JP2011133665A - Developing device and developer carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that enables a satisfactory image to be formed by preventing, through a simple configuration, blotch caused by failure in developer layer formation under a low-temperature, low humidity environment, stably maintains image density over long term use, has an excellent development characteristic with stable environment stability, and enables an image of a high image quality to be formed all the time. <P>SOLUTION: The surface roughness of the outer circumferential surface of a developing sleeve is defined by a square means square radial tilt Δq and an arithmetic average roughness Ra. The value of Δq is 0.09≤Δq≤0.13, and the value of Ra is 0.55 μm≤Ra≤0.80 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a developing device and an image forming apparatus including a developer carrying member that carries and conveys a developer.

  In copiers and printers employing an electrophotographic system, a drum-shaped electrophotographic photosensitive member provided as an electrostatic latent image carrier, that is, a single component supplied from a developing device with a latent image formed on the surface of the photosensitive drum Development with a magnetic toner, which is a system developer, to make a visible image has been performed. In such a developing device, the toner particles are formed on the photosensitive drum by friction between toner particles, friction by a developer layer thickness regulating member (developing blade), friction between the developer carrier (developing sleeve) and magnetic toner particles, and the like. The magnetic toner particles are given a charge having the opposite polarity to the electrostatic image charge. Then, the magnetic toner is formed in a very thin layer on the developing sleeve and conveyed to a developing area formed by the photosensitive drum and the developing sleeve. Thereafter, in the developing region, the toner is caused to fly to the photosensitive drum side by the action of a magnetic field by a magnet fixed in the developing sleeve.

  As a developer carrying member (developing sleeve) used in such a developing device, a structure in which a coating made of carbon or resin containing at least a resin and graphite is conventionally coated (applied) on the outer peripheral surface of a cylindrical tube. What you have is known. According to the developing sleeve having such a configuration, by coating the outer peripheral surface with a paint such as carbon, it is possible to prevent contamination by the developer and external additives by appropriately scraping the outer peripheral surface. It becomes.

  On the other hand, in Patent Document 1, in order to prevent magnetic toner from partially aggregating and adhering to the contact portion between the developer layer thickness regulating member and the developer carrier, the surface of the outer peripheral surface of the developer carrier is disclosed. It has been proposed to define the roughness (relative uneven load length tp value, arithmetic average height Ra value) in an appropriate range.

JP 2007-147907 A

  However, even in the technique described in Patent Document 1, due to the contact and proximity of the developer layer thickness regulating member and the developer carrier, blotting due to poor layer formation of the developer occurs without being thinned and made uniform. . This blotch tends to occur remarkably in a low temperature and low humidity environment where the triboelectric charge amount of the developer tends to be large.

  Therefore, the present invention prevents the occurrence of blotches due to poor developer layer formation in a low-temperature and low-humidity environment with a simple configuration, stably maintains the image density over a long period of use, and develops with good environmental stability. An object of the present invention is to provide a developing device having characteristics and capable of forming a high-quality image.

  For this reason, the developer carrying member of the present invention has a square surface roughness of the surface carrying the developer in the developer carrying member that carries the developer and conveys the developer to another member. The mean square slope Δq is in the range of 0.09 ≦ Δq ≦ 0.13, and the arithmetic average roughness Ra is in the range of 0.55 μm ≦ Ra ≦ 0.80 μm.

Further, the developing device of the present invention includes a developer carrying member that carries the developer and conveys the developer to the other member, and forms an image with the developer.
The surface roughness of the developer-carrying surface of the developer carrier is such that the root mean square slope Δq is 0.09 ≦ Δq ≦ 0.13, and the arithmetic average roughness Ra is 0.55 μm ≦ Ra. It is formed in the range of ≦ 0.80 μm.

  According to the present invention, the surface of the developer carrying surface of the developer carrying member has a root mean square slope Δq of 0.09 ≦ Δq ≦ 0.13 and an arithmetic average roughness Ra of 0. .55 μm ≦ Ra ≦ 0.80 μm. This prevents the occurrence of blotches due to poor developer layer formation in a low-temperature, low-humidity environment with a simple structure, stably maintains image density over long-term use, and has development characteristics with good environmental stability. And a developing device capable of forming a high-quality image.

  Further, according to the present invention, the developing device has a surface roughness of the developer carrying surface of the developer carrying member, the root mean square slope Δq being in the range of 0.09 ≦ Δq ≦ 0.13, and the arithmetic mean The roughness Ra is formed in the range of 0.55 μm ≦ Ra ≦ 0.80 μm. This prevents the occurrence of blotches due to poor developer layer formation in a low-temperature, low-humidity environment with a simple structure, stably maintains image density over long-term use, and has development characteristics with good environmental stability. And a developing device capable of forming a high-quality image.

1 is a diagram illustrating a schematic configuration of an image forming apparatus adopting an electrophotographic method to which the present embodiment can be applied. It is a figure for demonstrating arithmetic average roughness: Ra. It is a figure for demonstrating root mean square inclination: (DELTA) q. (A) to (c) are enlarged cross-sectional views schematically showing an enlarged part of the outer peripheral surface shape of the developing sleeve. FIG. 7 is a table showing the relationship between the surface roughness (Ra value and Δq value) on the outer peripheral surface of the developing sleeve and the layer formation state and image quality state at that time. FIG. 6 is a table showing a relationship between the layer formation state and the image quality state with respect to the surface roughness when the surface roughness is set higher than the verification illustrated in FIG. 5. The graph shows the relationship between root mean square slope: Δq, arithmetic mean roughness: Ra, and the occurrence of blotches due to poor developer layer formation. The graph shows the relationship between root mean square slope: Δq, arithmetic mean roughness: Ra, and the occurrence of blotches due to poor developer layer formation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus adopting an electrophotographic system to which the present embodiment can be applied. The photosensitive drum 1 as an electrostatic latent image carrier is configured to be rotationally driven at a process speed (peripheral speed) of 100 to 300 mm / sec in the direction of an arrow a, for example. Around the photosensitive drum 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged in an annular shape in order along the rotation direction (the direction of arrow a). The charging device 2 includes, for example, a well-known charging roller, and has a function of uniformly charging the outer peripheral surface of the photosensitive drum 1 to a predetermined potential. The charging device 2 includes a charging bias application power source (charging member power source) 2a, and a predetermined bias voltage is applied to the cored bar 2b of the charging device 2 from the charging bias application power source 2a. The outer peripheral surface is uniformly charged to a predetermined polarity and potential by a contact charging method. The charging bias application power source 2a in the present embodiment employs an AC application method in which an AC voltage bias voltage (AC + DC) is applied to the charging device 2. In this system, a DC voltage component of −750 V and an AC current component of a frequency of 1200 Hz and a current of 1100 μA are applied to the charging device 2, so that the outer peripheral surface potential (charging potential and dark potential) of the photosensitive drum 1 is −600 V. To get to.

  The exposure apparatus 3 is composed of a well-known laser scanner or the like that is turned on / off in accordance with image data of an image to be recorded, for example, although a specific configuration diagram is omitted. This is because, as described above, the outer peripheral surface of the photosensitive drum 1 uniformly charged by the charging device 2 is exposed to a laser beam emitted from the exposure device 3 in accordance with an image signal, thereby causing electrostatic latent images on the outer peripheral surface of the photosensitive drum 1. An image is formed (the exposed part is Vl = -200V). The developing device 4 that develops the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 1 has a developing hopper 4a that is a developing container. Inside the developing hopper 4a, an electrostatic latent image carrier is provided. A developing sleeve 4b which is a developer carrying member disposed to face a certain photosensitive drum 1 is provided. Inside the developing sleeve 4b, a magnet roll 4c is fixedly disposed as a magnetic field generating means, and on the outer peripheral surface side of the developing sleeve 4b, a developing blade unit 10 is provided with a developer layer thickness regulating member. A blade 10a is provided. A magnetic developer T for visualizing the electrostatic latent image is supplied from a toner supply port 4d provided in the developing hopper 4a and is stored in the developing hopper 4a.

  As the magnetic developer T in the present embodiment, negatively chargeable magnetic one-component toner (hereinafter simply referred to as toner) is used. The toner includes, for example, 100 parts by weight of a styrene-n-butyl acrylate copolymer as a binder resin, 80 parts by weight of magnetic particles, 2 parts of a negative charge control agent of a monoazo iron complex, and 3 parts of a low molecular weight polypropylene as a wax. It is melt-kneaded with a twin screw extruder heated to 140 ° C, the cooled kneaded product is coarsely pulverized with a hammer mill, the coarsely pulverized product is finely pulverized with a jet mill, and the resulting finely pulverized product is air-classified. Then, after obtaining a classified powder having a weight average diameter of 5.0 μm, 1.0 part by weight of hydrophobic silica fine powder is mixed with a classified product having a volume average diameter of 5.0 μm by a Henschel mixer.

  The melt index (MI), which is an index of toner fixability, is set to 20 g / 10 min. The melt index (MI) at that time is measured by using an apparatus described in JIS-K7210 (an apparatus used for a thermoplastic flow test method). The conditions at that time are the measurement temperature: 125 ° C., the load: 5 kg, the sample filling amount: 5-10 g, measured by the manual cutting method, and the measured value at that time is converted to a 10-minute value. The average particle size of the toner was measured using a Coulter Multisizer II type (manufactured by Coulter). Further, as the toner used in the developing device 4 of the present embodiment, a toner having a range of MI 3 to 30 g / 10 min and a volume average particle size of 8.0 to 9.6 μm can be employed. On the other hand, the developing sleeve 4b arranged facing the photosensitive drum 1 is fixed so that the magnet roll 4c made of a multipolar permanent magnet does not rotate inside, and carries the toner T in a thin layer on the outer peripheral surface. However, it is configured to be rotationally driven in the direction of arrow b. Further, the developing sleeve 4b and the photosensitive drum 1 are arranged so that the distance between the two members faces each other with a gap of 300 μm at the closest position. On the outer peripheral surface of the developing sleeve 4b, a coating layer 4e containing conductive fine particles, which will be described later, is formed to a thickness of about 0.5 μm to 30 μm. Since the structure of the coating layer 4e is a main part of the present invention, it will be described in detail later.

  Further, on the outer peripheral surface of the developing sleeve 4b described above, a plate-like developing blade (developer amount regulating member) 10a provided in the developing blade unit 10 passes through the thin layer toner T on the outer peripheral surface of the developing sleeve 4b. Are arranged close to each other. When the free end portion of the developing blade 10a is brought close to a predetermined position on the outer peripheral surface of the developing sleeve 4b, a toner layer having a uniform thickness is thinned on the outer peripheral surface on the downstream side in the rotation direction of the developing sleeve 4b. It is formed in layers. At this time, the thin layered toner T is regulated by the magnetic blade 10a disposed at a distance W from the developing sleeve 4b, and is applied to the toner thin layer on the developing sleeve 4b. In general, the distance W is generally set in a range of 100 μm to 1 mm. Under such conditions, the toner amount (toner coat amount) W on the developing sleeve 4b was about 1.50 (mg / cm 2). Further, when developing the electrostatic latent image on the outer peripheral surface of the photosensitive drum 1 by the developing device 4 having the above-described configuration, an alternating voltage in which an alternating current is superimposed on a direct current is applied to a bias power source (not shown) on the above-described developing sleeve 4b. ) Is applied. The electrostatic latent image is developed by a developing electric field formed between the developing sleeve 4b and the photosensitive drum 1.

  In the present embodiment, a developing bias in which AC is superimposed on a DC voltage is applied to the developing sleeve 4b, and the developing device 4 performs reverse development with negatively chargeable toner, whereby an electrostatic latent image on the photosensitive drum 1 is formed. It is designed to be developed.

  On the other hand, the transfer device 5 includes a transfer roller 5a that is in contact with the photosensitive drum 1 described above, and a transfer power supply (not shown) that applies a transfer voltage having a positive polarity to the transfer roller 5a. The transfer roller 5a is formed by surrounding (surrounding) the outer peripheral surface of the conductive metal core 5b with a cylindrical sponge layer. Sulfurized one is used to make it conductive. The outer diameter of the sponge portion of the transfer roller 5a is set to φ16.0 mm, for example.

  The transfer device 5 is arranged in parallel to the photosensitive drum 1 and is brought into pressure contact with the photosensitive drum 1 with a predetermined pressing force by a pressing means (not shown). In the present embodiment, the rotation of the photosensitive drum 1 is performed. It is configured to be driven and rotated counterclockwise as it is driven. In this embodiment, the pressure nip portion between the photosensitive drum 1 and the transfer roller 5a is a transfer portion. The transfer material P fed from a paper feed unit (not shown) is fed to a transfer portion which is a pressure nip portion between the photosensitive drum 1 and the transfer roller 5a in accordance with a predetermined timing. That is, when the leading end of the toner image formed on the outer peripheral surface of the rotating photosensitive drum 1 reaches the transfer site, the transfer material P is transferred to the transfer site at the timing when the leading end of the transfer material P also reaches the transfer site. Be fed to. The transfer material P fed to the transfer site is nipped and conveyed by the transfer device 5 with its outer peripheral surface being in close contact with the photosensitive drum 1. From the time when the leading edge of the transfer material P reaches the transfer site until the trailing edge exits the transfer site, the core 5b of the transfer roller 5a has a polarity opposite to that of the toner from the transfer bias applying power source (transfer member power source). A predetermined DC bias is applied as a transfer bias. In this embodiment, a DC constant current of +7 μA is applied.

  In the process in which the transfer material P is nipped and conveyed, the toner image on the photosensitive drum 1 side is sequentially transferred to the transfer material P side by the action of the transfer electric field formed by the transfer roller 5a and the pressing force at the transfer portion. It will be done. Then, the transfer material P that has passed through the transfer portion and separated from the surface of the photosensitive drum 1 is conveyed to a fixing device (not shown) to fix the toner image, and then discharged to the outside of the apparatus main body, or the back surface. If the image is to be formed, it is conveyed to a re-conveying means to the transfer site.

  After the transfer is completed and the transfer material is separated, the outer peripheral surface of the photosensitive drum 1 is not transferred to the transfer material P and remains on the surface of the photosensitive drum 1 (transfer residual toner) and residual adhered contaminants such as paper dust. The surface is cleaned by a cleaning blade (not shown) of the cleaning device 6 for removing the surface. In this embodiment, the charging roller 2 and the transfer device 5 are driven and rotated by the photosensitive drum 1, but may be forcibly driven by driving means such as a motor with gears attached thereto.

  Next, the structure of the developing sleeve (developer carrier) 4b of the developing device 4 which is the main part of the present invention will be described in detail. When the developing device 4 is activated and the developing sleeve 4b rotates in the direction of arrow b, the contact friction between the toner T or the outer peripheral surface of the developing sleeve 4b and the toner T in the developing hopper 4a as a developing container (developer storage chamber). As a result, negative charge is applied to the toner T. Then, the toner T made into a thin layer by the developing blade 10a is conveyed to a developing area formed by the photosensitive drum 1 and the developing sleeve 4b. The thickness of the toner layer in the development region is thinner than the gap between the photosensitive drum 1 and the development sleeve 4b, and so-called non-contact development is performed. Here, as described above, the outer peripheral surface of the developing sleeve 4b is formed such that the coating layer 4e containing conductive fine particles has a thickness of about 0.5 μm to 30 μm. As the coating layer 4e, a coating-forming polymer material (resin) containing conductive fine particles is used, and the conductive fine particles at that time are crystalline graphite or crystalline graphite and carbon fine particles. Preferably there is. Further, as the film forming polymer material, thermoplastic resin (for example, styrene resin, vinyl resin, polyethersulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, fiber resin, acrylic resin, etc.) ), A thermosetting resin (for example, an epoxy resin, a polyester resin, an alkyd resin, a phenol resin, a melamine resin, a polyurethane resin, a urea resin, a silicon resin, a polyimide resin, or the like), a photocurable resin, or the like can be used. Among them, those having releasability such as silicon resin and fluororesin, and those having excellent mechanical properties such as polyethersulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin are more. preferable.

  Here, “blotch in poor developer layer formation”, which is a problem to be solved by the present invention, will be described. When the inventor of the present application closely observes the outer peripheral surface of the developing sleeve 4b when blotting due to poor developer layer formation occurs, the nip portion (hereinafter referred to as the blade nip) close to the outer peripheral surface of the developing sleeve 4b is observed. The toner caused a layer formation failure and showed a wavy shape. At that time, when the toner charge amount on the developing sleeve 4b (hereinafter referred to as “tribo”) was measured, it was found that the value was higher than that in a normal case. In other words, toner that is partially charged excessively other than normally charged toner tends to adhere to the developing sleeve 4b due to electrostatic mirror image force. Further, it is considered that electrostatic aggregation occurred between the overcharged toner and the normal charge amount toner in the blade nip portion, and the smooth formation of the toner layer was hindered.

  This phenomenon is caused by the fact that the surface area per unit volume increases as the particle size of the toner decreases, the surface area of the toner that can be charged increases, and the restraining force of the developing sleeve on the toner of the small particle size is weak, so It is thought that it is caused by moving. As a result, it was considered that “blotch due to poor developer layer formation” occurred.

  Therefore, the present inventor has obtained the following knowledge. In other words, in order to prevent the occurrence of such “blotting due to poor developer layer formation”, it is necessary to sufficiently restrain and secure the toner. For this purpose, the development sleeve is provided with a concavo-convex shape within a predetermined range. I thought it was necessary. These irregularities must have a sufficient restraining force for the toner in order to make the irregularities in which the toner hardly aggregates.

  Therefore, when verifying the unevenness with sufficient restraining force, a plurality of parameters defining the surface roughness were checked. The confirmed parameters are the maximum height Rmax, the ten-point average roughness Rz, the load length rate tp, the average interval Sm of the irregularities, the developed length rate lr, and the root mean square slope Δq. The occurrence of blotch was confirmed in combination with the average roughness Ra. As a result, it was found that the root mean square slope Δq, which is the standard deviation of the slope in the minute range of the unevenness, has the most influence on the occurrence of blotch. In other words, it has been found that when the inclination of each minute portion in the concavo-convex shape becomes steep, toner is secured in the developing sleeve and movement is restricted, so that it easily remains at a predetermined position. Therefore, it was considered that the occurrence of blotches can be effectively suppressed by defining the concavo-convex shape by the root mean square slope Δq and the arithmetic average roughness Ra.

(Root mean square slope and arithmetic mean roughness)
Here, the arithmetic average roughness Ra and the root mean square slope Δq will be described.
FIG. 2 is a diagram for explaining the arithmetic average roughness Ra, and FIG. 3 is a diagram for explaining the root mean square slope Δq. Arithmetic mean roughness Ra is a reference length L as shown in FIG.

And represents the average of the absolute values of f (x) at the reference length L of the concavo-convex shape.

  In addition, the root mean square slope Δq is as shown in FIG.

And represents the root mean square slope of the local slope d | f (x) | / dx of the concavo-convex shape.

  4A to 4C are enlarged sectional views schematically showing a part of the outer peripheral surface shape of the developing sleeve in an enlarged manner. 4 (a) and 4 (b) have the same root mean square slope Δq, but FIG. 4 (b) has a larger arithmetic mean roughness Ra and a different concavo-convex shape. 4 (a) and 4 (c) have the same arithmetic average roughness Ra, but FIG. 4 (c) has a smaller root mean square slope Δq than FIG. 4 (a).

  The root mean square slope Δq is a local slope with respect to the reference length L as shown in FIG. 4A and 4B, since the root mean square slope Δq is the same, the standard deviation of the local slope is the same, but the unevenness in FIG. 4A is compared with the unevenness in FIG. 4B. Since the arithmetic average roughness Ra is small, it has a minute slope valley. Further, in the concavo-convex shape as shown in FIG. 4C, the root mean square slope Δq is smaller than that in FIG. 4A, and the standard deviation of the slope is small, so that the undulation valley portion is uniform and more mirror-like. Close surface shape.

  In defining the concavo-convex shape by such arithmetic average roughness: Ra and root mean square slope Δq, the relationship between the concavo-convex shape and the occurrence of blotch due to poor developer (toner) layer formation was evaluated. In this evaluation, although no blotch occurred, the result that the tribo due to contact friction between the outer peripheral surface of the developing sleeve and the toner was not sufficiently obtained and the high image quality could not be maintained was described as image quality deterioration.

  FIG. 5 is a table showing the relationship between the surface roughness (Ra value and Δq value) on the outer peripheral surface of the developing sleeve 4b, and the layer formation state and image quality state at that time. Comparing the verification I and the verification II, it can be seen that the arithmetic average roughness Ra is the same, but there is a difference in the occurrence of blotches due to poor layer formation depending on the value of the root mean square slope Δq. Further, from the verification II and the verification III, it can be seen that even if the root mean square slope Δq is the same, there is a difference in the occurrence of blotches due to poor layer formation depending on the value of the arithmetic average roughness Ra.

  FIG. 6 is a table showing the relationship between the layer formation state and the image quality state with respect to the surface roughness when the surface roughness is set higher than the verification shown in FIG. Even with the same Ra value from verification IV and verification V, due to the difference in Δq value, blotting due to defective layer formation of the developer did not occur, but sufficient tribo was not obtained, and the output image was deteriorated. In addition, even if Δq is the same value from the verification V and the verification VI, a sufficient amount of tribo cannot be obtained due to the difference in Ra, and the output image was deteriorated.

  As a result of these verifications, the blotch due to poor developer layer formation is such that the root mean square slope Δq is small as shown in FIG. 4C even if the arithmetic average roughness Ra is in a range sufficient to obtain good image quality. It became clear that it occurred remarkably in the uneven shape on the outer peripheral surface. This is because, as shown in FIG. 4C, the uneven slope on the outer peripheral surface is small and close to a mirror surface state, thereby reducing the amount of toner carried on the developing sleeve and increasing the toner charge amount per unit weight. This is considered to be caused by the fact that fine toner accumulates more electric charge. However, since FIG. 4C does not include the undulation valley portion having the inclination of the minute portion that holds the finely powdered toner that has become the overcharged toner, electrostatic aggregation occurs with the normal toner, It is estimated that defective layer formation occurs. On the other hand, it is presumed that poor formation of the layer does not occur because the toner having a charge amount capable of obtaining a good image quality can be sufficiently retained if the undulation valley portion having a minute portion slope is provided.

  Here, in order to find an optimal region where no layer formation failure occurs, the values of the root mean square slope Δq and the arithmetic average roughness Ra were varied, and the layer formation state and the image state at each value were confirmed.

  FIG. 7 is a graph summarizing the relationship between the root mean square slope Δq, the arithmetic mean roughness Ra, and the occurrence of blotches due to poor developer layer formation based on the above verification. In the table, the horizontal axis represents the root mean square slope Δq, and the vertical axis represents the arithmetic average roughness Ra. In this graph, ◯ indicates that no blotch occurs due to poor toner layer formation, and X indicates that it does not occur, and Δ indicates that the output image deteriorates although no blotch occurs due to poor developer layer formation. Here, confirmation was performed using a toner having a volume average particle diameter of 9.6 μm.

  FIG. 8 shows a mean square slope Δq, an arithmetic average roughness Ra, and a blotch due to poor developer layer formation when the average particle size of the toner is reduced and a toner having a volume average particle size of 8.0 μm is used. It is a graph that summarizes the relationship with the occurrence of

From these graphs, the appropriate range of the root mean square slope Δq and the arithmetic mean roughness Ra is such that Δq is in the range of 0.09 ≦ Δq ≦ 0.13, and Ra is 0.55 μm ≦ Ra ≦ 0.80 μm. In the range, it was found that the occurrence of blotches due to poor developer layer formation can be suppressed. The charge amount Q / M per unit weight of the developer on the developing sleeve at this time is in the range of −20 μC / g ≦ Q / M ≦ −3 μC / g, and the coating amount M / S per unit area. Was in the range of 0.5 mg / cm ⁻² ≦ M / S ≦ 2.5 mg / cm ⁻² .

  Although the occurrence of blotches could be suppressed, the toner aggregation is considered to occur within a range where it cannot be visually recognized, and the occurrence rate is considered to be extremely low. Further, the particle size distribution of the toner used in this verification is a distribution including almost all the particle size of the toner used in image formation by electrophotography today.

(Production of development sleeve)
Hereinafter, an example of a method for producing a developing sleeve to which this embodiment can be applied will be described. However, the present invention is not limited to this. It was formed by uniformly coating the coating layer produced as follows on the outer peripheral surface of an aluminum cylindrical tube (sleeve) formed as the original material of the developing sleeve 4b.
Phenolic resin ... 100 parts by weight Graphite ...・ ・ ・ ・ 80 parts by weight Carbon black ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 20 parts by weight Coarse particles (5 μm) ... 15 parts by weight Charge control agent (CA agent) ... 5 parts by weight

  The coating material formulated as described above is dispersed and mixed in 250 parts by weight of a methanol / butanol (1: 1) mixed solvent using a sand mill to form a paint. Then, a coating layer 4e was uniformly formed on the outer peripheral surface of an aluminum cylindrical tube (sleeve) by an air spray method so as to have a film thickness of 10 μm, and dried to obtain a developing sleeve 4b. The surface roughness of the outer peripheral surface of the developing sleeve 4b formed as described above was measured using a surface roughness meter (manufactured by Kosaka Laboratory, Surfcoder SE-30H type). The measurement at that time was performed with a cut-off of 0.8 mm, a measurement distance of 8.0 mm, and a feed rate of 0.5 mm / sec.

  Development is performed in an environment of an air temperature of 15 ° C. and a humidity of 10% RH using the developing sleeve thus produced.

  Thus, the surface roughness of the outer peripheral surface of the developing sleeve is defined by the root mean square slope Δq and the arithmetic average roughness Ra, the value of Δq is 0.09 ≦ Δq ≦ 0.13, and the value of Ra is 0.55 μm ≦ Ra ≦ 0.80 μm. A developing device using the developing sleeve thus formed is produced. This prevents the occurrence of blotches due to poor developer layer formation in a low-temperature, low-humidity environment with a simple structure, stably maintains image density over long-term use, and has development characteristics with good environmental stability. And a developing device capable of forming a high-quality image.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging apparatus 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus

Claims (5)

  In the developer carrying member that carries the developer and conveys the developer to another member, the surface roughness of the surface carrying the developer has a root mean square slope Δq of 0.09 ≦ Δq. A developer carrier characterized by being in a range of ≦ 0.13 and having an arithmetic average roughness Ra in a range of 0.55 μm ≦ Ra ≦ 0.80 μm. In a developing apparatus that includes a developer carrying member that carries the developer and conveys the developer to another member, and forms an image with the developer.
The surface roughness of the developer-carrying surface of the developer carrier is such that the root mean square slope Δq is 0.09 ≦ Δq ≦ 0.13, and the arithmetic average roughness Ra is 0.55 μm ≦ Ra. A developing device characterized by being formed in a range of ≦ 0.80 μm.   3. The developing device according to claim 2, wherein a surface of the developer carrying member carrying the developer is formed by coating a coating layer containing a resin and graphite on an outer peripheral surface of a cylindrical tube. .   The developer carrying member having a magnetic field generating means fixed inside, and the thickness of the developer layer carried on the surface carrying the developer in the vicinity of the developer carrying member are regulated. The developing device according to claim 2, further comprising a developer layer thickness regulating member. The charge amount Q / M per unit weight of the developer on the surface, the layer thickness of which is defined by the developer layer thickness regulating member, is −20 μC / g ≦ Q / M ≦ −3 μC / g. 5. The coating amount M / S per unit area on the surface is in the range of 0.5 mg / cm ⁻² ≦ M / S ≦ 2.5 mg / cm ^−2. The developing device described.

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