JP6134887B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device, a process cartridge, and an image forming device used in an electrophotographic image forming apparatus, and particularly includes a developer carrying member having regularly arranged convex portions and concave portions on a surface thereof. The present invention relates to a developing device, a process cartridge, and an image forming apparatus.

  Here, the image forming apparatus is an apparatus for forming an image on a recording material (recording medium) using an electrophotographic image forming system, and is a copier, a printer, a facsimile apparatus, a word processor, and a complex machine (multifunction printer) thereof. ) Etc. at least. The developing device is a device for visualizing an electrostatic image on an image carrier such as an electrophotographic photosensitive member using a developer. The process cartridge is a cartridge in which an electrophotographic photosensitive member and at least a developing unit serving as a process unit that acts on the electrophotographic photosensitive member are integrally formed into a cartridge that can be attached to and detached from the image forming apparatus main body.

  In an image forming apparatus using an electrophotographic method, generally, an electrostatic image is formed by selectively exposing the outer peripheral surface of a photosensitive drum as a uniformly charged electrophotographic photosensitive member. The toner image is visualized by the toner of the developer carried on the developer carrying member such as a developing roller. Then, the toner image formed on the photosensitive drum is transferred to a recording material, and further, the toner image is fixed on the recording material by applying heat or pressure to the toner image transferred onto the recording material, thereby recording an image. I do.

  In such an image forming apparatus, it is necessary to improve the chargeability of the toner in order to stably form a high-precision image. For example, development having regularly arranged convex portions and concave portions on the surface is required. There has been proposed a developing device that can charge the toner satisfactorily by using the agent carrying roller (see Patent Document 1).

JP 2007-121947 A

  In such a developing device, a developer regulating member is used to regulate the layer thickness of the toner carried on the developer carrying roller, and the toner carried on the surface of the developer carrying roller has the developer regulating member A good charged state can be obtained by being pressed by the flat surface and rolling while in contact with the surface of the developer carrying roller and the developer regulating member.

  However, as a result of intensive studies by the present inventors, when a developer carrying roller having a convex portion and a concave portion provided on the surface is used, a slight difference in the contact condition of the developer regulating member is caused by the developer carrying roller. There is a potential problem in that it greatly affects the layer thickness (hereinafter referred to as “developer regulation amount”) of the toner regulated above.

  As an example, FIG. 1 shows the relationship of the developer regulation amount on the developer carrier with respect to the protrusion amount of the developer regulation member.

  Here, the protruding amount of the developer restricting member (hereinafter referred to as “protruding amount”) is one of the contact conditions of the developer restricting member. This means the moving distance of the tip position of the developer regulating member when the developer carrying member is removed and when the developer carrying member is removed (see FIG. 3, details will be described later).

  Although the developer regulation amount increases as the protruding amount increases, it is affected by the surface shape of the developer carrying member, so that a bending point A and a bending point B are generated.

  In the region where the protruding amount is small (region (a) in FIG. 1), since most of the developer is contained in the recess (see FIG. 2 (a)), good charging characteristics can be obtained. The loading amount of is not a sufficient amount. When the protruding amount is further increased, the filling of the developer into the concave portion is finished, and as a result, the bending point A is generated. After the bending point A (region (b) in FIG. 1), the packing progresses, and a part of the developer overflows on the top surface of the convex portion (see FIG. 2 (b)). After passing the bending point B (region (c) in FIG. 1), the developer that could not enter the concave portion forms one or more developer layers on the top surface of the convex portion (see FIG. 2 (c)). This adversely affects the charging characteristics of the developer.

  That is, it is difficult to secure the amount of developer required for image formation in the region until the bending point A is generated (region (a) in FIG. 1), and the region after the bending point B (region in FIG. 1). In (c)), not only the characteristics of the developer carrying roller as described above are lost, but also various inconveniences occur in image formation and the like.

  Therefore, in order to exhibit the performance of the developer carrying member having convex portions and concave portions on the surface, the developer regulating member protrudes in the region from the bending point A to the bending point B (region (b) in FIG. 1). It was essential to adjust the amount and maintain that state.

  However, in the region from the bending point A to the bending point B, the change rate of the developer regulation amount with respect to the protrusion amount (corresponding to the slope of the straight line in FIG. 1) is very large, so the desired developer regulation amount (set amount). Because the dimensional tolerance (range from the upper limit value to the lower limit value) of the protruding amount (center value) with respect to the allowable fluctuation amount (range from the upper limit value to the lower limit value) becomes extremely narrow, adjustment and assembly are extremely difficult.

  In addition, even with an adjusted development device, the developer regulation amount is likely to fluctuate due to abrasion of the surface of the developer regulation member and the developer carrier, so that it is difficult to control image density and color balance. It is not suitable for a developing device of an image forming apparatus that repeats image formation many times.

  In addition, when the developing device as described above is mounted on a process cartridge with relatively few image forming opportunities, the developing device portion is twisted or distorted due to external power for driving the developing device during image formation. It is difficult to deal with, and image density difference and color unevenness occur within the same page, so that it has not yet been put into practical use.

  The present invention has been made in view of the above circumstances, and by optimizing the configuration of the developing device, the developer carrying state on the developer carrying roller having the convex portion and the concave portion arranged on the surface as described above can be achieved. Provided are a developing device, a process cartridge, and an image forming apparatus, which maintain the charging characteristics of the developer by controlling, further facilitate the attachment and adjustment of the developer regulating member, and have ease of assembly at the mass production level. For the purpose.

  Further, even when image formation is repeated many times, a developing device, a process cartridge, and an image forming device that hardly cause fluctuations in image density and color balance due to abrasion of the developer regulating member and the surface of the developer carrying member The purpose is to provide.

  It is another object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus that hardly change image density and color balance even when subjected to external deformation stress.

In order to achieve the above object, in the present invention,
A developer storage chamber for storing the developer;
A developing chamber disposed adjacent to the developer accommodating chamber;
Partitioning the developer storage chamber and the development chamber, and a partition wall having an opening connecting the developer storage chamber and the development chamber;
A developer carrying member disposed rotatably and carrying and carrying the developer in the developing chamber;
A developer supply member that is disposed in the developing chamber and supplies the developer supplied through the opening to the developer carrier;
In a developing device comprising: a developer regulating member that is disposed so as to abut on the peripheral surface of the developer carrying member and regulates the layer thickness of the developer supplied on the developer carrying member;
The developer supply member is rotatably disposed so as to be in contact with the peripheral surface of the developer carrier, and moves in a direction opposite to the developer carrier in the contact region,
The developer carrying body is provided with a developer carrying surface having a plurality of convex portions configured to carry the developer and a concave portion surrounding each of the plurality of convex portions,
The height difference between the top surface of the convex portion and the bottom surface of the concave portion is 0.8 times or more and less than 5.0 times the weight average particle diameter (D4) of the developer,
On the developer carrying surface, when a virtual entire circumferential surface obtained by extending the top surface of the convex portion in the axial direction and the circumferential direction is defined, the top of the convex portion with respect to the area of the entire circumferential surface is defined. The ratio of the total area of the surface is 3% or more and less than 40%,
A contact position between the developer carrier and the developer regulating member is provided below a contact position between the developer carrier and the developer supply member;
The excess developer regulated by the developer regulating member from the developer carrying member is collected by a developer reservoir disposed below the developing chamber.

  As described above, according to the present invention, the excess developer regulated by the developer regulating member from the surface of the developer carrying member is not directly collected in the developer storage chamber, but the developer storage provided below the development chamber. Collect in the department. Since the excess developer collected in the developer reservoir is already appropriately charged, it is between the partition wall forming the developer reservoir and the contact position between the developer carrier and the developer supply body. It is possible to maintain a moderately compacted state due to electrostatic repulsion between the developers while being easily submerged in the recesses on the surface of the developer carrying member while being gently compressed in the space.

  Further, the contact position between the developer carrier and the developer regulating member is below the contact position between the developer carrier and the developer supply body (the partition wall forming the developer reservoir and the developer). (Between the abutment positions of the carrier and the developer supply body), the developer circulating pressure with respect to each abutment position can be made uniform and gentle, so that the surface of the developer carrier The inventor has estimated that it is possible to further stabilize the dive into the concave portion and to expand the degree of freedom of the contact condition (protrusion amount) between the developer carrier and the developer regulating member. Yes.

  According to the present invention, a developing device, a process cartridge, and an image forming device that are easy to assemble and have excellent mass productivity while allowing good image formation by developing / maintaining good charging characteristics of the developer. A device can be provided. Further, even when image formation is repeated many times, a developing device, a process cartridge, and an image that are less likely to cause fluctuations in image density and color balance due to abrasion of the surface of the developer amount regulating member and the developer carrying member. A forming apparatus can be provided. Furthermore, it is possible to provide a developing device, a process cartridge, and an image forming apparatus that hardly cause fluctuations in image density and color balance even when subjected to external deformation stress.

The relationship between the amount of developer regulation on the developer carrying member with respect to the amount of protrusion of the developer regulating member in a developing device (conventional example) having a developer carrying body having regularly arranged convex portions and concave portions on the surface is shown. FIG. 4 is a partially enlarged photograph showing a regulated state of a developer (toner) carried on the surface of a developer carrying body having regularly arranged convex portions and concave portions on the surface. It is a figure for demonstrating the protrusion amount of a developer control member. 1 is a diagram illustrating a schematic configuration of a one-component developing unit according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a schematic configuration of a developer carrier according to an embodiment of the present invention. It is a figure for demonstrating the top surface of the convex part arrange | positioned on a developing agent carrier. It is a figure for demonstrating the top surface when the shape of the convex part arrange | positioned on a developing agent carrier is different. FIG. 4 is a diagram illustrating a schematic configuration of a one-component developing unit according to Comparative Examples 2 and 3. FIG. 10 is a diagram showing a schematic configuration of a one-component developing unit according to Comparative Example 4. 10 is a diagram showing a schematic configuration of a one-component developing unit according to Comparative Example 5. FIG. In Example 1, it is a figure which shows the relationship of the developer control amount on a developer carrier with respect to the protrusion amount of a developer control member. In Comparative Example 2, it is a diagram showing the relationship of the developer regulation amount on the developer carrier relative to the protruding amount of the developer regulating member.

  Hereinafter, exemplary embodiments suitable for the present invention will be described in detail. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. It is not intended to limit the scope of the invention to the following embodiments. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile apparatus, a word processor, and a multi-function printer (multifunction printer) for forming an image on a recording material (recording medium) using an electrophotographic system. .

  First, an image forming apparatus and an image forming method using the image forming apparatus will be described.

<Regarding Image Forming Apparatus and Image Forming Method>
The image forming method according to the present embodiment includes at least a charging step in which a voltage is applied to the charging member from the outside to charge the electrostatic latent image carrier, and the electrostatic latent image on the charged electrostatic latent image carrier. A latent image forming step for forming the electrostatic image, a developing step for developing the electrostatic image with toner as a developer to form a toner image on the electrostatic latent image carrier, and a toner image on the electrostatic latent image carrier. The image forming apparatus includes a transfer process for transferring to a transfer material and a fixing process for heating and fixing a toner image on the transfer material. In addition to the above-described steps, for example, a cleaning step for removing residuals such as toner remaining on the surface of the electrostatic latent image carrier may be further provided.

  Hereinafter, an image forming apparatus using a one-component developing method will be described as an example of the image forming apparatus according to the present embodiment.

  In an image forming apparatus, a charging unit that is a charging unit that charges the surface of an electrophotographic photosensitive member and a charged electrophotographic photosensitive member are exposed around the electrophotographic photosensitive member, and an electrostatic latent image is exposed according to image information. A latent image forming unit that forms a toner image, a developing unit that is a developing unit that develops an electrostatic latent image with toner to form a toner image, and a toner image formed on the surface of the electrophotographic photosensitive member. A transfer portion which is a transfer means for transferring to the surface of the transfer body and a cleaning portion which is a cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member after transfer are arranged in this order.

  In addition, a fixing unit that is a fixing unit that fixes the toner image transferred to the transfer target is disposed on the transfer unit side of the transfer target in the transfer unit.

  The operation of the image forming apparatus according to this embodiment will be described.

  First, the surface of the electrophotographic photosensitive member is uniformly charged by the charging unit (charging process). Next, light is irradiated onto the surface of the electrophotographic photosensitive member by the exposure unit, and the charged charges in the irradiated portion are removed, and an electrostatic charge image (electrostatic latent image) is formed according to the image information. (Latent image forming step). Thereafter, the electrostatic charge image is developed by the developing unit, and a toner image is formed on the surface of the electrophotographic photosensitive member (developing step).

  For example, consider a digital electrophotographic copying machine that uses an organic photoconductor as an electrophotographic photoconductor and uses a laser beam as an exposure unit. In this case, the surface of the electrophotographic photosensitive member is negatively charged by the charging unit, a digital latent image is formed in a dot shape by the laser beam light, and toner can be applied by the developing unit to the portion irradiated with the laser beam light. Visualized.

  Subsequently, a transfer body such as paper is superimposed on the toner image at the transfer section, and a charge having a polarity opposite to that of the toner is applied to the transfer body from the back side of the transfer body, and the toner image is transferred by electrostatic force. It is transferred to the body (transfer process). The transferred toner image is subjected to heat and pressure by a fixing member in a fixing unit, and is fused and fixed to a transfer target (fixing step).

  On the other hand, the toner remaining on the surface of the electrophotographic photosensitive member without being transferred is removed by a cleaning unit (cleaning step). One cycle is completed in a series of processes from charging to cleaning.

  Note that the toner image may be transferred to a transfer target via a transfer member such as an intermediate transfer member.

  Hereinafter, a charging unit, an electrostatic latent image carrier, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a fixing unit in the image forming apparatus will be described.

[Charging means]
As the charging unit as the charging means, for example, a charger using corona discharge, a conductive or semiconductive charging roll, or the like can be used. A contact-type charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member or may apply an alternating current superimposed thereon. By such a charging unit, the surface of the electrophotographic photosensitive member is charged by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be further provided.

[Electrostatic latent image carrier]
The electrostatic latent image carrier has a function of forming at least a latent image (electrostatic charge image). As the electrostatic latent image carrier, an electrophotographic photosensitive member is preferably exemplified. An electrophotographic photoreceptor has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer, a charge generation layer containing a charge generation material, and a photosensitive layer containing a charge transport layer containing a charge transport material are formed in this order, if necessary. It is. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single layer type photoreceptor included in the above layer may be used, but a laminated type photoreceptor is preferred. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

[Exposure means]
There are no particular limitations on the exposure unit that is the exposure means, and for example, an optical system device that can expose a light source such as a semiconductor laser beam, LED light, or liquid crystal shutter light to the surface of the electrostatic latent image carrier in a desired image-like manner. Etc.

[Development means]
The developing unit, which is a developing unit, includes at least a developer carrying member, a developer (toner), and a developer regulating member. If necessary, a developer supply for supplying the developer to the developer carrying member. It has a member and a stirring conveyance member. The developer carrying member supplies the developer to the electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member. For example, the developer carrying member is a cylinder or cylinder made of a nonmagnetic metal or a polymer material. It is a shaped member. The developer carrying member is rotatably installed so as to face the electrophotographic photosensitive member, and is provided with a developing bias applying unit that applies a developing bias.

  Further, a developer regulating member is provided on the upstream side in the rotation direction of the developer carrier with reference to the position where the developer carrier and the electrophotographic photosensitive member face each other. The developer regulating member is a member that equalizes the layer thickness of the developer carried on the peripheral surface of the developer carrying member, and can be composed of, for example, a metal blade.

  When the developer is a non-magnetic one-component toner, the developer conveyed by the agitating / conveying member or the like is supplied directly and / or to the surface of the developer carrying member by the developer supply member. A predetermined developing bias is applied between the developer carrying member and the electrophotographic photosensitive member, and the developer on the developer carrying member flies onto the electrophotographic photosensitive member in accordance with the electrostatic latent image, and toner It becomes an image (visible image).

[Transfer means]
Examples of the transfer unit that is a transfer unit include a transfer unit that applies a charge having a reverse polarity to the toner from the back side of the transfer target, and transfers the toner image to the transfer target by electrostatic force, or the transfer target. A transfer roll and a transfer roll pressing device using a conductive or semiconductive roll that directly contacts and transfers to the surface of the film via a transfer medium can be used. A direct current may be applied to the transfer roll as a transfer current applied to the electrostatic latent image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll can be arbitrarily set according to the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed, and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of transferring directly to a transfer medium such as paper or a method of transferring to a transfer medium via an intermediate transfer member may be used.

  A known intermediate transfer member can be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

[Cleaning means]
The cleaning unit, which is a cleaning means, may be selected as appropriate as long as it cleans the residual toner on the electrostatic latent image carrier, such as a blade cleaning method, a brush cleaning method, or a roll cleaning method. . Among these, it is preferable to use a cleaning blade having elasticity.

[Fixing means]
The fixing unit, which is a fixing unit (image fixing device), fixes a toner image transferred to a transfer medium by heating, pressing, or heating and pressing, and includes a roller-like or belt-like fixing member. It is.

  The image forming apparatus as described above can form an image on a recording material (for example, recording paper, plastic sheet, etc.) according to the image information, and the image information is an image reading apparatus connected to the image forming apparatus. Alternatively, it is input from a host device such as a personal computer that is communicably connected to the image forming apparatus main body.

  Next, the developing device that is the developing means of the image forming apparatus as described above will be described in more detail.

[Description of developing device]
FIG. 4 is a cross-sectional view showing a schematic configuration of the developing device 100 according to the present embodiment, which is mounted on the image forming apparatus as described above. For example, an image forming apparatus provided with a developing device 100 corresponding to each color of magenta, yellow, cyan, and black forms a color image using each color of magenta, yellow, cyan, and black by development by the developing device 100. In addition to the developing device 100 including a developing roller 110 (developer carrier) that forms a toner image, the image forming apparatus includes a recording medium transport unit that transports a sheet, and a transfer unit that secondarily transfers the toner image onto the sheet. And a photosensitive drum 30 that is an electrostatic latent image carrier on which an image is formed on the peripheral surface, and a fixing unit that adheres the toner image to the paper.

  When an image signal of a recorded image is input to such an image forming apparatus, the control unit of the image forming apparatus uniformly charges the surface of the photosensitive drum 30 to a predetermined potential by a charging roller based on the received image signal. To charge. Thereafter, the exposure unit irradiates the surface of the photosensitive drum 30 with laser light to form an electrostatic latent image. On the other hand, in each developing device 100, the toner T (developer) in the developing chamber is carried on the developing roller 110 by the toner supply roller 120 (developer supply body).

  Then, when the toner is conveyed to a region facing the photosensitive drum 30 by the rotation of the developing roller 110, the toner carried on the developing roller 110 becomes an electrostatic latent image formed on the peripheral surface of the photosensitive drum 30. The electrostatic latent image is developed. Such development is performed for each color of magenta, yellow, cyan, and black. The toner image thus formed is primarily transferred from the photosensitive drum 30 to the transfer belt in a region where the photosensitive drum 30 and the transfer belt face each other. Then, the toner image is secondarily transferred onto the sheet conveyed by the recording medium conveyance unit. Thereafter, the sheet onto which the toner image has been secondarily transferred is conveyed to the fixing unit and fixed, and is discharged outside the image forming apparatus.

  Here, as illustrated in FIG. 4, the developing device 100 includes a developer having a toner supply roller 120, a toner storage chamber 130 (developer storage chamber), and an elastic contact body 142 in addition to the above-described development roller 110. A regulating member, a developing chamber 150, a toner reservoir 160 (developer reservoir), a partition wall 170, a conveying member 135, and a stirring member 165 are provided. In the image forming apparatus, the developing device 100 is provided corresponding to each color of magenta, yellow, cyan, and black, but the basic configuration is the same except that the type of toner as a developer is different. Therefore, the individual description is omitted below.

  The toner storage chamber 130 is a chamber for storing the toner T. The developing chamber 150 is a chamber in which development is performed by the developing roller 110, and is disposed adjacent to and above the toner storage chamber 130. A partition wall 170 is provided between the toner storage chamber 130 and the developing chamber 150, and the partition wall 170 partitions both the chambers 130 and 150. An opening 172 is provided in a part of the partition wall 170, and the toner storage chamber 130 and the developing chamber 150 are connected via the opening 172. The toner storage chamber 130, the developing chamber 150, and the partition wall 170 are integrally formed.

  The toner storage chamber 130 is provided with a conveying member 135 that conveys the toner T to the developing chamber 150. The transport member 135 is a rotatable transport member, and rotates to perform a predetermined amount of toner T stored in the toner storage chamber 130 through the opening 172 of the partition wall 170 into the developing chamber 150. Transport.

  The toner supply roller 120 is a toner T in which the toner T supplied from the toner storage chamber 130 by the conveying member 135 and the toner T scraped off from the developing roller 110 by the regulating member 140 described later are agitated and mixed by the agitating member 165. Is a supply member for supplying the toner to the developing roller 110. The toner supply roller 120 is disposed in the developing chamber 150 so as to face the developing roller 110 so as to abut on the circumferential surface of the developing roller 110. The toner supply roller 120 is made of an elastic member such as polyurethane foam, and is formed so as to be elastically deformable. The toner supply roller 120 is in contact with the developing roller 110 in an elastically deformed state.

  The toner supply roller 120 rotates, for example, counterclockwise, and is configured to move in the opposite direction to the developing roller 110 in a contact area with the developing roller 110 that also rotates counterclockwise. The agitated and mixed toner T is attached to the surface of the toner supply roller 120 having such a configuration, and the surface of the toner supply roller 120 comes into contact with the surface of the developing roller 110 (see FIG. 5), thereby the toner. The toner T is supplied from the supply roller 120 to the developing roller 110, and the developing roller 110 carries the toner. At the same time as the supply of the toner T, the toner supply roller 120 peels off the toner T that has not been used for development through the development nip with the photosensitive drum 30 from the development roller 110, and the toner T is developed for a long time. It also has a function of preventing the charge amount from excessively rising due to staying on 110.

  The developing roller 110 carries the toner T supplied from the toner supply roller 120 on its surface, conveys the toner T to a region facing the photosensitive drum 30, and is formed on the peripheral surface of the photosensitive drum 30. This is a member for moving the toner T to the electrostatic latent image and developing the electrostatic latent image. The member is opposed to the toner supply roller 120 so as to abut on the peripheral surface of the toner supply roller 120 and is also photosensitive drum 30. Is disposed in the developing chamber 150 so as to face the surface.

[Configuration of developer carrier]
The developing roller 110 has a plurality of convex portions 112 configured to carry a developer and a surface having a concave portion 114 surrounding each of the plurality of convex portions 112 (hereinafter referred to as a “developer carrying surface”). For example, after surface processing a roller base material such as aluminum alloy or iron alloy by a known method such as a rolling method or an etching method, it is manufactured by adding an additional process such as polishing or plating as necessary. Is done.

  FIG. 5 is an example of a preferred embodiment of the present invention. The convex portion 112 on the surface of the developer carrying member of the developing roller 110 has a rhombus or square shape, and one diagonal line is the rotation axis ( It is formed to be parallel to the X direction in the figure. In this case, when the convex portion 112 is viewed in cross section along the line CC, it exhibits a trapezoidal shape.

  The developer carrying surface has a height difference between the top surface of the convex portion 112 and the bottom surface of the concave portion 114 that is not less than 0.8 times and less than 5.0 times the weight average particle diameter (D4) of the developer. On the support surface, the top surfaces of the plurality of convex portions 112 forming a part of the cylindrical surface having the same top surface are extended in the axial direction (X direction in FIG. 5A) and the circumferential direction (the same Y direction). The ratio of the total area of the top surfaces of the plurality of protrusions 112 to the area of the entire periphery surface (hereinafter referred to as the “area ratio of the top surface of the protrusions”) Is set to be 3% or more and less than 40%.

  Here, in the present invention, the height difference between the top surface of the convex portion 112 of the developing roller 110 and the bottom surface of the concave portion 114 and the ratio of the total area of the top surface of the convex portion 112 are defined as follows.

  As shown in FIG. 6 (a), the surface shape near the top of any convex part and the bottom of the concave part surrounding the convex part is measured, and the highest point existing near the top of the convex part is present at the bottom of the concave part. The lowest point to be identified is specified, and the height difference between them (hereinafter referred to as “maximum height difference”) is measured.

  The same measurement is performed on other convex portions existing on the developer carrying member, and the average value of each obtained maximum height difference is used to determine the height between the top surface of the convex portion and the bottom surface of the concave portion. It is defined as “difference” (hereinafter referred to as “height difference H between the convex portion and the concave portion”).

  On the other hand, the ratio of the total area of the top surface of the convex portion to the area of the virtual peripheral surface of the developer carrying surface of the developer carrying body is defined as follows.

  As shown in FIG. 6B, first, a lower point corresponding to 10% of the height difference H (hereinafter referred to as “10% lower point”) is determined from the highest point of any convex portion, When the surface of the convex portion extending between the contour lines connecting the lower point of 10% from the highest point of the convex portion is regarded as the top surface of the convex portion, and when the top surface of the convex portion 112 is projected onto the plane from vertically above The area of the projected image that can be produced is measured (see FIG. 6C).

  Further, the same measurement is performed on other convex portions existing on the developer carrying member, and the average value thereof is defined as the “area of the top surface of the convex portion” in the present invention (hereinafter referred to as “the top surface of the top surface”). Area "), the total area of the top surface of the convex portion is determined by multiplying the area of the top surface by the total number of convex portions existing on the developer carrying surface.

  Specifically, when the developer carrying member is a developing roller, eight different convex portions are selected at a total of three locations near the central portion and the left and right end portions of the developing roller, and the maximum height difference is selected. After the measurement, the average value thereof is calculated, and the height difference H between the convex portion and the concave portion defined in the present invention is determined (see FIG. 6B). After that, determine the 10% lower point, determine the area of the top surface of the convex part, finally determine the total area of the top surface of the convex part, and total the top surface of the convex part occupying the entire developer carrying surface Calculate the area percentage.

  Even when the shape of the convex portion is rounded, the height difference H and the ratio of the total area of the top surface can be obtained by the same method as described above (see FIG. 7).

  For the shape measurement of the developer carrying surface on the developer carrying body as described above, a conventionally known method can be used, for example, a non-contact type surface shape measuring device, a shape measuring laser microscope, etc. The obtained surface shape information can be geometrically determined on the drawing by analyzing with the analysis tool attached to the apparatus as described above, or using CAD (Computer aided design) or the like.

FIG. 3 is an example of a preferred embodiment of a developer regulating member for the present invention, and includes a base 143, an elastic contact body 142 and an elastic member 141 that supports and fixes the elastic contact body 142 to the base 143. Blade 140.
The elastic contact body 142 has an end portion extending in parallel with the axial direction of the developing roller 110, and the end portion is in contact with the bottom surface of the concave portion 114 existing on the developer carrying surface provided on the surface of the developing roller 110. It is preferable that the interval (hereinafter referred to as “interval with the bottom surface”) is larger than the weight average particle diameter of the toner T. When the distance from the bottom surface is equal to or less than the weight average diameter of the toner T, not only a sufficient amount of toner can be secured on the developing roller, but also image defects on vertical stripes are likely to occur.

As shown in FIG. 3, a developer regulating member such as an elastic blade is brought into pressure contact with the surface of the developer carrying member, and the “projecting amount” of the developer regulating member is changed so that a desired amount is formed on the surface of the developer carrying member. A thin layer of developer (toner) in an amount can be formed.
In the present invention, the “protruding amount” of the developer regulating member refers to the development existing on the extension line passing through the tip of the developer regulating member from the rotation center of the developer carrying member and reaching the outer periphery of the developer carrying member. This is the distance J from the intersection with the pressure contact surface side of the tip of the agent regulating member to the intersection with the outer peripheral surface of the developer carrier, and can be determined geometrically on the drawing by CAD or the like.

  As a simple measuring method, there is a method of actually measuring the length from the contact mark between the developer regulating member and the developer carrying member to the tip of the developer carrying member, and the like can be used instead.

  Further, the elastic blade 140 regulates the layer thickness of the toner carried on the top surface of the convex portion 112 of the developing roller 110 so that the toner particles become one layer or less. That is, the elastic blade 140 prevents excessive toner particles from being carried on the top surface of the convex portion 112 of the developing roller 110. As a result, the toner particles carried on the developer carrying surface of the developing roller 110 can roll uniformly and efficiently, so that it is possible to quickly shift to a charged state suitable for development. On the contrary, when excessive toner particles are present on the top surface of the convex portion 112, not only the excessive toner particles themselves cannot be given good charging, but also the toner particles are inhibited from rolling. The overall charged state deteriorates.

  The elastic blade 140 is disposed such that the contact position S2 with the developer carrier is lower than the contact position S2 between the developer carrier and the developer supply member (see FIG. 4). . The elastic blade 140 adjusts the layer thickness of the toner T supplied from the toner supply roller 120 to the developing roller 110 before the developing roller 110 moves the toner to the photosensitive drum 30. Due to this adjustment, excess toner T out of the toner T carried by the developing roller 110 is scraped off by the elastic blade 140 and collected in the toner storage unit 160. The toner storage section 160 is provided with a stirring member 165. The surplus toner T and the toner T newly supplied from the toner storage chamber 130 are stirred and mixed by the stirring member 165 and used for the next development. It is done.

  As described above, according to the present invention, the excess developer regulated by the developer regulating member from the surface of the developer carrying member is not directly collected in the developer storage chamber, but the developer storage provided below the development chamber. Collect in the department. Since the excess developer collected in the developer reservoir is already appropriately charged, it is between the partition wall forming the developer reservoir and the contact position between the developer carrier and the developer supply body. It is possible to maintain a moderately compacted state due to electrostatic repulsion between the developers while being easily submerged in the recesses on the surface of the developer carrying member while being gently compressed in the space.

  Further, in the developing device 100, the contact position S1 between the developing roller 110 and the elastic blade 140 is lower than the contact position S2 between the developing roller 110 and the toner supply roller 120 (the partition wall 170 that forms the toner reservoir 165). Between the contact position S1 of the developing roller 110 and the toner supply roller 120), the circulation pressure of the toner particles with respect to each contact position can be made uniform and gentle. The present inventors have estimated that it is possible to further stabilize the dive into the recess and to expand the degree of freedom of the contact condition (protrusion amount) between the developing roller 110 and the developer regulating member 140. Yes.

  Further, in the developing device 100, since the dimensional tolerance of the protruding amount J of the elastic blade 140 with respect to the developing roller 110 is wide, abrasion of the contact portion of the elastic blade 140 due to numerous image formations occurs and the protruding amount is large. Even if it changes, it becomes easier for the amount of protrusion after wear to remain within a predetermined dimensional tolerance. Furthermore, since the self-cleaning can be performed by setting the contact portion of the elastic blade 140 to be worn out, for example, the surface hardness ratio of the elastic contact member 142 to the developing roller 110 is 0. A plate-like member formed of phosphor bronze or stainless steel of 20 or more and less than 1.00 is preferably selected.

  Thus, filming of the toner can be prevented, so that not only the charged state of the toner particles but also the supported state of the toner particles can be maintained in the best state. As a result, for example, the occurrence of vertical stripe-shaped image density unevenness is suppressed, and deterioration / fluctuation of image density, toner contamination in a non-image area corresponding to the print background, fine line reproducibility, color tone, etc. are minimized. Therefore, it is possible to provide an excellent developing device capable of achieving the above.

  Note that when the developing device is used in a process cartridge type image forming apparatus that is easily affected by external deformation stress, the effect is very significant.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

<Manufacturing example of developer>
[Production example of one-component developer (black color)]
The following components were dry mixed and then kneaded with a biaxial kneader.
Styrene-butyl acrylate resin (Mw = 50,000, Tg = 60 ° C.) 100 parts by mass Carbon black (average particle size = 40 nm) 5 parts by mass Aluminum compound of salicylic acid derivative (manufactured by Orient Chemical Co., Ltd.) 1 part by mass Ester wax (peak temperature of DSC maximum endothermic peak = 70 ° C.) 5 parts by mass

  The obtained kneaded product was cooled and coarsely pulverized to approximately 1 mm or less, and then finely pulverized using a mechanical pulverizer, and the obtained finely pulverized product was classified to obtain classified particles.

Next, 100 parts by mass of the classified particles obtained above were put into a dry mixing apparatus together with the following components, premixed at a low rotational speed, and then further dry mixed at a high rotational speed for 5 minutes. .
-Hydrophobized silica fine particles (number average particle size = 0.1 µm) 0.5 parts by mass-Hydrophobized silica fine particles (number average particle size = 0.02 µm) 1.0 parts by mass-Hydrophobized titania fine particles (number) (Average particle diameter = 0.02 μm) 1.0 part by mass

  After dry mixing, coarse particles were removed by sieving to obtain a black one-component developer.

[Production example of one-component developer (yellow color)]
One-component development of yellow color in the same manner as in the above “Example of production of one-component developer (black color)” except that 7 parts by mass of “CI Pigment Yellow 180” is used instead of carbon black. An agent was obtained.

[Production example of one-component developer (magenta color)]
Magenta one-component development in the same manner as in the above “Manufacturing example of one-component developer (black color)” except that 7 parts by mass of “CI Pigment Red 180” is used instead of carbon black. An agent was obtained.

[Production example of one-component developer (cyan)]
One component of cyan color in the same manner as in the above “Example of production of one-component developer (black color)” except that 5 parts by mass of “CI Pigment Blue 15: 3” is used instead of carbon black. A system developer was obtained.

  In the present invention, the weight average particle diameter (D4) of the one-component developer and the number of toner particles of 3 μm or less in the number-based particle size frequency distribution are, for example, a precision particle size distribution measuring device “Multisizer 3” (Beckman Coulter). According to the operation manual of the measuring apparatus, “Toner particle size distribution measuring method (http://www.beckmancoulter.co.jp/product/ product03 / toner / 04.html) etc. can be used as a reference.

  As a specific measurement method, 100 ml of an electrolytic solution “ISOTONE II PC” (manufactured by Beckman Coulter, Inc.) is prepared in a beaker for preparing a suspension, and a surfactant as a dispersant (preferably LAS; linear) After adding 0.1 g of sodium alkylbenzene sulfonate), 5 mg of a measurement sample (toner particles or one-component developer) is added to obtain a toner suspension. Next, in order to improve the dispersibility of the measurement sample in the toner suspension, an ultrasonic wave irradiation process from the outside is performed for 2 minutes using an ultrasonic bath or the like to prepare a measurement sample. An aperture tube having an opening diameter of 50 μm is used, and the volume and number of the measurement sample are measured for each channel to calculate the volume distribution and number distribution of the measurement sample. The weight average particle diameter (D4) of the measurement sample is obtained from the calculated distribution.

  Each of the one-component developers of the respective colors obtained in the above production examples has a weight average particle diameter (D4) of 6.5 μm, and the number of developer particles of 3 μm or less in the number-based particle size frequency distribution is 10. It manufactured so that it might become number%.

<Example of developing developer carrier>
[Production Example 1 of Developer Carrier]
After polishing the outer peripheral surface (hereinafter referred to as “cylindrical surface”) of a cylindrical roller base material made of a carbon steel pipe having a diameter of 16 mm with a centerless polishing machine, two grooves (see FIG. 5) intersecting the cylindrical surface. (B) (grooves in the directions indicated by arrows A and B), a roller base is provided in the rolling device including the first and second dies on which ridges corresponding to the respective grooves are formed. The material was installed. Then, while rotating each die and the roller base material at a constant speed, the die was pressed while feeding the roller base material, and the first and second grooves were rolled into the roller base material.

  As a result, the cylindrical surface has a plurality of regularly arranged convex portions and concave portions surrounding the convex portions on the surface, and the surfaces of the convex portions are part of the same cylindrical surface. Got a building roller.

  The cylindrical surface of the obtained rolling roller was again polished with a centerless grinder to adjust the height difference between the convex portion and the concave portion, and then degreased by being immersed in a heated degreasing solution.

  Further, the degreased rolling roller is immersed in a heated Ni-P plating bath, electrolessly plated on the cylindrical surface, then washed and dried to obtain the surface structure shown in FIG. A developing roller “developer carrier T-1” having a developer carrying surface (see FIG. 5A) was produced.

  The height difference between the convex portion and the concave portion formed on the cylindrical surface of the obtained “developer carrier T-1” is 12 μm, the area ratio of the top surface of the convex portion is 11%, and the Vickers hardness of the surface of the developing roller is 700 Hv.

[Production Examples 2 to 5 of developer carrier]
Except for changing the manufacturing condition of the rolling roller and the adjustment condition of the height difference between the convex part and the concave part by polishing, and changing the content of the P component and the heat treatment condition during electroless plating, the “developer carrier” In the same manner as in Production Example 1 ”, developing rollers“ developer carrying bodies T-2 to 5 ”in which the height difference between the convex portion and the concave portion, the area ratio of the top surface of the convex portion, and the surface hardness are different were produced.

[Production Examples 6 and 7 of developer carrier]
Except for processing the cylindrical surface by etching and changing the content of P component and the heat treatment conditions during electroless plating, in the same manner as in “Manufacturing Example 1 of the developer carrying member”, the convex portions and the concave portions are formed. Developing rollers “developer carrying bodies E-1 and E-2” having different height difference, area ratio of the top surface of the convex portion and surface hardness were manufactured.

[Production Examples 1 to 3 for Comparative Developer Carrier]
Except for changing the manufacturing condition of the rolling roller and the adjustment condition of the height difference between the convex part and the concave part by polishing, and changing the content of the P component and the heat treatment condition during electroless plating, the “developer carrier” In the same manner as in “Production Example 1”, comparative developing rollers “developer carrying bodies t-6 to 8” having different height differences between the convex portions and the concave portions, the area ratio of the top surface of the convex portions and the surface hardness were produced.

[Production Example 4 for Comparative Developer Carrier]
Except for processing the cylindrical surface by etching and changing the content of P component and the heat treatment conditions during electroless plating, in the same manner as in “Manufacturing Example 1 of the developer carrying member”, the convex portions and the concave portions are formed. A comparative developing roller “developer carrier e-3” having different height difference, area ratio of the top surface of the convex portion and surface hardness was manufactured.

  The contents of the developing roller and the comparative developing roller obtained in Production Examples 1 to 7 of the developer carrier and Comparative Examples 1 to 4 of the developer carrier for comparison are summarized in Table 1 below.

<Example 1>
As the image forming apparatus, the developing unit of “SAMSUNG MultiXpress CLX-9301NA (manufactured by Samsung Electronics Co., Ltd.)”, which is a color multifunction device compatible with A3 size paper, is replaced with “one-component developing unit-A1” shown in FIG. Then, a modified / adjusted image was formed so that image formation was possible.

  As the developer carrying member of the black developing unit of the image forming apparatus, the “developer carrying member T-1” obtained in “Development carrying member production example 1” is used. A stainless steel thin plate (plate thickness = 80 μm, Vickers hardness = 350 Hv) was used as the elastic contact body. Further, 150 g of the black one-component developer obtained in the above-mentioned “Production Example of One-Component Developer (Black Color)” was added.

  Accordingly, the height difference H between the convex portion and the concave portion of the “developer carrier T-1” at this time is 1.9 times the weight average particle diameter of the black one-component developer, and the developer The ratio of the surface hardness of the contact portion of the developer regulating member to the surface hardness of the carrier was 0.50.

[Evaluation of developer regulating amount on the surface of the developing carrier relative to the protruding amount of the developer regulating member]
In order to evaluate the developer regulation amount (hereinafter referred to as “regulation amount”) on the surface of the developer carrier relative to the protrusion amount (hereinafter referred to as “protrusion amount”) of the developer regulating member, At 23 ° C./50% Rh), the regulation amount with respect to an arbitrary protruding amount was measured.

  First, a developer amount regulating member whose protruding amount is adjusted by a dedicated jig is attached to the developing unit, and after printing a solid image, the developing unit is operated for 15 seconds with no developer consumed, and a developer carrying member After stabilizing the developer regulation state on the surface, the regulation amount was measured. Note that a suction charge amount measuring device was used for measurement of the regulation amount.

  FIG. 11 shows the measurement result of the developer regulation amount on the surface of the development carrier relative to the protrusion amount of the developer regulation member at this time.

The developer restriction amount on the developer carrying member with respect to the protrusion amount of the developer restriction member causes the bending point A after the restriction amount increases uniformly with the increase of the protrusion amount. When the protruding amount was further increased, the bending point B was generated again when the protruding amount was 0.83 mm. At this time, the developer regulation amount on the surface of the developer carrying member was 0.34 mg / cm ² , and when the top surface of the convex portion on the surface of the developer carrying member was observed, the developer particles were regulated to one layer or less. Furthermore, when the protruding amount was increased, the developer particles on the surface of the developer carrying member filled up all the convex portions, and the developer particles changed to a state where they were carried more than one layer.

When the developer regulating amount on the surface of the developer carrying member is 0.30 mg / cm ² , the protruding amount of the developer amount regulating member is 0.53 mm, and the allowable variation amount of the developer regulating amount is ± 0.02 mg / cm ^2. The dimensional tolerance of the protruding amount when it was set to cm ² was assured as 0.32 mm (upper limit: 0.69 mm, lower limit: 0.37 mm), and the assemblability that can be handled very easily even during mass production was shown.

[Image quality evaluation]
In a normal temperature and humidity environment (23 ° C./55% Rh), after adjusting the developer regulation amount on the surface of the developer carrying member to 0.30 mg / cm ² , the black color is changed by the single color mode while supplying the developer. 30,000 images were printed out, and the image quality of the images obtained immediately after starting printing and at the end of printing was evaluated. As a transfer material, Fuji Xerox Co., Ltd. full color copier paper C2 (70 g / cm ² , A4 size) was used.

  As a result, the obtained image maintains excellent image density and small-point character image reproducibility from the start to the end of printing, and also suppresses toner contamination in the non-image area. There was no occurrence of vertical stripe-shaped image density unevenness caused by uneven regulation of the developer on the surface.

After the end of evaluation, it was confirmed several points of the developer regulating the amount of the developer carrying member surface was retained within the ^{0.30mg / cm 2 ± 0.02mg / cm} 2. Further, no filming or fixing of the developer was observed on the surface of the developer carrying member, and a good state was maintained.

<Comparative example 1>
The developer regulation amount on the surface of the developer carrying member was adjusted to 0.43 mg / cm ² (a state where developer particles on the surface of the developer carrying member filled all the convex portions and the developer particles were carried more than one layer). Except for the above, an evaluation test was performed in the same manner as in “Example 1”.

  As a result, since the developer regulation amount is excessive, the charged state of the developer becomes insufficient, and the obtained image shows a sufficient image density just after the start of printing, but the small point character image has a line width. The fatness became unclear and toner stains in the non-image area occurred. When the printout is continued in this state, the image density is lowered at the end of 30,000 sheets, and the toner stain in the non-image area is further deteriorated. In addition, vertical stripe-shaped image density unevenness due to developer regulation unevenness on the surface of the developer carrier has also occurred, and when the developer regulation amount on the surface of the developer carrier is confirmed, the axial direction of the developer carrier There was a large variation in the amount of regulation in Japan.

<Comparative example 2>
Instead of “one-component development unit-A1”, the “one-component development unit-A2” shown in FIG. 8A is set so that the rotation direction of the developer supply body is at the contact position with the developer carrier. An evaluation test was performed in the same manner as in “Example 1” except that “having a structure that rotates so as to move in the same direction” was used.

  As a result, since the rotation direction of the developer supply body is changed to move in the same direction as the developer carrier at the contact position, the developer regulation amount on the surface of the developer carrier relative to the projection amount of the regulation member As the amount increased, the regulation amount increased rapidly, and a bending point B was generated when the protrusion amount reached 0.55 mm (see FIG. 12).

When the developer regulation amount on the surface of the developer carrying member is 0.30 mg / cm ² , the protrusion amount of the developer regulation member is 0.45 mm, and the allowable variation amount of the developer regulation amount is ± 0.02 mg / cm 2. It was found that the dimensional tolerance of the protruding amount when it was set to ² could only ensure 0.08 mm (upper limit: 0.49 mm, lower limit: 0.41 mm), causing problems in assembling at the time of mass production.

  Next, image quality evaluation was performed in the same manner as in Example 1. As the rotation direction of the developer supply body is the same as that of the developer carrier, the efficiency of replacing the old and new developers on the surface of the developer carrier is high. In addition to the reduction, the developer particles are packed in the recesses on the surface of the developer carrying member, and the frictional charging associated with the rolling of the developer particles is inhibited. Dirt has occurred. In addition, a plurality of vertical stripe-shaped image shading unevenness caused by uneven developer regulation on the surface of the developer carrying member occurred, and these phenomena worsened as the printout progressed.

  Further, when the developer regulation amount on the surface of the developer carrying member was confirmed after the evaluation was completed, the regulation amount in the axial direction of the developer carrying member was greatly varied.

<Comparative Example 3>
Instead of “one-component development unit-A1”, “one-component development unit-A3” shown in FIG. 8B; a part of the partition wall that divides the developer storage chamber and the development chamber is removed, and development is performed. An evaluation test was carried out in the same manner as in “Example 1” except that the “excess developer regulated by the agent regulating member was directly collected in the developer storage chamber” was used.

  As a result, a part of the partition wall that divides the developer storage chamber and the development chamber is removed, and the developer is changed to a structure that allows the excess developer regulated by the developer regulating member to be directly collected in the developer accommodation chamber. The developer regulation amount on the surface of the developer carrying member with respect to the projecting amount of the regulating member increased rapidly as the projecting amount increased, and a bending point B was generated when the projecting amount was 1.10 mm.

When the developer regulation amount on the surface of the developer carrier is 0.30 mg / cm ² , the protrusion amount of the developer regulation member is 0.81 mm, and the allowable variation amount of the developer regulation amount is ± 0.02 mg / cm 2. It was found that the dimensional tolerance of the protruding amount when it was set to ² could only secure 0.05 mm, causing a problem in assembling at the time of mass production.

  Next, image quality evaluation was performed in the same manner as in Example 1. As a result, a part of the partition wall that partitions the developer storage chamber and the development chamber was removed, and the excess developer regulated by the regulating member was directly contained in the developer. Due to the structure of collecting in the chamber, the amount of developer supplied to the surface of the developer carrying member becomes unstable, the image density is low immediately after the start of printing, and there is a problem in the reproducibility of small point character images. In addition, a plurality of vertical stripe-shaped image shading unevenness caused by uneven developer regulation on the surface of the developer carrying member occurred, and these phenomena worsened as the printout progressed.

  Further, when the developer regulation amount on the surface of the developer carrying member was confirmed after the evaluation was completed, the regulation amount in the axial direction of the developer carrying member was greatly varied.

<Comparative example 4>
As the image forming apparatus, a developer carrier of a toner cartridge of “Color Laser Jet 5550 (manufactured by Hewlett Packard)”, which is a color printer compatible with A3 size paper, was obtained in “Development carrier production example 1”. “Developer carrier T-1” and the elastic contact member of the developer regulating member are replaced with a thin plate of stainless steel (plate thickness = 80 μm, Vickers hardness = 350 Hv). Remodeled / adjusted so that the gap between the image carrier and the image carrier is 200 μm (“one-component developer unit B shown in FIG. 9; the contact position between the developer carrier and the developer regulating member is the developer carrier And a developer supply body above and a position where the excess developer regulated by the developer regulating member is directly collected in the developing chamber ”), the“ one-component system ” Developer Except that charged with one-component developer 280g black color obtained in Production Examples "in black color) was carried out in the same manner as in Evaluation Test as" Example 1 ".

  As a result, the contact position between the developer carrying member and the developer regulating member is provided above the contact position between the developer carrying member and the developer supplying member, and the excess developer regulated by the regulating member is removed. Since the developer is directly collected in the developing chamber, the developer restriction amount on the surface of the developer carrying member with respect to the protrusion amount of the developer restricting member increases rapidly as the protrusion amount increases, and the protrusion amount is 0.90 mm. Occasionally inflection point B occurred.

When the developer regulation amount on the surface of the developer carrying member is 0.30 mg / cm ² , the protruding amount of the regulation member is 0.61 mm, and the allowable variation amount of the developer regulation amount is ± 0.02 mg / cm ² . As a result, it was found that the dimensional tolerance of the protruding amount was only 0.04 mm, which caused problems in assembling in mass production.

  Next, image quality evaluation was performed in the same manner as in Example 1. As a result, the contact position between the developer carrier and the developer regulating member was provided above the contact position between the developer carrier and the developer supply body. The surplus developer regulated by the regulating member is directly collected in the developing chamber, so that the obtained image shows a sufficient image density just after the start of printing, but the non-image area is contaminated with toner. It has occurred. If printing is continued in this state, the toner stain in the non-image area temporarily improved, but the toner stain in the non-image area deteriorated again when the developer was replenished. At the end, the image density also decreased. In addition, vertical stripe-like image density unevenness caused by uneven developer regulation on the surface of the developer carrying member also occurred.

<Comparative Example 5>
As the developing unit, “one-component developing unit-C: FIG. 10 illustrates that the developer supplying member is rotated so that the rotation direction of the developer supplying member moves in the same direction as the developer carrying member, and is regulated by the developer regulating member. An evaluation test was carried out in the same manner as in “Comparative Example 4” except that the “developer having a structure for recovering excess developer in the developer reservoir in the upper part of the developing chamber” was used.

  As a result, the rotation direction of the developer supply body is rotated so as to move in the same direction as that of the developer carrying body, and the excess developer regulated by the developer regulating member is removed from the developer reservoir in the upper part of the developing chamber. Therefore, the developer regulation amount on the surface of the developer carrier relative to the projection amount of the developer regulating member increases rapidly as the projection amount increases, and the inflection point when the projection amount is 0.88 mm. B was produced.

When the developer regulation amount on the surface of the developer carrying member is 0.30 mg / cm ² , the protrusion amount of the regulation member is 0.85 mm, and the allowable variation amount of the developer regulation amount is ± 0.02 mg / cm ² . As a result, it was found that the dimensional tolerance of the protruding amount was only 0.04 mm, which caused problems in assembling in mass production.

  Next, image quality evaluation was performed in the same manner as in “Example 1”. As a result, the rotation direction of the developer supply body was the same as that of the developer carrier, and the excess developer regulated by the regulating member was removed from the developing chamber. Since the toner was collected in the upper developer storage portion, toner stains occurred in the non-image area immediately after the start of printing. Further, as the printout progressed, the image density and small-point character image reproducibility were remarkably lowered, and a plurality of vertical stripe-like image shading unevenness caused by the developer regulating unevenness on the surface of the developer carrying member occurred.

  Further, when the developer regulation amount on the surface of the developer carrying member was confirmed after the evaluation was completed, the regulation amount in the axial direction of the developer carrying member was greatly varied.

  Table 2 shows the configuration of the developing units used in “Example 1 and Comparative Examples 1 to 5”, and Table 3 shows the evaluation results. In addition, the evaluation criteria of each item described in the table are as follows.

[1. Assembly of developer amount regulating member]
In the developer carrying member surface of the developer regulating weight 0.30 mg / cm ^2, the dimensional tolerance of the protrusion amount of the developer regulating member in a case where the allowable variation amount of the developer regulating amount of ± 0.02 mg / cm ² And evaluated according to the following criteria.
A: Dimensional tolerance is 0.3 mm or more (very easy)
B: Dimensional tolerance is 0.2 mm or more and less than 0.3 mm (easy)
C: Dimensional tolerance is 0.1 mm or more and less than 0.2 mm (acceptable level in the present invention)
D: Dimensional tolerance is less than 0.1 mm (It is very difficult and is not possible in the present invention)

[2. Image density]
Print an image with a 5mm square solid patch near the four corners and the center, measure the reflection density of the solid patch with a spectrophotometer Spectroeye (Gretag Macbeth), and calculate the average of the measured values. Calculated and evaluated according to the following criteria.
A: 1.30 or more (very good)
B: 1.15 or more and less than 1.30 (good)
C: 1.00 or more and less than 1.15 (Acceptable level in the present invention)
D: Less than 1.00 (impossible level in the present invention)

[3. Reproducibility of small point character images]
A five-point character image was printed near and at the four corners, and the reproducibility of the obtained character image was evaluated according to the following criteria.
A: Fluctuation amount of thin line width is less than 10% (very good)
B: The fluctuation amount of the line width of the thin line is 10% or more and less than 15% (good)
C: The change of the fine line is 15% or more, and can be confirmed visually (in the present invention, it is an acceptable level).
D: Contact between thin wires and tearing of the thin wires themselves can be easily confirmed visually (in the present invention, it is an unacceptable level)

[4. Non-image area (print background) toner stains]
When forming a white image, the developer present on the photosensitive drum is transferred to the adhesive surface of a mending tape (manufactured by Sumitomo 3M Co.) during the transition from the development process to the transfer process, and the reflection of what is pasted on the paper. Concentration was measured with a spectrophotometer Spectroeye (manufactured by Gretag Macbeth Co., Ltd.), and the numerical value obtained by subtracting the reflection density (blank) when the mending tape was directly applied to the paper from the obtained reflection density was determined. evaluated. A smaller numerical value indicates that toner contamination in the non-image area is suppressed.
A: Less than 0.03 (very good)
B: 0.03 or more and less than 0.07 (good)
C: 0.07 or more and less than 1.00 (Acceptable level in the present invention)
D: 1.00 or more (this is an unacceptable level in the present invention)

[5. Vertical stripe image density unevenness]
A halftone image composed of a halftone dot pattern was printed, the number of occurrences of vertical stripe-like image shading unevenness generated on the obtained halftone image was measured, and evaluated according to the following criteria.
A: Not generated (very good)
B: Slight vertical stripe-like image shading unevenness occurs in one place (good)
C: 2-4 occurrences (acceptable level in the present invention)
D: 5 or more occurrences (in the present invention, it is an impossible level)

<Example 2>
An evaluation test was conducted in the same manner as in “Example 1” except that “Developer support T-2” obtained in “Developer support production example 2” was used as the developer support. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier T-2” is 3.1 times the weight average particle size of the black one-component developer), and the developer carrier The surface hardness ratio of the contact portion of the developer regulating member with respect to the surface hardness was 0.54.

  As a result of the evaluation test, there was no problem in the assemblability of the regulating member and the obtained printout image, and the surface of the developer carrying member was maintained in a good state.

<Example 3>
An evaluation test was conducted in the same manner as in "Example 1" except that "Developer support T-3" obtained in "Developer support production example 3" was used as the developer support. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier T-3” is 0.8 times the weight average particle diameter of the black one-component developer. The surface hardness ratio of the contact portion of the developer regulating member with respect to the surface hardness was 0.39.

  As a result of the evaluation test, there was no problem in the assemblability of the regulating member and the obtained printout image, and the surface of the developer carrying member was maintained in a good state.

<Example 4>
“Developer carrier T-4” obtained in “Developer carrier production example 4” is used as the developer carrier, and a phosphor bronze thin plate is used as the elastic contact member of the developer regulating member. An evaluation test was performed in the same manner as in “Example 1” except that (plate thickness = 100 μm, Vickers hardness = 190 Hv) was used. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier T-4” is 0.9 times the weight average particle diameter of the black one-component developer, The surface hardness ratio of the contact portion of the developer regulating member with respect to the surface hardness was 0.38.

  As a result of the evaluation test, there was no problem in the assembling property of the regulating member and the obtained printout image, and the surface of the developing roller was maintained in a good state.

<Example 5>
An evaluation test was conducted in the same manner as in “Example 1” except that “Developer support T-5” obtained in “Developer support production example 5” was used as the developer support. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier T-5” is 4.8 times the weight average particle diameter of the black one-component developer, The surface hardness ratio of the contact portion of the regulating member with respect to the surface hardness was 0.37.

  As a result of the evaluation test, there was no problem in the assembling property of the regulating member and the obtained printout image, and the surface of the developer carrying member was maintained in a good state.

<Example 6>
“Developer carrier E-1” obtained in “Developer carrier production example 6” is used as the developer carrier, and a stainless steel thin plate (plate) is used as the elastic contact member of the developer regulating member. The evaluation test was performed in the same manner as in “Example 1” except that the thickness = 70 μm and the Vickers hardness = 450 Hv) were used. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier E-1” is 4.9 times the weight average particle size of the black one-component developer, and the surface of the developer carrier The surface hardness ratio of the contact portion of the regulating member with respect to the hardness was 0.90.

  As a result of the evaluation test, the convex portion on the surface of the developer carrying member was deformed by abrasion, and slight fixing of the developer particles was observed, but there was no problem in the assembling property of the regulating member and the obtained printout image. .

<Example 7>
The “developer carrying body E-2” obtained in “Developer carrying body production example 7” is used as the developer carrying body, and a phosphor bronze thin plate (plate thickness = plate thickness = An evaluation test was performed in the same manner as in “Example 1” except that 120 μm and Vickers hardness = 150 Hv) were used. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier E-2” is 4.0 times the weight average particle diameter of the black one-component developer, The surface hardness ratio of the contact portion of the developer regulating member with respect to the surface hardness was 0.20.

  As a result of the evaluation test, although slight filming due to the developer particles occurred on the surface of the developing roller, there was no problem in the assembling property of the regulating member and the obtained printed image.

<Comparative Example 5>
“Developer carrier t-6” obtained in “Production example 1 of developer carrier for comparison” is used as the developer carrier, and a stainless steel thin plate (plate) is used as the elastic contact member of the regulating member. The evaluation test was performed in the same manner as in “Example 1” except that the thickness = 70 μm and the Vickers hardness = 440 Hv) were used. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier t-6” is 3.2 times the weight average particle diameter of the black one-component developer, and the surface hardness of the developing roller. The surface hardness ratio of the contact portion of the restricting member with respect to was 1.02.

  When the developer regulation amount on the surface of the developer carrier was confirmed before the evaluation test, the assembly ratio of the regulation member was satisfied, but the area ratio of the top surface of the convex portion of the developer carrier was 40% or more (43% ), The amount of regulation in the axial direction of the developer carrying member varied greatly.

  In the printout image obtained in the evaluation test, sufficient image quality could not be obtained, for example, image density unevenness due to restriction unevenness and smudges on the printed background occurred from the start of printing. Further, since the surface hardness ratio of the contact portion of the regulating member with respect to the surface hardness of the developer carrying member was 1.00 or more, the wear deformation of the convex portion on the surface of the developer carrying member was remarkable, and the developer particles were fixed. Occurred and had a direct adverse effect on the printed image.

<Comparative Example 6>
An evaluation test was conducted in the same manner as in "Example 1" except that "Developer support t-7" obtained in "Comparative developer support production example 2" was used as the developer support. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier t-7” is 0.6 times the weight average particle size of the black one-component developer. The surface hardness ratio of the contact portion of the regulating member with respect to the surface hardness was 0.50.

  As a result of the evaluation test, the difference in height between the convex portion and the concave portion of the developing roller was less than 0.8 times the weight average particle diameter of the developer. In the printout image, sufficient image quality could not be obtained such as toner smearing in a non-image area from the start of printing.

<Comparative Example 7>
The “developer carrier t-8” obtained in “Comparative developer carrier production example 3” is used as the developer carrier, and a phosphor bronze thin plate (plate) is used as the elastic contact member of the regulating member. The evaluation test was performed in the same manner as in “Example 1” except that the thickness = 120 μm and the Vickers hardness = 150 Hv) were used. At this time, the difference in height between the convex portion and the concave portion of the “developer carrier t-8” is 2.8 times the weight average particle size of the black one-component developer, and the surface hardness of the developing roller. The surface hardness ratio of the contact portion of the regulating member with respect to was 0.15.

  The printout image obtained in the evaluation test was good at the start of printing, but the image quality deteriorated as the printout progressed. Further, since the surface hardness ratio of the contact portion of the regulating member with respect to the surface hardness of the developing roller was less than 0.20, filming due to the developer particles occurred on the surface of the developing roller, and the printout image It had a direct adverse effect.

<Comparative Example 8>
An evaluation test was conducted in the same manner as in "Example 1" except that "Developer support e-3" obtained in "Comparative developer support production example 4" was used as the developer support. At this time, the difference in height between the convex portion and the concave portion of “Developer carrier e-3” was 5.4 times the weight average particle size of the black one-component developer.

  When the developer regulation amount on the surface of the developing roller was checked before the evaluation test, the developer regulating member assembly was satisfactory, but the difference in height between the convex portion and the concave portion of the developer carrying member was the volume of the developer. Since the average particle size was 5.0 times or more, the amount of regulation in the axial direction of the developer bearing member varied greatly.

  Although the printout image obtained in the evaluation test has good image density immediately after the start of printing and the reproducibility of the small-point character image, unevenness in image density due to regulation unevenness and toner smearing in non-image areas occur. Etc., sufficient image quality could not be obtained.

  The evaluation results of the “Examples 2 to 7 and Comparative Examples 5 to 8” are summarized in Table 4 below.

<Example 9>
The developing unit other than the black color of the image forming apparatus used in the above-mentioned “Example 1” is also replaced with “One-component developing unit-A1” shown in FIG. 4 and adjusted / adjusted so that image formation is possible. Each color development unit is modified with the black, yellow, magenta, and cyan monocomponent developers obtained in the above “Developer Production Examples”, and 150 g for each corresponding development unit. I put it in. Further, the “developer carrying body T-1” obtained in “Developer carrying body production example 1” is used as the developer carrying body of “one-component development unit-A1”, and the developer regulating member A stainless steel thin plate (plate thickness = 80 μm, Vickers hardness = 350 Hv) was used as the elastic contact body.

  Accordingly, the height difference between the convex portion and the concave portion of “Developer carrier T-1” at this time is 1.9 times the weight average particle diameter of the one-component developer of each color, and the developer carrier The surface hardness ratio of the contact portion of the developer regulating member with respect to the surface hardness was 0.50.

In the same manner as in “Example 1”, after adjusting the developer regulation amount on the surface of the developer carrier for each color, printing 10,000 color images in full color mode while replenishing the developer. The image quality of the printout images obtained immediately after the start and at the end was evaluated. As a transfer material, Fuji Xerox Co., Ltd. full color copier paper C2 (70 g / cm ² , A4 size) was used.

  As a result of the evaluation test, there is no problem in the assembly of the regulating member and the obtained printout image, while maintaining excellent image density and reproducibility of small-point character images from the start to the end of printing, and non-image areas Thus, a good full-color image without vertical stripe-like image density unevenness caused by uneven developer regulation on the surface of the developer carrying member could be obtained.

  DESCRIPTION OF SYMBOLS 100 ... Development apparatus 110 ... Developer carrier (development roller), 112 ... Convex part, 114 ... Concavity, 120 ... Developer supply body (toner supply roller), 130 ... Developer storage chamber (toner storage chamber), 140 ... Developer regulating member (elastic blade), 150... Developing chamber, 160.

Claims (7)

A developer storage chamber for storing the developer;
A developing chamber disposed adjacent to the developer accommodating chamber;
Partitioning the developer storage chamber and the development chamber, and a partition wall having an opening connecting the developer storage chamber and the development chamber;
A developer carrying member disposed rotatably and carrying and carrying the developer in the developing chamber;
A developer storage section disposed below the developer carrier in the development chamber and storing the developer supplied to the development chamber through the opening;
A developer supply member that is disposed in the developing chamber and supplies the developer stored in the developer storage section to the developer carrier;
In a developing device comprising: a developer regulating member that is disposed so as to abut on the peripheral surface of the developer carrying member and regulates the layer thickness of the developer supplied on the developer carrying member;
The developer supply member is rotatably disposed so as to be in contact with the peripheral surface of the developer carrier, and moves in a direction opposite to the developer carrier in the contact region,
The developer carrying body is provided with a developer carrying surface having a plurality of convex portions configured to carry the developer and a concave portion surrounding each of the plurality of convex portions,
The height difference between the top surface of the convex portion and the bottom surface of the concave portion is 0.8 times or more and less than 5.0 times the weight average particle diameter (D4) of the developer,
On the developer carrying surface, when a virtual entire circumferential surface obtained by extending the top surface of the convex portion in the axial direction and the circumferential direction is defined, the top of the convex portion with respect to the area of the entire circumferential surface is defined. The ratio of the total area of the surface is 3% or more and less than 40%,
A contact position between the developer carrier and the developer regulating member is provided below a contact position between the developer carrier and the developer supply member;
Developing apparatus is characterized in that said developer carrying excess developer regulated by said developer regulating member from body, recovered in the developer storage portion.
The developer regulating member includes at least an elastic contact body having an end portion extending in a width direction parallel to the rotation axis of the developer carrying body,
In the state where the end portion of the elastic contact body faces the recess surrounding the convex portion on the surface of the developer carrying member, the distance between the end portion and the bottom surface of the recess is the weight average particle diameter (D4) of the developer. 2. The developing device according to claim 1, wherein the developing device is larger than 2.   3. The developing device according to claim 1, wherein a layer thickness of the developer carried on the top surface of the convex portion is restricted to one developer particle or less.   4. The surface hardness ratio of a contact portion of the developer regulating member with respect to the developer carrying member satisfies a relationship of 0.20 or more and less than 1.00. 5. Development device.   The developer storage chamber can be arranged below the developing chamber, the developer in the developer storage chamber can be pumped upward from below, and the developer can be supplied to the developing chamber through the opening. The developing device according to claim 1, further comprising a stirring member provided in the developer storage chamber. An electrostatic latent image carrier;
A process cartridge comprising: the developing device according to claim 1, which is integrally formed into a cartridge with the electrostatic latent image carrier.   An image forming apparatus comprising the developing device according to claim 1.