JP2009282193A - Developing device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which is superior in the circularity of toner around a layer thickness regulation member, and to provide an image forming apparatus having the developing device. <P>SOLUTION: The developing device 7 comprises: the layer thickness regulation member 76 for forming a developing roller 72 and a toner thin layer; a toner supply roller 73 for supplying the toner to the developing roller 72; and a toner stirring member 74 for circulating the toner in a toner housing part 71, wherein the toner stirring member 74 is disposed at a part which is lower than the extension line of a tip part 76b on the tip side from a fold part 76a of the layer thickness regulating member 76 and the shortest distance between the circumferential line of the tip of the toner stirring member 74 and the extension line is defined as being ≤5 mm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus used for a copying machine, a printer, a FAX, and the like.

Conventionally, a one-component developing device has been widely used as one of developing devices used in an electrophotographic image forming apparatus. The developing device used for this has a horizontal structure that is installed horizontally with respect to the image carrier, transports the developer in the horizontal direction from the hopper chamber in the developing device, and supplies the developer to the developer carrier. There are many things. Generally, this horizontal type developing device has a good dispersibility and a good image uniformity because the developer moving direction is different from the gravity direction.
In the case of an image forming apparatus that forms a color image by synthesizing 3 to 4 color images, it is necessary to arrange 3 to 4 developing units including a latent image carrier, and the entire apparatus is made compact and developed. In order to secure the capacity of the agent, it is preferable to arrange the developing units horizontally rather than vertically. Further, in order to arrange the developing units horizontally and make the entire image forming apparatus compact, it is necessary to adopt a so-called vertical structure in which the hopper is arranged above the developing unit.

However, when developing using such a vertical developing device as a one-component developing device, the developer is supplied onto the developer carrying member due to the remaining amount of the developer, the tightening of the developer due to standing, and the rotation of the stirring member. The pressure applied to the restricting member that restricts the developer to a predetermined amount fluctuates, causing density changes and image unevenness in the developed image.
For this reason, in the developing device having a vertical structure, a hopper unit and a developing unit are divided so that the developer pressure applied to the regulating member does not change, and a device for supplying the developer from the hopper unit to the developing unit is provided, When the developer sensor is provided in the developing unit and the developer in the developing unit is reduced, a means for supplying the developer from the hopper is necessary, which causes an increase in cost.

  In view of the above problems, as a conventional technique in which the development apparatus has been improved, for example, a retention preventing material that prevents the toner core from retaining on the upstream side of the pressure contact portion with the developer layer thickness regulating member is provided. A one-component developing device is disclosed in which the layer thickness regulating member is a rigid member whose nip width with the developing roller is in point contact with the rotation direction of the developing roller (see, for example, Patent Document 1). In the one-component developing device, the circulation of the toner around the layer thickness regulating member for forming the toner thin layer is very important. The reason why toner circulation is necessary is that the toner circulation property is poor, and if the toner stays at the tip of the regulating member, the additive on the toner surface is buried / dropped by the pressure of the regulating member, and the chargeability of the toner is reduced. descend. Moreover, it becomes a cause of sticking to a control member by the influence of the heat_generation | fever in a braid | blade. Alternatively, the toner adheres on the developer carrying member, and a phenomenon of toner conveyance amount decrease and charge property decrease occurs. Then, the fixing of the toner to the regulating member causes white streaks, the reduction of the toner conveyance amount causes the reduction of the image density, and the reduction of the chargeability generates an abnormal image such as a background stain (fogging).

JP 2007-79322 A

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device having good toner circulation around the layer thickness regulating member and an image forming apparatus including the developing device. And

The features of the present invention, which is a means for solving the above problems, are listed below.
A developing device according to the present invention includes a layer thickness regulating member for forming a developer carrier and a toner thin layer, a toner replenishing member for supplying toner to the developer carrier, and a toner for circulating toner in a toner container. In the developing device having a toner stirring member, the toner stirring member is provided below the extension line of the tip portion on the tip side of the bent portion of the layer thickness regulating member, and the periphery of the tip of the toner stirring member is provided. The shortest distance between the line and the extension line is 5 mm or less.
Further, the developing device of the present invention is the developing device described above, wherein a linear speed ratio (stirring linear speed / replenishment linear speed) of the toner stirring member and a toner supply member is 1.5 or more. It is characterized by.
The developing device of the present invention is further characterized in that, in the developing device described above, the bending angle of the tip of the layer thickness regulating member is 90 ° or less.
Further, the developing device of the present invention is the developing device according to any one of the above, wherein the volume average particle size (Dv) is 3 to 8 μm, the volume average particle size (Dv) and the number average particle size (Dn). A toner having a ratio (Dv / Dn) of 1.00 to 1.40 is used.

Further, the developing device of the present invention is the toner according to any one of the above-described developing devices, wherein the shape factor SF-1 is in the range of 100 to 180 and the shape factor SF-2 is in the range of 100 to 180. Is used.
Further, the developing device of the present invention further includes a polyester prepolymer having a functional group containing at least a nitrogen atom, a polyester, a colorant, and a release agent dispersed in an organic solvent. It is a developer obtained by subjecting the toner material liquid to a crosslinking reaction and / or elongation reaction in an aqueous medium.
A process cartridge according to the present invention includes any one of the developing devices described above.
An image forming apparatus according to the present invention includes any one of the developing devices described above.
A process cartridge according to the present invention includes the process cartridge described above.

  In the developing device and the image forming apparatus including the developing device as means for solving the above problem, the toner circulation property around the layer thickness regulating member is good.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

FIG. 1 shows an embodiment of an image forming apparatus of the present invention. In the image forming apparatus main body, yellow (Y), magenta (M), cyan (C), and black (K) image carriers (also referred to as photoconductors) 1Y, M, C, and K are arranged in parallel. It is arranged. That is, this image forming apparatus is a tandem type color laser copying machine. The image forming apparatus main body includes a printer unit 100 and a paper feeding device 200 on which the printer unit 100 is placed. The pressure plate open / close scanner includes a scanner unit main body 300 fixed on the printer unit 100 and an automatic document feeder 400 rotatably provided on the scanner unit main body 300.
The printer unit 100 forms an image including four process cartridges 18Y, 18M, 18C, and 18K for forming an image of each color of yellow (Y), magenta (M), cyan (C), and black (K). A unit 20 is provided. Y, M, C, and K added after the numbers of the respective symbols indicate members for yellow, magenta, cyan, and black. In addition to the process cartridges 18Y, 18M, 18C, and 18K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 22, a belt fixing type fixing device 25, and the like are disposed.

  When copying a document, the user sets, for example, a bundle of sheet documents on the document table 30 of the automatic document feeder 400. Alternatively, one original is placed on the contact glass 32. When placing the sheets one by one on the contact glass 32, first, the automatic document feeder 400 is rotated upward with respect to the scanner unit main body 300 to expose the contact glass 32. Thereafter, the document is placed on the contact glass 32, and then the automatic document feeder 400 is rotated downward to sandwich the document with the contact glass 32.

When the copy start switch is pressed after the document is set in this way, the document reading operation by the scanner unit main body 300 starts. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 operates to move the sheet document to the contact glass 32 prior to this document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 start traveling together, and light is emitted from a light source provided in the first traveling body 33. The reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, then passes through the imaging lens 35, and finally enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light. When the sheet document is placed on the contact glass 32 by the automatic document feeder 400, the sheet document is discharged to the document discharge unit 31.
In parallel with such document reading operation, each device in each of the process cartridges 18Y, 18M, 18C, 18K, the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25 start driving. Then, based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled so that Y, M, C, K toner images are formed on the image carriers 1Y, 1M, 1C, 1K. It is formed. These toner images are superimposed and transferred onto the intermediate transfer belt 110 to form a four-color toner image.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding device 200 starts the paper feeding operation. In this paper feeding operation, one of the plurality of paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of paper feeding cassettes 44 provided in multiple stages in the paper bank 43. . When the transfer paper is sent out, the transfer paper is separated one by one by the separation roller 45, and the transfer paper enters the paper feed path 46 one by one. Thereafter, the sheet is conveyed toward the secondary transfer nip by the conveying roller pair 47. On the other hand, paper feed from the manual feed tray 51 may be performed instead of paper feed from the paper feed cassette 44. In this case, the manual paper feed roller 50 is selectively rotated, and the transfer paper is fed into the image forming apparatus by the manual paper feed roller 50. At this time, a plurality of transfer papers are to be transported as a unit by mutual frictional force, but because of the separation roller 52, the transfer papers are transported one by one. In this way, the transfer sheets are fed one by one to the manual feed path 53 of the printer unit 100.

Hereinafter, components of the image forming apparatus (the optical writing unit 21, the intermediate transfer unit 17, the secondary transfer device 22, and the fixing device 25) will be described. The description will be made on the assumption that a full-color image is formed.
First, the optical writing unit 21 will be described. The optical writing unit 21 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of the image carrier 1 with laser light based on image data. As a result, the surface potential of the image carrier 1 uniformly charged by the charging device is attenuated at the portion irradiated with the laser beam. By this attenuation, an electrostatic latent image is formed on the surface of the image carrier 1. The electrostatic latent image formed in this way is developed by the developing devices 7Y, 7M, 7C, and 7K to become a toner image.
The toner image formed on the image carrier 1 is primarily transferred to the intermediate transfer belt 110. Since toner remains on the surface of the image carrier 1 after the primary transfer, the surface of the image carrier 1 is cleaned by the cleaning device. Then, after passing through the lubricant application device, the charge is removed by the static eliminator, uniformly charged by the charging device, and returned to the initial state.

  Next, the intermediate transfer unit 17 will be described. The intermediate transfer unit 17 includes an intermediate transfer belt 110 and a belt cleaning device 90. The intermediate transfer unit 17 includes a driven roller 14, a drive roller 15, a secondary transfer roller 16, and four primary transfer rollers 62Y, 62M, 62C, 62K. The intermediate transfer belt 110 is stretched by a plurality of rollers including the driven roller 14. The intermediate transfer belt 110 moves endlessly by the rotation of the driving roller 15 driven by a motor. The four primary transfer rollers 62Y, 62M, 62C, 62K are arranged so as to be in contact with the inner peripheral surface of the intermediate transfer belt 110, respectively, and a primary transfer bias voltage is applied from a power source (not shown). Further, the primary transfer rollers 62Y, 62M, 62C, 62K press the intermediate transfer belt 110 from the inner peripheral surface thereof toward the image carriers 1Y, 1M, 1C, and 1K to form a primary transfer nip. Due to the influence of the primary transfer bias voltage, a primary transfer electric field is formed between the image carrier 1Y, M, C, K and the primary transfer roller 62Y, M, C, K (primary transfer nip).

The Y toner image formed on the image carrier 1Y is primarily transferred to the intermediate transfer belt 110 due to the influence of the primary transfer electric field and nip pressure. M, C, and K toner images formed on the image carriers 1M, 1C, and 1K are sequentially superimposed on the Y toner image. By this superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image), which is a multiple toner image, is formed on the intermediate transfer belt 110.
The four-color toner image transferred to the intermediate transfer belt 110 is transferred to transfer paper at the secondary transfer nip. The intermediate transfer belt 110 in which the toner remains on the surface after passing through the secondary transfer nip is sandwiched between the driven roller 14 and the belt cleaning device 90, where it is cleaned by the belt cleaning device 90.

  Next, the secondary transfer device 22 will be described. The secondary transfer device 22 is provided below the intermediate transfer unit 17. Further, the secondary transfer device 22 includes a paper transport belt 24 stretched by two stretch rollers 23. The paper transport belt 24 moves endlessly as the at least one of the stretching rollers 23 rotates. Of the two stretching rollers 23, the stretching roller 23 disposed on the right side in the drawing is paired with the secondary transfer roller 16 and sandwiches the intermediate transfer belt 110 and the paper transport belt 24. By this sandwiching, the intermediate transfer belt 110 and the paper transport belt 24 come into contact with each other to form a secondary transfer nip. A secondary transfer bias voltage having a polarity opposite to that of the toner is applied to the right tension roller 23. By applying the secondary transfer bias voltage, a secondary transfer electric field in which the toner electrostatically moves from the intermediate transfer belt 110 toward the stretching roller 23 in the secondary transfer nip is formed. Then, the four-color toner image is transferred to the transfer sheet fed to the secondary transfer nip by the registration roller pair 49 so as to be synchronized with the four-color toner image transferred to the intermediate transfer belt 110 due to the influence of the secondary transfer electric field and the nip pressure. Is transcribed. Instead of applying the secondary transfer bias voltage to the stretching roller 23, a method of charging the transfer paper in a non-contact state with a charging charger may be employed.

In the paper feeding device 200 provided at the lower part of the main body of the image forming apparatus, a plurality of paper feeding cassettes 44 capable of storing a plurality of transfer papers in a bundled state are arranged at intervals in the vertical direction. A paper feed roller 42 is pressed against the uppermost transfer paper of the paper feed cassette 44. Then, by rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46.
A plurality of conveyance roller pairs 47 and a registration roller pair 49 provided near the end of the paper feed path 46 are provided in the paper feed path 46 that receives the transfer paper fed from the paper feed cassette 44. The transfer paper is conveyed toward the registration roller pair 49 via the conveyance roller pair 47. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49. On the other hand, the four-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip with the endless movement of the belt. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the four-color toner image can be transferred in the secondary transfer nip. As a result, the four-color toner image on the intermediate transfer belt 110 is transferred to the transfer paper at the secondary transfer nip. The transfer paper on which the full-color image is printed in this manner is moved along with the endless movement of the paper transport belt 24, and then sent from the paper transport belt 24 to the fixing device 25.

Finally, the fixing device 25 will be described. The fixing device 25 includes a belt unit which is a device that moves the fixing belt 26 endlessly while being stretched by two rollers, and a pressure roller 27 that presses the fixing belt 26. The fixing belt 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper received from the paper transport belt 24 is sandwiched therebetween. Of the two rollers in the belt unit, the roller that is pressed by the pressure roller 27 includes a heat source (not shown) inside, and heats the fixing belt 26 by the heat generated by the roller. The heated fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.
The transfer sheet on which the fixing process has been performed by the fixing device 25 is discharged to a stack portion 57 protruding from the left side plate in the figure of the printer housing, or is formed on the other side in order to form a toner image. Return to the next transfer nip.

  When forming a monochrome image consisting of only K toner, the intermediate transfer belt 110 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface of the image carrier 1Y, M, Separate from C. Of the four image carriers 1Y, 1M, 1C, and 1K, only the image carrier 1K is rotated to form only the K toner image. At this time, for Y, M, and C, not only the image carrier 1 but also the driving of the developing device 7 is stopped.

  FIG. 2 shows details of the developing device 7. In the developing device 7, a developing roller 72 that contacts the image carrier 1 and applies toner to the electrostatic latent image formed on the image carrier is provided inside the vertically long toner container 71. Further, the developing device 7 is provided with a toner supply roller 73 that is a toner replenishing member that contacts the developing roller 72 that is a developer carrying member and supplies toner to the developing roller 72. A toner agitating member 74 for agitating the toner is provided in the vicinity of the upper side of the toner supply roller 73. The toner agitating member 74 has a function of agitating and circulating the toner in the toner accommodating portion 71 to prevent toner retention. Above the toner agitating member 74, a toner agitating member 75 disposed near the center of the toner accommodating portion 71 is provided to agitate the toner in the toner accommodating portion 71 as a whole.

A layer thickness regulating member 76 for forming a toner thin layer is provided on the peripheral surface of the developing roller 72. The front end side of the bent portion 76a of the layer thickness regulating member 76 is bent in a straight line obliquely upward, and the layer thickness regulating member 76 has an L-shaped cross section. The bent portion 76 a of the layer thickness regulating member 76 is in contact with the peripheral surface of the developing roller 72. The toner stirring member 74 is provided below an extended line (two-dot chain line in the figure) of the tip 76b of the layer thickness regulating member 76. More specifically, the peripheral line at the tip of the toner stirring member 74 is positioned below the extension line. By arranging the toner stirring member 74 in this way, the toner on the developing roller 72 that cannot pass through the layer thickness regulating member 76 can be conveyed onto the toner supply roller 73. As shown in FIG. 3, if the toner stirring member 74 is present on the extension line of the layer thickness regulating member 76, the toner flow scraped off by the layer thickness regulating member 76 is inhibited, and the toner stays. May not be sufficiently prevented.
The shortest distance between the peripheral line at the tip of the toner stirring member 74 and the extension line is set to 5 mm or less. The reason why the shortest distance is 5 mm or less is that if it exceeds 5 mm, the conveying force by the toner stirring member 74 is difficult to be transmitted.
The bending angle θ (shown in FIG. 4) of the distal end portion 76b of the layer thickness regulating member 76 is 90 ° or less. This is to prevent the toner flow in the vicinity of the front end portion 76b from being obstructed.

  In the drawing, the developing roller 72 and the toner supply roller 73 are rotated in the counterclockwise direction, and the toner stirring member 74 is rotated in the clockwise direction. The linear speed ratio (stirring linear speed / replenishment linear speed) of the toner stirring member 74 and the toner supply roller 73 is 1.5 or more. The toner can be easily peeled off from the toner supply roller 73, the flow of toner around the toner supply roller 73 is improved, and the flow of toner stirred by the toner stirring member 74 is increased, so that the tip of the layer thickness regulating member 76 The retention of toner 76b can be prevented. If the linear speed ratio is 1.0, the toner supply roller 73 and the toner agitating member 74 are moving at the same speed at the closest portion, and the recovery of toner from the toner supply roller 73 is not good. In order to improve the recoverability, there is a method in which the toner supply roller 73 and the toner agitating member 74 are rotated in opposite directions. In this case, the toner is near the tip 76b of the layer thickness regulating member 76. It stays and the circulation of toner becomes insufficient.

Next, the toner according to the present invention will be described.
In order to reproduce minute dots of 600 dpi or more, the volume average particle diameter (Dv) is 3 to 8 μm, and the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1. Toner in the range of 00 to 1.40 is used. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the volume average particle diameter (Dv) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. When the volume average particle diameter (Dv) exceeds 8 μm, it is difficult to suppress scattering of characters and lines. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

Next, a method for measuring the particle size distribution of toner particles will be described.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter Counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the weight and number of toner particles or toner using a 100 μm aperture as an aperture. Calculate weight distribution and number distribution. From the obtained distribution, the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner can be obtained.

As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. This is because the fluidity of the toner is good within such a range. 5 and 6 are diagrams schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) ² / AREA} × (100 / 4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

When the shape of the toner is close to a sphere, the contact state between the toner and the toner or the toner and the image carrier becomes point contact, so that the attractive force between the toners is weakened and the fluidity is increased. The adsorption force with the carrier is also weakened, and the transfer rate is increased. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.
The toner suitably used in the image forming apparatus of the present invention includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by a crosslinking reaction and / or an elongation reaction in an aqueous solvent. Such toner has good fluidity.

FIG. 1 is an explanatory view showing an embodiment of the image forming apparatus of the present invention. FIG. 2 is an explanatory view showing an embodiment of the developing device of the present invention. FIG. 3 is an explanatory view showing an example of a developing device in which an undesired layer thickness regulating member is used. FIG. 4 is an explanatory view showing details of the layer thickness regulating member. FIG. 5 is a diagram schematically illustrating the shape of the toner in order to explain the shape factor SF-1. FIG. 6 is a diagram schematically showing the shape of the toner for explaining the shape factor SF-2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 7 Developing apparatus 71 Toner accommodating part 72 Developing roller 73 Toner supply roller 74 Toner stirring member 75 Toner stirring member 76 Layer thickness regulating member 76a Bending part 76b Front end part 14 Followed roller 15 Drive roller 16 Secondary transfer roller 17 Intermediate transfer unit 18 Process cartridge 20 Image forming unit 21 Optical writing unit 22 Secondary transfer device 23 Stretching roller 24 Paper transport belt 25 Fixing device 26 Fixing belt 27 Pressure roller 30 Document table 31 Document discharge unit 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 42 Paper feed roller 43 Paper bank 44 Paper feed cassette 45 Separating roller 46 Paper feed path 47 Transport roller pair 49 Registration roller pair 50 Manual paper feed roller 51 Manual feed tray 52 Separation B Roller 53 Manual feed path 57 Stack unit 62 Primary transfer roller 90 Belt cleaning device 100 Printer unit 110 Intermediate transfer belt 200 Paper feed device 300 Scanner unit main body 400 Automatic document feeder

Claims (9)

A layer thickness regulating member for forming a developer carrier and a toner thin layer;
A toner replenishing member that supplies toner to the developer carrying member;
A toner agitating member for circulating the toner in the toner container;
In a developing device having
The toner stirring member is provided below the extension line of the tip portion on the tip side of the bent portion of the layer thickness regulating member, and the shortest distance between the peripheral line at the tip of the toner stirring member and the extension line is 5 mm. A developing device comprising: The developing device according to claim 1,
A developing device, wherein a linear speed ratio (stirring linear speed / replenishment linear speed) of the toner agitating member and a toner replenishing member is 1.5 or more. In the developing device according to claim 1 or 2,
The developing device, wherein a bending angle of a tip portion of the layer thickness regulating member is 90 ° or less. The developing device according to any one of claims 1 to 3,
A toner having a volume average particle diameter (Dv) of 3 to 8 μm and a ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) (Dv / Dn) in the range of 1.00 to 1.40. A developing device characterized by being used. In the developing device according to any one of claims 1 to 4,
A developing device using a toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. The developing device according to any one of claims 1 to 5,
Development obtained by subjecting a toner material liquid in which a polyester prepolymer having a functional group containing at least a nitrogen atom, polyester, a colorant, and a release agent to an organic solvent to a crosslinking reaction and / or an extension reaction in an aqueous medium. A developing device characterized by being an agent. A process cartridge comprising the developing device according to claim 1. An image forming apparatus comprising the developing device according to claim 1. An image forming apparatus comprising the process cartridge according to claim 7.

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