JP2009086554A - Developing device, cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device in which even when a developer carrier is not incorporated, a toner regulating member can be stably held by a support member and positioned, and easy assembly is ensured, and to provide a cartridge and an image forming apparatus. <P>SOLUTION: A developer quantity regulating means 4 incudes: a sheet-like regulating member 40 disposed in contact with the developer carrier 3; and a support member 42 supporting the regulating member 40. The regulating member 40 is supported in contact with the support member 42 by elastic force produced as a result of curving the regulating member 40 sidewise along its lengthwise direction and/or by elastic force produced as a result of pressing the regulating member against the developer carrier 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device for developing an electrostatic latent image formed on an image carrier, a cartridge provided with such a developing device, and further provided with a developing device or the cartridge being detachable. The present invention relates to an image forming apparatus.

  Conventionally, as a developing method using a one-component developer (toner), a contact developing method and a non-contact developing method are widely used. Specifically, (1) a contact development method using a developing roller having an elastic layer as a developer carrier, and (2) a non-contact development method using a magnetic toner using a metal sleeve as a developer carrier are proposed. Has been. In these development systems, several measures have been proposed as developer amount regulating means for forming a thin layer of one-component toner on the developer carrying member, that is, toner regulating means.

(1) Contact development method using a developing roller having an elastic layer As shown in FIG. 9, a contact development method is performed on a developing roller 3 that is an elastic roller having a dielectric layer as a developer carrier. A developing device D that carries a magnetic developer and performs development by bringing it into contact with the surface of a photosensitive drum 1 that is an image carrier is widely known. In the contact developing type developing device D, the supply of the developer to the developing roller 3 is performed by the supply roller 5 in contact with the developing roller 3. The supply roller 5 carries the developer from the inside of the developing container T, adheres to the developing roller 3, and also has a function of temporarily removing the developer remaining on the developing roller 3.

  Charge regulation by the layer regulation of the developer adhered on the developing roller 3 and frictional charging is performed by bringing the toner regulating means 4 c into contact with the developing roller 3. That is, as the toner regulating means 4c, it has been proposed that a blade-shaped thin metal plate (that is, a toner regulating member) 4c2 is cantilevered by the support member 4c1, and the abdominal surface of the opposed portion is brought into contact with the developing roller 3. Yes. The developer coated on the developing roller 3 by the toner regulating member 4c2 converts the electrostatic latent image by the electrostatic latent image formed on the photosensitive drum 1 and the bias potential applied on the developing roller 3. develop.

(2) Non-contact development method using magnetic toner using a metal sleeve As a non-contact development method, as shown in FIG. 14, a non-contact development type developing device D using a one-component magnetic toner is widely known. . The cylindrical developing sleeve 3a is used as the developer carrying member, and the toner regulating means 4d is configured by having the supporting member 4d1 cantilever the toner regulating member 4d2. Charge regulation by developer layer regulation and frictional charging is performed by bringing the toner regulating member 4d2 into contact with the developing sleeve 3a. The developer is supplied to the developing sleeve 3a by a magnetic force by providing a magnet 7 in the developing sleeve 3a. Further, a DC bias and an AC bias are applied between the developing sleeve 3a and the photosensitive drum 1, and development is performed in a non-contact manner.

In this method, even if there is a large amount of toner with insufficient chargeability on the developing sleeve 3a, the magnetic toner is arranged near the developing portion, thereby preventing the toner from being unnecessarily developed. For this reason, the charge amount of the developer on the developing sleeve 3a may be set relatively low, and the toner regulating member 4d2 uses a rubber plate having a low contact pressure in consideration of contact stability. Has been proposed (see, for example, Patent Document 1).
JP-A-2-25866

  As described in the above-mentioned Patent Document 1, it is difficult to reduce the size of a blade-shaped toner regulating member that cantilever-supports a conventional thin elastic member and abuts the abdominal surface of the opposite portion against the developing roller. .

  When the toner regulating member is downsized, the distance from the fulcrum supporting the thin plate to the contact point with the developing roller, that is, the free length is shortened. As a result, the spring constant of the contact pressure increases, and the contact pressure changes greatly even if the setting position of the toner regulating member slightly changes. Therefore, it is difficult to obtain a stable contact pressure. In addition, high-precision assembly is required.

  Further, when the free length of the thin elastic member (toner regulating member) is shortened, it is likely to be affected by adhesion unevenness in the cantilever support portion, and it is difficult to apply a uniform contact pressure in the longitudinal direction. As a result, it becomes more difficult to reduce the size.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device that can be positioned easily and can be positioned at the same time as the toner regulating member is stably held by the support member even when the developer carrying member is not incorporated. To provide a cartridge and an image forming apparatus.

  Another object of the present invention is to suppress the transmission of undulations to the contact portion between the developer carrying member and the toner regulating member even when undulations occur when fixedly supported by adhesion or the like. It is an object of the present invention to provide a developing device, a cartridge, and an image forming apparatus that can suppress the above-described problem.

  Another object of the present invention is to provide a developing device, a cartridge, and an image forming apparatus that can be reduced in size easily because stable contact can be performed without being easily assembled. It is.

The above object is achieved by the developing device, cartridge and image forming apparatus according to the present invention. In summary, according to the first aspect of the present invention, in order to develop an electrostatic latent image formed on an image carrier, a developer carrier carrying a developer and a carrier carried on the developer carrier. In a developing device having a developer amount regulating means for regulating the amount of the developed developer,
The developer amount regulating means has a sheet-like regulating member that contacts the developer carrying member, and a support member that supports the regulating member,
The sheet-shaped regulating member is
A first abutting portion which is one end side in the short direction of the regulating member and is supported by the supporting member on the downstream side in the moving direction of the developer carrier;
A second contact portion supported by the support member on the other end side in the short direction of the regulating member;
A third contact portion that contacts the developer carrier between the first contact portion and the second contact portion in the short direction of the restriction member;
Have
The first contact portion is
Having a first first flat surface portion of the regulating member and a first end surface portion intersecting the flat surface portion;
The first plane portion is
Elastic force generated when the regulating member is bent so that the lateral direction is curved over the longitudinal direction and / or elastic force generated when the third contact portion is pressed against the developer carrier. Is supported in contact with the support member,
The first end surface portion is
Due to the force received from the developer carrier by the third abutment portion being pressed against the developer carrier, the third abutment portion is supported by being in contact with the support member,
The second contact portion is
A planar second flat surface portion of the regulating member;
An angle formed by a perpendicular T1 perpendicular to the symmetry line of the first plane portion and the second plane portion and a straight line M1 passing through the first plane portion is α, and the perpendicular T1 is the moving direction of the developer carrier. Is positive, and the straight line M1 passing through the first plane portion is positive in the direction away from the surface of the developer carrier,
In a state where the surface of the developer carrying member and the regulating member are in contact with each other, an angle formed by a tangent line T2 formed by the developer carrying member and the regulating member coming into contact with a straight line M1 passing through the first plane portion. β and the tangent T2 is positive when the direction of movement of the developer carrier is positive.
The relationship between the angle α and the angle β is
30 ° ≦ β <α <90 ° (1)
The filling,
The third abutting portion abuts on the surface of the developer carrying member with the curvature deformed from the curvature of the bent regulation member in a state in which the developer carrying member does not abut,
A developing device is provided.

  According to a second aspect of the present invention, there is provided a cartridge characterized by having at least the developing device having the above-described configuration and being detachable from the image forming apparatus.

  According to a third aspect of the present invention, there is provided an image carrier on which an electrostatic image is formed, and a developing device for developing the electrostatic image formed on the image carrier. Is provided with an image forming apparatus characterized by being a developing device having the above-described configuration.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus characterized in that the cartridge having the above-described configuration is detachable.

The present invention is effective in the following points.
(1) Even in a state where the developer carrier is not incorporated, the sheet-like regulating member (flexible sheet member) can be stably held by the support member and can be positioned, and assembly is easy. Therefore, miniaturization can be easily achieved. Furthermore,
(2) Even if undulation or the like occurs when fixedly supported by adhesion or the like, the axis of the developer carrying body is suppressed in order to prevent the undulation from being transmitted to the contact portion between the developer carrying body and the flexible sheet member. The density unevenness in the longitudinal direction is remarkably suppressed. Also,
(3) Since stable contact can be performed without being easy to assemble, downsizing can be easily performed.

  Hereinafter, a developing device, a cartridge, and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus using the developing device according to the first embodiment of the present invention, and FIG. 2 is a detailed configuration diagram of the developing device.

  That is, the developing device of this embodiment is a contact developing system using a developing roller having an elastic layer.

  In the first embodiment, the image forming apparatus 100 is a full color laser printer using an electrophotographic process. The overall schematic configuration of the image forming apparatus 100 in the present embodiment will be described below.

  In the present embodiment, the image forming apparatus 100 includes a plurality of process cartridges B, each of which forms an image forming unit, that is, four (yellow (Y), magenta (M), cyan (C), and black (K). A process cartridge B (By, Bm, Bc, Bk) is provided. In the present embodiment, the four process cartridges B are arranged side by side in the vertical direction, but the present invention is not limited to this.

  Each process cartridge B has the same configuration and includes a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 (1y, 1m, 1c, 1k) as an image carrier. In this embodiment, a charging device 2 (2y, 2m, 2c, 2k), an exposure device 10 (10y, 10m, 10c, 10k), and a developing device D (Dy, Dm, Dc, Dk) are disposed around the photosensitive drum 1. A cleaning device C (Cy, Cm, Cc, Ck) is arranged. The developing device D and the cleaning device C are integrated as a unit with the photosensitive drum 1, constitutes a process cartridge, and can be attached to and detached from the image forming apparatus main body 100A by a mounting means (not shown).

  The toner images formed by the process cartridges B for the respective colors are transferred onto an intermediate transfer belt 20A as an intermediate transfer member provided in the transfer device 20, thereby forming a full color toner image. Details of the image forming process on each process cartridge B will be described later.

  The toner images formed on the photosensitive drums 1 by the process cartridges B of the respective colors are transferred by primary transfer rollers 22y, 22m, 22c, and 22k provided at positions facing the photosensitive drums 1 of the respective colors with the intermediate transfer belt 20A interposed therebetween. The image is transferred onto the intermediate transfer belt 20A. The four color toner images are collectively transferred onto the recording paper P by the secondary transfer roller 23 provided on the downstream side in the moving direction of the intermediate transfer belt 20A. The untransferred toner on the intermediate transfer belt 20A is collected by the intermediate transfer belt cleaner 21.

  The recording paper P is stacked in a cassette 24 at the bottom of the image forming apparatus 100, and is conveyed by a paper feed roller 25 together with a request for a printing operation, and is formed on the intermediate transfer belt 20A at the position of the secondary transfer roller 23. The transferred toner image is transferred to the recording paper P.

  Thereafter, the toner image on the recording paper P is heated and fixed on the recording paper P by the fixing unit 26, and is discharged to the outside of the image forming apparatus through the paper discharge unit 27.

  In the image forming apparatus 100 of the present embodiment, an upper unit that is a process cartridge B for each of four colors, a transfer unit that is a transfer apparatus 20 including an intermediate transfer belt 20A, a recording sheet, and the like are stored. The lower unit including the cassette 24 can be separated from the image forming apparatus main body 100A. Therefore, in the jam processing such as a paper jam, the upper unit and the lower unit are opened, and further, the upper unit is removed to easily perform the jam processing.

  In the image forming apparatus 100 according to the present embodiment, the life of the process cartridge B considering the toner capacity and the like is set to be equivalent to 4000 sheets in terms of 5% A4 paper printing rate.

  Next, a more detailed configuration of the process cartridge B constituting the image forming unit in the image forming apparatus 100 and the image forming process will be described with reference to FIG.

  As described above, the four process cartridges B (By, Bm, Bc, Bk) installed in parallel in the vertical direction have the same configuration. Therefore, in FIG. 2, the process cartridge and its constituent members are denoted by reference numerals. The figure is shown generically without a subscript.

  As the photosensitive drum 1 which is the center of the image forming process, an organic photosensitive drum 1 in which an outer peripheral surface of an aluminum cylinder is coated with a functional undercoat layer, a carrier generation layer, and a carrier transfer layer in this order is used. In the image forming process, the photosensitive drum 1 is driven in the direction of arrow a in the figure at a predetermined speed.

  A charging roller 2 as a charging device is driven to rotate in the direction of an arrow b by bringing a roller portion 2 a of conductive rubber into pressure contact with the photosensitive drum 1. Here, a direct current voltage of −1100 V is applied to the core 2b of the charging roller 2 with respect to the photosensitive drum 1 as a charging step, and the surface potential of the photosensitive drum 1 due to the electric charge induced thereby is A uniform dark potential (Vd) of −550 V is formed.

  The spot pattern of the laser light emitted corresponding to the image data by the scanner unit 10 as an exposure device on the uniform surface charge distribution surface is a photosensitive drum 1 as indicated by an arrow L in FIG. To expose. The exposed portion of the photosensitive drum 1 loses its surface charge due to carriers from the carrier generation layer, and the potential decreases. As a result, an electrostatic image (electrostatic latent image) is formed on the photosensitive drum 1 with the bright portion potential Vl = −100 V at the exposed portion and the dark portion potential Vd = −550 V at the unexposed portion.

  The electrostatic latent image is developed by a developing device D having a toner coat layer formed on a developing roller 3 as a developer carrying member carrying toner as a developer having a predetermined coating amount and charge amount. Although a method for forming the toner layer will be described later, the developing roller 3 rotates in the forward direction with respect to the rotation direction of the photosensitive drum 1 as indicated by an arrow c while contacting the photosensitive drum 1. In the present embodiment, a DC bias voltage of −350 V is applied to the developing roller 3, and the negatively charged toner due to frictional charging is transferred from the potential difference to the bright portion potential portion at the developing portion contacting the photosensitive drum 1. Only fly to make the electrostatic latent image a real image. That is, the charging polarity of the toner and the polarity of the electrostatic latent image are the same, and reversal development is performed.

  The intermediate transfer belt 20 </ b> A that contacts the photosensitive drum 1 of each process cartridge B is pressed against the photosensitive drum 1 by a primary transfer roller 22 (22 y, 22 m, 22 c, 22 k) facing the photosensitive drum 1. Further, a DC voltage is applied to the primary transfer roller 22, and an electric field is formed between the primary transfer roller 22 and the photosensitive drum 1. As a result, the toner image formed on the photosensitive drum 1 is transferred from the photosensitive drum 1 to the intermediate transfer belt 20A under the force of the electric field in the pressure contact area. On the other hand, the untransferred toner remaining on the photosensitive drum 1 without being transferred to the intermediate transfer belt 20A is scraped off from the drum surface by the urethane rubber cleaning blade 6 installed in the cleaning device C, and is then removed from the cleaning device C. It is stored in.

  Details of the developing device according to the first embodiment will be described below.

  FIG. 3 shows a developing device D to which the developer amount regulating means 4 configured according to Example 1 described later is applied in the present embodiment.

  The developing device D includes a developing container T that contains a non-magnetic one-component developer, and a developing roller 3 that is a developer carrying member that rotates in the forward direction c while being in contact with the photosensitive drum 1. Further, the developing device D includes a supply roller 5 that rotates in the reverse direction d while being in contact with the developing roller 3. Further, a developer amount regulating means 4 that abuts against the developing roller 3 at a position downstream of the supply roller 5 in the rotation direction of the developing roller 3 to regulate the developer amount on the developing roller 3, and the toner in the developing container T. The stirring member 11 which stirs is provided.

Here, in this embodiment, the developing roller 3 uses a 12 mm diameter elastic roller in which a conductive elastic layer 3b is formed with a thickness of 3 mm on a core metal 3a having an outer diameter of 6 mm. Silicone rubber having a volume resistance of 10 ⁶ Ωm was used. The elastic roller surface layer may be provided with a coat layer having a function of imparting charge to the developer. In the present embodiment, the elastic layer 3b has a hardness of 45 ° according to JIS-A and the developing roller 3 has a surface roughness of the particle size of the toner to be used in order to stably and elastically contact the photosensitive drum 1. However, the 10-point average roughness Rz is preferably 3 μm to 15 μm. If the toner particle size to be used is 6 μm in terms of the average volume particle size, it is preferable to use a 10-point average roughness Rz of 5 μm to 12 μm. The ten-point average roughness Rz was defined according to JIS B0601, and a surface roughness tester “SE-30H” manufactured by Kosaka Laboratory was used for measurement.

  Further, in this embodiment, the supply roller 5 has an outer diameter in which a polyurethane foam (elastic foam layer) 5b having a foamed skeleton structure and a relatively low hardness is formed on a core metal 5a having an outer diameter of 5 mm with a thickness of 5.5 mm. A 16 mm elastic sponge roller was used. The supply roller 5 is made of a foam having a continuous foaming property, so that the supply roller 5 contacts the developing roller 3 without applying excessive pressure, and at the time of supplying toner to the developing roller 3 and developing with moderate irregularities on the surface of the foam. The residual toner is removed without being consumed. The scraping property of the cell structure is not limited to urethane foam, and rubber or the like obtained by foaming silicone rubber or ethylene propylene diene rubber (EPDM rubber) can be used.

  A developer that contacts the developing roller 3 on the downstream side of the contact surface between the supply roller 5 and the developing roller 3 with respect to the rotation direction c of the developing roller 3 and regulates the amount of developer carried on the developing roller 3. A quantity regulating means (that is, toner regulating means) 4 is provided. The toner regulating unit 4 includes a developer amount regulating member (that is, a toner regulating member) 40 that contacts the developing roller 3, and a support member 42 that supports the toner regulating member 40.

  The toner regulating means 4 is intended to control the toner on the developing roller 3 to a predetermined coating amount and a predetermined charge amount suitable for development on the photosensitive drum 1. The toner regulating means 4 will be described in detail in each example and comparative example described later.

(Example and comparative example in Embodiment 1)
Hereinafter, in order to clarify the advantageous effects of the present invention in the first embodiment, examples of the first embodiment and comparative examples thereof will be described.

Example 1
With reference to FIGS. 4A to 4D, the developer amount regulating means of this embodiment, that is, the toner regulating means 4 will be described. As described above, the toner regulating unit 4 includes the flexible sheet member 40 that is a sheet-like regulating member, and the support member 42 that supports the flexible sheet member 40.

  FIG. 4D shows a support member 42 that holds the flexible sheet member 40. The flexible sheet support member 42 is a concave inner wall surface for supporting the flexible sheet member 40, that is, first and second side surface support portions 43a, 43b, which are substantially inverted U-shaped, and A support portion (inner wall surface) 43 configured by the bottom surface support portion 43c is provided.

  FIG. 4C shows a state before the toner regulating means 4 of this embodiment, that is, the flexible sheet member 40 is brought into contact with the developing roller 3.

  In FIG. 4A, the flexible sheet member 40 includes a first end 40A and a second end 40B supported by the support member 42, and a first end 40A and a second end 40B. A curved portion 40 </ b> C that is provided in the middle and is curved in the short-side direction over the longitudinal direction and comes into contact with the developing roller 3 is provided.

  More specifically, the first end portion 40A and the first side surface support portion 43a of the support member 42 located on the downstream side with respect to the developing roller rotation direction, which is one end side in the short side direction of the flexible sheet member 40. A first contact portion 47 that contacts the bottom surface support portion 43c is formed. The first contact portion 47 intersects the first flat surface portion 47a, which is in contact with the side surface support portion 43a of the support member 42 on the surface of the flexible sheet member 40, and the first flat portion 47a. It is comprised by the 1st end surface part 47b contact | abutted to the bottom face support part 43c.

  The second end portion 40B is formed on the side surface support portion 43b and the bottom surface support portion 43c of the support member 42 positioned on the upstream side with respect to the developing roller rotation direction, which is the other end side in the short direction of the flexible sheet member 40. A second abutting portion 48 that abuts is formed. Similarly to the first contact portion 47, the second contact portion 48 includes a flat second plane portion 48 a that contacts the side surface support portion 43 b of the support member 42 on the surface of the flexible sheet member 40, and The second end surface portion 48b intersects with the two flat surface portions 48a and contacts the bottom surface support portion 43c of the support member 42.

  Next, as shown in FIG. 4C, the angle formed by the perpendicular T1 perpendicular to the symmetry line L1 between the first plane part 47a and the second plane part 48a, and the straight line M1 passing through the first plane part 47a. Let α be.

  Here, the positive direction of the perpendicular T1 is defined as the downstream direction of the developing roller rotation direction, and the positive direction of the straight line M1 passing through the first flat portion 47a is defined as the direction away from the developing roller 3.

  The angle α is a value determined by the positional relationship between the first plane portion 47a and the second plane portion 48a. In the present embodiment, the angle α is set to 75 ° (<90 °). In FIG. 5, the relationship of the angle α indicates (a) α <90 °, (b) α = 90 °, and (c) α> 90 °.

  In the case of α <90 ° shown in FIG. 5A, the interval between the first flat surface portion 47 a and the second flat surface portion 48 a is widened toward the bottom surface support portion 43 c of the support member 42. On the other hand, as shown in FIG. 5C, when α> 90 °, it means that the distance between the first flat surface portion 47a and the second flat surface portion 48a decreases toward the bottom surface support portion 43c of the support member 42. As shown in FIG. 5B, when α = 90 °, it means that the first plane portion 47a and the second plane portion 48a are parallel.

  In the present embodiment, the flexible sheet member 40 is curved in the lateral direction over the length so that the first flat surface portion 47a and the second flat surface portion 48a abut against the inner wall surface support portion 43 of the concave portion of the support member 42. Is bent to do. Therefore, the first and second side surface support portions of the support member 42 in which the first flat surface portion 47a and the second flat surface portion 48a are formed in a U-shape by the elastic force acting by bending the flexible sheet member 40. It reliably contacts the inner surfaces of 43a and 43b. Thereby, even when the developing roller is not in contact, it can be stably held. Further, the first abutting portion 47 and the second abutting portion 48 are supported by non-adhesion, and can be stably held even when the developing roller 3 is not in contact by setting the angle α <90 °. And easy assemblability can be obtained.

  The reason will be described below with reference to FIG.

  First, the first flat surface portion 47a can hold the flexible sheet member 40 stably by being in pressure contact with the concave inner wall surface 43 of the sheet support portion 43a of the sheet support member 42. The reason why the pressure force is applied is that the flexible sheet member 40 is restored in the short direction over the longitudinal direction, that is, the restoring force (elastic force) F-1 (FIG. This is because a)) acts. In order to cause the restoring force F-1 to act reliably, the first flat portion 47a is formed as a flat surface. Furthermore, simultaneously with the restoring force F-1, a reaction force E-1 acts on the flexible sheet member 40 from the support member 42 as shown in FIG.

  Here, the reaction force E-1 is decomposed into a component Et that is perpendicular to the component Eh that is parallel to the straight line M2 that passes through the second plane part 48a. The parallel component Eh is applied with a force in the direction of the bottom surface support portion 43 c of the support member 42, that is, in the direction in which the support member 42 is incorporated. Even when the developing roller 3 is not in contact, the flexible sheet member 40 is less likely to be detached. In addition, when the Eh force is applied, the first end surface portion 47 b can easily come into contact with the bottom surface support portion 43 c of the support member 42. That is, even when the developing roller 3 is not in contact, the positioning can be performed stably, so that more stable assemblability can be obtained.

  Similarly to the first contact portion 47, the second contact portion 48 works in the direction in which the second contact portion 48 is incorporated into the support member 42, so that more stable retention can be obtained.

  Next, the state of the curved portion 40C where the flexible sheet member 40 and the developing roller 3 abut will be described with reference to FIGS. 4 (a) and 4 (b).

  First, FIG. 4B shows a state where the flexible sheet member 40 and the developing roller are in contact with each other. A point R in FIG. 4B is the center of curvature of the curvature portion (curved portion 40C) generated when the flexible sheet member 40 is curved in the short direction. An angle formed between a tangent line T2 at a contact point P formed by the developing roller 3 and the flexible sheet member 40 and a straight line M1 passing through the first flat portion 47a is β. In this example, the angle β was set to 60 °, and β <α <90 ° was set.

  Here, in order to clarify the relationship of β <α, consider a state where the developing roller 3 and the flexible sheet member 40 are in contact with each other as shown in FIG. In this case, the perpendicular line T1 with respect to the symmetry line L1 and the tangent line T2 at the point P coincide with each other. That is, in the state of α = β, the contact P is formed on the symmetry line L1. That is, in order to set α = β, highly accurate assembly is required.

  On the other hand, as shown in FIG. 4B, a state where the developing roller 3 and the flexible sheet member 40 are in contact with each other when β <α is considered.

  In the relationship of β <α, the tangent line T2 is formed so as to approach M1. That is, in the case of β <α, it means that the flexible sheet member 40 contacts the developing roller 3 on the downstream side in the developing roller rotation direction with respect to the symmetry line L1 in the short direction.

  That is, by setting β <α, it is possible to obtain a simple assembling property because a highly accurate assembling property is not required as compared with the case where α = β.

  Next, from this state, as shown in FIG. 4A, the curved portion 40C and the development are developed by pushing the developing roller 3 so that the curved portion 40C of the flexible sheet member 40 is deformed along the developing roller 3. A contact portion, that is, a third contact portion 46 is formed between the roller 3 and the roller 3. That is, it deform | transforms so that the volume of the hollow part 8 inside the flexible sheet | seat member 40 may reduce. At this time, the direction (X) for pushing the developing roller 3 was set to a direction perpendicular to the tangent line T2. β <α <90 °, and the flexible sheet member 40 is deformed by the developing roller 3 to form the third contact portion 46, so that the contact with the developing roller 3 can be stably performed. .

  The reason is described below.

  First, in the third contact portion 46, the developing roller 3 is pushed into the curved portion 40C to such an extent that the flexible sheet member 40 is deformed along the developing roller 3. Due to the elastic force generated by the pressing of the developing roller 3, the first end surface portion 47 b of the first contact portion 47 and the second end surface portion 48 b of the second contact portion 48 become the bottom surface of the flexible sheet support member 42. It is possible to reliably contact the bottom surface 43 of the concave portion inner wall of the support portion 43c and to perform positioning at a predetermined position more stably. In addition, since the contact width (region of the third contact portion 46) where the developing roller 3 and the flexible sheet member 40 contact each other is sufficiently obtained, a stable contact pressure can be obtained.

  In this embodiment, as the flexible sheet member 40, urethane rubber having a hardness of 70 ° in JIS-A is used. In this embodiment, the toner regulating means 4 is formed by receiving the sheet-like flexible sheet member 40 having a thickness of 0.5 mm by the concave portion 43 of the flexible sheet support member 42.

  Further, as shown in FIG. 4 (d), in the present embodiment, the point I where the first flat surface portion 47a and the first end surface portion 47b intersect in the first and second contact portions 47, 48, the first flat surface portion. Assuming that point J intersects 48a and the first end surface portion 48b, the distance between point I and point J is 6.0 mm. That is, the distance 6.0 mm is a distance on the inner surface 43 between the both side surface support portions 43 a and 43 b of the support member 42.

  In the present embodiment, the flexible sheet member 40 uses urethane rubber, but the same effect can be obtained by using a rubber elastic body such as silicone rubber or NBR rubber. The contact condition between the toner regulating means 4 and the developing roller 3 at this time is such that the pushing amount, which is a virtual overlap amount between the tip position of the flexible sheet member 40 and the surface of the developing roller 3, is 0.5 mm. As a result, the set value of the contact pressure between the toner regulating means 4 and the developing roller 3 (linear pressure in the generatrix direction of the developing roller) is set to 20 kPa.

  The contact pressure is generally measured using a thin-film sheet-shaped pressure sensor (for example, prescale; manufactured by Fuji Photo Film Co., Ltd.). Low and difficult to measure with common pressure sensors. Therefore, the contact pressure is measured by stacking three H materials of SUS304 steel strip having a thickness of 20 μm and inserting them into the contact portion between the flexible sheet member 40 and the developing roller 3, and tangent to the contact surface. Pull the center thin plate in the direction with a spring balance, and measure the pulling force at that time. And it calculated | required from the calibration value and contact | abutting width | variety by drawing pressure measurement when a known load is applied to this pressure measuring jig.

Example 2
FIG. 6A shows the toner regulating means 4 of this embodiment. The toner regulating means 4 in the present embodiment is basically configured similarly to the first embodiment (FIG. 4). The only difference is that the flat portion 48a of the flexible sheet member 40 on the upstream side in the rotation direction of the developing roller 3 is fixedly supported on the support member 42 by bonding or the like.

Comparative Example 1
The toner regulating means of Comparative Example 1 will be described.

  The developing device D of Comparative Example 1 shown in FIG. 9 includes a blade-shaped toner regulating member 4c2 as the toner regulating means 4. The feature is that the thin plate elastic member 4c2 as a toner regulating member is supported in a cantilever manner, and the abdominal surface of the thin plate elastic member 4c2 is in contact with the developing roller 3.

  The difference between Comparative Example 1 and Example 1 is that, in addition to the shape, Comparative Example 1 is different from Example 1 in that the contact width between the toner regulating member 4c2 and the developing roller 3 (N ) Is small.

Comparative Example 2
The toner regulating means of Comparative Example 2 will be described.

  The toner restricting means 4 of Comparative Example 2 shown in FIG. 10 (a) has a developing device frame 43d by curving a plate-like elastic body 40d made of rubber or the like as a toner restricting member so as to protrude toward the developing roller 3d. Both ends are fixed to a fixing portion 49d provided in The contact with the developing roller 3d is made by a curved surface that is convexly curved.

  Further, the surface of the developing roller 3d is in contact with the curved surface of the developing roller 3d in a state where the developing roller 3d is not in contact with the surface of the developing roller 3d.

  Here, the difference from the first embodiment is that the first contact portion 47 and the second contact portion 48 are bonded and fixed to the fixing portion 49d. Furthermore, the angle α = 90 °.

Comparative Example 3
The toner regulating means of Comparative Example 3 will be described.

  The toner regulating means 4 of Comparative Example 3 shown in FIG. 10B has a fixing portion 43e on the side of the hollow portion 8 generated when the flexible sheet member 40 as the toner regulating member is curved and formed. . Further, the flexible sheet member 40 is bonded and fixed to the fixing portion 43e.

  Furthermore, the contact width (N) between the developing roller 3 and the flexible sheet member 40 is large.

  When the straight line M1 passing through the first contact portion is taken as shown in FIG. 10B, α = 90 degrees and β = 45 degrees.

Comparative Example 4
The toner regulating means 4 in the comparative example 4 is basically configured in the same manner as in the second embodiment, except that α = β = 90 ° is set as shown in FIG. Different.

Comparative Example 5
The toner regulating means 4 in the comparative example 5 has basically the same configuration as that of the second embodiment, but is set to α = 100 ° and β = 80 ° as shown in FIG. Is different.

Comparative Example 6
The toner regulating means 4 in the comparative example 6 is basically configured in the same manner as in the first embodiment, but differs in that the first contact portion 47, particularly the first flat surface portion 47a is bonded and fixed. .

(Superiority over conventional technology)
First, an advantage over Comparative Example 1 including a blade-shaped toner regulating member according to the prior art will be described. Specifically, Example 1 and Comparative Example 1 are compared.

  The comparative example 1 (FIG. 9) includes a blade-shaped toner regulating member 4c2, which is a conventional technique, as the toner regulating means 4c. The feature is that the thin plate elastic member 4c2 as a toner regulating member is supported in a cantilever manner, and the abdominal surface of the thin plate elastic member 4c2 is in contact with the developing roller 3. In the fixed portion between the support portion 4c1 and the thin plate elastic member 4c2 that are supported in a cantilever manner, waviness or the like may occur in the longitudinal direction due to uneven adhesion. In the toner restricting member configuration of Comparative Example 1, since the contact width N between the toner restricting member 4c2 and the developing roller 3 is small, the contact pressure tends to fluctuate in the longitudinal direction according to the undulation.

  Next, problems in miniaturization will be described.

  Since Comparative Example 1 supports the thin plate elastic member 4c2 in a cantilever manner, the amount of change in the contact pressure against the toner regulating member 4c2 increases with an increase in the pushing amount of the developing roller 3. Conventionally, in order to reduce this change, it is necessary to secure a sufficiently large distance from the fulcrum supporting the thin plate to the contact point with the developing roller 3, that is, the free length, and to reduce the spring constant. However, at the time of downsizing, since the free length is shortened, the spring constant is increased. As a result, even if the setting position of the toner regulating member is slightly changed, the contact pressure is greatly changed. That is, it becomes difficult to stably obtain a predetermined contact pressure when downsizing.

  Furthermore, since the spring constant increases, the influence of the longitudinal contact pressure unevenness due to the above-described waviness in the longitudinal direction increases, and the longitudinal unevenness of the image density is likely to occur significantly. That is, at the time of downsizing, in order to stably obtain a desired contact pressure over the longitudinal direction, a highly accurate assembly property is required.

  In addition, it is more difficult to reduce the size of the image forming apparatus 100 of a system in which four color process cartridges as shown in FIG.

  This is because the position of the toner regulating means 4c greatly affects the interval between adjacent process cartridges. Specifically, it is needless to say that an arrangement configuration that does not interfere with the charging, exposure, and development processes on the photosensitive drum is required, and further, due to the influence of stirring, circulation, gravity, and the like accompanying toner conveyance. The developing device is also required to have a high arrangement.

  However, in order to obtain a desired contact pressure in Comparative Example 1, the distance from the fulcrum supporting the thin plate 4c2 to the contact point with the developing roller 3, that is, the free length is secured, and the spring constant is kept small. Is required.

  That is, in addition to the above-described requirement for a high arrangement configuration, there is a higher requirement for securing a free length, which significantly hinders the miniaturization of the color image forming apparatus 100 as shown in FIG.

  On the other hand, in the toner restricting means 4 of the present invention, the flexible sheet member 40 is in contact with the recess 43 of the flexible sheet support member 42 incorporated in the developing container. It is bent and attached so as to bend in the short direction. As a result, the flexible sheet member 40 is formed with a curved portion 40 </ b> C along the longitudinal direction of the flexible sheet member 40.

  In the flexible sheet member 40, the first contact portion flat surface portion 47 a is in contact with the concave inner wall 43 of the side surface support portion 43 a of the flexible sheet support member 42. Therefore, the restoring force F-1 which tries to return from the attitude | position bent so that the transversal direction may bend over the longitudinal direction is fully acting. Accordingly, since the developing roller 3 can be stably maintained even in a state where the developing roller 3 is not in contact, it can be easily assembled.

  Further, the flexible sheet member 40 is located on the inner side of the flexible sheet member 40 formed by the flexible sheet member 40 at the third contact portion 46 of the curved portion 40 </ b> C that is a contact portion with the developing roller 3. The hollow portion 8 is deformed along the peripheral surface of the developing roller so that the volume of the hollow portion 8 is reduced. Therefore, the contact width between the flexible sheet member 40 and the developing roller 3, that is, the contact width N can be secured sufficiently large. Therefore, the contact between the toner regulating means 4 and the developing roller 3 can be stably performed.

  That is, the spring constant of the contact pressure can be obtained stably by adjusting the size of the hollow portion 8 and the thickness and hardness of the flexible sheet member 40. In addition, since a predetermined free length is not required unlike the regulating member 4c2 of Comparative Example 1, a desired contact pressure can be easily obtained.

  Further, when the developing roller 3 is pushed into the flexible sheet member 40, the end surface 47b of the first contact portion 47 reliably contacts the concave inner wall surface 43 of the bottom surface support portion 43c of the sheet support member 42, Positioning is regulated at a predetermined position. That is, the width of the flexible sheet member 40 in the short direction, the width of the concave portion 43 of the sheet supporting member 42, the distance between the developing roller 3 and the concave inner wall surface 43 of the bottom surface supporting portion 43c of the sheet supporting member 42, If it is determined, the contact position is uniquely determined. Therefore, it can be easily assembled without requiring high-precision adjustment. As described above, in the toner regulating means 4 of the present invention, since a desired contact pressure can be stably obtained with a simple configuration, uneven contact pressure in the longitudinal direction is unlikely to occur. As a result, it is possible to remarkably suppress the occurrence of longitudinal density unevenness of the image density that is likely to occur in the regulating means 4c (FIG. 9) of Comparative Example 1.

  As described above, in this embodiment, it is possible to easily obtain a desired contact pressure without requiring highly accurate assembly. In particular, in Example 1, the contact does not become extremely unstable due to the downsizing as in Comparative Example 1, that is, the free length is shortened. Therefore, even when downsizing, a desired contact pressure can be easily obtained without requiring highly accurate assembly. Furthermore, even when downsizing, the desired contact pressure can be stably maintained over the length, and the longitudinal unevenness of the image density is remarkably suppressed.

  In addition, in the image forming apparatus 100 of the type in which the four color process cartridges as shown in FIG. It is very advantageous for conversion.

Evaluation Method for Each Example and Comparative Example Hereinafter, image evaluation for examining the difference between the example of the present invention and the comparative example will be described.

(A) Evaluation of holding stability of toner regulating member without developing roller Before incorporating developing roller 3, the holding stability of toner regulating member (flexible sheet member 40) was evaluated according to the following criteria.
X: The state before incorporating the developing roller is unstable and easily detached.
(Triangle | delta): Although the state before incorporating a developing roller is stable, positioning is unstable.
○: The state before the development roller is assembled is stable, and the positioning is stable.

(B) Evaluation of contact stability of toner restricting member when developing roller is present After contact of the developing roller with the toner restricting member, contact stability of the toner restricting member during rotation of the developing roller was evaluated according to the following criteria.
XX: The attitude of the toner regulating member (flexible sheet member) is deformed when the developing roller rotates. Thereafter, the first contact portion is detached from the support member.
X: The posture of the flexible sheet member is deformed when the developing roller rotates. Thereafter, when the developing roller is stopped, the posture of the flexible sheet member does not return.
Δ: While the developing roller rotates, the posture of the flexible sheet member is deformed, but thereafter, the posture of the flexible sheet member returns to the original state when the developing roller is stopped.
A: The posture of the flexible sheet member is not deformed regardless of the rotation of the developing roller.
Here, the deformation of the posture of the flexible sheet member was visually evaluated.

(C) Longitudinal density unevenness after durability Image evaluation outputs a solid image that prints black on the entire surface, and extends in the longitudinal direction (laser main scanning direction), that is, in the direction perpendicular to the longitudinal axis direction of the developing roller. The presence or absence of vertical strip-like density unevenness was evaluated visually.
X: Five or more strip-shaped density irregularities are recognized.
(Triangle | delta): A strip | belt-shaped density | concentration unevenness is recognized by two or more and less than five.
◯: Strip density unevenness is recognized with one or less.
A: Strip density unevenness cannot be recognized.
Longitudinal density unevenness was evaluated after a 4000-sheet printing test. The printing test was performed by continuously passing a horizontal line of recorded images having an image ratio of 5%.

(D) Evaluation of sheet detachment After the toner on the developing roller is removed, it is brought into contact with a toner regulating member (flexible sheet member), and the holding property of the flexible sheet member to the support member when the developing roller rotates is as follows. It was evaluated with.
X: Evaluated 10 times and detached from the support member once or more.
(Circle): It evaluates 10 times and does not remove | deviate from a support member once.

(Evaluation results)
The evaluation results of Example 2 and Comparative Examples 2 to 4 are shown in Table 1 below.

(Advantage of the comparison technique in the first embodiment)
Next, the superiority of the present invention will be described by comparing Example 1 and Comparative Examples 2 to 4.

(A) Retention evaluation of toner regulating member before incorporation of developing roller First, the assembly stability of the toner regulating member (flexible sheet member 40) will be described by comparing Example 2 with Comparative Examples 4 and 5. .

  The toner regulating member of Comparative Example 5 shown in FIG. 11B is an example in which α = 100 °> 90 °, but the stability is poor before the developing roller 3 is attached.

  The reason for this is that, as shown in FIG. 5C, in Comparative Example 5, the first flat surface portion 47 a of the flexible sheet member 40 receives a repulsive force E from the support member 42. The repulsive force E is generated as a result of the elastic force generated when the flexible sheet member 40 is bent. The repulsive force E is decomposed into a horizontal component Et perpendicular to the straight line M2 passing through the second plane portion 48a and a vertical component Eh parallel to the straight line M2.

  In Comparative Example 5, the vertical component Eh generates a force in a direction away from the support member 42. Therefore, the flexible sheet member 40 is easily detached in a state where the developing roller 3 is not in contact, and stability is lowered.

  On the other hand, the regulating member of Example 2 is an example in which α = 75 ° <90 ° and β = 60 ° <α <90 °, and a repulsive force E-1 as shown in FIG. . The vertical component Eh that is horizontal to the straight line M <b> 2 that passes through the second plane part 48 a is subjected to a force in the direction of being incorporated into the support member 42. Accordingly, in Example 2, the flexible sheet member 40 is unlikely to come off even when the developing roller 3 is not in contact. Further, when the Eh force is applied, the first end surface portion 47b can easily come into contact with the inner surface 43 of the support portion 43c. That is, even when the developing roller 3 is not in contact, the positioning can be performed stably, so that more stable assemblability can be obtained.

  In Comparative Example 4, as shown in FIG. 5 (b), the vertical component Eh of the repulsive force E-1 is remarkably small, so that it is considered difficult to act in the direction in which the repulsive force E-1 is incorporated. Accordingly, since the flexible sheet member 40 is unlikely to be detached from the support member 42 in a state where the developing roller 3 of Comparative Example 4 is not in contact, stable holding is possible. However, since stable contact with the first end surface portion 47b as in the second embodiment cannot be obtained, the assembly stability is inferior to that in the second embodiment.

  In Example 1 and Comparative Example 6, for the same reason as in Example 2, the assembly stability is good when the developing roller is not incorporated.

  As described above, in the sheet regulating means 4 of the present embodiment, the developing roller 3 has an elastic force generated by bending the flexible sheet member 40 at the first abutting portion 47 and the angle α <90 °. The flexible sheet member 40 can be stably held on the support member 42 even in a state where the contact is not made. Further, the flexible sheet member 40 can be positioned.

(B) Contact stability during rotation of developing roller Next, contact stability of the sheet regulating means 4 during rotation of the developing roller will be considered.

  In the second embodiment, as illustrated in FIG. 6, the flexible sheet member 40 is deformed along the developing roller 3 by pushing the developing roller 3. As a result, the abutting width of the third abutting portion 46 that abuts against the developing roller is large. Therefore, the frictional force fa when the developing roller 3 rotates increases. Then, it is difficult to maintain the posture of the flexible sheet member 40, and it is considered that the contact stability is lowered.

  However, the contact of Example 2 is stable. The following two points can be considered as the reason.

  First, in the second embodiment, the first flat portion 47a is supported by the support member 42 by the elastic force generated by the bending of the flexible sheet 40. Second, an angle β = 60 ° (<90 °) between the straight line M1 passing through the first flat surface portion 47a in the first contact portion 47 and the tangent line T2 when the developing roller 3 and the flexible sheet member 40 are in contact with each other. It is to be.

  The detailed reason will be described by comparing Example 2 with Comparative Examples 4 and 6.

  Comparative Example 4 (FIG. 11A) has poor contact stability when the developing roller rotates compared to Example 2. In Comparative Example 4, as shown in FIG. 6C, a straight line M1 passing through the first flat surface portion 47a in the first contact portion 47 and a tangent line T2 in a state where the developing roller 3 and the flexible sheet member 40 are in contact with each other. This is an example in which the angle β = 90 °.

  When the frictional force fa is applied during rotation of the developing roller, a stress fb parallel to the frictional force fa is generated at the point S at the lowest end of the support member wall surface in contact with the first flat portion 47a. As a result, the flexible sheet member 40 is likely to rotate with the S point as a fulcrum, so that the collapse Z occurs. That is, the flexible sheet member 40 is easily deformed, and the contact stability is lowered.

  On the other hand, in Example 2, since the angle β <90 ° is set even when the frictional force fa when the developing roller rotates, it is considered that the deformation of the flexible sheet member 40 hardly occurs. As shown in FIG. 6B, when the frictional force fa is applied, a stress fb in a direction parallel to the frictional force fa is generated at the point S as in the comparative example 4. However, it is considered that the force that the flexible sheet member 40 deforms with the S point as a fulcrum is related to the force in the direction perpendicular to the straight line M1 passing through the first flat portion 47a. Therefore, the stress fb is decomposed into a force fbt parallel to the straight line M1 and a force fbh perpendicular to the straight line M1. Then, fb> fbh is satisfied, and it is considered that the flexible sheet member 40 can be prevented from rotating. Therefore, the contact of Example 2 is more stable than that of Comparative Example 4.

  However, like Comparative Example 6, the contact stability is inferior to that of Example 2 even though the angle β <90 ° is set. The comparative example 6 is different from the second embodiment in that the first flat portion 47a of the first contact portion 47 is fixed by adhesion or the like.

  As shown in FIG. 6B, in Comparative Example 6, when the frictional force fa is applied, the first flat surface portion 47 is fixed, so that the same force fc in the opposite direction to the stress fb is concentrated at the S point. To do.

  As a result, even if the angle β <90 °, the stress fb is large and the vertical component fbh is also large, so that the flexible sheet member 40 is likely to be deformed.

  On the other hand, in Example 2 in which the first flat surface portion 47 is supported by the elastic force generated by the bending of the flexible sheet member 40, it is considered that the stress fb can be suppressed from being concentrated at the S point. It is done.

  More specifically, as shown in FIG. 6A, it is considered that the same stress as the stress fb generated in the comparative example 6 is received by the entire first flat surface portion in the example 2, like fc2. . As a result, since the stress fb2 at the point S is remarkably reduced, it is considered that the posture deformation of the flexible sheet member 40 is suppressed. As a result, the vertical component fb2h is remarkably small, so that it is considered that the flexible sheet member is prevented from falling.

  Moreover, since the other contact examples 2 and 3 also fix the first contact portion 47, it is considered that the stress is concentrated and the flexible sheet member 40 is easily deformed.

  As described above, the sheet regulating means 4 in the present invention is stable in any of the state before the developing roller 3 is assembled, the state in which the developing roller 3 is in contact, and the state in which the developing roller 3 is rotated. It is supported by the support member 42 and can be positioned. Therefore, easy assembly can be obtained. In any state, a desired contact pressure with the developing roller 3 can be stably obtained.

(C) About longitudinal density nonuniformity evaluation result Next, Example 1, 2, and Comparative Examples 2-4 and 6 are compared about longitudinal density nonuniformity evaluation.

  First, the cause of occurrence of longitudinal density unevenness will be considered. Longitudinal density unevenness is likely to occur when the uniformity of the contact pressure in the longitudinal direction is lowered when the flexible sheet member 40 is fixed to the support member 42 by adhesion or the like. In particular, it is considered that it becomes easy to be noticeable as the number of stamps increases.

  In the first embodiment, the first contact portion 47 and the second contact portion 48 are held by the support member by the elastic force generated when the flexible sheet member 40 is bent. Therefore, longitudinal density unevenness hardly occurs and longitudinal density unevenness can be remarkably suppressed.

  In Example 2, although the second contact portion 48 was bonded and fixed, the occurrence of longitudinal density unevenness was suppressed. The reason is described below.

  When the flexible sheet member 40 is held in a U shape and abuts against the developing roller 3, the curved flexible sheet member 40 abuts at the curvature portion 40C as shown in FIG. Stretching n1 occurs on the surface 46 side, and shrinkage m occurs on the surface of the hollow portion 8 surface. Occurrence of this elongation n1 makes it easy to generate the smooth portion v over the length as shown in FIG. For this reason, even if the wavy w as shown in FIG. 8C is generated in the second plane portion 48a, the wavy is gradually relaxed before reaching the smooth portion v due to the generation of the extension n1 of the bending portion 40C, and the smoothness becomes smooth. The wave w is prevented from being transmitted to the part v.

  In addition, in the second embodiment, the angle β <the angle α, that is, the contact is made on the downstream side in the developing roller rotation direction from the symmetry line L1. For this reason, even if the adhesion unevenness on the upstream side occurs, since the upstream wavy w is relaxed and brought into contact with the developing roller on the downstream side of the smooth portion v, the wavy w is more effectively applied to the third abutting portion 46. Suppresses being transmitted to.

  Furthermore, the first contact portion 47 is in contact with the inner surface 43 of the side surface support portion 43a by the elastic force generated by bending the flexible sheet member 40. Therefore, the flexible sheet member 40 can be displaced at the first contact portion 47 so that the wavy w generated by the second contact portion 48 is relaxed. Therefore, in Example 2, it is considered that the longitudinal density unevenness is suppressed even when the second contact portion 48 is bonded and fixed.

  On the other hand, in Comparative Examples 2, 3, and 6, longitudinal density unevenness occurs despite being in contact with the downstream side of the symmetry line L1 with respect to the rotation direction of the developing roller. The reason is considered to be that the first contact portion 47 is fixed.

  As shown in FIG. 8D, when the wavy w1 is generated in the first abutting portion 47 close to the third abutting portion 46, it reaches the third abutting portion 46 without sufficiently relaxing the waving. As a result, it is considered that longitudinal density unevenness occurs.

  Further, in Comparative Example 4, the longitudinal density unevenness is inferior to that in Example 2 although the first contact portion 47 is held by the elastic force generated by the bending of the flexible sheet member 40. The reason is considered to be that β = α. Specifically, it can be considered as follows.

  First, the third contact portion 46 is in contact with the developing roller 3 at a position intersecting with the symmetry line. Then, the wavy w2 generated in the second contact portion 48 (the flat portion 48a) gradually decreases until reaching the flat portion generated by the bending of the flexible sheet member 40. However, since sufficient relaxation cannot be obtained, longitudinal density unevenness tends to occur.

  As described above, the longitudinal density unevenness is remarkably suppressed in the present invention.

  In particular, when the second contact portion 48 is bonded and fixed (Example 2), even if undulation occurs, it is difficult to transmit the undulation to the third contact portion 46, and thus uneven longitudinal density hardly occurs.

(D) Evaluation of detachment of flexible sheet member When the amount of toner decreases, there may occur a situation in which it is difficult to supply toner to a part of the developing roller 3 in the longitudinal direction in the axial direction. Under such circumstances, if the flexible sheet member 40 is detached from the support member 42, it causes toner leakage. In the first embodiment, since the first contact portion 47 and the second contact portion 48 are supported by the elastic force generated when the flexible sheet member 40 is bent, the sheet member 40 is likely to be detached. it is conceivable that. On the other hand, in Example 2 and Comparative Examples 2 to 6, the flexible sheet member 40 did not come off due to at least the second contact portion 48 being fixed.

Relationship between Angle α and Angle β Hereinafter, the superiority of the toner regulating member of the present invention over the range of the angle α and the angle β will be described. Specifically, Examples 2 to 13 and Comparative Examples 4 to 9 will be described.

1) Examples 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
Examples 3 to 13 basically conform to the toner regulating member of Example 2 (FIG. 6), but differ in the following points.

  In FIG. 4 (FIG. 6), the angle α is 88, 88, 46, 40, 35, 70, 60, 84, 50, 85, 70 degrees, and the angle β is 60, 70, 30, 32, 30, 33, 68. 55, 80, 45, 40, 45 degrees.

2) Comparative Examples 7, 8, 9, 10
Comparative Examples 7 to 10 basically conform to the toner regulating member of Example 2 (FIG. 6), but differ in the following points.

  In FIG. 4 (FIG. 6), the angle α is 95, 23, 45, and 43 degrees, and the angle β is 25, 25, 45, and 25 degrees.

Evaluation Method for Each Example and Comparative Example Hereinafter, image evaluation for examining the difference between the present invention and the comparative example will be described.

(A) Evaluation of holding stability of toner regulating member without developing roller Before the developing roller 3 was assembled, the holding stability of the sheet regulating member 40 was evaluated according to the following criteria.
X: The state before incorporating the developing roller is unstable and easily detached.
(Triangle | delta): Although the state before incorporating a developing roller is stable, positioning is unstable.
○: The state before the development roller is assembled is stable, and the positioning is stable.

(B) Evaluation of contact stability of regulating member when developing roller is present Stability of contact of sheet regulating member 40 when developing roller is rotated after developing roller 3 is brought into contact with sheet regulating member (flexible sheet member) 40 Was evaluated according to the following criteria.
X: The posture of the flexible sheet member is deformed when the developing roller rotates. Thereafter, when the developing roller is stopped, the posture of the flexible sheet member does not return.
Δ: While the developing roller rotates, the posture of the flexible sheet member is deformed, but thereafter, the posture of the flexible sheet member returns to the original state when the developing roller is stopped.
A: The posture of the flexible sheet member is not deformed regardless of the rotation of the developing roller.
Here, the deformation of the posture of the flexible sheet member 40 was visually evaluated.

(C) Longitudinal density unevenness evaluation Image evaluation is performed by outputting a solid image on which black is printed on the entire surface, and visually checking whether there is density unevenness in a vertical strip extending in the vertical direction with respect to the longitudinal direction (laser main scanning direction). evaluated.
X: Five or more strip-shaped density irregularities are recognized.
(Triangle | delta): A strip | belt-shaped density | concentration unevenness is recognized by two or more and less than five.
◯: Strip density unevenness is recognized with one or less.
Longitudinal density unevenness was evaluated after a 4000-sheet printing test. The printing test was performed by continuously passing a horizontal line of recorded images having an image ratio of 5%.

(D) Evaluation of generation of agglomerates In image evaluation, a solid image on which black was printed on the entire surface was output, and the output image was evaluated according to the following evaluation criteria.
X: Two or more vertical stripes having a width of 0.2 mm or less are recognized.
A: Less than two vertical stripes with a width of 0.2 mm or less are recognized.
Evaluation of the generation of agglomerates was performed after a 4000-sheet printing test. The printing test was performed by continuously passing a horizontal line of recorded images having an image ratio of 5%.

(Evaluation results of each example and comparative example)
The above-mentioned (A) holding stability, (B) contact stability, (C) longitudinal density unevenness, and (D) toner aggregate generation were evaluated. Table 2 shows the results.

(A) Evaluation of holding stability of flexible sheet member before incorporation of developing roller (FIG. 15)
First, Comparative Example 8 has poor holding stability of the flexible sheet member 40 when the developing roller 3 is not in contact. The reason is considered that the elastic force which acts when the flexible sheet member 40 curves is weak. That is, since the angle α is smaller than 30 °, the amount of bending of the flexible sheet member 40 is small, so that sufficient elastic force for holding cannot be obtained. As a result, it is considered that the retainability of the flexible sheet member 40 is poor in a state where the developing roller 3 is not incorporated.

  On the other hand, in Comparative Example 5 in which the angle α ≧ 30 °, the elastic force works sufficiently, but as described above, the force works in the direction away from the support member 42 in the state where the developing roller is not in contact, so that the flexibility is flexible. The sheet retention stability is poor.

  Also in Comparative Example 4, since no force is generated in the direction in which the flexible sheet member 40 is pushed in when the developing roller 3 is not incorporated, positioning is performed when the developing roller 3 is not incorporated. I can't. As a result, the slight stability is poor.

  In Examples 3 and 4, since the angle α <90 °, a force acts in the direction in which the flexible sheet member 40 is pushed into the support member 42 when the developing roller 3 is not incorporated. As a result, the contact stability is improved. However, Examples 3 and 4 are slightly inferior in stability to Examples 10 and 12. The reason is considered that the force in the direction in which the flexible sheet member 40 is pushed into the support member does not sufficiently work. That is, positioning cannot be performed stably.

  On the other hand, in Examples 10 and 12, since the angle α is set to 85 ° or less, the detachment from the support member can be stably suppressed, and the positioning can also be performed stably.

  That is, the toner regulating means 4 according to the present invention has an angle α of 30 ° ≦ α <90 ° in order to stably hold the flexible sheet member 40 even when the developing roller 3 is not incorporated. In particular, the angle α is more preferably 30 ° ≦ α ≦ 85 °.

(B) Contact stability with developing roller (FIG. 16)
First, Comparative Examples 7, 8, and 10 are inferior in stability to Examples 5, 6, and 7. The reason is considered that the angle β is smaller than 30 °. As shown in FIG. 6, when β is smaller than 30 °, the first flat portion 47 a is in contact with the developing roller 3 in an extremely tilted state. As a result, the elastic force of the flexible sheet member 40 is less likely to act on the developing roller 3, and it becomes difficult to stably obtain a desired contact pressure. On the other hand, in Examples 7, 8, and 10, since the angle β is 30 ° or more, it is considered that a desired contact pressure can be stably obtained.

  That is, the toner regulating means 4 of the present invention can obtain a desired contact pressure by setting β ≧ 30 °.

  In Comparative Example 4, since the angle β = 90 °, as described above, the flexible sheet member 40 is liable to fall down, so that the contact stability when the developing roller rotates is low.

  As described above, in the toner regulating means 4 of the present invention, in order to stabilize the contact when the developing roller rotates, it is preferable that 30 ° ≦ β <90 °.

(C) Longitudinal density unevenness evaluation result (FIG. 17)
Comparative Examples 4 and 9 are more likely to cause longitudinal density unevenness than Examples 7 and 8. The reason is described below.

  As described in the evaluation result of the longitudinal density unevenness, the longitudinal density unevenness is likely to occur when the adhesion unevenness of the second contact portion 48 reaches the third contact portion 46. In Comparative Examples 4 and 9, the relationship between the angle α and the angle β is α = β. In this relationship, the third contact portion 46 contacts the developing roller 3 at a position intersecting with the symmetry line L1. That is, the flat portion formed in the bending portion 40 </ b> C that is generated when the flexible sheet member 40 is bent becomes the third contact portion 46. As a result, it is considered that the unevenness in the longitudinal density occurs due to the contact with the developing roller 3 in a state where the waviness due to the adhesion or the like of the second contact portion 48 cannot be sufficiently relaxed.

  On the other hand, in Examples 7 and 8, the relationship between the angle α and the angle β is such that β <α.

  In this relationship, the third contact portion 46 contacts the developing roller 3 on the downstream side in the rotation direction of the developing roller with respect to the symmetry line L1. Therefore, it is considered that the undulation generated at the second contact portion 48 is sufficiently mitigated at the flat portion formed by the bending portion 40 </ b> C when the flexible sheet member 40 is bent. As a result, the third abutting portion 46 abuts at a downstream position in the developing roller rotation direction in which the undulation is sufficiently relaxed, and therefore, the longitudinal density unevenness is suppressed.

  However, Examples 7 and 8 cause slight longitudinal density unevenness as compared with Examples 9 and 11. In Examples 7 and 8, the relationship between the angle α and the angle β is a relationship of β <α. However, it is considered that slight longitudinal density unevenness is caused because the relationship is not sufficiently separated from the symmetry line L1.

  On the other hand, Examples 9 and 11 have a relationship of β ≦ α−5 °. From this relationship, it is considered that the third contact portion 46 is formed sufficiently downstream from the symmetry line L1. As a result, it is considered that the longitudinal density unevenness is remarkably suppressed.

  As described above, in the toner regulating means of the present invention, in order to suppress longitudinal density unevenness, the relationship between the angle α and the angle β is preferably β <α, and β ≦ α−5 °. More preferred.

(A, B, C) Contact stability comprehensive evaluation (FIG. 18)
18A and 18B show the overall evaluation results of (A) the stability of holding the flexible sheet before assembling the developing roller, (B) the contact stability during rotation of the developing roller, and (C) the longitudinal density unevenness evaluation. That is, the overall advantage of the contact stability of the regulating member in the present invention will be described.

  As can be seen from FIG. 18, in the toner regulating means of the present invention, it is preferable that 30 ° ≦ β <α <90 °, and 30 ° ≦ β ≦ α-5 in order to obtain overall stability. More preferably, it is ° ≦ 85 °.

(D) Evaluation result of toner aggregate (FIG. 19)
FIG. 19 shows the result of toner aggregate evaluation. As can be seen from the figure, when a straight line satisfying β ≦ 2α−60 ° is satisfied, generation of streaks due to toner aggregates was suppressed.

  Here, the relational expression β ≦ 2α−60 ° corresponds to the relationship of γ ≧ 60 when γ in FIG. 4 is used. That is, γ can be regarded as an amount indicating the width of the toner intake port. If γ is smaller than 60 °, the toner is extremely stagnant and it is considered that agglomerates are easily generated.

  From the above, in the present invention, in order to suppress the formation of toner agglomerates, it is more preferable to set the toner intake port γ ≧ 60 °, that is, β ≦ 2α-60 °.

(Embodiment 2)
FIG. 12 is a schematic configuration diagram showing an example of an image forming apparatus using a developing device according to the second embodiment of the present invention, FIG. 12 is a monochrome laser printer main body as the image forming apparatus, and FIG. 13 is the monochrome laser. It is sectional drawing about the developing device used for a printer.

  In this embodiment, the image forming apparatus 100 is a monochrome laser printer using an electrophotographic process. The overall schematic configuration of the image forming apparatus 100 in the present embodiment will be described below.

  In this embodiment, the image forming apparatus 100 includes a process cartridge B that constitutes an image forming unit.

  The process cartridge B includes a drum-shaped electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 1. In this embodiment, a charging device 2, an exposure device 10, a developing device D, and a cleaning device C are disposed around the photosensitive drum 1. The developing device D and the cleaning device C are integrated as a unit with the photosensitive drum 1, constitutes a process cartridge, and is detachable from the image forming apparatus main body 100A by a mounting means (not shown).

  The toner image formed on the photosensitive drum 1 by the process cartridge B is transferred to the recording paper P by the primary transfer roller 22 provided at a position facing the photosensitive drum 1.

  The recording paper P is stacked in a cassette 24 below the image forming apparatus 100, and is conveyed by a paper feed roller 25 when a printing operation is requested. A toner image is transferred to the recording paper P at the position of the primary transfer roller 22. Is done.

  Thereafter, the toner image on the recording paper P is heated and fixed on the recording paper P by the fixing unit 26, and is discharged to the outside of the image forming apparatus through the paper discharge unit 27.

  Each process unit constituting the image forming unit is the same as that described in the first embodiment except for the developing device D. Accordingly, the same reference numerals are assigned to these process means, and the description of the first embodiment is used, and further detailed description is omitted here.

  The developing device D used in the present embodiment is a non-contact developing system using magnetic toner using a metal sleeve 3a.

  That is, in this embodiment, a metal sleeve obtained by coating a conductive resin on the developing sleeve 3a as a developer carrying member is used. Inside the developing sleeve 3a, there is provided a fixed magnet roller (magnetic field generating means) 7 for generating a magnetic field having a predetermined magnetic pole arrangement. The magnetic toner in the developing container is attracted to the surface of the developing sleeve 3 a by the magnetic force with the magnet roller 7. The magnetic toner adhering to the surface of the developing sleeve 3a is conveyed by the rotation of the developing sleeve 3a indicated by the arrow c, but receives a pressure when passing through the contact portion with the developer amount regulating means 4, and is frictionally charged. The layer is regulated, and a charged toner coat layer is formed.

  In the present embodiment, a gap of 300 μm is maintained between the developing sleeve 3a and the photosensitive drum 1 at the closest portion. The developing sleeve 3a is applied with a voltage having a DC bias of −350 V and a rectangular wave AC bias of 2400 Hz and 1600 Vpp. On the photosensitive drum 1, an electrostatic latent image of Vd = −550V and Vl = −100V is formed as in the first embodiment. The magnetic toner that has been negatively frictionally charged on the developing sleeve 3a forms a toner image on the photosensitive drum 1 by reciprocating between the photosensitive drum 1 and the developing sleeve 3a in the proximity of the developing portion by the AC bias. To do. The magnet roller in the developing sleeve 3a is provided with a magnetic pole near the developing portion. In this embodiment, the magnetic force on the surface of the developing sleeve 3a is set to 800 G by this magnetic pole, so that the toner having an improper charge that cannot be controlled by the potential setting described above accidentally jumps to the dark portion Vd portion. To suppress.

(Example and comparative example in Embodiment 2)
Below, the Example and comparative example of the control member in Embodiment 2 are described.

Example 14
The toner regulating member (FIG. 13) in this example basically conforms to Example 2 (FIG. 6), but is different from that applied to the developing device D of Embodiment 2.

Comparative Example 11
The toner regulating means 4 in the comparative example 11 is basically configured in the same manner as the comparative example 4, but differs in that it is applied to the developing device D shown in the second embodiment.

Evaluation Method of Each Example and Comparative Example The evaluation method in the second embodiment is the same as the evaluation method used in the first embodiment, (a) the evaluation of the retention of the toner regulating member without the developer carrier (developing sleeve), ( b) Evaluation of contact stability of the toner regulating member when the developing sleeve is present, and (c) Evaluation of longitudinal density unevenness were performed using the developing sleeve. The results are shown in Table 3.

(Superiority over comparative technique in Embodiment 2)
The toner regulating means 4 of Example 14 of the present invention showed good results in all evaluation results as in the case of the first embodiment.

  That is, it has been found that the effects of the present invention can also be achieved in the second embodiment.

  On the other hand, Comparative Example 11 resulted in an unstable state as in the case of application to Embodiment 1. In particular, (b) the contact stability during rotation of the developing sleeve is more stable than that applied to the first embodiment. About this cause, it thinks as follows.

  In the second embodiment, toner is conveyed magnetically by the developing sleeve 3a. Therefore, the amount of toner conveyed near the intake port of the toner regulating member (flexible sheet member) 40 is significantly larger than that in the first embodiment. That is, in the vicinity of the intake port, the pressure by the toner applied to the flexible sheet member 40 is significantly higher than that in the first embodiment.

  As a result, it is considered that the increase in the pressure by the toner promotes the posture deformation of the flexible sheet member 40 when the developing sleeve rotates, and the contact stability is remarkably lowered.

  However, in Example 14 of the present invention, stable contact stability was obtained even when the developing sleeve was rotated.

  That is, in Example 14 of the present invention, even when the toner amount and pressure conveyed to the vicinity of the toner intake port are increased by magnetic toner conveyance as in the second embodiment, the posture of the flexible sheet member 40 is increased. Deformation can be suppressed. Thereby, the detachment | leave from the supporting member 42 of the flexible sheet | seat member 40 is suppressed, and the stable contact state can be maintained.

  Further, as understood from the above, in this embodiment as well, in the same manner as in the previous embodiment, the desired contact between the toner regulating member and the developer carrier over the longitudinal length with a simple configuration. Since the pressure can be stably obtained, it is possible to suppress the unevenness in the longitudinal density after the endurance, and it is possible to realize a developing device capable of improving the performance in a well-balanced manner without requiring high-precision assembly for downsizing.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. FIG. 2 is a schematic configuration diagram of a process cartridge provided in the image forming apparatus according to the first embodiment. 2 is a schematic configuration diagram of a developing device provided in the image forming apparatus of Embodiment 1. FIG. FIG. 6 is a schematic view for explaining the attachment of the toner regulating means to the developing device and the operation mode thereof. It is the schematic explaining the holding | maintenance property of a flexible sheet member. FIG. 6 is a schematic diagram illustrating contact stability of a flexible sheet member when the developer carrying member rotates. FIG. 6 is a schematic diagram for explaining a contact state between the flexible sheet member and the developer carrier when the angle α = β formed by the flexible sheet member and the developer carrier. It is the schematic explaining suppression of the longitudinal direction nonuniformity generation | occurrence | production in a flexible sheet | seat member. FIG. 3 is a schematic diagram of a developing device according to a first embodiment to which the toner regulating unit of Comparative Example 1 is applied. 6 is a schematic diagram of toner regulating means of Comparative Examples 2 and 3. FIG. 6 is a schematic diagram of toner regulating means of Comparative Examples 4 and 5. FIG. FIG. 3 is a schematic configuration diagram of an image forming apparatus according to a second embodiment. FIG. 4 is a schematic configuration diagram of a developing device provided in an image forming apparatus of Embodiment 2. It is the schematic of the image development apparatus of Embodiment 2 to which the conventional toner control means is applied. It is a figure which shows the holding | maintenance evaluation result of the flexible sheet | seat member before developing agent carrier incorporation. It is a figure which shows the contact stability evaluation result of the flexible sheet | seat member at the time of a developing carrier rotation. It is a figure which shows the longitudinal density non-uniformity evaluation result of a flexible sheet member. Shows the overall evaluation results of the retention property of the flexible sheet member before incorporation of the developer carrier, the contact stability of the flexible sheet member when the developer carrier rotates, and the longitudinal density unevenness evaluation of the flexible sheet member FIG. It is a figure which shows a developer aggregate evaluation result.

Explanation of symbols

1 (1y, 1m, 1c, 1k) Photosensitive drum (image carrier)
2 (2y, 2m, 2c, 2k) Charging roller (charging device)
3 (3y, 3m, 3c, 3k) Development roller (developer carrier)
3a Development sleeve (developer carrier)
4 (4y, 4m, 4c, 4k) Toner regulating means (developer amount regulating means)
5 Supply roller 7 Magnet roller (magnetic field generating means)
40 Flexible sheet member (sheet-like regulating member)
42 flexible sheet support member 43 flexible sheet support part 46 third contact part 47 first contact part 47a first flat part 47b first end face part 48 second contact part 48a second flat part 48b second End surface portion M1 Straight line T1 passing through the first flat surface portion Normal line T2 with respect to the symmetry line between the first flat surface portion and the second flat surface portion. Image forming apparatus 100A Image forming apparatus main body B (By, Bm, Bc, Bk) Process cartridge C (Cy, Cm, Cc, Ck) Cleaning device D (Dy, Dm, Dc, Dk) Developing device

Claims (10)

In order to develop an electrostatic latent image formed on an image carrier, a developer carrier that carries a developer, and a developer amount regulation for regulating the amount of developer carried on the developer carrier A developing device comprising:
The developer amount regulating means has a sheet-like regulating member that contacts the developer carrying member, and a support member that supports the regulating member,
The sheet-shaped regulating member is
A first abutting portion which is one end side in the short direction of the regulating member and is supported by the supporting member on the downstream side in the moving direction of the developer carrier;
A second contact portion supported by the support member on the other end side in the short direction of the regulating member;
A third contact portion that contacts the developer carrier between the first contact portion and the second contact portion in the short direction of the restriction member;
Have
The first contact portion is
Having a first first flat surface portion of the regulating member and a first end surface portion intersecting the flat surface portion;
The first plane portion is
Elastic force generated when the regulating member is bent so that the lateral direction is curved over the longitudinal direction and / or elastic force generated when the third contact portion is pressed against the developer carrier. Is supported in contact with the support member,
The first end surface portion is
Due to the force received from the developer carrier by the third abutment portion being pressed against the developer carrier, the third abutment portion is supported by being in contact with the support member,
The second contact portion is
A planar second flat surface portion of the regulating member;
An angle formed by a perpendicular T1 perpendicular to the symmetry line of the first plane portion and the second plane portion and a straight line M1 passing through the first plane portion is α, and the perpendicular T1 is the moving direction of the developer carrier. Is positive, and the straight line M1 passing through the first plane portion is positive in the direction away from the surface of the developer carrier,
In a state where the surface of the developer carrying member and the regulating member are in contact with each other, an angle formed by a tangent line T2 formed by the developer carrying member and the regulating member coming into contact with a straight line M1 passing through the first plane portion. β and the tangent T2 is positive when the direction of movement of the developer carrier is positive.
The relationship between the angle α and the angle β is
30 ° ≦ β <α <90 ° (1)
The filling,
The third abutting portion abuts on the surface of the developer carrying member with the curvature deformed from the curvature of the bent regulation member in a state in which the developer carrying member does not abut,
A developing device. The relationship between the angle α and the angle β is
30 ° ≦ β <α ≦ 85 ° (2)
β ≦ α-5 ° (3)
The developing device according to claim 1, wherein: The relationship between the angle α and the angle β is
β ≦ 2α-60 ° (4)
The developing device according to claim 1, wherein: The second contact portion has a second end surface portion that intersects the second flat surface portion of the restriction member,
The second flat surface portion has an elastic force generated when the regulating member is bent so as to bend in the short-side direction over the longitudinal direction, and / or the third contact portion is formed with the developer carrier. By the elastic force generated by pressing, it is supported in contact with the support member,
The second end surface portion is supported in contact with the support member by a force received from the developer carrier by the third contact portion being pressed against the developer carrier.
The developing device according to claim 1, wherein:   The developing device according to claim 1, wherein the second contact portion is fixed to the support member. The developer is a magnetic one-component developer,
The developer carrying member includes a magnetic field generating unit that is provided inside the developer carrying member and generates a magnetic field that attracts the magnetic one-component developer to the developer carrying member.
The developing device according to claim 1, wherein   A cartridge having at least the developing device according to any one of claims 1 to 6 and detachable from an image forming apparatus.   8. The apparatus according to claim 7, further comprising at least one of an image carrier that carries an electrostatic image, a charging unit that charges the image carrier, and a cleaning unit that cleans the image carrier. Cartridge.   An image carrier on which an electrostatic image is formed, and a developing device for developing the electrostatic image formed on the image carrier, wherein the developing device is any one of claims 1 to 6. An image forming apparatus comprising the developing device according to item 2.   An image forming apparatus, wherein the cartridge according to claim 7 or 8 is detachable.

Images