JPH1115246A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the level difference of density from being formed on a printed image by preventing the density from being fluctuated between the upper stage part and the lower stage part of the printing surface of a printing paper. SOLUTION: This developing device is provided with a toner carrier 13 disposed to face an image carrier and set for supplying toner to the image carrier, a toner supply roller disposed to abut on the carrier 13, a toner layer forming means disposed on a more downstream side than the toner supply roller in the rotating direction of the carrier 13, made to abut on the carrier 13 and set for thinning the layer of the toner and an auxiliary roller 22 disposed to abut on the toner supply roller. Thus, when a developing action is started and the toner is moved to the image carrier from the carrier 13, the toner is scarcely left on the carrier 13. Besides, the quantity of the toner on the carrier 13 before it is passed through an abutting part P2 between the toner supply roller and the carrier 13 becomes almost zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic printer, an electrostatic latent image is formed by irradiating light onto the surface of a photosensitive drum uniformly and uniformly charged, and the electrostatic latent image is formed by a developing device. The toner image is developed, and the toner image is transferred to a printing paper and fixed. FIG. 2 is a conceptual diagram of a conventional developing device, and FIG. 3 is a conceptual diagram of a conventional electrophotographic printer.

In FIG. 1, reference numeral 15 denotes a photosensitive drum, and 57 denotes a charging roller disposed opposite to the photosensitive drum 15 to uniformly and uniformly charge the surface of the photosensitive drum 15. A print head 53 disposed downstream of the charging roller 57 in the rotation direction of the photosensitive drum 15 to irradiate light on the surface of the photosensitive drum 15 to perform exposure to form an electrostatic latent image; 54 is the photosensitive drum 15
A developing device disposed downstream of the print head 53 in the rotation direction of the developing device to develop the electrostatic latent image into a toner image;
55 is disposed downstream of the developing device 54 in the rotation direction of the photoconductor drum 15, is brought into contact with the photoconductor drum 15, and the printing paper 56 conveyed between the photoconductor drum 15 and the The transfer roller transfers a toner image.

The photosensitive drum 15 is rotated counterclockwise in the figure, and the transfer roller 55 and the charging roller 57 are rotated clockwise in the figure. The developing device 54 is made of an elastic material and a toner carrier 13 that is brought into contact with the photosensitive drum 15.
3 has a sponge roller 11, a developing blade 14, a toner cartridge 58, and a toner stirring (stirring) shaft 59. The sponge roller 11 and the toner carrier 13 are rotated clockwise in FIG. Can be

[0005] The toner cartridge 58 has a double pipe structure, and the opening formed in the outer pipe 58a and the opening formed in the inner pipe 58b are aligned with each other so that the toner cartridge 58 can be inserted into the toner cartridge 58. The stored toner (not shown) can be dropped in the direction of the arrow. Below the toner cartridge 58, a toner stirring shaft 59 is provided.
Reference numeral 9 agitates the toner dropped from the toner cartridge 58. Further, the developing blade 14 is brought into contact with the toner carrier 13 by a constant pressure.

In the electrophotographic printer having the above configuration, when a main motor (not shown) starts driving, the sponge roller 11 and the toner carrier 13 are rotated clockwise, and the toner stirring shaft 59 is rotated counterclockwise. At the same time, a negative polarity bias voltage is applied to the sponge roller 11 and the toner carrier 13. Then, the toner dropped from the toner cartridge 58 is transferred to the sponge roller 1 by the toner stirring shaft 59.
1 is supplied. Since a negative bias voltage is applied to the sponge roller 11, the supplied toner adheres to the surface of the sponge roller 11 and is charged to a negative polarity.

Since the bias voltage applied to the toner carrier 13 has a greater absolute value than the bias voltage applied to the sponge roller 11, the toner adhering to the surface of the sponge roller 11 Move to the surface. The toner attached to the surface of the toner carrier 13 is thinned by the developing blade 14 to form a toner layer, and is further charged to a negative polarity by friction.

On the other hand, at the same time as the main motor starts driving, a voltage of negative polarity is applied to the charging roller 57, and the photosensitive drum 1 in contact with the charging roller 57
5 is uniformly and uniformly charged to a negative polarity. Subsequently, when the surface of the photosensitive drum 15 is irradiated with light by the print head 53, the charge level of the irradiated part is reduced to around 0 [V], and the photosensitive drum 1 is charged.
An electrostatic latent image is formed on the surface of No. 5. In this case, since the toner on the surface of the toner carrier 13 is charged to a negative polarity, it adheres to the electrostatic latent image formed on the surface of the photosensitive drum 15. On the other hand, the part that is not irradiated with light is
Since the toner is charged to a negative polarity at a higher level than the toner, the toner does not adhere.

As described above, the electrostatic latent image formed on the surface of the photosensitive drum 15 is developed by being attached with toner to become a toner image. Then, the printing paper 56
When a voltage having a positive polarity opposite to the polarity of the toner is applied to the transfer roller 55 when the toner image passes between the photosensitive drum 15 and the transfer roller 55, the toner image on the photosensitive drum 15 is Transferred to 56.

Thereafter, the toner image transferred to the printing paper 56 is fixed by a fixing device (not shown). After the transfer, the toner remaining on the surface of the photosensitive drum 15 is removed by a cleaning device (not shown). Incidentally, the sponge roller 11 and the toner carrier 13 are
At the contact portion P1, the outer peripheral surfaces are rotated so as to move in opposite directions. And the sponge roller 11
Supplies toner to the toner carrier 13 and charges the toner by friction between the sponge roller 11 and the toner carrier 13 on the upstream side of the contact portion P1 in the rotation direction. On the downstream side of the contact portion P1 in the direction, the toner remaining on the toner carrier 13 after development is scraped off.

When the bias voltage applied to the sponge roller 11 and the toner carrier 13 is set to an appropriate value,
The amount of toner supply and the amount of scraping by the sponge roller 11 can be adjusted. For example, if the toner is charged to a negative polarity and the bias voltage applied to the toner carrier 13 is V2 and the bias voltage applied to the sponge roller 11 is V1, (| V2 |-| V1 | )
Is larger, the supply amount of the toner to the toner carrier 13 is larger.

The developing blade 14 is brought into contact with the toner carrier 13 at a constant pressure, and selects only toner charged on the toner carrier 13 at a certain level or more from the toner layer 13 to form a toner layer. Is thinned. In this case, when the supply amount of the toner from the sponge roller 11 to the toner carrier 13 increases, the amount of toner charged above a certain level increases, so that the toner layer after passing through the developing blade 14 becomes thicker.

[0013]

However, in the conventional developing device, for example, when solid black printing is performed, the density in the first half area, that is, the upper part, and the second half area, that is, the lower part, of the printing surface of the printing paper 56 is reduced. Fluctuates, and a density step is formed in the printed image. Next, the generation mechanism of the concentration step will be described.

FIG. 4 is an explanatory view showing a mechanism for supplying toner from a sponge roller to a toner carrier in a conventional developing device, and FIG. 5 is a first diagram showing a mechanism for generating a density step in solid black printing in a conventional developing device. Illustration of FIG. 6
FIG. 7 is a second explanatory view showing the mechanism of the occurrence of the density step in the conventional developing device during solid black printing, and FIG. 7 is the third explanatory view showing the mechanism of the occurrence of the density step in the conventional developing apparatus during solid black printing. is there.

As shown in the figure, the sponge roller 11
In the supply section a1 upstream of the contact section P1 in the rotational direction, the toner is supplied to the toner carrier 13 and the toner is charged by friction. On the other hand, the scraping section downstream of the contact section P1 in the rotational direction is provided. In the section b1, the toner remaining on the toner carrier 13 after development is scraped off.

The toner scraped off from the toner carrier 13 adheres to the sponge roller 11, moves with the rotation of the sponge roller 11, is sent in the direction of arrow E, and is again transferred to the toner carrier. 13 is supplied. Therefore,
Assuming that the amount of toner scraped from the toner carrier 13 and adhered to the sponge roller 11 is T _1, and the amount of toner that is wound around the supply unit a 1 from the surroundings as the sponge roller 11 rotates is T ₂ , The amount of toner supplied to the toner carrier 13 by the roller 11 is (T ₁ + T ₂ )
become.

Here, assuming that the development is started from a point A on the toner carrier 13 as shown in FIG. 5, the toner carrier 13 rotates and the point A comes into contact as shown in FIG. When the toner carrier 13 moves to the position P1, the toner on the toner carrier 13 adheres to the photosensitive drum 15 by development, so that a small amount of toner remains on the toner carrier 13 upstream of the point A in the rotation direction of the toner carrier 13. You just do.

Therefore, if the point on the sponge roller 11 that contacts the point A is B, when the area upstream of the point B in the rotation direction of the sponge roller 11 reaches the scraping section b1, the area at the scraping section b1 the amount T ₁ of the toner adhering to the sponge roller 11 with the scraping of the toner from the toner carrier 13 is significantly less, becomes substantially zero. Then, as shown in FIG. 7, after the sponge roller 11 makes one rotation and the point B reaches the contact portion P1, the supply portion a
In 1, the amount of toner supplied to the toner carrier 13 is almost T ₂ , which is extremely small.

Therefore, if the point on the toner carrier 13 at the time when the point B reaches the contact portion P1 is D, the toner carrier on the upstream side of the point D in the rotation direction of the toner carrier 13 13, the amount of toner attached to the toner 13 decreases, and the toner layer becomes thinner. As described above, since the supply amount of the toner from the sponge roller 11 to the toner carrier 13 fluctuates, the density fluctuates between the upper part and the lower part of the printing surface of the printing paper 56 (FIG. 3), and the density of the printed image is changed. A step is formed.

The present invention solves the problems of the conventional developing device, prevents the density from fluctuating between the upper part and the lower part of the printing surface of the printing paper, and forms a density step on the printed image. It is an object of the present invention to provide a developing device that does not have any problem.

[0021]

For this purpose, in the developing device of the present invention, a toner carrier, which is disposed to face the image carrier and supplies toner to the image carrier, and which is in contact with the toner carrier. A toner supply roller disposed in contact with the toner supply roller, and a toner layer disposed downstream of the toner supply roller in the rotation direction of the toner carrier and in contact with the toner carrier to reduce the thickness of the toner. The image forming apparatus includes a forming unit and an auxiliary roller provided in contact with the toner supply roller.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram of a developing device according to the first embodiment of the present invention. In the figure, reference numeral 25 denotes a developing device.
A toner carrier 13, which is provided to face the photoconductor drum 15 as an image carrier and supplies toner (not shown) to the photoconductor drum 15, is made of an elastic material, and is disposed in contact with the toner carrier 13. A sponge roller 21 provided as a toner supply roller, and a toner layer disposed downstream of the sponge roller 21 in the rotation direction of the toner carrier 13 and brought into contact with the toner carrier 13 to make toner thinner A developing blade 14 as a forming means, and an auxiliary roller 2 disposed in contact with the sponge roller 21
2. It has a toner cartridge 58 (see FIG. 3) and a toner stirring shaft 59. The toner carrier 13 and the sponge roller 21 are brought into contact with each other at a contact portion P2, and the sponge roller 21 and the auxiliary roller 22 are brought into contact with each other at a contact portion P3. The auxiliary rollers 22 are respectively rotated clockwise in the figure, counterclockwise in the figure. Therefore, at the contact portion P2, the toner carrier 13
And the outer peripheral surface of the sponge roller 21 are moved in opposite directions, and the outer peripheral surface of the toner supply roller 21 and the outer peripheral surface of the auxiliary roller 22 are moved in the forward direction at the contact portion P3.

The peripheral speed of the toner carrier 13 and that of the sponge roller 21 are different. The auxiliary roller 22 is connected to the sponge roller 2 via a gear (not shown).
The sponge roller 21 and the auxiliary roller 22 have different peripheral speeds.
As the auxiliary roller 22, a stainless roller, an aluminum roller, a conductive rubber roller, or the like, which is conductive and has a smooth surface, is used. Among them, it is particularly preferable to use a metal roller such as a stainless roller or an aluminum roller. In other words, when a material having a smooth surface is used, the frictional force with the sponge roller 21 can be reduced, so that the abrasion of the sponge roller 21 can be prevented.

The sponge roller 21 supplies the toner to the toner carrier 13 at a supply section a2 upstream of the contact portion P2 in the rotation direction, and the toner is generated by friction between the toner carrier 13 and the sponge roller 21. Is charged, and on the other hand, in the scraping portion b2 downstream of the contact portion P2 in the rotation direction, the toner remaining on the toner carrier 13 after development is scraped.

The toner scraped off from the toner carrier 13 adheres to the sponge roller 21, moves with the rotation of the sponge roller 21, and is supplied to the toner carrier 13 again. In the developing device 25 having the above configuration, when the development is started and the toner moves from the toner carrier 13 to the photosensitive drum 15, the toner hardly remains on the toner carrier 13. Therefore, the amount of toner on the toner carrier 13 before passing through the contact portion P2 becomes almost zero.

However, on the sponge roller 21, since toner is supplied by the auxiliary roller 22 at the contact portion P3 even after the development is started, the toner passes through the contact portion P3 and then passes through the contact portion P2. Before the operation, the amount of toner on the sponge roller 21 does not become zero. Therefore, it is possible to prevent the density from fluctuating between the upper part and the lower part of the printing surface of the printing paper 56, so that the density step is not formed in the printed image.

In this case, a voltage is applied to the auxiliary roller 22. However, the sponge roller 2 may be electrically floated without applying a voltage.
1 can be supplied with toner. For example, when a bias voltage of 300 [V] is applied to the toner carrier 13, a bias voltage of 450 [V] is applied to the sponge roller 21, and a bias voltage of 500 [V] is applied to the auxiliary roller 22, respectively, Since the positive polarity toner remaining on the photosensitive drum 15 can be collected by the auxiliary roller 22, the printing paper 56 is not stained by the positive polarity toner.

FIG. 8 is a first characteristic diagram of the developing device according to the first embodiment of the present invention. In the drawing, the horizontal axis represents the speed ratio between the rotation speed of the auxiliary roller 22 (FIG. 1) and the rotation speed of the sponge roller 21, and the vertical axis represents the toner formed on the toner carrier 13 with the start of development. The difference in layer thickness is taken. In the figure, L1 is a line showing the relationship between the speed ratio and the layer thickness difference when the nip amount between the auxiliary roller 22 and the sponge roller 21 is 0.5 [mm], and L2 is the nip amount of 0.29 [mm]. [mm] is a line showing the relationship between the speed ratio and the layer thickness difference when [mm].

As shown in the figure, when the speed ratio is set to 0.5 and the nip amount is set to 0.5 [mm], the layer thickness difference can be minimized. Next, a comparison result between the conventional developing device 54 (see FIG. 3) and the developing device 21 in the first embodiment will be described. FIG. 9 is a second characteristic diagram of the developing device according to the first embodiment of the present invention. In the drawing, the structure of the developing devices 25 (FIG. 1) and 54 (see FIG. 3) is plotted on the X axis, the number of prints is plotted on the Y axis, and the layer thickness difference is plotted on the Z axis. In this case, the speed ratio was set to 0.5, and the nip amount was set to 0.5 [mm].

As shown in the figure, in the developing device 21 according to the first embodiment, the layer thickness difference can be made smaller than in the conventional developing device 54. In the present embodiment, a urethane rubber roller is used as the toner carrier 13, a silicone sponge roller is used as the sponge roller 21, and a stainless steel roller is used as the auxiliary roller 22.

Next, a second embodiment of the present invention will be described. FIG. 10 is a conceptual diagram of a developing device according to the second embodiment of the present invention. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol. In this case, the auxiliary roller 23 is a sponge roller 21 as a toner supply roller.
The sponge roller 2 is rotated counterclockwise similarly to
At the contact portion between the roller 1 and the auxiliary roller 23, the outer peripheral surface of the sponge roller 21 and the outer peripheral surface of the auxiliary roller 23 are moved in opposite directions. Therefore, the toner charging effect due to the friction between the sponge roller 21 and the auxiliary roller 23 can be improved, and the sufficiently charged toner can be supplied to the toner carrier 13 and used for development. In addition, it is possible to prevent the background fog from occurring on the printing paper 56 (see FIG. 3).

Next, a comparison result between the conventional developing device 54 and the developing device 25 in the second embodiment will be described. FIG. 11 is a characteristic diagram of the developing device according to the second embodiment of the present invention. In the drawing, the structures of the developing devices 25 (FIG. 10) and 54 (see FIG. 3) are plotted on the X axis, the number of prints is plotted on the Y axis, and the layer thickness difference is plotted on the Z axis. In this case, the speed ratio was set to 0.5, and the nip amount was set to 0.5 [mm].

As shown in the figure, in the developing device 25 according to the second embodiment, the layer thickness difference can be made smaller than in the conventional developing device 54. In this embodiment, a urethane rubber roller is used as the toner carrier 13, a silicone sponge roller is used as the sponge roller 21, and a stainless roller is used as the auxiliary roller 23.

Next, a third embodiment of the present invention will be described. FIG. 12 is a conceptual diagram of a developing device according to the third embodiment of the present invention, and FIG. 13 is a perspective view of an auxiliary roller according to the third embodiment of the present invention. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol.

In this case, the auxiliary roller 24 is rotated clockwise, and at the contact portion between the sponge roller 21 as a toner supply roller and the auxiliary roller 24, the outer peripheral surface of the sponge roller 21 and the outer periphery of the auxiliary roller 24 The plane is moved in the forward direction. In addition, knurling is performed on the outer peripheral surfaces of both ends of the auxiliary roller 24 with a predetermined width to form irregularities.

Therefore, even if the deteriorated toner which has increased in the number of printed sheets enters the cells (not shown) at both ends of the toner carrier 13, the toner can be scraped off by the auxiliary roller 24. This can be prevented from occurring. As a result, the toner can be stably supplied to the toner carrier 13. In this embodiment, the auxiliary roller 24 is configured to be rotated clockwise, but may be rotated counterclockwise.

Next, a fourth embodiment of the present invention will be described. FIG. 14 is a conceptual diagram of a developing device according to the fourth embodiment of the present invention. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching the same code | symbol. In this case, sponge rollers 21 and 31 as toner supply rollers are provided in contact with the toner carrier 13, and an auxiliary roller 22 is provided in contact with the sponge roller 21.
The sponge roller 31 is disposed downstream of the sponge roller 21 in the rotation direction of the toner carrier 13, and the sponge roller 21 and the toner carrier 13 contact each other at a contact portion P2. 13 are brought into contact with each other at a contact portion P4. Then, the sponge roller 21 and the auxiliary roller 22 contact at the contact portion P3.

The toner carrier 13 and the sponge rollers 21 and 31 are rotated counterclockwise in the figure, and the auxiliary roller 22 is rotated clockwise in the figure. Accordingly, the outer peripheral surface of the toner carrier 13 and the outer peripheral surface of the sponge roller 21 are moved in opposite directions at the contact portion P2, and the outer peripheral surface of the toner carrier 13 and the outer periphery of the sponge roller 31 are moved at the contact portion P4. The outer peripheral surface of the sponge roller 21 and the outer peripheral surface of the auxiliary roller 22 are moved in the forward direction at the contact portion P3.

Then, the sponge roller 21 is provided at a supply portion a2 upstream of the contact portion P2 in the rotation direction.
The toner is supplied to the toner carrier 13 and the toner is charged by friction. On the other hand, in the scraping portion b2 downstream of the contact portion P2 in the rotation direction, the toner remaining on the toner carrier 13 after development is scraped. To take. At this time, the toner scraped from the toner carrier 13 adheres to the sponge roller 21 and the sponge roller 2
It moves with the rotation of 1 and is again supplied to the toner carrier 13.

Further, the sponge roller 31 supplies the toner to the toner carrier 13 and charges the toner by friction at the supply section a3 upstream of the contact section P4 in the rotation direction. At a scraping portion b3 downstream of the contact portion P4, the toner remaining on the toner carrier 13 after development is scraped. At this time, the toner scraped from the toner carrier 13 adheres to the sponge roller 22 and the sponge roller 2
2 and is supplied to the toner carrier 13 again.

Then, the development is started and the toner carrier 1
When the toner moves from 3 to the photosensitive drum 15 as an image carrier, the toner hardly remains on the toner carrier 13. Therefore, the amount of toner on the toner carrier 13 before passing through the contact portion P2 becomes almost zero. However, on the sponge roller 21, the toner is supplied by the auxiliary roller 22 at the contact portion P3 even after the development is started, so that the toner passes through the contact portion P2 and passes through the contact portion P4. Before the toner carrier 13
The sponge roller 21 supplies a sufficient amount of toner. Therefore, it is possible to prevent the density from fluctuating between the upper part and the lower part of the printing surface of the printing paper 56 (see FIG. 3), so that a density step is not formed in the printed image.

In the present embodiment, the sponge roller 31 is arranged downstream of the sponge roller 21 in the rotation direction of the toner carrier 13, but is arranged upstream of the sponge roller 21. You can also. Further, in the present embodiment, the auxiliary roller 22 is arranged to be in contact with the sponge roller 21, but may be arranged to be in contact with the sponge roller 31. Further, the sponge roller 21 and the sponge roller 31 can be disposed in contact with at least one of them.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0044]

As described above in detail, according to the present invention, in a developing device, a toner carrier provided to face an image carrier and supplying toner to the image carrier, and the toner A toner supply roller disposed in contact with the carrier, and a toner supply roller disposed downstream of the toner supply roller in the rotation direction of the toner carrier, and brought into contact with the toner carrier to form a thin layer of toner. Means for forming a toner layer,
And an auxiliary roller disposed in contact with the toner supply roller.

In this case, when the development is started and the toner moves from the toner carrier to the image carrier, the toner hardly remains on the toner carrier. Then, the amount of toner on the toner carrier before passing through the contact portion between the toner supply roller and the toner carrier becomes almost zero. However,
On the toner supply roller, the toner is supplied by the auxiliary roller even after the development is started, so that the toner before passing through the contact portion with the auxiliary roller and before passing through the contact portion with the image carrier is used. The amount of toner on the supply roller does not become zero. Therefore, it is possible to prevent the density from fluctuating between the upper part and the lower part of the printing surface of the printing paper, so that the density step is not formed in the printed image.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a developing device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional developing device.

FIG. 3 is a conceptual diagram of a conventional electrophotographic printer.

FIG. 4 is an explanatory diagram showing a mechanism for supplying toner from a sponge roller to a toner carrier in a conventional developing device.

FIG. 5 is a first explanatory view showing a mechanism of occurrence of a density step during solid black printing in a conventional developing device.

FIG. 6 is a second explanatory diagram showing a mechanism of occurrence of a density step during solid black printing in a conventional developing device.

FIG. 7 is a third explanatory diagram illustrating a mechanism of generating a density step in solid black printing in a conventional developing device.

FIG. 8 is a first characteristic diagram of the developing device according to the first embodiment of the present invention.

FIG. 9 is a second characteristic diagram of the developing device according to the first embodiment of the invention.

FIG. 10 is a conceptual diagram of a developing device according to a second embodiment of the present invention.

FIG. 11 is a characteristic diagram of a developing device according to a second embodiment of the present invention.

FIG. 12 is a conceptual diagram of a developing device according to a third embodiment of the present invention.

FIG. 13 is a perspective view of an auxiliary roller according to a third embodiment of the present invention.

FIG. 14 is a conceptual diagram of a developing device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Toner carrier 14 Developing blade 15 Photoreceptor drum 21, 31 Sponge roller 22-24 Auxiliary roller 25 Developing device P3 Contact part

Continuing from the front page (72) Inventor Tetsuji Kojima 4-11-11 Shibaura, Minato-ku, Tokyo Within the offshore data of the corporation (72) Inventor Osamu Teramura 1-1-1 Tatsuda, Shono, Fukushima-shi, Fukushima Prefecture 1 offshore data of the corporation In Systems

Claims (5)

[Claims] 1. (a) disposed to face an image carrier,
A toner carrier for supplying toner to the image carrier, (b) a toner supply roller disposed in contact with the toner carrier, and (c) a toner supply roller in a rotation direction of the toner carrier. A toner layer forming unit disposed downstream and in contact with the toner carrier to reduce the thickness of the toner; and (d) an auxiliary roller disposed in contact with the toner supply roller. A developing device, characterized in that: 2. The developing device according to claim 1, wherein an outer peripheral surface of the toner supply roller and an outer peripheral surface of the auxiliary roller are moved in a forward direction at a contact portion between the toner supply roller and the auxiliary roller. 3. The developing device according to claim 1, wherein an outer peripheral surface of the toner supply roller and an outer peripheral surface of the auxiliary roller are moved in opposite directions at a contact portion between the toner supply roller and the auxiliary roller. 4. The developing device according to claim 1, wherein the auxiliary roller is partially formed with irregularities. 5. A plurality of the toner supply rollers are provided in contact with the toner carrier, and (b) the auxiliary roller is brought into contact with at least one of the toner supply rollers. Any one of claims 1 to 4,
Item 6. The developing device according to item 1.