JP2003066722A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of parts while suppressing the generation of a developing history. SOLUTION: This image forming device is provided with a photoreceptor 1 having an electrostatic latent image formed thereon, a development roller 2 which feeds toner T for a toner image to this photoreceptor 1 and develops the electrostatic latent image on the photoreceptor 1, a feeding roller 3 for feeding the toner T to this development roller 2, and a recovery blade 4 of which the tip part abuts on the development roller 2 and recovers the toner T remaining and stuck to the development roller 2. The recovery blade 4 is formed of an elastic member and arranged so that the tip of the recovery blade 4 is opposite to the turning direction of the development roller 2. An angle formed by a tangent at the contacting place with the recovery blade 4 of the development roller 2 and the neighborhood of the tip of the recovery blade 4 is within a range from 10 deg. to 36 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a collecting blade for collecting residual toner from a developing roller.

[0002]

2. Description of the Related Art Conventionally, there is known an image forming apparatus of a non-magnetic one-component developing system such as a laser printer which transfers a toner image formed on a photoconductor to a predetermined paper by using the photoconductor. FIG. 4 shows the configuration of a general image forming apparatus.

The general image forming apparatus shown in FIG.
An image holding member including a photosensitive member 101 such as C (organic optical semiconductor), a developer carrying member such as a developing roller 102, a developer supplying member including a supplying member such as a supplying roller 103, and a regulating blade 104. ing. Further, although not shown, the image forming apparatus includes a charger for charging the surface of the photoconductor, a charge eliminator for removing the electric charge charged on the surface of the photoconductor, and the like. Then, the photosensitive portion is formed by these members.

The photosensitive portion thus constructed charges the surface of the photosensitive member by discharging the charger and scans the surface of the photosensitive member 101 with laser light from the print head to form a latent image. Next, the toner adsorbed on the surface of the developing roller 102 by an electric force or a magnetic force is adsorbed on the latent image by Coulomb force to form a latent image toner. This latent image toner is transferred to a sheet and fixed on the sheet. Then, in order to prepare for the next charging, the photoconductor 10 is removed by a static eliminator.
By removing the electric charge charged on the surface of the photosensitive member 1,
The surface of 01 is returned to the initial state. Then, by repeating the above process, a desired printed matter can be obtained.

However, in the image forming apparatus having such a structure, for example, in the case of a character image having a small print area ratio, the image is not formed on the developing roller after development (after passing through the photosensitive member and the developing roller facing portion). Most of the developer (toner) remains, and these toners are scraped off by the supply roller and adhere to the supply roller. The reason why the toner adheres to the supply roller is that the toner is charged.

When the charged toner adhering to the supply roller is supplied again to the developing roller, the developing roller is conductive and the developer is strongly attracted. As a result, in the case of an image such as a character image that consumes a small amount of toner, the amount of toner passing through the regulation blade tends to increase. Therefore, there arises a problem that a development history is generated on the printed matter.

On the other hand, when a solid image having a large printing area is printed, almost no toner remains on the developing roller after development. Therefore, at this time, since the toner supplied from the supply roller to the developing roller is the toner supplied from the toner hopper, that is, the toner is not charged,
The adhesive force to the developing roller due to the image force is small, so that the amount of toner passing through the regulation blade is small. As a result, after the solid image is printed, there is a shortage of toner supplied to the position corresponding to that portion, which causes a problem that a development history called negative ghost occurs in which the image density decreases.

In order to avoid this problem, Japanese Patent Laid-Open No. 9-2
There is a method disclosed in Japanese Patent No. 74383. Figure 5
Will be explained. In the image forming apparatus disclosed in Japanese Patent Laid-Open No. 9-274383, the photoconductor 201, the developing roller 202, the supply roller 203, and the regulating blade 20 are similar to the above.
4. Other components included in a general image forming apparatus are provided. The image forming apparatus further includes a collecting blade 205 for removing the toner 206 remaining on the surface of the photoconductor 201. Looking at the recovery blade 205 from the rotation direction of the developing roller 202,
It is provided on the upstream side with respect to the supply roller 203. By doing so, the toner remaining on the developing roller 202 after development can be removed, and the developing roller 202 can be in the initial state immediately before the toner 206 is newly supplied by the supply roller 203. it can. As a result, since a constant amount of toner can be constantly supplied to the developing roller 202 without being affected by the immediately preceding developing state, development history is suppressed. The recovery blade 205 at this time is formed of a film member so as not to damage the developing roller 202 and the like.

[0009]

However, since the recovery blade, which is a film member, is weak in strength, the toner on the developing roller may not be scraped off even when the tip of the collecting blade is brought into contact with the developing roller. On the other hand, even if the film member is a film member, depending on the contact angle, pitch unevenness may occur, or the developing roller may be scraped or scratched.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of improving the disadvantages of the above-mentioned conventional examples, and in particular, suppressing the occurrence of development history and prolonging the life of parts. And

[0011]

Therefore, in the present invention, a photosensitive member on which an electrostatic latent image is formed, and a toner for supplying a toner image to the photosensitive member are supplied to the electrostatic latent image on the photosensitive member. A developing roller for developing the toner, a supply roller for supplying the toner to the developing roller, and a collecting blade for collecting the toner remaining on the developing roller by abutting the tip of the developing roller. , Which is made of an elastic member, and is arranged such that the tip of the collecting blade faces the rotation direction of the developing roller, and the tangent line of the developing roller in contact with the collecting blade and the vicinity of the tip of the collecting blade. The angle formed by and is within the range of 10 ° to 45 °. At this time,
Particularly, the angle formed by the tangent line at the contact point of the developing roller with the collecting blade and the vicinity of the tip of the collecting blade is 10 °.
It is desirable that the angle is within a range of from 36 ° (claim 2). With such a configuration, the electrostatic latent image formed on the photoconductor is developed with the toner supplied by the supply roller and the developing roller, and the toner image is transferred onto a predetermined sheet. After the development, the toner remaining on the developing roller is effectively scraped off by the collecting blade, and the developing roller is initialized. Therefore, it is possible to suppress the development history from occurring in the printed matter. Particularly, when the recovery blade made of an elastic body is arranged at a predetermined angle, it comes into contact with the developing roller with a predetermined strength, so that the toner can be effectively scraped from the developing roller. At the same time, damage to the developing roller can be suppressed.

Further, it is desirable that the free length of the recovery blade is 5 mm to 15 mm (claim 3). Even in this case, the recovery blade comes into contact with the developing roller with a predetermined strength, so that the toner can be effectively scraped from the developing roller, and damage to the developing roller is suppressed. You can Further, since the recovery blade has a predetermined length, even if the recovery blade is scraped off, the toner scraping effect is prevented from decreasing.

Further, recovery toner supply means for supplying the toner collected from the developing roller by the recovery blade to the supply roller may be provided so that the toner is supplied from the supply roller to the developing roller (claim 4). . It is desirable that a toner holding unit that holds a predetermined amount of toner is provided above the supply roller (Claim 5). As a result, since the toner collected from the developing roller is charged, the charged toner is again supplied to the developing roller via the supply roller, thereby suppressing a decrease in the amount of toner adhered to the developing roller. It is possible to obtain a printed matter having a stable printing density. Further, since the toner supplied from the supply roller to the developing roller is always held on the supply roller, stable toner supply can be achieved,
It is possible to obtain a printed matter with a more stable printing density.

Further, it is desirable that the developing roller and the supply roller are disposed in non-contact with each other (claim 6). At this time, it is still more desirable to provide a voltage applying means between the developing roller and the supply roller, which has the same polarity as the charging polarity of the toner and applies a voltage so that the potential difference becomes 50 V to 1000 V (claim 7). As a result, due to the action of the electric field generated between the developing roller and the supply roller, the charged toner is attracted from the supply roller to the developing roller, the toner can be efficiently supplied, and a printed matter with good image quality can be obtained. Further, it is possible to suppress damage to both the developing roller and the supply roller due to contact with each other. In such a case, the residual toner on the developing roller cannot be collected by the supply roller, but is collected by the collecting blade as described above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to FIGS. FIG. 1 is a sectional view showing the arrangement of an image forming apparatus according to the present invention. FIG. 2 is an explanatory diagram showing the positional relationship between the recovery blade and the developing roller. FIG. 3 is a diagram showing characteristics at the time of printing due to a change in the positional relationship between the collecting blade and the developing blade.

The image forming apparatus of the present invention is an electrophotographic printer that outputs a monochrome image. However,
The electrophotographic printer is not limited to a monochrome printer, and may be a multicolor (color) electrophotographic printer.

(Overall Structure) As shown in FIG. 1, an image forming apparatus includes a photoconductor 1 on which an electrostatic latent image is formed, and a toner T supplied to the photoconductor 1 for a toner image. 1, a developing roller 2 for developing an electrostatic latent image, a supplying roller 3 for supplying the toner T to the developing roller 2, and a tip end portion of the developing roller 2 abutting on the developing roller 2 and remaining attached to the developing roller 2. And a collecting blade 4 for collecting the toner T present. The image forming apparatus also includes a toner holding unit 5 that holds a predetermined amount of toner T on the supply roller 3, a regulation blade 6 that regulates the amount of toner supplied from the supply roller 3 to the developing roller 2, and a toner. The return seal 7 is provided to prevent T from leaking outside the device.

The toner T is stored in the toner storage case 8, and the toner hopper 81 in which the toner T supplied to the supply roller 3 temporarily stays therein.
Are formed. Further, the first paddle 9A that scrapes the toner T remaining in the toner hopper 81 from the supply roller 2 and the second paddle 9B that scrapes the toner T collected by the collecting blade 4 into the toner hopper 81 are the main image. It is provided in the forming device.

(Principle of Operation) With such a configuration, the operation basically is as follows. First, an electrostatic latent image is formed on the photoconductor 1 such as OPC by a general method by an exposure unit (not shown). On the other hand, the toner T is supplied to the developing roller 2 by the supply roller 3. At this time, the toner T contacts the developing roller 2 or the regulating blade 6 by the regulating blade 6 and is triboelectrically charged, and a thin layer of the toner T having a constant thickness is formed on the developing roller 2. continue,
The toner T on the developing roller 2 comes into contact with the electrostatic latent image on the photoconductor 1 or is conveyed in the vicinity thereof, and the OPC 1 and the developing roller 2
The latent image on the OPC 1 is developed at the facing portion of.

After that, the toner image developed on the photosensitive member 1 is transferred onto a sheet conveyed while being in contact with the photosensitive member 1 by a conveying roller (not shown) as a sheet feeding means. Then, the toner T remaining on the surface of the photoconductor 1 after the transfer is removed by the collecting blade 4, and the toner image transferred on the sheet is fixed to the sheet by being pressurized and overheated by a fixing unit (not shown). Hereinafter, this will be described in detail.

(Constituent Elements) The photoreceptor 1, the developing roller 2, and the supply roller 3 are substantially the same as those provided in an image forming apparatus such as a general laser printer, and therefore their explanations are omitted. Here, OPC (organic optical semiconductor)
The photosensitive member 1 and the developing roller 2 are provided at a predetermined interval or in contact with each other. Similarly, the developing roller 2 and the supply roller 3 are arranged close to each other (at a predetermined interval) or in contact with each other. However,
In the present embodiment, the developing roller 2 and the supply roller 3 are in a state of being close to each other without making contact with each other. As a result, it is possible to suppress damage due to the contact between the rollers. At this time, if the toner T remaining on the developing roller 2 cannot be removed by the supply roller 3 unless they are brought into contact with each other, the collecting blade 4 will be described later.
Will play that role, so there is no problem. It should be noted that these components are provided in the image forming apparatus main body or the toner containing case 8 containing the toner T. The components described below are also the same.

(Regulation Blade) Here, a regulation blade 6 is disposed on the rotation direction side of the developing roller 2 with respect to the vicinity of the developing roller 2 and the supply roller 3, that is, on the upper side in FIG. The regulation blade 6 is arranged at a predetermined distance from the developing roller 2, and charges the toner T or controls the amount of the toner T supplied from the supply roller 3 to the developing roller 2 as described above. Play a limiting role. As a result, the toner T having a constant thickness is formed on the developing roller 2.
Thin film is formed.

(Toner Holding Means) Further, a toner holding means 5 having a substantially plate shape is provided adjacent to the supply roller 3 (on the right side in FIG. 1) to form a wall. The toner holding means 5 is
Since it is provided on the side opposite to the developing roller 2, the supply roller 3 is sandwiched between the toner holding means 5 and the developing roller 2. And thereby, the developing roller 2
A predetermined amount of toner T supplied to the developing roller 2 by the supply roller 3 is always held above the supply roller 3 surrounded by the toner holding means 5.
The toner T is supplied to the upper part of the supply roller 3 by a first paddle 9A described later.

(Recovery Blade) Photosensitive Member 1 of Developing Roller 2
A return seal 7 and a recovery blade 4 are disposed on the downstream side of the contact portion with or near the contact portion. The recovery blade 4 is arranged via a recovery blade support member 41 provided in the toner storage case 8. The recovery blade 4 is formed of a PET film having a thickness of 100 μm. The shape is a plate shape (sheet shape) having a width substantially the same as the width of the developing roller 2.
Then, the recovery blade supporting member 41 described above is in a state of protruding by a predetermined length. The free length that is the protruding portion will be described later.

Here, the collecting blade 4 and the developing roller 2
Consider the positional relationship with. That is, as shown in FIG. 2, the recovery blade 4 is even arranged so that its tip portion abuts on the developing roller 2. However, the tangent line of the developing roller 2 at the contact point and the tip of the recovery blade 4 are arranged. The angle θ formed by the section will be examined. Here, θ is the rotation direction side (downstream) of the developing roller 2 when the collecting blade 4 is arranged so that its tip end faces the rotation direction of the developing roller 2, as shown in FIG. Side).

In FIG. 3, an angle θ between the tangent line of the contact portion of the developing roller 2 and the tip of the recovery blade 4 is a predetermined angle (°).
(0 to less than 10; 10 to less than 36; 36 to less than 45; 4
The degree of development history, the scraping effect of the toner T by the collecting blade 4, the uneven pitch, the scraping of the developing roller 2, and the scraping of the collecting blade 4 were examined.

Then, by disposing the collecting blade so that θ becomes 10 to less than 45 °, the developing roller 2
The toner T above could be scraped off by almost 90% or more. It was also found that when the tip angle θ is smaller than 10 °, the toner T on the developing roller 2 is scarcely scraped off. As a result, a development history was generated. When the angle θ is 45 ° or more, the recovery blade 4 is initially used.
However, in the printing durability test, the tip of the collecting blade 4 moved in the rotation direction of the developing toner 2 and the angle θ became 90 ° or more, and a stable scraping effect was not obtained. The development history appears. The angle θ of the recovery blade is 4
In the case of 5 to 70 °, uneven pitch appears in the printed image,
When it was 70 or more, the scraping effect was not obtained, and the development history was generated. When the recovery blade angle is 36 to 45 °, a flaw may occur in the central portion of the developing roller,
It was found that the scraping of the recovery blade was also large. this is,
The recovery blade 4 is a member having elasticity, which is a PET film in this experiment, but the strength becomes weak with such a member, and there are cases in which the toner scraping effect cannot be expected. However, when the recovery blade 4 is brought into contact with the developing roller 2 at a predetermined angle, the strength of the recovery blade 4 is increased and a scraping effect is generated.

From the above experimental results, the recovery blade 4
It is found that the optimum contact angle θ with respect to the developing roller 2 is 10 to less than 36 °. If the recovery blade 4 is expected to scrape off the residual toner so as to suppress the occurrence of the development history, it is 45 even at 36 ° or more.
It may be less than °.

Next, the length of the recovery blade 4 will be examined. Here, the length means the length of the recovery blade 4 protruding from the recovery blade supporting member 41 on which the recovery blade 4 is supported, that is, the free length of the recovery blade 4. The free length of the recovery blade 4 is 5 to 1
5 mm is desirable. This is because if it is less than 5 mm, the scraping effect is reduced when the recovery blade 4 is scraped due to printing durability, and if it is 15 mm or more, the scraping effect is reduced and uneven pitch is likely to occur. When the free length was set to 10.5 to 13.5 mm and the angle θ was set to 20 °, a stable image having no development history was formed in the printing durability test of 12,000 sheets.

(Paddle) Here, the toner T scraped off by the collecting blade 4 collects in a predetermined portion of the toner containing case 8, and a second paddle 9B is arranged at such a portion. The second paddle 9B is composed of a rotary blade and a drive means (motor or the like) for rotationally driving the rotary blade. As the blade rotates, the toner T accumulated at that location is removed from the toner hopper. It is conveyed to the 81 side. Then, the first paddle 9 is provided above the toner hopper 81.
A is provided and the blades of the paddle rotate, so that the toner T in the toner hopper 81 is mixed and conveyed to the upper portion of the supply roller 3.

At this time, the toner T scraped off is the second
The toner T remains charged in the area where the paddle 9B is disposed, but the toner T is charged. Then, by the rotation of the second paddle 9B, the toner is conveyed to the toner hopper 81 portion. Here, the uncharged toner T originally present in the toner hopper 81 portion is mixed by the rotation of the first paddle 9A. Therefore, the toner T in the toner hopper 81 is in an appropriately charged state, and the toner T is supplied to the developing roller 2 via the supply roller 3. Therefore, since the charged state of the toner T supplied to the developing roller 2 is always uniform, the developing state is uniform and the printed matter can be uniform.

Further, part of the toner T conveyed by the first paddle 9A falls on the supply roller 3 and the rest falls on the hopper. At this time, since the amount of the toner T on the supply roller 3 is made constant by adjusting the height of the toner holding means, the amount of toner supplied from the supply roller 3 to the developing roller 2 is made uniform. Therefore, the print density of the printed matter can be made uniform.

Here, as described above, the recovery blade 4
In the above, the case where it is formed of a PET film having a thickness of 100 μm is illustrated, but the invention is not necessarily limited to this. In addition to this, a PET film having a thickness of 75 to 200 μm, 60 to 18
A dielectric film such as a polycarbonate film or a polyimide film having a thickness of 5 μm may be used. Even if such a film was used, the same effect as described above was obtained. Also, the thickness 50
Even with a recovery blade made of metal such as SUS having a thickness of μm or less, the same effect as described above was obtained.

By doing so, the developing roller 2
The residual toner T can be effectively scraped off, and the development history can be suppressed. Specifically, in the conventional case,
There is a difference in the amount of adhesion between white solid printing and black solid printing,
Although the developing roller ghost has occurred, since the image is not affected in the configuration of the present invention, a stable toner thin layer can be always formed on the developing roller 2 and the occurrence of the developing roller ghost can be suppressed. In other words, since the toner T having a constant amount and a constant charge amount can be conveyed by the developing roller 2 regardless of the image, it is not affected by the image printed immediately before, that is, the development history can be suppressed.

Further, conventionally, in order to make the toner adhesion amount to the developing roller 2 constant regardless of the image, it was necessary to increase the linear pressure of the regulating blade 6 to the developing roller 2.
In the present embodiment, since the toner adhesion amount to the developing roller 2 is made uniform as described above, it is not necessary to increase the linear pressure, and the conventional linear pressure of 4 to 20 gf / mm is 2 gf / m.
It can be reduced to m or less.

When a dielectric film such as PET, PC or polyamide is applied in place of the metal regulation blade 6 such as SUS in the conventional constitution (the constitution without the recovery blade), the regulation blade 6 is used. Linear pressure 1gf
However, the amount of developer adhering to the developing roller 2 was 2 mg / cm ² or more, and fog occurred. However, in the configuration of the present invention, a PET film having a Nitoflon tape attached to the tip is applied to the blade so that the adhesion amount can be 0.9 mg / cm ² or less, and an image with reduced fog can be obtained. I was able to.

Further, since the linear pressure of the regulation blade 6 can be reduced, it is possible to construct an image forming apparatus which does not adhere to the regulation blade 6 even when a low melting point color toner is used.

Further, since the conventional supply roller 3 also has the effect of removing the reverse image remaining on the developing roller 2,
There is a problem that the developing roller 2 is strongly pressed against the developing roller 2 and as a result, the developing roller 2 is scraped off, and the life of the apparatus cannot be extended, and a torque becomes extremely large, which increases the strength of the component parts, resulting in high cost. there were. However, the supply roller 3 need only be capable of sufficiently supplying the toner T, and therefore the supply roller 3 does not need to be strongly pressed against the developing roller 2. Therefore, the supply roller 3
The rotation torque can be reduced, and the life and cost of the device can be greatly improved.

Further, as described above, since the collecting blade 4 plays a role of removing the residual toner, it is not necessary to scrape off the toner by the supply roller 3, so that the supply roller 3 and the developing roller 2 have a small gap. Alternatively, since the contact of the supply roller 3 with respect to the developing roller 2 is smaller than in the conventional case, or the supply roller 3 is relatively soft and can be contacted and rotated,
The amount of abrasion of the developing roller 2 by the supply roller 3 becomes extremely small, and the durability can be improved.

At this time, for example, when the supply roller 3 and the developing roller 2 are arranged with a small gap of 30 μm to 300 μm, the supply toner 3 to the developing roller 2 are provided.
Inconvenience that the toner T is not sufficiently supplied to the toner may occur. In such a case, negatively charged toner is used, and between the supply roller 3 and the developing roller 2 is −50 V to −1000 V, preferably −500 V to −800 V.
It is recommended to apply the potential of. Specifically, electrodes are connected to the supply roller 3 and the developing roller 2, and a voltage supply means (not shown) having a power supply for applying the above voltage is provided between the electrodes. As a result, the toner T is supplied to the developing roller 2. This is because the charged toner is supplied to the supply roller 3 by the action of the electric field generated by the applied potential.
This is because the toner is attracted to the developing roller 2 side. Here, even if a potential of +50 V to +1000 V, preferably +500 V to +800 V is applied between the supply roller 3 and the developing roller 2 using the positively charged toner, the toner T is applied to the developing roller 2 in the same manner as above. Will be supplied.

However, when the voltage supply means is provided as described above, it is not limited to the case where there is a minute gap between the supply roller 3 and the developing roller 2. Even when the supply roller 3 and the developing roller 2 are in contact with each other, the voltage supply means may be provided. Even in such a case, the developing roller 3 can effectively supply the toner T.

[0042]

Since the present invention is constructed and functions as described above, according to this, by setting the contact angle of the collecting blade to the developing roller to a predetermined angle (10 ° to 45 °),
Since the residual toner on the developing roller can be effectively scraped off, the occurrence of development history can be suppressed and a good printed matter can be obtained. Further, particularly when the contact angle between the collecting blade and the developing roller is set to 10 ° to 36 °, damage (scraping) of the developing roller and the collecting blade can be suppressed, and the life of the apparatus is prolonged and the number of printed sheets It has an unprecedented excellent effect that it is possible to suppress the deterioration of the printing state due to the increase of

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration in an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship between a recovery blade and a developing roller disclosed in FIG.

FIG. 3 is a diagram showing characteristics at the time of printing due to a change in the positional relationship between the recovery blade and the developing blade disclosed in FIG.

FIG. 4 is a sectional view of a general image forming apparatus in a conventional example.

FIG. 5 is a sectional view of a general image forming apparatus in a conventional example.

[Explanation of symbols]

1 photoconductor 2 developing roller 3 supply rollers 4 Recovery blade 5 Toner holding means 6 regulation blade 7 Return seal 8 Toner storage case 81 Toner Hopper 9A first paddle 9B Second paddle T toner

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Jun Oyazu             5-7 Shiba 5-1, Minato-ku, Tokyo NEC Corporation             Inside the company F-term (reference) 2H077 AB03 AB15 AC03 AC04 AC13                       AC16 AD06 AD13 AD32 BA08                       DB25 GA03

Claims (7)

[Claims] 1. A photoconductor on which an electrostatic latent image is formed, a developing roller for supplying toner for a toner image to the photoconductor to develop the electrostatic latent image on the photoconductor, and the developing roller. A developing roller is provided with a supply roller for supplying toner to the roller, and a recovery blade for contacting the developing roller with its tip end to recover the toner remaining on the developing roller. In the image forming apparatus for transferring the formed toner image, the collecting blade is formed of an elastic member, and the tip of the collecting blade is disposed so as to face in the rotation direction of the developing roller, The angle formed by the tangent line at the contact point of the roller with the recovery blade and the vicinity of the tip of the recovery blade,
An image forming apparatus having a range of 10 ° to 45 °. 2. The angle between the tangent line of the developing roller at the contact point with the collecting blade and the vicinity of the tip of the collecting blade is in the range of 10 ° to 36 °. 1. The image forming apparatus according to 1. 3. The image forming apparatus according to claim 1, wherein the recovery blade has a free length of 5 mm to 15 mm. 4. A recovery toner supply means for supplying the toner to the supply roller so that the toner recovered from the development roller by the recovery blade is supplied from the supply roller to the development roller. The image forming apparatus according to claim 1, 2, or 3. 5. The image forming apparatus according to claim 1, 2, 3, or 4, wherein a toner holding unit that holds a predetermined amount of the toner is provided above the supply roller. 6. The developing roller and the supply roller,
It is arranged in a non-contact manner.
4. The image forming apparatus according to 4 or 5. 7. The same polarity as the charging polarity of the toner and a potential difference of 5 between the developing roller and the supply roller.
6. The image forming apparatus according to claim 1, further comprising a voltage applying unit that applies a voltage from 0V to 1000V.