carrier. A support member rotatably supporting the developer charge application member, a swing member for swingably holding the developer charge application member with respect to the developer carrier via the support member, and A swing support member that swingably supports the swing member, wherein the developer charge applying member that swings together with the swing member against the developer carrying member includes the developer. A bias having a voltage equal to or higher than the discharge starting voltage and having the same polarity as the non-magnetic one-component developer is applied to the non-magnetic one-component developer layer thinly coated on the support via a flexible bias power supply unit. To attach removable developer cartridges Mounting means; c) transfer means for transferring a developer image formed on the electrophotographic photosensitive member by the non-magnetic one-component developer onto the recording medium; and d) transport means for transporting the recording medium. And an electrophotographic image forming apparatus comprising:

(Operation) In the developing device, the developing cartridge, and the electrophotographic image forming apparatus of the present invention, the developer charge applying member is driven by the developer carrier to rotate in the longitudinal direction of the developer carrier. At both ends, the non-magnetic one-component developer thinly coated on the developer carrier is electrically charged.

This makes it possible to reliably prevent the generation of an uncharged non-magnetic one-component developer at both ends in the longitudinal direction of the developer carrier, and to prevent the non-magnetic one-component developer from being applied to the developer carrier. A thin layer of the developer can be stably and favorably formed.

A bias having the same polarity as that of the non-magnetic one-component developer is applied to the developer charge applying member via a flexible bias power supply means.

Accordingly, the bias power supply means flexibly moves in response to the swing of the developer charge applying member, and reliably and stably supplies power to the developer charge applying member without hindering the movement of the developer charge applying member. It can be carried out.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color electrophotographic image forming apparatus as an electrophotographic image forming apparatus according to the present invention will be described below with reference to the drawings.

[Overall Description of Color Electrophotographic Image Forming Apparatus] First, the overall configuration of a color electrophotographic image forming apparatus will be schematically described with reference to FIG.

FIG. 1 is an explanatory view of the overall configuration of a color laser printer which is an embodiment of a color electrophotographic image forming apparatus.

The color laser printer according to the present embodiment has an image forming unit IM. The image forming unit IM includes a photosensitive drum 15 as an electrophotographic photosensitive member that rotates at a constant speed, and a fixed black developing device. 21B and three rotatable color developing devices (a yellow developing device 20Y and a magenta developing device 20) as a developing device or a developing cartridge.
M, cyan developing device 20C).

Below the image forming section IM, the developed and multi-transferred color image is held and further transferred to a transfer material 2 as a recording medium fed from a feeding section described later.
An intermediate transfer member 9 as a transfer unit is provided.

Then, the transfer material 2 on which the color image has been transferred
Is transferred to the fixing unit 25 to transfer the color image to the transfer material 2.
And is discharged to the discharge section 37 on the upper surface of the printer main body (electrophotographic image forming apparatus main body) P by the discharge rollers 34, 35, and 36. Here, the transfer material 2 is, for example, paper or an OHP sheet.

The rotatable color developing device 20
Y, 20M, 20C and fixed black developing device 21B
Are configured to be individually detachable from the printer main body P. Further, a transport unit 60 is configured by a feed roller 3, a feed roller 4, a retard roller 5 for preventing double feed, a feed guide 6, a transport roller 7, a registration roller 8, and discharge rollers 34, 35, and 36 described below. Have been.

Next, the configuration of each section of the electrophotographic image forming apparatus will be described.

[Electrophotographic Photoreceptor Unit] The electrophotographic photoreceptor unit 13 is integrally formed with a photoreceptor drum 15 and a cleaner container 14 of a cleaning device which also serves as a holder for the photoreceptor drum 15. The electrophotographic photoreceptor unit 13 is horizontally inserted into a unit storage portion from a mounting opening (not shown) provided in the printer main body P, and is attached to a mounting guide (not shown) as mounting means provided in the unit storage portion. It is supported detachably. As described above, the electrophotographic photosensitive member unit 13 is
, And is configured so that the unit can be easily replaced in accordance with the life of the photosensitive drum 15.

The photosensitive drum 15 according to the present embodiment is
An organic photoconductor layer is applied to the outside of an aluminum cylinder having a diameter of about 62 mm, and is rotatably supported by a cleaner container 14 of a cleaning device which also serves as a holder for the photosensitive drum 15.

A cleaning blade 16 and a primary charging means 17 are arranged on the periphery of the photosensitive drum 15, and the driving force of a drive motor (not shown) is transmitted to one end on the rear side in the figure, so that the photosensitive drum 15 is moved. It is rotated counterclockwise in the figure according to the image forming operation.

[Charging Means] The charging means 17 uses a contact charging method.
The surface of the photosensitive drum 15 is uniformly charged by applying a voltage to the charging roller.

[Exposure Means] Exposure to the photosensitive drum 15 is performed from a laser scanner unit 30. That is, when an image signal is given to a laser diode (not shown), the laser diode irradiates the polygon mirror 31 with image light corresponding to the image signal.

The polygon mirror 31 is rotated at a high speed by a scanner motor 31a, and the image light reflected by the polygon mirror 31 is converted into an image forming lens 32 and a reflection mirror 33.
The surface of the photoconductive drum 15 rotating at a constant speed is selectively exposed through the photoconductor 15, and as a result, an electrostatic latent image is formed on the photoconductive drum 15.

[Developing Means] The developing means 20 and 21 are provided for yellow, magenta,
It is composed of three rotary developing units 20Y, 20M, 20C and one black developing unit 21B that can develop each color of cyan and black.

The black developing device 21B is a fixed developing device, and has a developing sleeve 2 at a position facing the photosensitive drum 15.
1BS is at a very small interval (300 μ
m) and a reversal phenomenon (jumping phenomenon) corresponding to the electrostatic latent image on the photosensitive drum 15 is performed by applying a developing bias to the developing sleeve 21BS. Is visualized as a toner image.

The toner capacity of the black developing device 21B is determined in consideration of documents and image patterns to be handled by the user and the amount of toner consumption, and the rotary developing devices 20Y, 20Y, M (magenta) and C (cyan) of the other colors are used. It contains black toner equivalent to 15000 pages (A4, 5% printing), which is twice or more the toner capacity of 20M, 20C.

As described above, by increasing the capacity of the black developing device 21B, it is possible to reduce the frequency of replacement of the black developing device 21B by the user and to reduce the running cost per print.

As shown in FIG. 1, the arrangement of the black developing device 21B is such that the laser scanner unit 30 as an exposure device and the color developing devices 20Y, 20M, 20C of respective colors of Y, M, and C as rotary developing devices. To prevent the Y, M, and C toners from scattering to optical components such as the laser scanner unit 30 when the rotary developing units 20Y, 20M, and 20C for the respective colors rotate. I have. Accordingly, it is possible to prevent the toner from adhering to the polygon mirror 31, the imaging lens 32, the reflection mirror 33 and the like to hinder the electrostatic formation, and to obtain a clear output image.

Each of the three rotary developing devices 20Y, 20M, and 20C as the developing cartridge according to the present embodiment has a
Contains toner equivalent to page 00 (A4, 5% printing)
The developing rotary 23 that rotates around the shaft 22 is detachably held. The developing rotary 23 is provided with a mounting guide (not shown) as mounting means for removably mounting each of the rotary developing devices 20Y, 20M, and 20C.

At the time of image formation, each rotary developing device 20Y,
20M and 20C rotate around the shaft 22 while being held by the developing rotary 23. Then, of the rotary developing devices 20Y, 20M, and 20C, a predetermined rotary developing device 20
Y, 20M, and 20C stop at a position facing the photoconductor drum 15, and the rotary developing devices 20Y, 20M, and 20C are further stopped.
Developing sleeves 20YS, 20M as developer carrying members of C
S, 20CS are at a very small interval (30
(About 0 μm)
A visible image is formed corresponding to the electrostatic latent image on the photosensitive drum 15.

When a color image is formed, the developing rotary 23 rotates for each rotation of the intermediate transfer member 9 and the yellow developing device 20 rotates.
The developing process is performed in the order of Y, magenta developing device 20M, cyan developing device 20C, and then black developing device 21B.

In FIG. 2, the yellow rotary developing device 20Y
Shows a state in which it is positioned at a position facing the electrophotographic photosensitive member unit 13 and is stationary. This rotary developing device 2
In 0Y, the toner in the toner container 20a is sent to an application roller 20YR as a developer applying body by a stirring plate 20YA as a feeding mechanism. The developing roller 20 </ b> YB as a developer layer forming member pressed against the outer circumferences of the application roller 20 </ b> YR and the developing sleeve 20 </ b> YS rotating clockwise in the drawing,
A thin layer of toner is applied to the outer periphery of the YS, and a charge is applied to the toner (frictional charging).

A toner is developed on the photosensitive drum 15 in accordance with the latent image by applying a developing bias to the developing sleeve 20YS facing the photosensitive drum 15 on which the latent image is formed.

Magenta developing device 20M, cyan developing device 20
For C, toner development is performed by the same mechanism as described above.

Each of the rotary developing devices 20Y, 20M, 20C
Each of the developing sleeves 20YS, 20MS, and 20CS is connected to a high-voltage power supply for color development provided in the printer main body P and a driving unit when each of the rotary developing devices 20Y, 20M, and 20C is rotated to the developing position. In this case (none is shown), a voltage is sequentially and selectively applied for each color development, and the driving is connected.

[Intermediate Transfer Body] The intermediate transfer body 9 is provided with the rotary developing devices 20Y, 20M, 20C during the color image forming operation.
The toner image on the photosensitive drum 15 visualized by the above is subjected to multiple transfer four times (each image of four colors of Y, M, C, and B), so that the illustrated clock is synchronized with the outer peripheral speed of the photosensitive drum 15. It is rotating around. Further, the intermediate transfer body 9 that has undergone the multiple transfer is transferred to a transfer roller 10 to which a voltage is applied.
By carrying the transfer material 2 in between,
The toner images of the respective colors on the intermediate transfer body 9 are simultaneously multiplex-transferred onto the transfer material 2.

The intermediate transfer member 9 according to the present embodiment has a configuration in which the outer circumference of an aluminum cylinder 12 having a diameter of 186 mm is covered with an elastic layer 11 such as a medium resistance sponge or medium resistance rubber (see FIG. 1). This intermediate transfer body 9 is used for the printer body P
The gears are driven by a gear (not shown) which is rotatably supported and fixed integrally with the motor.

[Cleaning Means] The cleaning means is a photosensitive drum 15 by the developing means 20 and 21.
After the toner visualized on the photosensitive drum 15 is transferred to the intermediate transfer member 9, the toner remaining on the photosensitive drum 15 is cleaned. Thereafter, the cleaned waste toner is stored in the cleaner container 14. Cleaner container 14
The amount of waste toner stored in the cleaner container 14 does not fill the cleaner container 14 earlier than the life of the photosensitive drum 15. Therefore, the cleaner container 14 is simultaneously replaced when the life of the photosensitive drum 15 is replaced.

[Paper Feeding Unit] The paper feeding unit feeds the transfer material 2 to the image forming unit IM, and includes a cassette 1 containing a plurality of transfer materials 2, a feed roller 3, and a feed roller 4. , A retard roller 5 for preventing double feed, a paper feed guide 6, a transport roller 7, and a registration roller 8.

At the time of image formation, the paper feed roller 3 is driven and rotated in accordance with the image forming operation, separates and feeds the transfer material 2 in the cassette 1 one by one, and is guided by the paper feed guide 6 to form the transport roller 7. Registration roller 8 via
Leads to.

During the image forming operation, the registration roller 8
A non-rotational operation of causing the transfer material 2 to stand still and a rotation operation of transporting the transfer material 2 toward the intermediate transfer body are performed in a predetermined sequence. Align with.

[Transfer Section] As shown in FIG.
A swingable transfer roller 10 is provided as transfer means. The transfer roller 10 has a metal shaft (not shown) wound around a medium-resistance foamed elastic body, and is movable up and down in the figure and has a drive.

While forming the four-color toner image on the intermediate transfer member 9, that is, while the intermediate transfer member 9 is rotated a plurality of times, the transfer roller is not disturbed as shown by a solid line in the drawing. Reference numeral 10 is located below and is separated from the intermediate transfer member 9.

After the formation of the four color toner images on the intermediate transfer member 9, the transfer roller 10 is indicated by a thin line by a cam member (not shown) in accordance with the timing of transferring the color image onto the transfer material 2. Upper position, ie, transfer material 2
Is pressed against the intermediate transfer member 9 with a predetermined pressure. At this time, a bias is applied to the transfer roller 10 at the same time, and the toner image on the intermediate transfer body 9 is transferred to the transfer material 2.

Here, since the intermediate transfer member 9 and the transfer roller 10 are driven respectively, the transfer material 2 sandwiched between the two is subjected to the transfer step and at the same time at a predetermined speed in the left direction in the figure. The sheet is conveyed and sent to the fixing section 25 which is the next step.

[Fixing Unit] The fixing unit 25
0, 21 are transferred to the intermediate transfer body 9
Is to fix the toner image formed on the transfer material 2 through the. As shown in FIG. 1, a fixing roller 26 for applying heat to the transfer material 2 and the transfer material 2
And a pressure roller 27 for bringing the roller into pressure contact. Each of the rollers 26 and 27 is a hollow roller. Each roller 2
Each of the printers 6 and 27 has a heater 28 and 29 therein, and is configured to be driven to rotate and to simultaneously transfer the transfer material 2.

That is, the transfer material 2 holding the toner image is transported by the fixing roller 26 and the pressure roller 27, and the toner image is fixed to the transfer material 2 by applying heat and pressure.

[Configuration of Rotary Developing Unit] The configuration of each of the Y, M, and C rotary developing units 20Y, 20M, and 20C will be further described with reference to FIGS. 2 and 3 using the Y (yellow) color rotary developing unit 20Y as an example. It will be described in detail.

FIG. 2 is a schematic sectional view of the rotary developing device 20Y, and FIG. 3 is a schematic diagram of the rotary developing device 20Y viewed from the front (toward the photosensitive drum 15). In FIG. 3, the developing sleeve 20YS is not shown for convenience of explanation.

The rotary developing device 20Y includes a toner container 20a containing a yellow non-magnetic toner as a non-magnetic one-component developer, and an opening 38 for supplying the yellow non-magnetic toner to the developing sleeve 20YS. Developing container 20b having the same is joined by ultrasonic welding or the like.
, A developing sleeve 20YS, a developing blade 20YB, a coating roller 20YR, and the like are attached. The longitudinal direction of the opening 38 of the developing container 20b (the developing sleeve 20)
End seal members 39 are provided at both ends (in the axial direction of YS), and are pressed against the developing sleeve 20YS extending along the longitudinal direction of the opening 38 of the developing container 20b with a constant squeezing amount. Is prevented from leaking to the outside of both ends in the longitudinal direction of the opening 38. End sealing member 3
Reference numeral 9 denotes a two-layer structure in which the surface layer in contact with the developing sleeve 20YS is made of Teflon felt or Teflon pile, and the lower layer of the surface layer is made of an elastic material such as wool felt or Polon. The developing blade 20YB is made of a metal thin plate of SUS or phosphor bronze having a spring elasticity, and a rubber material is adhered or molded on a contact surface side with the developing sleeve 20YS. Coating roller 20YR
Is an elastic roller provided with a polyurethane foam on a metal core, is formed shorter in the longitudinal direction than the opening 38 of the developing container 20b, and is rotatably supported by the developing container 20b. The developing sleeve 2 is located upstream of the developing blade 20YB in the rotation direction of the developing sleeve 20YS.
In contact with OYS, toner is supplied to the developing sleeve 20YS and undeveloped toner is peeled off.

As shown in FIG. 3, the developing blade 20YB has a longitudinal direction (axial direction of the developing sleeve 20YS).
The developing sleeve 2 whose both ends 20YB1 are indicated by hatched portions in the figure.
It has an oblique cut shape so that the distance l (ell) from the contact nip portion N with 0YS to the tip end 20YB2 of the developing blade 20YB is continuously shortened, and is further formed at both ends (oblique cut shape portions) 20YB1. Developing blade 20
The shortest position of the tip 20YB2 of the YB is configured to be within the contact nip portion N. Generally, the thickness of the toner layer formed on the developing sleeve 20YS is a point N2 on the upstream side in the rotation direction of the developing sleeve 20YS of the contact nip portion N.
The length of the toner layer formed on the developing sleeve 20YS increases with an increase in the distance l, and the thickness of the toner layer decreases with a decrease in the distance l. In the present embodiment, compared to this distance 1 (ell) in the normal developing area of the developing sleeve 20YS, the end 2
0YR1 and the developing blade 2 on the peripheral surface of the developing sleeve 20YS corresponding to the non-contact portion with the application roller 20YR.
Area where 0YB contacts (area corresponding to 20YB1)
Thus, by continuously shortening the distance 1 (ell), the regulating force on the toner in the area is increased. That is, the oblique cut portions 2 are formed at both ends in the longitudinal direction of the developing blade 20YB.
0YB1, the developing blade 20YB
Of the toner in the longitudinal direction at both ends thereof is formed, and a thin layer of toner can be formed in the above-mentioned region.

The toner is a non-magnetic one-component developer, is excellent in transferability, and cleans the untransferred toner remaining on the photosensitive drum 15 without being transferred by the above-described cleaning means such as the cleaning blade 16 and fur brush. In this case, since the lubricating property is high, there is an advantage that abrasion of the photosensitive drum 15 is small. That is, a toner having a spherical shape and a smooth surface is used as the toner. Specifically, as a shape factor, SF-1 is 100
１８０180 and SF-2 of 100〜140. These SF-1 and SF-2 are Hitachi F
Using E-SEM (S-800), a toner image
00 are sampled, the image information is introduced into an image analysis device (Luzex3) manufactured by Nicole via an interface, analyzed, and a value calculated by the following equation is defined.

SF-1 = (MXLNG) ² / AREA
× π / 4 × 100 SF-2 = (PERI) ² / AREA × π / 4 × 10
0 (MXLNG: toner projection area, AREA: absolute maximum length, PERI: circumference) The shape factor SF-1 of this toner indicates a spherical degree, and is 10
As the size increases from 0, the shape gradually changes from a spherical shape to an irregular shape. SF-2 indicates the degree of unevenness. As the value increases from 100, the unevenness on the surface of the toner becomes remarkable.

During the developing operation, the toner in the toner container 20a is sent to the coating roller 20YR of the developing container 20b by the rotation of the stirring plate 20YA. And the application roller 2
0YR rotates in the direction of the arrow to cause the developing sleeve 2 to rotate.
0YS, and is applied to the application roller 20Y at a contact portion T between the developing sleeve 20YS and the application roller 20YR.
The toner carried on R is frictionally charged by being rubbed with the developing sleeve 20YS, and adheres to the developing sleeve 20YS. Then, the developing sleeve 20YS
Is sent under the pressure contact of the developing blade 20YB with the rotation of the developing blade 20YB, receives an appropriate tribo (amount of triboelectric charge) and forms a thin layer on the developing sleeve 20YS.

[Structure of Developer Charge-Applying Roller (Developer Charge-Applying Member)] Here, the developer charge-applying roller 40 as a developer charge-applying member for applying electric charge to the toner is used.
(Hereinafter, simply referred to as “charge applying roller”) will be described. As shown in FIG. 2, the charge applying roller 40 is rotated by the developing blade 20YB in the rotation direction of the developing sleeve 20YS.
Abutting portion of the developing sleeve 20YS (abutting nip portion N)
More specifically, on the downstream side of the developing sleeve 20YS in the rotational direction of the developing sleeve 20YS, the toner on the developing sleeve 20YS contacts the developing sleeve 20YS on the upstream side of the developing section Q for developing the electrostatic latent image on the photosensitive drum 15. The toner formed in a thin layer is electrically charged while being driven and rotated by the developing sleeve 20YS.

FIG. 4 is a front view (toward the photosensitive drum 15) of the rotary developing device 20Y to which the charge applying roller 40 is attached.
FIG. 5 is a perspective view showing a state in which the charge applying roller 40 is attached.

As shown in FIGS. 4 and 5, the charge applying roller 40 is rotatably supported by a roller support shaft 41 as a support member, and is in contact with the developing sleeve 20YS. The roller support shaft 41 is provided on the cylindrical portion 4 of the swing member 42.
2a is fitted and penetrated. The swing member 42 is a swing support plate 43 as a swing support member (or an electrode plate support member).
The charge applying roller 40 is swingably supported in the direction of arrow B by a pressure member (pressure spring) 44 so that the charge application roller 40 is brought into contact with the surface of the developing sleeve 20YS at about 70 gf to 150 gf. A coil spring 45 as a flexible bias supply means is fitted to an end 41 a of the roller support shaft 41 opposite to the side supporting the charge applying roller 40, and is disposed on the swing support plate 43. It is connected to the electrode plate 46.

As shown in FIG. 4, the charge applying roller 40 has a non-toner coated portion A2 on the developing sleeve 20YS.
It is in contact with both of the toner coat portions A1. This is because, due to the high fluidity of the toner, the charge applying roller 40 is likely to slip when only the toner coat portion A1 contacts, and there is a possibility that the driven rotation cannot be obtained. For driving, the driven or same peripheral speed is essential between the charge applying roller 40 and the developing sleeve 20YS.
0, if a peripheral speed difference occurs between the developing sleeves 20YS, the toner coat becomes non-uniform, causing toner transfer to the photosensitive drum 15 as a fog at the time of development, and scattering or leakage of the toner.

As shown in FIG. 6, the charge applying roller 40 has an end 20YR1 of the application roller 20YR, and an opening 3 of the application roller 20YS and the developing container 20b.
8 includes an area of the gap c with the side wall 38a in the longitudinal direction as a contact area with the developing sleeve 20YS. The reason for setting the contact area of the charge applying roller 40 as described above is as follows.
Area without coating roller 20YS and coating roller 2
In the end portion 20YR1 of 0YR, an area where the amount of triboelectric charge for the toner becomes insufficient,
This is because the electric adhesion (mirror power) to S is weak.

Further, the charge applying roller 40 includes oblique cut portions 20YB1 formed at both ends in the longitudinal direction of the developing blade 20YB as a contact area with the developing sleeve 20YS.

In the present embodiment, the charge applying roller 40 including the above-mentioned contact area is provided at both ends in the longitudinal direction of the developing sleeve 20YS, so that the toner is in the vicinity of both ends 20YB1 in the longitudinal direction of the developing blade 20YB. The developing blade 20 </ b> YB is lifted up by being sandwiched between the contact nip portions N, and the toner layers at both ends in the longitudinal direction of the contact nip portions N are gradually thickened in a streak shape, so that the electric adhesion to the developing sleeve 20 </ b> YS is Even if it is lowered, the electric adhesion of the toner to the developing sleeve 20YS is restored by the electric charge applied to the toner by the charge applying roller 40, and the toner is transferred to the photosensitive drum 15 as fog, or the toner is transferred to the developing sleeve 20YS. So-called toner leakage, which spills from the surface of the printer to the outside and significantly contaminates the inside of the printer body P Door can be.

The end 20Y of the application roller 20YR
R1 and the longitudinal side wall 3 of the opening 38 of the developing container 20b
Even when the amount of triboelectric charge for the toner becomes insufficient in the area of the gap c between the developing roller 20a and the electric adhesion to the developing sleeve 20YS, the electric charge is applied to the toner by the electric charge applying roller 40. The electrical adhesion to the developing sleeve 20YS is restored, and toner leakage can be prevented.

As a result, generation of uncharged toner at both ends in the longitudinal direction of the developing sleeve 20YS can be reliably prevented, and a thin layer of toner can be stably and favorably formed on the developing sleeve 20YS. it can.

[Description of Assembling and Release of Contact of Roller] The assembly of the charge roller 40 to the rotary developing device 20Y will be described with reference to FIGS. The charge applying roller 40 is a roller support shaft 4
1. Attached to the oscillating support plate 43 together with the oscillating member 42, the pressing member 44, and the like to form a unit as a charge applying roller unit D. The blade stay as a support sheet metal for the rotary developing device 20Y It is designed to be attached to a sheet metal 48. After the developing sleeve 20YS is supported by the developing container 20b, the charge applying roller unit D is a double-sided tape from the front (in the direction of the photosensitive drum 15) on a blade stay sheet metal 48 that supports the developing blade 20YB and is attached to the developing container 20b. It is attached by gluing or screwing. At this time, the charge applying roller 40 is pressed against the developing sleeve 20YS by a pressing member (pressing spring) 44 for pressing the developing sleeve 20YS with a predetermined pressure, as shown in FIG. At a position (a solid line position shown in FIG. 12) that is further rotated upstream from a predetermined contact position (a first position (a two-dot chain line position shown in FIG. 12)). When the charge applying roller unit D is to be attached to the blade stay sheet metal 48, the charge applying roller 40 is connected to the developing sleeve 2 as shown by a solid line in FIG.
Developing sleeve 20YS from a predetermined contact position on
Will fall to the upstream side in the rotation direction. In this state, the charge applying roller 40 is not driven to rotate with respect to the developing sleeve 20YS, resulting in poor rotation. Furthermore, parts such as the roller support shaft 41 may be deformed or damaged. In order to avoid such a situation, even if the charge applying roller 40 falls to the upstream side in the rotation direction of the developing sleeve 20YS during the assembly as described above, the charge applying roller 40 escapes from the developing sleeve 20YS to abut. It is necessary to once release and to move the charge applying roller 40 to a predetermined contact position to make contact with the developing sleeve 20YS. Furthermore, it is preferable that the charge applying roller 40 is attached without being in contact with the developing sleeve 20YS.

Therefore, in the present embodiment, the swing member 42
And a lever portion 42b as an operating portion for rotating the charge applying roller 40 in a direction to escape from the surface of the developing sleeve 20YS. The lever 42b is operated as follows. The charge applying roller unit D is attached, and the charge applying roller 40 is attached to the developing sleeve 20YS.
13, the lever 42b of the swinging member 42 is pushed as shown in FIG. 13, and the swinging member 42 is pressed by the charge applying roller 40 to the developing sleeve 20Y.
S to the developing sleeve 2
Position where the contact with 0YS is temporarily released (second position)
Then, the charge applying roller 40 is moved. After that, the lever portion 42b is released, and the charge applying roller 40 is normally brought into contact with the developing sleeve 20YS. Alternatively, as shown in FIG. 14, when attaching the charge applying roller unit D to the blade stay sheet metal 48, the lever portion 42b of the swing member 42 is pressed in advance so that the charge applying roller 40 does not contact the developing sleeve 20YS. After being attached to the blade stay sheet metal 48, the lever portion 42b is released to bring the charge applying roller 40 into contact with the developing sleeve 20YS.

As described above, in the present embodiment, the charge applying roller 40 is attached to the swing support plate 43 together with the roller support shaft 41, the swing member 42, the pressing member 44, and the like to form a unit as the charge applying roller unit D. By that
This improves the assemblability of the charge applying roller 40.

The charge applying roller 40 can be moved from a predetermined contact position (first position) in contact with the developing sleeve 20YS to a position (second position) in which the contact with the developing sleeve 20YS is released. In addition, since the charge applying roller 40 is swingably supported by the swing support plate 43 via the roller support shaft 41 and the swing member 42, the charge applying roller 40 is stably and surely positioned at a predetermined contact position with respect to the developing sleeve 20YS. It is possible to assemble, the electric charge is stably and reliably applied to the toner by the charge applying roller 40, and toner leakage can be prevented.

[Description of bias application to developer charge applying roller]
(See FIG. 7), an AC voltage (developing AC bias) obtained by superimposing a DC applied between both the developing sleeve 20YS and the photosensitive drum 15 is branched, and is applied by an equivalent circuit as shown in FIG. The waveform of the bias applied to the developing sleeve 20YS and the charge applying roller 40 is as shown in FIG. 8, and when the toner pull-back bias is applied, the potential difference between the developing sleeve 20YS and the charge applying roller 40 becomes 1
The capacitors C1 and C2 in FIG.
The capacity of C2 is adjusted.

The bias applied to the charge applying roller 40 after being branched as described above is applied to the coil spring 4 by the electrode plate 46 disposed on the swing support plate 43 shown in FIGS.
5 is applied to the charge applying roller 40 via the oscillating roller support shaft 41 and the bearing inside the charge applying roller 40. Here, since the coil spring 45 having flexibility is used as a bias supply unit to the swinging roller support shaft 41, the coil spring 45 is flexibly deformed in response to the swing of the charge applying roller 40, and Power can be supplied stably and reliably without hindering swinging.

In the present embodiment, the bias applied to the developing sleeve 20YS is a DC voltage: Vdc =
AC at −300 V: square wave Vpp = 2200 V, f = 2
200 Hz is superimposed. Charge applying roller 4
The bias applied to 0 has the same polarity as the toner, and the DC voltage: Vdc = -900 V and the AC: rectangular wave Vpp = 1
000 V, f = 2200 Hz. Further, there is no phase difference between the bias applied to the developing sleeve 20YS and the bias applied to the charge applying roller 40.

The volume resistance of the charge applying roller 40 is 10 ⁸
A to 10 ⁹ [Omega] cm, the discharge starting voltage with uncharged toner in the toner of the developing sleeve 20YS and the charge imparting roller 40 is not less than 1200 V. Therefore, the capacitance of the capacitor C2 in FIG. 7 is adjusted so that the potential difference between the developing sleeve 20YS and the charge applying roller 40 when the toner pull-back bias is applied becomes 1200 V or more.

[Description of Capacitor C2] Here, the capacitor C2 will be described. FIG. 15 shows the rotary developing device 2
FIG. 16 is a detailed sectional view of the vicinity of the charge applying roller portion of 0Y, and FIG. The capacitor C2 is formed between a blade stay metal plate 48 set to the same potential as the developing bias and an electrode plate 46 located on the blade stay metal plate 48. As described above, the blade stay sheet metal 48 and the electrode plate 46 have different potentials from the developing bias and the charge applying roller bias, respectively, and face each other. Therefore, if the capacitance of the capacitor formed by these two sheet metals 48 and 46 is large, Mutual voltages interfere with each other. Therefore, the developing bias becomes dull (rise of voltage), the waveform does not become clear as shown in FIG. 8, and uniform development is not performed. In such a case, there is a risk of adverse effects such as a thinned image. Similarly, since the predetermined voltage is not uniformly applied to the charge applying roller 40, the toner is not sufficiently discharged.

Therefore, it is necessary to reduce the capacitance of the capacitor C2. In order to reduce the capacitance of the capacitor C2, there is a method of increasing the distance d between the blade stay sheet metal 48 and the electrode plate 46 facing the blade stay sheet metal 48, or reducing the area S of the facing electrode plate 46. , The area S is reduced. Specifically, as shown in FIG. 16, the electrode plate 46 is disposed on the swing support plate 43 so as to be vertically set with respect to the blade stay 48. This allows
The surface of the electrode plate 46 facing the blade stay sheet metal 48 is equal to the thickness, and the width of the electrode plate 46 is minimized at a level that can be processed, and is disposed on the swing support plate 43 so as to be parallel to the blade stay sheet metal 48. The area S can be reduced, and the capacitance of the capacitor C2 can be significantly reduced.

Further, the capacity of the capacitor C2 is reduced,
Since the interference between the developing bias and the charge applying roller 40 is reduced, there is no adverse effect on the image such as low density, and the charge applying roller applies a predetermined bias to reliably discharge the toner sufficiently. be able to.

As shown in FIGS. 15 and 16, the swing support plate 46 on which the electrode plate 46 is disposed is
6 and blade stay sheet metal 48,
The dielectric constant ε of the material of the swing support plate 43 is also equal to the capacitance of the capacitor C2.
Affect the capacity of If the permittivity ε of the swing support plate 43 is small, the capacity of the capacitor C2 is small. For example, the material of the swing support plate 43 is a resin material having high insulation, that is, a conductive material such as carbon is used as the resin material. Those not included are good. Usually, besides making the resin material conductive,
When the resin material is colored black, the resin material is colored by dispersing the carbon-based material. Therefore, in the present embodiment, non-conductive and non-black colored, specifically, white polystyrene (PS) resin is used. Since all resin materials are basically insulative, any material other than PS resin may be used as long as it is white.

The swing support plate 43 is provided on the developing sleeve 20.
A rib 43a is provided in the longitudinal direction near the developing sleeve 20YS so as to cover the developing sleeve 20YS. This is because the developing sleeve 20Y
This is to prevent the toner that floats and scatters from the developing sleeve 20YS due to the rotation of the S from contaminating the electrode plate 46, the contact portion of the electric circuit, and the upper black developing device 21B itself. It regulates the upward flow.

As described above, the developing sleeve 20
The thin toner layer formed on the YS is developed as a toner image on the electrostatic latent image on the photosensitive drum 15. The undeveloped toner that has not been consumed is collected into the developing container 20b with the rotation of the developing sleeve 20YS (see FIG. 2). As shown in FIG. 2, a flexible sheet member 47 is provided below the developing sleeve 20YS, and the undeveloped toner is
0b, and prevents the toner in the developing container 20a from leaking. The collected undeveloped toner is peeled off from the surface of the developing sleeve 20YS at a contact portion T between the application roller 20YR and the developing sleeve 20YS. Most of the stripped undeveloped toner is conveyed along with the rotation of the application roller 20YS and is transported to the developing container 20b.
Mixed with the toner inside, and the charge of the toner is dispersed.
At the same time, new toner is supplied onto the developing sleeve 20YS by the rotation of the application roller 20YR, and the above operation is repeated.

[Other Embodiments] In the above-described embodiment, the yellow developing device 20Y is exemplified as the developing device or the developing cartridge. However, the developing device or the developing cartridge of the present invention is not limited to this. The same configuration can be adopted in the developing device 20M and the cyan developing device 20C.

The developing blade 20YB in which the oblique cut portions 20YB1 are formed at both ends in the longitudinal direction has been exemplified.
For example, a developing blade without an oblique cut portion can be used. In this case, the developing blade is lifted by the toner being sandwiched between the contact nip portions N near the longitudinal end of the developing blade, and the toner layers at both ends in the longitudinal direction of the contact nip portion N are gradually thickened in a streak shape. Therefore, even if the electric adhesion to the developing sleeve 20YS is reduced,
The electric charge applied to the toner by the charge applying roller restores the electrical adhesion to the developing sleeve, causing the toner to transfer to the photoreceptor drum as fog, and the toner spilling out of the surface of the developing sleeve to the printer body. It is possible to prevent so-called toner leakage that significantly contaminates the inside.

[0098]

As described above, according to the developing device, the developing cartridge, and the electrophotographic image forming apparatus of the present invention, the developer is provided while the developer charging member is rotated by the developer carrier. Since the non-magnetic one-component developer thinly coated on the developer carrier is electrically charged at both ends in the longitudinal direction of the carrier, the uncharged non-magnetic monocomponent developer is electrically charged at both longitudinal ends of the developer carrier. The generation of the component developer can be reliably prevented, and a thin layer of the non-magnetic one-component developer can be stably and favorably formed on the developer carrier.

Further, a bias having the same polarity as that of the non-magnetic one-component developer is applied to the developer charge applying member via a flexible bias power supply means, so that the developer charge applying member is prevented from swinging. A bias can be reliably applied to the developer charge applying member without hindering the movement of the developer charge applying member.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a color laser printer as an electrophotographic image forming apparatus according to an embodiment.

FIG. 2 shows a developing device (developing cartridge) of the present embodiment.
Schematic cross-sectional configuration diagram of

FIG. 3 shows a developing device (developing cartridge) of the present embodiment.
Schematic configuration view from the front

FIG. 4 is a front view showing a part of a developing device (developing cartridge) in a state where a developer charge applying roller is attached.

FIG. 5 is a perspective view showing a part of a developing device (developing cartridge) showing a state in which a developer charging roller is attached.

FIG. 6 is a front view showing a part of a developing device (developing cartridge) in a state where a developer charge applying roller is attached.

FIG. 7 is an equivalent circuit diagram in the developing device of the embodiment.

FIG. 8 is a waveform diagram of a bias applied to the developing device of the embodiment.

FIG. 9 is a schematic cross-sectional configuration diagram of a conventional developing device.

FIG. 10 is a front view of an example of a conventional developing device.

FIG. 11 is a front view of another example of the conventional developing device.

FIG. 12 is a diagram illustrating a state in which a developer charge applying roller is dropped into an upstream side in a rotation direction of a developing sleeve and is assembled in the developing device according to the exemplary embodiment;

FIG. 13 is a diagram illustrating a state in which the contact of the developer charge applying roller with the developing sleeve is released in the developing device according to the exemplary embodiment;

FIG. 14 is a diagram illustrating an example in which a developing image charge applying roller unit is attached without abutting on a developing sleeve in the developing device of the present embodiment.

FIG. 15 is a detailed view of a portion where a developed image charge applying roller is arranged in the developing device of the exemplary embodiment.

FIG. 16 is a configuration diagram and a model diagram of a capacitor constituting an equivalent circuit in the developing device of the present embodiment.

[Explanation of symbols]

2 Transfer Material (Recording Medium) 9 Intermediate Transfer Body (Transfer Means) 15 Photoconductor Drum (Electrophotographic Photoconductor) 20Y Rotary Developing Device (Developing Apparatus or Developing Cartridge) 20b Developing Container 20YS Developing Sleeve (Developer Carrier) 20YB Development Blade (developer layer forming member) 20YR Coating roller (developer coated body) 38 Opening 40 Developer charge applying roller (developer charge applying member) 41 Roller support shaft (support member) 42 Swing member 43 Swing support plate (Swinging support member) 45 Coil spring (flexible bias power supply means) 60 Transport means N Contact nip portion (contact portion)

Continued on the front page F-term (reference) 2H071 DA08 EA10 2H073 AA10 BA02 BA15 BA25 2H077 AC04 AD02 AD06 AD13 AD17 AD35 AE02 AE08 CA11 EA14

Claims (14)

[Claims] 1. A developer carrier for developing a latent image formed on an electrophotographic photosensitive member by the nonmagnetic one-component developer by supporting and rotating a non-magnetic one-component developer, and the developer A developer layer-forming member that contacts the developer carrier via the non-magnetic one-component developer so as to apply a thin layer of the non-magnetic one-component developer on a carrier; and A developer charge providing member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotational direction of the developer carrier with respect to a contact portion with the developer carrier, and A support member rotatably supporting, a swing member for swingably holding the developer charge applying member with respect to the developer carrying member via the support member, and a swing member for swingably supporting the swing member. A swing support member, and The developer charge applying member that swings and contacts with the swing member is at a discharge starting voltage or higher with respect to the non-magnetic one-component developer layer thinly coated on the developer carrier, and A developing device, wherein a bias having the same polarity as that of the non-magnetic one-component developer is applied via a flexible bias feeding unit. 2. The developing device according to claim 1, wherein said flexible bias power supply means is a coil spring. 3. The flexible bias power supply means is a coil spring, and the coil spring as the flexible bias power supply means is fitted on the support member and supplies power to the developer charge applying member. The developing device according to claim 1. 4. A developing container containing a non-magnetic one-component developer, extending along a longitudinal direction of an opening of the developing container, and rotating while carrying the non-magnetic one-component developer. A developer carrying the latent image formed on the electrophotographic photoreceptor by the non-magnetic one-component developer; and developing the non-magnetic one-component developer by applying a thin layer on the developer carrying body. A developer layer forming member that contacts the developer carrier via the non-magnetic one-component developer; and a rotation of the developer carrier relative to a contact portion of the developer layer forming member with the developer carrier. A developer application body for supplying and applying the non-magnetic one-component developer in contact with the developer carrier on the upstream side in the direction; and a contact portion of the developer layer forming member with the developer carrier. On the other hand, on the downstream side in the rotation direction of the developer carrier, A developer charge application member that abuts both ends of the developer charge application member, a support member that rotatably supports the developer charge application member, and swings the developer charge application member with respect to the developer carrier via the support member. A swing member for movably holding the swing member, and a swing support member for swingably supporting the swing member, wherein the swing member abuts on the developer carrying member together with the swing member. The developer charge applying member has a bias equal to or higher than the discharge start voltage with respect to the non-magnetic one-component developer layer applied thinly on the developer carrier, and having the same polarity as the non-magnetic one-component developer. A developing device which is applied through a flexible bias power supply. 5. The developing device according to claim 4, wherein said flexible bias power supply means is a coil spring. 6. The flexible bias power supply means is a coil spring, and the coil spring as the flexible bias power supply means is fitted to the support member to supply power to the developer charge applying member. The developing device according to claim 4, wherein 7. A developing cartridge detachably mountable to the main body of an electrophotographic image forming apparatus, wherein a latent image formed on an electrophotographic photosensitive member is rotated by carrying a non-magnetic one-component developer. A developer carrier to be developed by a developer, and abutting on the developer carrier via the nonmagnetic one-component developer so as to apply a thin layer of the nonmagnetic one-component developer on the developer carrier. A developer layer-forming member, and a contact portion between the developer layer-forming member and the developer carrier that is in contact with both ends in the longitudinal direction of the developer carrier on the downstream side in the rotation direction of the developer carrier. A developer charge application member, a support member rotatably supporting the developer charge application member, and a swing member for swingably holding the developer charge application member with respect to the developer carrier via the support member. A moving member, and the swing member A swing support member that swingably supports the developer charge applying member, which swings together with the swing member with respect to the developer carrier, and abuts on the developer carrier. A bias having a voltage equal to or higher than the discharge starting voltage and having the same polarity as that of the non-magnetic one-component developer is applied to the thinly applied non-magnetic one-component developer layer through a flexible bias power supply unit. A developing cartridge characterized by the following. 8. The developing cartridge according to claim 7, wherein said flexible bias power supply means is a coil spring. 9. The flexible bias power supply unit is a coil spring, and the coil spring as the flexible bias power supply unit is fitted to the support member and supplies power to the developer charge applying member. The developing cartridge according to claim 7, wherein 10. A developing cartridge detachably mountable to an electrophotographic image forming apparatus main body, comprising: a developing container containing a non-magnetic one-component developer; and a developing container extending along a longitudinal direction of an opening of the developing container. A developer carrier for developing the latent image formed on the electrophotographic photoreceptor by the nonmagnetic one-component developer by supporting and rotating the non-magnetic one-component developer; and A developer layer forming member that contacts the developer carrier via the nonmagnetic one-component developer so as to apply a thin layer of the nonmagnetic one-component developer; and the developer carrier of the developer layer-forming member A developer application member for supplying and applying the non-magnetic one-component developer by abutting the developer carrier on the upstream side in the rotation direction of the developer carrier with respect to the contact portion with the developer layer; Contact of the forming member with the developer carrier A developer charge applying member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotation direction of the developer carrier, a support member that rotatably supports the developer charge application member, A swing member that swingably holds the developer charge applying member with respect to the developer carrier via the support member, and a swing support member that swingably supports the swing member. The developer charge applying member that swings together with the swinging member with respect to the developer carrier is in contact with the nonmagnetic one-component developer layer thinly coated on the developer carrier. A developing cartridge, wherein a bias having a voltage equal to or higher than a discharge starting voltage and having the same polarity as that of the non-magnetic one-component developer is applied via a flexible bias power supply unit. 11. The developing cartridge according to claim 10, wherein said flexible bias power supply means is a coil spring. 12. The flexible bias power supply means is a coil spring, and the coil spring as the flexible bias power supply means is fitted to the support member to supply power to the developer charge applying member. The developing cartridge according to claim 10, wherein 13. An electrophotographic image forming apparatus for detachably attaching a developing cartridge and forming an image on a recording medium, comprising: a) an electrophotographic photosensitive member; and b) a non-magnetic one-component developer carried and rotated. A developer carrier for developing the latent image formed on the electrophotographic photoreceptor with the non-magnetic one-component developer; and applying a thin layer of the non-magnetic one-component developer on the developer carrier. A developer layer forming member that comes into contact with the developer carrying member via the non-magnetic one-component developer; and the developer carrying member contacts a contact portion of the developer layer forming member with the developer carrying member. A developer charge providing member that abuts on both ends in the longitudinal direction of the developer carrier on the downstream side in the rotation direction of the body, a support member rotatably supporting the developer charge providing member, and the developer charge providing member. The current through the support member A swing member that swingably holds the image material carrier, and a swing support member that swingably supports the swing member, together with the swing member with respect to the developer carrier. The developer charge applying member that oscillates and comes into contact with the non-magnetic one-component developer layer thinly coated on the developer carrier at a discharge starting voltage or higher and the non-magnetic one-component development Mounting means for removably mounting a developing cartridge to which a bias having the same polarity as the developer is applied via a flexible bias feeding means; and c) the electrophotographic photosensitive member using the non-magnetic one-component developer. An electrophotographic image forming apparatus, comprising: a transfer unit for transferring the developer image formed on the recording medium to the recording medium; and d) a conveying unit for conveying the recording medium. 14. An electrophotographic image forming apparatus for forming an image on a recording medium in which a developing cartridge is detachable, comprising: a) an electrophotographic photoreceptor; and b) a developing container containing a non-magnetic one-component developer. The latent image formed on the electrophotographic photosensitive member extends along the longitudinal direction of the opening of the developing container, and carries the non-magnetic one-component developer to rotate the latent image formed on the electrophotographic photosensitive member. A developer carrier developed with a component developer, and a non-magnetic one-component developer applied to the developer carrier via the non-magnetic one-component developer so as to apply a thin layer of the non-magnetic one-component developer on the developer carrier. A developer layer forming member that is in contact with the developer carrier, and a non-magnetic member that contacts the developer carrier at a rotation direction upstream side of the developer carrier with respect to a contact portion of the developer layer forming member with the developer carrier. Development to supply and apply one-component developer An application body, and a developer charge that abuts on both ends in the longitudinal direction of the developer carrier at a downstream side in the rotation direction of the developer carrier with respect to a contact portion of the developer layer forming member with the developer carrier. An application member, a support member rotatably supporting the developer charge application member, and a swing member for swingably holding the developer charge application member with respect to the developer carrying member via the support member. A swing support member that swingably supports the swing member; and wherein the developer charge applying member that swings together with the swing member against the developer carrier and contacts the developer carrier. For the non-magnetic one-component developer layer thinly coated on the developer carrier, a bias that is equal to or higher than the discharge starting voltage and has the same polarity as the non-magnetic one-component developer is supplied via a flexible bias power supply unit. The developing cartridge to be applied C) transfer means for transferring a developer image formed on the electrophotographic photosensitive member by the non-magnetic one-component developer onto the recording medium; and d) transporting the recording medium. An electrophotographic image forming apparatus, comprising: