JP2002251066A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of improving image quality by realizing the prevention of fogging and the improvement of the reproducibility of a thin line by improving the electrification property of toner on a developing roller. SOLUTION: A tackiness value is used as an index, and a chip part 482 is formed of material having the comparatively large tackiness value, then a regulating blade 48 constituted by using the chip part 482 is made to abut on the developing roller 47. By constituting in such away, the adhesive force of the chip part 482 and the toner is enhanced, so that the toner is rotated and stirred on the surface of the chip part 482 and the electrification property of the toner is improved. By such constitution, the developing device capable of improving the image quality by realizing the prevention of fogging and the improvement of the reproducibility of a thin line is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, a copying machine, a facsimile machine, and the like for visualizing an electrostatic latent image formed on an image carrier such as a photosensitive drum or a photosensitive belt by attaching toner to the latent image. And a developing device used in the electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art As a developing device of this type, there is a one-component developing system using one-component toner. For example, such a developing device forms a thin layer of non-magnetic toner on the surface of a developing roller (developing sleeve) and brings the thin layer into contact with the surface of a photosensitive drum as an image carrier at a predetermined developing position. It is configured to perform. More specifically, the developing roller is configured to elastically contact the photosensitive drum with a nip width due to deformation and to convey the toner to a developing position facing the image carrier. . A supply roller (toner supply body) is provided on the opposite side of the development roller from the development position.
The non-magnetic one-component toner stored in the toner storing section provided in the developing device main body is supplied to the developing roller. The developing roller is provided with a regulating blade such that the leading end of the developing roller contacts the developing roller. The regulating blade regulates the amount of toner transported to the developing position by the developing roller. A thin layer of toner is formed on the surface. The toner thus formed is transported to the developing position to develop the latent image on the photosensitive drum.

[0003]

By the way, in the developing device constructed as described above, stripes and density unevenness occur in the longitudinal direction of the formed image (peripheral direction of the developing roller) due to long-term use. As a result, image quality may be degraded. One of the causes of such deterioration in image quality is considered to be friction between toners and adhesion of toner to the regulating blade. Therefore, conventionally, the contact pressure of the regulating blade with respect to the developing roller is set to be small to reduce the adhesion of the toner to the regulating blade and improve the image quality.

However, when the contact pressure of the regulating blade is set to a small value as described above, the friction between the toners and the adhesion of the toner to the regulating blade are reduced, but the charging of the toner on the developing roller becomes insufficient. Image deterioration such as fogging and a decrease in fine line reproducibility may occur.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and has been made to improve the chargeability of the toner on the developing roller, thereby preventing fog and improving reproducibility of fine lines. It is another object of the present invention to provide a developing device capable of improving image quality.

[0006]

In order to achieve the above object, a developing device according to the present invention rotates a toner carrier while carrying the toner, thereby conveying the toner to a developing position opposed to the image carrier. Regulating means for contacting the toner carrier to regulate the amount of toner transported to the toner carrier to form a thin charged toner layer on the surface of the toner carrier; The contact portion of the regulating means contacting the toner is formed using a material having a tack value indicating an adhesive force with the toner of 750 mN or more and 1500 mN or less.

Here, the tack value can be measured as follows. First, the toner is pressed to form a pellet-shaped toner probe (), and the toner probe enters a sample (a piece of material forming a contact portion) at a predetermined pushing speed, for example, a speed of 30 mm / min. Then, a predetermined pressure is applied to the sample (a compressive force is applied to the sample) (). Thereafter, the toner probe is separated from the sample at a predetermined separation speed, for example, at a speed of 600 mm / min, until the sample is torn or the toner probe is separated from the sample (a tensile force is applied to the sample).
(). Then, the maximum tensile force applied to the toner probe when the toner probe is separated from the sample is defined as a tack value ().

In the developing device having such a configuration, a material having a relatively large adhesive force with the toner (a material having a tack value of 750 mN or more and 1500 mN or less) can be easily obtained by using one index called a tack value. Since the contact portion is formed by using this material, the adhesive force between the contact portion and the toner increases, and the toner is rotated and stirred on the contact portion,
The chargeability of the toner is improved. As a result, fog can be prevented and fine line reproducibility can be improved, and image quality can be improved.

Also, the tack value can be measured as follows. First, the toner is pressed to form a pellet-shaped toner probe (), and the toner probe enters a sample (a piece of material forming a contact portion) at a predetermined pushing speed, for example, a speed of 30 mm / min. Then, a predetermined pressure is applied to the sample (a compressive force is applied to the sample) (). Thereafter, until the sample is torn, or until the toner probe separates from the sample, the toner probe is separated at a predetermined separation speed,
For example, the sample is separated from the sample at a speed of 600 mm / min (tensile force is applied to the sample) (). Then, the maximum tensile force applied to the toner probe when the toner probe is separated from the sample is defined as a tack value (). Then, instead of the toner probe, a probe made of metal, resin, or ceramics having the same shape (hereinafter, referred to as “alternate probe”) is used, and a tack value (hereinafter, “preliminary tack value”) is obtained in the same manner as above.
That. ) Is determined (), and a correlation between the tack value obtained using the toner probe and the preliminary tack value obtained using the substitute probe is found (). Then, after finding these correlations, a tack value obtained using the toner probe, or a tack value obtained based on the preliminary tack value and the correlation,
This is the tack value of the sample ().

According to such a measuring method, after finding the correlation, the material for forming the contact portion can be selected by using the substitute probe without using the toner probe. . The use of the substitute probe makes it easier to handle the probe than the case of using the toner probe, which is liable to be damaged, and enables the tack value to be measured in a short time.

[0011]

FIG. 1 is a view showing an image forming apparatus equipped with an embodiment of a developing device according to the present invention. In this image forming apparatus, a photoreceptor 2 is provided in an apparatus main body 1 so as to be rotatable in an arrow direction D1 in FIG. Further, around the photosensitive member 2 along the rotation direction D1,
A charger 3 as a charging unit, a rotary developing unit 4 as a developing unit, and a cleaning unit 5 are arranged. The charger 3 is applied with a charging bias from a charging bias circuit (not shown), and uniformly charges the outer peripheral surface of the photoconductor 2.

Then, a laser beam L is emitted from the exposure unit 6 toward the outer peripheral surface of the photosensitive member 2 charged by the charger 3. The exposure unit 6 performs laser beam L irradiation according to image data obtained by developing an image forming command into an image.
On the photoreceptor 2 to form an electrostatic latent image on the photoreceptor 2 corresponding to the image forming command.

The electrostatic latent image thus formed is developed by the developing unit 4 with toner. That is, in this embodiment, the developing unit 4 is used as the developing unit 4 for black.
K, a developing device 4C for cyan, a developing device 4M for magenta,
And a developing unit 4Y for yellow is rotatably provided about the axis. These developing units 4K, 4C, 4M, 4Y
Is rotated and positioned, and selectively contacts the photoconductor 2 to apply toner to the surface of the photoconductor 2. As a result, the electrostatic latent image on the photoconductor 2 is visualized in the selected toner color. In this embodiment, the photoconductor 2 functions as the “image carrier” of the present invention. The configuration and operation of the developing unit 4 will be described later.

The toner image developed by the developing unit 4 as described above is transferred to the transfer unit 7 in the primary transfer area TR1.
Is primarily transferred onto the intermediate transfer belt 71. Further, a cleaning unit 5 is disposed at a position where the photoconductor 2 has advanced in the circumferential direction (rotation direction D1 in FIG. 1) from the primary transfer area TR1, and the cleaning unit 5 is provided with the photoconductor 2 after the primary transfer.
The toner remaining on the outer peripheral surface of the toner is scraped off.

The transfer unit 7 includes an intermediate transfer belt 71 stretched over a plurality of rollers, and a driving unit (not shown) for driving the intermediate transfer belt 71 to rotate. When the color image is to be transferred to the sheet member S, the color images are formed by superimposing the toner images of the respective colors formed on the photoreceptor 2 on the intermediate transfer belt 71, and a predetermined secondary transfer area is formed. In TR2, a color image is secondarily transferred onto the sheet member S taken out of the cassette 8.
The sheet member S on which the color image has been formed is conveyed via the fixing unit 9 to the discharge tray section 11 provided on the upper surface of the apparatus main body 1.

Next, the configuration and operation of the rotary developing unit 4 provided in the image forming apparatus of FIG. 1 will be described in detail. FIG. 2 is a view showing a rotary developing unit as an embodiment of the developing device according to the present invention. FIG. 3 is a partially enlarged view of the developing device of FIG. As shown in FIG. 2, the rotary developing unit 4 has a rotating shaft 4a at the center thereof and a support frame 4b fixed to the rotating shaft 4a, and the above-described four-color developing units 4K and 4C. , 4M, and 4Y are fixed radially around a rotating shaft 4a to a support frame 4b by fixtures (not shown). A drive unit (not shown) is connected to the rotation shaft 4a via a clutch. By driving the drive unit, the support frame 4b is rotated, and the four developing units 4K, 4C, 4M, and 4Y are driven. One developing unit can be selectively positioned at a developing position DP (FIG. 3) facing the photoconductor 2.

The developing units 4K, 4C, 4M, and 4Y held on the support frame 4b have the same configuration. Therefore, here, the configuration of the developing unit 4K will be described in detail, and the other developing units 4C, 4M, and 4Y will be denoted by the same reference numerals, and the description of the configuration will be omitted.

In the developing device 4K, two housing members 4
1, 42 are integrally combined to form a housing 43 serving as a main body of the developing device 4K. Since the toner T is accommodated in the housing 43, the toner accommodating space inside the housing 43 becomes the toner accommodating portion 44.

A supply roller 46 is disposed in the toner container 44 and rotates while being in contact with a developing roller 47 which is driven to rotate at the most distal end of the housing 43. The developing roller 47 carries the toner T supplied from the supply roller 46 and rotates while being in contact with the photoconductor 2, and causes the toner T to adhere to the surface of the photoconductor 2 at the developing position DP (FIG. 3). In this manner, the black toner T is rubbed against the surface of the developing roller 47 to have a predetermined thickness (for example, several μm).
m to several hundred μm) is formed on the surface of the developing roller 47. In this embodiment, the developing roller 47 functions as the “toner carrier” of the present invention.

A regulating blade corresponding to "regulating means" of the present invention is provided at a contact position CP between the supply roller 46 and the developing roller 47 and a contact position EP (FIG. 3) sandwiched between the developing position DP. 48 are arranged. This regulation blade 4
8 is a plate-shaped member 4 made of stainless steel, phosphor bronze, or the like.
81 and a chip portion 482 made of rubber, a resin member, or the like attached to the distal end of the plate-shaped member 481. In this embodiment, the tip part 482 functions as the “contact part” of the present invention.

The rear end of the plate member 481 is fixed to the housing member 41 in a so-called counter state.
That is, in the rotation direction D2 of the developing roller 47, the tip portion 482 attached to the tip end of the plate-shaped member 481.
Are disposed on the upstream side of the rear end of the plate-shaped member 481. The tip portion 482 is elastically abutted against the surface of the developing roller 47 at the abutting position EP in an abdominal contact state (see FIG. 3). Here, the “belly contact state” refers to a contact position EP between the chip portion 482 and the developing roller 47 at a position away from the vicinity of the edge of the chip portion 482.
Is set. In addition, regulation blade 4
8 indicates that the tip portion 482 is
It is fixed to the housing member 41 so as to apply a contact pressure of about 94.20 mN / cm (30 gf / cm). The thickness of the toner layer formed on the surface of the developing roller 47 by the regulating blade 48 provided in this way is finally regulated to about several μm to several hundred μm. At this time, the toner is charged to the same polarity even by friction with the regulating blade 48. In this way, the toner T charged to a predetermined polarity with respect to the developing roller 47 is supplied to the developing position DP, and the electrostatic latent image on the photoconductor 2 can be developed by the toner T on the developing roller 47.

In this embodiment, as described above, since the regulating blade 48 is abutted against the developing roller 47 at a relatively low pressure (approximately 294.20 mN / cm), the tip portion 482 The stress generated between the developing roller 47 and the developing roller 47 is reduced to prevent deterioration of the toner,
Sticking of the toner to the developing roller 47 and the chip portion 482 can be effectively reduced. In such a configuration, the chargeability of the toner greatly differs depending on the properties of the material for forming the chip portion 482, that is, the adhesive force between the chip portion 482 and the toner. A tack value is used when selecting a material for forming the portion 482, and the tip portion 482 is formed using a material having a relatively large tack value. Here, the “tack value” is an index indicating the adhesive force between the chip portion 482 and the toner, and is measured by a method as shown in FIG. 4 below in the present embodiment.

FIG. 4 is a schematic diagram for explaining a method of measuring a tack value. In the present embodiment, the tack value is measured using a tacking tester manufactured by Resca Co., Ltd., and a material for forming the tip portion 482 is selected based on the tack value.

In FIG. 4, as a sample 101,
One of the material pieces that may be used to form the tip portion 482 is prepared, and the probe 102 is prepared by compressing toner into a pellet (hereinafter referred to as “toner probe”). . Here, (a) to (h) on the lower side of FIG. 4 show the movement of the sample 101 and the toner probe 102 over time in this measurement, and the upper graph of FIG.
4 is a graph showing a load (vertical axis) applied to the device and a time (horizontal axis) during which the load is applied.

In this measuring method, first, the toner probe 102 is brought close to the sample 101 at a predetermined pushing speed (for example, 30 mm / min) (FIG. 4A). Then, the toner probe 102 enters the sample 101 for a predetermined time at this pressing speed (FIG. 4B), and after the toner probe 102 is stopped, a predetermined pressing load (for example, 10 g) (FIG. 4 (c)). Next, the toner probe 102 is separated from the sample 101 at a predetermined separation speed (for example, 600 mm / min) (FIGS. 4 (d) to 4 (g)).
The measurement is terminated when 02 moves away from the sample 101 (FIG. 4 (h)). Here, the “tack value” is the maximum tensile force F (mN) applied to the toner probe 102 when the toner probe 102 is separated from the sample 101.
(See graph in FIG. 4).

Next, the tack values measured for a plurality of samples (samples 1 to 4) and the relationship between the tack values and the fog quality will be described. Here, Sample 1 is a liquid thermosetting urethane rubber, Sample 2 is a silicon-added liquid thermosetting urethane rubber, and Sample 3 is an ethylene propylene diene rubber (EPD).
M), Sample 4 is a polyurethane type urethane rubber. Table 1 below shows the tack values of the samples measured by the above-described measurement method, the hardness and surface roughness of these samples,
It is a summary of fog quality when used as 82. The tack value of these samples was measured using a toner probe having a diameter of 5 mm, and the room temperature during the measurement was 24 ° C. Further, the developing roller 4
7, the contact pressure of the regulating blade 48 is 294.20.
mN / cm (30 gf / cm). Further, the circularity of the toner used in this measurement is 0.98 (FPIA
(Measured value by a flow type particle image analyzer).

[0027]

[Table 1] In the column of “quality of fog” in Table 1 above, “◎” indicates that fog is least generated and is most suitable for use, “○” indicates next good quality, “△” indicates substantially good quality, and “、” indicates fog generation. Are often unsuitable for use with "x".

As is apparent from Table 1, when the tip portion 482 is brought into contact with the developing roller 47 at a low contact pressure as in the present embodiment, the larger the tack value, the less the fog is generated. It can be seen that the image quality is improved.
In other words, it is clear that the larger the tack value, the more the chargeability of the toner can be improved and fogging is prevented, and that the magnitude of the tack value and the quality of the fog have a certain relationship. Therefore, in the present embodiment, it is possible to easily select a material for forming the tip portion 482 based on one index called a tack value.

Specifically, as in the present embodiment, the regulating blade 48 is applied with a relatively low contact pressure (294.20 mN /
cm), 75
It is preferable to use a material having a tack value of 0 mN or more. For example, the urethane rubber of Sample 2 (tack value:
778.7 mN) or the urethane rubber of Sample 1 (tack value: 1176.8 mN).

However, if the chip portion is formed of a material having an excessively large tack value, the movement of the toner in contact with the surface of the chip portion is restricted, and the toner may adhere to the surface of the chip portion. When the toner adheres to the surface of the chip portion in this way, it not only affects the chargeability of the toner, but also has an adverse effect such as filming. Therefore, in the present embodiment, a material having a tack value of 750 mN or more and 1500 mN or less is selected as a material for forming the tip portion 482. If the chip portion 482 is formed using a material having a tack value within such a range, the toner can be appropriately fixed without sticking to the surface of the chip portion 482. Both Sample 1 and Sample 2 are materials having tack values within this range.

As can be seen from Table 1, it is difficult to find a certain relationship between the hardness of each sample and the quality of fog, or between the surface roughness of each sample and the quality of fog. It is difficult to select a material for forming the tip portion 482 based on only the hardness or the surface roughness as in the tack value described above. That is, the hardness certainly affects the frictional force in relation to the nip width of the regulating blade, but it is hard to say that the magnitude of the hardness directly corresponds to the quality of fog (see Table 1). Also, if the surface roughness is increased, the force for mechanically holding the toner increases,
Since the adhesive force to the toner does not depend only on the surface roughness but also greatly depends on the material of the material, it is difficult to say that the surface roughness also directly corresponds to fog (see Table 1). 1). That is, depending on these indices, it was difficult to select the material of the chip portion based on one indices.

As described above, in this embodiment, since the chip portion 482 is formed using a material having a large tack value, that is, a material having a large adhesive force (adhesive force) to the toner, the chip portion 482 is conveyed by the developing roller 47. When the toner passing through the contact portion with the regulating blade 48, the tip portion 48
It is rotated and stirred by the adhesive force of 2. Therefore, according to the present embodiment, the chargeability of the toner is improved by the agitation due to the adhesive force, the fog can be prevented, and the reproducibility of fine lines can be improved.

Further, in the present embodiment, by forming the tip portion 482 using a material having a high tack value, it is possible to reduce the contact pressure of the regulating blade 48 against the developing roller 47 and to prevent fog. can do. Therefore, according to the present embodiment, the regulating blade 48 is brought into contact with the developing roller 47 with a relatively low contact pressure, whereby the developing roller 47 and the regulating blade 48 are contacted.
Can be reduced, toner deterioration can be prevented, and toner sticking to the developing roller 47 can be prevented, so that the life of the apparatus can be extended. Further, by reducing the contact pressure of the regulating blade 48 against the developing roller 47, the tip portion 482 and the developing roller 47
Is reduced between the developing roller 4 and the developing roller 4.
7 can be suppressed.

In the above-described method of measuring the tack value, from the viewpoint of observing the relationship between the adhesive force between the toner and the chip portion forming material, a toner probe formed by pressing the toner into a pellet is used. Although the case has been described, other probes may be used for convenience.
For example, instead of the toner probe, the tack value may be measured using a standard SUS probe (diameter: 5 mm) (hereinafter referred to as a “SUS probe”).
Table 2 below shows the measurement results when a US probe was used.

[0035]

[Table 2] As is apparent from Table 2, even when the SUS probe is used instead of the toner probe, the tack values of the samples 1 to 4 (hereinafter, referred to as “preliminary tack values”).
Indicates the same tendency as in Table 1 (Sample 1> Sample 2> Sample 3> Sample 4). Therefore, in the present invention, if necessary, a preliminary tack value is measured using a SUS probe or the like, and a correlation between the tack value obtained by the toner probe and the preliminary tack value is found, and this correlation is determined. After finding it, the tack value at the time of material selection may be used based on the preliminary tack value and the correlation obtained for each sample. As described above, the tack value used as the index for selecting the material of the chip portion in the present invention can be obtained by using a standard probe (such as SUS) without using a toner probe or the like. Can be inferred, and after finding the above correlation, it is possible to easily select a chip part material using a SUS probe or the like. If a SUS probe or the like can be used in this way, the handling of the probe is easier than in the case of using a toner probe that is liable to be damaged, so that the tack value can be measured in a short time. The material of the probe is not limited to stainless steel, but may be other metals, resins, ceramics, or the like.

Further, in the present embodiment, the circularity is set to 0.
Using 98 toners, the evaluation of “fog” of the chip portion formed by each sample is performed. Such a toner having a high degree of circularity generally has a high fluidity and a high slipperiness, and thus may be able to slip through the regulating blade. When such rub-through occurs, the rub-through toner is not preferable because it causes fogging or the like during image formation. However, in the present embodiment, as is clear from Tables 1 and 2, even when a toner having a high circularity is used, by forming the chip portion with a material having a large tack value, Scratch-through can be prevented, and the toner can be charged with sufficient stirring and the like to reduce fog, thereby improving image quality. Therefore, according to the present embodiment, it is possible to obtain a developing device suitable for using a toner having a high circularity.

In this embodiment, the chip portion 4
Reference numeral 82 is in contact with the developing roller 47 in a belly state. That is, since the position distant from the vicinity of the edge of the tip portion 482 is in contact with the developing roller 47, the tip portion 4
The chip portion 482 and the developing roller 47 can be stably contacted without being affected by edge burrs or straightness at the time of forming the 82. In the case where the abutting is performed in such a manner, the toner is generally likely to be excessively conveyed. However, in the present embodiment, the tip portion 482 is formed of a material having a relatively high tack value. Therefore, the toner is not excessively conveyed even if the toner is abutted in the abdomen contact state, and the developing roller 47 can obtain an appropriate conveyance amount.

The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, in the above embodiment, the present invention is applied to a rotary developing device, but the application of the present invention is not limited to this, and the developing devices 4K, 4C, 4M, and 4Y are independently provided. Also in this case, by applying the present invention to each developing device, the same operation and effect as the above embodiment can be obtained.

In the above embodiment, the present invention is applied to a developing device provided in an image forming apparatus capable of forming a color image using four color toners. The object is not limited to this, and can be naturally applied to a monochrome-only developing device provided in an image forming apparatus that forms only a monochrome image.

In the above embodiment, the regulating blade is in contact with the developing roller in a belly-contact state, and the contact pressure is 294.20 mN / cm (30 gf).
/ Cm), but the present invention is not limited to this, and the contact pressure is, for example, 147./cm).
10 mN / cm (15 gf / cm) to 539.37 mN
/ Cm (55 gf / cm). However,
Needless to say, when changing the contact pressure,
The tip portion should be formed using a material having a tack value corresponding to the contact pressure.

Further, in the above embodiment, the case where the regulating blade is arranged in the counter state has been described. However, the present invention is not limited to this configuration, and the regulating blade has a relatively low contact pressure (147. 10-53
(At about 9.37 mN / cm), the mounting state of the regulating blade is not limited to any state. Therefore, for example, the regulating blade may be arranged in a trail state.

[0042]

As described above, according to the present invention, the material for forming the tip portion is easily selected by using the tack value as an index (the material having a large tack value), and the regulating blade having the tip portion is developed. The developing device is configured to contact the roller. Therefore, according to the present invention, since the adhesive force between the chip portion and the toner is increased, the toner is rotated and stirred on the surface of the chip portion, and the chargeability of the toner is improved. As a result, fog is prevented and fine line reproducibility is improved, so that a developing device capable of improving image quality can be obtained. Further, according to the present invention, by forming the tip portion with a material having a large tack value, it is possible to achieve both a reduction in the contact pressure of the regulating blade against the developing roller and prevention of fog. Therefore, the regulating blade is brought into contact with the developing roller at a relatively low contact pressure to reduce stress generated between the developing roller and the regulating blade, thereby preventing toner deterioration and preventing toner from sticking to the developing roller. And a longer life of the device can be realized. Further, by reducing the contact pressure of the regulating blade against the developing roller, the frictional force generated between the chip portion and the developing roller is reduced, so that the driving torque of the developing roller can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an image forming apparatus equipped with an embodiment of a developing device according to the present invention.

FIG. 2 is a view showing a rotary developing unit as an embodiment of the developing device according to the present invention.

FIG. 3 is a partially enlarged view of the developing device of FIG. 2;

FIG. 4 is a diagram for explaining a method of measuring a tack value according to the present invention.

[Explanation of symbols]

 2. Photoconductor (image carrier) 47: Developing roller (toner carrier) 48: Regulator blade (regulator) 482: Tip (contact portion) DP: Development position EP: Contact position T: Toner

Claims (1)

[Claims] An image forming apparatus includes: a toner carrier that conveys toner to a development position facing an image carrier by rotating while carrying toner; and a toner carrier that abuts on the toner carrier to transfer the toner to the toner carrier. Regulating means for regulating the transport amount and forming a charged toner thin layer on the surface of the toner carrier, wherein a contact portion of the regulating means contacting the toner carrier,
A developing device characterized in that the developing device is formed using a material having a tack value indicating an adhesive force to a toner of 750 mN or more and 1500 mN or less.