JPH0675469A - One-component developing device - Google Patents

Abstract

PURPOSE:To restrain troubles such as the accumulation of the toner on the developing sleeve, the deterioration of the toner and the filming of the toner, and to obtain the excellent image without fogging and splashing by allowing excess toner held in a developing sleeve and then submitted for development to easily separate from the sleeve even after repetitively forming an image many times, thereby keeping a toner carrying amount to a developing area and the electrification of the toner appropriate in a one-component developing device. CONSTITUTION:A destaticizing member 19 abutting on the surface of the developing sleeve 2 of the one-component developing device is provided in an area leading to a toner regulating blade 4 from the downstream side of the developing area in the moving direction of the surface of the sleeve 2, and the surface of the member 19 abutting on the sleeve 2 is formed of a material more biased to the same polarity side as the regular electrification polarity of the toner than the toner in terms of electrification system, and a material excellent in conductivity is dispersed in the material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image formed on an electrostatic latent image carrier into a visible image in an image forming apparatus such as a copying machine or a printer. In particular, the toner supplied to the developer carrier whose surface is moving is passed between the toner regulating member that is in contact with the surface and the surface to hold it as a thin layer of charged toner and convey it to the developing area. The present invention relates to a one-component developing device that is used for development and returns to the toner supply side while retaining the excess toner remaining without being consumed after the development.

[0002]

2. Description of the Related Art The outline of an example of such a one-component developing device is shown in FIG. That is, the developing device of FIG. 9 includes a driving roller 91 which is rotationally driven in the CCW direction in the drawing by a driving unit (not shown), and the driving roller 91 has a flexible developing sleeve having an inner diameter slightly larger than the outer diameter of the roller. 92 is externally fitted, and both ends of the sleeve are pressed against the driving roller 91 from the back by the pressing guides 93, while the slack portion 920 formed on the opposite side by the pressing is an electrostatic latent image carrier. (Photosensitive drum in this example) It is in flexible contact with the PC. The developing sleeve 92 has a pressing guide 93.
The toner regulation blade 94 is in contact with the same side.

Behind the developing sleeve 92 is a buffer chamber 9
5, there is a toner supply chamber 96 behind it, a toner supply rotating member 97 (CCW direction rotation) in the buffer chamber 95, and a toner stirring / supply rotating member 98 (clockwise CW rotation) in the toner supply chamber 96. Are arranged respectively.
Further, on the lower surface of the developing sleeve 92, the buffer chamber 95
The lower seal member 99 is in contact with the toner to prevent the toner from leaking to the outside.

According to this developing device, the toner T sent from the toner supply chamber 96 to the buffer chamber 95 by the rotation of the rotary member 98 is sequentially developed in the developer supply region by the rotation of the toner supply rotary member 97. It is supplied to the surface of the sleeve 92. On the other hand, the sleeve 92 is rotated by the driving rotation of the driving roller 91 by a frictional force, and the toner T supplied thereto is passed between the toner regulating blade 94 and the photoconductor drum PC to cause the blade 94 to move. Is triboelectrically charged under a pressure of, and is formed into a thin layer having a predetermined thickness, is held on the sleeve surface, and is conveyed to a developing area facing the photosensitive drum PC, where it is statically developed under a developing bias V _B by a power source 921. It is used for developing an electrostatic latent image.

Excessive toner T after development is accompanied by the rotation of the sleeve 92, and the seal member 99 and the photosensitive drum P are in the middle of the process.
It is returned to the buffer chamber 95 through the space between C and C. The toner returned to the buffer chamber 95 is separated from the sleeve 92, but a part of the highly charged toner remains on the surface of the sleeve 92. The remaining toner forms a micro electric field with the sleeve 92, and this electric field also attracts the toner to be supplied next to the sleeve surface.

[0006]

However, for example, when the fluidity of the toner is improved more than usual in a low humidity environment, the chargeability of the toner is also improved, so that the developing sleeve 9 is used.
There is a tendency for more highly charged toner to accumulate on the sleeve without leaving 2. Therefore, the amount of toner attracted to the developing sleeve 92 increases, and even the regulating blade 94 cannot regulate the amount of toner adhered to the sleeve 92, and an abnormal amount of toner is conveyed to the photoconductor drum PC side to cause non-image portion. Also develops with toner (so-called abnormal toner adhesion).

Further, the toner accumulated on the developing sleeve 92 is repeatedly stressed by the regulating blade 94, so that the toner is rubbed and adhered on the sleeve, so-called toner filming occurs, which leads to image quality. Cause deterioration. Further, due to the stress, the toner is easily deteriorated (smaller particle diameter of the toner, falling off of the fluidizing agent silica, etc.) and the black solid followability is deteriorated.

Further, when the amount of toner accumulated on the sleeve 92 increases, the toner newly supplied to the sleeve 92 is charged not only by the original charging by the regulating blade 94 but also by the friction between the toners. The charged toner having the opposite polarity to the charging polarity increases, which leads to deterioration of image quality. Further, in order to prevent the phenomena such as abnormal toner adhesion, toner filming, and toner deterioration as described above, the charge due to friction is reduced in order to prevent the adjustment and charge-up of the charge amount of the toner. As described above, a measure such as narrowing the width of the surface where the toner regulating blade 94 and the sleeve 92 contact each other can be considered. By doing so, the charge amount of the toner can be reduced, the micro electric field formed between the toner and the sleeve 92 can be weakened, and the toner can be easily separated from the sleeve 92.

However, if the charge of the toner is lowered in the stage before the electrostatic latent image is developed in this way, the fluidity may be reduced due to the dropping of the fluidizing agent silica after a number of times of repeated image formation. Of the toner whose chargeability has deteriorated due to a decrease in the chargeability and toner whose chargeability has deteriorated in a high humidity environment is black that is not subjected to repeated rubbing by the restriction blade 94 because the charging ability of the restriction blade 94 is decreased. After solid development, the toner charge amount is insufficient,
Problems such as background fog and scattering around letters will occur.

Therefore, according to the present invention, a developing member is supplied in a developer supply region to a developer carrying member whose surface moves, and a regulating member for contacting the supplied toner with the surface of the developer carrying member and the developer carrying member. By passing it between the surface and the surface, it is held as a thin layer of charged toner on the surface and conveyed to the developing area for development, and the excess toner is again held on the surface of the developer carrier to the developer supply side. In the one-component developing device for returning, the excess toner held on the developer carrier and subjected to the development is easily separated from the carrier even after a number of times of repeated image formation, whereby the toner to the developing area is formed. Maintains an appropriate amount of conveyance and the charge of the toner, suppresses problems such as toner accumulation on the developer carrier, toner deterioration, and toner filming, and is good without fog or scattering. It is an object to be obtained images.

[0011]

In order to solve the above problems, the present invention firstly provides a one-component developing device having the following features. That is, a part of the surface of the developer carrying member located in the region from the downstream side of the developing region to the toner regulating member in the surface moving direction of the developer carrying member and in a direction transverse to the moving direction of the developer carrying member. Or a member that contacts all of the members, and the surface of the member that contacts the developer carrying member is formed of a material that is biased to the same polarity side as the regular charging polarity of the toner in the charging series relative to the toner. Further, the one-component developing device (first developing device) is characterized in that a material having good conductivity is dispersed in the material.

The member which comes into contact with the surface of the developer carrying member on the downstream side of the developing area may also serve as the seal member shown in FIG. 9 or may be provided separately therefrom. As a material that is biased to the same polarity side as the regular charging polarity of the toner in the charging series than the toner, a fluorine-based resin such as tetrafluoroethylene resin can be exemplified for the negative charging toner. Examples of the positively chargeable toner include polyamide (nylon) and silicone resin. Examples of the material having good conductivity which is dispersed in these materials include carbon, various conductive metal particles, and the like, as well as a suitable charge control substance. It should be noted that this “dispersion” is a concept including applying a charge control substance or the like.

In order to solve the above problems, the present invention provides a one-component developing device having the following features. That is, the toner regulating member is formed of a conductive material, and a means for applying a voltage (V _BLD ) to the regulating member is provided, and further, the toner regulating member is provided on the downstream side of the developing region in the surface moving direction of the developer carrying member. And a means for applying a voltage to the member, which is located in the region from the toner regulating member to abut on a part or all of the surface of the developer carrier in a direction transverse to the surface moving direction of the developer carrier. A surface of the member that comes into contact with the developer carrying member is formed of a conductive material, and the voltage applying unit applies to the member a voltage (V _BLD ) applied to the toner regulating member,
When the toner is a negative charging toner, the condition of V _D > V _BLD is satisfied, and when the toner is a positive charging toner, V _D <V
_The one-component developing device (second developing device) is characterized in that a voltage (V _D ) that satisfies the _BLD condition is applied.

[0014]

According to the first developing device of the present invention, among the toners which are held on the surface of the developer carrying member and are used for development in the developing area, the unconsumed toner is consumed in the downstream side of the developing area. It returns to the toner supply side while passing between the member acting as a charge removing member in contact with the surface of the carrier and in contact with the member.

Then, when the toner passes through the member, it is neutralized or reversely charged by friction with the member, and when it approaches the toner regulating member again, it is easily separated from the surface of the developer carrying member to the toner supply side. Further, since a material having good conductivity is dispersed in the member, the electric charge generated in the member due to friction between the member and the toner that comes into contact therewith is
It escapes through the material having good conductivity and prevents the accumulation of electric charge in the member. Therefore, even if the image formation is repeated many times and the toner on the developer carrying member comes into contact with the member many times, the toner is discharged or reversely charged each time.

When the material with good conductivity to be dispersed is hard, the wear of the charge eliminating member is suppressed to that extent. Further, according to the second developing device according to the present invention, the toner is a toner regulating member and the developing bias potential V _B and the toner regulation in addition given a charge by frictional electrification by passing between the developer carrying member Charge is injected into the toner from the regulating member according to the potential difference of the voltage V _BLD applied to the member, and the charge amount of the toner is adjusted.

At this time, the potential difference between the regulating member and the developer carrying member
As a relational expression representing the toner charge amount when not considering
Electric field E on a flat surface in contact with toner_KAs follows
The model formula is well known. E_K= (1 / 2πε_O) × (q_t/ Γ²) + (Nq_t/
2ε_O) Q_t: Charge amount per toner, γ: toner particle size, n: number of toners per unit area, ε_O: Dielectric constant This formula is used for the external electric field (potential difference between the regulating member and the developer carrier)
If we take the equation into consideration, E_K= (1 / 2πε_O) × (q_t/ Γ²) + (Nq_t/
2ε_O) + K (V_B-V_BLD) K: It is considered to be a proportional constant, and the first two terms on the right side are the positions of the regulating members.
The electric field due to the toner layer in_TBAside
When rearranging, E_TB= E_K-K (V_B-V_BLD), And the contact electric field E_KIs constant, so when passing through the control member
Is V for negatively charged toner._BLDIs V_BLess than
The smaller the value, the more positively charged toner is V. _BLDBut
V_BThe larger the value, the more the electric field due to the toner layer.
E_TBThe absolute value of becomes larger and the amount of toner charge also increases.
It

At the time of development, if the charge amount is appropriately large, a good image free from fogging and scattering can be obtained. However, when the highly charged toner layer is not consumed in the developing region and returns to the supplying portion again. Since the problems such as the abnormal adhesion of toner as described above occur, it is necessary to remove the charge from the toner layer that has passed through the developing area. Therefore, if a static elimination member having at least a surface in contact with the developer carrying member made of a conductive material is installed in a range from the developing region to the toner regulating member and a voltage V _D is applied to the static elimination member, Since it is considered that the model equation described above holds between the charge eliminating member and the toner layer, the electric field due to the toner layer at the position of the charge eliminating member is E _TD , and E _TD = E _K −k (V _B −V _D ) Since the electric field difference due to the toner layer before and after passing through the member is E _TB −E _TD = k (V _BLD −V _D ), when using a negative charging toner, V _D > V _{BLD When} using a positive charging toner When V _D <V _BLD , the charge amount corresponding to the difference between V _D and V _BLD is deprived of the toner layer after development to eliminate the charge. When the charge-removed toner layer returns to the toner supply side, it becomes easy to separate from the sleeve surface, preventing abnormal toner adhesion and the like.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a one-component developing apparatus which is an embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view of the developing apparatus of FIG. FIG. 3 is a schematic sectional view of a one-component developing device according to another embodiment of the present invention, and FIG. 4 is a schematic sectional view of a one-component developing device according to still another embodiment of the present invention.

These developing devices have substantially the same structure and operation as those of the conventional developing device shown in FIG. 9 except that they are provided with a discharging member which will be described later. In each of the developing device shown in FIGS. 1 and 2, the developing device shown in FIG. 3 and the developing device shown in FIG. 4, 1 is a driving roller, 2 is a flexible developing sleeve fitted on the roller, and 3 is A pressing guide for pressing the sleeve against the drive roller 1, 4 a toner regulating blade in contact with the developing sleeve 2, 5 a buffer chamber, 6 a toner supply chamber,
Reference numeral 7 is a toner supply rotating member arranged in the buffer chamber 5, 8 is a toner stirring / supply rotating member arranged in the toner supply chamber 6, and T is a toner used. Drive roller 1 and member 7
Is rotated in the CCW direction in the figure, and the member 8 is rotated in the CW direction in the figure by a drive motor (not shown). In the developing sleeve 2, the slack portion 20 formed on the opposite side by the pressing of the pressing guide 3 is in soft contact with the surface of the photosensitive drum PC of the copying machine in this example.

Further, in each of the developing device shown in FIGS. 1 and 2 and the developing device shown in FIG. 3, 9 is a lower seal member made of a flexible material having elasticity such as maltoprene, and the buffer chamber 5 The toner T is prevented from leaking to the outside. In the developing device shown in FIG. 1 and FIG. 2, a charge removing member 19 is provided so as to contact the developing sleeve 2 at a position between the developing area where the developing sleeve 2 faces the photosensitive drum PC and the lower seal member 9. There is. In the developing device shown in FIG. 3, a charge removing member 29 is provided at a position between the lower seal member 9 and the toner regulating blade 4 so as to come into contact with the developing sleeve 2. In the developing device shown in FIG. 4, instead of the lower seal member 9, a charge eliminating member 39 that also functions as the seal member faces the developing sleeve 2. The charge removing members 19, 29, 39 are all developing device casings C.
Supported by.

The charge removing member 19 covers the toner layer 2 over the entire direction crossing the surface moving direction CCW of the developing sleeve 2.
It abuts via t (see FIG. 2). Static eliminator 29, 39
Also, as in the case of the charge removing member 19, it contacts the surface of the developing sleeve 2. As described above, in any of the developing devices, the charge removing member is installed at a portion from the downstream side of the developing area to the toner regulating blade 4 in the rotating direction of the developing sleeve 2. As in the developing device of FIG. 4, if the static eliminating member 39 that also serves as the lower seal member is adopted,
The contact pressure with respect to the developing sleeve 2 is set in a certain range because it also serves as a seal member, but it is not necessary to provide a charge eliminating member separately from the seal member, which is advantageous in manufacturing device cost.

Each of the charge removing members 19, 29 and 39 is made of a material which is biased in the charging series with respect to the toner T and on the same polarity side as the normal charging polarity of the toner, and is made of a material having good conductivity. It is dispersed. Then, as represented by the static elimination member 19 in FIG. 2, the static elimination bias power source 191 is connected to any of the static elimination members, and the static elimination bias potential V _D is applied.

The static elimination bias potential V _D is the photosensitive drum P.
After the development of the electrostatic latent image on C, the power supply 21 is applied to the developing sleeve 2 so that the charge can be smoothly transferred from the surplus toner layer remaining unconsumed on the developing sleeve 2 to the charge removing member. With respect to the surface potential of the toner layer obtained by adding the potential V _T of the toner layer 2t generated by charging the toner to the developing bias V _B , the bias potential V _D > the toner layer surface potential (when the negatively chargeable toner is used). V _B + V _T ) (<development bias), and when using a positively chargeable toner, a static elimination bias potential V _D <toner layer surface potential (V _B + V _T ).
(> Development bias). Note that this inequality considers the positive and negative of each potential.

In the example described above, the static elimination bias power source 19
Although 1 is a DC power supply, it is conceivable to employ an AC power supply capable of applying an alternating voltage under appropriate conditions instead of this. As shown in FIG. 5, in the developing sleeve 2, as in the conventional one-component developing device, the central portion 2a is used for toner conveyance, and the toner layer 2t is held there, but both ends 2b are provided. The toner layer is not formed in order to prevent toner leakage from both ends. Therefore, in FIG.
As representatively shown in FIG. 2, the charge removing member is brought into contact with the central portion 2a through the toner layer 2t and directly brought into contact with both ends 2b thereof, so that the development within the range satisfying the voltage condition is performed. The bias potential V _B is also applied to the charge eliminating member at the same time so that the potential of the charge eliminating member becomes the same potential as the developing sleeve applied voltage, and a contact for applying a voltage to the charge eliminating member is not necessary, or between the charge eliminating member and the developing sleeve 2. May be eliminated, or an insulating member for preventing leakage may be unnecessary, which may be advantageous in terms of cost. This also applies to the charge removing members 29 and 39.

According to each of the developing devices described above, the residual toner T remaining on the surface of the developing sleeve 2 and used for development in the developing region is the charge removing member 19 in contact with the sleeve 2. (Or 29 or 39) while returning to the buffer chamber 5 through the space between the member and the sleeve 2. When passing through the charge removing member, the charge is removed or reversely charged due to friction with the member, and when returning to the buffer chamber 5, the developing sleeve 2 is easily separated from the surface.

Further, since a material having good conductivity is dispersed in the charge eliminating member, the toner T and the toner T passing through in contact therewith are dispersed.
Electric charges generated in the charge eliminating member due to friction with are released through the material having good conductivity, and accumulation of charge in the charge eliminating member is prevented. Therefore, no matter how many times the toner on the developing sleeve 2 comes into contact with the charge removing member by repeating image formation a number of times, the toner is charged or reversely charged each time.

In the developing device described above, the charge removing member 19
(Or 29 or 39) contacts the entire toner layer in the longitudinal direction of the developing sleeve 2, but it is also conceivable that only the toner layers on both ends of the developing sleeve 2 are contacted with the charge eliminating member. Because the pressing force of the toner regulating blade 4 is originally lower at both end portions of the developing sleeve 2 than that against the central portion of the sleeve, and the force for regulating the toner adhesion amount to the sleeve 2 is weak. This is because abnormal adhesion or toner filming is likely to occur, and even when no problem occurs in the sleeve central portion, toner abnormal adhesion or filming may occur only in the end portion.

FIGS. 6 and 7 show an example in which the charge removing members 119 and 139 are provided for the toner layer on the end portion of the developing sleeve 2 as described above. The materials and the conductivity of these static eliminating members are the same as those of the static eliminating members 19, 29, 39. In the developing device of FIG. 6, the charge removing member 119 is provided at a position between the developing area and the lower seal member 9.
In the developing device, the charge removing member 139 also serves as a part of the lower seal member 9.

Next, Experimental Examples 1 and 2 in which the used toner T, a charge removing member and the like are used under the following conditions, and Comparative Examples 1 and 2 for them will be described. [Experimental Example 1] Toner T: Next negatively chargeable toner 100 parts by weight of thermoplastic polyester resin, 3 parts by weight of additive for preventing offset (low molecular weight polypropylene), carbon black MA # 100 (manufactured by Mitsubishi Kasei) 10 parts by weight Part, 3 parts by weight of Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.) were placed in a 10-liter Hensyl mixer, and 200 r
After mixing for 2 minutes at pm, PCM30 (liter / d:
22.5m after continuous extrusion and kneading at 32.5) and cooling
Coarsely pulverized with an m-mesh feather mill, further finely pulverized with a jet pulverizer, and then cut into coarse and fine powders with an airflow classifier to obtain particles having an average particle diameter of 11 μm. A toner obtained by treating the surface with 0.2 wt% of hydrophobic silica (R-974: manufactured by Nippon Aerosil Co., Ltd.).

Static elimination member: A tape (No. 903SC, manufactured by Nitto Denko Corporation) in which carbon powder is dispersed in tetrafluoroethylene resin (Teflon). As shown in FIG. 4, it also serves as a lower sealing member, and as shown in FIG. 5, both ends of the developing sleeve 2 are brought into electrical contact with the sleeve. Developing sleeve 2: Nickel toner control blade 4: Stainless steel Toner supply rotary member 7: Aluminum Photoconductor drum PC used: Negatively charging photoconductor drum [Comparative example 1] Static eliminator: Tetrafluoride ethylene resin (Teflon) It consisted of a tape consisting of only.

As shown in FIG. 4, it also serves as a lower seal member, but is electrically insulated from the developing sleeve 2. Others are the same as in Experimental Example 1. Evaluation Non-image area Sleeve Black solid followability Toner development Filming Experimental example 1 ○ ○ ○ Comparative example 1 ○ ○ × [Experimental example 2] Toner T: Next positively chargeable toner 100 parts by weight of thermoplastic styrene acrylic resin, offset 3 parts by weight of a preventive additive (low molecular weight polypropylene), carbon black MA # 100 (manufactured by Mitsubishi Kasei) 1
A toner obtained by using 0 part by weight and 3 parts by weight of Bontron N-01 (manufactured by Orient Chemical Industry Co., Ltd.) in the same manner as the negatively chargeable toner.

Static elimination member: Nylon with carbon powder 22
It was formed of a sheet in which wt% was dispersed. As shown in FIG. 4, the lower seal member was also made to double, and as shown in FIG. 5, both ends of the developing sleeve 2 were brought into electrical contact with the sleeve. Photosensitive drum PC used: Positively charged photosensitive drum Others are the same as in Experimental Example 1. [Comparative Example 2] Static elimination member: formed of a sheet made of nylon only.

As shown in FIG. 4, it also serves as a lower seal member, but is electrically insulated from the developing sleeve 2. Others are the same as in Experimental Example 2. Evaluation Non-image area Sleeve Black solid followability Toner development Filming Experimental example 2 ○ △ ○ Comparative example 2 ○ △ △ In each of the above evaluations, "○" indicates a good state in which there is no toner development in the non-image area, and the developing sleeve. 2 shows a good state in which toner filming does not occur and a black solid-following property are good. “Δ” indicates a slightly defective state, and “x” indicates a defective state. .

The evaluation was conducted by visually observing the copy paper image and the surface of the developing sleeve 2 after the copying machine using the developing device under such conditions was continuously operated for 10 hours. Regarding the black solid followability, the image densities of the front end and the rear end of the copied image were measured with a reflection densitometer, and if the density difference was 0.2 or less, it was judged as good. As can be seen from the mutual evaluation of Experimental Example 1 and Comparative Example 1 and the mutual evaluation of Experimental Example 2 and Comparative Example 2 described above, Experimental Example 1 and Experimental Example 2 using the static elimination member in which a material having good conductivity is dispersed. Then, the comparative example 1 and the comparative example 2 which used the static elimination member which did not disperse such a conductive material.
It can be seen that a good result is obtained as a whole as compared with.

As described above, according to Experimental Examples 1 and 2 according to the present invention, since carbon powder having good conductivity is dispersed in the charge removing member, the excess toner remains on the developing sleeve 2 even after a number of repeated image formations. Since the toner is easily separated, the amount of toner conveyed to the developing area and the charging of the toner can be maintained at an appropriate level, and the developing sleeve 2
It is possible to suppress the occurrence of the above-mentioned problems such as filming of the toner and deterioration of the toner (which leads to defective black solid tracking), and a good image can be obtained as a whole.

In the above-mentioned experimental example, a material such as Teflon or nylon, which is biased to the same polarity side as the regular charging polarity of the toner, is used as the material of the static elimination member, but the static elimination member is not limited to this. Alternatively, the charge control substance may be dispersed or thinly applied to a resin or a metal member to form a material that is biased to the same polarity side as the regular charge polarity of the toner.

Examples of such a charge control substance include electron donor dyes (for example, nigrosine dyes, phthalocyanine dyes), alkoxylated amines, quaternary ammonium salts (activators), and alkylamidolines for plus type toners. , Tungsten, tungsten compounds, molybdic acid chelate pigments, fluorine-based activators, hydrophobic silica, etc. can be used. In addition, electron-accepting dyes (monoazo dye metal complex salts) and electron-accepting dyes can be used for negative toners. Organic complexes, chlorinated polyolefins, chlorinated polyesters, polyesters having an excess of acid groups, copper phthalocyanine sulfonylamines, oil blacks, naphthenic acid metal salts, fatty acid metal salts, resin acid soaps and the like can be used.

Next, still another embodiment of the present invention will be described with reference to FIG. The one-component developing device shown in FIG. 8 has substantially the same configuration as the developing device shown in FIGS. 1 and 2. The same parts as those of the apparatus shown in FIGS. 1 and 2 are designated by the same reference numerals. The difference from the device shown in FIGS. 1 and 2 is that
The bias power source 41 is connected to the toner regulating blade 4 so that the bias potential V _BLD can be applied. Also in this apparatus, the developing bias power source 21 is connected to the developing sleeve 2 so that the developing bias potential V _B is applied, and the bias power source 191 is connected to the discharging member 19 to remove the discharging bias potential. V _D
Is applied.

A bias potential V is applied to the toner regulating blade 4.
_{The BLD} is applied to increase the charge amount of the toner held on the developing sleeve 2 and adjust the charge amount. When using a negatively chargeable toner, V _D > V _BLD , When using positively charged toner, V _D <V _BLD
The bias potentials V _D and V _BLD are determined so that Note that this inequality considers the positive and negative of each potential.

As described above, by applying the bias potential to the toner regulating blade 4 and the charge removing member 19, the toner layer provided for development maintains the charge amount required for the development, and the toner layer after the development is removed. _Deprives the charge amount according to the difference between V _D and V _BLD to eliminate the charge, and thus returns to the buffer chamber 5 after being developed and held on the developing sleeve 2, and when the toner layer returns to the buffer chamber 5, the sleeve 2 surface It is easy to remove the toner from the toner, and the problems such as the abnormal toner adhesion can be solved.

In the developing device shown in FIGS. 3 and 4, as in the device shown in FIG. 8, the bias power source 41 is connected to the toner regulating blade 4 to apply the bias potential V _BLD , and the charge removing member 19 and A static elimination bias potential V _D is applied to 39, and the condition of V _D > V _BLD is satisfied when the negative charging toner is used, and the condition of V _D <V _BLD is satisfied when the positive charging toner is used. As a result, the same effect as the device of FIG. 8 can be obtained.

As shown in FIG. 5 as a representative of the static elimination member 19, the static elimination member is also brought into direct contact with both ends 2b of the developing sleeve 2 where there is no toner layer, so that the static elimination member is connected to the developing sleeve 2. At the same potential V _B , the condition of V _B (= V _D )> V _BLD is used when the negative charging toner is used, and the condition of V _B (= V _D ) <V _BLD is used when the positive charging toner is used. The same effect can be obtained even if the above is satisfied.

When V _D = V _B is set as described above, a contact for applying a voltage to the charge eliminating member becomes unnecessary, conduction between the charge eliminating member and the developing sleeve 2 is eliminated, and an insulating member for preventing leakage is provided. Since it is unnecessary, the cost will be reduced accordingly. Further, even in the case where the bias potential is applied to the toner regulating blade 4 as described above, even if the charge removing member is brought into contact with only the toner layers on both ends of the developing sleeve 2 as in the developing device shown in FIGS. 6 and 7. Good.

Under the conditions of Experimental Example 1 and Experimental Example 2 described above in which the bias potential was not applied to the toner regulating blade 4, a power source 41 was further connected to the blade 4 as shown in FIG. _{Apply BLD} ,
The potential condition _{V B (= V D)>} V BLD for Experimental Example 1 (negatively chargeable toner used), Experimental Example 2 for (positively chargeable toner used) the potential condition V _B (= V _D) < V
_{When BLD} is adopted and a copying operation is performed, problems such as abnormal adhesion of toner on the developing sleeve 2, filming, and deterioration of toner are suppressed, and a good image without toner fog or toner scattering as a whole is obtained. was gotten.

[0046]

According to the present invention, the developing member is supplied in the developer supplying area to the developer carrying member whose surface moves, and the supplied toner is brought into contact with the surface of the developer carrying member, and the developer. By passing between the surface of the carrier and the surface of the carrier, it is held as a thin layer of charged toner and conveyed to the developing area.
A one-component developing device that is used for development and returns the excess toner to the developer supply side while holding the excess toner on the surface of the developer carrier, and the excess toner after being retained by the developer carrier and provided for the development. Is easily separated from the carrier even after a number of times of repeated image formation, thereby maintaining an appropriate amount of toner conveyed to the developing area and the charging of the toner,
It is possible to provide a toner capable of suppressing the occurrence of problems such as toner accumulation on the developer carrying member, toner deterioration, and toner filming, and obtaining a good image without fogging or scattering.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a developing device according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of the developing device in FIG.

FIG. 3 is a schematic sectional view of a developing device according to another embodiment of the present invention.

FIG. 4 is a schematic sectional view of a developing device according to still another embodiment of the present invention.

FIG. 5 is a perspective view of a developing device according to still another embodiment of the present invention.

FIG. 6 is a perspective view of a developing device according to still another embodiment of the present invention.

FIG. 7 is an exploded perspective view of a developing device according to still another embodiment of the present invention.

FIG. 8 is a schematic sectional view of a developing device according to still another embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of a conventional example.

[Explanation of symbols]

1 Driving Roller 2 Developing Sleeve 3 Pressing Guide 4 Toner Regulation Blade 5 Buffer Chamber 6 Toner Supply Chamber 7 Toner Supply Rotating Member 8 Toner Agitating / Supply Rotating Member 9 Sealing Member T Toner PC Photosensitive Drum 19, 29, 39 Electrifying Member 21 Development Bias power supply V _B Development bias potential 191 Static elimination bias power source V _D Static elimination bias potential 41 Blade voltage application power source V _BLD Blade application voltage V _T Toner layer potential

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masami Eda Inventor Masami Edo 2-3-13 Azuchi-cho, Chuo-ku, Osaka, Osaka International Building Minolta Camera Co., Ltd. (72) Shinichi Takemoto 2-chome Azuchi-cho, Chuo-ku, Osaka No. 13 in Osaka Kokusai Building Minolta Camera Co., Ltd. (72) Inventor Tamotsu Sakuraba 2-33 Azuchicho, Chuo-ku, Osaka City Osaka Kokusai Building Minolta Camera Co., Ltd.

Claims (2)

[Claims] 1. A regulating member for supplying a developing toner to a developer carrier whose surface moves, in a developer supplying region, and abutting the supplied toner on the surface of the developer carrier and the surface of the developer carrier. One component which is held as a thin layer of charged toner on the surface by passing it between the two and is conveyed to the developing area for development, and is returned to the developer supply side while holding the excess toner on the surface of the developer carrier. In the developing device, in the surface moving direction of the developer carrying body, the carrier surface is located in the area from the downstream side of the developing area to the toner regulating member and crosses the developer carrying body surface moving direction. A part of or all of the member is in contact, and the surface of the member in contact with the developer carrying member is formed of a material that is offset to the same polarity side as the regular charging polarity of the toner in the charging series relative to the toner. Yes Further, a one-component developing device characterized in that a material having good conductivity is dispersed in the material. 2. A developer carrier is provided on a developer carrier whose surface moves.
The developing toner is supplied in the supply area, and the supplied toner is
The voltage (V_BLD) Is applied
Toner regulating member made of a conductive material
And the surface of the developer-carrying member.
Hold it as a thin layer of charged toner on the surface and transport it to the development area,
It is used for development and excess toner is retained on the surface of the developer carrier.
A one-component developing device that returns to the developer supply side while holding it
In the surface moving direction of the developer carrier, the development
Located within the area from the downstream side of the area to the toner regulating member.
The developer carrier in a direction transverse to the surface moving direction.
A member that abuts all or part of the surface of the carrier
And a means for applying a voltage to the member,
The surface of the material that comes into contact with the developer carrier has conductivity
The voltage applying means is formed of a material,
The voltage (V _BLD) To
If the toner is a negatively chargeable toner, V_D> V_BLD
If the toner is a positively chargeable toner,_D<
V_BLDVoltage (V_D) To apply
A one-component developing device characterized in that