JPH11242375A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device which does not cause developing history by generating plural electric fields including the electric field for moving toner from a toner carrier to a toner supply member till starting the image formation of a next page after finishing image formation. SOLUTION: A power source means 31 is provided with a developing power source 32 impressing developing bias on the toner carrier 16 and a supply power source 33 impressing the bias on the toner supply member 15. Then, the means 31 is connected to a CPU 35 through a switch 34 and controlled by the CPU 35. The power source 33 generates the electric field for moving the toner from the member 15 to the carrier 16 and the electric field for moving the toner from the carrier 16 to the member 15. Since a toner peeling effect is kept till starting the image formation of the next page, the excess electrification of the toner is prevented, and the developing history caused by the excess electrification of the toner is prevented, and further the toner is prevented from being stuck to the carrier 16 and a toner regulating means 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of an image forming apparatus using an electrophotographic method, such as a copying machine, a printer, a facsimile, etc., and in particular, an image forming apparatus characterized by a power source of a developing device. is there.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus for forming an image using a toner forms an electrostatic latent image on a latent image carrier using a photoconductive substance based on a so-called Carlson process, and then forms an image. Fine powder called "toner" is selectively adhered to the latent image, developed, and the latent image is visualized.
The developed toner is transferred to a transfer material such as paper as necessary, and then fixed by heat and pressure or solvent vapor to obtain an image-formed product.

In a developing device used in the image forming apparatus, a toner supply member made of a conductive foam or the like is arranged so as to rotate in contact with a toner carrier made of a conductive rubber or the like. In general, the toner is adhered to the surface of the toner carrier by the mechanical conveyance force and the electrostatic force due to the triboelectric charging by the contact rotation and is uniformly conveyed.

However, in the configuration of the conventional developing device, the toner on the toner carrier is consumed only at a portion corresponding to the latent image, and the toner layer on the toner carrier in the next process is not included in the previous process. The newly supplied toner and the toner that has not been consumed remain in the places where the toner has been consumed, but these toners have different charge amounts. More specifically, the amount of toner remaining unconsumed becomes excessively high compared to newly supplied toner, because the amount of contact with the toner regulating means and the toner supply member is increased due to frictional charging.
Therefore, when printing the next page, there has been a problem that shading unevenness such as a negative afterimage corresponding to the latent image of the previous page occurs (hereinafter, this phenomenon is referred to as a development history). Further, there has been a problem that the excessively charged toner increases the adhesive force to the toner carrier and the toner regulating means due to the electrostatic force, so that the toner is easily fixed.

Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 56433 (known example 1) proposes applying a predetermined voltage between a toner carrier and a toner supply member. That is, at the time of image formation in which toner is supplied to the electrostatic latent image on the latent image carrier and development is performed, the potential difference obtained by subtracting the voltage related to the toner carrier from the voltage of the toner supply member is set to the same polarity as the toner polarity. By applying such an electric field, the toner on the toner supply member can be positively transported to the toner carrier, which leads to an improvement in toner transportability.

On the other hand, at the end of image formation, that is, at the end of development of the electrostatic latent image, an electric field is applied to the negative polarity side of the toner polarity to move the toner from the toner carrier toward the toner supply member. By generating an electric field and peeling off the residual toner that has not been developed into the electrostatic latent image, the toner is prevented from sticking to the toner carrier or the toner regulating means due to the residual toner and the development history due to excessive charging of the residual toner is prevented.

Japanese Patent Application Laid-Open No. 60-114,891 (known example 2) proposes a device for exfoliating toner adhered to a toner carrier.

That is, by providing the scraping means in the supply means, the residual toner on the toner supply member is constantly scraped and the effect of removing the residual toner is maintained.

[0009]

In the above-mentioned known examples 1 and 2, there are still some points to be improved.

That is, in the case of the known example 1, during the period other than the time of image formation (the time from the end of the previous image formation to the start of the next image formation, which is called the so-called paper interval), the toner carrying Since the electric field for moving the toner from the body toward the toner supply member continues to be generated, the residual toner in the non-image portion can be once peeled off, but thereafter, the mechanical rotation caused by the rotation of the contact between the toner supply member and the toner carrier is performed. The toner that has re-adhered to the surface of the toner carrier due to the conveying force cannot be easily removed again because the surface of the toner supply member has been filled with residual toner in the previous process. Therefore, the toner newly adhering to the surface of the toner carrier is not consumed by the image carrier until printing of the next page is started. There was a risk.

This overcharged toner is used at the leading edge of an image on the next page. Normally, the charge amount is different from that of the toner, so that a density difference occurs during development, causing a new development history,
Alternatively, there is a concern that the excessively charged toner may cause a problem that the toner adheres to the toner carrier and the toner regulating means due to the electrostatic force.

Further, even in the case of the second prior art, since a toner scraping means must be additionally provided on the toner supply member, there is a problem that the apparatus becomes complicated and the cost is increased.

The present invention solves the above-mentioned problems, and a first problem to be solved by the present invention is to provide a device which does not generate a development history.

A second problem to be solved by the present invention is to provide a toner which can safely prevent the toner from sticking to the toner carrier and the toner regulating means.

A third problem to be solved by the present invention is to provide a small-sized and low-cost configuration.

[0016]

Means for solving the problems The means for solving the above-mentioned problems according to the present invention are as follows.

(1) Developing means comprising an image carrier, a toner carrier and a toner supply member, for forming an image on the image carrier with toner, and an image for transferring a toner image on the image carrier to a transfer medium A power supply unit for generating an electric field between the toner carrier and the toner supply member, wherein the power supply unit includes at least the toner from the end of image formation to the start of image formation of the next page. An image forming apparatus capable of generating a plurality of electric fields including an electric field for moving toner from a carrier toward the toner supply member.

(2) The power supply generates an electric field for moving the toner from the toner carrier toward the toner supply member for at least one rotation of the toner carrier before the start of image formation of the next page. The image forming apparatus according to the above (1), wherein the image forming apparatus is configured to perform the following.

(3) An electric field for moving the toner from the toner carrier toward the toner supply member by the power supply means,
The image forming apparatus according to the above (1) or (2), characterized in that the image forming apparatus is configured to end at the time of starting image formation of the next page.

(4) The power supply means generates an electric field for moving the toner from the toner carrier toward the toner supply member before image formation, and terminates the image formation at the end of image formation. The image forming apparatus according to (1) or (2), wherein

(5) The image forming apparatus according to (4), wherein the power supply means generates an electric field that allows toner to move from the toner supply member toward the toner carrier after image formation is completed. Image forming apparatus.

(6) The power supply means generates an electric field that allows the toner to move from the toner supply member toward the toner carrier.
(5) The image forming apparatus according to (5), wherein the image is generated at least for one rotation of the toner carrier.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) 1. Corresponding Means FIG. 1 schematically shows a main part of an image forming apparatus 100 according to the present invention.
0, and a power supply control unit 30 is provided.

Although not shown, an exposure unit and a transfer unit for scanning the surface of the latent image carrier 20 with a laser beam or the like are arranged.

The developing device 10 is provided with a rotatable toner stirring means 12 in a toner hopper 11, and a developing chamber 14 communicating with the toner hopper 11 through a transparent window 13 is pressed against the surface thereof. And a toner supply member 15 and a toner carrier 16 which are arranged adjacent to each other and driven to rotate in the directions of arrows A and B, respectively.
The tip end of the toner regulating unit 17 formed of a plate material such as stainless steel or copper is formed in an R shape.
The portion 17 </ b> A is disposed so as to uniformly contact the surface of the toner carrier 16.

Next, the power supply control section 30 is provided with a power supply means 31.
A developing power supply 32 for applying a developing bias to the toner supply member 15 and a supply power supply 33 for applying a bias to the toner supply member 15 are connected to and controlled by a CPU 35 via a switch 34. An electric field that can move from the toner supply member 15 to the toner carrier 16;
An electric field for moving from the toner carrier 16 to the toner supply member 15 can be generated.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a material for the toner supply member 15, it is preferable to select an elastic body in order to stabilize the contact with the toner carrier 16. Therefore, polyurethane foam, polystyrene foam, polyethylene foam, polyester foam, Ethylene propylene foam, nylon foam, silicone foam and the like can be used. In this example, polyurethane foam was used.

The foam cell of the toner supply member 15 can be either a single cell or open cell. If the foam cell is a continuous cell, the toner enters the inside of the foam cell of the toner supply member 15 and becomes Since it is predicted that toner aggregation will occur, toner transportability will be reduced, and furthermore, it is expected that this will lead to an increase in the torque of the entire apparatus, a single-cell foam is preferable.

A hardness of 10 ° to 40 ° (measured by an Asker C hardness meter) can be used, but a hardness of 35 ° to 40 ° which has a large scraping effect of residual toner is optimal.
° is more preferable. Moreover, the resistance value is 10 ³ ~
Those having a resistivity of 10 ⁷ Ωcm (volume resistance value) were used.

Although a foam material is used in this embodiment, a rubber material having elasticity may of course be used, for example, silicone rubber, urethane rubber, natural rubber, isobrene rubber, styrene butadiene. Rubber, butadiene rubber, chlorobrene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, acrylic rubber, etc. can be used, and conductive materials such as carbon are dispersed and molded into foam materials or rubber materials. Can be used.

Next, the toner carrier 16 is made of a base material obtained by dispersing and molding carbon as a conductive agent in polyurethane rubber. The base material is made of polyurethane rubber. It is desirable that the base material take into account the triboelectric charge polarity with the toner.

In this embodiment, since the negative polarity toner is used, it is needless to say that the triboelectric charge polarity of the base material of the toner carrier 16 needs to be more positive than that of the toner. For example, in addition to polyurethane rubber, natural rubber, isobrene rubber, styrene butadiene rubber, butadiene rubber, chlorobrene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, acrylic rubber, and the like can be used.

Although the toner carrier 16 of this embodiment uses a single-layer rubber, it can be used even if it is coated on the upper layer of the single-layer rubber. As the coating material, polyethylene, polystyrene, nylon, polyurethane, polyester, acrylic, or the like can be used.

Further, those having a hardness of 20 ° to 50 ° (measured by Asker A hardness meter) can be used.

The resistance value was 10 ³ Ω to 10 ⁸ Ωcm (volume resistance value).

In this embodiment, since the latent image carrier 20 is made of a drum-shaped rigid body, the toner carrier 16 is made elastic. However, the latent image carrier 20 is formed on a surface of a nickel electroformed tube or resin. When an elastic body such as a belt in which a photosensitive layer is formed on a film coated with a conductive layer is used, the toner carrier 16 can be made of a rigid body such as a metal. As a material, aluminum, stainless steel, nickel, titanium, zinc, thallium, Nb, Pt and the like can be used.

The surface roughness of the toner carrier 16 is Rz
The processing method was a polishing method,
Sand blasting, paper method, shot method, steel wool method, brush method, honing method, laser method and the like can be adopted.

As another means of the toner restricting means 17, there can be used one in which an elastic chip such as an R-shaped rubber is formed on a plate material such as stainless steel, copper, iron and resin. Silicone rubber, urethane rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chlorobrene rubber, butyl rubber, ethylene propylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, acrylic rubber, etc. can be used, and carbon etc. Can be used.

[0040] Those obtained by integrally molding these rubber materials alone can be used in the same manner. However, a resin material such as polyethylene, polystyrene, nylon, polyurethane, polyester or the like may be coated on the upper layer of the above materials. .

2. Usage The usage of the image forming apparatus 100 is as follows.

General Procedure The developing device 10 and the latent image carrier 2 are started by starting means (not shown).
When the toner supply unit 12 is started, the toner supply unit 12 is turned to rotate the toner (toner T), which is a non-magnetic-component toner and has a negative characteristic, contained in the toner hopper 11 and passes through the transparent window 13 while being stirred. The toner carrier 16 and the toner supply member 15 are supplied into the developing chamber 14 at a peripheral speed ratio of 1: 0.5 to 1: 0.9, preferably 1: 0.8.
Are rotated in the directions of arrows A and B, respectively, so that the toner T is supplied onto the toner supply member 15 and transferred to the position of the contact portion C with the toner carrier 16.

At the contact portion C, the toner T is charged, is conveyed onto the toner carrier 16, and is uniformly thin-layer-charged by the tip R-shaped portion 17 A of the toner regulating means 17, so that the toner T is brought into contact with the latent image carrier 20. The developer is conveyed to the development nip D between the toner carrier 16 and the toner carrier 16.

On the other hand, on the latent image carrier 20, an arrow E
While rotating in the direction, the surface is uniformly charged by a charging unit (not shown), and an electrostatic latent image portion is formed by a laser beam or the like emitted from the exposure unit. And developed into a visible image.

If the peripheral speed ratio between the toner carrier 16 and the toner supply member 15 is lower than the above, the transportability of the toner T is hindered. Even if the peripheral speed ratio is high, the transportability of the toner T is not necessarily improved. It is feared that the driving torque increases.

By the way, in the time chart shown in FIG.
And the power supply 33. The developing power supply 32 is turned on immediately before the printing of the first page is started by operating the switch 34.
At the end of image formation, the power is turned off.
Applies a bias that allows the toner T to move from the toner supply member 15 to the toner carrier 16 when the developing power supply 32 is ON.

In the case of the first embodiment, the developing power source 32
When the developing bias at the time of ON is -300 (V), the supply bias is the same as the developing bias, so that the toner T can be supplied by the mechanical conveyance force generated by the toner carrier 16 and the toner supply member 15.

After the image formation is completed, the developing power supply 32 is turned off. At this time, the supply power supply 33 generates an electric field (separation bias) for moving the toner T from the toner carrier 16 to the toner supply member 15. I do.

Therefore, when the developing bias was 0 (V) when the developing power supply 32 was turned off, +300 (V) was applied as the supply bias.

As a result, the undeveloped toner T on the toner carrier 16 that has passed through the developing nip D is separated from the surface of the toner supply member 15 by a potential difference from the toner supply member 15.

Thereafter, the entire surface of the toner supply member 15 is covered with the undeveloped toner T from the toner carrier 16. At this time, the toner T is temporarily released from the surface of the toner supply member 15. An electric field (open bias) is generated, the toner T on the toner supply member 15 is removed, and after the surface of the toner supply member 15 is refreshed, a separation bias is applied again to assist the separation to the toner supply member 15. .

In the first embodiment, the power supply 33 is set to the same bias as the developing bias and to the open bias.

FIG. 3 shows the charge amount on the toner carrier 16 in the first embodiment.
It is verified that excessive charging of the toner T on the toner carrier 16 can be effectively prevented because the peeling bias and the opening bias are repeated.

In this embodiment, the release bias at the time of image formation is set to the same bias as the developing bias. However, if a bias that is positively released by the electrostatic force from the toner supply member 15 is applied, Needless to say, it will be more effective.

As described above, since the toner peeling effect can be maintained until the start of image formation of the next page, it is possible to prevent the toner T from being excessively charged, and thereby the development history and the toner T to the toner carrier 16 and the toner regulating means 17. Can be prevented from sticking.

(Embodiment 2) A power supply controller 30a according to the image forming apparatus 100a of the present invention shown in FIGS.
The second embodiment is characterized by the fact that the supply power supply unit 33a moves the toner bias from the toner carrier 16a toward the toner supply member 15a until the start of image formation of the next page. The other points are common to the first embodiment.

That is, as shown in FIG. 4, after the developing power supply 32a is turned off after the completion of the first page, the supply power supply 33a repeatedly generates an opening bias and a peeling bias. At this time, the peeling bias is applied to the toner carrier 16a. Is generated for one or more rounds of time.

FIG. 5 is a diagram showing the relationship between the time of occurrence of the separation bias of the toner supply member 15a and the amount of charge of the toner T on the toner carrier 16a. When the peeling bias is applied for a period corresponding to the circumference, the toner charge amount on the toner carrier 16a can be reduced to almost 1/3. Is verified.

Incidentally, if the toner is continuously generated for a time corresponding to about 5 rotations of the toner carrier 16a, the toner T on the toner carrier 16a
It is recognized that the charge amount has slightly increased,
The reason for this is that the peeling effect has been reduced because the peeled toner has accumulated on the toner supply member 15a. Therefore, taking this time into consideration, switching to the open bias and once removing the toner T on the toner supply member 15a. And
By repeating the process of refreshing the surface of the toner supply member 15a and generating an open bias again, the peeling effect of the toner supply member 15a can be further maintained.

As described above, the generation time of the peeling bias for moving the toner from the toner carrier 16a to the toner supply member 15a by the time the power supply controller 30a starts the image formation of the next page is determined by the toner carrier. If 16a is generated for one or more rounds, preferably three or more rounds, it can be said that the peeling effect can be further improved as compared with the first embodiment.

(Embodiment 3) A power supply control unit 30b according to the image forming apparatus 100b of the present invention shown in FIGS. 6 and 7.
The third embodiment is characterized in that the supply power source 33b generates a peeling bias for moving the toner from the toner carrier 16b toward the toner supply member 15b, and the other points are the first and second embodiments. Common to 2.

That is, as shown in FIG. 6, after the development power supply 32b is turned off after the completion of image formation for the first page, the supply power supply 33b
Is to repeatedly generate an opening bias and a peeling bias, and thereafter, the peeling bias generated immediately before forming the image of the next page is terminated at the start of the image forming of the next page.

FIG. 7 is a graph showing the idling time of the toner carrier 16b and the charge amount of the toner T on the toner carrier 16b. As shown in FIG. 7, the longer the idling time of the toner carrier 16b becomes, Since it is recognized that the toner charge amount on the toner carrier 16b increases, in order to further increase the peeling bias effect of the toner supply member 15b, it is preferable that the peeling bias is continuously generated until immediately before the start of image formation of the next page. Is verified.

(Embodiment 4) A characteristic point of Embodiment 4 of the power supply control unit 30c according to the image forming apparatus 100c of the present invention shown in FIG.
There is a timing at which a separation bias is generated to move the toner from the toner supply member 6c toward the toner supply member 15c, and the other points are common to the first and second embodiments.

That is, as shown in FIG. 8, after the developing power supply 32c is turned off after the end of the first page, the supply power supply 33c repeatedly generates an opening bias and a peeling bias, and the peeling that occurs immediately before the start of image formation of the next page. The bias is generated until the end of image formation.

As described above, if the peeling bias continues to be generated during the image formation, the development history occurring in one page area is also effective, and it corresponds to the area where the image is formed also in one page area. There is a difference between the charge amount on the toner carrier 16c and the charge amount of the toner T corresponding to the non-image area, but in the fourth embodiment, the peeling bias is applied even during image formation. Since the toner is continuously generated between the toner supply member 15c and the toner supply member 15c, the non-image forming portion toner T on the toner carrier 16c can be developed while always being peeled off to the toner supply member 15c. Can maintain in quantity.

Therefore, in the fourth embodiment, the development history can be greatly reduced not only at the leading end of the image but also over the entire image forming area.

(Embodiment 5) A characteristic point of Embodiment 5 of the power supply control unit 30d according to the image forming apparatus 100d of the present invention shown in FIG. 9 is that the supply power supply 33d generates a peeling bias during image formation. After that, an electric field (supply bias) for moving the toner T from the toner supply member 15d toward the toner carrier 16d is generated, and the other points are common to the fourth embodiment.

That is, as shown in FIG. 9, after the development power supply 32d is turned off after the completion of image formation for the first page, the supply power supply 33d is turned off.
Causes a release bias and a peeling bias to be repeatedly generated so that a peeling bias generated immediately before the start of image formation of the next page is generated until the end of image formation. Immediately thereafter, a supply bias is applied between the toner carrier 16d and the toner supply member 15d. Is generated.

As described above, if a peeling bias is continuously generated during image formation, the toner T is always peeled off from the toner carrier 16d.
If the toner supply capability from the printer decreases, the supply performance may decrease. Particularly, in continuous printing, the toner is conveyed by the mechanical conveyance force between the toner carrier 16d and the toner supply member 15d between the sheets. When the toner T alone is used, toner shortage tends to occur when an image of the next page is formed. However, as in Embodiment 5, the toner T is supplied from the toner supply member 15d to the toner carrier 16d between the sheets after the image formation is completed. By generating a supply bias to be moved, the ability to supply toner from the toner supply member 15d to the toner carrier 16d can be increased, so that the supply of the toner carrier 16d can be further improved.

(Embodiment 6) A power supply control unit 30 according to the image forming apparatus 100e of the present invention shown in FIGS.
The characteristic feature of the sixth embodiment is that, after the supply power source 33e generates a peeling bias during image formation, a supply bias generation time for moving the toner T from the toner supply member 15e toward the toner carrier 16e. The fifth embodiment is similar to the fifth embodiment in the other points.

That is, as shown in FIG. 10, after a peeling bias is generated during image formation, a supply bias for moving the toner T from the toner supply member 15e toward the toner carrier 16e is applied for one rotation of the toner carrier 16e. This is to generate for the above time.

FIG. 11 is a diagram showing the relationship between the supply bias generation time of the toner supply member 15e and the amount of toner on the toner carrier 16e. The supply bias is applied for a time corresponding to one rotation of the toner carrier 16e. Then, the toner carrier 16
It is clear that the amount of toner on e can be recovered to approximately ／ of the amount of toner before image formation, and that the amount of toner has returned to substantially the initial amount of toner if generated for a time equivalent to three revolutions.

Thus, the time required for the power supply control unit 30e to generate the separation bias for moving the toner from the toner carrier 16e toward the toner supply member 15e until the start of the image formation of the next page is set to be equal to one rotation of the toner carrier 16e. The toner supply effect can be further improved as compared with the third embodiment if the time is generated for minutes or more, preferably for three or more rounds.

[0075]

The effects of the present invention described in detail by the above embodiments are as follows.

A high-quality image can be provided for a long period without any development history.

It is possible to provide a smooth and uniform image with low torque by preventing the toner from sticking.

A compact and simple configuration can be obtained.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an embodiment of a main part of an image forming apparatus according to the present invention.

FIG. 2 is a time chart of a development power supply output and a supply power supply output of FIG. 1;

FIG. 3 is a diagram showing a charge amount on a toner carrier of FIG. 1;

FIG. 4 is a time chart similar to FIG. 2 of the second embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a separation bias generation time and a toner charge amount in FIG. 4;

FIG. 6 is a time chart similar to FIG. 2 of the third embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the idling time of the toner carrier and the toner charge amount in FIG. 6;

FIG. 8 is a time chart similar to FIG. 2 of Embodiment 4 of the present invention.

FIG. 9 is a time chart similar to FIG. 2 of the fifth embodiment of the present invention.

FIG. 10 is a time chart similar to FIG. 2 of Embodiment 6 of the present invention.

FIG. 11 is a diagram illustrating a relationship between a supply bias generation time and a toner amount in FIG. 10;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 (ae) Image forming device 10 Developing device 15 (ae) Toner supply member 16 (ae) Toner carrier 17 Toner regulating means 30 (ae) Power supply control unit 31 Power supply means 32 (ae) e) Development power supply 33 (ad) Supply power

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Goo Takayama 3-5-5 Yamato, Suwa-shi, Nagano Prefecture Seiko Epson Corporation

Claims (6)

[Claims] A developing unit for forming an image on the latent image carrier by using a toner; a developing unit for forming an image on the latent image carrier with toner; and transferring the toner image on the latent image carrier to a transfer medium. Power supply means for generating an electric field between the toner carrier and the toner supply member, wherein the power supply means at least between the end of image formation and the start of image formation of the next page. An image forming apparatus capable of generating a plurality of electric fields including an electric field for moving toner from the toner carrier toward the toner supply member. 2. An electric field for moving toner from the toner carrier toward the toner supply member for at least one rotation of the toner carrier before the start of image formation of the next page. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as described above. 3. An apparatus according to claim 1, wherein said power supply means terminates an electric field for moving the toner from the toner carrier toward the toner supply member at the start of image formation of the next page. Item 3. The image forming apparatus according to Item 1 or 2. 4. The image forming apparatus according to claim 1, wherein the power supply generates an electric field for moving the toner from the toner carrier toward the toner supply member before the image formation, and terminates the electric field at the time when the image formation is completed. The image forming apparatus according to claim 1. 5. An image according to claim 4, wherein said power supply means generates an electric field in which the toner can move from the toner supply member toward the toner carrier after the image formation is completed. Forming equipment. 6. The apparatus according to claim 5, wherein said power supply means generates an electric field capable of moving the toner from the toner supply member toward the toner carrier for at least one turn of the toner carrier. The image forming apparatus as described in the above.