JP2012155008A - Developing device, image forming device and developing method - Google Patents

Abstract

In a two-component developing type developing device, the density uniformity of a developer layer immediately before a developing region is improved.
A developing sleeve has a magnetic force generating means inside the developing sleeve, and the developer is transported to the developing area of the photosensitive member while developing on the surface of the developing sleeve by a magnetic force generated by the magnetic force generating means. In the developing device to be performed, the first developer regulating member 52Y disposed in the vicinity of the developing sleeve 51Y and the downstream side of the developer conveying direction (R4 direction) from the first developer regulating member 52Y, the conveying direction A second developer regulating member 56Y disposed in the vicinity of the developing sleeve 51Y immediately before the downstream developing electrode P2, and a gap between the second developer regulating member 56Y and the developing sleeve 51Y It was made narrower (d2> d1) from upstream to downstream in the transport direction.
[Selection] Figure 4

Description

  The present invention relates to a developing device that develops a latent image by an electrophotographic method, an image forming apparatus including the developing device, and a developing method that is executed by each of these devices.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a developer is carried on a developer carrying member, and the developer carried on the developer carrying member is regulated by a developer regulating member (doctor blade), and then a photoreceptor. 2. Description of the Related Art A developing device that conveys a developing area facing an image carrier such as the like is known. In a developing device using a two-component developer composed of a magnetic carrier and toner as a developer, a developing sleeve having a magnetic field generating means inside is used as an image carrier. The developing sleeve carries the developer contained in the developing device on the developing sleeve by the magnetic force of the internal magnetic field generating means, and conveys the carried developer to the developing area facing the photoreceptor by rotating. The developer carried on the developing sleeve becomes a certain amount by passing through a gap with the developer regulating member arranged to face the developing sleeve surface with a certain distance (doctor gap) on the way. Be regulated.

  The amount of developer per unit area that has passed through the doctor gap is called the pumping amount. If the pumping amount is too large relative to the gap between the developing areas where the developing sleeve and the photoconductor face each other, the developer presses in the developing area, and frictional heat is generated due to shear stress at that time, and the developer itself dissolves. The problem of sticking occurs.

  On the other hand, when the pumping amount is small, sufficient toner cannot be supplied to the photosensitive member, resulting in a problem that the image density is lowered. For this reason, in order to stably obtain a high-quality image, it is necessary to secure an appropriate pumping amount and to convey it to a portion facing the photoconductor. Further, as the developer regulating member, a metal plate member or a round bar member is widely used.

  As a technique for solving such a problem, for example, an invention described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2009-09834) is known. In the present invention, in order to eliminate the difference in the toner charge amount immediately after the start of printing and during continuous printing and to stabilize the toner charge amount, the developer is carried on the surface and conveyed to the latent image carrier and the latent image is transferred. A developer carrying member that forms an image on the carrying member, a developer regulating member that is disposed on the upstream side of the developer carrying member from an image forming position on the carrying member and regulates the amount of the developer on the developing carrier; In the developing device having the above, a front regulating member capable of changing a distance between the developer carrying member and an upstream side of the developer regulating member is arranged.

  However, in the invention described in Patent Document 1, the difference in toner charge amount between immediately after the start of printing and during continuous printing can be eliminated, and the toner charge amount can be stabilized. The unevenness of the agent layer cannot be eliminated.

  In other words, in the conventional developing apparatus including the invention described in Patent Document 1, the developer layer after passing the developer regulating member varies due to magnetic spikes waking up by the magnetic poles before being conveyed to the development area. Occurs. For this reason, the density of the developer layer in the development region becomes non-uniform compared with that after passing through the developer regulating member. If the density of the developer in the development area is non-uniform, the length of the magnetic spikes becomes non-uniform and the graininess of the image deteriorates.

  Therefore, the problem to be solved by the present invention is to improve the uniformity of the density of the developer layer immediately before the development area in the two-component development type development apparatus.

  In order to solve the above-mentioned problem, the first means has a magnetic force generating means inside the developer carrying member, and carries the image on the surface of the developer carrying member by the magnetic force generated by the magnetic force generating means. A developing device for carrying out development by transporting the developer to a developing region of a body, wherein the first developer regulating member is disposed in proximity to the developer carrying member, and the first developer regulating member A second developer regulating member disposed in the vicinity of the developer carrying body immediately before the development pole downstream of the developer transport direction and downstream of the developer region in the transport direction, The gap between the second developer regulating member and the developer carrier is set so as to become narrower from the upstream to the downstream in the transport direction of the developer.

  In this case, the gap between the first developer regulating member and the developer carrying member is d0, and the gap between the second developer regulating member and the narrowed portion on the downstream side of the developer carrying member is made. When d1, the ratio d1 / d0 of both is set in the range of 0.7-1.

  Further, the second developer regulating member is constituted by a flat plate member or a cylindrical member. When a cylindrical member is used as the second developer regulating member, it is desirable to coat the surface of the cylindrical member with a material having a friction coefficient of 0.2 or less. Furthermore, the rotation direction of both is set so that the surface of the developer carrying member and the surface of the cylindrical member as the second developer regulating member facing the developer carrier move in the same direction.

  The second means is characterized in that the image forming apparatus includes the developing device according to the first means.

  The third means includes a magnetic force generating means inside the developer carrying member, and the developer is carried on the surface of the developer carrying member by the magnetic force generated by the magnetic force generating means, and the developing is performed on the developing area of the image carrier. A developing method for carrying out development by transporting the developer, the step of regulating the pumping amount of the developer to a fixed amount by a first developer regulating member disposed in the vicinity of the developer carrying member; The pumping amount is regulated at a constant level in the step by the second developer regulating member disposed in the vicinity of the developer carrying member downstream of the developer regulating member in the developer transport direction and immediately before the developing pole. And a step of adjusting the density of the developer layer and transporting the developer to the development area.

  In the embodiment described later, the developer carrying member is the developing sleeve 51Y, the developer is the symbol T, the developing device is the symbol 5Y, and the first developer regulating member is the first developer regulating member (doctor) 52Y. In addition, the developing electrode is denoted by reference numeral P2, the second developer restricting member is denoted by the second developer restricting member 56Y, the gap is denoted by numerals d1 and d2, and the second developer restricting member made of a flat plate member is denoted by the second developer. The second developer regulating member made of a cylindrical member corresponds to the regulating member 56Y, the second developer regulating member 561Y, and the image forming apparatus corresponds to the printer 100.

  According to the present invention, in the two-component developing type developing apparatus, it is possible to improve the uniformity of the density of the developer layer immediately before the developing region.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to Example 1 in an embodiment of the present invention. FIG. 2 is an enlarged view showing a developing device in FIG. 1. FIG. 3 is an enlarged view of a main part of FIG. 2 and shows a relationship between a developing sleeve and a developer regulating member. It is a figure which shows the normal direction magnetic flux density distribution on the image development sleeve by the magnetic force generation means inside a image development sleeve. FIG. 5 is an enlarged view showing a front end portion of a second developer regulating member in FIG. 4. FIG. 6 is a schematic diagram illustrating a state of a developer between a second developer regulating member and a developing sleeve. It is the figure which showed the experimental condition (1) in the measurement experiment of a granularity rank in tabular form. It is the figure which showed the experimental condition (2) in the measurement experiment of a granularity rank in tabular form. It is the figure which showed the experimental result in the case of experimental condition (1) in the graph format. It is the figure which showed the experimental result in the case of experimental condition (2) in the graph format. 6 is a schematic diagram illustrating a state of a developer between a developing sleeve and a second developer regulating member in Embodiment 2. FIG. It is the figure which showed the experimental condition (3) in the measurement experiment of a developer lifetime in tabular form. It is the figure which showed the experimental result in the case of the experimental condition (3) in Example 2 in the graph format.

  According to the present invention, in the developer regulating member in the two-component developing device, after the pumping amount is regulated to a certain amount by the first developer regulating member, the density of the developer layer is adjusted by the second developer regulating member. Features.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to Example 1 of the present embodiment. The image forming apparatus according to the first exemplary embodiment is an electrophotographic printer (hereinafter simply referred to as a printer), and forms an image on a sheet-like recording medium based on image data input from the outside. In this printer, a process cartridge is used for the image forming unit.

  In FIG. 1, the printer 100 includes four process cartridges 6Y, 6M, 6C, and 6K for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). An image forming unit provided, an optical writing unit that performs optical writing to the image forming unit, an intermediate transfer unit that primarily transfers an image formed by the image forming unit, and an image transferred by the intermediate transfer unit in a sheet form A secondary transfer section for secondary transfer to a recording medium, a paper feed section for supplying a sheet-like recording medium to the secondary transfer section, a fixing section for fixing the secondary transferred image on the sheet-like recording medium, and an image Is basically composed of a paper discharge unit that discharges the sheet-like recording medium on which is fixed to the stack unit 30.

  The four process cartridges 6Y, 6M, 6C, and 6K in the image forming unit use Y, M, C, and K toners of different colors as image forming materials. It is exchanged when it arrives.

  FIG. 2 is an enlarged view of the developing device of FIG. Taking a process cartridge 6Y for generating a Y toner image as an example, as shown in FIG. 2, a drum-shaped photosensitive member 1Y, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device 4Y, a developing device 5Y, etc. I have. The process cartridge 6Y can be attached to and detached from the printer 100 main body, so that consumable parts can be replaced together.

  The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that is driven to rotate clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry an electrostatic latent image for Y. The Y electrostatic latent image is developed into a Y toner image by the developing device 5Y using Y toner. Then, intermediate transfer is performed on an intermediate transfer belt 8 as an intermediate transfer portion. The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process. Further, the static eliminator neutralizes residual charges on the photoreceptor 1Y after cleaning. By this charge removal, the surface of the photoreceptor 1Y is initialized and prepared for the next image formation. In the other process cartridges 6M, 6C, and 6K, M, C, and K toner images are similarly formed on the photoreceptors 1M, 1C, and 1K, and are intermediately transferred onto the intermediate transfer belt 8.

  In FIG. 1 shown above, an exposure device 7 serving as an optical writing unit is disposed below the process cartridges 6Y, 6M, 6C, and 6K.

  The exposure device 7 exposes the respective photosensitive members in the process cartridges 6Y, 6M, 6C, and 6K to the laser light L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photosensitive member through a plurality of optical lenses and mirrors while scanning a laser beam L emitted from a light source with a polygon mirror rotated by a motor.

  On the lower side of the exposure apparatus 7 in the figure, a paper supply unit having a paper storage cassette 26, a paper supply roller 27 incorporated therein, a registration roller pair 28, and the like is disposed. The paper storage cassette 26 stores a plurality of transfer papers P as sheet-like recording media, and a paper feed roller is in contact with each uppermost transfer paper P. When the paper feeding roller 27 is driven to rotate counterclockwise in the drawing by a driving means (not shown), the uppermost transfer paper P is fed toward the nip of the registration roller pair 28. When the registration roller pair 28 is stopped, the transfer paper P is brought into contact with the nip of both rollers, the leading edge of the transfer paper P is aligned, and then both rollers are rotationally driven to pinch the transfer paper P. Immediately stop the rotation. Then, the transfer paper P is sent out toward the secondary transfer section described later in time with the timing of the leading end of the primary transfer image on the intermediate transfer belt 8. In the sheet feeding unit configured as described above, a conveying unit is configured by a combination of the sheet feeding roller 27 and the registration roller pair 28 functioning as a timing roller pair. This transport means transports the transfer paper P from the paper storage cassette 26 to the secondary transfer nip of the secondary transfer unit.

  Above the process cartridges 6Y, 6M, 6C, and 6K in the figure, an intermediate transfer unit 15 that rotates and moves an endless intermediate transfer belt 8 stretched between rollers described later is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 includes four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a cleaning device 10, and the like. A secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14 and the like are also provided. The intermediate transfer belt 8 is rotated in the direction of the arrow R3 (counterclockwise) in the figure by the rotational drive of at least one of the rollers 12, 13, and 14 while being stretched between the three rollers 12, 13, and 14.

  The primary transfer bias rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 between the photoreceptors 1Y, 1M, 1C, and 1K to form primary transfer nips. In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All the rollers except the primary transfer bias rollers 9Y, 9M, 9C, and 9K are electrically grounded. In the intermediate transfer belt 8, Y, M, C on the photoreceptors 1 Y, 1 M, 1 C, and 1 K are sequentially passed through the primary transfer nips for Y, M, C, and K along with the endless movement. The K toner images are superimposed and primarily transferred onto the intermediate transfer belt 8. As a result, a toner image in which four colors are superimposed on the intermediate transfer belt 8 (hereinafter referred to as a four-color toner image) is formed.

  The secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 between the secondary transfer roller 19 and forms a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the transfer paper P at the secondary transfer nip. Untransferred toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the cleaning device 10 arranged immediately downstream of the cleaning backup roller 13.

  In the secondary transfer nip, the transfer paper P is sandwiched between the intermediate transfer belt 8 whose surface moves in the forward direction and the secondary transfer roller 19 and is conveyed downstream with respect to the registration roller pair 28 side. Is done. When the transfer paper P sent out from the secondary transfer nip passes between rollers of the fixing device 20 as a fixing unit, the four-color toner image transferred to the surface is fixed by heat and pressure. Thereafter, the transfer paper P is discharged out of the apparatus through a pair of paper discharge rollers 29.

  A stack unit 30 is formed on the upper surface of the printer body, and the transfer paper P discharged outside the apparatus by the discharge roller pair 29 is sequentially stacked on the stack unit 30. However, in the present embodiment, the paper discharge roller 29 and the stack unit 30 constitute a paper discharge unit.

  As shown in FIG. 2, the developing device 5Y in the process cartridge 6Y includes a magnetic field generating means, and develops as a developer carrying member that carries and conveys a two-component developer containing magnetic particles and toner on the surface. A sleeve 51Y and a doctor (first developer regulating member) 52Y as a developer regulating member that regulates the layer thickness of the developer carried and conveyed on the developing sleeve 51Y are provided. On the upstream side of the developer conveyance direction of the doctor 52Y, a uniaxial developer accommodating portion 53Y that accommodates the developer regulated by the doctor 52Y without being conveyed to the developing area facing the photoreceptor 1Y is formed. Further, a biaxial developer accommodating portion 54Y for supplying toner is formed adjacent to the uniaxial developer accommodating portion 53Y. Two developer conveying screws 55Y for agitating and conveying the developer are provided in the one-axis developer accommodating portion 53Y and the two-axis developer accommodating portion 54Y, respectively.

  In the developing device 5Y configured as described above, a developer layer is formed on the developing sleeve 51Y. The toner is replenished from the toner bottle 32Y positioned above the intermediate transfer unit 15 on the two-axis side of the developer conveying screw 55Y, is agitated and conveyed, and is taken into the developer. Specifically, the sensor output from the toner density sensor that detects the toner density in the toner bottle 53Y is input to the control unit 57Y, and the control unit 57Y detects the toner density in the developer. The control unit 57Y determines whether or not toner is to be taken in based on the detected toner density. When toner is to be taken in, the developer transport screw 55Y is driven by the drive motor 41Y to take in the toner from the toner bottle 32Y. This determination of toner uptake is made based on whether or not the toner concentration of the developer is within a predetermined range.

  The toner taken into the developer is charged by frictional charging with the carrier. The developer containing charged toner is supplied to the surface of the developing sleeve 51Y having a magnetic pole inside and is carried by magnetic force. The developer layer carried on the developing sleeve 51Y is conveyed in the direction of arrow R1 as the developing sleeve 51Y rotates. On the way, after the layer thickness of the developer layer is regulated by the first developer regulating member 52Y, the developer layer is made uniform by the second developer regulating member 56Y and conveyed to the developing area facing the photoreceptor 1Y. In the development area, development is performed based on the latent image formed on the photoreceptor 1Y while the photoreceptor 1Y rotates in the direction of the arrow R2. The developer layer remaining on the developing sleeve 51Y is conveyed to the upstream portion in the developer conveying direction of the uniaxial developer accommodating portion 53Y as the developing sleeve 51Y rotates.

  Not only the yellow toner bottle 32Y but also the magenta toner bottle 32M, the cyan toner bottle 32C, and the black toner bottle 32 are accommodated in a toner bottle accommodating portion 31 formed between the intermediate transfer unit 15 and the stack portion 30, and each color. Is supplied to the biaxial developer accommodating portion of each color process unit.

  FIG. 3 is a diagram showing a relationship between the developing sleeve and the developer regulating member, and shows an enlarged main part of FIG. In the drawing, a first developer regulating member (doctor) 52Y and a second developer regulating member 56Y are arranged below the developing sleeve 51Y. As shown in FIG. 3, the second developer restricting member 56Y is located downstream of the first developer restricting member 52Y in the rotational direction (in the direction of the arrow R1 in the drawing).

  FIG. 4 is a diagram showing a normal direction magnetic flux density distribution on the developing sleeve 51Y by the magnetic force generating means inside the developing sleeve 51Y. P1 is a pumping pole for pumping the developer from the developer container 53Y to the developing sleeve 51Y, and P2 is a developing pole for developing the latent image formed on the photoreceptor 1Y in the developing area. The first developer regulating member 52Y is disposed on the pumping pole P1, and the second developer regulating member 56Y is disposed between the pumping pole P1 and the developing pole P2. As described above, the second developer regulating member 56Y is arranged downstream of the first developer regulating member 52Y in the developer transport direction (in the direction of the arrow R4 in the figure) and immediately before the developing electrode P2, thereby developing the electrode P1. The density of the developer layer can be made uniform by the second developer restricting member 56Y immediately before rising. This makes it possible to form uniform magnetic spikes in the development area.

FIG. 5 is an enlarged view showing the tip of the second developer regulating member 56Y in FIG. In this embodiment, a plate member formed of SUS is used as the second developer regulating member 56Y. The second developer regulating member 56Y is fixed in a state where the tip end portion faces the developing sleeve 51Y. The gap between the second developer regulating member 56Y and the developing sleeve 51Y is disposed so as to narrow from the upstream to the downstream in the developer transport direction (the arrow R4 direction in the drawing). When the gap on the developer outlet side of the second developer regulating member 56Y is d1, and the gap on the developer inlet side is d2, d1 <d2
It has become.

FIG. 6 is a schematic diagram showing the state of the developer between the second developer regulating member 56Y and the developing sleeve 51Y. When the gap between the tip of the second developer regulating member 56Y and the developing sleeve 51Y gradually narrows as shown in FIG. 6 in the developer transport direction (arrow R4), the developer T is appropriately compressed, and the second development. The density of the developer after passing the agent regulating member 56Y can be made uniform. At this time, the pumping amount of the developer T is regulated by the first developer regulating member 52Y, and if the gap between the first developer regulating member 52Y and the developing sleeve 51Y is d0 as shown in FIG.
d0 = d2> d1
Since the gap d0 is set in such a relationship, excessive stress is not applied when compressed by the second developer regulating member 56Y, and the density of the developer T can be made uniform.

  The granularity rank when the second developer regulating member 56Y in this embodiment is used is shown in FIGS. This granularity rank indicates the result when the experiment was performed under the experimental conditions (1) and (2) in FIGS. The experimental condition is that the gap d0 (= distance) is constant, the gap d1 (= distance) is a variable, and the ratio d1 / d0 between the two is a parameter. The granularity rank is an index indicating the granularity of the output image. The larger the numerical value, the better the granularity. 9 and 10, it can be seen that when the ratio d1 / d0 is 1 or less, the density of the developer layer in the development region becomes uniform, and the granularity of the output image is improved. However, if the ratio d1 / d0 is made too small, there is a problem that the developer does not pass through the second developer regulating member 56Y and overflows, so the ratio d1 / d0 needs to be larger than 0.7. . Optimally, it is in the range of 0.7-1.

  In the present embodiment, the developing device 5Y in the process cartridge 6Y has been described, but the same applies to the developing devices 5M, 5C, and 5K in the process cartridges 6M, 6C, and 6K for other colors M, C, and K. Needless to say.

  FIG. 11 is a schematic diagram illustrating a state of the developer between the developing sleeve 51Y and the second developer regulating member 561Y in the second embodiment, and corresponds to FIG. 6 in the first embodiment. The second embodiment is the same as the first embodiment except for the second developer restricting member 561Y. Therefore, the same reference numerals are given to the same parts, and duplicate descriptions are omitted.

  The second developer regulating member 561Y in the second embodiment is configured by a cylindrical bar as shown in FIG. A plate-like member widely used as a developer regulating member is generally formed by press cutting, and then subjected to secondary processing such as cutting or polishing treatment and used as a uniform flat surface in the longitudinal direction. Producing in this way is costly because of many processes. On the other hand, when using a round bar, since it can form by extrusion molding, it can be made low-cost compared with a plate-shaped member.

  Therefore, when a round bar is used as the second developer regulating member 561Y, the round bar faces the developing sleeve 51Y with a curvature. With such a relative relationship, as in the first embodiment, the gap between the developing sleeve 51Y and the second developer regulating member 561Y narrows from upstream to downstream in the developer transport direction (arrow R4 direction). Become. Therefore, the density of the developer layer becomes uniform, and an image with good graininess can be obtained. At that time, since the developer conveyed to the second developer regulating member 561Y is regulated to a constant amount at the interval d0 of the first developer regulating member 52Y as in the first embodiment, the second developer regulating is performed. The density of the developer layer can be made uniform without excessive stress applied by the member 561Y. In this example, a cylindrical bar made of aluminum having a diameter of 10 mm was used.

  Further, the second developer regulating member 561Y made of a cylindrical bar is rotatably supported, receives power from a driving source (not shown), and the surface of the developing sleeve 51Y and the surface of the second developer regulating member 561Y are in the same direction. It can be rotated in the direction of movement (arrow R1 direction and arrow R5 direction). When the second developer regulating member 561Y is thus rotated, the stress on the developer due to friction between the second developer regulating member 561Y and the developer is reduced, and the life of the developer can be extended.

  Also, a PTFE (polytetrafluoroethylene) coat layer can be formed on the surface of the second developer regulating member 561Y. Since PTFE is a substance having a very small friction coefficient, when a PTFE coating layer is formed, it is possible to further reduce stress on the developer T due to friction between the second developer regulating member 561Y and the developer T. The life of the developer T can be further extended. In the second embodiment, PTFE is used as the coating material, but it goes without saying that other materials having a low friction coefficient can be used without being limited to PTFE.

  FIG. 13 shows the developer life when the second developer regulating member 561Y in this embodiment is used. This developer life shows the result when the experiment was conducted under the experimental condition (3) in FIG. In this experiment, the cylindrical rod formed of aluminum having a diameter of 10 mm is used as the second developer regulating member 561Y, and the developer is used for the combination of rotation / non-rotation of the cylindrical rod and presence / absence of the PTFE coat. Lifetime is measured. Here, the life of the developer T is determined by the number of output sheets until the developer T is scraped and the developer T becomes finely powdered, resulting in deterioration of charging characteristics and resulting in background contamination. ing.

The measurement of the friction coefficient μ shown in FIG. 12 was performed using an atomic force microscope. The outline of an atomic force microscope and an adhesion force measuring method using the same will be described below.
There are many known documents (for example, Appl. Phys. Lett. 56, 1758 (1990)) regarding the principle of operation of an atomic force microscope (AFM). Using a cantilever having a needle having a material surface such as silicon nitride or silicon dioxide (probe tip, hereinafter also referred to as a tip) at the tip, the tip is brought close to the measurement sample surface, and between the sample surface and the probe tip The force acting on the surface (surface force) or the friction force between the sample and the cantilever is measured as the cantilever warpage or deflection using the reflection of the photodiode, and is linked to feedback control as a signal between the tip and the sample surface. Controlling the distance with a piezo element is a typical AFM operating principle.
When measuring adhesion or frictional force using an atomic force microscope, the cantilever must be decorated. Specifically, the target powder is attached to the cantilever tip with an adhesive such as an epoxy resin. The attaching operation can be performed by using a dedicated device as described in JP-A-2002-62253 or by AFM.

  The frictional force can be calculated based on SII Nano Technology Co., Ltd. Application Brief SPI no.37 “Quantitative Friction Characteristic Evaluation I by Friction Curve I”.

Below, the measurement conditions in a present Example are shown.
Measurement conditions (frictional curve method): atomic force microscope (AFM): scanning probe microscope SPI4000, multifunctional unit SPA400 (manufactured by SII Nanotechnology Co., Ltd.)
・ Measurement mode: AFM mode
Cantilever: Silicon cantilever SI-DF20 manufactured by SII Nano Technology Co., Ltd., spring constant: 20 [N / m]
・ Scanning conditions: 10000 [nm], reciprocating scan at 0.2 Hz
・ Loading condition: Set with the aim of 0, 1500, 5000 [nN] pressing load between the cantilever tip and sample surface
・ Carrier particle size at the tip of the cantilever: 35 [μm]
・ Career type: Carrier made by Ricoh Co., Ltd.
・ Friction force calculation method: SII Nano Technology Co., Ltd. Application Brief SPI no.37 Calculated according to the contents of “Quantitative friction characteristic evaluation I by frictional curve” ・ Friction coefficient calculation method: Primary change of friction force against pressing load Calculated with

  When the coefficient of friction of the second developer regulating member of this example was measured by this measurement method, μ = 0.2 when PTFE was coated, and μ = 0.5 when PTFE was not coated.

  FIG. 13 shows the result of the experiment performed under the experimental condition (3) in FIG. From FIG. 13, when the second developer regulating member 561Y is rotated, the developer life is improved as compared with the case where the second developer regulating member 561Y is not rotated. Compared to the case where the PTFE is coated on the second developer regulating member 561Y. It can be seen that the developer life is improved.

  The lifetime can be improved in this way, whether the second developer regulating member 561Y has been rotated or the member has been coated, in which case the developer has a gap (d2 → d1). This is considered to be because the stress applied to the developer when passing through can be reduced.

  In the second embodiment, the developing device 5Y in the process cartridge 6Y is described, but the developing devices 5M, 5C, and 5K in the process cartridges 6M, 6C, and 6K for other colors M, C, and K are also used. It is the same.

  As described above, according to the present embodiment, the developer developer density is adjusted by the second developer regulating members 56Y and 561Y after the pumping amount of the developer T is regulated by the first developer regulating member 52Y. Then, the developer T is transported to the development area formed by the development electrode P2. Since the second developer regulating members 56Y and 561Y have a shape in which the gap (doctor gap) with the developing sleeve 51Y becomes narrower from the upstream to the downstream in the developer transport direction (the gap decreases from d2 to d1). Appropriate pressure is applied to the developer T, and the density of the developer layer and the surface height of the developer layer become uniform. As a result, the uniformity of the developer layer after passing through the second developer regulating members 56Y and 561Y can be improved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention, and all technical matters included in the technical idea described in the claims are included. The subject of the present invention. Each of the above examples shows a preferred embodiment, but those skilled in the art will realize various alternatives, modifications, variations, and improvements from the contents disclosed in this specification. Which fall within the scope defined by the appended claims.

5Y developing device 51Y developing sleeve 52Y first developer regulating member (doctor)
56Y, 561Y Second developer regulating member 100 Printer d0, d1, d2 Gap P2 Developer pole T Developer

JP 2009-09834 A

Claims (8)

The developer carrying member has a magnetic force generating means, and the developer is carried to the developing area of the image carrier while developing on the surface of the developer carrying member by the magnetic force generated by the magnetic force generating means. A developing device for performing
A first developer regulating member disposed in proximity to the developer carrier;
A second developer disposed in the vicinity of the developer carrying member, downstream of the first developer regulating member in the developer transport direction and immediately before the development pole on the downstream side of the developer transport direction; A regulating member;
With
The developing device, wherein a gap between the second developer regulating member and the developer carrying member is set so as to become narrower from an upstream side to a downstream side in the transport direction of the developer. The developing device according to claim 1,
The gap between the first developer regulating member and the developer carrying member is d0, and the gap between the second developer regulating member and the narrowed portion on the downstream side of the developer carrying member is d1. The developing device is characterized in that the ratio d1 / d0 of the both is in the range of 0.7-1. The developing device according to claim 1 or 2,
The developing device, wherein the second developer regulating member is a flat plate member. The developing device according to claim 1 or 2,
The developing device, wherein the second developer regulating member is a cylindrical member. The developing device according to claim 4,
A developing device, wherein the surface of the cylindrical member is coated with a material having a friction coefficient of 0.2 or less. The developing device according to claim 4 or 5, wherein
2. A developing device according to claim 1, wherein the rotation direction of the developer carrying member and the surface of the second developer regulating member opposed to the surface of the developer carrying member are set in the same direction.   An image forming apparatus comprising the developing device according to claim 1. The developer carrying member has a magnetic force generating means, and the developer is carried to the developing area of the image carrier while developing on the surface of the developer carrying member by the magnetic force generated by the magnetic force generating means. A development method for performing
A step of regulating the pumping amount of the developer to a constant amount by the first developer regulating member disposed in the vicinity of the developer carrying member;
The second developer regulating member disposed in the vicinity of the developer carrying member downstream of the first developer regulating member in the developer transport direction and immediately before the development pole makes the pumping amount constant in the step. Adjusting the density of the regulated developer layer and conveying the developer to the development area;
A developing method characterized by comprising:

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